xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision b24413180f5600bcb3bb70fbed5cf186b60864bd)
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 static void xs_close(struct rpc_xprt *xprt);
56 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
57 		struct socket *sock);
58 
59 /*
60  * xprtsock tunables
61  */
62 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
63 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
64 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
65 
66 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
67 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
68 
69 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
70 
71 #define XS_TCP_LINGER_TO	(15U * HZ)
72 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
73 
74 /*
75  * We can register our own files under /proc/sys/sunrpc by
76  * calling register_sysctl_table() again.  The files in that
77  * directory become the union of all files registered there.
78  *
79  * We simply need to make sure that we don't collide with
80  * someone else's file names!
81  */
82 
83 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
84 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
85 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
86 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
87 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
88 
89 static struct ctl_table_header *sunrpc_table_header;
90 
91 /*
92  * FIXME: changing the UDP slot table size should also resize the UDP
93  *        socket buffers for existing UDP transports
94  */
95 static struct ctl_table xs_tunables_table[] = {
96 	{
97 		.procname	= "udp_slot_table_entries",
98 		.data		= &xprt_udp_slot_table_entries,
99 		.maxlen		= sizeof(unsigned int),
100 		.mode		= 0644,
101 		.proc_handler	= proc_dointvec_minmax,
102 		.extra1		= &min_slot_table_size,
103 		.extra2		= &max_slot_table_size
104 	},
105 	{
106 		.procname	= "tcp_slot_table_entries",
107 		.data		= &xprt_tcp_slot_table_entries,
108 		.maxlen		= sizeof(unsigned int),
109 		.mode		= 0644,
110 		.proc_handler	= proc_dointvec_minmax,
111 		.extra1		= &min_slot_table_size,
112 		.extra2		= &max_slot_table_size
113 	},
114 	{
115 		.procname	= "tcp_max_slot_table_entries",
116 		.data		= &xprt_max_tcp_slot_table_entries,
117 		.maxlen		= sizeof(unsigned int),
118 		.mode		= 0644,
119 		.proc_handler	= proc_dointvec_minmax,
120 		.extra1		= &min_slot_table_size,
121 		.extra2		= &max_tcp_slot_table_limit
122 	},
123 	{
124 		.procname	= "min_resvport",
125 		.data		= &xprt_min_resvport,
126 		.maxlen		= sizeof(unsigned int),
127 		.mode		= 0644,
128 		.proc_handler	= proc_dointvec_minmax,
129 		.extra1		= &xprt_min_resvport_limit,
130 		.extra2		= &xprt_max_resvport
131 	},
132 	{
133 		.procname	= "max_resvport",
134 		.data		= &xprt_max_resvport,
135 		.maxlen		= sizeof(unsigned int),
136 		.mode		= 0644,
137 		.proc_handler	= proc_dointvec_minmax,
138 		.extra1		= &xprt_min_resvport,
139 		.extra2		= &xprt_max_resvport_limit
140 	},
141 	{
142 		.procname	= "tcp_fin_timeout",
143 		.data		= &xs_tcp_fin_timeout,
144 		.maxlen		= sizeof(xs_tcp_fin_timeout),
145 		.mode		= 0644,
146 		.proc_handler	= proc_dointvec_jiffies,
147 	},
148 	{ },
149 };
150 
151 static struct ctl_table sunrpc_table[] = {
152 	{
153 		.procname	= "sunrpc",
154 		.mode		= 0555,
155 		.child		= xs_tunables_table
156 	},
157 	{ },
158 };
159 
160 #endif
161 
162 /*
163  * Wait duration for a reply from the RPC portmapper.
164  */
165 #define XS_BIND_TO		(60U * HZ)
166 
167 /*
168  * Delay if a UDP socket connect error occurs.  This is most likely some
169  * kind of resource problem on the local host.
170  */
171 #define XS_UDP_REEST_TO		(2U * HZ)
172 
173 /*
174  * The reestablish timeout allows clients to delay for a bit before attempting
175  * to reconnect to a server that just dropped our connection.
176  *
177  * We implement an exponential backoff when trying to reestablish a TCP
178  * transport connection with the server.  Some servers like to drop a TCP
179  * connection when they are overworked, so we start with a short timeout and
180  * increase over time if the server is down or not responding.
181  */
182 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
183 
184 /*
185  * TCP idle timeout; client drops the transport socket if it is idle
186  * for this long.  Note that we also timeout UDP sockets to prevent
187  * holding port numbers when there is no RPC traffic.
188  */
189 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
190 
191 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
192 # undef  RPC_DEBUG_DATA
193 # define RPCDBG_FACILITY	RPCDBG_TRANS
194 #endif
195 
196 #ifdef RPC_DEBUG_DATA
197 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
198 {
199 	u8 *buf = (u8 *) packet;
200 	int j;
201 
202 	dprintk("RPC:       %s\n", msg);
203 	for (j = 0; j < count && j < 128; j += 4) {
204 		if (!(j & 31)) {
205 			if (j)
206 				dprintk("\n");
207 			dprintk("0x%04x ", j);
208 		}
209 		dprintk("%02x%02x%02x%02x ",
210 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
211 	}
212 	dprintk("\n");
213 }
214 #else
215 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
216 {
217 	/* NOP */
218 }
219 #endif
220 
221 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
222 {
223 	return (struct rpc_xprt *) sk->sk_user_data;
224 }
225 
226 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
227 {
228 	return (struct sockaddr *) &xprt->addr;
229 }
230 
231 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
232 {
233 	return (struct sockaddr_un *) &xprt->addr;
234 }
235 
236 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
237 {
238 	return (struct sockaddr_in *) &xprt->addr;
239 }
240 
241 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
242 {
243 	return (struct sockaddr_in6 *) &xprt->addr;
244 }
245 
246 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
247 {
248 	struct sockaddr *sap = xs_addr(xprt);
249 	struct sockaddr_in6 *sin6;
250 	struct sockaddr_in *sin;
251 	struct sockaddr_un *sun;
252 	char buf[128];
253 
254 	switch (sap->sa_family) {
255 	case AF_LOCAL:
256 		sun = xs_addr_un(xprt);
257 		strlcpy(buf, sun->sun_path, sizeof(buf));
258 		xprt->address_strings[RPC_DISPLAY_ADDR] =
259 						kstrdup(buf, GFP_KERNEL);
260 		break;
261 	case AF_INET:
262 		(void)rpc_ntop(sap, buf, sizeof(buf));
263 		xprt->address_strings[RPC_DISPLAY_ADDR] =
264 						kstrdup(buf, GFP_KERNEL);
265 		sin = xs_addr_in(xprt);
266 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
267 		break;
268 	case AF_INET6:
269 		(void)rpc_ntop(sap, buf, sizeof(buf));
270 		xprt->address_strings[RPC_DISPLAY_ADDR] =
271 						kstrdup(buf, GFP_KERNEL);
272 		sin6 = xs_addr_in6(xprt);
273 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
274 		break;
275 	default:
276 		BUG();
277 	}
278 
279 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
280 }
281 
282 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
283 {
284 	struct sockaddr *sap = xs_addr(xprt);
285 	char buf[128];
286 
287 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
288 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
289 
290 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
291 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
292 }
293 
294 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
295 				     const char *protocol,
296 				     const char *netid)
297 {
298 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
299 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
300 	xs_format_common_peer_addresses(xprt);
301 	xs_format_common_peer_ports(xprt);
302 }
303 
304 static void xs_update_peer_port(struct rpc_xprt *xprt)
305 {
306 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
307 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
308 
309 	xs_format_common_peer_ports(xprt);
310 }
311 
312 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
313 {
314 	unsigned int i;
315 
316 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
317 		switch (i) {
318 		case RPC_DISPLAY_PROTO:
319 		case RPC_DISPLAY_NETID:
320 			continue;
321 		default:
322 			kfree(xprt->address_strings[i]);
323 		}
324 }
325 
326 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
327 
328 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
329 {
330 	struct msghdr msg = {
331 		.msg_name	= addr,
332 		.msg_namelen	= addrlen,
333 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
334 	};
335 	struct kvec iov = {
336 		.iov_base	= vec->iov_base + base,
337 		.iov_len	= vec->iov_len - base,
338 	};
339 
340 	if (iov.iov_len != 0)
341 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
342 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
343 }
344 
345 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
346 {
347 	ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
348 			int offset, size_t size, int flags);
349 	struct page **ppage;
350 	unsigned int remainder;
351 	int err;
352 
353 	remainder = xdr->page_len - base;
354 	base += xdr->page_base;
355 	ppage = xdr->pages + (base >> PAGE_SHIFT);
356 	base &= ~PAGE_MASK;
357 	do_sendpage = sock->ops->sendpage;
358 	if (!zerocopy)
359 		do_sendpage = sock_no_sendpage;
360 	for(;;) {
361 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
362 		int flags = XS_SENDMSG_FLAGS;
363 
364 		remainder -= len;
365 		if (more)
366 			flags |= MSG_MORE;
367 		if (remainder != 0)
368 			flags |= MSG_SENDPAGE_NOTLAST | MSG_MORE;
369 		err = do_sendpage(sock, *ppage, base, len, flags);
370 		if (remainder == 0 || err != len)
371 			break;
372 		*sent_p += err;
373 		ppage++;
374 		base = 0;
375 	}
376 	if (err > 0) {
377 		*sent_p += err;
378 		err = 0;
379 	}
380 	return err;
381 }
382 
383 /**
384  * xs_sendpages - write pages directly to a socket
385  * @sock: socket to send on
386  * @addr: UDP only -- address of destination
387  * @addrlen: UDP only -- length of destination address
388  * @xdr: buffer containing this request
389  * @base: starting position in the buffer
390  * @zerocopy: true if it is safe to use sendpage()
391  * @sent_p: return the total number of bytes successfully queued for sending
392  *
393  */
394 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
395 {
396 	unsigned int remainder = xdr->len - base;
397 	int err = 0;
398 	int sent = 0;
399 
400 	if (unlikely(!sock))
401 		return -ENOTSOCK;
402 
403 	if (base != 0) {
404 		addr = NULL;
405 		addrlen = 0;
406 	}
407 
408 	if (base < xdr->head[0].iov_len || addr != NULL) {
409 		unsigned int len = xdr->head[0].iov_len - base;
410 		remainder -= len;
411 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
412 		if (remainder == 0 || err != len)
413 			goto out;
414 		*sent_p += err;
415 		base = 0;
416 	} else
417 		base -= xdr->head[0].iov_len;
418 
419 	if (base < xdr->page_len) {
420 		unsigned int len = xdr->page_len - base;
421 		remainder -= len;
422 		err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
423 		*sent_p += sent;
424 		if (remainder == 0 || sent != len)
425 			goto out;
426 		base = 0;
427 	} else
428 		base -= xdr->page_len;
429 
430 	if (base >= xdr->tail[0].iov_len)
431 		return 0;
432 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
433 out:
434 	if (err > 0) {
435 		*sent_p += err;
436 		err = 0;
437 	}
438 	return err;
439 }
440 
441 static void xs_nospace_callback(struct rpc_task *task)
442 {
443 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
444 
445 	transport->inet->sk_write_pending--;
446 }
447 
448 /**
449  * xs_nospace - place task on wait queue if transmit was incomplete
450  * @task: task to put to sleep
451  *
452  */
453 static int xs_nospace(struct rpc_task *task)
454 {
455 	struct rpc_rqst *req = task->tk_rqstp;
456 	struct rpc_xprt *xprt = req->rq_xprt;
457 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
458 	struct sock *sk = transport->inet;
459 	int ret = -EAGAIN;
460 
461 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
462 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
463 			req->rq_slen);
464 
465 	/* Protect against races with write_space */
466 	spin_lock_bh(&xprt->transport_lock);
467 
468 	/* Don't race with disconnect */
469 	if (xprt_connected(xprt)) {
470 		/* wait for more buffer space */
471 		sk->sk_write_pending++;
472 		xprt_wait_for_buffer_space(task, xs_nospace_callback);
473 	} else
474 		ret = -ENOTCONN;
475 
476 	spin_unlock_bh(&xprt->transport_lock);
477 
478 	/* Race breaker in case memory is freed before above code is called */
479 	if (ret == -EAGAIN) {
480 		struct socket_wq *wq;
481 
482 		rcu_read_lock();
483 		wq = rcu_dereference(sk->sk_wq);
484 		set_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags);
485 		rcu_read_unlock();
486 
487 		sk->sk_write_space(sk);
488 	}
489 	return ret;
490 }
491 
492 /*
493  * Construct a stream transport record marker in @buf.
494  */
495 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
496 {
497 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
498 	rpc_fraghdr *base = buf->head[0].iov_base;
499 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
500 }
501 
502 /**
503  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
504  * @task: RPC task that manages the state of an RPC request
505  *
506  * Return values:
507  *        0:	The request has been sent
508  *   EAGAIN:	The socket was blocked, please call again later to
509  *		complete the request
510  * ENOTCONN:	Caller needs to invoke connect logic then call again
511  *    other:	Some other error occured, the request was not sent
512  */
513 static int xs_local_send_request(struct rpc_task *task)
514 {
515 	struct rpc_rqst *req = task->tk_rqstp;
516 	struct rpc_xprt *xprt = req->rq_xprt;
517 	struct sock_xprt *transport =
518 				container_of(xprt, struct sock_xprt, xprt);
519 	struct xdr_buf *xdr = &req->rq_snd_buf;
520 	int status;
521 	int sent = 0;
522 
523 	xs_encode_stream_record_marker(&req->rq_snd_buf);
524 
525 	xs_pktdump("packet data:",
526 			req->rq_svec->iov_base, req->rq_svec->iov_len);
527 
528 	status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
529 			      true, &sent);
530 	dprintk("RPC:       %s(%u) = %d\n",
531 			__func__, xdr->len - req->rq_bytes_sent, status);
532 
533 	if (status == -EAGAIN && sock_writeable(transport->inet))
534 		status = -ENOBUFS;
535 
536 	if (likely(sent > 0) || status == 0) {
537 		req->rq_bytes_sent += sent;
538 		req->rq_xmit_bytes_sent += sent;
539 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
540 			req->rq_bytes_sent = 0;
541 			return 0;
542 		}
543 		status = -EAGAIN;
544 	}
545 
546 	switch (status) {
547 	case -ENOBUFS:
548 		break;
549 	case -EAGAIN:
550 		status = xs_nospace(task);
551 		break;
552 	default:
553 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
554 			-status);
555 	case -EPIPE:
556 		xs_close(xprt);
557 		status = -ENOTCONN;
558 	}
559 
560 	return status;
561 }
562 
563 /**
564  * xs_udp_send_request - write an RPC request to a UDP socket
565  * @task: address of RPC task that manages the state of an RPC request
566  *
567  * Return values:
568  *        0:	The request has been sent
569  *   EAGAIN:	The socket was blocked, please call again later to
570  *		complete the request
571  * ENOTCONN:	Caller needs to invoke connect logic then call again
572  *    other:	Some other error occurred, the request was not sent
573  */
574 static int xs_udp_send_request(struct rpc_task *task)
575 {
576 	struct rpc_rqst *req = task->tk_rqstp;
577 	struct rpc_xprt *xprt = req->rq_xprt;
578 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
579 	struct xdr_buf *xdr = &req->rq_snd_buf;
580 	int sent = 0;
581 	int status;
582 
583 	xs_pktdump("packet data:",
584 				req->rq_svec->iov_base,
585 				req->rq_svec->iov_len);
586 
587 	if (!xprt_bound(xprt))
588 		return -ENOTCONN;
589 	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
590 			      xdr, req->rq_bytes_sent, true, &sent);
591 
592 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
593 			xdr->len - req->rq_bytes_sent, status);
594 
595 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
596 	if (status == -EPERM)
597 		goto process_status;
598 
599 	if (status == -EAGAIN && sock_writeable(transport->inet))
600 		status = -ENOBUFS;
601 
602 	if (sent > 0 || status == 0) {
603 		req->rq_xmit_bytes_sent += sent;
604 		if (sent >= req->rq_slen)
605 			return 0;
606 		/* Still some bytes left; set up for a retry later. */
607 		status = -EAGAIN;
608 	}
609 
610 process_status:
611 	switch (status) {
612 	case -ENOTSOCK:
613 		status = -ENOTCONN;
614 		/* Should we call xs_close() here? */
615 		break;
616 	case -EAGAIN:
617 		status = xs_nospace(task);
618 		break;
619 	case -ENETUNREACH:
620 	case -ENOBUFS:
621 	case -EPIPE:
622 	case -ECONNREFUSED:
623 	case -EPERM:
624 		/* When the server has died, an ICMP port unreachable message
625 		 * prompts ECONNREFUSED. */
626 		break;
627 	default:
628 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
629 			-status);
630 	}
631 
632 	return status;
633 }
634 
635 /**
636  * xs_tcp_send_request - write an RPC request to a TCP socket
637  * @task: address of RPC task that manages the state of an RPC request
638  *
639  * Return values:
640  *        0:	The request has been sent
641  *   EAGAIN:	The socket was blocked, please call again later to
642  *		complete the request
643  * ENOTCONN:	Caller needs to invoke connect logic then call again
644  *    other:	Some other error occurred, the request was not sent
645  *
646  * XXX: In the case of soft timeouts, should we eventually give up
647  *	if sendmsg is not able to make progress?
648  */
649 static int xs_tcp_send_request(struct rpc_task *task)
650 {
651 	struct rpc_rqst *req = task->tk_rqstp;
652 	struct rpc_xprt *xprt = req->rq_xprt;
653 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
654 	struct xdr_buf *xdr = &req->rq_snd_buf;
655 	bool zerocopy = true;
656 	bool vm_wait = false;
657 	int status;
658 	int sent;
659 
660 	xs_encode_stream_record_marker(&req->rq_snd_buf);
661 
662 	xs_pktdump("packet data:",
663 				req->rq_svec->iov_base,
664 				req->rq_svec->iov_len);
665 	/* Don't use zero copy if this is a resend. If the RPC call
666 	 * completes while the socket holds a reference to the pages,
667 	 * then we may end up resending corrupted data.
668 	 */
669 	if (task->tk_flags & RPC_TASK_SENT)
670 		zerocopy = false;
671 
672 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
673 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
674 
675 	/* Continue transmitting the packet/record. We must be careful
676 	 * to cope with writespace callbacks arriving _after_ we have
677 	 * called sendmsg(). */
678 	while (1) {
679 		sent = 0;
680 		status = xs_sendpages(transport->sock, NULL, 0, xdr,
681 				      req->rq_bytes_sent, zerocopy, &sent);
682 
683 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
684 				xdr->len - req->rq_bytes_sent, status);
685 
686 		/* If we've sent the entire packet, immediately
687 		 * reset the count of bytes sent. */
688 		req->rq_bytes_sent += sent;
689 		req->rq_xmit_bytes_sent += sent;
690 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
691 			req->rq_bytes_sent = 0;
692 			return 0;
693 		}
694 
695 		WARN_ON_ONCE(sent == 0 && status == 0);
696 
697 		if (status == -EAGAIN ) {
698 			/*
699 			 * Return EAGAIN if we're sure we're hitting the
700 			 * socket send buffer limits.
701 			 */
702 			if (test_bit(SOCK_NOSPACE, &transport->sock->flags))
703 				break;
704 			/*
705 			 * Did we hit a memory allocation failure?
706 			 */
707 			if (sent == 0) {
708 				status = -ENOBUFS;
709 				if (vm_wait)
710 					break;
711 				/* Retry, knowing now that we're below the
712 				 * socket send buffer limit
713 				 */
714 				vm_wait = true;
715 			}
716 			continue;
717 		}
718 		if (status < 0)
719 			break;
720 		vm_wait = false;
721 	}
722 
723 	switch (status) {
724 	case -ENOTSOCK:
725 		status = -ENOTCONN;
726 		/* Should we call xs_close() here? */
727 		break;
728 	case -EAGAIN:
729 		status = xs_nospace(task);
730 		break;
731 	case -ECONNRESET:
732 	case -ECONNREFUSED:
733 	case -ENOTCONN:
734 	case -EADDRINUSE:
735 	case -ENOBUFS:
736 	case -EPIPE:
737 		break;
738 	default:
739 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
740 			-status);
741 	}
742 
743 	return status;
744 }
745 
746 /**
747  * xs_tcp_release_xprt - clean up after a tcp transmission
748  * @xprt: transport
749  * @task: rpc task
750  *
751  * This cleans up if an error causes us to abort the transmission of a request.
752  * In this case, the socket may need to be reset in order to avoid confusing
753  * the server.
754  */
755 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
756 {
757 	struct rpc_rqst *req;
758 
759 	if (task != xprt->snd_task)
760 		return;
761 	if (task == NULL)
762 		goto out_release;
763 	req = task->tk_rqstp;
764 	if (req == NULL)
765 		goto out_release;
766 	if (req->rq_bytes_sent == 0)
767 		goto out_release;
768 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
769 		goto out_release;
770 	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
771 out_release:
772 	xprt_release_xprt(xprt, task);
773 }
774 
775 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
776 {
777 	transport->old_data_ready = sk->sk_data_ready;
778 	transport->old_state_change = sk->sk_state_change;
779 	transport->old_write_space = sk->sk_write_space;
780 	transport->old_error_report = sk->sk_error_report;
781 }
782 
783 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
784 {
785 	sk->sk_data_ready = transport->old_data_ready;
786 	sk->sk_state_change = transport->old_state_change;
787 	sk->sk_write_space = transport->old_write_space;
788 	sk->sk_error_report = transport->old_error_report;
789 }
790 
791 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
792 {
793 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
794 
795 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
796 }
797 
798 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
799 {
800 	smp_mb__before_atomic();
801 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
802 	clear_bit(XPRT_CLOSING, &xprt->state);
803 	xs_sock_reset_state_flags(xprt);
804 	smp_mb__after_atomic();
805 }
806 
807 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
808 {
809 	xs_sock_reset_connection_flags(xprt);
810 	/* Mark transport as closed and wake up all pending tasks */
811 	xprt_disconnect_done(xprt);
812 }
813 
814 /**
815  * xs_error_report - callback to handle TCP socket state errors
816  * @sk: socket
817  *
818  * Note: we don't call sock_error() since there may be a rpc_task
819  * using the socket, and so we don't want to clear sk->sk_err.
820  */
821 static void xs_error_report(struct sock *sk)
822 {
823 	struct rpc_xprt *xprt;
824 	int err;
825 
826 	read_lock_bh(&sk->sk_callback_lock);
827 	if (!(xprt = xprt_from_sock(sk)))
828 		goto out;
829 
830 	err = -sk->sk_err;
831 	if (err == 0)
832 		goto out;
833 	/* Is this a reset event? */
834 	if (sk->sk_state == TCP_CLOSE)
835 		xs_sock_mark_closed(xprt);
836 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
837 			xprt, -err);
838 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
839 	xprt_wake_pending_tasks(xprt, err);
840  out:
841 	read_unlock_bh(&sk->sk_callback_lock);
842 }
843 
844 static void xs_reset_transport(struct sock_xprt *transport)
845 {
846 	struct socket *sock = transport->sock;
847 	struct sock *sk = transport->inet;
848 	struct rpc_xprt *xprt = &transport->xprt;
849 
850 	if (sk == NULL)
851 		return;
852 
853 	if (atomic_read(&transport->xprt.swapper))
854 		sk_clear_memalloc(sk);
855 
856 	kernel_sock_shutdown(sock, SHUT_RDWR);
857 
858 	mutex_lock(&transport->recv_mutex);
859 	write_lock_bh(&sk->sk_callback_lock);
860 	transport->inet = NULL;
861 	transport->sock = NULL;
862 
863 	sk->sk_user_data = NULL;
864 
865 	xs_restore_old_callbacks(transport, sk);
866 	xprt_clear_connected(xprt);
867 	write_unlock_bh(&sk->sk_callback_lock);
868 	xs_sock_reset_connection_flags(xprt);
869 	mutex_unlock(&transport->recv_mutex);
870 
871 	trace_rpc_socket_close(xprt, sock);
872 	sock_release(sock);
873 }
874 
875 /**
876  * xs_close - close a socket
877  * @xprt: transport
878  *
879  * This is used when all requests are complete; ie, no DRC state remains
880  * on the server we want to save.
881  *
882  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
883  * xs_reset_transport() zeroing the socket from underneath a writer.
884  */
885 static void xs_close(struct rpc_xprt *xprt)
886 {
887 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
888 
889 	dprintk("RPC:       xs_close xprt %p\n", xprt);
890 
891 	xs_reset_transport(transport);
892 	xprt->reestablish_timeout = 0;
893 
894 	xprt_disconnect_done(xprt);
895 }
896 
897 static void xs_inject_disconnect(struct rpc_xprt *xprt)
898 {
899 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
900 		xprt);
901 	xprt_disconnect_done(xprt);
902 }
903 
904 static void xs_xprt_free(struct rpc_xprt *xprt)
905 {
906 	xs_free_peer_addresses(xprt);
907 	xprt_free(xprt);
908 }
909 
910 /**
911  * xs_destroy - prepare to shutdown a transport
912  * @xprt: doomed transport
913  *
914  */
915 static void xs_destroy(struct rpc_xprt *xprt)
916 {
917 	struct sock_xprt *transport = container_of(xprt,
918 			struct sock_xprt, xprt);
919 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
920 
921 	cancel_delayed_work_sync(&transport->connect_worker);
922 	xs_close(xprt);
923 	cancel_work_sync(&transport->recv_worker);
924 	xs_xprt_free(xprt);
925 	module_put(THIS_MODULE);
926 }
927 
928 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
929 {
930 	struct xdr_skb_reader desc = {
931 		.skb		= skb,
932 		.offset		= sizeof(rpc_fraghdr),
933 		.count		= skb->len - sizeof(rpc_fraghdr),
934 	};
935 
936 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
937 		return -1;
938 	if (desc.count)
939 		return -1;
940 	return 0;
941 }
942 
943 /**
944  * xs_local_data_read_skb
945  * @xprt: transport
946  * @sk: socket
947  * @skb: skbuff
948  *
949  * Currently this assumes we can read the whole reply in a single gulp.
950  */
951 static void xs_local_data_read_skb(struct rpc_xprt *xprt,
952 		struct sock *sk,
953 		struct sk_buff *skb)
954 {
955 	struct rpc_task *task;
956 	struct rpc_rqst *rovr;
957 	int repsize, copied;
958 	u32 _xid;
959 	__be32 *xp;
960 
961 	repsize = skb->len - sizeof(rpc_fraghdr);
962 	if (repsize < 4) {
963 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
964 		return;
965 	}
966 
967 	/* Copy the XID from the skb... */
968 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
969 	if (xp == NULL)
970 		return;
971 
972 	/* Look up and lock the request corresponding to the given XID */
973 	spin_lock(&xprt->recv_lock);
974 	rovr = xprt_lookup_rqst(xprt, *xp);
975 	if (!rovr)
976 		goto out_unlock;
977 	xprt_pin_rqst(rovr);
978 	spin_unlock(&xprt->recv_lock);
979 	task = rovr->rq_task;
980 
981 	copied = rovr->rq_private_buf.buflen;
982 	if (copied > repsize)
983 		copied = repsize;
984 
985 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
986 		dprintk("RPC:       sk_buff copy failed\n");
987 		spin_lock(&xprt->recv_lock);
988 		goto out_unpin;
989 	}
990 
991 	spin_lock(&xprt->recv_lock);
992 	xprt_complete_rqst(task, copied);
993 out_unpin:
994 	xprt_unpin_rqst(rovr);
995  out_unlock:
996 	spin_unlock(&xprt->recv_lock);
997 }
998 
999 static void xs_local_data_receive(struct sock_xprt *transport)
1000 {
1001 	struct sk_buff *skb;
1002 	struct sock *sk;
1003 	int err;
1004 
1005 	mutex_lock(&transport->recv_mutex);
1006 	sk = transport->inet;
1007 	if (sk == NULL)
1008 		goto out;
1009 	for (;;) {
1010 		skb = skb_recv_datagram(sk, 0, 1, &err);
1011 		if (skb != NULL) {
1012 			xs_local_data_read_skb(&transport->xprt, sk, skb);
1013 			skb_free_datagram(sk, skb);
1014 			continue;
1015 		}
1016 		if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1017 			break;
1018 	}
1019 out:
1020 	mutex_unlock(&transport->recv_mutex);
1021 }
1022 
1023 static void xs_local_data_receive_workfn(struct work_struct *work)
1024 {
1025 	struct sock_xprt *transport =
1026 		container_of(work, struct sock_xprt, recv_worker);
1027 	xs_local_data_receive(transport);
1028 }
1029 
1030 /**
1031  * xs_udp_data_read_skb - receive callback for UDP sockets
1032  * @xprt: transport
1033  * @sk: socket
1034  * @skb: skbuff
1035  *
1036  */
1037 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1038 		struct sock *sk,
1039 		struct sk_buff *skb)
1040 {
1041 	struct rpc_task *task;
1042 	struct rpc_rqst *rovr;
1043 	int repsize, copied;
1044 	u32 _xid;
1045 	__be32 *xp;
1046 
1047 	repsize = skb->len;
1048 	if (repsize < 4) {
1049 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1050 		return;
1051 	}
1052 
1053 	/* Copy the XID from the skb... */
1054 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1055 	if (xp == NULL)
1056 		return;
1057 
1058 	/* Look up and lock the request corresponding to the given XID */
1059 	spin_lock(&xprt->recv_lock);
1060 	rovr = xprt_lookup_rqst(xprt, *xp);
1061 	if (!rovr)
1062 		goto out_unlock;
1063 	xprt_pin_rqst(rovr);
1064 	spin_unlock(&xprt->recv_lock);
1065 	task = rovr->rq_task;
1066 
1067 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1068 		copied = repsize;
1069 
1070 	/* Suck it into the iovec, verify checksum if not done by hw. */
1071 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1072 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1073 		spin_lock(&xprt->recv_lock);
1074 		goto out_unpin;
1075 	}
1076 
1077 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1078 
1079 	spin_lock_bh(&xprt->transport_lock);
1080 	xprt_adjust_cwnd(xprt, task, copied);
1081 	spin_unlock_bh(&xprt->transport_lock);
1082 	spin_lock(&xprt->recv_lock);
1083 	xprt_complete_rqst(task, copied);
1084 out_unpin:
1085 	xprt_unpin_rqst(rovr);
1086  out_unlock:
1087 	spin_unlock(&xprt->recv_lock);
1088 }
1089 
1090 static void xs_udp_data_receive(struct sock_xprt *transport)
1091 {
1092 	struct sk_buff *skb;
1093 	struct sock *sk;
1094 	int err;
1095 
1096 	mutex_lock(&transport->recv_mutex);
1097 	sk = transport->inet;
1098 	if (sk == NULL)
1099 		goto out;
1100 	for (;;) {
1101 		skb = skb_recv_udp(sk, 0, 1, &err);
1102 		if (skb != NULL) {
1103 			xs_udp_data_read_skb(&transport->xprt, sk, skb);
1104 			consume_skb(skb);
1105 			continue;
1106 		}
1107 		if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1108 			break;
1109 	}
1110 out:
1111 	mutex_unlock(&transport->recv_mutex);
1112 }
1113 
1114 static void xs_udp_data_receive_workfn(struct work_struct *work)
1115 {
1116 	struct sock_xprt *transport =
1117 		container_of(work, struct sock_xprt, recv_worker);
1118 	xs_udp_data_receive(transport);
1119 }
1120 
1121 /**
1122  * xs_data_ready - "data ready" callback for UDP sockets
1123  * @sk: socket with data to read
1124  *
1125  */
1126 static void xs_data_ready(struct sock *sk)
1127 {
1128 	struct rpc_xprt *xprt;
1129 
1130 	read_lock_bh(&sk->sk_callback_lock);
1131 	dprintk("RPC:       xs_data_ready...\n");
1132 	xprt = xprt_from_sock(sk);
1133 	if (xprt != NULL) {
1134 		struct sock_xprt *transport = container_of(xprt,
1135 				struct sock_xprt, xprt);
1136 		transport->old_data_ready(sk);
1137 		/* Any data means we had a useful conversation, so
1138 		 * then we don't need to delay the next reconnect
1139 		 */
1140 		if (xprt->reestablish_timeout)
1141 			xprt->reestablish_timeout = 0;
1142 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1143 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1144 	}
1145 	read_unlock_bh(&sk->sk_callback_lock);
1146 }
1147 
1148 /*
1149  * Helper function to force a TCP close if the server is sending
1150  * junk and/or it has put us in CLOSE_WAIT
1151  */
1152 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1153 {
1154 	xprt_force_disconnect(xprt);
1155 }
1156 
1157 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1158 {
1159 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1160 	size_t len, used;
1161 	char *p;
1162 
1163 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1164 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1165 	used = xdr_skb_read_bits(desc, p, len);
1166 	transport->tcp_offset += used;
1167 	if (used != len)
1168 		return;
1169 
1170 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1171 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1172 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1173 	else
1174 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1175 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1176 
1177 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1178 	transport->tcp_offset = 0;
1179 
1180 	/* Sanity check of the record length */
1181 	if (unlikely(transport->tcp_reclen < 8)) {
1182 		dprintk("RPC:       invalid TCP record fragment length\n");
1183 		xs_tcp_force_close(xprt);
1184 		return;
1185 	}
1186 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1187 			transport->tcp_reclen);
1188 }
1189 
1190 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1191 {
1192 	if (transport->tcp_offset == transport->tcp_reclen) {
1193 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1194 		transport->tcp_offset = 0;
1195 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1196 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1197 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1198 			transport->tcp_copied = 0;
1199 		}
1200 	}
1201 }
1202 
1203 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1204 {
1205 	size_t len, used;
1206 	char *p;
1207 
1208 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1209 	dprintk("RPC:       reading XID (%zu bytes)\n", len);
1210 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1211 	used = xdr_skb_read_bits(desc, p, len);
1212 	transport->tcp_offset += used;
1213 	if (used != len)
1214 		return;
1215 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1216 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1217 	transport->tcp_copied = 4;
1218 	dprintk("RPC:       reading %s XID %08x\n",
1219 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1220 							      : "request with",
1221 			ntohl(transport->tcp_xid));
1222 	xs_tcp_check_fraghdr(transport);
1223 }
1224 
1225 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1226 				       struct xdr_skb_reader *desc)
1227 {
1228 	size_t len, used;
1229 	u32 offset;
1230 	char *p;
1231 
1232 	/*
1233 	 * We want transport->tcp_offset to be 8 at the end of this routine
1234 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1235 	 * When this function is called for the first time,
1236 	 * transport->tcp_offset is 4 (after having already read the xid).
1237 	 */
1238 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1239 	len = sizeof(transport->tcp_calldir) - offset;
1240 	dprintk("RPC:       reading CALL/REPLY flag (%zu bytes)\n", len);
1241 	p = ((char *) &transport->tcp_calldir) + offset;
1242 	used = xdr_skb_read_bits(desc, p, len);
1243 	transport->tcp_offset += used;
1244 	if (used != len)
1245 		return;
1246 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1247 	/*
1248 	 * We don't yet have the XDR buffer, so we will write the calldir
1249 	 * out after we get the buffer from the 'struct rpc_rqst'
1250 	 */
1251 	switch (ntohl(transport->tcp_calldir)) {
1252 	case RPC_REPLY:
1253 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1254 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1255 		transport->tcp_flags |= TCP_RPC_REPLY;
1256 		break;
1257 	case RPC_CALL:
1258 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1259 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1260 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1261 		break;
1262 	default:
1263 		dprintk("RPC:       invalid request message type\n");
1264 		xs_tcp_force_close(&transport->xprt);
1265 	}
1266 	xs_tcp_check_fraghdr(transport);
1267 }
1268 
1269 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1270 				     struct xdr_skb_reader *desc,
1271 				     struct rpc_rqst *req)
1272 {
1273 	struct sock_xprt *transport =
1274 				container_of(xprt, struct sock_xprt, xprt);
1275 	struct xdr_buf *rcvbuf;
1276 	size_t len;
1277 	ssize_t r;
1278 
1279 	rcvbuf = &req->rq_private_buf;
1280 
1281 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1282 		/*
1283 		 * Save the RPC direction in the XDR buffer
1284 		 */
1285 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1286 			&transport->tcp_calldir,
1287 			sizeof(transport->tcp_calldir));
1288 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1289 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1290 	}
1291 
1292 	len = desc->count;
1293 	if (len > transport->tcp_reclen - transport->tcp_offset)
1294 		desc->count = transport->tcp_reclen - transport->tcp_offset;
1295 	r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1296 					  desc, xdr_skb_read_bits);
1297 
1298 	if (desc->count) {
1299 		/* Error when copying to the receive buffer,
1300 		 * usually because we weren't able to allocate
1301 		 * additional buffer pages. All we can do now
1302 		 * is turn off TCP_RCV_COPY_DATA, so the request
1303 		 * will not receive any additional updates,
1304 		 * and time out.
1305 		 * Any remaining data from this record will
1306 		 * be discarded.
1307 		 */
1308 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1309 		dprintk("RPC:       XID %08x truncated request\n",
1310 				ntohl(transport->tcp_xid));
1311 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1312 				"tcp_offset = %u, tcp_reclen = %u\n",
1313 				xprt, transport->tcp_copied,
1314 				transport->tcp_offset, transport->tcp_reclen);
1315 		return;
1316 	}
1317 
1318 	transport->tcp_copied += r;
1319 	transport->tcp_offset += r;
1320 	desc->count = len - r;
1321 
1322 	dprintk("RPC:       XID %08x read %zd bytes\n",
1323 			ntohl(transport->tcp_xid), r);
1324 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1325 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1326 			transport->tcp_offset, transport->tcp_reclen);
1327 
1328 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1329 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1330 	else if (transport->tcp_offset == transport->tcp_reclen) {
1331 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1332 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1333 	}
1334 }
1335 
1336 /*
1337  * Finds the request corresponding to the RPC xid and invokes the common
1338  * tcp read code to read the data.
1339  */
1340 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1341 				    struct xdr_skb_reader *desc)
1342 {
1343 	struct sock_xprt *transport =
1344 				container_of(xprt, struct sock_xprt, xprt);
1345 	struct rpc_rqst *req;
1346 
1347 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1348 
1349 	/* Find and lock the request corresponding to this xid */
1350 	spin_lock(&xprt->recv_lock);
1351 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1352 	if (!req) {
1353 		dprintk("RPC:       XID %08x request not found!\n",
1354 				ntohl(transport->tcp_xid));
1355 		spin_unlock(&xprt->recv_lock);
1356 		return -1;
1357 	}
1358 	xprt_pin_rqst(req);
1359 	spin_unlock(&xprt->recv_lock);
1360 
1361 	xs_tcp_read_common(xprt, desc, req);
1362 
1363 	spin_lock(&xprt->recv_lock);
1364 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1365 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1366 	xprt_unpin_rqst(req);
1367 	spin_unlock(&xprt->recv_lock);
1368 	return 0;
1369 }
1370 
1371 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1372 /*
1373  * Obtains an rpc_rqst previously allocated and invokes the common
1374  * tcp read code to read the data.  The result is placed in the callback
1375  * queue.
1376  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1377  * connection and return -1.
1378  */
1379 static int xs_tcp_read_callback(struct rpc_xprt *xprt,
1380 				       struct xdr_skb_reader *desc)
1381 {
1382 	struct sock_xprt *transport =
1383 				container_of(xprt, struct sock_xprt, xprt);
1384 	struct rpc_rqst *req;
1385 
1386 	/* Look up the request corresponding to the given XID */
1387 	req = xprt_lookup_bc_request(xprt, transport->tcp_xid);
1388 	if (req == NULL) {
1389 		printk(KERN_WARNING "Callback slot table overflowed\n");
1390 		xprt_force_disconnect(xprt);
1391 		return -1;
1392 	}
1393 
1394 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1395 	xs_tcp_read_common(xprt, desc, req);
1396 
1397 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1398 		xprt_complete_bc_request(req, transport->tcp_copied);
1399 
1400 	return 0;
1401 }
1402 
1403 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1404 					struct xdr_skb_reader *desc)
1405 {
1406 	struct sock_xprt *transport =
1407 				container_of(xprt, struct sock_xprt, xprt);
1408 
1409 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1410 		xs_tcp_read_reply(xprt, desc) :
1411 		xs_tcp_read_callback(xprt, desc);
1412 }
1413 
1414 static int xs_tcp_bc_up(struct svc_serv *serv, struct net *net)
1415 {
1416 	int ret;
1417 
1418 	ret = svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
1419 			      SVC_SOCK_ANONYMOUS);
1420 	if (ret < 0)
1421 		return ret;
1422 	return 0;
1423 }
1424 
1425 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1426 {
1427 	return PAGE_SIZE;
1428 }
1429 #else
1430 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1431 					struct xdr_skb_reader *desc)
1432 {
1433 	return xs_tcp_read_reply(xprt, desc);
1434 }
1435 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1436 
1437 /*
1438  * Read data off the transport.  This can be either an RPC_CALL or an
1439  * RPC_REPLY.  Relay the processing to helper functions.
1440  */
1441 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1442 				    struct xdr_skb_reader *desc)
1443 {
1444 	struct sock_xprt *transport =
1445 				container_of(xprt, struct sock_xprt, xprt);
1446 
1447 	if (_xs_tcp_read_data(xprt, desc) == 0)
1448 		xs_tcp_check_fraghdr(transport);
1449 	else {
1450 		/*
1451 		 * The transport_lock protects the request handling.
1452 		 * There's no need to hold it to update the tcp_flags.
1453 		 */
1454 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1455 	}
1456 }
1457 
1458 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1459 {
1460 	size_t len;
1461 
1462 	len = transport->tcp_reclen - transport->tcp_offset;
1463 	if (len > desc->count)
1464 		len = desc->count;
1465 	desc->count -= len;
1466 	desc->offset += len;
1467 	transport->tcp_offset += len;
1468 	dprintk("RPC:       discarded %zu bytes\n", len);
1469 	xs_tcp_check_fraghdr(transport);
1470 }
1471 
1472 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1473 {
1474 	struct rpc_xprt *xprt = rd_desc->arg.data;
1475 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1476 	struct xdr_skb_reader desc = {
1477 		.skb	= skb,
1478 		.offset	= offset,
1479 		.count	= len,
1480 	};
1481 
1482 	dprintk("RPC:       xs_tcp_data_recv started\n");
1483 	do {
1484 		trace_xs_tcp_data_recv(transport);
1485 		/* Read in a new fragment marker if necessary */
1486 		/* Can we ever really expect to get completely empty fragments? */
1487 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1488 			xs_tcp_read_fraghdr(xprt, &desc);
1489 			continue;
1490 		}
1491 		/* Read in the xid if necessary */
1492 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1493 			xs_tcp_read_xid(transport, &desc);
1494 			continue;
1495 		}
1496 		/* Read in the call/reply flag */
1497 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1498 			xs_tcp_read_calldir(transport, &desc);
1499 			continue;
1500 		}
1501 		/* Read in the request data */
1502 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1503 			xs_tcp_read_data(xprt, &desc);
1504 			continue;
1505 		}
1506 		/* Skip over any trailing bytes on short reads */
1507 		xs_tcp_read_discard(transport, &desc);
1508 	} while (desc.count);
1509 	trace_xs_tcp_data_recv(transport);
1510 	dprintk("RPC:       xs_tcp_data_recv done\n");
1511 	return len - desc.count;
1512 }
1513 
1514 static void xs_tcp_data_receive(struct sock_xprt *transport)
1515 {
1516 	struct rpc_xprt *xprt = &transport->xprt;
1517 	struct sock *sk;
1518 	read_descriptor_t rd_desc = {
1519 		.count = 2*1024*1024,
1520 		.arg.data = xprt,
1521 	};
1522 	unsigned long total = 0;
1523 	int loop;
1524 	int read = 0;
1525 
1526 	mutex_lock(&transport->recv_mutex);
1527 	sk = transport->inet;
1528 	if (sk == NULL)
1529 		goto out;
1530 
1531 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1532 	for (loop = 0; loop < 64; loop++) {
1533 		lock_sock(sk);
1534 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1535 		if (read <= 0) {
1536 			clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1537 			release_sock(sk);
1538 			break;
1539 		}
1540 		release_sock(sk);
1541 		total += read;
1542 		rd_desc.count = 65536;
1543 	}
1544 	if (test_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1545 		queue_work(xprtiod_workqueue, &transport->recv_worker);
1546 out:
1547 	mutex_unlock(&transport->recv_mutex);
1548 	trace_xs_tcp_data_ready(xprt, read, total);
1549 }
1550 
1551 static void xs_tcp_data_receive_workfn(struct work_struct *work)
1552 {
1553 	struct sock_xprt *transport =
1554 		container_of(work, struct sock_xprt, recv_worker);
1555 	xs_tcp_data_receive(transport);
1556 }
1557 
1558 /**
1559  * xs_tcp_state_change - callback to handle TCP socket state changes
1560  * @sk: socket whose state has changed
1561  *
1562  */
1563 static void xs_tcp_state_change(struct sock *sk)
1564 {
1565 	struct rpc_xprt *xprt;
1566 	struct sock_xprt *transport;
1567 
1568 	read_lock_bh(&sk->sk_callback_lock);
1569 	if (!(xprt = xprt_from_sock(sk)))
1570 		goto out;
1571 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1572 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1573 			sk->sk_state, xprt_connected(xprt),
1574 			sock_flag(sk, SOCK_DEAD),
1575 			sock_flag(sk, SOCK_ZAPPED),
1576 			sk->sk_shutdown);
1577 
1578 	transport = container_of(xprt, struct sock_xprt, xprt);
1579 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1580 	switch (sk->sk_state) {
1581 	case TCP_ESTABLISHED:
1582 		spin_lock(&xprt->transport_lock);
1583 		if (!xprt_test_and_set_connected(xprt)) {
1584 
1585 			/* Reset TCP record info */
1586 			transport->tcp_offset = 0;
1587 			transport->tcp_reclen = 0;
1588 			transport->tcp_copied = 0;
1589 			transport->tcp_flags =
1590 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1591 			xprt->connect_cookie++;
1592 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1593 			xprt_clear_connecting(xprt);
1594 
1595 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1596 		}
1597 		spin_unlock(&xprt->transport_lock);
1598 		break;
1599 	case TCP_FIN_WAIT1:
1600 		/* The client initiated a shutdown of the socket */
1601 		xprt->connect_cookie++;
1602 		xprt->reestablish_timeout = 0;
1603 		set_bit(XPRT_CLOSING, &xprt->state);
1604 		smp_mb__before_atomic();
1605 		clear_bit(XPRT_CONNECTED, &xprt->state);
1606 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1607 		smp_mb__after_atomic();
1608 		break;
1609 	case TCP_CLOSE_WAIT:
1610 		/* The server initiated a shutdown of the socket */
1611 		xprt->connect_cookie++;
1612 		clear_bit(XPRT_CONNECTED, &xprt->state);
1613 		xs_tcp_force_close(xprt);
1614 	case TCP_CLOSING:
1615 		/*
1616 		 * If the server closed down the connection, make sure that
1617 		 * we back off before reconnecting
1618 		 */
1619 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1620 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1621 		break;
1622 	case TCP_LAST_ACK:
1623 		set_bit(XPRT_CLOSING, &xprt->state);
1624 		smp_mb__before_atomic();
1625 		clear_bit(XPRT_CONNECTED, &xprt->state);
1626 		smp_mb__after_atomic();
1627 		break;
1628 	case TCP_CLOSE:
1629 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1630 					&transport->sock_state))
1631 			xprt_clear_connecting(xprt);
1632 		if (sk->sk_err)
1633 			xprt_wake_pending_tasks(xprt, -sk->sk_err);
1634 		xs_sock_mark_closed(xprt);
1635 	}
1636  out:
1637 	read_unlock_bh(&sk->sk_callback_lock);
1638 }
1639 
1640 static void xs_write_space(struct sock *sk)
1641 {
1642 	struct socket_wq *wq;
1643 	struct rpc_xprt *xprt;
1644 
1645 	if (!sk->sk_socket)
1646 		return;
1647 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1648 
1649 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1650 		return;
1651 	rcu_read_lock();
1652 	wq = rcu_dereference(sk->sk_wq);
1653 	if (!wq || test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags) == 0)
1654 		goto out;
1655 
1656 	xprt_write_space(xprt);
1657 out:
1658 	rcu_read_unlock();
1659 }
1660 
1661 /**
1662  * xs_udp_write_space - callback invoked when socket buffer space
1663  *                             becomes available
1664  * @sk: socket whose state has changed
1665  *
1666  * Called when more output buffer space is available for this socket.
1667  * We try not to wake our writers until they can make "significant"
1668  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1669  * with a bunch of small requests.
1670  */
1671 static void xs_udp_write_space(struct sock *sk)
1672 {
1673 	read_lock_bh(&sk->sk_callback_lock);
1674 
1675 	/* from net/core/sock.c:sock_def_write_space */
1676 	if (sock_writeable(sk))
1677 		xs_write_space(sk);
1678 
1679 	read_unlock_bh(&sk->sk_callback_lock);
1680 }
1681 
1682 /**
1683  * xs_tcp_write_space - callback invoked when socket buffer space
1684  *                             becomes available
1685  * @sk: socket whose state has changed
1686  *
1687  * Called when more output buffer space is available for this socket.
1688  * We try not to wake our writers until they can make "significant"
1689  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1690  * with a bunch of small requests.
1691  */
1692 static void xs_tcp_write_space(struct sock *sk)
1693 {
1694 	read_lock_bh(&sk->sk_callback_lock);
1695 
1696 	/* from net/core/stream.c:sk_stream_write_space */
1697 	if (sk_stream_is_writeable(sk))
1698 		xs_write_space(sk);
1699 
1700 	read_unlock_bh(&sk->sk_callback_lock);
1701 }
1702 
1703 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1704 {
1705 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1706 	struct sock *sk = transport->inet;
1707 
1708 	if (transport->rcvsize) {
1709 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1710 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1711 	}
1712 	if (transport->sndsize) {
1713 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1714 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1715 		sk->sk_write_space(sk);
1716 	}
1717 }
1718 
1719 /**
1720  * xs_udp_set_buffer_size - set send and receive limits
1721  * @xprt: generic transport
1722  * @sndsize: requested size of send buffer, in bytes
1723  * @rcvsize: requested size of receive buffer, in bytes
1724  *
1725  * Set socket send and receive buffer size limits.
1726  */
1727 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1728 {
1729 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1730 
1731 	transport->sndsize = 0;
1732 	if (sndsize)
1733 		transport->sndsize = sndsize + 1024;
1734 	transport->rcvsize = 0;
1735 	if (rcvsize)
1736 		transport->rcvsize = rcvsize + 1024;
1737 
1738 	xs_udp_do_set_buffer_size(xprt);
1739 }
1740 
1741 /**
1742  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1743  * @task: task that timed out
1744  *
1745  * Adjust the congestion window after a retransmit timeout has occurred.
1746  */
1747 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1748 {
1749 	spin_lock_bh(&xprt->transport_lock);
1750 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1751 	spin_unlock_bh(&xprt->transport_lock);
1752 }
1753 
1754 static unsigned short xs_get_random_port(void)
1755 {
1756 	unsigned short range = xprt_max_resvport - xprt_min_resvport + 1;
1757 	unsigned short rand = (unsigned short) prandom_u32() % range;
1758 	return rand + xprt_min_resvport;
1759 }
1760 
1761 /**
1762  * xs_set_reuseaddr_port - set the socket's port and address reuse options
1763  * @sock: socket
1764  *
1765  * Note that this function has to be called on all sockets that share the
1766  * same port, and it must be called before binding.
1767  */
1768 static void xs_sock_set_reuseport(struct socket *sock)
1769 {
1770 	int opt = 1;
1771 
1772 	kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
1773 			(char *)&opt, sizeof(opt));
1774 }
1775 
1776 static unsigned short xs_sock_getport(struct socket *sock)
1777 {
1778 	struct sockaddr_storage buf;
1779 	int buflen;
1780 	unsigned short port = 0;
1781 
1782 	if (kernel_getsockname(sock, (struct sockaddr *)&buf, &buflen) < 0)
1783 		goto out;
1784 	switch (buf.ss_family) {
1785 	case AF_INET6:
1786 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1787 		break;
1788 	case AF_INET:
1789 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1790 	}
1791 out:
1792 	return port;
1793 }
1794 
1795 /**
1796  * xs_set_port - reset the port number in the remote endpoint address
1797  * @xprt: generic transport
1798  * @port: new port number
1799  *
1800  */
1801 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1802 {
1803 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1804 
1805 	rpc_set_port(xs_addr(xprt), port);
1806 	xs_update_peer_port(xprt);
1807 }
1808 
1809 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1810 {
1811 	if (transport->srcport == 0)
1812 		transport->srcport = xs_sock_getport(sock);
1813 }
1814 
1815 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1816 {
1817 	unsigned short port = transport->srcport;
1818 
1819 	if (port == 0 && transport->xprt.resvport)
1820 		port = xs_get_random_port();
1821 	return port;
1822 }
1823 
1824 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1825 {
1826 	if (transport->srcport != 0)
1827 		transport->srcport = 0;
1828 	if (!transport->xprt.resvport)
1829 		return 0;
1830 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1831 		return xprt_max_resvport;
1832 	return --port;
1833 }
1834 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1835 {
1836 	struct sockaddr_storage myaddr;
1837 	int err, nloop = 0;
1838 	unsigned short port = xs_get_srcport(transport);
1839 	unsigned short last;
1840 
1841 	/*
1842 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1843 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1844 	 * port selection happen implicitly when the socket is used
1845 	 * (for example at connect time).
1846 	 *
1847 	 * This ensures that we can continue to establish TCP
1848 	 * connections even when all local ephemeral ports are already
1849 	 * a part of some TCP connection.  This makes no difference
1850 	 * for UDP sockets, but also doens't harm them.
1851 	 *
1852 	 * If we're asking for any reserved port (i.e. port == 0 &&
1853 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1854 	 * ensure that port is non-zero and we will bind as needed.
1855 	 */
1856 	if (port == 0)
1857 		return 0;
1858 
1859 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1860 	do {
1861 		rpc_set_port((struct sockaddr *)&myaddr, port);
1862 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1863 				transport->xprt.addrlen);
1864 		if (err == 0) {
1865 			transport->srcport = port;
1866 			break;
1867 		}
1868 		last = port;
1869 		port = xs_next_srcport(transport, port);
1870 		if (port > last)
1871 			nloop++;
1872 	} while (err == -EADDRINUSE && nloop != 2);
1873 
1874 	if (myaddr.ss_family == AF_INET)
1875 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1876 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1877 				port, err ? "failed" : "ok", err);
1878 	else
1879 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1880 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1881 				port, err ? "failed" : "ok", err);
1882 	return err;
1883 }
1884 
1885 /*
1886  * We don't support autobind on AF_LOCAL sockets
1887  */
1888 static void xs_local_rpcbind(struct rpc_task *task)
1889 {
1890 	xprt_set_bound(task->tk_xprt);
1891 }
1892 
1893 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1894 {
1895 }
1896 
1897 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1898 static struct lock_class_key xs_key[2];
1899 static struct lock_class_key xs_slock_key[2];
1900 
1901 static inline void xs_reclassify_socketu(struct socket *sock)
1902 {
1903 	struct sock *sk = sock->sk;
1904 
1905 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1906 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1907 }
1908 
1909 static inline void xs_reclassify_socket4(struct socket *sock)
1910 {
1911 	struct sock *sk = sock->sk;
1912 
1913 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1914 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1915 }
1916 
1917 static inline void xs_reclassify_socket6(struct socket *sock)
1918 {
1919 	struct sock *sk = sock->sk;
1920 
1921 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1922 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1923 }
1924 
1925 static inline void xs_reclassify_socket(int family, struct socket *sock)
1926 {
1927 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1928 		return;
1929 
1930 	switch (family) {
1931 	case AF_LOCAL:
1932 		xs_reclassify_socketu(sock);
1933 		break;
1934 	case AF_INET:
1935 		xs_reclassify_socket4(sock);
1936 		break;
1937 	case AF_INET6:
1938 		xs_reclassify_socket6(sock);
1939 		break;
1940 	}
1941 }
1942 #else
1943 static inline void xs_reclassify_socket(int family, struct socket *sock)
1944 {
1945 }
1946 #endif
1947 
1948 static void xs_dummy_setup_socket(struct work_struct *work)
1949 {
1950 }
1951 
1952 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1953 		struct sock_xprt *transport, int family, int type,
1954 		int protocol, bool reuseport)
1955 {
1956 	struct socket *sock;
1957 	int err;
1958 
1959 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1960 	if (err < 0) {
1961 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1962 				protocol, -err);
1963 		goto out;
1964 	}
1965 	xs_reclassify_socket(family, sock);
1966 
1967 	if (reuseport)
1968 		xs_sock_set_reuseport(sock);
1969 
1970 	err = xs_bind(transport, sock);
1971 	if (err) {
1972 		sock_release(sock);
1973 		goto out;
1974 	}
1975 
1976 	return sock;
1977 out:
1978 	return ERR_PTR(err);
1979 }
1980 
1981 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1982 				      struct socket *sock)
1983 {
1984 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1985 									xprt);
1986 
1987 	if (!transport->inet) {
1988 		struct sock *sk = sock->sk;
1989 
1990 		write_lock_bh(&sk->sk_callback_lock);
1991 
1992 		xs_save_old_callbacks(transport, sk);
1993 
1994 		sk->sk_user_data = xprt;
1995 		sk->sk_data_ready = xs_data_ready;
1996 		sk->sk_write_space = xs_udp_write_space;
1997 		sock_set_flag(sk, SOCK_FASYNC);
1998 		sk->sk_error_report = xs_error_report;
1999 		sk->sk_allocation = GFP_NOIO;
2000 
2001 		xprt_clear_connected(xprt);
2002 
2003 		/* Reset to new socket */
2004 		transport->sock = sock;
2005 		transport->inet = sk;
2006 
2007 		write_unlock_bh(&sk->sk_callback_lock);
2008 	}
2009 
2010 	/* Tell the socket layer to start connecting... */
2011 	xprt->stat.connect_count++;
2012 	xprt->stat.connect_start = jiffies;
2013 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
2014 }
2015 
2016 /**
2017  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
2018  * @transport: socket transport to connect
2019  */
2020 static int xs_local_setup_socket(struct sock_xprt *transport)
2021 {
2022 	struct rpc_xprt *xprt = &transport->xprt;
2023 	struct socket *sock;
2024 	int status = -EIO;
2025 
2026 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
2027 					SOCK_STREAM, 0, &sock, 1);
2028 	if (status < 0) {
2029 		dprintk("RPC:       can't create AF_LOCAL "
2030 			"transport socket (%d).\n", -status);
2031 		goto out;
2032 	}
2033 	xs_reclassify_socket(AF_LOCAL, sock);
2034 
2035 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
2036 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2037 
2038 	status = xs_local_finish_connecting(xprt, sock);
2039 	trace_rpc_socket_connect(xprt, sock, status);
2040 	switch (status) {
2041 	case 0:
2042 		dprintk("RPC:       xprt %p connected to %s\n",
2043 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2044 		xprt_set_connected(xprt);
2045 	case -ENOBUFS:
2046 		break;
2047 	case -ENOENT:
2048 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
2049 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2050 		break;
2051 	case -ECONNREFUSED:
2052 		dprintk("RPC:       xprt %p: connection refused for %s\n",
2053 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2054 		break;
2055 	default:
2056 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
2057 				__func__, -status,
2058 				xprt->address_strings[RPC_DISPLAY_ADDR]);
2059 	}
2060 
2061 out:
2062 	xprt_clear_connecting(xprt);
2063 	xprt_wake_pending_tasks(xprt, status);
2064 	return status;
2065 }
2066 
2067 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2068 {
2069 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2070 	int ret;
2071 
2072 	 if (RPC_IS_ASYNC(task)) {
2073 		/*
2074 		 * We want the AF_LOCAL connect to be resolved in the
2075 		 * filesystem namespace of the process making the rpc
2076 		 * call.  Thus we connect synchronously.
2077 		 *
2078 		 * If we want to support asynchronous AF_LOCAL calls,
2079 		 * we'll need to figure out how to pass a namespace to
2080 		 * connect.
2081 		 */
2082 		rpc_exit(task, -ENOTCONN);
2083 		return;
2084 	}
2085 	ret = xs_local_setup_socket(transport);
2086 	if (ret && !RPC_IS_SOFTCONN(task))
2087 		msleep_interruptible(15000);
2088 }
2089 
2090 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2091 /*
2092  * Note that this should be called with XPRT_LOCKED held (or when we otherwise
2093  * know that we have exclusive access to the socket), to guard against
2094  * races with xs_reset_transport.
2095  */
2096 static void xs_set_memalloc(struct rpc_xprt *xprt)
2097 {
2098 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2099 			xprt);
2100 
2101 	/*
2102 	 * If there's no sock, then we have nothing to set. The
2103 	 * reconnecting process will get it for us.
2104 	 */
2105 	if (!transport->inet)
2106 		return;
2107 	if (atomic_read(&xprt->swapper))
2108 		sk_set_memalloc(transport->inet);
2109 }
2110 
2111 /**
2112  * xs_enable_swap - Tag this transport as being used for swap.
2113  * @xprt: transport to tag
2114  *
2115  * Take a reference to this transport on behalf of the rpc_clnt, and
2116  * optionally mark it for swapping if it wasn't already.
2117  */
2118 static int
2119 xs_enable_swap(struct rpc_xprt *xprt)
2120 {
2121 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2122 
2123 	if (atomic_inc_return(&xprt->swapper) != 1)
2124 		return 0;
2125 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2126 		return -ERESTARTSYS;
2127 	if (xs->inet)
2128 		sk_set_memalloc(xs->inet);
2129 	xprt_release_xprt(xprt, NULL);
2130 	return 0;
2131 }
2132 
2133 /**
2134  * xs_disable_swap - Untag this transport as being used for swap.
2135  * @xprt: transport to tag
2136  *
2137  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2138  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2139  */
2140 static void
2141 xs_disable_swap(struct rpc_xprt *xprt)
2142 {
2143 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2144 
2145 	if (!atomic_dec_and_test(&xprt->swapper))
2146 		return;
2147 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2148 		return;
2149 	if (xs->inet)
2150 		sk_clear_memalloc(xs->inet);
2151 	xprt_release_xprt(xprt, NULL);
2152 }
2153 #else
2154 static void xs_set_memalloc(struct rpc_xprt *xprt)
2155 {
2156 }
2157 
2158 static int
2159 xs_enable_swap(struct rpc_xprt *xprt)
2160 {
2161 	return -EINVAL;
2162 }
2163 
2164 static void
2165 xs_disable_swap(struct rpc_xprt *xprt)
2166 {
2167 }
2168 #endif
2169 
2170 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2171 {
2172 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2173 
2174 	if (!transport->inet) {
2175 		struct sock *sk = sock->sk;
2176 
2177 		write_lock_bh(&sk->sk_callback_lock);
2178 
2179 		xs_save_old_callbacks(transport, sk);
2180 
2181 		sk->sk_user_data = xprt;
2182 		sk->sk_data_ready = xs_data_ready;
2183 		sk->sk_write_space = xs_udp_write_space;
2184 		sock_set_flag(sk, SOCK_FASYNC);
2185 		sk->sk_allocation = GFP_NOIO;
2186 
2187 		xprt_set_connected(xprt);
2188 
2189 		/* Reset to new socket */
2190 		transport->sock = sock;
2191 		transport->inet = sk;
2192 
2193 		xs_set_memalloc(xprt);
2194 
2195 		write_unlock_bh(&sk->sk_callback_lock);
2196 	}
2197 	xs_udp_do_set_buffer_size(xprt);
2198 
2199 	xprt->stat.connect_start = jiffies;
2200 }
2201 
2202 static void xs_udp_setup_socket(struct work_struct *work)
2203 {
2204 	struct sock_xprt *transport =
2205 		container_of(work, struct sock_xprt, connect_worker.work);
2206 	struct rpc_xprt *xprt = &transport->xprt;
2207 	struct socket *sock;
2208 	int status = -EIO;
2209 
2210 	sock = xs_create_sock(xprt, transport,
2211 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2212 			IPPROTO_UDP, false);
2213 	if (IS_ERR(sock))
2214 		goto out;
2215 
2216 	dprintk("RPC:       worker connecting xprt %p via %s to "
2217 				"%s (port %s)\n", xprt,
2218 			xprt->address_strings[RPC_DISPLAY_PROTO],
2219 			xprt->address_strings[RPC_DISPLAY_ADDR],
2220 			xprt->address_strings[RPC_DISPLAY_PORT]);
2221 
2222 	xs_udp_finish_connecting(xprt, sock);
2223 	trace_rpc_socket_connect(xprt, sock, 0);
2224 	status = 0;
2225 out:
2226 	xprt_unlock_connect(xprt, transport);
2227 	xprt_clear_connecting(xprt);
2228 	xprt_wake_pending_tasks(xprt, status);
2229 }
2230 
2231 /**
2232  * xs_tcp_shutdown - gracefully shut down a TCP socket
2233  * @xprt: transport
2234  *
2235  * Initiates a graceful shutdown of the TCP socket by calling the
2236  * equivalent of shutdown(SHUT_RDWR);
2237  */
2238 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2239 {
2240 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2241 	struct socket *sock = transport->sock;
2242 
2243 	if (sock == NULL)
2244 		return;
2245 	if (xprt_connected(xprt)) {
2246 		kernel_sock_shutdown(sock, SHUT_RDWR);
2247 		trace_rpc_socket_shutdown(xprt, sock);
2248 	} else
2249 		xs_reset_transport(transport);
2250 }
2251 
2252 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2253 		struct socket *sock)
2254 {
2255 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2256 	unsigned int keepidle;
2257 	unsigned int keepcnt;
2258 	unsigned int opt_on = 1;
2259 	unsigned int timeo;
2260 
2261 	spin_lock_bh(&xprt->transport_lock);
2262 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2263 	keepcnt = xprt->timeout->to_retries + 1;
2264 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2265 		(xprt->timeout->to_retries + 1);
2266 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2267 	spin_unlock_bh(&xprt->transport_lock);
2268 
2269 	/* TCP Keepalive options */
2270 	kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
2271 			(char *)&opt_on, sizeof(opt_on));
2272 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
2273 			(char *)&keepidle, sizeof(keepidle));
2274 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
2275 			(char *)&keepidle, sizeof(keepidle));
2276 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
2277 			(char *)&keepcnt, sizeof(keepcnt));
2278 
2279 	/* TCP user timeout (see RFC5482) */
2280 	kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
2281 			(char *)&timeo, sizeof(timeo));
2282 }
2283 
2284 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2285 		unsigned long connect_timeout,
2286 		unsigned long reconnect_timeout)
2287 {
2288 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2289 	struct rpc_timeout to;
2290 	unsigned long initval;
2291 
2292 	spin_lock_bh(&xprt->transport_lock);
2293 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2294 		xprt->max_reconnect_timeout = reconnect_timeout;
2295 	if (connect_timeout < xprt->connect_timeout) {
2296 		memcpy(&to, xprt->timeout, sizeof(to));
2297 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2298 		/* Arbitrary lower limit */
2299 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2300 			initval = XS_TCP_INIT_REEST_TO << 1;
2301 		to.to_initval = initval;
2302 		to.to_maxval = initval;
2303 		memcpy(&transport->tcp_timeout, &to,
2304 				sizeof(transport->tcp_timeout));
2305 		xprt->timeout = &transport->tcp_timeout;
2306 		xprt->connect_timeout = connect_timeout;
2307 	}
2308 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2309 	spin_unlock_bh(&xprt->transport_lock);
2310 }
2311 
2312 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2313 {
2314 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2315 	int ret = -ENOTCONN;
2316 
2317 	if (!transport->inet) {
2318 		struct sock *sk = sock->sk;
2319 		unsigned int addr_pref = IPV6_PREFER_SRC_PUBLIC;
2320 
2321 		/* Avoid temporary address, they are bad for long-lived
2322 		 * connections such as NFS mounts.
2323 		 * RFC4941, section 3.6 suggests that:
2324 		 *    Individual applications, which have specific
2325 		 *    knowledge about the normal duration of connections,
2326 		 *    MAY override this as appropriate.
2327 		 */
2328 		kernel_setsockopt(sock, SOL_IPV6, IPV6_ADDR_PREFERENCES,
2329 				(char *)&addr_pref, sizeof(addr_pref));
2330 
2331 		xs_tcp_set_socket_timeouts(xprt, sock);
2332 
2333 		write_lock_bh(&sk->sk_callback_lock);
2334 
2335 		xs_save_old_callbacks(transport, sk);
2336 
2337 		sk->sk_user_data = xprt;
2338 		sk->sk_data_ready = xs_data_ready;
2339 		sk->sk_state_change = xs_tcp_state_change;
2340 		sk->sk_write_space = xs_tcp_write_space;
2341 		sock_set_flag(sk, SOCK_FASYNC);
2342 		sk->sk_error_report = xs_error_report;
2343 		sk->sk_allocation = GFP_NOIO;
2344 
2345 		/* socket options */
2346 		sock_reset_flag(sk, SOCK_LINGER);
2347 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2348 
2349 		xprt_clear_connected(xprt);
2350 
2351 		/* Reset to new socket */
2352 		transport->sock = sock;
2353 		transport->inet = sk;
2354 
2355 		write_unlock_bh(&sk->sk_callback_lock);
2356 	}
2357 
2358 	if (!xprt_bound(xprt))
2359 		goto out;
2360 
2361 	xs_set_memalloc(xprt);
2362 
2363 	/* Tell the socket layer to start connecting... */
2364 	xprt->stat.connect_count++;
2365 	xprt->stat.connect_start = jiffies;
2366 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2367 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2368 	switch (ret) {
2369 	case 0:
2370 		xs_set_srcport(transport, sock);
2371 	case -EINPROGRESS:
2372 		/* SYN_SENT! */
2373 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2374 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2375 		break;
2376 	case -EADDRNOTAVAIL:
2377 		/* Source port number is unavailable. Try a new one! */
2378 		transport->srcport = 0;
2379 	}
2380 out:
2381 	return ret;
2382 }
2383 
2384 /**
2385  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2386  *
2387  * Invoked by a work queue tasklet.
2388  */
2389 static void xs_tcp_setup_socket(struct work_struct *work)
2390 {
2391 	struct sock_xprt *transport =
2392 		container_of(work, struct sock_xprt, connect_worker.work);
2393 	struct socket *sock = transport->sock;
2394 	struct rpc_xprt *xprt = &transport->xprt;
2395 	int status = -EIO;
2396 
2397 	if (!sock) {
2398 		sock = xs_create_sock(xprt, transport,
2399 				xs_addr(xprt)->sa_family, SOCK_STREAM,
2400 				IPPROTO_TCP, true);
2401 		if (IS_ERR(sock)) {
2402 			status = PTR_ERR(sock);
2403 			goto out;
2404 		}
2405 	}
2406 
2407 	dprintk("RPC:       worker connecting xprt %p via %s to "
2408 				"%s (port %s)\n", xprt,
2409 			xprt->address_strings[RPC_DISPLAY_PROTO],
2410 			xprt->address_strings[RPC_DISPLAY_ADDR],
2411 			xprt->address_strings[RPC_DISPLAY_PORT]);
2412 
2413 	status = xs_tcp_finish_connecting(xprt, sock);
2414 	trace_rpc_socket_connect(xprt, sock, status);
2415 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2416 			xprt, -status, xprt_connected(xprt),
2417 			sock->sk->sk_state);
2418 	switch (status) {
2419 	default:
2420 		printk("%s: connect returned unhandled error %d\n",
2421 			__func__, status);
2422 	case -EADDRNOTAVAIL:
2423 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2424 		 * and retry
2425 		 */
2426 		xs_tcp_force_close(xprt);
2427 		break;
2428 	case 0:
2429 	case -EINPROGRESS:
2430 	case -EALREADY:
2431 		xprt_unlock_connect(xprt, transport);
2432 		return;
2433 	case -EINVAL:
2434 		/* Happens, for instance, if the user specified a link
2435 		 * local IPv6 address without a scope-id.
2436 		 */
2437 	case -ECONNREFUSED:
2438 	case -ECONNRESET:
2439 	case -ENETUNREACH:
2440 	case -EADDRINUSE:
2441 	case -ENOBUFS:
2442 		/*
2443 		 * xs_tcp_force_close() wakes tasks with -EIO.
2444 		 * We need to wake them first to ensure the
2445 		 * correct error code.
2446 		 */
2447 		xprt_wake_pending_tasks(xprt, status);
2448 		xs_tcp_force_close(xprt);
2449 		goto out;
2450 	}
2451 	status = -EAGAIN;
2452 out:
2453 	xprt_unlock_connect(xprt, transport);
2454 	xprt_clear_connecting(xprt);
2455 	xprt_wake_pending_tasks(xprt, status);
2456 }
2457 
2458 static unsigned long xs_reconnect_delay(const struct rpc_xprt *xprt)
2459 {
2460 	unsigned long start, now = jiffies;
2461 
2462 	start = xprt->stat.connect_start + xprt->reestablish_timeout;
2463 	if (time_after(start, now))
2464 		return start - now;
2465 	return 0;
2466 }
2467 
2468 static void xs_reconnect_backoff(struct rpc_xprt *xprt)
2469 {
2470 	xprt->reestablish_timeout <<= 1;
2471 	if (xprt->reestablish_timeout > xprt->max_reconnect_timeout)
2472 		xprt->reestablish_timeout = xprt->max_reconnect_timeout;
2473 	if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2474 		xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2475 }
2476 
2477 /**
2478  * xs_connect - connect a socket to a remote endpoint
2479  * @xprt: pointer to transport structure
2480  * @task: address of RPC task that manages state of connect request
2481  *
2482  * TCP: If the remote end dropped the connection, delay reconnecting.
2483  *
2484  * UDP socket connects are synchronous, but we use a work queue anyway
2485  * to guarantee that even unprivileged user processes can set up a
2486  * socket on a privileged port.
2487  *
2488  * If a UDP socket connect fails, the delay behavior here prevents
2489  * retry floods (hard mounts).
2490  */
2491 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2492 {
2493 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2494 	unsigned long delay = 0;
2495 
2496 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2497 
2498 	if (transport->sock != NULL) {
2499 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2500 				"seconds\n",
2501 				xprt, xprt->reestablish_timeout / HZ);
2502 
2503 		/* Start by resetting any existing state */
2504 		xs_reset_transport(transport);
2505 
2506 		delay = xs_reconnect_delay(xprt);
2507 		xs_reconnect_backoff(xprt);
2508 
2509 	} else
2510 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2511 
2512 	queue_delayed_work(xprtiod_workqueue,
2513 			&transport->connect_worker,
2514 			delay);
2515 }
2516 
2517 /**
2518  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2519  * @xprt: rpc_xprt struct containing statistics
2520  * @seq: output file
2521  *
2522  */
2523 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2524 {
2525 	long idle_time = 0;
2526 
2527 	if (xprt_connected(xprt))
2528 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2529 
2530 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2531 			"%llu %llu %lu %llu %llu\n",
2532 			xprt->stat.bind_count,
2533 			xprt->stat.connect_count,
2534 			xprt->stat.connect_time,
2535 			idle_time,
2536 			xprt->stat.sends,
2537 			xprt->stat.recvs,
2538 			xprt->stat.bad_xids,
2539 			xprt->stat.req_u,
2540 			xprt->stat.bklog_u,
2541 			xprt->stat.max_slots,
2542 			xprt->stat.sending_u,
2543 			xprt->stat.pending_u);
2544 }
2545 
2546 /**
2547  * xs_udp_print_stats - display UDP socket-specifc stats
2548  * @xprt: rpc_xprt struct containing statistics
2549  * @seq: output file
2550  *
2551  */
2552 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2553 {
2554 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2555 
2556 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2557 			"%lu %llu %llu\n",
2558 			transport->srcport,
2559 			xprt->stat.bind_count,
2560 			xprt->stat.sends,
2561 			xprt->stat.recvs,
2562 			xprt->stat.bad_xids,
2563 			xprt->stat.req_u,
2564 			xprt->stat.bklog_u,
2565 			xprt->stat.max_slots,
2566 			xprt->stat.sending_u,
2567 			xprt->stat.pending_u);
2568 }
2569 
2570 /**
2571  * xs_tcp_print_stats - display TCP socket-specifc stats
2572  * @xprt: rpc_xprt struct containing statistics
2573  * @seq: output file
2574  *
2575  */
2576 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2577 {
2578 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2579 	long idle_time = 0;
2580 
2581 	if (xprt_connected(xprt))
2582 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2583 
2584 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2585 			"%llu %llu %lu %llu %llu\n",
2586 			transport->srcport,
2587 			xprt->stat.bind_count,
2588 			xprt->stat.connect_count,
2589 			xprt->stat.connect_time,
2590 			idle_time,
2591 			xprt->stat.sends,
2592 			xprt->stat.recvs,
2593 			xprt->stat.bad_xids,
2594 			xprt->stat.req_u,
2595 			xprt->stat.bklog_u,
2596 			xprt->stat.max_slots,
2597 			xprt->stat.sending_u,
2598 			xprt->stat.pending_u);
2599 }
2600 
2601 /*
2602  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2603  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2604  * to use the server side send routines.
2605  */
2606 static int bc_malloc(struct rpc_task *task)
2607 {
2608 	struct rpc_rqst *rqst = task->tk_rqstp;
2609 	size_t size = rqst->rq_callsize;
2610 	struct page *page;
2611 	struct rpc_buffer *buf;
2612 
2613 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2614 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2615 			  size);
2616 		return -EINVAL;
2617 	}
2618 
2619 	page = alloc_page(GFP_KERNEL);
2620 	if (!page)
2621 		return -ENOMEM;
2622 
2623 	buf = page_address(page);
2624 	buf->len = PAGE_SIZE;
2625 
2626 	rqst->rq_buffer = buf->data;
2627 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2628 	return 0;
2629 }
2630 
2631 /*
2632  * Free the space allocated in the bc_alloc routine
2633  */
2634 static void bc_free(struct rpc_task *task)
2635 {
2636 	void *buffer = task->tk_rqstp->rq_buffer;
2637 	struct rpc_buffer *buf;
2638 
2639 	buf = container_of(buffer, struct rpc_buffer, data);
2640 	free_page((unsigned long)buf);
2641 }
2642 
2643 /*
2644  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2645  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2646  */
2647 static int bc_sendto(struct rpc_rqst *req)
2648 {
2649 	int len;
2650 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2651 	struct rpc_xprt *xprt = req->rq_xprt;
2652 	struct sock_xprt *transport =
2653 				container_of(xprt, struct sock_xprt, xprt);
2654 	struct socket *sock = transport->sock;
2655 	unsigned long headoff;
2656 	unsigned long tailoff;
2657 
2658 	xs_encode_stream_record_marker(xbufp);
2659 
2660 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2661 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2662 	len = svc_send_common(sock, xbufp,
2663 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2664 			      xbufp->tail[0].iov_base, tailoff);
2665 
2666 	if (len != xbufp->len) {
2667 		printk(KERN_NOTICE "Error sending entire callback!\n");
2668 		len = -EAGAIN;
2669 	}
2670 
2671 	return len;
2672 }
2673 
2674 /*
2675  * The send routine. Borrows from svc_send
2676  */
2677 static int bc_send_request(struct rpc_task *task)
2678 {
2679 	struct rpc_rqst *req = task->tk_rqstp;
2680 	struct svc_xprt	*xprt;
2681 	int len;
2682 
2683 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2684 	/*
2685 	 * Get the server socket associated with this callback xprt
2686 	 */
2687 	xprt = req->rq_xprt->bc_xprt;
2688 
2689 	/*
2690 	 * Grab the mutex to serialize data as the connection is shared
2691 	 * with the fore channel
2692 	 */
2693 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2694 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2695 		if (!mutex_trylock(&xprt->xpt_mutex))
2696 			return -EAGAIN;
2697 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2698 	}
2699 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2700 		len = -ENOTCONN;
2701 	else
2702 		len = bc_sendto(req);
2703 	mutex_unlock(&xprt->xpt_mutex);
2704 
2705 	if (len > 0)
2706 		len = 0;
2707 
2708 	return len;
2709 }
2710 
2711 /*
2712  * The close routine. Since this is client initiated, we do nothing
2713  */
2714 
2715 static void bc_close(struct rpc_xprt *xprt)
2716 {
2717 }
2718 
2719 /*
2720  * The xprt destroy routine. Again, because this connection is client
2721  * initiated, we do nothing
2722  */
2723 
2724 static void bc_destroy(struct rpc_xprt *xprt)
2725 {
2726 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2727 
2728 	xs_xprt_free(xprt);
2729 	module_put(THIS_MODULE);
2730 }
2731 
2732 static const struct rpc_xprt_ops xs_local_ops = {
2733 	.reserve_xprt		= xprt_reserve_xprt,
2734 	.release_xprt		= xs_tcp_release_xprt,
2735 	.alloc_slot		= xprt_alloc_slot,
2736 	.rpcbind		= xs_local_rpcbind,
2737 	.set_port		= xs_local_set_port,
2738 	.connect		= xs_local_connect,
2739 	.buf_alloc		= rpc_malloc,
2740 	.buf_free		= rpc_free,
2741 	.send_request		= xs_local_send_request,
2742 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2743 	.close			= xs_close,
2744 	.destroy		= xs_destroy,
2745 	.print_stats		= xs_local_print_stats,
2746 	.enable_swap		= xs_enable_swap,
2747 	.disable_swap		= xs_disable_swap,
2748 };
2749 
2750 static const struct rpc_xprt_ops xs_udp_ops = {
2751 	.set_buffer_size	= xs_udp_set_buffer_size,
2752 	.reserve_xprt		= xprt_reserve_xprt_cong,
2753 	.release_xprt		= xprt_release_xprt_cong,
2754 	.alloc_slot		= xprt_alloc_slot,
2755 	.rpcbind		= rpcb_getport_async,
2756 	.set_port		= xs_set_port,
2757 	.connect		= xs_connect,
2758 	.buf_alloc		= rpc_malloc,
2759 	.buf_free		= rpc_free,
2760 	.send_request		= xs_udp_send_request,
2761 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2762 	.timer			= xs_udp_timer,
2763 	.release_request	= xprt_release_rqst_cong,
2764 	.close			= xs_close,
2765 	.destroy		= xs_destroy,
2766 	.print_stats		= xs_udp_print_stats,
2767 	.enable_swap		= xs_enable_swap,
2768 	.disable_swap		= xs_disable_swap,
2769 	.inject_disconnect	= xs_inject_disconnect,
2770 };
2771 
2772 static const struct rpc_xprt_ops xs_tcp_ops = {
2773 	.reserve_xprt		= xprt_reserve_xprt,
2774 	.release_xprt		= xs_tcp_release_xprt,
2775 	.alloc_slot		= xprt_lock_and_alloc_slot,
2776 	.rpcbind		= rpcb_getport_async,
2777 	.set_port		= xs_set_port,
2778 	.connect		= xs_connect,
2779 	.buf_alloc		= rpc_malloc,
2780 	.buf_free		= rpc_free,
2781 	.send_request		= xs_tcp_send_request,
2782 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2783 	.close			= xs_tcp_shutdown,
2784 	.destroy		= xs_destroy,
2785 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2786 	.print_stats		= xs_tcp_print_stats,
2787 	.enable_swap		= xs_enable_swap,
2788 	.disable_swap		= xs_disable_swap,
2789 	.inject_disconnect	= xs_inject_disconnect,
2790 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2791 	.bc_setup		= xprt_setup_bc,
2792 	.bc_up			= xs_tcp_bc_up,
2793 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2794 	.bc_free_rqst		= xprt_free_bc_rqst,
2795 	.bc_destroy		= xprt_destroy_bc,
2796 #endif
2797 };
2798 
2799 /*
2800  * The rpc_xprt_ops for the server backchannel
2801  */
2802 
2803 static const struct rpc_xprt_ops bc_tcp_ops = {
2804 	.reserve_xprt		= xprt_reserve_xprt,
2805 	.release_xprt		= xprt_release_xprt,
2806 	.alloc_slot		= xprt_alloc_slot,
2807 	.buf_alloc		= bc_malloc,
2808 	.buf_free		= bc_free,
2809 	.send_request		= bc_send_request,
2810 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2811 	.close			= bc_close,
2812 	.destroy		= bc_destroy,
2813 	.print_stats		= xs_tcp_print_stats,
2814 	.enable_swap		= xs_enable_swap,
2815 	.disable_swap		= xs_disable_swap,
2816 	.inject_disconnect	= xs_inject_disconnect,
2817 };
2818 
2819 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2820 {
2821 	static const struct sockaddr_in sin = {
2822 		.sin_family		= AF_INET,
2823 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2824 	};
2825 	static const struct sockaddr_in6 sin6 = {
2826 		.sin6_family		= AF_INET6,
2827 		.sin6_addr		= IN6ADDR_ANY_INIT,
2828 	};
2829 
2830 	switch (family) {
2831 	case AF_LOCAL:
2832 		break;
2833 	case AF_INET:
2834 		memcpy(sap, &sin, sizeof(sin));
2835 		break;
2836 	case AF_INET6:
2837 		memcpy(sap, &sin6, sizeof(sin6));
2838 		break;
2839 	default:
2840 		dprintk("RPC:       %s: Bad address family\n", __func__);
2841 		return -EAFNOSUPPORT;
2842 	}
2843 	return 0;
2844 }
2845 
2846 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2847 				      unsigned int slot_table_size,
2848 				      unsigned int max_slot_table_size)
2849 {
2850 	struct rpc_xprt *xprt;
2851 	struct sock_xprt *new;
2852 
2853 	if (args->addrlen > sizeof(xprt->addr)) {
2854 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2855 		return ERR_PTR(-EBADF);
2856 	}
2857 
2858 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2859 			max_slot_table_size);
2860 	if (xprt == NULL) {
2861 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2862 				"rpc_xprt\n");
2863 		return ERR_PTR(-ENOMEM);
2864 	}
2865 
2866 	new = container_of(xprt, struct sock_xprt, xprt);
2867 	mutex_init(&new->recv_mutex);
2868 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2869 	xprt->addrlen = args->addrlen;
2870 	if (args->srcaddr)
2871 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2872 	else {
2873 		int err;
2874 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2875 					(struct sockaddr *)&new->srcaddr);
2876 		if (err != 0) {
2877 			xprt_free(xprt);
2878 			return ERR_PTR(err);
2879 		}
2880 	}
2881 
2882 	return xprt;
2883 }
2884 
2885 static const struct rpc_timeout xs_local_default_timeout = {
2886 	.to_initval = 10 * HZ,
2887 	.to_maxval = 10 * HZ,
2888 	.to_retries = 2,
2889 };
2890 
2891 /**
2892  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2893  * @args: rpc transport creation arguments
2894  *
2895  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2896  */
2897 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2898 {
2899 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2900 	struct sock_xprt *transport;
2901 	struct rpc_xprt *xprt;
2902 	struct rpc_xprt *ret;
2903 
2904 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2905 			xprt_max_tcp_slot_table_entries);
2906 	if (IS_ERR(xprt))
2907 		return xprt;
2908 	transport = container_of(xprt, struct sock_xprt, xprt);
2909 
2910 	xprt->prot = 0;
2911 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2912 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2913 
2914 	xprt->bind_timeout = XS_BIND_TO;
2915 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2916 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2917 
2918 	xprt->ops = &xs_local_ops;
2919 	xprt->timeout = &xs_local_default_timeout;
2920 
2921 	INIT_WORK(&transport->recv_worker, xs_local_data_receive_workfn);
2922 	INIT_DELAYED_WORK(&transport->connect_worker,
2923 			xs_dummy_setup_socket);
2924 
2925 	switch (sun->sun_family) {
2926 	case AF_LOCAL:
2927 		if (sun->sun_path[0] != '/') {
2928 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2929 					sun->sun_path);
2930 			ret = ERR_PTR(-EINVAL);
2931 			goto out_err;
2932 		}
2933 		xprt_set_bound(xprt);
2934 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2935 		ret = ERR_PTR(xs_local_setup_socket(transport));
2936 		if (ret)
2937 			goto out_err;
2938 		break;
2939 	default:
2940 		ret = ERR_PTR(-EAFNOSUPPORT);
2941 		goto out_err;
2942 	}
2943 
2944 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2945 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2946 
2947 	if (try_module_get(THIS_MODULE))
2948 		return xprt;
2949 	ret = ERR_PTR(-EINVAL);
2950 out_err:
2951 	xs_xprt_free(xprt);
2952 	return ret;
2953 }
2954 
2955 static const struct rpc_timeout xs_udp_default_timeout = {
2956 	.to_initval = 5 * HZ,
2957 	.to_maxval = 30 * HZ,
2958 	.to_increment = 5 * HZ,
2959 	.to_retries = 5,
2960 };
2961 
2962 /**
2963  * xs_setup_udp - Set up transport to use a UDP socket
2964  * @args: rpc transport creation arguments
2965  *
2966  */
2967 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2968 {
2969 	struct sockaddr *addr = args->dstaddr;
2970 	struct rpc_xprt *xprt;
2971 	struct sock_xprt *transport;
2972 	struct rpc_xprt *ret;
2973 
2974 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2975 			xprt_udp_slot_table_entries);
2976 	if (IS_ERR(xprt))
2977 		return xprt;
2978 	transport = container_of(xprt, struct sock_xprt, xprt);
2979 
2980 	xprt->prot = IPPROTO_UDP;
2981 	xprt->tsh_size = 0;
2982 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2983 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2984 
2985 	xprt->bind_timeout = XS_BIND_TO;
2986 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2987 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2988 
2989 	xprt->ops = &xs_udp_ops;
2990 
2991 	xprt->timeout = &xs_udp_default_timeout;
2992 
2993 	INIT_WORK(&transport->recv_worker, xs_udp_data_receive_workfn);
2994 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
2995 
2996 	switch (addr->sa_family) {
2997 	case AF_INET:
2998 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2999 			xprt_set_bound(xprt);
3000 
3001 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
3002 		break;
3003 	case AF_INET6:
3004 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3005 			xprt_set_bound(xprt);
3006 
3007 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
3008 		break;
3009 	default:
3010 		ret = ERR_PTR(-EAFNOSUPPORT);
3011 		goto out_err;
3012 	}
3013 
3014 	if (xprt_bound(xprt))
3015 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3016 				xprt->address_strings[RPC_DISPLAY_ADDR],
3017 				xprt->address_strings[RPC_DISPLAY_PORT],
3018 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3019 	else
3020 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3021 				xprt->address_strings[RPC_DISPLAY_ADDR],
3022 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3023 
3024 	if (try_module_get(THIS_MODULE))
3025 		return xprt;
3026 	ret = ERR_PTR(-EINVAL);
3027 out_err:
3028 	xs_xprt_free(xprt);
3029 	return ret;
3030 }
3031 
3032 static const struct rpc_timeout xs_tcp_default_timeout = {
3033 	.to_initval = 60 * HZ,
3034 	.to_maxval = 60 * HZ,
3035 	.to_retries = 2,
3036 };
3037 
3038 /**
3039  * xs_setup_tcp - Set up transport to use a TCP socket
3040  * @args: rpc transport creation arguments
3041  *
3042  */
3043 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
3044 {
3045 	struct sockaddr *addr = args->dstaddr;
3046 	struct rpc_xprt *xprt;
3047 	struct sock_xprt *transport;
3048 	struct rpc_xprt *ret;
3049 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
3050 
3051 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
3052 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
3053 
3054 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3055 			max_slot_table_size);
3056 	if (IS_ERR(xprt))
3057 		return xprt;
3058 	transport = container_of(xprt, struct sock_xprt, xprt);
3059 
3060 	xprt->prot = IPPROTO_TCP;
3061 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
3062 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3063 
3064 	xprt->bind_timeout = XS_BIND_TO;
3065 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
3066 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3067 
3068 	xprt->ops = &xs_tcp_ops;
3069 	xprt->timeout = &xs_tcp_default_timeout;
3070 
3071 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3072 	xprt->connect_timeout = xprt->timeout->to_initval *
3073 		(xprt->timeout->to_retries + 1);
3074 
3075 	INIT_WORK(&transport->recv_worker, xs_tcp_data_receive_workfn);
3076 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3077 
3078 	switch (addr->sa_family) {
3079 	case AF_INET:
3080 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3081 			xprt_set_bound(xprt);
3082 
3083 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3084 		break;
3085 	case AF_INET6:
3086 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3087 			xprt_set_bound(xprt);
3088 
3089 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3090 		break;
3091 	default:
3092 		ret = ERR_PTR(-EAFNOSUPPORT);
3093 		goto out_err;
3094 	}
3095 
3096 	if (xprt_bound(xprt))
3097 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3098 				xprt->address_strings[RPC_DISPLAY_ADDR],
3099 				xprt->address_strings[RPC_DISPLAY_PORT],
3100 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3101 	else
3102 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3103 				xprt->address_strings[RPC_DISPLAY_ADDR],
3104 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3105 
3106 	if (try_module_get(THIS_MODULE))
3107 		return xprt;
3108 	ret = ERR_PTR(-EINVAL);
3109 out_err:
3110 	xs_xprt_free(xprt);
3111 	return ret;
3112 }
3113 
3114 /**
3115  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3116  * @args: rpc transport creation arguments
3117  *
3118  */
3119 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3120 {
3121 	struct sockaddr *addr = args->dstaddr;
3122 	struct rpc_xprt *xprt;
3123 	struct sock_xprt *transport;
3124 	struct svc_sock *bc_sock;
3125 	struct rpc_xprt *ret;
3126 
3127 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3128 			xprt_tcp_slot_table_entries);
3129 	if (IS_ERR(xprt))
3130 		return xprt;
3131 	transport = container_of(xprt, struct sock_xprt, xprt);
3132 
3133 	xprt->prot = IPPROTO_TCP;
3134 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
3135 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3136 	xprt->timeout = &xs_tcp_default_timeout;
3137 
3138 	/* backchannel */
3139 	xprt_set_bound(xprt);
3140 	xprt->bind_timeout = 0;
3141 	xprt->reestablish_timeout = 0;
3142 	xprt->idle_timeout = 0;
3143 
3144 	xprt->ops = &bc_tcp_ops;
3145 
3146 	switch (addr->sa_family) {
3147 	case AF_INET:
3148 		xs_format_peer_addresses(xprt, "tcp",
3149 					 RPCBIND_NETID_TCP);
3150 		break;
3151 	case AF_INET6:
3152 		xs_format_peer_addresses(xprt, "tcp",
3153 				   RPCBIND_NETID_TCP6);
3154 		break;
3155 	default:
3156 		ret = ERR_PTR(-EAFNOSUPPORT);
3157 		goto out_err;
3158 	}
3159 
3160 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3161 			xprt->address_strings[RPC_DISPLAY_ADDR],
3162 			xprt->address_strings[RPC_DISPLAY_PORT],
3163 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3164 
3165 	/*
3166 	 * Once we've associated a backchannel xprt with a connection,
3167 	 * we want to keep it around as long as the connection lasts,
3168 	 * in case we need to start using it for a backchannel again;
3169 	 * this reference won't be dropped until bc_xprt is destroyed.
3170 	 */
3171 	xprt_get(xprt);
3172 	args->bc_xprt->xpt_bc_xprt = xprt;
3173 	xprt->bc_xprt = args->bc_xprt;
3174 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3175 	transport->sock = bc_sock->sk_sock;
3176 	transport->inet = bc_sock->sk_sk;
3177 
3178 	/*
3179 	 * Since we don't want connections for the backchannel, we set
3180 	 * the xprt status to connected
3181 	 */
3182 	xprt_set_connected(xprt);
3183 
3184 	if (try_module_get(THIS_MODULE))
3185 		return xprt;
3186 
3187 	args->bc_xprt->xpt_bc_xprt = NULL;
3188 	args->bc_xprt->xpt_bc_xps = NULL;
3189 	xprt_put(xprt);
3190 	ret = ERR_PTR(-EINVAL);
3191 out_err:
3192 	xs_xprt_free(xprt);
3193 	return ret;
3194 }
3195 
3196 static struct xprt_class	xs_local_transport = {
3197 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3198 	.name		= "named UNIX socket",
3199 	.owner		= THIS_MODULE,
3200 	.ident		= XPRT_TRANSPORT_LOCAL,
3201 	.setup		= xs_setup_local,
3202 };
3203 
3204 static struct xprt_class	xs_udp_transport = {
3205 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3206 	.name		= "udp",
3207 	.owner		= THIS_MODULE,
3208 	.ident		= XPRT_TRANSPORT_UDP,
3209 	.setup		= xs_setup_udp,
3210 };
3211 
3212 static struct xprt_class	xs_tcp_transport = {
3213 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3214 	.name		= "tcp",
3215 	.owner		= THIS_MODULE,
3216 	.ident		= XPRT_TRANSPORT_TCP,
3217 	.setup		= xs_setup_tcp,
3218 };
3219 
3220 static struct xprt_class	xs_bc_tcp_transport = {
3221 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3222 	.name		= "tcp NFSv4.1 backchannel",
3223 	.owner		= THIS_MODULE,
3224 	.ident		= XPRT_TRANSPORT_BC_TCP,
3225 	.setup		= xs_setup_bc_tcp,
3226 };
3227 
3228 /**
3229  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3230  *
3231  */
3232 int init_socket_xprt(void)
3233 {
3234 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3235 	if (!sunrpc_table_header)
3236 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
3237 #endif
3238 
3239 	xprt_register_transport(&xs_local_transport);
3240 	xprt_register_transport(&xs_udp_transport);
3241 	xprt_register_transport(&xs_tcp_transport);
3242 	xprt_register_transport(&xs_bc_tcp_transport);
3243 
3244 	return 0;
3245 }
3246 
3247 /**
3248  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3249  *
3250  */
3251 void cleanup_socket_xprt(void)
3252 {
3253 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3254 	if (sunrpc_table_header) {
3255 		unregister_sysctl_table(sunrpc_table_header);
3256 		sunrpc_table_header = NULL;
3257 	}
3258 #endif
3259 
3260 	xprt_unregister_transport(&xs_local_transport);
3261 	xprt_unregister_transport(&xs_udp_transport);
3262 	xprt_unregister_transport(&xs_tcp_transport);
3263 	xprt_unregister_transport(&xs_bc_tcp_transport);
3264 }
3265 
3266 static int param_set_uint_minmax(const char *val,
3267 		const struct kernel_param *kp,
3268 		unsigned int min, unsigned int max)
3269 {
3270 	unsigned int num;
3271 	int ret;
3272 
3273 	if (!val)
3274 		return -EINVAL;
3275 	ret = kstrtouint(val, 0, &num);
3276 	if (ret)
3277 		return ret;
3278 	if (num < min || num > max)
3279 		return -EINVAL;
3280 	*((unsigned int *)kp->arg) = num;
3281 	return 0;
3282 }
3283 
3284 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3285 {
3286 	if (kp->arg == &xprt_min_resvport)
3287 		return param_set_uint_minmax(val, kp,
3288 			RPC_MIN_RESVPORT,
3289 			xprt_max_resvport);
3290 	return param_set_uint_minmax(val, kp,
3291 			xprt_min_resvport,
3292 			RPC_MAX_RESVPORT);
3293 }
3294 
3295 static const struct kernel_param_ops param_ops_portnr = {
3296 	.set = param_set_portnr,
3297 	.get = param_get_uint,
3298 };
3299 
3300 #define param_check_portnr(name, p) \
3301 	__param_check(name, p, unsigned int);
3302 
3303 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3304 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3305 
3306 static int param_set_slot_table_size(const char *val,
3307 				     const struct kernel_param *kp)
3308 {
3309 	return param_set_uint_minmax(val, kp,
3310 			RPC_MIN_SLOT_TABLE,
3311 			RPC_MAX_SLOT_TABLE);
3312 }
3313 
3314 static const struct kernel_param_ops param_ops_slot_table_size = {
3315 	.set = param_set_slot_table_size,
3316 	.get = param_get_uint,
3317 };
3318 
3319 #define param_check_slot_table_size(name, p) \
3320 	__param_check(name, p, unsigned int);
3321 
3322 static int param_set_max_slot_table_size(const char *val,
3323 				     const struct kernel_param *kp)
3324 {
3325 	return param_set_uint_minmax(val, kp,
3326 			RPC_MIN_SLOT_TABLE,
3327 			RPC_MAX_SLOT_TABLE_LIMIT);
3328 }
3329 
3330 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3331 	.set = param_set_max_slot_table_size,
3332 	.get = param_get_uint,
3333 };
3334 
3335 #define param_check_max_slot_table_size(name, p) \
3336 	__param_check(name, p, unsigned int);
3337 
3338 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3339 		   slot_table_size, 0644);
3340 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3341 		   max_slot_table_size, 0644);
3342 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3343 		   slot_table_size, 0644);
3344 
3345