xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision 08193d1a)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/net/sunrpc/xprtsock.c
4  *
5  * Client-side transport implementation for sockets.
6  *
7  * TCP callback races fixes (C) 1998 Red Hat
8  * TCP send fixes (C) 1998 Red Hat
9  * TCP NFS related read + write fixes
10  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
11  *
12  * Rewrite of larges part of the code in order to stabilize TCP stuff.
13  * Fix behaviour when socket buffer is full.
14  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
15  *
16  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
17  *
18  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
19  *   <gilles.quillard@bull.net>
20  */
21 
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/capability.h>
27 #include <linux/pagemap.h>
28 #include <linux/errno.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/net.h>
32 #include <linux/mm.h>
33 #include <linux/un.h>
34 #include <linux/udp.h>
35 #include <linux/tcp.h>
36 #include <linux/sunrpc/clnt.h>
37 #include <linux/sunrpc/addr.h>
38 #include <linux/sunrpc/sched.h>
39 #include <linux/sunrpc/svcsock.h>
40 #include <linux/sunrpc/xprtsock.h>
41 #include <linux/file.h>
42 #ifdef CONFIG_SUNRPC_BACKCHANNEL
43 #include <linux/sunrpc/bc_xprt.h>
44 #endif
45 
46 #include <net/sock.h>
47 #include <net/checksum.h>
48 #include <net/udp.h>
49 #include <net/tcp.h>
50 
51 #include <trace/events/sunrpc.h>
52 
53 #include "sunrpc.h"
54 
55 #define RPC_TCP_READ_CHUNK_SZ	(3*512*1024)
56 
57 static void xs_close(struct rpc_xprt *xprt);
58 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
59 		struct socket *sock);
60 
61 /*
62  * xprtsock tunables
63  */
64 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
65 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
66 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
67 
68 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
69 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
70 
71 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
72 
73 #define XS_TCP_LINGER_TO	(15U * HZ)
74 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
75 
76 /*
77  * We can register our own files under /proc/sys/sunrpc by
78  * calling register_sysctl_table() again.  The files in that
79  * directory become the union of all files registered there.
80  *
81  * We simply need to make sure that we don't collide with
82  * someone else's file names!
83  */
84 
85 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
86 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
87 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
88 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
89 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
90 
91 static struct ctl_table_header *sunrpc_table_header;
92 
93 /*
94  * FIXME: changing the UDP slot table size should also resize the UDP
95  *        socket buffers for existing UDP transports
96  */
97 static struct ctl_table xs_tunables_table[] = {
98 	{
99 		.procname	= "udp_slot_table_entries",
100 		.data		= &xprt_udp_slot_table_entries,
101 		.maxlen		= sizeof(unsigned int),
102 		.mode		= 0644,
103 		.proc_handler	= proc_dointvec_minmax,
104 		.extra1		= &min_slot_table_size,
105 		.extra2		= &max_slot_table_size
106 	},
107 	{
108 		.procname	= "tcp_slot_table_entries",
109 		.data		= &xprt_tcp_slot_table_entries,
110 		.maxlen		= sizeof(unsigned int),
111 		.mode		= 0644,
112 		.proc_handler	= proc_dointvec_minmax,
113 		.extra1		= &min_slot_table_size,
114 		.extra2		= &max_slot_table_size
115 	},
116 	{
117 		.procname	= "tcp_max_slot_table_entries",
118 		.data		= &xprt_max_tcp_slot_table_entries,
119 		.maxlen		= sizeof(unsigned int),
120 		.mode		= 0644,
121 		.proc_handler	= proc_dointvec_minmax,
122 		.extra1		= &min_slot_table_size,
123 		.extra2		= &max_tcp_slot_table_limit
124 	},
125 	{
126 		.procname	= "min_resvport",
127 		.data		= &xprt_min_resvport,
128 		.maxlen		= sizeof(unsigned int),
129 		.mode		= 0644,
130 		.proc_handler	= proc_dointvec_minmax,
131 		.extra1		= &xprt_min_resvport_limit,
132 		.extra2		= &xprt_max_resvport
133 	},
134 	{
135 		.procname	= "max_resvport",
136 		.data		= &xprt_max_resvport,
137 		.maxlen		= sizeof(unsigned int),
138 		.mode		= 0644,
139 		.proc_handler	= proc_dointvec_minmax,
140 		.extra1		= &xprt_min_resvport,
141 		.extra2		= &xprt_max_resvport_limit
142 	},
143 	{
144 		.procname	= "tcp_fin_timeout",
145 		.data		= &xs_tcp_fin_timeout,
146 		.maxlen		= sizeof(xs_tcp_fin_timeout),
147 		.mode		= 0644,
148 		.proc_handler	= proc_dointvec_jiffies,
149 	},
150 	{ },
151 };
152 
153 static struct ctl_table sunrpc_table[] = {
154 	{
155 		.procname	= "sunrpc",
156 		.mode		= 0555,
157 		.child		= xs_tunables_table
158 	},
159 	{ },
160 };
161 
162 #endif
163 
164 /*
165  * Wait duration for a reply from the RPC portmapper.
166  */
167 #define XS_BIND_TO		(60U * HZ)
168 
169 /*
170  * Delay if a UDP socket connect error occurs.  This is most likely some
171  * kind of resource problem on the local host.
172  */
173 #define XS_UDP_REEST_TO		(2U * HZ)
174 
175 /*
176  * The reestablish timeout allows clients to delay for a bit before attempting
177  * to reconnect to a server that just dropped our connection.
178  *
179  * We implement an exponential backoff when trying to reestablish a TCP
180  * transport connection with the server.  Some servers like to drop a TCP
181  * connection when they are overworked, so we start with a short timeout and
182  * increase over time if the server is down or not responding.
183  */
184 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
185 
186 /*
187  * TCP idle timeout; client drops the transport socket if it is idle
188  * for this long.  Note that we also timeout UDP sockets to prevent
189  * holding port numbers when there is no RPC traffic.
190  */
191 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
192 
193 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
194 # undef  RPC_DEBUG_DATA
195 # define RPCDBG_FACILITY	RPCDBG_TRANS
196 #endif
197 
198 #ifdef RPC_DEBUG_DATA
199 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
200 {
201 	u8 *buf = (u8 *) packet;
202 	int j;
203 
204 	dprintk("RPC:       %s\n", msg);
205 	for (j = 0; j < count && j < 128; j += 4) {
206 		if (!(j & 31)) {
207 			if (j)
208 				dprintk("\n");
209 			dprintk("0x%04x ", j);
210 		}
211 		dprintk("%02x%02x%02x%02x ",
212 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
213 	}
214 	dprintk("\n");
215 }
216 #else
217 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
218 {
219 	/* NOP */
220 }
221 #endif
222 
223 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
224 {
225 	return (struct rpc_xprt *) sk->sk_user_data;
226 }
227 
228 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
229 {
230 	return (struct sockaddr *) &xprt->addr;
231 }
232 
233 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
234 {
235 	return (struct sockaddr_un *) &xprt->addr;
236 }
237 
238 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
239 {
240 	return (struct sockaddr_in *) &xprt->addr;
241 }
242 
243 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
244 {
245 	return (struct sockaddr_in6 *) &xprt->addr;
246 }
247 
248 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
249 {
250 	struct sockaddr *sap = xs_addr(xprt);
251 	struct sockaddr_in6 *sin6;
252 	struct sockaddr_in *sin;
253 	struct sockaddr_un *sun;
254 	char buf[128];
255 
256 	switch (sap->sa_family) {
257 	case AF_LOCAL:
258 		sun = xs_addr_un(xprt);
259 		strlcpy(buf, sun->sun_path, sizeof(buf));
260 		xprt->address_strings[RPC_DISPLAY_ADDR] =
261 						kstrdup(buf, GFP_KERNEL);
262 		break;
263 	case AF_INET:
264 		(void)rpc_ntop(sap, buf, sizeof(buf));
265 		xprt->address_strings[RPC_DISPLAY_ADDR] =
266 						kstrdup(buf, GFP_KERNEL);
267 		sin = xs_addr_in(xprt);
268 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
269 		break;
270 	case AF_INET6:
271 		(void)rpc_ntop(sap, buf, sizeof(buf));
272 		xprt->address_strings[RPC_DISPLAY_ADDR] =
273 						kstrdup(buf, GFP_KERNEL);
274 		sin6 = xs_addr_in6(xprt);
275 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
276 		break;
277 	default:
278 		BUG();
279 	}
280 
281 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
282 }
283 
284 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
285 {
286 	struct sockaddr *sap = xs_addr(xprt);
287 	char buf[128];
288 
289 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
290 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
291 
292 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
293 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
294 }
295 
296 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
297 				     const char *protocol,
298 				     const char *netid)
299 {
300 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
301 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
302 	xs_format_common_peer_addresses(xprt);
303 	xs_format_common_peer_ports(xprt);
304 }
305 
306 static void xs_update_peer_port(struct rpc_xprt *xprt)
307 {
308 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
309 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
310 
311 	xs_format_common_peer_ports(xprt);
312 }
313 
314 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
315 {
316 	unsigned int i;
317 
318 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
319 		switch (i) {
320 		case RPC_DISPLAY_PROTO:
321 		case RPC_DISPLAY_NETID:
322 			continue;
323 		default:
324 			kfree(xprt->address_strings[i]);
325 		}
326 }
327 
328 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
329 
330 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
331 {
332 	struct msghdr msg = {
333 		.msg_name	= addr,
334 		.msg_namelen	= addrlen,
335 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
336 	};
337 	struct kvec iov = {
338 		.iov_base	= vec->iov_base + base,
339 		.iov_len	= vec->iov_len - base,
340 	};
341 
342 	if (iov.iov_len != 0)
343 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
344 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
345 }
346 
347 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
348 {
349 	ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
350 			int offset, size_t size, int flags);
351 	struct page **ppage;
352 	unsigned int remainder;
353 	int err;
354 
355 	remainder = xdr->page_len - base;
356 	base += xdr->page_base;
357 	ppage = xdr->pages + (base >> PAGE_SHIFT);
358 	base &= ~PAGE_MASK;
359 	do_sendpage = sock->ops->sendpage;
360 	if (!zerocopy)
361 		do_sendpage = sock_no_sendpage;
362 	for(;;) {
363 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
364 		int flags = XS_SENDMSG_FLAGS;
365 
366 		remainder -= len;
367 		if (more)
368 			flags |= MSG_MORE;
369 		if (remainder != 0)
370 			flags |= MSG_SENDPAGE_NOTLAST | MSG_MORE;
371 		err = do_sendpage(sock, *ppage, base, len, flags);
372 		if (remainder == 0 || err != len)
373 			break;
374 		*sent_p += err;
375 		ppage++;
376 		base = 0;
377 	}
378 	if (err > 0) {
379 		*sent_p += err;
380 		err = 0;
381 	}
382 	return err;
383 }
384 
385 /**
386  * xs_sendpages - write pages directly to a socket
387  * @sock: socket to send on
388  * @addr: UDP only -- address of destination
389  * @addrlen: UDP only -- length of destination address
390  * @xdr: buffer containing this request
391  * @base: starting position in the buffer
392  * @zerocopy: true if it is safe to use sendpage()
393  * @sent_p: return the total number of bytes successfully queued for sending
394  *
395  */
396 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
397 {
398 	unsigned int remainder = xdr->len - base;
399 	int err = 0;
400 	int sent = 0;
401 
402 	if (unlikely(!sock))
403 		return -ENOTSOCK;
404 
405 	if (base != 0) {
406 		addr = NULL;
407 		addrlen = 0;
408 	}
409 
410 	if (base < xdr->head[0].iov_len || addr != NULL) {
411 		unsigned int len = xdr->head[0].iov_len - base;
412 		remainder -= len;
413 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
414 		if (remainder == 0 || err != len)
415 			goto out;
416 		*sent_p += err;
417 		base = 0;
418 	} else
419 		base -= xdr->head[0].iov_len;
420 
421 	if (base < xdr->page_len) {
422 		unsigned int len = xdr->page_len - base;
423 		remainder -= len;
424 		err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
425 		*sent_p += sent;
426 		if (remainder == 0 || sent != len)
427 			goto out;
428 		base = 0;
429 	} else
430 		base -= xdr->page_len;
431 
432 	if (base >= xdr->tail[0].iov_len)
433 		return 0;
434 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
435 out:
436 	if (err > 0) {
437 		*sent_p += err;
438 		err = 0;
439 	}
440 	return err;
441 }
442 
443 static void xs_nospace_callback(struct rpc_task *task)
444 {
445 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
446 
447 	transport->inet->sk_write_pending--;
448 }
449 
450 /**
451  * xs_nospace - place task on wait queue if transmit was incomplete
452  * @task: task to put to sleep
453  *
454  */
455 static int xs_nospace(struct rpc_task *task)
456 {
457 	struct rpc_rqst *req = task->tk_rqstp;
458 	struct rpc_xprt *xprt = req->rq_xprt;
459 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
460 	struct sock *sk = transport->inet;
461 	int ret = -EAGAIN;
462 
463 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
464 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
465 			req->rq_slen);
466 
467 	/* Protect against races with write_space */
468 	spin_lock_bh(&xprt->transport_lock);
469 
470 	/* Don't race with disconnect */
471 	if (xprt_connected(xprt)) {
472 		/* wait for more buffer space */
473 		sk->sk_write_pending++;
474 		xprt_wait_for_buffer_space(task, xs_nospace_callback);
475 	} else
476 		ret = -ENOTCONN;
477 
478 	spin_unlock_bh(&xprt->transport_lock);
479 
480 	/* Race breaker in case memory is freed before above code is called */
481 	if (ret == -EAGAIN) {
482 		struct socket_wq *wq;
483 
484 		rcu_read_lock();
485 		wq = rcu_dereference(sk->sk_wq);
486 		set_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags);
487 		rcu_read_unlock();
488 
489 		sk->sk_write_space(sk);
490 	}
491 	return ret;
492 }
493 
494 /*
495  * Construct a stream transport record marker in @buf.
496  */
497 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
498 {
499 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
500 	rpc_fraghdr *base = buf->head[0].iov_base;
501 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
502 }
503 
504 /**
505  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
506  * @task: RPC task that manages the state of an RPC request
507  *
508  * Return values:
509  *        0:	The request has been sent
510  *   EAGAIN:	The socket was blocked, please call again later to
511  *		complete the request
512  * ENOTCONN:	Caller needs to invoke connect logic then call again
513  *    other:	Some other error occured, the request was not sent
514  */
515 static int xs_local_send_request(struct rpc_task *task)
516 {
517 	struct rpc_rqst *req = task->tk_rqstp;
518 	struct rpc_xprt *xprt = req->rq_xprt;
519 	struct sock_xprt *transport =
520 				container_of(xprt, struct sock_xprt, xprt);
521 	struct xdr_buf *xdr = &req->rq_snd_buf;
522 	int status;
523 	int sent = 0;
524 
525 	xs_encode_stream_record_marker(&req->rq_snd_buf);
526 
527 	xs_pktdump("packet data:",
528 			req->rq_svec->iov_base, req->rq_svec->iov_len);
529 
530 	req->rq_xtime = ktime_get();
531 	status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
532 			      true, &sent);
533 	dprintk("RPC:       %s(%u) = %d\n",
534 			__func__, xdr->len - req->rq_bytes_sent, status);
535 
536 	if (status == -EAGAIN && sock_writeable(transport->inet))
537 		status = -ENOBUFS;
538 
539 	if (likely(sent > 0) || status == 0) {
540 		req->rq_bytes_sent += sent;
541 		req->rq_xmit_bytes_sent += sent;
542 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
543 			req->rq_bytes_sent = 0;
544 			return 0;
545 		}
546 		status = -EAGAIN;
547 	}
548 
549 	switch (status) {
550 	case -ENOBUFS:
551 		break;
552 	case -EAGAIN:
553 		status = xs_nospace(task);
554 		break;
555 	default:
556 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
557 			-status);
558 		/* fall through */
559 	case -EPIPE:
560 		xs_close(xprt);
561 		status = -ENOTCONN;
562 	}
563 
564 	return status;
565 }
566 
567 /**
568  * xs_udp_send_request - write an RPC request to a UDP socket
569  * @task: address of RPC task that manages the state of an RPC request
570  *
571  * Return values:
572  *        0:	The request has been sent
573  *   EAGAIN:	The socket was blocked, please call again later to
574  *		complete the request
575  * ENOTCONN:	Caller needs to invoke connect logic then call again
576  *    other:	Some other error occurred, the request was not sent
577  */
578 static int xs_udp_send_request(struct rpc_task *task)
579 {
580 	struct rpc_rqst *req = task->tk_rqstp;
581 	struct rpc_xprt *xprt = req->rq_xprt;
582 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
583 	struct xdr_buf *xdr = &req->rq_snd_buf;
584 	int sent = 0;
585 	int status;
586 
587 	xs_pktdump("packet data:",
588 				req->rq_svec->iov_base,
589 				req->rq_svec->iov_len);
590 
591 	if (!xprt_bound(xprt))
592 		return -ENOTCONN;
593 	req->rq_xtime = ktime_get();
594 	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
595 			      xdr, req->rq_bytes_sent, true, &sent);
596 
597 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
598 			xdr->len - req->rq_bytes_sent, status);
599 
600 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
601 	if (status == -EPERM)
602 		goto process_status;
603 
604 	if (status == -EAGAIN && sock_writeable(transport->inet))
605 		status = -ENOBUFS;
606 
607 	if (sent > 0 || status == 0) {
608 		req->rq_xmit_bytes_sent += sent;
609 		if (sent >= req->rq_slen)
610 			return 0;
611 		/* Still some bytes left; set up for a retry later. */
612 		status = -EAGAIN;
613 	}
614 
615 process_status:
616 	switch (status) {
617 	case -ENOTSOCK:
618 		status = -ENOTCONN;
619 		/* Should we call xs_close() here? */
620 		break;
621 	case -EAGAIN:
622 		status = xs_nospace(task);
623 		break;
624 	case -ENETUNREACH:
625 	case -ENOBUFS:
626 	case -EPIPE:
627 	case -ECONNREFUSED:
628 	case -EPERM:
629 		/* When the server has died, an ICMP port unreachable message
630 		 * prompts ECONNREFUSED. */
631 		break;
632 	default:
633 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
634 			-status);
635 	}
636 
637 	return status;
638 }
639 
640 /**
641  * xs_tcp_send_request - write an RPC request to a TCP socket
642  * @task: address of RPC task that manages the state of an RPC request
643  *
644  * Return values:
645  *        0:	The request has been sent
646  *   EAGAIN:	The socket was blocked, please call again later to
647  *		complete the request
648  * ENOTCONN:	Caller needs to invoke connect logic then call again
649  *    other:	Some other error occurred, the request was not sent
650  *
651  * XXX: In the case of soft timeouts, should we eventually give up
652  *	if sendmsg is not able to make progress?
653  */
654 static int xs_tcp_send_request(struct rpc_task *task)
655 {
656 	struct rpc_rqst *req = task->tk_rqstp;
657 	struct rpc_xprt *xprt = req->rq_xprt;
658 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
659 	struct xdr_buf *xdr = &req->rq_snd_buf;
660 	bool zerocopy = true;
661 	bool vm_wait = false;
662 	int status;
663 	int sent;
664 
665 	xs_encode_stream_record_marker(&req->rq_snd_buf);
666 
667 	xs_pktdump("packet data:",
668 				req->rq_svec->iov_base,
669 				req->rq_svec->iov_len);
670 	/* Don't use zero copy if this is a resend. If the RPC call
671 	 * completes while the socket holds a reference to the pages,
672 	 * then we may end up resending corrupted data.
673 	 */
674 	if (task->tk_flags & RPC_TASK_SENT)
675 		zerocopy = false;
676 
677 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
678 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
679 
680 	/* Continue transmitting the packet/record. We must be careful
681 	 * to cope with writespace callbacks arriving _after_ we have
682 	 * called sendmsg(). */
683 	req->rq_xtime = ktime_get();
684 	while (1) {
685 		sent = 0;
686 		status = xs_sendpages(transport->sock, NULL, 0, xdr,
687 				      req->rq_bytes_sent, zerocopy, &sent);
688 
689 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
690 				xdr->len - req->rq_bytes_sent, status);
691 
692 		/* If we've sent the entire packet, immediately
693 		 * reset the count of bytes sent. */
694 		req->rq_bytes_sent += sent;
695 		req->rq_xmit_bytes_sent += sent;
696 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
697 			req->rq_bytes_sent = 0;
698 			return 0;
699 		}
700 
701 		WARN_ON_ONCE(sent == 0 && status == 0);
702 
703 		if (status == -EAGAIN ) {
704 			/*
705 			 * Return EAGAIN if we're sure we're hitting the
706 			 * socket send buffer limits.
707 			 */
708 			if (test_bit(SOCK_NOSPACE, &transport->sock->flags))
709 				break;
710 			/*
711 			 * Did we hit a memory allocation failure?
712 			 */
713 			if (sent == 0) {
714 				status = -ENOBUFS;
715 				if (vm_wait)
716 					break;
717 				/* Retry, knowing now that we're below the
718 				 * socket send buffer limit
719 				 */
720 				vm_wait = true;
721 			}
722 			continue;
723 		}
724 		if (status < 0)
725 			break;
726 		vm_wait = false;
727 	}
728 
729 	switch (status) {
730 	case -ENOTSOCK:
731 		status = -ENOTCONN;
732 		/* Should we call xs_close() here? */
733 		break;
734 	case -EAGAIN:
735 		status = xs_nospace(task);
736 		break;
737 	case -ECONNRESET:
738 	case -ECONNREFUSED:
739 	case -ENOTCONN:
740 	case -EADDRINUSE:
741 	case -ENOBUFS:
742 	case -EPIPE:
743 		break;
744 	default:
745 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
746 			-status);
747 	}
748 
749 	return status;
750 }
751 
752 /**
753  * xs_tcp_release_xprt - clean up after a tcp transmission
754  * @xprt: transport
755  * @task: rpc task
756  *
757  * This cleans up if an error causes us to abort the transmission of a request.
758  * In this case, the socket may need to be reset in order to avoid confusing
759  * the server.
760  */
761 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
762 {
763 	struct rpc_rqst *req;
764 
765 	if (task != xprt->snd_task)
766 		return;
767 	if (task == NULL)
768 		goto out_release;
769 	req = task->tk_rqstp;
770 	if (req == NULL)
771 		goto out_release;
772 	if (req->rq_bytes_sent == 0)
773 		goto out_release;
774 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
775 		goto out_release;
776 	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
777 out_release:
778 	xprt_release_xprt(xprt, task);
779 }
780 
781 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
782 {
783 	transport->old_data_ready = sk->sk_data_ready;
784 	transport->old_state_change = sk->sk_state_change;
785 	transport->old_write_space = sk->sk_write_space;
786 	transport->old_error_report = sk->sk_error_report;
787 }
788 
789 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
790 {
791 	sk->sk_data_ready = transport->old_data_ready;
792 	sk->sk_state_change = transport->old_state_change;
793 	sk->sk_write_space = transport->old_write_space;
794 	sk->sk_error_report = transport->old_error_report;
795 }
796 
797 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
798 {
799 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
800 
801 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
802 }
803 
804 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
805 {
806 	smp_mb__before_atomic();
807 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
808 	clear_bit(XPRT_CLOSING, &xprt->state);
809 	xs_sock_reset_state_flags(xprt);
810 	smp_mb__after_atomic();
811 }
812 
813 /**
814  * xs_error_report - callback to handle TCP socket state errors
815  * @sk: socket
816  *
817  * Note: we don't call sock_error() since there may be a rpc_task
818  * using the socket, and so we don't want to clear sk->sk_err.
819  */
820 static void xs_error_report(struct sock *sk)
821 {
822 	struct rpc_xprt *xprt;
823 	int err;
824 
825 	read_lock_bh(&sk->sk_callback_lock);
826 	if (!(xprt = xprt_from_sock(sk)))
827 		goto out;
828 
829 	err = -sk->sk_err;
830 	if (err == 0)
831 		goto out;
832 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
833 			xprt, -err);
834 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
835 	xprt_wake_pending_tasks(xprt, err);
836  out:
837 	read_unlock_bh(&sk->sk_callback_lock);
838 }
839 
840 static void xs_reset_transport(struct sock_xprt *transport)
841 {
842 	struct socket *sock = transport->sock;
843 	struct sock *sk = transport->inet;
844 	struct rpc_xprt *xprt = &transport->xprt;
845 
846 	if (sk == NULL)
847 		return;
848 
849 	if (atomic_read(&transport->xprt.swapper))
850 		sk_clear_memalloc(sk);
851 
852 	kernel_sock_shutdown(sock, SHUT_RDWR);
853 
854 	mutex_lock(&transport->recv_mutex);
855 	write_lock_bh(&sk->sk_callback_lock);
856 	transport->inet = NULL;
857 	transport->sock = NULL;
858 
859 	sk->sk_user_data = NULL;
860 
861 	xs_restore_old_callbacks(transport, sk);
862 	xprt_clear_connected(xprt);
863 	write_unlock_bh(&sk->sk_callback_lock);
864 	xs_sock_reset_connection_flags(xprt);
865 	mutex_unlock(&transport->recv_mutex);
866 
867 	trace_rpc_socket_close(xprt, sock);
868 	sock_release(sock);
869 }
870 
871 /**
872  * xs_close - close a socket
873  * @xprt: transport
874  *
875  * This is used when all requests are complete; ie, no DRC state remains
876  * on the server we want to save.
877  *
878  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
879  * xs_reset_transport() zeroing the socket from underneath a writer.
880  */
881 static void xs_close(struct rpc_xprt *xprt)
882 {
883 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
884 
885 	dprintk("RPC:       xs_close xprt %p\n", xprt);
886 
887 	xs_reset_transport(transport);
888 	xprt->reestablish_timeout = 0;
889 
890 	xprt_disconnect_done(xprt);
891 }
892 
893 static void xs_inject_disconnect(struct rpc_xprt *xprt)
894 {
895 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
896 		xprt);
897 	xprt_disconnect_done(xprt);
898 }
899 
900 static void xs_xprt_free(struct rpc_xprt *xprt)
901 {
902 	xs_free_peer_addresses(xprt);
903 	xprt_free(xprt);
904 }
905 
906 /**
907  * xs_destroy - prepare to shutdown a transport
908  * @xprt: doomed transport
909  *
910  */
911 static void xs_destroy(struct rpc_xprt *xprt)
912 {
913 	struct sock_xprt *transport = container_of(xprt,
914 			struct sock_xprt, xprt);
915 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
916 
917 	cancel_delayed_work_sync(&transport->connect_worker);
918 	xs_close(xprt);
919 	cancel_work_sync(&transport->recv_worker);
920 	xs_xprt_free(xprt);
921 	module_put(THIS_MODULE);
922 }
923 
924 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
925 {
926 	struct xdr_skb_reader desc = {
927 		.skb		= skb,
928 		.offset		= sizeof(rpc_fraghdr),
929 		.count		= skb->len - sizeof(rpc_fraghdr),
930 	};
931 
932 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
933 		return -1;
934 	if (desc.count)
935 		return -1;
936 	return 0;
937 }
938 
939 /**
940  * xs_local_data_read_skb
941  * @xprt: transport
942  * @sk: socket
943  * @skb: skbuff
944  *
945  * Currently this assumes we can read the whole reply in a single gulp.
946  */
947 static void xs_local_data_read_skb(struct rpc_xprt *xprt,
948 		struct sock *sk,
949 		struct sk_buff *skb)
950 {
951 	struct rpc_task *task;
952 	struct rpc_rqst *rovr;
953 	int repsize, copied;
954 	u32 _xid;
955 	__be32 *xp;
956 
957 	repsize = skb->len - sizeof(rpc_fraghdr);
958 	if (repsize < 4) {
959 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
960 		return;
961 	}
962 
963 	/* Copy the XID from the skb... */
964 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
965 	if (xp == NULL)
966 		return;
967 
968 	/* Look up and lock the request corresponding to the given XID */
969 	spin_lock(&xprt->recv_lock);
970 	rovr = xprt_lookup_rqst(xprt, *xp);
971 	if (!rovr)
972 		goto out_unlock;
973 	xprt_pin_rqst(rovr);
974 	spin_unlock(&xprt->recv_lock);
975 	task = rovr->rq_task;
976 
977 	copied = rovr->rq_private_buf.buflen;
978 	if (copied > repsize)
979 		copied = repsize;
980 
981 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
982 		dprintk("RPC:       sk_buff copy failed\n");
983 		spin_lock(&xprt->recv_lock);
984 		goto out_unpin;
985 	}
986 
987 	spin_lock(&xprt->recv_lock);
988 	xprt_complete_rqst(task, copied);
989 out_unpin:
990 	xprt_unpin_rqst(rovr);
991  out_unlock:
992 	spin_unlock(&xprt->recv_lock);
993 }
994 
995 static void xs_local_data_receive(struct sock_xprt *transport)
996 {
997 	struct sk_buff *skb;
998 	struct sock *sk;
999 	int err;
1000 
1001 restart:
1002 	mutex_lock(&transport->recv_mutex);
1003 	sk = transport->inet;
1004 	if (sk == NULL)
1005 		goto out;
1006 	for (;;) {
1007 		skb = skb_recv_datagram(sk, 0, 1, &err);
1008 		if (skb != NULL) {
1009 			xs_local_data_read_skb(&transport->xprt, sk, skb);
1010 			skb_free_datagram(sk, skb);
1011 			continue;
1012 		}
1013 		if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1014 			break;
1015 		if (need_resched()) {
1016 			mutex_unlock(&transport->recv_mutex);
1017 			cond_resched();
1018 			goto restart;
1019 		}
1020 	}
1021 out:
1022 	mutex_unlock(&transport->recv_mutex);
1023 }
1024 
1025 static void xs_local_data_receive_workfn(struct work_struct *work)
1026 {
1027 	struct sock_xprt *transport =
1028 		container_of(work, struct sock_xprt, recv_worker);
1029 	xs_local_data_receive(transport);
1030 }
1031 
1032 /**
1033  * xs_udp_data_read_skb - receive callback for UDP sockets
1034  * @xprt: transport
1035  * @sk: socket
1036  * @skb: skbuff
1037  *
1038  */
1039 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1040 		struct sock *sk,
1041 		struct sk_buff *skb)
1042 {
1043 	struct rpc_task *task;
1044 	struct rpc_rqst *rovr;
1045 	int repsize, copied;
1046 	u32 _xid;
1047 	__be32 *xp;
1048 
1049 	repsize = skb->len;
1050 	if (repsize < 4) {
1051 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1052 		return;
1053 	}
1054 
1055 	/* Copy the XID from the skb... */
1056 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1057 	if (xp == NULL)
1058 		return;
1059 
1060 	/* Look up and lock the request corresponding to the given XID */
1061 	spin_lock(&xprt->recv_lock);
1062 	rovr = xprt_lookup_rqst(xprt, *xp);
1063 	if (!rovr)
1064 		goto out_unlock;
1065 	xprt_pin_rqst(rovr);
1066 	xprt_update_rtt(rovr->rq_task);
1067 	spin_unlock(&xprt->recv_lock);
1068 	task = rovr->rq_task;
1069 
1070 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1071 		copied = repsize;
1072 
1073 	/* Suck it into the iovec, verify checksum if not done by hw. */
1074 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1075 		spin_lock(&xprt->recv_lock);
1076 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1077 		goto out_unpin;
1078 	}
1079 
1080 
1081 	spin_lock_bh(&xprt->transport_lock);
1082 	xprt_adjust_cwnd(xprt, task, copied);
1083 	spin_unlock_bh(&xprt->transport_lock);
1084 	spin_lock(&xprt->recv_lock);
1085 	xprt_complete_rqst(task, copied);
1086 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1087 out_unpin:
1088 	xprt_unpin_rqst(rovr);
1089  out_unlock:
1090 	spin_unlock(&xprt->recv_lock);
1091 }
1092 
1093 static void xs_udp_data_receive(struct sock_xprt *transport)
1094 {
1095 	struct sk_buff *skb;
1096 	struct sock *sk;
1097 	int err;
1098 
1099 restart:
1100 	mutex_lock(&transport->recv_mutex);
1101 	sk = transport->inet;
1102 	if (sk == NULL)
1103 		goto out;
1104 	for (;;) {
1105 		skb = skb_recv_udp(sk, 0, 1, &err);
1106 		if (skb != NULL) {
1107 			xs_udp_data_read_skb(&transport->xprt, sk, skb);
1108 			consume_skb(skb);
1109 			continue;
1110 		}
1111 		if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1112 			break;
1113 		if (need_resched()) {
1114 			mutex_unlock(&transport->recv_mutex);
1115 			cond_resched();
1116 			goto restart;
1117 		}
1118 	}
1119 out:
1120 	mutex_unlock(&transport->recv_mutex);
1121 }
1122 
1123 static void xs_udp_data_receive_workfn(struct work_struct *work)
1124 {
1125 	struct sock_xprt *transport =
1126 		container_of(work, struct sock_xprt, recv_worker);
1127 	xs_udp_data_receive(transport);
1128 }
1129 
1130 /**
1131  * xs_data_ready - "data ready" callback for UDP sockets
1132  * @sk: socket with data to read
1133  *
1134  */
1135 static void xs_data_ready(struct sock *sk)
1136 {
1137 	struct rpc_xprt *xprt;
1138 
1139 	read_lock_bh(&sk->sk_callback_lock);
1140 	dprintk("RPC:       xs_data_ready...\n");
1141 	xprt = xprt_from_sock(sk);
1142 	if (xprt != NULL) {
1143 		struct sock_xprt *transport = container_of(xprt,
1144 				struct sock_xprt, xprt);
1145 		transport->old_data_ready(sk);
1146 		/* Any data means we had a useful conversation, so
1147 		 * then we don't need to delay the next reconnect
1148 		 */
1149 		if (xprt->reestablish_timeout)
1150 			xprt->reestablish_timeout = 0;
1151 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1152 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1153 	}
1154 	read_unlock_bh(&sk->sk_callback_lock);
1155 }
1156 
1157 /*
1158  * Helper function to force a TCP close if the server is sending
1159  * junk and/or it has put us in CLOSE_WAIT
1160  */
1161 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1162 {
1163 	xprt_force_disconnect(xprt);
1164 }
1165 
1166 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1167 {
1168 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1169 	size_t len, used;
1170 	char *p;
1171 
1172 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1173 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1174 	used = xdr_skb_read_bits(desc, p, len);
1175 	transport->tcp_offset += used;
1176 	if (used != len)
1177 		return;
1178 
1179 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1180 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1181 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1182 	else
1183 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1184 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1185 
1186 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1187 	transport->tcp_offset = 0;
1188 
1189 	/* Sanity check of the record length */
1190 	if (unlikely(transport->tcp_reclen < 8)) {
1191 		dprintk("RPC:       invalid TCP record fragment length\n");
1192 		xs_tcp_force_close(xprt);
1193 		return;
1194 	}
1195 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1196 			transport->tcp_reclen);
1197 }
1198 
1199 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1200 {
1201 	if (transport->tcp_offset == transport->tcp_reclen) {
1202 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1203 		transport->tcp_offset = 0;
1204 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1205 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1206 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1207 			transport->tcp_copied = 0;
1208 		}
1209 	}
1210 }
1211 
1212 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1213 {
1214 	size_t len, used;
1215 	char *p;
1216 
1217 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1218 	dprintk("RPC:       reading XID (%zu bytes)\n", len);
1219 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1220 	used = xdr_skb_read_bits(desc, p, len);
1221 	transport->tcp_offset += used;
1222 	if (used != len)
1223 		return;
1224 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1225 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1226 	transport->tcp_copied = 4;
1227 	dprintk("RPC:       reading %s XID %08x\n",
1228 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1229 							      : "request with",
1230 			ntohl(transport->tcp_xid));
1231 	xs_tcp_check_fraghdr(transport);
1232 }
1233 
1234 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1235 				       struct xdr_skb_reader *desc)
1236 {
1237 	size_t len, used;
1238 	u32 offset;
1239 	char *p;
1240 
1241 	/*
1242 	 * We want transport->tcp_offset to be 8 at the end of this routine
1243 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1244 	 * When this function is called for the first time,
1245 	 * transport->tcp_offset is 4 (after having already read the xid).
1246 	 */
1247 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1248 	len = sizeof(transport->tcp_calldir) - offset;
1249 	dprintk("RPC:       reading CALL/REPLY flag (%zu bytes)\n", len);
1250 	p = ((char *) &transport->tcp_calldir) + offset;
1251 	used = xdr_skb_read_bits(desc, p, len);
1252 	transport->tcp_offset += used;
1253 	if (used != len)
1254 		return;
1255 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1256 	/*
1257 	 * We don't yet have the XDR buffer, so we will write the calldir
1258 	 * out after we get the buffer from the 'struct rpc_rqst'
1259 	 */
1260 	switch (ntohl(transport->tcp_calldir)) {
1261 	case RPC_REPLY:
1262 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1263 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1264 		transport->tcp_flags |= TCP_RPC_REPLY;
1265 		break;
1266 	case RPC_CALL:
1267 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1268 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1269 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1270 		break;
1271 	default:
1272 		dprintk("RPC:       invalid request message type\n");
1273 		xs_tcp_force_close(&transport->xprt);
1274 	}
1275 	xs_tcp_check_fraghdr(transport);
1276 }
1277 
1278 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1279 				     struct xdr_skb_reader *desc,
1280 				     struct rpc_rqst *req)
1281 {
1282 	struct sock_xprt *transport =
1283 				container_of(xprt, struct sock_xprt, xprt);
1284 	struct xdr_buf *rcvbuf;
1285 	size_t len;
1286 	ssize_t r;
1287 
1288 	rcvbuf = &req->rq_private_buf;
1289 
1290 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1291 		/*
1292 		 * Save the RPC direction in the XDR buffer
1293 		 */
1294 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1295 			&transport->tcp_calldir,
1296 			sizeof(transport->tcp_calldir));
1297 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1298 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1299 	}
1300 
1301 	len = desc->count;
1302 	if (len > transport->tcp_reclen - transport->tcp_offset)
1303 		desc->count = transport->tcp_reclen - transport->tcp_offset;
1304 	r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1305 					  desc, xdr_skb_read_bits);
1306 
1307 	if (desc->count) {
1308 		/* Error when copying to the receive buffer,
1309 		 * usually because we weren't able to allocate
1310 		 * additional buffer pages. All we can do now
1311 		 * is turn off TCP_RCV_COPY_DATA, so the request
1312 		 * will not receive any additional updates,
1313 		 * and time out.
1314 		 * Any remaining data from this record will
1315 		 * be discarded.
1316 		 */
1317 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1318 		dprintk("RPC:       XID %08x truncated request\n",
1319 				ntohl(transport->tcp_xid));
1320 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1321 				"tcp_offset = %u, tcp_reclen = %u\n",
1322 				xprt, transport->tcp_copied,
1323 				transport->tcp_offset, transport->tcp_reclen);
1324 		return;
1325 	}
1326 
1327 	transport->tcp_copied += r;
1328 	transport->tcp_offset += r;
1329 	desc->count = len - r;
1330 
1331 	dprintk("RPC:       XID %08x read %zd bytes\n",
1332 			ntohl(transport->tcp_xid), r);
1333 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1334 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1335 			transport->tcp_offset, transport->tcp_reclen);
1336 
1337 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1338 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1339 	else if (transport->tcp_offset == transport->tcp_reclen) {
1340 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1341 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1342 	}
1343 }
1344 
1345 /*
1346  * Finds the request corresponding to the RPC xid and invokes the common
1347  * tcp read code to read the data.
1348  */
1349 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1350 				    struct xdr_skb_reader *desc)
1351 {
1352 	struct sock_xprt *transport =
1353 				container_of(xprt, struct sock_xprt, xprt);
1354 	struct rpc_rqst *req;
1355 
1356 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1357 
1358 	/* Find and lock the request corresponding to this xid */
1359 	spin_lock(&xprt->recv_lock);
1360 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1361 	if (!req) {
1362 		dprintk("RPC:       XID %08x request not found!\n",
1363 				ntohl(transport->tcp_xid));
1364 		spin_unlock(&xprt->recv_lock);
1365 		return -1;
1366 	}
1367 	xprt_pin_rqst(req);
1368 	spin_unlock(&xprt->recv_lock);
1369 
1370 	xs_tcp_read_common(xprt, desc, req);
1371 
1372 	spin_lock(&xprt->recv_lock);
1373 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1374 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1375 	xprt_unpin_rqst(req);
1376 	spin_unlock(&xprt->recv_lock);
1377 	return 0;
1378 }
1379 
1380 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1381 /*
1382  * Obtains an rpc_rqst previously allocated and invokes the common
1383  * tcp read code to read the data.  The result is placed in the callback
1384  * queue.
1385  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1386  * connection and return -1.
1387  */
1388 static int xs_tcp_read_callback(struct rpc_xprt *xprt,
1389 				       struct xdr_skb_reader *desc)
1390 {
1391 	struct sock_xprt *transport =
1392 				container_of(xprt, struct sock_xprt, xprt);
1393 	struct rpc_rqst *req;
1394 
1395 	/* Look up the request corresponding to the given XID */
1396 	req = xprt_lookup_bc_request(xprt, transport->tcp_xid);
1397 	if (req == NULL) {
1398 		printk(KERN_WARNING "Callback slot table overflowed\n");
1399 		xprt_force_disconnect(xprt);
1400 		return -1;
1401 	}
1402 
1403 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1404 	xs_tcp_read_common(xprt, desc, req);
1405 
1406 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1407 		xprt_complete_bc_request(req, transport->tcp_copied);
1408 
1409 	return 0;
1410 }
1411 
1412 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1413 					struct xdr_skb_reader *desc)
1414 {
1415 	struct sock_xprt *transport =
1416 				container_of(xprt, struct sock_xprt, xprt);
1417 
1418 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1419 		xs_tcp_read_reply(xprt, desc) :
1420 		xs_tcp_read_callback(xprt, desc);
1421 }
1422 
1423 static int xs_tcp_bc_up(struct svc_serv *serv, struct net *net)
1424 {
1425 	int ret;
1426 
1427 	ret = svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
1428 			      SVC_SOCK_ANONYMOUS);
1429 	if (ret < 0)
1430 		return ret;
1431 	return 0;
1432 }
1433 
1434 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1435 {
1436 	return PAGE_SIZE;
1437 }
1438 #else
1439 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1440 					struct xdr_skb_reader *desc)
1441 {
1442 	return xs_tcp_read_reply(xprt, desc);
1443 }
1444 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1445 
1446 /*
1447  * Read data off the transport.  This can be either an RPC_CALL or an
1448  * RPC_REPLY.  Relay the processing to helper functions.
1449  */
1450 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1451 				    struct xdr_skb_reader *desc)
1452 {
1453 	struct sock_xprt *transport =
1454 				container_of(xprt, struct sock_xprt, xprt);
1455 
1456 	if (_xs_tcp_read_data(xprt, desc) == 0)
1457 		xs_tcp_check_fraghdr(transport);
1458 	else {
1459 		/*
1460 		 * The transport_lock protects the request handling.
1461 		 * There's no need to hold it to update the tcp_flags.
1462 		 */
1463 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1464 	}
1465 }
1466 
1467 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1468 {
1469 	size_t len;
1470 
1471 	len = transport->tcp_reclen - transport->tcp_offset;
1472 	if (len > desc->count)
1473 		len = desc->count;
1474 	desc->count -= len;
1475 	desc->offset += len;
1476 	transport->tcp_offset += len;
1477 	dprintk("RPC:       discarded %zu bytes\n", len);
1478 	xs_tcp_check_fraghdr(transport);
1479 }
1480 
1481 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1482 {
1483 	struct rpc_xprt *xprt = rd_desc->arg.data;
1484 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1485 	struct xdr_skb_reader desc = {
1486 		.skb	= skb,
1487 		.offset	= offset,
1488 		.count	= len,
1489 	};
1490 	size_t ret;
1491 
1492 	dprintk("RPC:       xs_tcp_data_recv started\n");
1493 	do {
1494 		trace_xs_tcp_data_recv(transport);
1495 		/* Read in a new fragment marker if necessary */
1496 		/* Can we ever really expect to get completely empty fragments? */
1497 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1498 			xs_tcp_read_fraghdr(xprt, &desc);
1499 			continue;
1500 		}
1501 		/* Read in the xid if necessary */
1502 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1503 			xs_tcp_read_xid(transport, &desc);
1504 			continue;
1505 		}
1506 		/* Read in the call/reply flag */
1507 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1508 			xs_tcp_read_calldir(transport, &desc);
1509 			continue;
1510 		}
1511 		/* Read in the request data */
1512 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1513 			xs_tcp_read_data(xprt, &desc);
1514 			continue;
1515 		}
1516 		/* Skip over any trailing bytes on short reads */
1517 		xs_tcp_read_discard(transport, &desc);
1518 	} while (desc.count);
1519 	ret = len - desc.count;
1520 	if (ret < rd_desc->count)
1521 		rd_desc->count -= ret;
1522 	else
1523 		rd_desc->count = 0;
1524 	trace_xs_tcp_data_recv(transport);
1525 	dprintk("RPC:       xs_tcp_data_recv done\n");
1526 	return ret;
1527 }
1528 
1529 static void xs_tcp_data_receive(struct sock_xprt *transport)
1530 {
1531 	struct rpc_xprt *xprt = &transport->xprt;
1532 	struct sock *sk;
1533 	read_descriptor_t rd_desc = {
1534 		.arg.data = xprt,
1535 	};
1536 	unsigned long total = 0;
1537 	int read = 0;
1538 
1539 restart:
1540 	mutex_lock(&transport->recv_mutex);
1541 	sk = transport->inet;
1542 	if (sk == NULL)
1543 		goto out;
1544 
1545 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1546 	for (;;) {
1547 		rd_desc.count = RPC_TCP_READ_CHUNK_SZ;
1548 		lock_sock(sk);
1549 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1550 		if (rd_desc.count != 0 || read < 0) {
1551 			clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1552 			release_sock(sk);
1553 			break;
1554 		}
1555 		release_sock(sk);
1556 		total += read;
1557 		if (need_resched()) {
1558 			mutex_unlock(&transport->recv_mutex);
1559 			cond_resched();
1560 			goto restart;
1561 		}
1562 	}
1563 	if (test_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1564 		queue_work(xprtiod_workqueue, &transport->recv_worker);
1565 out:
1566 	mutex_unlock(&transport->recv_mutex);
1567 	trace_xs_tcp_data_ready(xprt, read, total);
1568 }
1569 
1570 static void xs_tcp_data_receive_workfn(struct work_struct *work)
1571 {
1572 	struct sock_xprt *transport =
1573 		container_of(work, struct sock_xprt, recv_worker);
1574 	xs_tcp_data_receive(transport);
1575 }
1576 
1577 /**
1578  * xs_tcp_state_change - callback to handle TCP socket state changes
1579  * @sk: socket whose state has changed
1580  *
1581  */
1582 static void xs_tcp_state_change(struct sock *sk)
1583 {
1584 	struct rpc_xprt *xprt;
1585 	struct sock_xprt *transport;
1586 
1587 	read_lock_bh(&sk->sk_callback_lock);
1588 	if (!(xprt = xprt_from_sock(sk)))
1589 		goto out;
1590 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1591 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1592 			sk->sk_state, xprt_connected(xprt),
1593 			sock_flag(sk, SOCK_DEAD),
1594 			sock_flag(sk, SOCK_ZAPPED),
1595 			sk->sk_shutdown);
1596 
1597 	transport = container_of(xprt, struct sock_xprt, xprt);
1598 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1599 	switch (sk->sk_state) {
1600 	case TCP_ESTABLISHED:
1601 		spin_lock(&xprt->transport_lock);
1602 		if (!xprt_test_and_set_connected(xprt)) {
1603 
1604 			/* Reset TCP record info */
1605 			transport->tcp_offset = 0;
1606 			transport->tcp_reclen = 0;
1607 			transport->tcp_copied = 0;
1608 			transport->tcp_flags =
1609 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1610 			xprt->connect_cookie++;
1611 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1612 			xprt_clear_connecting(xprt);
1613 
1614 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1615 		}
1616 		spin_unlock(&xprt->transport_lock);
1617 		break;
1618 	case TCP_FIN_WAIT1:
1619 		/* The client initiated a shutdown of the socket */
1620 		xprt->connect_cookie++;
1621 		xprt->reestablish_timeout = 0;
1622 		set_bit(XPRT_CLOSING, &xprt->state);
1623 		smp_mb__before_atomic();
1624 		clear_bit(XPRT_CONNECTED, &xprt->state);
1625 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1626 		smp_mb__after_atomic();
1627 		break;
1628 	case TCP_CLOSE_WAIT:
1629 		/* The server initiated a shutdown of the socket */
1630 		xprt->connect_cookie++;
1631 		clear_bit(XPRT_CONNECTED, &xprt->state);
1632 		xs_tcp_force_close(xprt);
1633 		/* fall through */
1634 	case TCP_CLOSING:
1635 		/*
1636 		 * If the server closed down the connection, make sure that
1637 		 * we back off before reconnecting
1638 		 */
1639 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1640 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1641 		break;
1642 	case TCP_LAST_ACK:
1643 		set_bit(XPRT_CLOSING, &xprt->state);
1644 		smp_mb__before_atomic();
1645 		clear_bit(XPRT_CONNECTED, &xprt->state);
1646 		smp_mb__after_atomic();
1647 		break;
1648 	case TCP_CLOSE:
1649 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1650 					&transport->sock_state))
1651 			xprt_clear_connecting(xprt);
1652 		clear_bit(XPRT_CLOSING, &xprt->state);
1653 		if (sk->sk_err)
1654 			xprt_wake_pending_tasks(xprt, -sk->sk_err);
1655 		/* Trigger the socket release */
1656 		xs_tcp_force_close(xprt);
1657 	}
1658  out:
1659 	read_unlock_bh(&sk->sk_callback_lock);
1660 }
1661 
1662 static void xs_write_space(struct sock *sk)
1663 {
1664 	struct socket_wq *wq;
1665 	struct rpc_xprt *xprt;
1666 
1667 	if (!sk->sk_socket)
1668 		return;
1669 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1670 
1671 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1672 		return;
1673 	rcu_read_lock();
1674 	wq = rcu_dereference(sk->sk_wq);
1675 	if (!wq || test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags) == 0)
1676 		goto out;
1677 
1678 	xprt_write_space(xprt);
1679 out:
1680 	rcu_read_unlock();
1681 }
1682 
1683 /**
1684  * xs_udp_write_space - callback invoked when socket buffer space
1685  *                             becomes available
1686  * @sk: socket whose state has changed
1687  *
1688  * Called when more output buffer space is available for this socket.
1689  * We try not to wake our writers until they can make "significant"
1690  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1691  * with a bunch of small requests.
1692  */
1693 static void xs_udp_write_space(struct sock *sk)
1694 {
1695 	read_lock_bh(&sk->sk_callback_lock);
1696 
1697 	/* from net/core/sock.c:sock_def_write_space */
1698 	if (sock_writeable(sk))
1699 		xs_write_space(sk);
1700 
1701 	read_unlock_bh(&sk->sk_callback_lock);
1702 }
1703 
1704 /**
1705  * xs_tcp_write_space - callback invoked when socket buffer space
1706  *                             becomes available
1707  * @sk: socket whose state has changed
1708  *
1709  * Called when more output buffer space is available for this socket.
1710  * We try not to wake our writers until they can make "significant"
1711  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1712  * with a bunch of small requests.
1713  */
1714 static void xs_tcp_write_space(struct sock *sk)
1715 {
1716 	read_lock_bh(&sk->sk_callback_lock);
1717 
1718 	/* from net/core/stream.c:sk_stream_write_space */
1719 	if (sk_stream_is_writeable(sk))
1720 		xs_write_space(sk);
1721 
1722 	read_unlock_bh(&sk->sk_callback_lock);
1723 }
1724 
1725 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1726 {
1727 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1728 	struct sock *sk = transport->inet;
1729 
1730 	if (transport->rcvsize) {
1731 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1732 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1733 	}
1734 	if (transport->sndsize) {
1735 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1736 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1737 		sk->sk_write_space(sk);
1738 	}
1739 }
1740 
1741 /**
1742  * xs_udp_set_buffer_size - set send and receive limits
1743  * @xprt: generic transport
1744  * @sndsize: requested size of send buffer, in bytes
1745  * @rcvsize: requested size of receive buffer, in bytes
1746  *
1747  * Set socket send and receive buffer size limits.
1748  */
1749 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1750 {
1751 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1752 
1753 	transport->sndsize = 0;
1754 	if (sndsize)
1755 		transport->sndsize = sndsize + 1024;
1756 	transport->rcvsize = 0;
1757 	if (rcvsize)
1758 		transport->rcvsize = rcvsize + 1024;
1759 
1760 	xs_udp_do_set_buffer_size(xprt);
1761 }
1762 
1763 /**
1764  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1765  * @task: task that timed out
1766  *
1767  * Adjust the congestion window after a retransmit timeout has occurred.
1768  */
1769 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1770 {
1771 	spin_lock_bh(&xprt->transport_lock);
1772 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1773 	spin_unlock_bh(&xprt->transport_lock);
1774 }
1775 
1776 static unsigned short xs_get_random_port(void)
1777 {
1778 	unsigned short range = xprt_max_resvport - xprt_min_resvport + 1;
1779 	unsigned short rand = (unsigned short) prandom_u32() % range;
1780 	return rand + xprt_min_resvport;
1781 }
1782 
1783 /**
1784  * xs_set_reuseaddr_port - set the socket's port and address reuse options
1785  * @sock: socket
1786  *
1787  * Note that this function has to be called on all sockets that share the
1788  * same port, and it must be called before binding.
1789  */
1790 static void xs_sock_set_reuseport(struct socket *sock)
1791 {
1792 	int opt = 1;
1793 
1794 	kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
1795 			(char *)&opt, sizeof(opt));
1796 }
1797 
1798 static unsigned short xs_sock_getport(struct socket *sock)
1799 {
1800 	struct sockaddr_storage buf;
1801 	unsigned short port = 0;
1802 
1803 	if (kernel_getsockname(sock, (struct sockaddr *)&buf) < 0)
1804 		goto out;
1805 	switch (buf.ss_family) {
1806 	case AF_INET6:
1807 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1808 		break;
1809 	case AF_INET:
1810 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1811 	}
1812 out:
1813 	return port;
1814 }
1815 
1816 /**
1817  * xs_set_port - reset the port number in the remote endpoint address
1818  * @xprt: generic transport
1819  * @port: new port number
1820  *
1821  */
1822 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1823 {
1824 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1825 
1826 	rpc_set_port(xs_addr(xprt), port);
1827 	xs_update_peer_port(xprt);
1828 }
1829 
1830 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1831 {
1832 	if (transport->srcport == 0)
1833 		transport->srcport = xs_sock_getport(sock);
1834 }
1835 
1836 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1837 {
1838 	unsigned short port = transport->srcport;
1839 
1840 	if (port == 0 && transport->xprt.resvport)
1841 		port = xs_get_random_port();
1842 	return port;
1843 }
1844 
1845 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1846 {
1847 	if (transport->srcport != 0)
1848 		transport->srcport = 0;
1849 	if (!transport->xprt.resvport)
1850 		return 0;
1851 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1852 		return xprt_max_resvport;
1853 	return --port;
1854 }
1855 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1856 {
1857 	struct sockaddr_storage myaddr;
1858 	int err, nloop = 0;
1859 	unsigned short port = xs_get_srcport(transport);
1860 	unsigned short last;
1861 
1862 	/*
1863 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1864 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1865 	 * port selection happen implicitly when the socket is used
1866 	 * (for example at connect time).
1867 	 *
1868 	 * This ensures that we can continue to establish TCP
1869 	 * connections even when all local ephemeral ports are already
1870 	 * a part of some TCP connection.  This makes no difference
1871 	 * for UDP sockets, but also doens't harm them.
1872 	 *
1873 	 * If we're asking for any reserved port (i.e. port == 0 &&
1874 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1875 	 * ensure that port is non-zero and we will bind as needed.
1876 	 */
1877 	if (port == 0)
1878 		return 0;
1879 
1880 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1881 	do {
1882 		rpc_set_port((struct sockaddr *)&myaddr, port);
1883 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1884 				transport->xprt.addrlen);
1885 		if (err == 0) {
1886 			transport->srcport = port;
1887 			break;
1888 		}
1889 		last = port;
1890 		port = xs_next_srcport(transport, port);
1891 		if (port > last)
1892 			nloop++;
1893 	} while (err == -EADDRINUSE && nloop != 2);
1894 
1895 	if (myaddr.ss_family == AF_INET)
1896 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1897 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1898 				port, err ? "failed" : "ok", err);
1899 	else
1900 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1901 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1902 				port, err ? "failed" : "ok", err);
1903 	return err;
1904 }
1905 
1906 /*
1907  * We don't support autobind on AF_LOCAL sockets
1908  */
1909 static void xs_local_rpcbind(struct rpc_task *task)
1910 {
1911 	xprt_set_bound(task->tk_xprt);
1912 }
1913 
1914 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1915 {
1916 }
1917 
1918 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1919 static struct lock_class_key xs_key[2];
1920 static struct lock_class_key xs_slock_key[2];
1921 
1922 static inline void xs_reclassify_socketu(struct socket *sock)
1923 {
1924 	struct sock *sk = sock->sk;
1925 
1926 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1927 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1928 }
1929 
1930 static inline void xs_reclassify_socket4(struct socket *sock)
1931 {
1932 	struct sock *sk = sock->sk;
1933 
1934 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1935 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1936 }
1937 
1938 static inline void xs_reclassify_socket6(struct socket *sock)
1939 {
1940 	struct sock *sk = sock->sk;
1941 
1942 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1943 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1944 }
1945 
1946 static inline void xs_reclassify_socket(int family, struct socket *sock)
1947 {
1948 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1949 		return;
1950 
1951 	switch (family) {
1952 	case AF_LOCAL:
1953 		xs_reclassify_socketu(sock);
1954 		break;
1955 	case AF_INET:
1956 		xs_reclassify_socket4(sock);
1957 		break;
1958 	case AF_INET6:
1959 		xs_reclassify_socket6(sock);
1960 		break;
1961 	}
1962 }
1963 #else
1964 static inline void xs_reclassify_socket(int family, struct socket *sock)
1965 {
1966 }
1967 #endif
1968 
1969 static void xs_dummy_setup_socket(struct work_struct *work)
1970 {
1971 }
1972 
1973 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1974 		struct sock_xprt *transport, int family, int type,
1975 		int protocol, bool reuseport)
1976 {
1977 	struct socket *sock;
1978 	int err;
1979 
1980 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1981 	if (err < 0) {
1982 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1983 				protocol, -err);
1984 		goto out;
1985 	}
1986 	xs_reclassify_socket(family, sock);
1987 
1988 	if (reuseport)
1989 		xs_sock_set_reuseport(sock);
1990 
1991 	err = xs_bind(transport, sock);
1992 	if (err) {
1993 		sock_release(sock);
1994 		goto out;
1995 	}
1996 
1997 	return sock;
1998 out:
1999 	return ERR_PTR(err);
2000 }
2001 
2002 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
2003 				      struct socket *sock)
2004 {
2005 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2006 									xprt);
2007 
2008 	if (!transport->inet) {
2009 		struct sock *sk = sock->sk;
2010 
2011 		write_lock_bh(&sk->sk_callback_lock);
2012 
2013 		xs_save_old_callbacks(transport, sk);
2014 
2015 		sk->sk_user_data = xprt;
2016 		sk->sk_data_ready = xs_data_ready;
2017 		sk->sk_write_space = xs_udp_write_space;
2018 		sock_set_flag(sk, SOCK_FASYNC);
2019 		sk->sk_error_report = xs_error_report;
2020 		sk->sk_allocation = GFP_NOIO;
2021 
2022 		xprt_clear_connected(xprt);
2023 
2024 		/* Reset to new socket */
2025 		transport->sock = sock;
2026 		transport->inet = sk;
2027 
2028 		write_unlock_bh(&sk->sk_callback_lock);
2029 	}
2030 
2031 	/* Tell the socket layer to start connecting... */
2032 	xprt->stat.connect_count++;
2033 	xprt->stat.connect_start = jiffies;
2034 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
2035 }
2036 
2037 /**
2038  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
2039  * @transport: socket transport to connect
2040  */
2041 static int xs_local_setup_socket(struct sock_xprt *transport)
2042 {
2043 	struct rpc_xprt *xprt = &transport->xprt;
2044 	struct socket *sock;
2045 	int status = -EIO;
2046 
2047 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
2048 					SOCK_STREAM, 0, &sock, 1);
2049 	if (status < 0) {
2050 		dprintk("RPC:       can't create AF_LOCAL "
2051 			"transport socket (%d).\n", -status);
2052 		goto out;
2053 	}
2054 	xs_reclassify_socket(AF_LOCAL, sock);
2055 
2056 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
2057 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2058 
2059 	status = xs_local_finish_connecting(xprt, sock);
2060 	trace_rpc_socket_connect(xprt, sock, status);
2061 	switch (status) {
2062 	case 0:
2063 		dprintk("RPC:       xprt %p connected to %s\n",
2064 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2065 		xprt_set_connected(xprt);
2066 	case -ENOBUFS:
2067 		break;
2068 	case -ENOENT:
2069 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
2070 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2071 		break;
2072 	case -ECONNREFUSED:
2073 		dprintk("RPC:       xprt %p: connection refused for %s\n",
2074 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2075 		break;
2076 	default:
2077 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
2078 				__func__, -status,
2079 				xprt->address_strings[RPC_DISPLAY_ADDR]);
2080 	}
2081 
2082 out:
2083 	xprt_clear_connecting(xprt);
2084 	xprt_wake_pending_tasks(xprt, status);
2085 	return status;
2086 }
2087 
2088 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2089 {
2090 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2091 	int ret;
2092 
2093 	 if (RPC_IS_ASYNC(task)) {
2094 		/*
2095 		 * We want the AF_LOCAL connect to be resolved in the
2096 		 * filesystem namespace of the process making the rpc
2097 		 * call.  Thus we connect synchronously.
2098 		 *
2099 		 * If we want to support asynchronous AF_LOCAL calls,
2100 		 * we'll need to figure out how to pass a namespace to
2101 		 * connect.
2102 		 */
2103 		rpc_exit(task, -ENOTCONN);
2104 		return;
2105 	}
2106 	ret = xs_local_setup_socket(transport);
2107 	if (ret && !RPC_IS_SOFTCONN(task))
2108 		msleep_interruptible(15000);
2109 }
2110 
2111 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2112 /*
2113  * Note that this should be called with XPRT_LOCKED held (or when we otherwise
2114  * know that we have exclusive access to the socket), to guard against
2115  * races with xs_reset_transport.
2116  */
2117 static void xs_set_memalloc(struct rpc_xprt *xprt)
2118 {
2119 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2120 			xprt);
2121 
2122 	/*
2123 	 * If there's no sock, then we have nothing to set. The
2124 	 * reconnecting process will get it for us.
2125 	 */
2126 	if (!transport->inet)
2127 		return;
2128 	if (atomic_read(&xprt->swapper))
2129 		sk_set_memalloc(transport->inet);
2130 }
2131 
2132 /**
2133  * xs_enable_swap - Tag this transport as being used for swap.
2134  * @xprt: transport to tag
2135  *
2136  * Take a reference to this transport on behalf of the rpc_clnt, and
2137  * optionally mark it for swapping if it wasn't already.
2138  */
2139 static int
2140 xs_enable_swap(struct rpc_xprt *xprt)
2141 {
2142 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2143 
2144 	if (atomic_inc_return(&xprt->swapper) != 1)
2145 		return 0;
2146 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2147 		return -ERESTARTSYS;
2148 	if (xs->inet)
2149 		sk_set_memalloc(xs->inet);
2150 	xprt_release_xprt(xprt, NULL);
2151 	return 0;
2152 }
2153 
2154 /**
2155  * xs_disable_swap - Untag this transport as being used for swap.
2156  * @xprt: transport to tag
2157  *
2158  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2159  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2160  */
2161 static void
2162 xs_disable_swap(struct rpc_xprt *xprt)
2163 {
2164 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2165 
2166 	if (!atomic_dec_and_test(&xprt->swapper))
2167 		return;
2168 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2169 		return;
2170 	if (xs->inet)
2171 		sk_clear_memalloc(xs->inet);
2172 	xprt_release_xprt(xprt, NULL);
2173 }
2174 #else
2175 static void xs_set_memalloc(struct rpc_xprt *xprt)
2176 {
2177 }
2178 
2179 static int
2180 xs_enable_swap(struct rpc_xprt *xprt)
2181 {
2182 	return -EINVAL;
2183 }
2184 
2185 static void
2186 xs_disable_swap(struct rpc_xprt *xprt)
2187 {
2188 }
2189 #endif
2190 
2191 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2192 {
2193 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2194 
2195 	if (!transport->inet) {
2196 		struct sock *sk = sock->sk;
2197 
2198 		write_lock_bh(&sk->sk_callback_lock);
2199 
2200 		xs_save_old_callbacks(transport, sk);
2201 
2202 		sk->sk_user_data = xprt;
2203 		sk->sk_data_ready = xs_data_ready;
2204 		sk->sk_write_space = xs_udp_write_space;
2205 		sock_set_flag(sk, SOCK_FASYNC);
2206 		sk->sk_allocation = GFP_NOIO;
2207 
2208 		xprt_set_connected(xprt);
2209 
2210 		/* Reset to new socket */
2211 		transport->sock = sock;
2212 		transport->inet = sk;
2213 
2214 		xs_set_memalloc(xprt);
2215 
2216 		write_unlock_bh(&sk->sk_callback_lock);
2217 	}
2218 	xs_udp_do_set_buffer_size(xprt);
2219 
2220 	xprt->stat.connect_start = jiffies;
2221 }
2222 
2223 static void xs_udp_setup_socket(struct work_struct *work)
2224 {
2225 	struct sock_xprt *transport =
2226 		container_of(work, struct sock_xprt, connect_worker.work);
2227 	struct rpc_xprt *xprt = &transport->xprt;
2228 	struct socket *sock;
2229 	int status = -EIO;
2230 
2231 	sock = xs_create_sock(xprt, transport,
2232 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2233 			IPPROTO_UDP, false);
2234 	if (IS_ERR(sock))
2235 		goto out;
2236 
2237 	dprintk("RPC:       worker connecting xprt %p via %s to "
2238 				"%s (port %s)\n", xprt,
2239 			xprt->address_strings[RPC_DISPLAY_PROTO],
2240 			xprt->address_strings[RPC_DISPLAY_ADDR],
2241 			xprt->address_strings[RPC_DISPLAY_PORT]);
2242 
2243 	xs_udp_finish_connecting(xprt, sock);
2244 	trace_rpc_socket_connect(xprt, sock, 0);
2245 	status = 0;
2246 out:
2247 	xprt_unlock_connect(xprt, transport);
2248 	xprt_clear_connecting(xprt);
2249 	xprt_wake_pending_tasks(xprt, status);
2250 }
2251 
2252 /**
2253  * xs_tcp_shutdown - gracefully shut down a TCP socket
2254  * @xprt: transport
2255  *
2256  * Initiates a graceful shutdown of the TCP socket by calling the
2257  * equivalent of shutdown(SHUT_RDWR);
2258  */
2259 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2260 {
2261 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2262 	struct socket *sock = transport->sock;
2263 	int skst = transport->inet ? transport->inet->sk_state : TCP_CLOSE;
2264 
2265 	if (sock == NULL)
2266 		return;
2267 	switch (skst) {
2268 	default:
2269 		kernel_sock_shutdown(sock, SHUT_RDWR);
2270 		trace_rpc_socket_shutdown(xprt, sock);
2271 		break;
2272 	case TCP_CLOSE:
2273 	case TCP_TIME_WAIT:
2274 		xs_reset_transport(transport);
2275 	}
2276 }
2277 
2278 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2279 		struct socket *sock)
2280 {
2281 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2282 	unsigned int keepidle;
2283 	unsigned int keepcnt;
2284 	unsigned int opt_on = 1;
2285 	unsigned int timeo;
2286 
2287 	spin_lock_bh(&xprt->transport_lock);
2288 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2289 	keepcnt = xprt->timeout->to_retries + 1;
2290 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2291 		(xprt->timeout->to_retries + 1);
2292 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2293 	spin_unlock_bh(&xprt->transport_lock);
2294 
2295 	/* TCP Keepalive options */
2296 	kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
2297 			(char *)&opt_on, sizeof(opt_on));
2298 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
2299 			(char *)&keepidle, sizeof(keepidle));
2300 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
2301 			(char *)&keepidle, sizeof(keepidle));
2302 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
2303 			(char *)&keepcnt, sizeof(keepcnt));
2304 
2305 	/* TCP user timeout (see RFC5482) */
2306 	kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
2307 			(char *)&timeo, sizeof(timeo));
2308 }
2309 
2310 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2311 		unsigned long connect_timeout,
2312 		unsigned long reconnect_timeout)
2313 {
2314 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2315 	struct rpc_timeout to;
2316 	unsigned long initval;
2317 
2318 	spin_lock_bh(&xprt->transport_lock);
2319 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2320 		xprt->max_reconnect_timeout = reconnect_timeout;
2321 	if (connect_timeout < xprt->connect_timeout) {
2322 		memcpy(&to, xprt->timeout, sizeof(to));
2323 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2324 		/* Arbitrary lower limit */
2325 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2326 			initval = XS_TCP_INIT_REEST_TO << 1;
2327 		to.to_initval = initval;
2328 		to.to_maxval = initval;
2329 		memcpy(&transport->tcp_timeout, &to,
2330 				sizeof(transport->tcp_timeout));
2331 		xprt->timeout = &transport->tcp_timeout;
2332 		xprt->connect_timeout = connect_timeout;
2333 	}
2334 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2335 	spin_unlock_bh(&xprt->transport_lock);
2336 }
2337 
2338 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2339 {
2340 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2341 	int ret = -ENOTCONN;
2342 
2343 	if (!transport->inet) {
2344 		struct sock *sk = sock->sk;
2345 		unsigned int addr_pref = IPV6_PREFER_SRC_PUBLIC;
2346 
2347 		/* Avoid temporary address, they are bad for long-lived
2348 		 * connections such as NFS mounts.
2349 		 * RFC4941, section 3.6 suggests that:
2350 		 *    Individual applications, which have specific
2351 		 *    knowledge about the normal duration of connections,
2352 		 *    MAY override this as appropriate.
2353 		 */
2354 		kernel_setsockopt(sock, SOL_IPV6, IPV6_ADDR_PREFERENCES,
2355 				(char *)&addr_pref, sizeof(addr_pref));
2356 
2357 		xs_tcp_set_socket_timeouts(xprt, sock);
2358 
2359 		write_lock_bh(&sk->sk_callback_lock);
2360 
2361 		xs_save_old_callbacks(transport, sk);
2362 
2363 		sk->sk_user_data = xprt;
2364 		sk->sk_data_ready = xs_data_ready;
2365 		sk->sk_state_change = xs_tcp_state_change;
2366 		sk->sk_write_space = xs_tcp_write_space;
2367 		sock_set_flag(sk, SOCK_FASYNC);
2368 		sk->sk_error_report = xs_error_report;
2369 		sk->sk_allocation = GFP_NOIO;
2370 
2371 		/* socket options */
2372 		sock_reset_flag(sk, SOCK_LINGER);
2373 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2374 
2375 		xprt_clear_connected(xprt);
2376 
2377 		/* Reset to new socket */
2378 		transport->sock = sock;
2379 		transport->inet = sk;
2380 
2381 		write_unlock_bh(&sk->sk_callback_lock);
2382 	}
2383 
2384 	if (!xprt_bound(xprt))
2385 		goto out;
2386 
2387 	xs_set_memalloc(xprt);
2388 
2389 	/* Tell the socket layer to start connecting... */
2390 	xprt->stat.connect_count++;
2391 	xprt->stat.connect_start = jiffies;
2392 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2393 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2394 	switch (ret) {
2395 	case 0:
2396 		xs_set_srcport(transport, sock);
2397 		/* fall through */
2398 	case -EINPROGRESS:
2399 		/* SYN_SENT! */
2400 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2401 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2402 		break;
2403 	case -EADDRNOTAVAIL:
2404 		/* Source port number is unavailable. Try a new one! */
2405 		transport->srcport = 0;
2406 	}
2407 out:
2408 	return ret;
2409 }
2410 
2411 /**
2412  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2413  *
2414  * Invoked by a work queue tasklet.
2415  */
2416 static void xs_tcp_setup_socket(struct work_struct *work)
2417 {
2418 	struct sock_xprt *transport =
2419 		container_of(work, struct sock_xprt, connect_worker.work);
2420 	struct socket *sock = transport->sock;
2421 	struct rpc_xprt *xprt = &transport->xprt;
2422 	int status = -EIO;
2423 
2424 	if (!sock) {
2425 		sock = xs_create_sock(xprt, transport,
2426 				xs_addr(xprt)->sa_family, SOCK_STREAM,
2427 				IPPROTO_TCP, true);
2428 		if (IS_ERR(sock)) {
2429 			status = PTR_ERR(sock);
2430 			goto out;
2431 		}
2432 	}
2433 
2434 	dprintk("RPC:       worker connecting xprt %p via %s to "
2435 				"%s (port %s)\n", xprt,
2436 			xprt->address_strings[RPC_DISPLAY_PROTO],
2437 			xprt->address_strings[RPC_DISPLAY_ADDR],
2438 			xprt->address_strings[RPC_DISPLAY_PORT]);
2439 
2440 	status = xs_tcp_finish_connecting(xprt, sock);
2441 	trace_rpc_socket_connect(xprt, sock, status);
2442 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2443 			xprt, -status, xprt_connected(xprt),
2444 			sock->sk->sk_state);
2445 	switch (status) {
2446 	default:
2447 		printk("%s: connect returned unhandled error %d\n",
2448 			__func__, status);
2449 		/* fall through */
2450 	case -EADDRNOTAVAIL:
2451 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2452 		 * and retry
2453 		 */
2454 		xs_tcp_force_close(xprt);
2455 		break;
2456 	case 0:
2457 	case -EINPROGRESS:
2458 	case -EALREADY:
2459 		xprt_unlock_connect(xprt, transport);
2460 		return;
2461 	case -EINVAL:
2462 		/* Happens, for instance, if the user specified a link
2463 		 * local IPv6 address without a scope-id.
2464 		 */
2465 	case -ECONNREFUSED:
2466 	case -ECONNRESET:
2467 	case -ENETDOWN:
2468 	case -ENETUNREACH:
2469 	case -EHOSTUNREACH:
2470 	case -EADDRINUSE:
2471 	case -ENOBUFS:
2472 		/*
2473 		 * xs_tcp_force_close() wakes tasks with -EIO.
2474 		 * We need to wake them first to ensure the
2475 		 * correct error code.
2476 		 */
2477 		xprt_wake_pending_tasks(xprt, status);
2478 		xs_tcp_force_close(xprt);
2479 		goto out;
2480 	}
2481 	status = -EAGAIN;
2482 out:
2483 	xprt_unlock_connect(xprt, transport);
2484 	xprt_clear_connecting(xprt);
2485 	xprt_wake_pending_tasks(xprt, status);
2486 }
2487 
2488 static unsigned long xs_reconnect_delay(const struct rpc_xprt *xprt)
2489 {
2490 	unsigned long start, now = jiffies;
2491 
2492 	start = xprt->stat.connect_start + xprt->reestablish_timeout;
2493 	if (time_after(start, now))
2494 		return start - now;
2495 	return 0;
2496 }
2497 
2498 static void xs_reconnect_backoff(struct rpc_xprt *xprt)
2499 {
2500 	xprt->reestablish_timeout <<= 1;
2501 	if (xprt->reestablish_timeout > xprt->max_reconnect_timeout)
2502 		xprt->reestablish_timeout = xprt->max_reconnect_timeout;
2503 	if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2504 		xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2505 }
2506 
2507 /**
2508  * xs_connect - connect a socket to a remote endpoint
2509  * @xprt: pointer to transport structure
2510  * @task: address of RPC task that manages state of connect request
2511  *
2512  * TCP: If the remote end dropped the connection, delay reconnecting.
2513  *
2514  * UDP socket connects are synchronous, but we use a work queue anyway
2515  * to guarantee that even unprivileged user processes can set up a
2516  * socket on a privileged port.
2517  *
2518  * If a UDP socket connect fails, the delay behavior here prevents
2519  * retry floods (hard mounts).
2520  */
2521 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2522 {
2523 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2524 	unsigned long delay = 0;
2525 
2526 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2527 
2528 	if (transport->sock != NULL) {
2529 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2530 				"seconds\n",
2531 				xprt, xprt->reestablish_timeout / HZ);
2532 
2533 		/* Start by resetting any existing state */
2534 		xs_reset_transport(transport);
2535 
2536 		delay = xs_reconnect_delay(xprt);
2537 		xs_reconnect_backoff(xprt);
2538 
2539 	} else
2540 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2541 
2542 	queue_delayed_work(xprtiod_workqueue,
2543 			&transport->connect_worker,
2544 			delay);
2545 }
2546 
2547 /**
2548  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2549  * @xprt: rpc_xprt struct containing statistics
2550  * @seq: output file
2551  *
2552  */
2553 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2554 {
2555 	long idle_time = 0;
2556 
2557 	if (xprt_connected(xprt))
2558 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2559 
2560 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2561 			"%llu %llu %lu %llu %llu\n",
2562 			xprt->stat.bind_count,
2563 			xprt->stat.connect_count,
2564 			xprt->stat.connect_time,
2565 			idle_time,
2566 			xprt->stat.sends,
2567 			xprt->stat.recvs,
2568 			xprt->stat.bad_xids,
2569 			xprt->stat.req_u,
2570 			xprt->stat.bklog_u,
2571 			xprt->stat.max_slots,
2572 			xprt->stat.sending_u,
2573 			xprt->stat.pending_u);
2574 }
2575 
2576 /**
2577  * xs_udp_print_stats - display UDP socket-specifc stats
2578  * @xprt: rpc_xprt struct containing statistics
2579  * @seq: output file
2580  *
2581  */
2582 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2583 {
2584 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2585 
2586 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2587 			"%lu %llu %llu\n",
2588 			transport->srcport,
2589 			xprt->stat.bind_count,
2590 			xprt->stat.sends,
2591 			xprt->stat.recvs,
2592 			xprt->stat.bad_xids,
2593 			xprt->stat.req_u,
2594 			xprt->stat.bklog_u,
2595 			xprt->stat.max_slots,
2596 			xprt->stat.sending_u,
2597 			xprt->stat.pending_u);
2598 }
2599 
2600 /**
2601  * xs_tcp_print_stats - display TCP socket-specifc stats
2602  * @xprt: rpc_xprt struct containing statistics
2603  * @seq: output file
2604  *
2605  */
2606 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2607 {
2608 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2609 	long idle_time = 0;
2610 
2611 	if (xprt_connected(xprt))
2612 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2613 
2614 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2615 			"%llu %llu %lu %llu %llu\n",
2616 			transport->srcport,
2617 			xprt->stat.bind_count,
2618 			xprt->stat.connect_count,
2619 			xprt->stat.connect_time,
2620 			idle_time,
2621 			xprt->stat.sends,
2622 			xprt->stat.recvs,
2623 			xprt->stat.bad_xids,
2624 			xprt->stat.req_u,
2625 			xprt->stat.bklog_u,
2626 			xprt->stat.max_slots,
2627 			xprt->stat.sending_u,
2628 			xprt->stat.pending_u);
2629 }
2630 
2631 /*
2632  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2633  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2634  * to use the server side send routines.
2635  */
2636 static int bc_malloc(struct rpc_task *task)
2637 {
2638 	struct rpc_rqst *rqst = task->tk_rqstp;
2639 	size_t size = rqst->rq_callsize;
2640 	struct page *page;
2641 	struct rpc_buffer *buf;
2642 
2643 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2644 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2645 			  size);
2646 		return -EINVAL;
2647 	}
2648 
2649 	page = alloc_page(GFP_KERNEL);
2650 	if (!page)
2651 		return -ENOMEM;
2652 
2653 	buf = page_address(page);
2654 	buf->len = PAGE_SIZE;
2655 
2656 	rqst->rq_buffer = buf->data;
2657 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2658 	return 0;
2659 }
2660 
2661 /*
2662  * Free the space allocated in the bc_alloc routine
2663  */
2664 static void bc_free(struct rpc_task *task)
2665 {
2666 	void *buffer = task->tk_rqstp->rq_buffer;
2667 	struct rpc_buffer *buf;
2668 
2669 	buf = container_of(buffer, struct rpc_buffer, data);
2670 	free_page((unsigned long)buf);
2671 }
2672 
2673 /*
2674  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2675  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2676  */
2677 static int bc_sendto(struct rpc_rqst *req)
2678 {
2679 	int len;
2680 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2681 	struct rpc_xprt *xprt = req->rq_xprt;
2682 	struct sock_xprt *transport =
2683 				container_of(xprt, struct sock_xprt, xprt);
2684 	struct socket *sock = transport->sock;
2685 	unsigned long headoff;
2686 	unsigned long tailoff;
2687 
2688 	xs_encode_stream_record_marker(xbufp);
2689 
2690 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2691 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2692 	len = svc_send_common(sock, xbufp,
2693 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2694 			      xbufp->tail[0].iov_base, tailoff);
2695 
2696 	if (len != xbufp->len) {
2697 		printk(KERN_NOTICE "Error sending entire callback!\n");
2698 		len = -EAGAIN;
2699 	}
2700 
2701 	return len;
2702 }
2703 
2704 /*
2705  * The send routine. Borrows from svc_send
2706  */
2707 static int bc_send_request(struct rpc_task *task)
2708 {
2709 	struct rpc_rqst *req = task->tk_rqstp;
2710 	struct svc_xprt	*xprt;
2711 	int len;
2712 
2713 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2714 	/*
2715 	 * Get the server socket associated with this callback xprt
2716 	 */
2717 	xprt = req->rq_xprt->bc_xprt;
2718 
2719 	/*
2720 	 * Grab the mutex to serialize data as the connection is shared
2721 	 * with the fore channel
2722 	 */
2723 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2724 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2725 		if (!mutex_trylock(&xprt->xpt_mutex))
2726 			return -EAGAIN;
2727 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2728 	}
2729 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2730 		len = -ENOTCONN;
2731 	else
2732 		len = bc_sendto(req);
2733 	mutex_unlock(&xprt->xpt_mutex);
2734 
2735 	if (len > 0)
2736 		len = 0;
2737 
2738 	return len;
2739 }
2740 
2741 /*
2742  * The close routine. Since this is client initiated, we do nothing
2743  */
2744 
2745 static void bc_close(struct rpc_xprt *xprt)
2746 {
2747 }
2748 
2749 /*
2750  * The xprt destroy routine. Again, because this connection is client
2751  * initiated, we do nothing
2752  */
2753 
2754 static void bc_destroy(struct rpc_xprt *xprt)
2755 {
2756 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2757 
2758 	xs_xprt_free(xprt);
2759 	module_put(THIS_MODULE);
2760 }
2761 
2762 static const struct rpc_xprt_ops xs_local_ops = {
2763 	.reserve_xprt		= xprt_reserve_xprt,
2764 	.release_xprt		= xs_tcp_release_xprt,
2765 	.alloc_slot		= xprt_alloc_slot,
2766 	.free_slot		= xprt_free_slot,
2767 	.rpcbind		= xs_local_rpcbind,
2768 	.set_port		= xs_local_set_port,
2769 	.connect		= xs_local_connect,
2770 	.buf_alloc		= rpc_malloc,
2771 	.buf_free		= rpc_free,
2772 	.send_request		= xs_local_send_request,
2773 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2774 	.close			= xs_close,
2775 	.destroy		= xs_destroy,
2776 	.print_stats		= xs_local_print_stats,
2777 	.enable_swap		= xs_enable_swap,
2778 	.disable_swap		= xs_disable_swap,
2779 };
2780 
2781 static const struct rpc_xprt_ops xs_udp_ops = {
2782 	.set_buffer_size	= xs_udp_set_buffer_size,
2783 	.reserve_xprt		= xprt_reserve_xprt_cong,
2784 	.release_xprt		= xprt_release_xprt_cong,
2785 	.alloc_slot		= xprt_alloc_slot,
2786 	.free_slot		= xprt_free_slot,
2787 	.rpcbind		= rpcb_getport_async,
2788 	.set_port		= xs_set_port,
2789 	.connect		= xs_connect,
2790 	.buf_alloc		= rpc_malloc,
2791 	.buf_free		= rpc_free,
2792 	.send_request		= xs_udp_send_request,
2793 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2794 	.timer			= xs_udp_timer,
2795 	.release_request	= xprt_release_rqst_cong,
2796 	.close			= xs_close,
2797 	.destroy		= xs_destroy,
2798 	.print_stats		= xs_udp_print_stats,
2799 	.enable_swap		= xs_enable_swap,
2800 	.disable_swap		= xs_disable_swap,
2801 	.inject_disconnect	= xs_inject_disconnect,
2802 };
2803 
2804 static const struct rpc_xprt_ops xs_tcp_ops = {
2805 	.reserve_xprt		= xprt_reserve_xprt,
2806 	.release_xprt		= xs_tcp_release_xprt,
2807 	.alloc_slot		= xprt_lock_and_alloc_slot,
2808 	.free_slot		= xprt_free_slot,
2809 	.rpcbind		= rpcb_getport_async,
2810 	.set_port		= xs_set_port,
2811 	.connect		= xs_connect,
2812 	.buf_alloc		= rpc_malloc,
2813 	.buf_free		= rpc_free,
2814 	.send_request		= xs_tcp_send_request,
2815 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2816 	.close			= xs_tcp_shutdown,
2817 	.destroy		= xs_destroy,
2818 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2819 	.print_stats		= xs_tcp_print_stats,
2820 	.enable_swap		= xs_enable_swap,
2821 	.disable_swap		= xs_disable_swap,
2822 	.inject_disconnect	= xs_inject_disconnect,
2823 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2824 	.bc_setup		= xprt_setup_bc,
2825 	.bc_up			= xs_tcp_bc_up,
2826 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2827 	.bc_free_rqst		= xprt_free_bc_rqst,
2828 	.bc_destroy		= xprt_destroy_bc,
2829 #endif
2830 };
2831 
2832 /*
2833  * The rpc_xprt_ops for the server backchannel
2834  */
2835 
2836 static const struct rpc_xprt_ops bc_tcp_ops = {
2837 	.reserve_xprt		= xprt_reserve_xprt,
2838 	.release_xprt		= xprt_release_xprt,
2839 	.alloc_slot		= xprt_alloc_slot,
2840 	.free_slot		= xprt_free_slot,
2841 	.buf_alloc		= bc_malloc,
2842 	.buf_free		= bc_free,
2843 	.send_request		= bc_send_request,
2844 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2845 	.close			= bc_close,
2846 	.destroy		= bc_destroy,
2847 	.print_stats		= xs_tcp_print_stats,
2848 	.enable_swap		= xs_enable_swap,
2849 	.disable_swap		= xs_disable_swap,
2850 	.inject_disconnect	= xs_inject_disconnect,
2851 };
2852 
2853 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2854 {
2855 	static const struct sockaddr_in sin = {
2856 		.sin_family		= AF_INET,
2857 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2858 	};
2859 	static const struct sockaddr_in6 sin6 = {
2860 		.sin6_family		= AF_INET6,
2861 		.sin6_addr		= IN6ADDR_ANY_INIT,
2862 	};
2863 
2864 	switch (family) {
2865 	case AF_LOCAL:
2866 		break;
2867 	case AF_INET:
2868 		memcpy(sap, &sin, sizeof(sin));
2869 		break;
2870 	case AF_INET6:
2871 		memcpy(sap, &sin6, sizeof(sin6));
2872 		break;
2873 	default:
2874 		dprintk("RPC:       %s: Bad address family\n", __func__);
2875 		return -EAFNOSUPPORT;
2876 	}
2877 	return 0;
2878 }
2879 
2880 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2881 				      unsigned int slot_table_size,
2882 				      unsigned int max_slot_table_size)
2883 {
2884 	struct rpc_xprt *xprt;
2885 	struct sock_xprt *new;
2886 
2887 	if (args->addrlen > sizeof(xprt->addr)) {
2888 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2889 		return ERR_PTR(-EBADF);
2890 	}
2891 
2892 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2893 			max_slot_table_size);
2894 	if (xprt == NULL) {
2895 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2896 				"rpc_xprt\n");
2897 		return ERR_PTR(-ENOMEM);
2898 	}
2899 
2900 	new = container_of(xprt, struct sock_xprt, xprt);
2901 	mutex_init(&new->recv_mutex);
2902 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2903 	xprt->addrlen = args->addrlen;
2904 	if (args->srcaddr)
2905 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2906 	else {
2907 		int err;
2908 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2909 					(struct sockaddr *)&new->srcaddr);
2910 		if (err != 0) {
2911 			xprt_free(xprt);
2912 			return ERR_PTR(err);
2913 		}
2914 	}
2915 
2916 	return xprt;
2917 }
2918 
2919 static const struct rpc_timeout xs_local_default_timeout = {
2920 	.to_initval = 10 * HZ,
2921 	.to_maxval = 10 * HZ,
2922 	.to_retries = 2,
2923 };
2924 
2925 /**
2926  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2927  * @args: rpc transport creation arguments
2928  *
2929  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2930  */
2931 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2932 {
2933 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2934 	struct sock_xprt *transport;
2935 	struct rpc_xprt *xprt;
2936 	struct rpc_xprt *ret;
2937 
2938 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2939 			xprt_max_tcp_slot_table_entries);
2940 	if (IS_ERR(xprt))
2941 		return xprt;
2942 	transport = container_of(xprt, struct sock_xprt, xprt);
2943 
2944 	xprt->prot = 0;
2945 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2946 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2947 
2948 	xprt->bind_timeout = XS_BIND_TO;
2949 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2950 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2951 
2952 	xprt->ops = &xs_local_ops;
2953 	xprt->timeout = &xs_local_default_timeout;
2954 
2955 	INIT_WORK(&transport->recv_worker, xs_local_data_receive_workfn);
2956 	INIT_DELAYED_WORK(&transport->connect_worker,
2957 			xs_dummy_setup_socket);
2958 
2959 	switch (sun->sun_family) {
2960 	case AF_LOCAL:
2961 		if (sun->sun_path[0] != '/') {
2962 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2963 					sun->sun_path);
2964 			ret = ERR_PTR(-EINVAL);
2965 			goto out_err;
2966 		}
2967 		xprt_set_bound(xprt);
2968 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2969 		ret = ERR_PTR(xs_local_setup_socket(transport));
2970 		if (ret)
2971 			goto out_err;
2972 		break;
2973 	default:
2974 		ret = ERR_PTR(-EAFNOSUPPORT);
2975 		goto out_err;
2976 	}
2977 
2978 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2979 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2980 
2981 	if (try_module_get(THIS_MODULE))
2982 		return xprt;
2983 	ret = ERR_PTR(-EINVAL);
2984 out_err:
2985 	xs_xprt_free(xprt);
2986 	return ret;
2987 }
2988 
2989 static const struct rpc_timeout xs_udp_default_timeout = {
2990 	.to_initval = 5 * HZ,
2991 	.to_maxval = 30 * HZ,
2992 	.to_increment = 5 * HZ,
2993 	.to_retries = 5,
2994 };
2995 
2996 /**
2997  * xs_setup_udp - Set up transport to use a UDP socket
2998  * @args: rpc transport creation arguments
2999  *
3000  */
3001 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
3002 {
3003 	struct sockaddr *addr = args->dstaddr;
3004 	struct rpc_xprt *xprt;
3005 	struct sock_xprt *transport;
3006 	struct rpc_xprt *ret;
3007 
3008 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
3009 			xprt_udp_slot_table_entries);
3010 	if (IS_ERR(xprt))
3011 		return xprt;
3012 	transport = container_of(xprt, struct sock_xprt, xprt);
3013 
3014 	xprt->prot = IPPROTO_UDP;
3015 	xprt->tsh_size = 0;
3016 	/* XXX: header size can vary due to auth type, IPv6, etc. */
3017 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
3018 
3019 	xprt->bind_timeout = XS_BIND_TO;
3020 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
3021 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3022 
3023 	xprt->ops = &xs_udp_ops;
3024 
3025 	xprt->timeout = &xs_udp_default_timeout;
3026 
3027 	INIT_WORK(&transport->recv_worker, xs_udp_data_receive_workfn);
3028 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
3029 
3030 	switch (addr->sa_family) {
3031 	case AF_INET:
3032 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3033 			xprt_set_bound(xprt);
3034 
3035 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
3036 		break;
3037 	case AF_INET6:
3038 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3039 			xprt_set_bound(xprt);
3040 
3041 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
3042 		break;
3043 	default:
3044 		ret = ERR_PTR(-EAFNOSUPPORT);
3045 		goto out_err;
3046 	}
3047 
3048 	if (xprt_bound(xprt))
3049 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3050 				xprt->address_strings[RPC_DISPLAY_ADDR],
3051 				xprt->address_strings[RPC_DISPLAY_PORT],
3052 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3053 	else
3054 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3055 				xprt->address_strings[RPC_DISPLAY_ADDR],
3056 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3057 
3058 	if (try_module_get(THIS_MODULE))
3059 		return xprt;
3060 	ret = ERR_PTR(-EINVAL);
3061 out_err:
3062 	xs_xprt_free(xprt);
3063 	return ret;
3064 }
3065 
3066 static const struct rpc_timeout xs_tcp_default_timeout = {
3067 	.to_initval = 60 * HZ,
3068 	.to_maxval = 60 * HZ,
3069 	.to_retries = 2,
3070 };
3071 
3072 /**
3073  * xs_setup_tcp - Set up transport to use a TCP socket
3074  * @args: rpc transport creation arguments
3075  *
3076  */
3077 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
3078 {
3079 	struct sockaddr *addr = args->dstaddr;
3080 	struct rpc_xprt *xprt;
3081 	struct sock_xprt *transport;
3082 	struct rpc_xprt *ret;
3083 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
3084 
3085 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
3086 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
3087 
3088 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3089 			max_slot_table_size);
3090 	if (IS_ERR(xprt))
3091 		return xprt;
3092 	transport = container_of(xprt, struct sock_xprt, xprt);
3093 
3094 	xprt->prot = IPPROTO_TCP;
3095 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
3096 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3097 
3098 	xprt->bind_timeout = XS_BIND_TO;
3099 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
3100 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3101 
3102 	xprt->ops = &xs_tcp_ops;
3103 	xprt->timeout = &xs_tcp_default_timeout;
3104 
3105 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3106 	xprt->connect_timeout = xprt->timeout->to_initval *
3107 		(xprt->timeout->to_retries + 1);
3108 
3109 	INIT_WORK(&transport->recv_worker, xs_tcp_data_receive_workfn);
3110 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3111 
3112 	switch (addr->sa_family) {
3113 	case AF_INET:
3114 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3115 			xprt_set_bound(xprt);
3116 
3117 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3118 		break;
3119 	case AF_INET6:
3120 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3121 			xprt_set_bound(xprt);
3122 
3123 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3124 		break;
3125 	default:
3126 		ret = ERR_PTR(-EAFNOSUPPORT);
3127 		goto out_err;
3128 	}
3129 
3130 	if (xprt_bound(xprt))
3131 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3132 				xprt->address_strings[RPC_DISPLAY_ADDR],
3133 				xprt->address_strings[RPC_DISPLAY_PORT],
3134 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3135 	else
3136 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3137 				xprt->address_strings[RPC_DISPLAY_ADDR],
3138 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3139 
3140 	if (try_module_get(THIS_MODULE))
3141 		return xprt;
3142 	ret = ERR_PTR(-EINVAL);
3143 out_err:
3144 	xs_xprt_free(xprt);
3145 	return ret;
3146 }
3147 
3148 /**
3149  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3150  * @args: rpc transport creation arguments
3151  *
3152  */
3153 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3154 {
3155 	struct sockaddr *addr = args->dstaddr;
3156 	struct rpc_xprt *xprt;
3157 	struct sock_xprt *transport;
3158 	struct svc_sock *bc_sock;
3159 	struct rpc_xprt *ret;
3160 
3161 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3162 			xprt_tcp_slot_table_entries);
3163 	if (IS_ERR(xprt))
3164 		return xprt;
3165 	transport = container_of(xprt, struct sock_xprt, xprt);
3166 
3167 	xprt->prot = IPPROTO_TCP;
3168 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
3169 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3170 	xprt->timeout = &xs_tcp_default_timeout;
3171 
3172 	/* backchannel */
3173 	xprt_set_bound(xprt);
3174 	xprt->bind_timeout = 0;
3175 	xprt->reestablish_timeout = 0;
3176 	xprt->idle_timeout = 0;
3177 
3178 	xprt->ops = &bc_tcp_ops;
3179 
3180 	switch (addr->sa_family) {
3181 	case AF_INET:
3182 		xs_format_peer_addresses(xprt, "tcp",
3183 					 RPCBIND_NETID_TCP);
3184 		break;
3185 	case AF_INET6:
3186 		xs_format_peer_addresses(xprt, "tcp",
3187 				   RPCBIND_NETID_TCP6);
3188 		break;
3189 	default:
3190 		ret = ERR_PTR(-EAFNOSUPPORT);
3191 		goto out_err;
3192 	}
3193 
3194 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3195 			xprt->address_strings[RPC_DISPLAY_ADDR],
3196 			xprt->address_strings[RPC_DISPLAY_PORT],
3197 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3198 
3199 	/*
3200 	 * Once we've associated a backchannel xprt with a connection,
3201 	 * we want to keep it around as long as the connection lasts,
3202 	 * in case we need to start using it for a backchannel again;
3203 	 * this reference won't be dropped until bc_xprt is destroyed.
3204 	 */
3205 	xprt_get(xprt);
3206 	args->bc_xprt->xpt_bc_xprt = xprt;
3207 	xprt->bc_xprt = args->bc_xprt;
3208 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3209 	transport->sock = bc_sock->sk_sock;
3210 	transport->inet = bc_sock->sk_sk;
3211 
3212 	/*
3213 	 * Since we don't want connections for the backchannel, we set
3214 	 * the xprt status to connected
3215 	 */
3216 	xprt_set_connected(xprt);
3217 
3218 	if (try_module_get(THIS_MODULE))
3219 		return xprt;
3220 
3221 	args->bc_xprt->xpt_bc_xprt = NULL;
3222 	args->bc_xprt->xpt_bc_xps = NULL;
3223 	xprt_put(xprt);
3224 	ret = ERR_PTR(-EINVAL);
3225 out_err:
3226 	xs_xprt_free(xprt);
3227 	return ret;
3228 }
3229 
3230 static struct xprt_class	xs_local_transport = {
3231 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3232 	.name		= "named UNIX socket",
3233 	.owner		= THIS_MODULE,
3234 	.ident		= XPRT_TRANSPORT_LOCAL,
3235 	.setup		= xs_setup_local,
3236 };
3237 
3238 static struct xprt_class	xs_udp_transport = {
3239 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3240 	.name		= "udp",
3241 	.owner		= THIS_MODULE,
3242 	.ident		= XPRT_TRANSPORT_UDP,
3243 	.setup		= xs_setup_udp,
3244 };
3245 
3246 static struct xprt_class	xs_tcp_transport = {
3247 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3248 	.name		= "tcp",
3249 	.owner		= THIS_MODULE,
3250 	.ident		= XPRT_TRANSPORT_TCP,
3251 	.setup		= xs_setup_tcp,
3252 };
3253 
3254 static struct xprt_class	xs_bc_tcp_transport = {
3255 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3256 	.name		= "tcp NFSv4.1 backchannel",
3257 	.owner		= THIS_MODULE,
3258 	.ident		= XPRT_TRANSPORT_BC_TCP,
3259 	.setup		= xs_setup_bc_tcp,
3260 };
3261 
3262 /**
3263  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3264  *
3265  */
3266 int init_socket_xprt(void)
3267 {
3268 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3269 	if (!sunrpc_table_header)
3270 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
3271 #endif
3272 
3273 	xprt_register_transport(&xs_local_transport);
3274 	xprt_register_transport(&xs_udp_transport);
3275 	xprt_register_transport(&xs_tcp_transport);
3276 	xprt_register_transport(&xs_bc_tcp_transport);
3277 
3278 	return 0;
3279 }
3280 
3281 /**
3282  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3283  *
3284  */
3285 void cleanup_socket_xprt(void)
3286 {
3287 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3288 	if (sunrpc_table_header) {
3289 		unregister_sysctl_table(sunrpc_table_header);
3290 		sunrpc_table_header = NULL;
3291 	}
3292 #endif
3293 
3294 	xprt_unregister_transport(&xs_local_transport);
3295 	xprt_unregister_transport(&xs_udp_transport);
3296 	xprt_unregister_transport(&xs_tcp_transport);
3297 	xprt_unregister_transport(&xs_bc_tcp_transport);
3298 }
3299 
3300 static int param_set_uint_minmax(const char *val,
3301 		const struct kernel_param *kp,
3302 		unsigned int min, unsigned int max)
3303 {
3304 	unsigned int num;
3305 	int ret;
3306 
3307 	if (!val)
3308 		return -EINVAL;
3309 	ret = kstrtouint(val, 0, &num);
3310 	if (ret)
3311 		return ret;
3312 	if (num < min || num > max)
3313 		return -EINVAL;
3314 	*((unsigned int *)kp->arg) = num;
3315 	return 0;
3316 }
3317 
3318 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3319 {
3320 	if (kp->arg == &xprt_min_resvport)
3321 		return param_set_uint_minmax(val, kp,
3322 			RPC_MIN_RESVPORT,
3323 			xprt_max_resvport);
3324 	return param_set_uint_minmax(val, kp,
3325 			xprt_min_resvport,
3326 			RPC_MAX_RESVPORT);
3327 }
3328 
3329 static const struct kernel_param_ops param_ops_portnr = {
3330 	.set = param_set_portnr,
3331 	.get = param_get_uint,
3332 };
3333 
3334 #define param_check_portnr(name, p) \
3335 	__param_check(name, p, unsigned int);
3336 
3337 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3338 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3339 
3340 static int param_set_slot_table_size(const char *val,
3341 				     const struct kernel_param *kp)
3342 {
3343 	return param_set_uint_minmax(val, kp,
3344 			RPC_MIN_SLOT_TABLE,
3345 			RPC_MAX_SLOT_TABLE);
3346 }
3347 
3348 static const struct kernel_param_ops param_ops_slot_table_size = {
3349 	.set = param_set_slot_table_size,
3350 	.get = param_get_uint,
3351 };
3352 
3353 #define param_check_slot_table_size(name, p) \
3354 	__param_check(name, p, unsigned int);
3355 
3356 static int param_set_max_slot_table_size(const char *val,
3357 				     const struct kernel_param *kp)
3358 {
3359 	return param_set_uint_minmax(val, kp,
3360 			RPC_MIN_SLOT_TABLE,
3361 			RPC_MAX_SLOT_TABLE_LIMIT);
3362 }
3363 
3364 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3365 	.set = param_set_max_slot_table_size,
3366 	.get = param_get_uint,
3367 };
3368 
3369 #define param_check_max_slot_table_size(name, p) \
3370 	__param_check(name, p, unsigned int);
3371 
3372 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3373 		   slot_table_size, 0644);
3374 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3375 		   max_slot_table_size, 0644);
3376 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3377 		   slot_table_size, 0644);
3378 
3379