xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision 867a0e05)
1 /*
2  * linux/net/sunrpc/xprtsock.c
3  *
4  * Client-side transport implementation for sockets.
5  *
6  * TCP callback races fixes (C) 1998 Red Hat
7  * TCP send fixes (C) 1998 Red Hat
8  * TCP NFS related read + write fixes
9  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
10  *
11  * Rewrite of larges part of the code in order to stabilize TCP stuff.
12  * Fix behaviour when socket buffer is full.
13  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
14  *
15  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
16  *
17  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
18  *   <gilles.quillard@bull.net>
19  */
20 
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/capability.h>
26 #include <linux/pagemap.h>
27 #include <linux/errno.h>
28 #include <linux/socket.h>
29 #include <linux/in.h>
30 #include <linux/net.h>
31 #include <linux/mm.h>
32 #include <linux/un.h>
33 #include <linux/udp.h>
34 #include <linux/tcp.h>
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/addr.h>
37 #include <linux/sunrpc/sched.h>
38 #include <linux/sunrpc/svcsock.h>
39 #include <linux/sunrpc/xprtsock.h>
40 #include <linux/file.h>
41 #ifdef CONFIG_SUNRPC_BACKCHANNEL
42 #include <linux/sunrpc/bc_xprt.h>
43 #endif
44 
45 #include <net/sock.h>
46 #include <net/checksum.h>
47 #include <net/udp.h>
48 #include <net/tcp.h>
49 
50 #include <trace/events/sunrpc.h>
51 
52 #include "sunrpc.h"
53 
54 static void xs_close(struct rpc_xprt *xprt);
55 
56 /*
57  * xprtsock tunables
58  */
59 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
60 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
61 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
62 
63 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
64 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
65 
66 #define XS_TCP_LINGER_TO	(15U * HZ)
67 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
68 
69 /*
70  * We can register our own files under /proc/sys/sunrpc by
71  * calling register_sysctl_table() again.  The files in that
72  * directory become the union of all files registered there.
73  *
74  * We simply need to make sure that we don't collide with
75  * someone else's file names!
76  */
77 
78 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
79 
80 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
81 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
82 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
83 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
84 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
85 
86 static struct ctl_table_header *sunrpc_table_header;
87 
88 /*
89  * FIXME: changing the UDP slot table size should also resize the UDP
90  *        socket buffers for existing UDP transports
91  */
92 static struct ctl_table xs_tunables_table[] = {
93 	{
94 		.procname	= "udp_slot_table_entries",
95 		.data		= &xprt_udp_slot_table_entries,
96 		.maxlen		= sizeof(unsigned int),
97 		.mode		= 0644,
98 		.proc_handler	= proc_dointvec_minmax,
99 		.extra1		= &min_slot_table_size,
100 		.extra2		= &max_slot_table_size
101 	},
102 	{
103 		.procname	= "tcp_slot_table_entries",
104 		.data		= &xprt_tcp_slot_table_entries,
105 		.maxlen		= sizeof(unsigned int),
106 		.mode		= 0644,
107 		.proc_handler	= proc_dointvec_minmax,
108 		.extra1		= &min_slot_table_size,
109 		.extra2		= &max_slot_table_size
110 	},
111 	{
112 		.procname	= "tcp_max_slot_table_entries",
113 		.data		= &xprt_max_tcp_slot_table_entries,
114 		.maxlen		= sizeof(unsigned int),
115 		.mode		= 0644,
116 		.proc_handler	= proc_dointvec_minmax,
117 		.extra1		= &min_slot_table_size,
118 		.extra2		= &max_tcp_slot_table_limit
119 	},
120 	{
121 		.procname	= "min_resvport",
122 		.data		= &xprt_min_resvport,
123 		.maxlen		= sizeof(unsigned int),
124 		.mode		= 0644,
125 		.proc_handler	= proc_dointvec_minmax,
126 		.extra1		= &xprt_min_resvport_limit,
127 		.extra2		= &xprt_max_resvport_limit
128 	},
129 	{
130 		.procname	= "max_resvport",
131 		.data		= &xprt_max_resvport,
132 		.maxlen		= sizeof(unsigned int),
133 		.mode		= 0644,
134 		.proc_handler	= proc_dointvec_minmax,
135 		.extra1		= &xprt_min_resvport_limit,
136 		.extra2		= &xprt_max_resvport_limit
137 	},
138 	{
139 		.procname	= "tcp_fin_timeout",
140 		.data		= &xs_tcp_fin_timeout,
141 		.maxlen		= sizeof(xs_tcp_fin_timeout),
142 		.mode		= 0644,
143 		.proc_handler	= proc_dointvec_jiffies,
144 	},
145 	{ },
146 };
147 
148 static struct ctl_table sunrpc_table[] = {
149 	{
150 		.procname	= "sunrpc",
151 		.mode		= 0555,
152 		.child		= xs_tunables_table
153 	},
154 	{ },
155 };
156 
157 #endif
158 
159 /*
160  * Wait duration for a reply from the RPC portmapper.
161  */
162 #define XS_BIND_TO		(60U * HZ)
163 
164 /*
165  * Delay if a UDP socket connect error occurs.  This is most likely some
166  * kind of resource problem on the local host.
167  */
168 #define XS_UDP_REEST_TO		(2U * HZ)
169 
170 /*
171  * The reestablish timeout allows clients to delay for a bit before attempting
172  * to reconnect to a server that just dropped our connection.
173  *
174  * We implement an exponential backoff when trying to reestablish a TCP
175  * transport connection with the server.  Some servers like to drop a TCP
176  * connection when they are overworked, so we start with a short timeout and
177  * increase over time if the server is down or not responding.
178  */
179 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
180 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
181 
182 /*
183  * TCP idle timeout; client drops the transport socket if it is idle
184  * for this long.  Note that we also timeout UDP sockets to prevent
185  * holding port numbers when there is no RPC traffic.
186  */
187 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
188 
189 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
190 # undef  RPC_DEBUG_DATA
191 # define RPCDBG_FACILITY	RPCDBG_TRANS
192 #endif
193 
194 #ifdef RPC_DEBUG_DATA
195 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
196 {
197 	u8 *buf = (u8 *) packet;
198 	int j;
199 
200 	dprintk("RPC:       %s\n", msg);
201 	for (j = 0; j < count && j < 128; j += 4) {
202 		if (!(j & 31)) {
203 			if (j)
204 				dprintk("\n");
205 			dprintk("0x%04x ", j);
206 		}
207 		dprintk("%02x%02x%02x%02x ",
208 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
209 	}
210 	dprintk("\n");
211 }
212 #else
213 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
214 {
215 	/* NOP */
216 }
217 #endif
218 
219 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
220 {
221 	return (struct rpc_xprt *) sk->sk_user_data;
222 }
223 
224 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
225 {
226 	return (struct sockaddr *) &xprt->addr;
227 }
228 
229 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
230 {
231 	return (struct sockaddr_un *) &xprt->addr;
232 }
233 
234 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
235 {
236 	return (struct sockaddr_in *) &xprt->addr;
237 }
238 
239 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
240 {
241 	return (struct sockaddr_in6 *) &xprt->addr;
242 }
243 
244 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
245 {
246 	struct sockaddr *sap = xs_addr(xprt);
247 	struct sockaddr_in6 *sin6;
248 	struct sockaddr_in *sin;
249 	struct sockaddr_un *sun;
250 	char buf[128];
251 
252 	switch (sap->sa_family) {
253 	case AF_LOCAL:
254 		sun = xs_addr_un(xprt);
255 		strlcpy(buf, sun->sun_path, sizeof(buf));
256 		xprt->address_strings[RPC_DISPLAY_ADDR] =
257 						kstrdup(buf, GFP_KERNEL);
258 		break;
259 	case AF_INET:
260 		(void)rpc_ntop(sap, buf, sizeof(buf));
261 		xprt->address_strings[RPC_DISPLAY_ADDR] =
262 						kstrdup(buf, GFP_KERNEL);
263 		sin = xs_addr_in(xprt);
264 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
265 		break;
266 	case AF_INET6:
267 		(void)rpc_ntop(sap, buf, sizeof(buf));
268 		xprt->address_strings[RPC_DISPLAY_ADDR] =
269 						kstrdup(buf, GFP_KERNEL);
270 		sin6 = xs_addr_in6(xprt);
271 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
272 		break;
273 	default:
274 		BUG();
275 	}
276 
277 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
278 }
279 
280 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
281 {
282 	struct sockaddr *sap = xs_addr(xprt);
283 	char buf[128];
284 
285 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
286 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
287 
288 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
289 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
290 }
291 
292 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
293 				     const char *protocol,
294 				     const char *netid)
295 {
296 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
297 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
298 	xs_format_common_peer_addresses(xprt);
299 	xs_format_common_peer_ports(xprt);
300 }
301 
302 static void xs_update_peer_port(struct rpc_xprt *xprt)
303 {
304 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
305 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
306 
307 	xs_format_common_peer_ports(xprt);
308 }
309 
310 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
311 {
312 	unsigned int i;
313 
314 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
315 		switch (i) {
316 		case RPC_DISPLAY_PROTO:
317 		case RPC_DISPLAY_NETID:
318 			continue;
319 		default:
320 			kfree(xprt->address_strings[i]);
321 		}
322 }
323 
324 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
325 
326 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
327 {
328 	struct msghdr msg = {
329 		.msg_name	= addr,
330 		.msg_namelen	= addrlen,
331 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
332 	};
333 	struct kvec iov = {
334 		.iov_base	= vec->iov_base + base,
335 		.iov_len	= vec->iov_len - base,
336 	};
337 
338 	if (iov.iov_len != 0)
339 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
340 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
341 }
342 
343 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
344 {
345 	ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
346 			int offset, size_t size, int flags);
347 	struct page **ppage;
348 	unsigned int remainder;
349 	int err;
350 
351 	remainder = xdr->page_len - base;
352 	base += xdr->page_base;
353 	ppage = xdr->pages + (base >> PAGE_SHIFT);
354 	base &= ~PAGE_MASK;
355 	do_sendpage = sock->ops->sendpage;
356 	if (!zerocopy)
357 		do_sendpage = sock_no_sendpage;
358 	for(;;) {
359 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
360 		int flags = XS_SENDMSG_FLAGS;
361 
362 		remainder -= len;
363 		if (remainder != 0 || more)
364 			flags |= MSG_MORE;
365 		err = do_sendpage(sock, *ppage, base, len, flags);
366 		if (remainder == 0 || err != len)
367 			break;
368 		*sent_p += err;
369 		ppage++;
370 		base = 0;
371 	}
372 	if (err > 0) {
373 		*sent_p += err;
374 		err = 0;
375 	}
376 	return err;
377 }
378 
379 /**
380  * xs_sendpages - write pages directly to a socket
381  * @sock: socket to send on
382  * @addr: UDP only -- address of destination
383  * @addrlen: UDP only -- length of destination address
384  * @xdr: buffer containing this request
385  * @base: starting position in the buffer
386  * @zerocopy: true if it is safe to use sendpage()
387  * @sent_p: return the total number of bytes successfully queued for sending
388  *
389  */
390 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
391 {
392 	unsigned int remainder = xdr->len - base;
393 	int err = 0;
394 	int sent = 0;
395 
396 	if (unlikely(!sock))
397 		return -ENOTSOCK;
398 
399 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
400 	if (base != 0) {
401 		addr = NULL;
402 		addrlen = 0;
403 	}
404 
405 	if (base < xdr->head[0].iov_len || addr != NULL) {
406 		unsigned int len = xdr->head[0].iov_len - base;
407 		remainder -= len;
408 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
409 		if (remainder == 0 || err != len)
410 			goto out;
411 		*sent_p += err;
412 		base = 0;
413 	} else
414 		base -= xdr->head[0].iov_len;
415 
416 	if (base < xdr->page_len) {
417 		unsigned int len = xdr->page_len - base;
418 		remainder -= len;
419 		err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
420 		*sent_p += sent;
421 		if (remainder == 0 || sent != len)
422 			goto out;
423 		base = 0;
424 	} else
425 		base -= xdr->page_len;
426 
427 	if (base >= xdr->tail[0].iov_len)
428 		return 0;
429 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
430 out:
431 	if (err > 0) {
432 		*sent_p += err;
433 		err = 0;
434 	}
435 	return err;
436 }
437 
438 static void xs_nospace_callback(struct rpc_task *task)
439 {
440 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
441 
442 	transport->inet->sk_write_pending--;
443 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
444 }
445 
446 /**
447  * xs_nospace - place task on wait queue if transmit was incomplete
448  * @task: task to put to sleep
449  *
450  */
451 static int xs_nospace(struct rpc_task *task)
452 {
453 	struct rpc_rqst *req = task->tk_rqstp;
454 	struct rpc_xprt *xprt = req->rq_xprt;
455 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
456 	struct sock *sk = transport->inet;
457 	int ret = -EAGAIN;
458 
459 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
460 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
461 			req->rq_slen);
462 
463 	/* Protect against races with write_space */
464 	spin_lock_bh(&xprt->transport_lock);
465 
466 	/* Don't race with disconnect */
467 	if (xprt_connected(xprt)) {
468 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
469 			/*
470 			 * Notify TCP that we're limited by the application
471 			 * window size
472 			 */
473 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
474 			sk->sk_write_pending++;
475 			/* ...and wait for more buffer space */
476 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
477 		}
478 	} else {
479 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
480 		ret = -ENOTCONN;
481 	}
482 
483 	spin_unlock_bh(&xprt->transport_lock);
484 
485 	/* Race breaker in case memory is freed before above code is called */
486 	sk->sk_write_space(sk);
487 	return ret;
488 }
489 
490 /*
491  * Construct a stream transport record marker in @buf.
492  */
493 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
494 {
495 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
496 	rpc_fraghdr *base = buf->head[0].iov_base;
497 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
498 }
499 
500 /**
501  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
502  * @task: RPC task that manages the state of an RPC request
503  *
504  * Return values:
505  *        0:	The request has been sent
506  *   EAGAIN:	The socket was blocked, please call again later to
507  *		complete the request
508  * ENOTCONN:	Caller needs to invoke connect logic then call again
509  *    other:	Some other error occured, the request was not sent
510  */
511 static int xs_local_send_request(struct rpc_task *task)
512 {
513 	struct rpc_rqst *req = task->tk_rqstp;
514 	struct rpc_xprt *xprt = req->rq_xprt;
515 	struct sock_xprt *transport =
516 				container_of(xprt, struct sock_xprt, xprt);
517 	struct xdr_buf *xdr = &req->rq_snd_buf;
518 	int status;
519 	int sent = 0;
520 
521 	xs_encode_stream_record_marker(&req->rq_snd_buf);
522 
523 	xs_pktdump("packet data:",
524 			req->rq_svec->iov_base, req->rq_svec->iov_len);
525 
526 	status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
527 			      true, &sent);
528 	dprintk("RPC:       %s(%u) = %d\n",
529 			__func__, xdr->len - req->rq_bytes_sent, status);
530 	if (likely(sent > 0) || status == 0) {
531 		req->rq_bytes_sent += sent;
532 		req->rq_xmit_bytes_sent += sent;
533 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
534 			req->rq_bytes_sent = 0;
535 			return 0;
536 		}
537 		status = -EAGAIN;
538 	}
539 
540 	switch (status) {
541 	case -ENOBUFS:
542 	case -EAGAIN:
543 		status = xs_nospace(task);
544 		break;
545 	default:
546 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
547 			-status);
548 	case -EPIPE:
549 		xs_close(xprt);
550 		status = -ENOTCONN;
551 	}
552 
553 	return status;
554 }
555 
556 /**
557  * xs_udp_send_request - write an RPC request to a UDP socket
558  * @task: address of RPC task that manages the state of an RPC request
559  *
560  * Return values:
561  *        0:	The request has been sent
562  *   EAGAIN:	The socket was blocked, please call again later to
563  *		complete the request
564  * ENOTCONN:	Caller needs to invoke connect logic then call again
565  *    other:	Some other error occurred, the request was not sent
566  */
567 static int xs_udp_send_request(struct rpc_task *task)
568 {
569 	struct rpc_rqst *req = task->tk_rqstp;
570 	struct rpc_xprt *xprt = req->rq_xprt;
571 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
572 	struct xdr_buf *xdr = &req->rq_snd_buf;
573 	int sent = 0;
574 	int status;
575 
576 	xs_pktdump("packet data:",
577 				req->rq_svec->iov_base,
578 				req->rq_svec->iov_len);
579 
580 	if (!xprt_bound(xprt))
581 		return -ENOTCONN;
582 	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
583 			      xdr, req->rq_bytes_sent, true, &sent);
584 
585 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
586 			xdr->len - req->rq_bytes_sent, status);
587 
588 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
589 	if (status == -EPERM)
590 		goto process_status;
591 
592 	if (sent > 0 || status == 0) {
593 		req->rq_xmit_bytes_sent += sent;
594 		if (sent >= req->rq_slen)
595 			return 0;
596 		/* Still some bytes left; set up for a retry later. */
597 		status = -EAGAIN;
598 	}
599 
600 process_status:
601 	switch (status) {
602 	case -ENOTSOCK:
603 		status = -ENOTCONN;
604 		/* Should we call xs_close() here? */
605 		break;
606 	case -EAGAIN:
607 		status = xs_nospace(task);
608 		break;
609 	default:
610 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
611 			-status);
612 	case -ENETUNREACH:
613 	case -ENOBUFS:
614 	case -EPIPE:
615 	case -ECONNREFUSED:
616 	case -EPERM:
617 		/* When the server has died, an ICMP port unreachable message
618 		 * prompts ECONNREFUSED. */
619 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
620 	}
621 
622 	return status;
623 }
624 
625 /**
626  * xs_tcp_shutdown - gracefully shut down a TCP socket
627  * @xprt: transport
628  *
629  * Initiates a graceful shutdown of the TCP socket by calling the
630  * equivalent of shutdown(SHUT_WR);
631  */
632 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
633 {
634 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
635 	struct socket *sock = transport->sock;
636 
637 	if (sock != NULL) {
638 		kernel_sock_shutdown(sock, SHUT_WR);
639 		trace_rpc_socket_shutdown(xprt, sock);
640 	}
641 }
642 
643 /**
644  * xs_tcp_send_request - write an RPC request to a TCP socket
645  * @task: address of RPC task that manages the state of an RPC request
646  *
647  * Return values:
648  *        0:	The request has been sent
649  *   EAGAIN:	The socket was blocked, please call again later to
650  *		complete the request
651  * ENOTCONN:	Caller needs to invoke connect logic then call again
652  *    other:	Some other error occurred, the request was not sent
653  *
654  * XXX: In the case of soft timeouts, should we eventually give up
655  *	if sendmsg is not able to make progress?
656  */
657 static int xs_tcp_send_request(struct rpc_task *task)
658 {
659 	struct rpc_rqst *req = task->tk_rqstp;
660 	struct rpc_xprt *xprt = req->rq_xprt;
661 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
662 	struct xdr_buf *xdr = &req->rq_snd_buf;
663 	bool zerocopy = true;
664 	int status;
665 	int sent;
666 
667 	xs_encode_stream_record_marker(&req->rq_snd_buf);
668 
669 	xs_pktdump("packet data:",
670 				req->rq_svec->iov_base,
671 				req->rq_svec->iov_len);
672 	/* Don't use zero copy if this is a resend. If the RPC call
673 	 * completes while the socket holds a reference to the pages,
674 	 * then we may end up resending corrupted data.
675 	 */
676 	if (task->tk_flags & RPC_TASK_SENT)
677 		zerocopy = false;
678 
679 	/* Continue transmitting the packet/record. We must be careful
680 	 * to cope with writespace callbacks arriving _after_ we have
681 	 * called sendmsg(). */
682 	while (1) {
683 		sent = 0;
684 		status = xs_sendpages(transport->sock, NULL, 0, xdr,
685 				      req->rq_bytes_sent, zerocopy, &sent);
686 
687 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
688 				xdr->len - req->rq_bytes_sent, status);
689 
690 		if (unlikely(sent == 0 && status < 0))
691 			break;
692 
693 		/* If we've sent the entire packet, immediately
694 		 * reset the count of bytes sent. */
695 		req->rq_bytes_sent += sent;
696 		req->rq_xmit_bytes_sent += sent;
697 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
698 			req->rq_bytes_sent = 0;
699 			return 0;
700 		}
701 
702 		if (sent != 0)
703 			continue;
704 		status = -EAGAIN;
705 		break;
706 	}
707 
708 	switch (status) {
709 	case -ENOTSOCK:
710 		status = -ENOTCONN;
711 		/* Should we call xs_close() here? */
712 		break;
713 	case -ENOBUFS:
714 	case -EAGAIN:
715 		status = xs_nospace(task);
716 		break;
717 	default:
718 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
719 			-status);
720 	case -ECONNRESET:
721 		xs_tcp_shutdown(xprt);
722 	case -ECONNREFUSED:
723 	case -ENOTCONN:
724 	case -EPIPE:
725 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
726 	}
727 
728 	return status;
729 }
730 
731 /**
732  * xs_tcp_release_xprt - clean up after a tcp transmission
733  * @xprt: transport
734  * @task: rpc task
735  *
736  * This cleans up if an error causes us to abort the transmission of a request.
737  * In this case, the socket may need to be reset in order to avoid confusing
738  * the server.
739  */
740 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
741 {
742 	struct rpc_rqst *req;
743 
744 	if (task != xprt->snd_task)
745 		return;
746 	if (task == NULL)
747 		goto out_release;
748 	req = task->tk_rqstp;
749 	if (req == NULL)
750 		goto out_release;
751 	if (req->rq_bytes_sent == 0)
752 		goto out_release;
753 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
754 		goto out_release;
755 	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
756 out_release:
757 	xprt_release_xprt(xprt, task);
758 }
759 
760 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
761 {
762 	transport->old_data_ready = sk->sk_data_ready;
763 	transport->old_state_change = sk->sk_state_change;
764 	transport->old_write_space = sk->sk_write_space;
765 	transport->old_error_report = sk->sk_error_report;
766 }
767 
768 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
769 {
770 	sk->sk_data_ready = transport->old_data_ready;
771 	sk->sk_state_change = transport->old_state_change;
772 	sk->sk_write_space = transport->old_write_space;
773 	sk->sk_error_report = transport->old_error_report;
774 }
775 
776 /**
777  * xs_error_report - callback to handle TCP socket state errors
778  * @sk: socket
779  *
780  * Note: we don't call sock_error() since there may be a rpc_task
781  * using the socket, and so we don't want to clear sk->sk_err.
782  */
783 static void xs_error_report(struct sock *sk)
784 {
785 	struct rpc_xprt *xprt;
786 	int err;
787 
788 	read_lock_bh(&sk->sk_callback_lock);
789 	if (!(xprt = xprt_from_sock(sk)))
790 		goto out;
791 
792 	err = -sk->sk_err;
793 	if (err == 0)
794 		goto out;
795 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
796 			xprt, -err);
797 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
798 	if (test_bit(XPRT_CONNECTION_REUSE, &xprt->state))
799 		goto out;
800 	xprt_wake_pending_tasks(xprt, err);
801  out:
802 	read_unlock_bh(&sk->sk_callback_lock);
803 }
804 
805 static void xs_reset_transport(struct sock_xprt *transport)
806 {
807 	struct socket *sock = transport->sock;
808 	struct sock *sk = transport->inet;
809 
810 	if (sk == NULL)
811 		return;
812 
813 	transport->srcport = 0;
814 
815 	write_lock_bh(&sk->sk_callback_lock);
816 	transport->inet = NULL;
817 	transport->sock = NULL;
818 
819 	sk->sk_user_data = NULL;
820 
821 	xs_restore_old_callbacks(transport, sk);
822 	write_unlock_bh(&sk->sk_callback_lock);
823 
824 	trace_rpc_socket_close(&transport->xprt, sock);
825 	sock_release(sock);
826 }
827 
828 /**
829  * xs_close - close a socket
830  * @xprt: transport
831  *
832  * This is used when all requests are complete; ie, no DRC state remains
833  * on the server we want to save.
834  *
835  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
836  * xs_reset_transport() zeroing the socket from underneath a writer.
837  */
838 static void xs_close(struct rpc_xprt *xprt)
839 {
840 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
841 
842 	dprintk("RPC:       xs_close xprt %p\n", xprt);
843 
844 	cancel_delayed_work_sync(&transport->connect_worker);
845 
846 	xs_reset_transport(transport);
847 	xprt->reestablish_timeout = 0;
848 
849 	smp_mb__before_atomic();
850 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
851 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
852 	clear_bit(XPRT_CLOSING, &xprt->state);
853 	smp_mb__after_atomic();
854 	xprt_disconnect_done(xprt);
855 }
856 
857 static void xs_tcp_close(struct rpc_xprt *xprt)
858 {
859 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
860 		xs_close(xprt);
861 	else
862 		xs_tcp_shutdown(xprt);
863 }
864 
865 static void xs_xprt_free(struct rpc_xprt *xprt)
866 {
867 	xs_free_peer_addresses(xprt);
868 	xprt_free(xprt);
869 }
870 
871 /**
872  * xs_destroy - prepare to shutdown a transport
873  * @xprt: doomed transport
874  *
875  */
876 static void xs_destroy(struct rpc_xprt *xprt)
877 {
878 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
879 
880 	xs_close(xprt);
881 	xs_xprt_free(xprt);
882 	module_put(THIS_MODULE);
883 }
884 
885 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
886 {
887 	struct xdr_skb_reader desc = {
888 		.skb		= skb,
889 		.offset		= sizeof(rpc_fraghdr),
890 		.count		= skb->len - sizeof(rpc_fraghdr),
891 	};
892 
893 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
894 		return -1;
895 	if (desc.count)
896 		return -1;
897 	return 0;
898 }
899 
900 /**
901  * xs_local_data_ready - "data ready" callback for AF_LOCAL sockets
902  * @sk: socket with data to read
903  * @len: how much data to read
904  *
905  * Currently this assumes we can read the whole reply in a single gulp.
906  */
907 static void xs_local_data_ready(struct sock *sk)
908 {
909 	struct rpc_task *task;
910 	struct rpc_xprt *xprt;
911 	struct rpc_rqst *rovr;
912 	struct sk_buff *skb;
913 	int err, repsize, copied;
914 	u32 _xid;
915 	__be32 *xp;
916 
917 	read_lock_bh(&sk->sk_callback_lock);
918 	dprintk("RPC:       %s...\n", __func__);
919 	xprt = xprt_from_sock(sk);
920 	if (xprt == NULL)
921 		goto out;
922 
923 	skb = skb_recv_datagram(sk, 0, 1, &err);
924 	if (skb == NULL)
925 		goto out;
926 
927 	repsize = skb->len - sizeof(rpc_fraghdr);
928 	if (repsize < 4) {
929 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
930 		goto dropit;
931 	}
932 
933 	/* Copy the XID from the skb... */
934 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
935 	if (xp == NULL)
936 		goto dropit;
937 
938 	/* Look up and lock the request corresponding to the given XID */
939 	spin_lock(&xprt->transport_lock);
940 	rovr = xprt_lookup_rqst(xprt, *xp);
941 	if (!rovr)
942 		goto out_unlock;
943 	task = rovr->rq_task;
944 
945 	copied = rovr->rq_private_buf.buflen;
946 	if (copied > repsize)
947 		copied = repsize;
948 
949 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
950 		dprintk("RPC:       sk_buff copy failed\n");
951 		goto out_unlock;
952 	}
953 
954 	xprt_complete_rqst(task, copied);
955 
956  out_unlock:
957 	spin_unlock(&xprt->transport_lock);
958  dropit:
959 	skb_free_datagram(sk, skb);
960  out:
961 	read_unlock_bh(&sk->sk_callback_lock);
962 }
963 
964 /**
965  * xs_udp_data_ready - "data ready" callback for UDP sockets
966  * @sk: socket with data to read
967  * @len: how much data to read
968  *
969  */
970 static void xs_udp_data_ready(struct sock *sk)
971 {
972 	struct rpc_task *task;
973 	struct rpc_xprt *xprt;
974 	struct rpc_rqst *rovr;
975 	struct sk_buff *skb;
976 	int err, repsize, copied;
977 	u32 _xid;
978 	__be32 *xp;
979 
980 	read_lock_bh(&sk->sk_callback_lock);
981 	dprintk("RPC:       xs_udp_data_ready...\n");
982 	if (!(xprt = xprt_from_sock(sk)))
983 		goto out;
984 
985 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
986 		goto out;
987 
988 	repsize = skb->len - sizeof(struct udphdr);
989 	if (repsize < 4) {
990 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
991 		goto dropit;
992 	}
993 
994 	/* Copy the XID from the skb... */
995 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
996 				sizeof(_xid), &_xid);
997 	if (xp == NULL)
998 		goto dropit;
999 
1000 	/* Look up and lock the request corresponding to the given XID */
1001 	spin_lock(&xprt->transport_lock);
1002 	rovr = xprt_lookup_rqst(xprt, *xp);
1003 	if (!rovr)
1004 		goto out_unlock;
1005 	task = rovr->rq_task;
1006 
1007 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1008 		copied = repsize;
1009 
1010 	/* Suck it into the iovec, verify checksum if not done by hw. */
1011 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1012 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
1013 		goto out_unlock;
1014 	}
1015 
1016 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
1017 
1018 	xprt_adjust_cwnd(xprt, task, copied);
1019 	xprt_complete_rqst(task, copied);
1020 
1021  out_unlock:
1022 	spin_unlock(&xprt->transport_lock);
1023  dropit:
1024 	skb_free_datagram(sk, skb);
1025  out:
1026 	read_unlock_bh(&sk->sk_callback_lock);
1027 }
1028 
1029 /*
1030  * Helper function to force a TCP close if the server is sending
1031  * junk and/or it has put us in CLOSE_WAIT
1032  */
1033 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1034 {
1035 	set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1036 	xprt_force_disconnect(xprt);
1037 }
1038 
1039 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1040 {
1041 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1042 	size_t len, used;
1043 	char *p;
1044 
1045 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1046 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1047 	used = xdr_skb_read_bits(desc, p, len);
1048 	transport->tcp_offset += used;
1049 	if (used != len)
1050 		return;
1051 
1052 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1053 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1054 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1055 	else
1056 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1057 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1058 
1059 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1060 	transport->tcp_offset = 0;
1061 
1062 	/* Sanity check of the record length */
1063 	if (unlikely(transport->tcp_reclen < 8)) {
1064 		dprintk("RPC:       invalid TCP record fragment length\n");
1065 		xs_tcp_force_close(xprt);
1066 		return;
1067 	}
1068 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1069 			transport->tcp_reclen);
1070 }
1071 
1072 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1073 {
1074 	if (transport->tcp_offset == transport->tcp_reclen) {
1075 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1076 		transport->tcp_offset = 0;
1077 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1078 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1079 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1080 			transport->tcp_copied = 0;
1081 		}
1082 	}
1083 }
1084 
1085 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1086 {
1087 	size_t len, used;
1088 	char *p;
1089 
1090 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1091 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
1092 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1093 	used = xdr_skb_read_bits(desc, p, len);
1094 	transport->tcp_offset += used;
1095 	if (used != len)
1096 		return;
1097 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1098 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1099 	transport->tcp_copied = 4;
1100 	dprintk("RPC:       reading %s XID %08x\n",
1101 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1102 							      : "request with",
1103 			ntohl(transport->tcp_xid));
1104 	xs_tcp_check_fraghdr(transport);
1105 }
1106 
1107 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1108 				       struct xdr_skb_reader *desc)
1109 {
1110 	size_t len, used;
1111 	u32 offset;
1112 	char *p;
1113 
1114 	/*
1115 	 * We want transport->tcp_offset to be 8 at the end of this routine
1116 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1117 	 * When this function is called for the first time,
1118 	 * transport->tcp_offset is 4 (after having already read the xid).
1119 	 */
1120 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1121 	len = sizeof(transport->tcp_calldir) - offset;
1122 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
1123 	p = ((char *) &transport->tcp_calldir) + offset;
1124 	used = xdr_skb_read_bits(desc, p, len);
1125 	transport->tcp_offset += used;
1126 	if (used != len)
1127 		return;
1128 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1129 	/*
1130 	 * We don't yet have the XDR buffer, so we will write the calldir
1131 	 * out after we get the buffer from the 'struct rpc_rqst'
1132 	 */
1133 	switch (ntohl(transport->tcp_calldir)) {
1134 	case RPC_REPLY:
1135 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1136 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1137 		transport->tcp_flags |= TCP_RPC_REPLY;
1138 		break;
1139 	case RPC_CALL:
1140 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1141 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1142 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1143 		break;
1144 	default:
1145 		dprintk("RPC:       invalid request message type\n");
1146 		xs_tcp_force_close(&transport->xprt);
1147 	}
1148 	xs_tcp_check_fraghdr(transport);
1149 }
1150 
1151 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1152 				     struct xdr_skb_reader *desc,
1153 				     struct rpc_rqst *req)
1154 {
1155 	struct sock_xprt *transport =
1156 				container_of(xprt, struct sock_xprt, xprt);
1157 	struct xdr_buf *rcvbuf;
1158 	size_t len;
1159 	ssize_t r;
1160 
1161 	rcvbuf = &req->rq_private_buf;
1162 
1163 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1164 		/*
1165 		 * Save the RPC direction in the XDR buffer
1166 		 */
1167 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1168 			&transport->tcp_calldir,
1169 			sizeof(transport->tcp_calldir));
1170 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1171 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1172 	}
1173 
1174 	len = desc->count;
1175 	if (len > transport->tcp_reclen - transport->tcp_offset) {
1176 		struct xdr_skb_reader my_desc;
1177 
1178 		len = transport->tcp_reclen - transport->tcp_offset;
1179 		memcpy(&my_desc, desc, sizeof(my_desc));
1180 		my_desc.count = len;
1181 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1182 					  &my_desc, xdr_skb_read_bits);
1183 		desc->count -= r;
1184 		desc->offset += r;
1185 	} else
1186 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1187 					  desc, xdr_skb_read_bits);
1188 
1189 	if (r > 0) {
1190 		transport->tcp_copied += r;
1191 		transport->tcp_offset += r;
1192 	}
1193 	if (r != len) {
1194 		/* Error when copying to the receive buffer,
1195 		 * usually because we weren't able to allocate
1196 		 * additional buffer pages. All we can do now
1197 		 * is turn off TCP_RCV_COPY_DATA, so the request
1198 		 * will not receive any additional updates,
1199 		 * and time out.
1200 		 * Any remaining data from this record will
1201 		 * be discarded.
1202 		 */
1203 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1204 		dprintk("RPC:       XID %08x truncated request\n",
1205 				ntohl(transport->tcp_xid));
1206 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1207 				"tcp_offset = %u, tcp_reclen = %u\n",
1208 				xprt, transport->tcp_copied,
1209 				transport->tcp_offset, transport->tcp_reclen);
1210 		return;
1211 	}
1212 
1213 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1214 			ntohl(transport->tcp_xid), r);
1215 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1216 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1217 			transport->tcp_offset, transport->tcp_reclen);
1218 
1219 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1220 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1221 	else if (transport->tcp_offset == transport->tcp_reclen) {
1222 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1223 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1224 	}
1225 }
1226 
1227 /*
1228  * Finds the request corresponding to the RPC xid and invokes the common
1229  * tcp read code to read the data.
1230  */
1231 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1232 				    struct xdr_skb_reader *desc)
1233 {
1234 	struct sock_xprt *transport =
1235 				container_of(xprt, struct sock_xprt, xprt);
1236 	struct rpc_rqst *req;
1237 
1238 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1239 
1240 	/* Find and lock the request corresponding to this xid */
1241 	spin_lock(&xprt->transport_lock);
1242 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1243 	if (!req) {
1244 		dprintk("RPC:       XID %08x request not found!\n",
1245 				ntohl(transport->tcp_xid));
1246 		spin_unlock(&xprt->transport_lock);
1247 		return -1;
1248 	}
1249 
1250 	xs_tcp_read_common(xprt, desc, req);
1251 
1252 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1253 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1254 
1255 	spin_unlock(&xprt->transport_lock);
1256 	return 0;
1257 }
1258 
1259 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1260 /*
1261  * Obtains an rpc_rqst previously allocated and invokes the common
1262  * tcp read code to read the data.  The result is placed in the callback
1263  * queue.
1264  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1265  * connection and return -1.
1266  */
1267 static int xs_tcp_read_callback(struct rpc_xprt *xprt,
1268 				       struct xdr_skb_reader *desc)
1269 {
1270 	struct sock_xprt *transport =
1271 				container_of(xprt, struct sock_xprt, xprt);
1272 	struct rpc_rqst *req;
1273 
1274 	/* Look up and lock the request corresponding to the given XID */
1275 	spin_lock(&xprt->transport_lock);
1276 	req = xprt_lookup_bc_request(xprt, transport->tcp_xid);
1277 	if (req == NULL) {
1278 		spin_unlock(&xprt->transport_lock);
1279 		printk(KERN_WARNING "Callback slot table overflowed\n");
1280 		xprt_force_disconnect(xprt);
1281 		return -1;
1282 	}
1283 
1284 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1285 	xs_tcp_read_common(xprt, desc, req);
1286 
1287 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1288 		xprt_complete_bc_request(req, transport->tcp_copied);
1289 	spin_unlock(&xprt->transport_lock);
1290 
1291 	return 0;
1292 }
1293 
1294 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1295 					struct xdr_skb_reader *desc)
1296 {
1297 	struct sock_xprt *transport =
1298 				container_of(xprt, struct sock_xprt, xprt);
1299 
1300 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1301 		xs_tcp_read_reply(xprt, desc) :
1302 		xs_tcp_read_callback(xprt, desc);
1303 }
1304 #else
1305 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1306 					struct xdr_skb_reader *desc)
1307 {
1308 	return xs_tcp_read_reply(xprt, desc);
1309 }
1310 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1311 
1312 /*
1313  * Read data off the transport.  This can be either an RPC_CALL or an
1314  * RPC_REPLY.  Relay the processing to helper functions.
1315  */
1316 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1317 				    struct xdr_skb_reader *desc)
1318 {
1319 	struct sock_xprt *transport =
1320 				container_of(xprt, struct sock_xprt, xprt);
1321 
1322 	if (_xs_tcp_read_data(xprt, desc) == 0)
1323 		xs_tcp_check_fraghdr(transport);
1324 	else {
1325 		/*
1326 		 * The transport_lock protects the request handling.
1327 		 * There's no need to hold it to update the tcp_flags.
1328 		 */
1329 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1330 	}
1331 }
1332 
1333 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1334 {
1335 	size_t len;
1336 
1337 	len = transport->tcp_reclen - transport->tcp_offset;
1338 	if (len > desc->count)
1339 		len = desc->count;
1340 	desc->count -= len;
1341 	desc->offset += len;
1342 	transport->tcp_offset += len;
1343 	dprintk("RPC:       discarded %Zu bytes\n", len);
1344 	xs_tcp_check_fraghdr(transport);
1345 }
1346 
1347 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1348 {
1349 	struct rpc_xprt *xprt = rd_desc->arg.data;
1350 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1351 	struct xdr_skb_reader desc = {
1352 		.skb	= skb,
1353 		.offset	= offset,
1354 		.count	= len,
1355 	};
1356 
1357 	dprintk("RPC:       xs_tcp_data_recv started\n");
1358 	do {
1359 		trace_xs_tcp_data_recv(transport);
1360 		/* Read in a new fragment marker if necessary */
1361 		/* Can we ever really expect to get completely empty fragments? */
1362 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1363 			xs_tcp_read_fraghdr(xprt, &desc);
1364 			continue;
1365 		}
1366 		/* Read in the xid if necessary */
1367 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1368 			xs_tcp_read_xid(transport, &desc);
1369 			continue;
1370 		}
1371 		/* Read in the call/reply flag */
1372 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1373 			xs_tcp_read_calldir(transport, &desc);
1374 			continue;
1375 		}
1376 		/* Read in the request data */
1377 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1378 			xs_tcp_read_data(xprt, &desc);
1379 			continue;
1380 		}
1381 		/* Skip over any trailing bytes on short reads */
1382 		xs_tcp_read_discard(transport, &desc);
1383 	} while (desc.count);
1384 	trace_xs_tcp_data_recv(transport);
1385 	dprintk("RPC:       xs_tcp_data_recv done\n");
1386 	return len - desc.count;
1387 }
1388 
1389 /**
1390  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1391  * @sk: socket with data to read
1392  * @bytes: how much data to read
1393  *
1394  */
1395 static void xs_tcp_data_ready(struct sock *sk)
1396 {
1397 	struct rpc_xprt *xprt;
1398 	read_descriptor_t rd_desc;
1399 	int read;
1400 	unsigned long total = 0;
1401 
1402 	dprintk("RPC:       xs_tcp_data_ready...\n");
1403 
1404 	read_lock_bh(&sk->sk_callback_lock);
1405 	if (!(xprt = xprt_from_sock(sk))) {
1406 		read = 0;
1407 		goto out;
1408 	}
1409 	/* Any data means we had a useful conversation, so
1410 	 * the we don't need to delay the next reconnect
1411 	 */
1412 	if (xprt->reestablish_timeout)
1413 		xprt->reestablish_timeout = 0;
1414 
1415 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1416 	rd_desc.arg.data = xprt;
1417 	do {
1418 		rd_desc.count = 65536;
1419 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1420 		if (read > 0)
1421 			total += read;
1422 	} while (read > 0);
1423 out:
1424 	trace_xs_tcp_data_ready(xprt, read, total);
1425 	read_unlock_bh(&sk->sk_callback_lock);
1426 }
1427 
1428 /*
1429  * Do the equivalent of linger/linger2 handling for dealing with
1430  * broken servers that don't close the socket in a timely
1431  * fashion
1432  */
1433 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1434 		unsigned long timeout)
1435 {
1436 	struct sock_xprt *transport;
1437 
1438 	if (xprt_test_and_set_connecting(xprt))
1439 		return;
1440 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1441 	transport = container_of(xprt, struct sock_xprt, xprt);
1442 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1443 			   timeout);
1444 }
1445 
1446 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1447 {
1448 	struct sock_xprt *transport;
1449 
1450 	transport = container_of(xprt, struct sock_xprt, xprt);
1451 
1452 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1453 	    !cancel_delayed_work(&transport->connect_worker))
1454 		return;
1455 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1456 	xprt_clear_connecting(xprt);
1457 }
1458 
1459 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1460 {
1461 	smp_mb__before_atomic();
1462 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1463 	clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1464 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1465 	clear_bit(XPRT_CLOSING, &xprt->state);
1466 	smp_mb__after_atomic();
1467 }
1468 
1469 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1470 {
1471 	xs_sock_reset_connection_flags(xprt);
1472 	/* Mark transport as closed and wake up all pending tasks */
1473 	xprt_disconnect_done(xprt);
1474 }
1475 
1476 /**
1477  * xs_tcp_state_change - callback to handle TCP socket state changes
1478  * @sk: socket whose state has changed
1479  *
1480  */
1481 static void xs_tcp_state_change(struct sock *sk)
1482 {
1483 	struct rpc_xprt *xprt;
1484 
1485 	read_lock_bh(&sk->sk_callback_lock);
1486 	if (!(xprt = xprt_from_sock(sk)))
1487 		goto out;
1488 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1489 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1490 			sk->sk_state, xprt_connected(xprt),
1491 			sock_flag(sk, SOCK_DEAD),
1492 			sock_flag(sk, SOCK_ZAPPED),
1493 			sk->sk_shutdown);
1494 
1495 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1496 	switch (sk->sk_state) {
1497 	case TCP_ESTABLISHED:
1498 		spin_lock(&xprt->transport_lock);
1499 		if (!xprt_test_and_set_connected(xprt)) {
1500 			struct sock_xprt *transport = container_of(xprt,
1501 					struct sock_xprt, xprt);
1502 
1503 			/* Reset TCP record info */
1504 			transport->tcp_offset = 0;
1505 			transport->tcp_reclen = 0;
1506 			transport->tcp_copied = 0;
1507 			transport->tcp_flags =
1508 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1509 			xprt->connect_cookie++;
1510 
1511 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1512 		}
1513 		spin_unlock(&xprt->transport_lock);
1514 		break;
1515 	case TCP_FIN_WAIT1:
1516 		/* The client initiated a shutdown of the socket */
1517 		xprt->connect_cookie++;
1518 		xprt->reestablish_timeout = 0;
1519 		set_bit(XPRT_CLOSING, &xprt->state);
1520 		smp_mb__before_atomic();
1521 		clear_bit(XPRT_CONNECTED, &xprt->state);
1522 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1523 		smp_mb__after_atomic();
1524 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1525 		break;
1526 	case TCP_CLOSE_WAIT:
1527 		/* The server initiated a shutdown of the socket */
1528 		xprt->connect_cookie++;
1529 		clear_bit(XPRT_CONNECTED, &xprt->state);
1530 		xs_tcp_force_close(xprt);
1531 	case TCP_CLOSING:
1532 		/*
1533 		 * If the server closed down the connection, make sure that
1534 		 * we back off before reconnecting
1535 		 */
1536 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1537 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1538 		break;
1539 	case TCP_LAST_ACK:
1540 		set_bit(XPRT_CLOSING, &xprt->state);
1541 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1542 		smp_mb__before_atomic();
1543 		clear_bit(XPRT_CONNECTED, &xprt->state);
1544 		smp_mb__after_atomic();
1545 		break;
1546 	case TCP_CLOSE:
1547 		xs_tcp_cancel_linger_timeout(xprt);
1548 		xs_sock_mark_closed(xprt);
1549 	}
1550  out:
1551 	read_unlock_bh(&sk->sk_callback_lock);
1552 }
1553 
1554 static void xs_write_space(struct sock *sk)
1555 {
1556 	struct socket *sock;
1557 	struct rpc_xprt *xprt;
1558 
1559 	if (unlikely(!(sock = sk->sk_socket)))
1560 		return;
1561 	clear_bit(SOCK_NOSPACE, &sock->flags);
1562 
1563 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1564 		return;
1565 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1566 		return;
1567 
1568 	xprt_write_space(xprt);
1569 }
1570 
1571 /**
1572  * xs_udp_write_space - callback invoked when socket buffer space
1573  *                             becomes available
1574  * @sk: socket whose state has changed
1575  *
1576  * Called when more output buffer space is available for this socket.
1577  * We try not to wake our writers until they can make "significant"
1578  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1579  * with a bunch of small requests.
1580  */
1581 static void xs_udp_write_space(struct sock *sk)
1582 {
1583 	read_lock_bh(&sk->sk_callback_lock);
1584 
1585 	/* from net/core/sock.c:sock_def_write_space */
1586 	if (sock_writeable(sk))
1587 		xs_write_space(sk);
1588 
1589 	read_unlock_bh(&sk->sk_callback_lock);
1590 }
1591 
1592 /**
1593  * xs_tcp_write_space - callback invoked when socket buffer space
1594  *                             becomes available
1595  * @sk: socket whose state has changed
1596  *
1597  * Called when more output buffer space is available for this socket.
1598  * We try not to wake our writers until they can make "significant"
1599  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1600  * with a bunch of small requests.
1601  */
1602 static void xs_tcp_write_space(struct sock *sk)
1603 {
1604 	read_lock_bh(&sk->sk_callback_lock);
1605 
1606 	/* from net/core/stream.c:sk_stream_write_space */
1607 	if (sk_stream_is_writeable(sk))
1608 		xs_write_space(sk);
1609 
1610 	read_unlock_bh(&sk->sk_callback_lock);
1611 }
1612 
1613 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1614 {
1615 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1616 	struct sock *sk = transport->inet;
1617 
1618 	if (transport->rcvsize) {
1619 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1620 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1621 	}
1622 	if (transport->sndsize) {
1623 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1624 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1625 		sk->sk_write_space(sk);
1626 	}
1627 }
1628 
1629 /**
1630  * xs_udp_set_buffer_size - set send and receive limits
1631  * @xprt: generic transport
1632  * @sndsize: requested size of send buffer, in bytes
1633  * @rcvsize: requested size of receive buffer, in bytes
1634  *
1635  * Set socket send and receive buffer size limits.
1636  */
1637 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1638 {
1639 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1640 
1641 	transport->sndsize = 0;
1642 	if (sndsize)
1643 		transport->sndsize = sndsize + 1024;
1644 	transport->rcvsize = 0;
1645 	if (rcvsize)
1646 		transport->rcvsize = rcvsize + 1024;
1647 
1648 	xs_udp_do_set_buffer_size(xprt);
1649 }
1650 
1651 /**
1652  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1653  * @task: task that timed out
1654  *
1655  * Adjust the congestion window after a retransmit timeout has occurred.
1656  */
1657 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1658 {
1659 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1660 }
1661 
1662 static unsigned short xs_get_random_port(void)
1663 {
1664 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1665 	unsigned short rand = (unsigned short) prandom_u32() % range;
1666 	return rand + xprt_min_resvport;
1667 }
1668 
1669 /**
1670  * xs_set_port - reset the port number in the remote endpoint address
1671  * @xprt: generic transport
1672  * @port: new port number
1673  *
1674  */
1675 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1676 {
1677 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1678 
1679 	rpc_set_port(xs_addr(xprt), port);
1680 	xs_update_peer_port(xprt);
1681 }
1682 
1683 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1684 {
1685 	unsigned short port = transport->srcport;
1686 
1687 	if (port == 0 && transport->xprt.resvport)
1688 		port = xs_get_random_port();
1689 	return port;
1690 }
1691 
1692 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1693 {
1694 	if (transport->srcport != 0)
1695 		transport->srcport = 0;
1696 	if (!transport->xprt.resvport)
1697 		return 0;
1698 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1699 		return xprt_max_resvport;
1700 	return --port;
1701 }
1702 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1703 {
1704 	struct sockaddr_storage myaddr;
1705 	int err, nloop = 0;
1706 	unsigned short port = xs_get_srcport(transport);
1707 	unsigned short last;
1708 
1709 	/*
1710 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1711 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1712 	 * port selection happen implicitly when the socket is used
1713 	 * (for example at connect time).
1714 	 *
1715 	 * This ensures that we can continue to establish TCP
1716 	 * connections even when all local ephemeral ports are already
1717 	 * a part of some TCP connection.  This makes no difference
1718 	 * for UDP sockets, but also doens't harm them.
1719 	 *
1720 	 * If we're asking for any reserved port (i.e. port == 0 &&
1721 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1722 	 * ensure that port is non-zero and we will bind as needed.
1723 	 */
1724 	if (port == 0)
1725 		return 0;
1726 
1727 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1728 	do {
1729 		rpc_set_port((struct sockaddr *)&myaddr, port);
1730 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1731 				transport->xprt.addrlen);
1732 		if (err == 0) {
1733 			transport->srcport = port;
1734 			break;
1735 		}
1736 		last = port;
1737 		port = xs_next_srcport(transport, port);
1738 		if (port > last)
1739 			nloop++;
1740 	} while (err == -EADDRINUSE && nloop != 2);
1741 
1742 	if (myaddr.ss_family == AF_INET)
1743 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1744 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1745 				port, err ? "failed" : "ok", err);
1746 	else
1747 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1748 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1749 				port, err ? "failed" : "ok", err);
1750 	return err;
1751 }
1752 
1753 /*
1754  * We don't support autobind on AF_LOCAL sockets
1755  */
1756 static void xs_local_rpcbind(struct rpc_task *task)
1757 {
1758 	rcu_read_lock();
1759 	xprt_set_bound(rcu_dereference(task->tk_client->cl_xprt));
1760 	rcu_read_unlock();
1761 }
1762 
1763 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1764 {
1765 }
1766 
1767 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1768 static struct lock_class_key xs_key[2];
1769 static struct lock_class_key xs_slock_key[2];
1770 
1771 static inline void xs_reclassify_socketu(struct socket *sock)
1772 {
1773 	struct sock *sk = sock->sk;
1774 
1775 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1776 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1777 }
1778 
1779 static inline void xs_reclassify_socket4(struct socket *sock)
1780 {
1781 	struct sock *sk = sock->sk;
1782 
1783 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1784 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1785 }
1786 
1787 static inline void xs_reclassify_socket6(struct socket *sock)
1788 {
1789 	struct sock *sk = sock->sk;
1790 
1791 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1792 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1793 }
1794 
1795 static inline void xs_reclassify_socket(int family, struct socket *sock)
1796 {
1797 	WARN_ON_ONCE(sock_owned_by_user(sock->sk));
1798 	if (sock_owned_by_user(sock->sk))
1799 		return;
1800 
1801 	switch (family) {
1802 	case AF_LOCAL:
1803 		xs_reclassify_socketu(sock);
1804 		break;
1805 	case AF_INET:
1806 		xs_reclassify_socket4(sock);
1807 		break;
1808 	case AF_INET6:
1809 		xs_reclassify_socket6(sock);
1810 		break;
1811 	}
1812 }
1813 #else
1814 static inline void xs_reclassify_socketu(struct socket *sock)
1815 {
1816 }
1817 
1818 static inline void xs_reclassify_socket4(struct socket *sock)
1819 {
1820 }
1821 
1822 static inline void xs_reclassify_socket6(struct socket *sock)
1823 {
1824 }
1825 
1826 static inline void xs_reclassify_socket(int family, struct socket *sock)
1827 {
1828 }
1829 #endif
1830 
1831 static void xs_dummy_setup_socket(struct work_struct *work)
1832 {
1833 }
1834 
1835 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1836 		struct sock_xprt *transport, int family, int type, int protocol)
1837 {
1838 	struct socket *sock;
1839 	int err;
1840 
1841 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1842 	if (err < 0) {
1843 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1844 				protocol, -err);
1845 		goto out;
1846 	}
1847 	xs_reclassify_socket(family, sock);
1848 
1849 	err = xs_bind(transport, sock);
1850 	if (err) {
1851 		sock_release(sock);
1852 		goto out;
1853 	}
1854 
1855 	return sock;
1856 out:
1857 	return ERR_PTR(err);
1858 }
1859 
1860 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1861 				      struct socket *sock)
1862 {
1863 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1864 									xprt);
1865 
1866 	if (!transport->inet) {
1867 		struct sock *sk = sock->sk;
1868 
1869 		write_lock_bh(&sk->sk_callback_lock);
1870 
1871 		xs_save_old_callbacks(transport, sk);
1872 
1873 		sk->sk_user_data = xprt;
1874 		sk->sk_data_ready = xs_local_data_ready;
1875 		sk->sk_write_space = xs_udp_write_space;
1876 		sk->sk_error_report = xs_error_report;
1877 		sk->sk_allocation = GFP_ATOMIC;
1878 
1879 		xprt_clear_connected(xprt);
1880 
1881 		/* Reset to new socket */
1882 		transport->sock = sock;
1883 		transport->inet = sk;
1884 
1885 		write_unlock_bh(&sk->sk_callback_lock);
1886 	}
1887 
1888 	/* Tell the socket layer to start connecting... */
1889 	xprt->stat.connect_count++;
1890 	xprt->stat.connect_start = jiffies;
1891 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1892 }
1893 
1894 /**
1895  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1896  * @xprt: RPC transport to connect
1897  * @transport: socket transport to connect
1898  * @create_sock: function to create a socket of the correct type
1899  */
1900 static int xs_local_setup_socket(struct sock_xprt *transport)
1901 {
1902 	struct rpc_xprt *xprt = &transport->xprt;
1903 	struct socket *sock;
1904 	int status = -EIO;
1905 
1906 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1907 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1908 					SOCK_STREAM, 0, &sock, 1);
1909 	if (status < 0) {
1910 		dprintk("RPC:       can't create AF_LOCAL "
1911 			"transport socket (%d).\n", -status);
1912 		goto out;
1913 	}
1914 	xs_reclassify_socketu(sock);
1915 
1916 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1917 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1918 
1919 	status = xs_local_finish_connecting(xprt, sock);
1920 	trace_rpc_socket_connect(xprt, sock, status);
1921 	switch (status) {
1922 	case 0:
1923 		dprintk("RPC:       xprt %p connected to %s\n",
1924 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1925 		xprt_set_connected(xprt);
1926 	case -ENOBUFS:
1927 		break;
1928 	case -ENOENT:
1929 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1930 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1931 		break;
1932 	case -ECONNREFUSED:
1933 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1934 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1935 		break;
1936 	default:
1937 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1938 				__func__, -status,
1939 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1940 	}
1941 
1942 out:
1943 	xprt_clear_connecting(xprt);
1944 	xprt_wake_pending_tasks(xprt, status);
1945 	return status;
1946 }
1947 
1948 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1949 {
1950 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1951 	int ret;
1952 
1953 	 if (RPC_IS_ASYNC(task)) {
1954 		/*
1955 		 * We want the AF_LOCAL connect to be resolved in the
1956 		 * filesystem namespace of the process making the rpc
1957 		 * call.  Thus we connect synchronously.
1958 		 *
1959 		 * If we want to support asynchronous AF_LOCAL calls,
1960 		 * we'll need to figure out how to pass a namespace to
1961 		 * connect.
1962 		 */
1963 		rpc_exit(task, -ENOTCONN);
1964 		return;
1965 	}
1966 	ret = xs_local_setup_socket(transport);
1967 	if (ret && !RPC_IS_SOFTCONN(task))
1968 		msleep_interruptible(15000);
1969 }
1970 
1971 #ifdef CONFIG_SUNRPC_SWAP
1972 static void xs_set_memalloc(struct rpc_xprt *xprt)
1973 {
1974 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1975 			xprt);
1976 
1977 	if (xprt->swapper)
1978 		sk_set_memalloc(transport->inet);
1979 }
1980 
1981 /**
1982  * xs_swapper - Tag this transport as being used for swap.
1983  * @xprt: transport to tag
1984  * @enable: enable/disable
1985  *
1986  */
1987 int xs_swapper(struct rpc_xprt *xprt, int enable)
1988 {
1989 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1990 			xprt);
1991 	int err = 0;
1992 
1993 	if (enable) {
1994 		xprt->swapper++;
1995 		xs_set_memalloc(xprt);
1996 	} else if (xprt->swapper) {
1997 		xprt->swapper--;
1998 		sk_clear_memalloc(transport->inet);
1999 	}
2000 
2001 	return err;
2002 }
2003 EXPORT_SYMBOL_GPL(xs_swapper);
2004 #else
2005 static void xs_set_memalloc(struct rpc_xprt *xprt)
2006 {
2007 }
2008 #endif
2009 
2010 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2011 {
2012 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2013 
2014 	if (!transport->inet) {
2015 		struct sock *sk = sock->sk;
2016 
2017 		write_lock_bh(&sk->sk_callback_lock);
2018 
2019 		xs_save_old_callbacks(transport, sk);
2020 
2021 		sk->sk_user_data = xprt;
2022 		sk->sk_data_ready = xs_udp_data_ready;
2023 		sk->sk_write_space = xs_udp_write_space;
2024 		sk->sk_allocation = GFP_ATOMIC;
2025 
2026 		xprt_set_connected(xprt);
2027 
2028 		/* Reset to new socket */
2029 		transport->sock = sock;
2030 		transport->inet = sk;
2031 
2032 		xs_set_memalloc(xprt);
2033 
2034 		write_unlock_bh(&sk->sk_callback_lock);
2035 	}
2036 	xs_udp_do_set_buffer_size(xprt);
2037 }
2038 
2039 static void xs_udp_setup_socket(struct work_struct *work)
2040 {
2041 	struct sock_xprt *transport =
2042 		container_of(work, struct sock_xprt, connect_worker.work);
2043 	struct rpc_xprt *xprt = &transport->xprt;
2044 	struct socket *sock = transport->sock;
2045 	int status = -EIO;
2046 
2047 	/* Start by resetting any existing state */
2048 	xs_reset_transport(transport);
2049 	sock = xs_create_sock(xprt, transport,
2050 			xs_addr(xprt)->sa_family, SOCK_DGRAM, IPPROTO_UDP);
2051 	if (IS_ERR(sock))
2052 		goto out;
2053 
2054 	dprintk("RPC:       worker connecting xprt %p via %s to "
2055 				"%s (port %s)\n", xprt,
2056 			xprt->address_strings[RPC_DISPLAY_PROTO],
2057 			xprt->address_strings[RPC_DISPLAY_ADDR],
2058 			xprt->address_strings[RPC_DISPLAY_PORT]);
2059 
2060 	xs_udp_finish_connecting(xprt, sock);
2061 	trace_rpc_socket_connect(xprt, sock, 0);
2062 	status = 0;
2063 out:
2064 	xprt_clear_connecting(xprt);
2065 	xprt_wake_pending_tasks(xprt, status);
2066 }
2067 
2068 /*
2069  * We need to preserve the port number so the reply cache on the server can
2070  * find our cached RPC replies when we get around to reconnecting.
2071  */
2072 static void xs_abort_connection(struct sock_xprt *transport)
2073 {
2074 	int result;
2075 	struct sockaddr any;
2076 
2077 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", transport);
2078 
2079 	/*
2080 	 * Disconnect the transport socket by doing a connect operation
2081 	 * with AF_UNSPEC.  This should return immediately...
2082 	 */
2083 	memset(&any, 0, sizeof(any));
2084 	any.sa_family = AF_UNSPEC;
2085 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
2086 	trace_rpc_socket_reset_connection(&transport->xprt,
2087 			transport->sock, result);
2088 	if (!result)
2089 		xs_sock_reset_connection_flags(&transport->xprt);
2090 	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
2091 }
2092 
2093 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
2094 {
2095 	unsigned int state = transport->inet->sk_state;
2096 
2097 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
2098 		/* we don't need to abort the connection if the socket
2099 		 * hasn't undergone a shutdown
2100 		 */
2101 		if (transport->inet->sk_shutdown == 0)
2102 			return;
2103 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
2104 				__func__, transport->inet->sk_shutdown);
2105 	}
2106 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
2107 		/* we don't need to abort the connection if the socket
2108 		 * hasn't undergone a shutdown
2109 		 */
2110 		if (transport->inet->sk_shutdown == 0)
2111 			return;
2112 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
2113 				"sk_shutdown set to %d\n",
2114 				__func__, transport->inet->sk_shutdown);
2115 	}
2116 	xs_abort_connection(transport);
2117 }
2118 
2119 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2120 {
2121 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2122 	int ret = -ENOTCONN;
2123 
2124 	if (!transport->inet) {
2125 		struct sock *sk = sock->sk;
2126 		unsigned int keepidle = xprt->timeout->to_initval / HZ;
2127 		unsigned int keepcnt = xprt->timeout->to_retries + 1;
2128 		unsigned int opt_on = 1;
2129 
2130 		/* TCP Keepalive options */
2131 		kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
2132 				(char *)&opt_on, sizeof(opt_on));
2133 		kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
2134 				(char *)&keepidle, sizeof(keepidle));
2135 		kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
2136 				(char *)&keepidle, sizeof(keepidle));
2137 		kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
2138 				(char *)&keepcnt, sizeof(keepcnt));
2139 
2140 		write_lock_bh(&sk->sk_callback_lock);
2141 
2142 		xs_save_old_callbacks(transport, sk);
2143 
2144 		sk->sk_user_data = xprt;
2145 		sk->sk_data_ready = xs_tcp_data_ready;
2146 		sk->sk_state_change = xs_tcp_state_change;
2147 		sk->sk_write_space = xs_tcp_write_space;
2148 		sk->sk_error_report = xs_error_report;
2149 		sk->sk_allocation = GFP_ATOMIC;
2150 
2151 		/* socket options */
2152 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
2153 		sock_reset_flag(sk, SOCK_LINGER);
2154 		tcp_sk(sk)->linger2 = 0;
2155 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2156 
2157 		xprt_clear_connected(xprt);
2158 
2159 		/* Reset to new socket */
2160 		transport->sock = sock;
2161 		transport->inet = sk;
2162 
2163 		write_unlock_bh(&sk->sk_callback_lock);
2164 	}
2165 
2166 	if (!xprt_bound(xprt))
2167 		goto out;
2168 
2169 	xs_set_memalloc(xprt);
2170 
2171 	/* Tell the socket layer to start connecting... */
2172 	xprt->stat.connect_count++;
2173 	xprt->stat.connect_start = jiffies;
2174 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2175 	switch (ret) {
2176 	case 0:
2177 	case -EINPROGRESS:
2178 		/* SYN_SENT! */
2179 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2180 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2181 	}
2182 out:
2183 	return ret;
2184 }
2185 
2186 /**
2187  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2188  * @xprt: RPC transport to connect
2189  * @transport: socket transport to connect
2190  * @create_sock: function to create a socket of the correct type
2191  *
2192  * Invoked by a work queue tasklet.
2193  */
2194 static void xs_tcp_setup_socket(struct work_struct *work)
2195 {
2196 	struct sock_xprt *transport =
2197 		container_of(work, struct sock_xprt, connect_worker.work);
2198 	struct socket *sock = transport->sock;
2199 	struct rpc_xprt *xprt = &transport->xprt;
2200 	int status = -EIO;
2201 
2202 	if (!sock) {
2203 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
2204 		sock = xs_create_sock(xprt, transport,
2205 				xs_addr(xprt)->sa_family, SOCK_STREAM, IPPROTO_TCP);
2206 		if (IS_ERR(sock)) {
2207 			status = PTR_ERR(sock);
2208 			goto out;
2209 		}
2210 	} else {
2211 		int abort_and_exit;
2212 
2213 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
2214 				&xprt->state);
2215 		/* "close" the socket, preserving the local port */
2216 		set_bit(XPRT_CONNECTION_REUSE, &xprt->state);
2217 		xs_tcp_reuse_connection(transport);
2218 		clear_bit(XPRT_CONNECTION_REUSE, &xprt->state);
2219 
2220 		if (abort_and_exit)
2221 			goto out_eagain;
2222 	}
2223 
2224 	dprintk("RPC:       worker connecting xprt %p via %s to "
2225 				"%s (port %s)\n", xprt,
2226 			xprt->address_strings[RPC_DISPLAY_PROTO],
2227 			xprt->address_strings[RPC_DISPLAY_ADDR],
2228 			xprt->address_strings[RPC_DISPLAY_PORT]);
2229 
2230 	status = xs_tcp_finish_connecting(xprt, sock);
2231 	trace_rpc_socket_connect(xprt, sock, status);
2232 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2233 			xprt, -status, xprt_connected(xprt),
2234 			sock->sk->sk_state);
2235 	switch (status) {
2236 	default:
2237 		printk("%s: connect returned unhandled error %d\n",
2238 			__func__, status);
2239 	case -EADDRNOTAVAIL:
2240 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2241 		 * and retry
2242 		 */
2243 		xs_tcp_force_close(xprt);
2244 		break;
2245 	case 0:
2246 	case -EINPROGRESS:
2247 	case -EALREADY:
2248 		xprt_clear_connecting(xprt);
2249 		return;
2250 	case -EINVAL:
2251 		/* Happens, for instance, if the user specified a link
2252 		 * local IPv6 address without a scope-id.
2253 		 */
2254 	case -ECONNREFUSED:
2255 	case -ECONNRESET:
2256 	case -ENETUNREACH:
2257 	case -ENOBUFS:
2258 		/* retry with existing socket, after a delay */
2259 		goto out;
2260 	}
2261 out_eagain:
2262 	status = -EAGAIN;
2263 out:
2264 	xprt_clear_connecting(xprt);
2265 	xprt_wake_pending_tasks(xprt, status);
2266 }
2267 
2268 /**
2269  * xs_connect - connect a socket to a remote endpoint
2270  * @xprt: pointer to transport structure
2271  * @task: address of RPC task that manages state of connect request
2272  *
2273  * TCP: If the remote end dropped the connection, delay reconnecting.
2274  *
2275  * UDP socket connects are synchronous, but we use a work queue anyway
2276  * to guarantee that even unprivileged user processes can set up a
2277  * socket on a privileged port.
2278  *
2279  * If a UDP socket connect fails, the delay behavior here prevents
2280  * retry floods (hard mounts).
2281  */
2282 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2283 {
2284 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2285 
2286 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2287 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2288 				"seconds\n",
2289 				xprt, xprt->reestablish_timeout / HZ);
2290 		queue_delayed_work(rpciod_workqueue,
2291 				   &transport->connect_worker,
2292 				   xprt->reestablish_timeout);
2293 		xprt->reestablish_timeout <<= 1;
2294 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2295 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2296 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2297 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2298 	} else {
2299 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2300 		queue_delayed_work(rpciod_workqueue,
2301 				   &transport->connect_worker, 0);
2302 	}
2303 }
2304 
2305 /**
2306  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2307  * @xprt: rpc_xprt struct containing statistics
2308  * @seq: output file
2309  *
2310  */
2311 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2312 {
2313 	long idle_time = 0;
2314 
2315 	if (xprt_connected(xprt))
2316 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2317 
2318 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2319 			"%llu %llu %lu %llu %llu\n",
2320 			xprt->stat.bind_count,
2321 			xprt->stat.connect_count,
2322 			xprt->stat.connect_time,
2323 			idle_time,
2324 			xprt->stat.sends,
2325 			xprt->stat.recvs,
2326 			xprt->stat.bad_xids,
2327 			xprt->stat.req_u,
2328 			xprt->stat.bklog_u,
2329 			xprt->stat.max_slots,
2330 			xprt->stat.sending_u,
2331 			xprt->stat.pending_u);
2332 }
2333 
2334 /**
2335  * xs_udp_print_stats - display UDP socket-specifc stats
2336  * @xprt: rpc_xprt struct containing statistics
2337  * @seq: output file
2338  *
2339  */
2340 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2341 {
2342 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2343 
2344 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2345 			"%lu %llu %llu\n",
2346 			transport->srcport,
2347 			xprt->stat.bind_count,
2348 			xprt->stat.sends,
2349 			xprt->stat.recvs,
2350 			xprt->stat.bad_xids,
2351 			xprt->stat.req_u,
2352 			xprt->stat.bklog_u,
2353 			xprt->stat.max_slots,
2354 			xprt->stat.sending_u,
2355 			xprt->stat.pending_u);
2356 }
2357 
2358 /**
2359  * xs_tcp_print_stats - display TCP socket-specifc stats
2360  * @xprt: rpc_xprt struct containing statistics
2361  * @seq: output file
2362  *
2363  */
2364 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2365 {
2366 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2367 	long idle_time = 0;
2368 
2369 	if (xprt_connected(xprt))
2370 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2371 
2372 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2373 			"%llu %llu %lu %llu %llu\n",
2374 			transport->srcport,
2375 			xprt->stat.bind_count,
2376 			xprt->stat.connect_count,
2377 			xprt->stat.connect_time,
2378 			idle_time,
2379 			xprt->stat.sends,
2380 			xprt->stat.recvs,
2381 			xprt->stat.bad_xids,
2382 			xprt->stat.req_u,
2383 			xprt->stat.bklog_u,
2384 			xprt->stat.max_slots,
2385 			xprt->stat.sending_u,
2386 			xprt->stat.pending_u);
2387 }
2388 
2389 /*
2390  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2391  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2392  * to use the server side send routines.
2393  */
2394 static void *bc_malloc(struct rpc_task *task, size_t size)
2395 {
2396 	struct page *page;
2397 	struct rpc_buffer *buf;
2398 
2399 	WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2400 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
2401 		return NULL;
2402 
2403 	page = alloc_page(GFP_KERNEL);
2404 	if (!page)
2405 		return NULL;
2406 
2407 	buf = page_address(page);
2408 	buf->len = PAGE_SIZE;
2409 
2410 	return buf->data;
2411 }
2412 
2413 /*
2414  * Free the space allocated in the bc_alloc routine
2415  */
2416 static void bc_free(void *buffer)
2417 {
2418 	struct rpc_buffer *buf;
2419 
2420 	if (!buffer)
2421 		return;
2422 
2423 	buf = container_of(buffer, struct rpc_buffer, data);
2424 	free_page((unsigned long)buf);
2425 }
2426 
2427 /*
2428  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2429  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2430  */
2431 static int bc_sendto(struct rpc_rqst *req)
2432 {
2433 	int len;
2434 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2435 	struct rpc_xprt *xprt = req->rq_xprt;
2436 	struct sock_xprt *transport =
2437 				container_of(xprt, struct sock_xprt, xprt);
2438 	struct socket *sock = transport->sock;
2439 	unsigned long headoff;
2440 	unsigned long tailoff;
2441 
2442 	xs_encode_stream_record_marker(xbufp);
2443 
2444 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2445 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2446 	len = svc_send_common(sock, xbufp,
2447 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2448 			      xbufp->tail[0].iov_base, tailoff);
2449 
2450 	if (len != xbufp->len) {
2451 		printk(KERN_NOTICE "Error sending entire callback!\n");
2452 		len = -EAGAIN;
2453 	}
2454 
2455 	return len;
2456 }
2457 
2458 /*
2459  * The send routine. Borrows from svc_send
2460  */
2461 static int bc_send_request(struct rpc_task *task)
2462 {
2463 	struct rpc_rqst *req = task->tk_rqstp;
2464 	struct svc_xprt	*xprt;
2465 	u32                     len;
2466 
2467 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2468 	/*
2469 	 * Get the server socket associated with this callback xprt
2470 	 */
2471 	xprt = req->rq_xprt->bc_xprt;
2472 
2473 	/*
2474 	 * Grab the mutex to serialize data as the connection is shared
2475 	 * with the fore channel
2476 	 */
2477 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2478 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2479 		if (!mutex_trylock(&xprt->xpt_mutex))
2480 			return -EAGAIN;
2481 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2482 	}
2483 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2484 		len = -ENOTCONN;
2485 	else
2486 		len = bc_sendto(req);
2487 	mutex_unlock(&xprt->xpt_mutex);
2488 
2489 	if (len > 0)
2490 		len = 0;
2491 
2492 	return len;
2493 }
2494 
2495 /*
2496  * The close routine. Since this is client initiated, we do nothing
2497  */
2498 
2499 static void bc_close(struct rpc_xprt *xprt)
2500 {
2501 }
2502 
2503 /*
2504  * The xprt destroy routine. Again, because this connection is client
2505  * initiated, we do nothing
2506  */
2507 
2508 static void bc_destroy(struct rpc_xprt *xprt)
2509 {
2510 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2511 
2512 	xs_xprt_free(xprt);
2513 	module_put(THIS_MODULE);
2514 }
2515 
2516 static struct rpc_xprt_ops xs_local_ops = {
2517 	.reserve_xprt		= xprt_reserve_xprt,
2518 	.release_xprt		= xs_tcp_release_xprt,
2519 	.alloc_slot		= xprt_alloc_slot,
2520 	.rpcbind		= xs_local_rpcbind,
2521 	.set_port		= xs_local_set_port,
2522 	.connect		= xs_local_connect,
2523 	.buf_alloc		= rpc_malloc,
2524 	.buf_free		= rpc_free,
2525 	.send_request		= xs_local_send_request,
2526 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2527 	.close			= xs_close,
2528 	.destroy		= xs_destroy,
2529 	.print_stats		= xs_local_print_stats,
2530 };
2531 
2532 static struct rpc_xprt_ops xs_udp_ops = {
2533 	.set_buffer_size	= xs_udp_set_buffer_size,
2534 	.reserve_xprt		= xprt_reserve_xprt_cong,
2535 	.release_xprt		= xprt_release_xprt_cong,
2536 	.alloc_slot		= xprt_alloc_slot,
2537 	.rpcbind		= rpcb_getport_async,
2538 	.set_port		= xs_set_port,
2539 	.connect		= xs_connect,
2540 	.buf_alloc		= rpc_malloc,
2541 	.buf_free		= rpc_free,
2542 	.send_request		= xs_udp_send_request,
2543 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2544 	.timer			= xs_udp_timer,
2545 	.release_request	= xprt_release_rqst_cong,
2546 	.close			= xs_close,
2547 	.destroy		= xs_destroy,
2548 	.print_stats		= xs_udp_print_stats,
2549 };
2550 
2551 static struct rpc_xprt_ops xs_tcp_ops = {
2552 	.reserve_xprt		= xprt_reserve_xprt,
2553 	.release_xprt		= xs_tcp_release_xprt,
2554 	.alloc_slot		= xprt_lock_and_alloc_slot,
2555 	.rpcbind		= rpcb_getport_async,
2556 	.set_port		= xs_set_port,
2557 	.connect		= xs_connect,
2558 	.buf_alloc		= rpc_malloc,
2559 	.buf_free		= rpc_free,
2560 	.send_request		= xs_tcp_send_request,
2561 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2562 	.close			= xs_tcp_close,
2563 	.destroy		= xs_destroy,
2564 	.print_stats		= xs_tcp_print_stats,
2565 };
2566 
2567 /*
2568  * The rpc_xprt_ops for the server backchannel
2569  */
2570 
2571 static struct rpc_xprt_ops bc_tcp_ops = {
2572 	.reserve_xprt		= xprt_reserve_xprt,
2573 	.release_xprt		= xprt_release_xprt,
2574 	.alloc_slot		= xprt_alloc_slot,
2575 	.buf_alloc		= bc_malloc,
2576 	.buf_free		= bc_free,
2577 	.send_request		= bc_send_request,
2578 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2579 	.close			= bc_close,
2580 	.destroy		= bc_destroy,
2581 	.print_stats		= xs_tcp_print_stats,
2582 };
2583 
2584 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2585 {
2586 	static const struct sockaddr_in sin = {
2587 		.sin_family		= AF_INET,
2588 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2589 	};
2590 	static const struct sockaddr_in6 sin6 = {
2591 		.sin6_family		= AF_INET6,
2592 		.sin6_addr		= IN6ADDR_ANY_INIT,
2593 	};
2594 
2595 	switch (family) {
2596 	case AF_LOCAL:
2597 		break;
2598 	case AF_INET:
2599 		memcpy(sap, &sin, sizeof(sin));
2600 		break;
2601 	case AF_INET6:
2602 		memcpy(sap, &sin6, sizeof(sin6));
2603 		break;
2604 	default:
2605 		dprintk("RPC:       %s: Bad address family\n", __func__);
2606 		return -EAFNOSUPPORT;
2607 	}
2608 	return 0;
2609 }
2610 
2611 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2612 				      unsigned int slot_table_size,
2613 				      unsigned int max_slot_table_size)
2614 {
2615 	struct rpc_xprt *xprt;
2616 	struct sock_xprt *new;
2617 
2618 	if (args->addrlen > sizeof(xprt->addr)) {
2619 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2620 		return ERR_PTR(-EBADF);
2621 	}
2622 
2623 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2624 			max_slot_table_size);
2625 	if (xprt == NULL) {
2626 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2627 				"rpc_xprt\n");
2628 		return ERR_PTR(-ENOMEM);
2629 	}
2630 
2631 	new = container_of(xprt, struct sock_xprt, xprt);
2632 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2633 	xprt->addrlen = args->addrlen;
2634 	if (args->srcaddr)
2635 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2636 	else {
2637 		int err;
2638 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2639 					(struct sockaddr *)&new->srcaddr);
2640 		if (err != 0) {
2641 			xprt_free(xprt);
2642 			return ERR_PTR(err);
2643 		}
2644 	}
2645 
2646 	return xprt;
2647 }
2648 
2649 static const struct rpc_timeout xs_local_default_timeout = {
2650 	.to_initval = 10 * HZ,
2651 	.to_maxval = 10 * HZ,
2652 	.to_retries = 2,
2653 };
2654 
2655 /**
2656  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2657  * @args: rpc transport creation arguments
2658  *
2659  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2660  */
2661 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2662 {
2663 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2664 	struct sock_xprt *transport;
2665 	struct rpc_xprt *xprt;
2666 	struct rpc_xprt *ret;
2667 
2668 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2669 			xprt_max_tcp_slot_table_entries);
2670 	if (IS_ERR(xprt))
2671 		return xprt;
2672 	transport = container_of(xprt, struct sock_xprt, xprt);
2673 
2674 	xprt->prot = 0;
2675 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2676 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2677 
2678 	xprt->bind_timeout = XS_BIND_TO;
2679 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2680 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2681 
2682 	xprt->ops = &xs_local_ops;
2683 	xprt->timeout = &xs_local_default_timeout;
2684 
2685 	INIT_DELAYED_WORK(&transport->connect_worker,
2686 			xs_dummy_setup_socket);
2687 
2688 	switch (sun->sun_family) {
2689 	case AF_LOCAL:
2690 		if (sun->sun_path[0] != '/') {
2691 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2692 					sun->sun_path);
2693 			ret = ERR_PTR(-EINVAL);
2694 			goto out_err;
2695 		}
2696 		xprt_set_bound(xprt);
2697 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2698 		ret = ERR_PTR(xs_local_setup_socket(transport));
2699 		if (ret)
2700 			goto out_err;
2701 		break;
2702 	default:
2703 		ret = ERR_PTR(-EAFNOSUPPORT);
2704 		goto out_err;
2705 	}
2706 
2707 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2708 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2709 
2710 	if (try_module_get(THIS_MODULE))
2711 		return xprt;
2712 	ret = ERR_PTR(-EINVAL);
2713 out_err:
2714 	xs_xprt_free(xprt);
2715 	return ret;
2716 }
2717 
2718 static const struct rpc_timeout xs_udp_default_timeout = {
2719 	.to_initval = 5 * HZ,
2720 	.to_maxval = 30 * HZ,
2721 	.to_increment = 5 * HZ,
2722 	.to_retries = 5,
2723 };
2724 
2725 /**
2726  * xs_setup_udp - Set up transport to use a UDP socket
2727  * @args: rpc transport creation arguments
2728  *
2729  */
2730 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2731 {
2732 	struct sockaddr *addr = args->dstaddr;
2733 	struct rpc_xprt *xprt;
2734 	struct sock_xprt *transport;
2735 	struct rpc_xprt *ret;
2736 
2737 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2738 			xprt_udp_slot_table_entries);
2739 	if (IS_ERR(xprt))
2740 		return xprt;
2741 	transport = container_of(xprt, struct sock_xprt, xprt);
2742 
2743 	xprt->prot = IPPROTO_UDP;
2744 	xprt->tsh_size = 0;
2745 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2746 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2747 
2748 	xprt->bind_timeout = XS_BIND_TO;
2749 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2750 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2751 
2752 	xprt->ops = &xs_udp_ops;
2753 
2754 	xprt->timeout = &xs_udp_default_timeout;
2755 
2756 	switch (addr->sa_family) {
2757 	case AF_INET:
2758 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2759 			xprt_set_bound(xprt);
2760 
2761 		INIT_DELAYED_WORK(&transport->connect_worker,
2762 					xs_udp_setup_socket);
2763 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2764 		break;
2765 	case AF_INET6:
2766 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2767 			xprt_set_bound(xprt);
2768 
2769 		INIT_DELAYED_WORK(&transport->connect_worker,
2770 					xs_udp_setup_socket);
2771 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2772 		break;
2773 	default:
2774 		ret = ERR_PTR(-EAFNOSUPPORT);
2775 		goto out_err;
2776 	}
2777 
2778 	if (xprt_bound(xprt))
2779 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2780 				xprt->address_strings[RPC_DISPLAY_ADDR],
2781 				xprt->address_strings[RPC_DISPLAY_PORT],
2782 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2783 	else
2784 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2785 				xprt->address_strings[RPC_DISPLAY_ADDR],
2786 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2787 
2788 	if (try_module_get(THIS_MODULE))
2789 		return xprt;
2790 	ret = ERR_PTR(-EINVAL);
2791 out_err:
2792 	xs_xprt_free(xprt);
2793 	return ret;
2794 }
2795 
2796 static const struct rpc_timeout xs_tcp_default_timeout = {
2797 	.to_initval = 60 * HZ,
2798 	.to_maxval = 60 * HZ,
2799 	.to_retries = 2,
2800 };
2801 
2802 /**
2803  * xs_setup_tcp - Set up transport to use a TCP socket
2804  * @args: rpc transport creation arguments
2805  *
2806  */
2807 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2808 {
2809 	struct sockaddr *addr = args->dstaddr;
2810 	struct rpc_xprt *xprt;
2811 	struct sock_xprt *transport;
2812 	struct rpc_xprt *ret;
2813 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
2814 
2815 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
2816 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
2817 
2818 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2819 			max_slot_table_size);
2820 	if (IS_ERR(xprt))
2821 		return xprt;
2822 	transport = container_of(xprt, struct sock_xprt, xprt);
2823 
2824 	xprt->prot = IPPROTO_TCP;
2825 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2826 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2827 
2828 	xprt->bind_timeout = XS_BIND_TO;
2829 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2830 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2831 
2832 	xprt->ops = &xs_tcp_ops;
2833 	xprt->timeout = &xs_tcp_default_timeout;
2834 
2835 	switch (addr->sa_family) {
2836 	case AF_INET:
2837 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2838 			xprt_set_bound(xprt);
2839 
2840 		INIT_DELAYED_WORK(&transport->connect_worker,
2841 					xs_tcp_setup_socket);
2842 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2843 		break;
2844 	case AF_INET6:
2845 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2846 			xprt_set_bound(xprt);
2847 
2848 		INIT_DELAYED_WORK(&transport->connect_worker,
2849 					xs_tcp_setup_socket);
2850 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2851 		break;
2852 	default:
2853 		ret = ERR_PTR(-EAFNOSUPPORT);
2854 		goto out_err;
2855 	}
2856 
2857 	if (xprt_bound(xprt))
2858 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2859 				xprt->address_strings[RPC_DISPLAY_ADDR],
2860 				xprt->address_strings[RPC_DISPLAY_PORT],
2861 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2862 	else
2863 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2864 				xprt->address_strings[RPC_DISPLAY_ADDR],
2865 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2866 
2867 	if (try_module_get(THIS_MODULE))
2868 		return xprt;
2869 	ret = ERR_PTR(-EINVAL);
2870 out_err:
2871 	xs_xprt_free(xprt);
2872 	return ret;
2873 }
2874 
2875 /**
2876  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2877  * @args: rpc transport creation arguments
2878  *
2879  */
2880 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2881 {
2882 	struct sockaddr *addr = args->dstaddr;
2883 	struct rpc_xprt *xprt;
2884 	struct sock_xprt *transport;
2885 	struct svc_sock *bc_sock;
2886 	struct rpc_xprt *ret;
2887 
2888 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2889 			xprt_tcp_slot_table_entries);
2890 	if (IS_ERR(xprt))
2891 		return xprt;
2892 	transport = container_of(xprt, struct sock_xprt, xprt);
2893 
2894 	xprt->prot = IPPROTO_TCP;
2895 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2896 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2897 	xprt->timeout = &xs_tcp_default_timeout;
2898 
2899 	/* backchannel */
2900 	xprt_set_bound(xprt);
2901 	xprt->bind_timeout = 0;
2902 	xprt->reestablish_timeout = 0;
2903 	xprt->idle_timeout = 0;
2904 
2905 	xprt->ops = &bc_tcp_ops;
2906 
2907 	switch (addr->sa_family) {
2908 	case AF_INET:
2909 		xs_format_peer_addresses(xprt, "tcp",
2910 					 RPCBIND_NETID_TCP);
2911 		break;
2912 	case AF_INET6:
2913 		xs_format_peer_addresses(xprt, "tcp",
2914 				   RPCBIND_NETID_TCP6);
2915 		break;
2916 	default:
2917 		ret = ERR_PTR(-EAFNOSUPPORT);
2918 		goto out_err;
2919 	}
2920 
2921 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2922 			xprt->address_strings[RPC_DISPLAY_ADDR],
2923 			xprt->address_strings[RPC_DISPLAY_PORT],
2924 			xprt->address_strings[RPC_DISPLAY_PROTO]);
2925 
2926 	/*
2927 	 * Once we've associated a backchannel xprt with a connection,
2928 	 * we want to keep it around as long as the connection lasts,
2929 	 * in case we need to start using it for a backchannel again;
2930 	 * this reference won't be dropped until bc_xprt is destroyed.
2931 	 */
2932 	xprt_get(xprt);
2933 	args->bc_xprt->xpt_bc_xprt = xprt;
2934 	xprt->bc_xprt = args->bc_xprt;
2935 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2936 	transport->sock = bc_sock->sk_sock;
2937 	transport->inet = bc_sock->sk_sk;
2938 
2939 	/*
2940 	 * Since we don't want connections for the backchannel, we set
2941 	 * the xprt status to connected
2942 	 */
2943 	xprt_set_connected(xprt);
2944 
2945 	if (try_module_get(THIS_MODULE))
2946 		return xprt;
2947 
2948 	args->bc_xprt->xpt_bc_xprt = NULL;
2949 	xprt_put(xprt);
2950 	ret = ERR_PTR(-EINVAL);
2951 out_err:
2952 	xs_xprt_free(xprt);
2953 	return ret;
2954 }
2955 
2956 static struct xprt_class	xs_local_transport = {
2957 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
2958 	.name		= "named UNIX socket",
2959 	.owner		= THIS_MODULE,
2960 	.ident		= XPRT_TRANSPORT_LOCAL,
2961 	.setup		= xs_setup_local,
2962 };
2963 
2964 static struct xprt_class	xs_udp_transport = {
2965 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2966 	.name		= "udp",
2967 	.owner		= THIS_MODULE,
2968 	.ident		= XPRT_TRANSPORT_UDP,
2969 	.setup		= xs_setup_udp,
2970 };
2971 
2972 static struct xprt_class	xs_tcp_transport = {
2973 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2974 	.name		= "tcp",
2975 	.owner		= THIS_MODULE,
2976 	.ident		= XPRT_TRANSPORT_TCP,
2977 	.setup		= xs_setup_tcp,
2978 };
2979 
2980 static struct xprt_class	xs_bc_tcp_transport = {
2981 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2982 	.name		= "tcp NFSv4.1 backchannel",
2983 	.owner		= THIS_MODULE,
2984 	.ident		= XPRT_TRANSPORT_BC_TCP,
2985 	.setup		= xs_setup_bc_tcp,
2986 };
2987 
2988 /**
2989  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2990  *
2991  */
2992 int init_socket_xprt(void)
2993 {
2994 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2995 	if (!sunrpc_table_header)
2996 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2997 #endif
2998 
2999 	xprt_register_transport(&xs_local_transport);
3000 	xprt_register_transport(&xs_udp_transport);
3001 	xprt_register_transport(&xs_tcp_transport);
3002 	xprt_register_transport(&xs_bc_tcp_transport);
3003 
3004 	return 0;
3005 }
3006 
3007 /**
3008  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3009  *
3010  */
3011 void cleanup_socket_xprt(void)
3012 {
3013 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3014 	if (sunrpc_table_header) {
3015 		unregister_sysctl_table(sunrpc_table_header);
3016 		sunrpc_table_header = NULL;
3017 	}
3018 #endif
3019 
3020 	xprt_unregister_transport(&xs_local_transport);
3021 	xprt_unregister_transport(&xs_udp_transport);
3022 	xprt_unregister_transport(&xs_tcp_transport);
3023 	xprt_unregister_transport(&xs_bc_tcp_transport);
3024 }
3025 
3026 static int param_set_uint_minmax(const char *val,
3027 		const struct kernel_param *kp,
3028 		unsigned int min, unsigned int max)
3029 {
3030 	unsigned int num;
3031 	int ret;
3032 
3033 	if (!val)
3034 		return -EINVAL;
3035 	ret = kstrtouint(val, 0, &num);
3036 	if (ret == -EINVAL || num < min || num > max)
3037 		return -EINVAL;
3038 	*((unsigned int *)kp->arg) = num;
3039 	return 0;
3040 }
3041 
3042 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3043 {
3044 	return param_set_uint_minmax(val, kp,
3045 			RPC_MIN_RESVPORT,
3046 			RPC_MAX_RESVPORT);
3047 }
3048 
3049 static struct kernel_param_ops param_ops_portnr = {
3050 	.set = param_set_portnr,
3051 	.get = param_get_uint,
3052 };
3053 
3054 #define param_check_portnr(name, p) \
3055 	__param_check(name, p, unsigned int);
3056 
3057 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3058 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3059 
3060 static int param_set_slot_table_size(const char *val,
3061 				     const struct kernel_param *kp)
3062 {
3063 	return param_set_uint_minmax(val, kp,
3064 			RPC_MIN_SLOT_TABLE,
3065 			RPC_MAX_SLOT_TABLE);
3066 }
3067 
3068 static struct kernel_param_ops param_ops_slot_table_size = {
3069 	.set = param_set_slot_table_size,
3070 	.get = param_get_uint,
3071 };
3072 
3073 #define param_check_slot_table_size(name, p) \
3074 	__param_check(name, p, unsigned int);
3075 
3076 static int param_set_max_slot_table_size(const char *val,
3077 				     const struct kernel_param *kp)
3078 {
3079 	return param_set_uint_minmax(val, kp,
3080 			RPC_MIN_SLOT_TABLE,
3081 			RPC_MAX_SLOT_TABLE_LIMIT);
3082 }
3083 
3084 static struct kernel_param_ops param_ops_max_slot_table_size = {
3085 	.set = param_set_max_slot_table_size,
3086 	.get = param_get_uint,
3087 };
3088 
3089 #define param_check_max_slot_table_size(name, p) \
3090 	__param_check(name, p, unsigned int);
3091 
3092 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3093 		   slot_table_size, 0644);
3094 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3095 		   max_slot_table_size, 0644);
3096 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3097 		   slot_table_size, 0644);
3098 
3099