xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision 06b5fc3ad94eebf25d5abc07f84e16b8b33dcf8c)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/net/sunrpc/xprtsock.c
4  *
5  * Client-side transport implementation for sockets.
6  *
7  * TCP callback races fixes (C) 1998 Red Hat
8  * TCP send fixes (C) 1998 Red Hat
9  * TCP NFS related read + write fixes
10  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
11  *
12  * Rewrite of larges part of the code in order to stabilize TCP stuff.
13  * Fix behaviour when socket buffer is full.
14  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
15  *
16  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
17  *
18  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
19  *   <gilles.quillard@bull.net>
20  */
21 
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/capability.h>
27 #include <linux/pagemap.h>
28 #include <linux/errno.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/net.h>
32 #include <linux/mm.h>
33 #include <linux/un.h>
34 #include <linux/udp.h>
35 #include <linux/tcp.h>
36 #include <linux/sunrpc/clnt.h>
37 #include <linux/sunrpc/addr.h>
38 #include <linux/sunrpc/sched.h>
39 #include <linux/sunrpc/svcsock.h>
40 #include <linux/sunrpc/xprtsock.h>
41 #include <linux/file.h>
42 #ifdef CONFIG_SUNRPC_BACKCHANNEL
43 #include <linux/sunrpc/bc_xprt.h>
44 #endif
45 
46 #include <net/sock.h>
47 #include <net/checksum.h>
48 #include <net/udp.h>
49 #include <net/tcp.h>
50 #include <linux/bvec.h>
51 #include <linux/highmem.h>
52 #include <linux/uio.h>
53 #include <linux/sched/mm.h>
54 
55 #include <trace/events/sunrpc.h>
56 
57 #include "sunrpc.h"
58 
59 static void xs_close(struct rpc_xprt *xprt);
60 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
61 		struct socket *sock);
62 
63 /*
64  * xprtsock tunables
65  */
66 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
67 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
68 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
69 
70 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
71 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
72 
73 #define XS_TCP_LINGER_TO	(15U * HZ)
74 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
75 
76 /*
77  * We can register our own files under /proc/sys/sunrpc by
78  * calling register_sysctl_table() again.  The files in that
79  * directory become the union of all files registered there.
80  *
81  * We simply need to make sure that we don't collide with
82  * someone else's file names!
83  */
84 
85 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
86 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
87 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
88 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
89 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
90 
91 static struct ctl_table_header *sunrpc_table_header;
92 
93 /*
94  * FIXME: changing the UDP slot table size should also resize the UDP
95  *        socket buffers for existing UDP transports
96  */
97 static struct ctl_table xs_tunables_table[] = {
98 	{
99 		.procname	= "udp_slot_table_entries",
100 		.data		= &xprt_udp_slot_table_entries,
101 		.maxlen		= sizeof(unsigned int),
102 		.mode		= 0644,
103 		.proc_handler	= proc_dointvec_minmax,
104 		.extra1		= &min_slot_table_size,
105 		.extra2		= &max_slot_table_size
106 	},
107 	{
108 		.procname	= "tcp_slot_table_entries",
109 		.data		= &xprt_tcp_slot_table_entries,
110 		.maxlen		= sizeof(unsigned int),
111 		.mode		= 0644,
112 		.proc_handler	= proc_dointvec_minmax,
113 		.extra1		= &min_slot_table_size,
114 		.extra2		= &max_slot_table_size
115 	},
116 	{
117 		.procname	= "tcp_max_slot_table_entries",
118 		.data		= &xprt_max_tcp_slot_table_entries,
119 		.maxlen		= sizeof(unsigned int),
120 		.mode		= 0644,
121 		.proc_handler	= proc_dointvec_minmax,
122 		.extra1		= &min_slot_table_size,
123 		.extra2		= &max_tcp_slot_table_limit
124 	},
125 	{
126 		.procname	= "min_resvport",
127 		.data		= &xprt_min_resvport,
128 		.maxlen		= sizeof(unsigned int),
129 		.mode		= 0644,
130 		.proc_handler	= proc_dointvec_minmax,
131 		.extra1		= &xprt_min_resvport_limit,
132 		.extra2		= &xprt_max_resvport_limit
133 	},
134 	{
135 		.procname	= "max_resvport",
136 		.data		= &xprt_max_resvport,
137 		.maxlen		= sizeof(unsigned int),
138 		.mode		= 0644,
139 		.proc_handler	= proc_dointvec_minmax,
140 		.extra1		= &xprt_min_resvport_limit,
141 		.extra2		= &xprt_max_resvport_limit
142 	},
143 	{
144 		.procname	= "tcp_fin_timeout",
145 		.data		= &xs_tcp_fin_timeout,
146 		.maxlen		= sizeof(xs_tcp_fin_timeout),
147 		.mode		= 0644,
148 		.proc_handler	= proc_dointvec_jiffies,
149 	},
150 	{ },
151 };
152 
153 static struct ctl_table sunrpc_table[] = {
154 	{
155 		.procname	= "sunrpc",
156 		.mode		= 0555,
157 		.child		= xs_tunables_table
158 	},
159 	{ },
160 };
161 
162 /*
163  * Wait duration for a reply from the RPC portmapper.
164  */
165 #define XS_BIND_TO		(60U * HZ)
166 
167 /*
168  * Delay if a UDP socket connect error occurs.  This is most likely some
169  * kind of resource problem on the local host.
170  */
171 #define XS_UDP_REEST_TO		(2U * HZ)
172 
173 /*
174  * The reestablish timeout allows clients to delay for a bit before attempting
175  * to reconnect to a server that just dropped our connection.
176  *
177  * We implement an exponential backoff when trying to reestablish a TCP
178  * transport connection with the server.  Some servers like to drop a TCP
179  * connection when they are overworked, so we start with a short timeout and
180  * increase over time if the server is down or not responding.
181  */
182 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
183 
184 /*
185  * TCP idle timeout; client drops the transport socket if it is idle
186  * for this long.  Note that we also timeout UDP sockets to prevent
187  * holding port numbers when there is no RPC traffic.
188  */
189 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
190 
191 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
192 # undef  RPC_DEBUG_DATA
193 # define RPCDBG_FACILITY	RPCDBG_TRANS
194 #endif
195 
196 #ifdef RPC_DEBUG_DATA
197 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
198 {
199 	u8 *buf = (u8 *) packet;
200 	int j;
201 
202 	dprintk("RPC:       %s\n", msg);
203 	for (j = 0; j < count && j < 128; j += 4) {
204 		if (!(j & 31)) {
205 			if (j)
206 				dprintk("\n");
207 			dprintk("0x%04x ", j);
208 		}
209 		dprintk("%02x%02x%02x%02x ",
210 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
211 	}
212 	dprintk("\n");
213 }
214 #else
215 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
216 {
217 	/* NOP */
218 }
219 #endif
220 
221 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
222 {
223 	return (struct rpc_xprt *) sk->sk_user_data;
224 }
225 
226 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
227 {
228 	return (struct sockaddr *) &xprt->addr;
229 }
230 
231 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
232 {
233 	return (struct sockaddr_un *) &xprt->addr;
234 }
235 
236 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
237 {
238 	return (struct sockaddr_in *) &xprt->addr;
239 }
240 
241 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
242 {
243 	return (struct sockaddr_in6 *) &xprt->addr;
244 }
245 
246 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
247 {
248 	struct sockaddr *sap = xs_addr(xprt);
249 	struct sockaddr_in6 *sin6;
250 	struct sockaddr_in *sin;
251 	struct sockaddr_un *sun;
252 	char buf[128];
253 
254 	switch (sap->sa_family) {
255 	case AF_LOCAL:
256 		sun = xs_addr_un(xprt);
257 		strlcpy(buf, sun->sun_path, sizeof(buf));
258 		xprt->address_strings[RPC_DISPLAY_ADDR] =
259 						kstrdup(buf, GFP_KERNEL);
260 		break;
261 	case AF_INET:
262 		(void)rpc_ntop(sap, buf, sizeof(buf));
263 		xprt->address_strings[RPC_DISPLAY_ADDR] =
264 						kstrdup(buf, GFP_KERNEL);
265 		sin = xs_addr_in(xprt);
266 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
267 		break;
268 	case AF_INET6:
269 		(void)rpc_ntop(sap, buf, sizeof(buf));
270 		xprt->address_strings[RPC_DISPLAY_ADDR] =
271 						kstrdup(buf, GFP_KERNEL);
272 		sin6 = xs_addr_in6(xprt);
273 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
274 		break;
275 	default:
276 		BUG();
277 	}
278 
279 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
280 }
281 
282 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
283 {
284 	struct sockaddr *sap = xs_addr(xprt);
285 	char buf[128];
286 
287 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
288 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
289 
290 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
291 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
292 }
293 
294 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
295 				     const char *protocol,
296 				     const char *netid)
297 {
298 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
299 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
300 	xs_format_common_peer_addresses(xprt);
301 	xs_format_common_peer_ports(xprt);
302 }
303 
304 static void xs_update_peer_port(struct rpc_xprt *xprt)
305 {
306 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
307 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
308 
309 	xs_format_common_peer_ports(xprt);
310 }
311 
312 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
313 {
314 	unsigned int i;
315 
316 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
317 		switch (i) {
318 		case RPC_DISPLAY_PROTO:
319 		case RPC_DISPLAY_NETID:
320 			continue;
321 		default:
322 			kfree(xprt->address_strings[i]);
323 		}
324 }
325 
326 static size_t
327 xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
328 {
329 	size_t i,n;
330 
331 	if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES))
332 		return want;
333 	n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT;
334 	for (i = 0; i < n; i++) {
335 		if (buf->pages[i])
336 			continue;
337 		buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp);
338 		if (!buf->pages[i]) {
339 			i *= PAGE_SIZE;
340 			return i > buf->page_base ? i - buf->page_base : 0;
341 		}
342 	}
343 	return want;
344 }
345 
346 static ssize_t
347 xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
348 {
349 	ssize_t ret;
350 	if (seek != 0)
351 		iov_iter_advance(&msg->msg_iter, seek);
352 	ret = sock_recvmsg(sock, msg, flags);
353 	return ret > 0 ? ret + seek : ret;
354 }
355 
356 static ssize_t
357 xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags,
358 		struct kvec *kvec, size_t count, size_t seek)
359 {
360 	iov_iter_kvec(&msg->msg_iter, READ, kvec, 1, count);
361 	return xs_sock_recvmsg(sock, msg, flags, seek);
362 }
363 
364 static ssize_t
365 xs_read_bvec(struct socket *sock, struct msghdr *msg, int flags,
366 		struct bio_vec *bvec, unsigned long nr, size_t count,
367 		size_t seek)
368 {
369 	iov_iter_bvec(&msg->msg_iter, READ, bvec, nr, count);
370 	return xs_sock_recvmsg(sock, msg, flags, seek);
371 }
372 
373 static ssize_t
374 xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
375 		size_t count)
376 {
377 	iov_iter_discard(&msg->msg_iter, READ, count);
378 	return sock_recvmsg(sock, msg, flags);
379 }
380 
381 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
382 static void
383 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
384 {
385 	struct bvec_iter bi = {
386 		.bi_size = count,
387 	};
388 	struct bio_vec bv;
389 
390 	bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
391 	for_each_bvec(bv, bvec, bi, bi)
392 		flush_dcache_page(bv.bv_page);
393 }
394 #else
395 static inline void
396 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
397 {
398 }
399 #endif
400 
401 static ssize_t
402 xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
403 		struct xdr_buf *buf, size_t count, size_t seek, size_t *read)
404 {
405 	size_t want, seek_init = seek, offset = 0;
406 	ssize_t ret;
407 
408 	want = min_t(size_t, count, buf->head[0].iov_len);
409 	if (seek < want) {
410 		ret = xs_read_kvec(sock, msg, flags, &buf->head[0], want, seek);
411 		if (ret <= 0)
412 			goto sock_err;
413 		offset += ret;
414 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
415 			goto out;
416 		if (ret != want)
417 			goto out;
418 		seek = 0;
419 	} else {
420 		seek -= want;
421 		offset += want;
422 	}
423 
424 	want = xs_alloc_sparse_pages(buf,
425 			min_t(size_t, count - offset, buf->page_len),
426 			GFP_NOWAIT);
427 	if (seek < want) {
428 		ret = xs_read_bvec(sock, msg, flags, buf->bvec,
429 				xdr_buf_pagecount(buf),
430 				want + buf->page_base,
431 				seek + buf->page_base);
432 		if (ret <= 0)
433 			goto sock_err;
434 		xs_flush_bvec(buf->bvec, ret, seek + buf->page_base);
435 		offset += ret - buf->page_base;
436 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
437 			goto out;
438 		if (ret != want)
439 			goto out;
440 		seek = 0;
441 	} else {
442 		seek -= want;
443 		offset += want;
444 	}
445 
446 	want = min_t(size_t, count - offset, buf->tail[0].iov_len);
447 	if (seek < want) {
448 		ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);
449 		if (ret <= 0)
450 			goto sock_err;
451 		offset += ret;
452 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
453 			goto out;
454 		if (ret != want)
455 			goto out;
456 	} else
457 		offset = seek_init;
458 	ret = -EMSGSIZE;
459 out:
460 	*read = offset - seek_init;
461 	return ret;
462 sock_err:
463 	offset += seek;
464 	goto out;
465 }
466 
467 static void
468 xs_read_header(struct sock_xprt *transport, struct xdr_buf *buf)
469 {
470 	if (!transport->recv.copied) {
471 		if (buf->head[0].iov_len >= transport->recv.offset)
472 			memcpy(buf->head[0].iov_base,
473 					&transport->recv.xid,
474 					transport->recv.offset);
475 		transport->recv.copied = transport->recv.offset;
476 	}
477 }
478 
479 static bool
480 xs_read_stream_request_done(struct sock_xprt *transport)
481 {
482 	return transport->recv.fraghdr & cpu_to_be32(RPC_LAST_STREAM_FRAGMENT);
483 }
484 
485 static void
486 xs_read_stream_check_eor(struct sock_xprt *transport,
487 		struct msghdr *msg)
488 {
489 	if (xs_read_stream_request_done(transport))
490 		msg->msg_flags |= MSG_EOR;
491 }
492 
493 static ssize_t
494 xs_read_stream_request(struct sock_xprt *transport, struct msghdr *msg,
495 		int flags, struct rpc_rqst *req)
496 {
497 	struct xdr_buf *buf = &req->rq_private_buf;
498 	size_t want, read;
499 	ssize_t ret;
500 
501 	xs_read_header(transport, buf);
502 
503 	want = transport->recv.len - transport->recv.offset;
504 	if (want != 0) {
505 		ret = xs_read_xdr_buf(transport->sock, msg, flags, buf,
506 				transport->recv.copied + want,
507 				transport->recv.copied,
508 				&read);
509 		transport->recv.offset += read;
510 		transport->recv.copied += read;
511 	}
512 
513 	if (transport->recv.offset == transport->recv.len)
514 		xs_read_stream_check_eor(transport, msg);
515 
516 	if (want == 0)
517 		return 0;
518 
519 	switch (ret) {
520 	default:
521 		break;
522 	case -EFAULT:
523 	case -EMSGSIZE:
524 		msg->msg_flags |= MSG_TRUNC;
525 		return read;
526 	case 0:
527 		return -ESHUTDOWN;
528 	}
529 	return ret < 0 ? ret : read;
530 }
531 
532 static size_t
533 xs_read_stream_headersize(bool isfrag)
534 {
535 	if (isfrag)
536 		return sizeof(__be32);
537 	return 3 * sizeof(__be32);
538 }
539 
540 static ssize_t
541 xs_read_stream_header(struct sock_xprt *transport, struct msghdr *msg,
542 		int flags, size_t want, size_t seek)
543 {
544 	struct kvec kvec = {
545 		.iov_base = &transport->recv.fraghdr,
546 		.iov_len = want,
547 	};
548 	return xs_read_kvec(transport->sock, msg, flags, &kvec, want, seek);
549 }
550 
551 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
552 static ssize_t
553 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
554 {
555 	struct rpc_xprt *xprt = &transport->xprt;
556 	struct rpc_rqst *req;
557 	ssize_t ret;
558 
559 	/* Look up and lock the request corresponding to the given XID */
560 	req = xprt_lookup_bc_request(xprt, transport->recv.xid);
561 	if (!req) {
562 		printk(KERN_WARNING "Callback slot table overflowed\n");
563 		return -ESHUTDOWN;
564 	}
565 
566 	ret = xs_read_stream_request(transport, msg, flags, req);
567 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
568 		xprt_complete_bc_request(req, transport->recv.copied);
569 
570 	return ret;
571 }
572 #else /* CONFIG_SUNRPC_BACKCHANNEL */
573 static ssize_t
574 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
575 {
576 	return -ESHUTDOWN;
577 }
578 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
579 
580 static ssize_t
581 xs_read_stream_reply(struct sock_xprt *transport, struct msghdr *msg, int flags)
582 {
583 	struct rpc_xprt *xprt = &transport->xprt;
584 	struct rpc_rqst *req;
585 	ssize_t ret = 0;
586 
587 	/* Look up and lock the request corresponding to the given XID */
588 	spin_lock(&xprt->queue_lock);
589 	req = xprt_lookup_rqst(xprt, transport->recv.xid);
590 	if (!req) {
591 		msg->msg_flags |= MSG_TRUNC;
592 		goto out;
593 	}
594 	xprt_pin_rqst(req);
595 	spin_unlock(&xprt->queue_lock);
596 
597 	ret = xs_read_stream_request(transport, msg, flags, req);
598 
599 	spin_lock(&xprt->queue_lock);
600 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
601 		xprt_complete_rqst(req->rq_task, transport->recv.copied);
602 	xprt_unpin_rqst(req);
603 out:
604 	spin_unlock(&xprt->queue_lock);
605 	return ret;
606 }
607 
608 static ssize_t
609 xs_read_stream(struct sock_xprt *transport, int flags)
610 {
611 	struct msghdr msg = { 0 };
612 	size_t want, read = 0;
613 	ssize_t ret = 0;
614 
615 	if (transport->recv.len == 0) {
616 		want = xs_read_stream_headersize(transport->recv.copied != 0);
617 		ret = xs_read_stream_header(transport, &msg, flags, want,
618 				transport->recv.offset);
619 		if (ret <= 0)
620 			goto out_err;
621 		transport->recv.offset = ret;
622 		if (transport->recv.offset != want)
623 			return transport->recv.offset;
624 		transport->recv.len = be32_to_cpu(transport->recv.fraghdr) &
625 			RPC_FRAGMENT_SIZE_MASK;
626 		transport->recv.offset -= sizeof(transport->recv.fraghdr);
627 		read = ret;
628 	}
629 
630 	switch (be32_to_cpu(transport->recv.calldir)) {
631 	default:
632 		msg.msg_flags |= MSG_TRUNC;
633 		break;
634 	case RPC_CALL:
635 		ret = xs_read_stream_call(transport, &msg, flags);
636 		break;
637 	case RPC_REPLY:
638 		ret = xs_read_stream_reply(transport, &msg, flags);
639 	}
640 	if (msg.msg_flags & MSG_TRUNC) {
641 		transport->recv.calldir = cpu_to_be32(-1);
642 		transport->recv.copied = -1;
643 	}
644 	if (ret < 0)
645 		goto out_err;
646 	read += ret;
647 	if (transport->recv.offset < transport->recv.len) {
648 		if (!(msg.msg_flags & MSG_TRUNC))
649 			return read;
650 		msg.msg_flags = 0;
651 		ret = xs_read_discard(transport->sock, &msg, flags,
652 				transport->recv.len - transport->recv.offset);
653 		if (ret <= 0)
654 			goto out_err;
655 		transport->recv.offset += ret;
656 		read += ret;
657 		if (transport->recv.offset != transport->recv.len)
658 			return read;
659 	}
660 	if (xs_read_stream_request_done(transport)) {
661 		trace_xs_stream_read_request(transport);
662 		transport->recv.copied = 0;
663 	}
664 	transport->recv.offset = 0;
665 	transport->recv.len = 0;
666 	return read;
667 out_err:
668 	return ret != 0 ? ret : -ESHUTDOWN;
669 }
670 
671 static __poll_t xs_poll_socket(struct sock_xprt *transport)
672 {
673 	return transport->sock->ops->poll(NULL, transport->sock, NULL);
674 }
675 
676 static bool xs_poll_socket_readable(struct sock_xprt *transport)
677 {
678 	__poll_t events = xs_poll_socket(transport);
679 
680 	return (events & (EPOLLIN | EPOLLRDNORM)) && !(events & EPOLLRDHUP);
681 }
682 
683 static void xs_poll_check_readable(struct sock_xprt *transport)
684 {
685 
686 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
687 	if (!xs_poll_socket_readable(transport))
688 		return;
689 	if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
690 		queue_work(xprtiod_workqueue, &transport->recv_worker);
691 }
692 
693 static void xs_stream_data_receive(struct sock_xprt *transport)
694 {
695 	size_t read = 0;
696 	ssize_t ret = 0;
697 
698 	mutex_lock(&transport->recv_mutex);
699 	if (transport->sock == NULL)
700 		goto out;
701 	for (;;) {
702 		ret = xs_read_stream(transport, MSG_DONTWAIT);
703 		if (ret < 0)
704 			break;
705 		read += ret;
706 		cond_resched();
707 	}
708 	if (ret == -ESHUTDOWN)
709 		kernel_sock_shutdown(transport->sock, SHUT_RDWR);
710 	else
711 		xs_poll_check_readable(transport);
712 out:
713 	mutex_unlock(&transport->recv_mutex);
714 	trace_xs_stream_read_data(&transport->xprt, ret, read);
715 }
716 
717 static void xs_stream_data_receive_workfn(struct work_struct *work)
718 {
719 	struct sock_xprt *transport =
720 		container_of(work, struct sock_xprt, recv_worker);
721 	unsigned int pflags = memalloc_nofs_save();
722 
723 	xs_stream_data_receive(transport);
724 	memalloc_nofs_restore(pflags);
725 }
726 
727 static void
728 xs_stream_reset_connect(struct sock_xprt *transport)
729 {
730 	transport->recv.offset = 0;
731 	transport->recv.len = 0;
732 	transport->recv.copied = 0;
733 	transport->xmit.offset = 0;
734 }
735 
736 static void
737 xs_stream_start_connect(struct sock_xprt *transport)
738 {
739 	transport->xprt.stat.connect_count++;
740 	transport->xprt.stat.connect_start = jiffies;
741 }
742 
743 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
744 
745 static int xs_sendmsg(struct socket *sock, struct msghdr *msg, size_t seek)
746 {
747 	if (seek)
748 		iov_iter_advance(&msg->msg_iter, seek);
749 	return sock_sendmsg(sock, msg);
750 }
751 
752 static int xs_send_kvec(struct socket *sock, struct msghdr *msg, struct kvec *vec, size_t seek)
753 {
754 	iov_iter_kvec(&msg->msg_iter, WRITE, vec, 1, vec->iov_len);
755 	return xs_sendmsg(sock, msg, seek);
756 }
757 
758 static int xs_send_pagedata(struct socket *sock, struct msghdr *msg, struct xdr_buf *xdr, size_t base)
759 {
760 	int err;
761 
762 	err = xdr_alloc_bvec(xdr, GFP_KERNEL);
763 	if (err < 0)
764 		return err;
765 
766 	iov_iter_bvec(&msg->msg_iter, WRITE, xdr->bvec,
767 			xdr_buf_pagecount(xdr),
768 			xdr->page_len + xdr->page_base);
769 	return xs_sendmsg(sock, msg, base + xdr->page_base);
770 }
771 
772 #define xs_record_marker_len() sizeof(rpc_fraghdr)
773 
774 /* Common case:
775  *  - stream transport
776  *  - sending from byte 0 of the message
777  *  - the message is wholly contained in @xdr's head iovec
778  */
779 static int xs_send_rm_and_kvec(struct socket *sock, struct msghdr *msg,
780 		rpc_fraghdr marker, struct kvec *vec, size_t base)
781 {
782 	struct kvec iov[2] = {
783 		[0] = {
784 			.iov_base	= &marker,
785 			.iov_len	= sizeof(marker)
786 		},
787 		[1] = *vec,
788 	};
789 	size_t len = iov[0].iov_len + iov[1].iov_len;
790 
791 	iov_iter_kvec(&msg->msg_iter, WRITE, iov, 2, len);
792 	return xs_sendmsg(sock, msg, base);
793 }
794 
795 /**
796  * xs_sendpages - write pages directly to a socket
797  * @sock: socket to send on
798  * @addr: UDP only -- address of destination
799  * @addrlen: UDP only -- length of destination address
800  * @xdr: buffer containing this request
801  * @base: starting position in the buffer
802  * @rm: stream record marker field
803  * @sent_p: return the total number of bytes successfully queued for sending
804  *
805  */
806 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, rpc_fraghdr rm, int *sent_p)
807 {
808 	struct msghdr msg = {
809 		.msg_name = addr,
810 		.msg_namelen = addrlen,
811 		.msg_flags = XS_SENDMSG_FLAGS | MSG_MORE,
812 	};
813 	unsigned int rmsize = rm ? sizeof(rm) : 0;
814 	unsigned int remainder = rmsize + xdr->len - base;
815 	unsigned int want;
816 	int err = 0;
817 
818 	if (unlikely(!sock))
819 		return -ENOTSOCK;
820 
821 	want = xdr->head[0].iov_len + rmsize;
822 	if (base < want) {
823 		unsigned int len = want - base;
824 		remainder -= len;
825 		if (remainder == 0)
826 			msg.msg_flags &= ~MSG_MORE;
827 		if (rmsize)
828 			err = xs_send_rm_and_kvec(sock, &msg, rm,
829 					&xdr->head[0], base);
830 		else
831 			err = xs_send_kvec(sock, &msg, &xdr->head[0], base);
832 		if (remainder == 0 || err != len)
833 			goto out;
834 		*sent_p += err;
835 		base = 0;
836 	} else
837 		base -= want;
838 
839 	if (base < xdr->page_len) {
840 		unsigned int len = xdr->page_len - base;
841 		remainder -= len;
842 		if (remainder == 0)
843 			msg.msg_flags &= ~MSG_MORE;
844 		err = xs_send_pagedata(sock, &msg, xdr, base);
845 		if (remainder == 0 || err != len)
846 			goto out;
847 		*sent_p += err;
848 		base = 0;
849 	} else
850 		base -= xdr->page_len;
851 
852 	if (base >= xdr->tail[0].iov_len)
853 		return 0;
854 	msg.msg_flags &= ~MSG_MORE;
855 	err = xs_send_kvec(sock, &msg, &xdr->tail[0], base);
856 out:
857 	if (err > 0) {
858 		*sent_p += err;
859 		err = 0;
860 	}
861 	return err;
862 }
863 
864 /**
865  * xs_nospace - handle transmit was incomplete
866  * @req: pointer to RPC request
867  *
868  */
869 static int xs_nospace(struct rpc_rqst *req)
870 {
871 	struct rpc_xprt *xprt = req->rq_xprt;
872 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
873 	struct sock *sk = transport->inet;
874 	int ret = -EAGAIN;
875 
876 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
877 			req->rq_task->tk_pid,
878 			req->rq_slen - transport->xmit.offset,
879 			req->rq_slen);
880 
881 	/* Protect against races with write_space */
882 	spin_lock_bh(&xprt->transport_lock);
883 
884 	/* Don't race with disconnect */
885 	if (xprt_connected(xprt)) {
886 		/* wait for more buffer space */
887 		sk->sk_write_pending++;
888 		xprt_wait_for_buffer_space(xprt);
889 	} else
890 		ret = -ENOTCONN;
891 
892 	spin_unlock_bh(&xprt->transport_lock);
893 
894 	/* Race breaker in case memory is freed before above code is called */
895 	if (ret == -EAGAIN) {
896 		struct socket_wq *wq;
897 
898 		rcu_read_lock();
899 		wq = rcu_dereference(sk->sk_wq);
900 		set_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags);
901 		rcu_read_unlock();
902 
903 		sk->sk_write_space(sk);
904 	}
905 	return ret;
906 }
907 
908 static void
909 xs_stream_prepare_request(struct rpc_rqst *req)
910 {
911 	req->rq_task->tk_status = xdr_alloc_bvec(&req->rq_rcv_buf, GFP_NOIO);
912 }
913 
914 /*
915  * Determine if the previous message in the stream was aborted before it
916  * could complete transmission.
917  */
918 static bool
919 xs_send_request_was_aborted(struct sock_xprt *transport, struct rpc_rqst *req)
920 {
921 	return transport->xmit.offset != 0 && req->rq_bytes_sent == 0;
922 }
923 
924 /*
925  * Return the stream record marker field for a record of length < 2^31-1
926  */
927 static rpc_fraghdr
928 xs_stream_record_marker(struct xdr_buf *xdr)
929 {
930 	if (!xdr->len)
931 		return 0;
932 	return cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | (u32)xdr->len);
933 }
934 
935 /**
936  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
937  * @req: pointer to RPC request
938  *
939  * Return values:
940  *        0:	The request has been sent
941  *   EAGAIN:	The socket was blocked, please call again later to
942  *		complete the request
943  * ENOTCONN:	Caller needs to invoke connect logic then call again
944  *    other:	Some other error occured, the request was not sent
945  */
946 static int xs_local_send_request(struct rpc_rqst *req)
947 {
948 	struct rpc_xprt *xprt = req->rq_xprt;
949 	struct sock_xprt *transport =
950 				container_of(xprt, struct sock_xprt, xprt);
951 	struct xdr_buf *xdr = &req->rq_snd_buf;
952 	int status;
953 	int sent = 0;
954 
955 	/* Close the stream if the previous transmission was incomplete */
956 	if (xs_send_request_was_aborted(transport, req)) {
957 		xs_close(xprt);
958 		return -ENOTCONN;
959 	}
960 
961 	xs_pktdump("packet data:",
962 			req->rq_svec->iov_base, req->rq_svec->iov_len);
963 
964 	req->rq_xtime = ktime_get();
965 	status = xs_sendpages(transport->sock, NULL, 0, xdr,
966 			      transport->xmit.offset,
967 			      xs_stream_record_marker(xdr),
968 			      &sent);
969 	dprintk("RPC:       %s(%u) = %d\n",
970 			__func__, xdr->len - transport->xmit.offset, status);
971 
972 	if (status == -EAGAIN && sock_writeable(transport->inet))
973 		status = -ENOBUFS;
974 
975 	if (likely(sent > 0) || status == 0) {
976 		transport->xmit.offset += sent;
977 		req->rq_bytes_sent = transport->xmit.offset;
978 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
979 			req->rq_xmit_bytes_sent += transport->xmit.offset;
980 			transport->xmit.offset = 0;
981 			return 0;
982 		}
983 		status = -EAGAIN;
984 	}
985 
986 	switch (status) {
987 	case -ENOBUFS:
988 		break;
989 	case -EAGAIN:
990 		status = xs_nospace(req);
991 		break;
992 	default:
993 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
994 			-status);
995 		/* fall through */
996 	case -EPIPE:
997 		xs_close(xprt);
998 		status = -ENOTCONN;
999 	}
1000 
1001 	return status;
1002 }
1003 
1004 /**
1005  * xs_udp_send_request - write an RPC request to a UDP socket
1006  * @req: pointer to RPC request
1007  *
1008  * Return values:
1009  *        0:	The request has been sent
1010  *   EAGAIN:	The socket was blocked, please call again later to
1011  *		complete the request
1012  * ENOTCONN:	Caller needs to invoke connect logic then call again
1013  *    other:	Some other error occurred, the request was not sent
1014  */
1015 static int xs_udp_send_request(struct rpc_rqst *req)
1016 {
1017 	struct rpc_xprt *xprt = req->rq_xprt;
1018 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1019 	struct xdr_buf *xdr = &req->rq_snd_buf;
1020 	int sent = 0;
1021 	int status;
1022 
1023 	xs_pktdump("packet data:",
1024 				req->rq_svec->iov_base,
1025 				req->rq_svec->iov_len);
1026 
1027 	if (!xprt_bound(xprt))
1028 		return -ENOTCONN;
1029 
1030 	if (!xprt_request_get_cong(xprt, req))
1031 		return -EBADSLT;
1032 
1033 	req->rq_xtime = ktime_get();
1034 	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
1035 			      xdr, 0, 0, &sent);
1036 
1037 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
1038 			xdr->len, status);
1039 
1040 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
1041 	if (status == -EPERM)
1042 		goto process_status;
1043 
1044 	if (status == -EAGAIN && sock_writeable(transport->inet))
1045 		status = -ENOBUFS;
1046 
1047 	if (sent > 0 || status == 0) {
1048 		req->rq_xmit_bytes_sent += sent;
1049 		if (sent >= req->rq_slen)
1050 			return 0;
1051 		/* Still some bytes left; set up for a retry later. */
1052 		status = -EAGAIN;
1053 	}
1054 
1055 process_status:
1056 	switch (status) {
1057 	case -ENOTSOCK:
1058 		status = -ENOTCONN;
1059 		/* Should we call xs_close() here? */
1060 		break;
1061 	case -EAGAIN:
1062 		status = xs_nospace(req);
1063 		break;
1064 	case -ENETUNREACH:
1065 	case -ENOBUFS:
1066 	case -EPIPE:
1067 	case -ECONNREFUSED:
1068 	case -EPERM:
1069 		/* When the server has died, an ICMP port unreachable message
1070 		 * prompts ECONNREFUSED. */
1071 		break;
1072 	default:
1073 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1074 			-status);
1075 	}
1076 
1077 	return status;
1078 }
1079 
1080 /**
1081  * xs_tcp_send_request - write an RPC request to a TCP socket
1082  * @req: pointer to RPC request
1083  *
1084  * Return values:
1085  *        0:	The request has been sent
1086  *   EAGAIN:	The socket was blocked, please call again later to
1087  *		complete the request
1088  * ENOTCONN:	Caller needs to invoke connect logic then call again
1089  *    other:	Some other error occurred, the request was not sent
1090  *
1091  * XXX: In the case of soft timeouts, should we eventually give up
1092  *	if sendmsg is not able to make progress?
1093  */
1094 static int xs_tcp_send_request(struct rpc_rqst *req)
1095 {
1096 	struct rpc_xprt *xprt = req->rq_xprt;
1097 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1098 	struct xdr_buf *xdr = &req->rq_snd_buf;
1099 	bool vm_wait = false;
1100 	int status;
1101 	int sent;
1102 
1103 	/* Close the stream if the previous transmission was incomplete */
1104 	if (xs_send_request_was_aborted(transport, req)) {
1105 		if (transport->sock != NULL)
1106 			kernel_sock_shutdown(transport->sock, SHUT_RDWR);
1107 		return -ENOTCONN;
1108 	}
1109 
1110 	xs_pktdump("packet data:",
1111 				req->rq_svec->iov_base,
1112 				req->rq_svec->iov_len);
1113 
1114 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
1115 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
1116 
1117 	/* Continue transmitting the packet/record. We must be careful
1118 	 * to cope with writespace callbacks arriving _after_ we have
1119 	 * called sendmsg(). */
1120 	req->rq_xtime = ktime_get();
1121 	while (1) {
1122 		sent = 0;
1123 		status = xs_sendpages(transport->sock, NULL, 0, xdr,
1124 				      transport->xmit.offset,
1125 				      xs_stream_record_marker(xdr),
1126 				      &sent);
1127 
1128 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
1129 				xdr->len - transport->xmit.offset, status);
1130 
1131 		/* If we've sent the entire packet, immediately
1132 		 * reset the count of bytes sent. */
1133 		transport->xmit.offset += sent;
1134 		req->rq_bytes_sent = transport->xmit.offset;
1135 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
1136 			req->rq_xmit_bytes_sent += transport->xmit.offset;
1137 			transport->xmit.offset = 0;
1138 			return 0;
1139 		}
1140 
1141 		WARN_ON_ONCE(sent == 0 && status == 0);
1142 
1143 		if (status == -EAGAIN ) {
1144 			/*
1145 			 * Return EAGAIN if we're sure we're hitting the
1146 			 * socket send buffer limits.
1147 			 */
1148 			if (test_bit(SOCK_NOSPACE, &transport->sock->flags))
1149 				break;
1150 			/*
1151 			 * Did we hit a memory allocation failure?
1152 			 */
1153 			if (sent == 0) {
1154 				status = -ENOBUFS;
1155 				if (vm_wait)
1156 					break;
1157 				/* Retry, knowing now that we're below the
1158 				 * socket send buffer limit
1159 				 */
1160 				vm_wait = true;
1161 			}
1162 			continue;
1163 		}
1164 		if (status < 0)
1165 			break;
1166 		vm_wait = false;
1167 	}
1168 
1169 	switch (status) {
1170 	case -ENOTSOCK:
1171 		status = -ENOTCONN;
1172 		/* Should we call xs_close() here? */
1173 		break;
1174 	case -EAGAIN:
1175 		status = xs_nospace(req);
1176 		break;
1177 	case -ECONNRESET:
1178 	case -ECONNREFUSED:
1179 	case -ENOTCONN:
1180 	case -EADDRINUSE:
1181 	case -ENOBUFS:
1182 	case -EPIPE:
1183 		break;
1184 	default:
1185 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1186 			-status);
1187 	}
1188 
1189 	return status;
1190 }
1191 
1192 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1193 {
1194 	transport->old_data_ready = sk->sk_data_ready;
1195 	transport->old_state_change = sk->sk_state_change;
1196 	transport->old_write_space = sk->sk_write_space;
1197 	transport->old_error_report = sk->sk_error_report;
1198 }
1199 
1200 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1201 {
1202 	sk->sk_data_ready = transport->old_data_ready;
1203 	sk->sk_state_change = transport->old_state_change;
1204 	sk->sk_write_space = transport->old_write_space;
1205 	sk->sk_error_report = transport->old_error_report;
1206 }
1207 
1208 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
1209 {
1210 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1211 
1212 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1213 }
1214 
1215 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1216 {
1217 	smp_mb__before_atomic();
1218 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1219 	clear_bit(XPRT_CLOSING, &xprt->state);
1220 	xs_sock_reset_state_flags(xprt);
1221 	smp_mb__after_atomic();
1222 }
1223 
1224 /**
1225  * xs_error_report - callback to handle TCP socket state errors
1226  * @sk: socket
1227  *
1228  * Note: we don't call sock_error() since there may be a rpc_task
1229  * using the socket, and so we don't want to clear sk->sk_err.
1230  */
1231 static void xs_error_report(struct sock *sk)
1232 {
1233 	struct rpc_xprt *xprt;
1234 	int err;
1235 
1236 	read_lock_bh(&sk->sk_callback_lock);
1237 	if (!(xprt = xprt_from_sock(sk)))
1238 		goto out;
1239 
1240 	err = -sk->sk_err;
1241 	if (err == 0)
1242 		goto out;
1243 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
1244 			xprt, -err);
1245 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
1246 	xprt_wake_pending_tasks(xprt, err);
1247  out:
1248 	read_unlock_bh(&sk->sk_callback_lock);
1249 }
1250 
1251 static void xs_reset_transport(struct sock_xprt *transport)
1252 {
1253 	struct socket *sock = transport->sock;
1254 	struct sock *sk = transport->inet;
1255 	struct rpc_xprt *xprt = &transport->xprt;
1256 
1257 	if (sk == NULL)
1258 		return;
1259 
1260 	if (atomic_read(&transport->xprt.swapper))
1261 		sk_clear_memalloc(sk);
1262 
1263 	kernel_sock_shutdown(sock, SHUT_RDWR);
1264 
1265 	mutex_lock(&transport->recv_mutex);
1266 	write_lock_bh(&sk->sk_callback_lock);
1267 	transport->inet = NULL;
1268 	transport->sock = NULL;
1269 
1270 	sk->sk_user_data = NULL;
1271 
1272 	xs_restore_old_callbacks(transport, sk);
1273 	xprt_clear_connected(xprt);
1274 	write_unlock_bh(&sk->sk_callback_lock);
1275 	xs_sock_reset_connection_flags(xprt);
1276 	/* Reset stream record info */
1277 	xs_stream_reset_connect(transport);
1278 	mutex_unlock(&transport->recv_mutex);
1279 
1280 	trace_rpc_socket_close(xprt, sock);
1281 	sock_release(sock);
1282 
1283 	xprt_disconnect_done(xprt);
1284 }
1285 
1286 /**
1287  * xs_close - close a socket
1288  * @xprt: transport
1289  *
1290  * This is used when all requests are complete; ie, no DRC state remains
1291  * on the server we want to save.
1292  *
1293  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
1294  * xs_reset_transport() zeroing the socket from underneath a writer.
1295  */
1296 static void xs_close(struct rpc_xprt *xprt)
1297 {
1298 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1299 
1300 	dprintk("RPC:       xs_close xprt %p\n", xprt);
1301 
1302 	xs_reset_transport(transport);
1303 	xprt->reestablish_timeout = 0;
1304 }
1305 
1306 static void xs_inject_disconnect(struct rpc_xprt *xprt)
1307 {
1308 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
1309 		xprt);
1310 	xprt_disconnect_done(xprt);
1311 }
1312 
1313 static void xs_xprt_free(struct rpc_xprt *xprt)
1314 {
1315 	xs_free_peer_addresses(xprt);
1316 	xprt_free(xprt);
1317 }
1318 
1319 /**
1320  * xs_destroy - prepare to shutdown a transport
1321  * @xprt: doomed transport
1322  *
1323  */
1324 static void xs_destroy(struct rpc_xprt *xprt)
1325 {
1326 	struct sock_xprt *transport = container_of(xprt,
1327 			struct sock_xprt, xprt);
1328 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
1329 
1330 	cancel_delayed_work_sync(&transport->connect_worker);
1331 	xs_close(xprt);
1332 	cancel_work_sync(&transport->recv_worker);
1333 	xs_xprt_free(xprt);
1334 	module_put(THIS_MODULE);
1335 }
1336 
1337 /**
1338  * xs_udp_data_read_skb - receive callback for UDP sockets
1339  * @xprt: transport
1340  * @sk: socket
1341  * @skb: skbuff
1342  *
1343  */
1344 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1345 		struct sock *sk,
1346 		struct sk_buff *skb)
1347 {
1348 	struct rpc_task *task;
1349 	struct rpc_rqst *rovr;
1350 	int repsize, copied;
1351 	u32 _xid;
1352 	__be32 *xp;
1353 
1354 	repsize = skb->len;
1355 	if (repsize < 4) {
1356 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1357 		return;
1358 	}
1359 
1360 	/* Copy the XID from the skb... */
1361 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1362 	if (xp == NULL)
1363 		return;
1364 
1365 	/* Look up and lock the request corresponding to the given XID */
1366 	spin_lock(&xprt->queue_lock);
1367 	rovr = xprt_lookup_rqst(xprt, *xp);
1368 	if (!rovr)
1369 		goto out_unlock;
1370 	xprt_pin_rqst(rovr);
1371 	xprt_update_rtt(rovr->rq_task);
1372 	spin_unlock(&xprt->queue_lock);
1373 	task = rovr->rq_task;
1374 
1375 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1376 		copied = repsize;
1377 
1378 	/* Suck it into the iovec, verify checksum if not done by hw. */
1379 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1380 		spin_lock(&xprt->queue_lock);
1381 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1382 		goto out_unpin;
1383 	}
1384 
1385 
1386 	spin_lock_bh(&xprt->transport_lock);
1387 	xprt_adjust_cwnd(xprt, task, copied);
1388 	spin_unlock_bh(&xprt->transport_lock);
1389 	spin_lock(&xprt->queue_lock);
1390 	xprt_complete_rqst(task, copied);
1391 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1392 out_unpin:
1393 	xprt_unpin_rqst(rovr);
1394  out_unlock:
1395 	spin_unlock(&xprt->queue_lock);
1396 }
1397 
1398 static void xs_udp_data_receive(struct sock_xprt *transport)
1399 {
1400 	struct sk_buff *skb;
1401 	struct sock *sk;
1402 	int err;
1403 
1404 	mutex_lock(&transport->recv_mutex);
1405 	sk = transport->inet;
1406 	if (sk == NULL)
1407 		goto out;
1408 	for (;;) {
1409 		skb = skb_recv_udp(sk, 0, 1, &err);
1410 		if (skb == NULL)
1411 			break;
1412 		xs_udp_data_read_skb(&transport->xprt, sk, skb);
1413 		consume_skb(skb);
1414 		cond_resched();
1415 	}
1416 	xs_poll_check_readable(transport);
1417 out:
1418 	mutex_unlock(&transport->recv_mutex);
1419 }
1420 
1421 static void xs_udp_data_receive_workfn(struct work_struct *work)
1422 {
1423 	struct sock_xprt *transport =
1424 		container_of(work, struct sock_xprt, recv_worker);
1425 	unsigned int pflags = memalloc_nofs_save();
1426 
1427 	xs_udp_data_receive(transport);
1428 	memalloc_nofs_restore(pflags);
1429 }
1430 
1431 /**
1432  * xs_data_ready - "data ready" callback for UDP sockets
1433  * @sk: socket with data to read
1434  *
1435  */
1436 static void xs_data_ready(struct sock *sk)
1437 {
1438 	struct rpc_xprt *xprt;
1439 
1440 	read_lock_bh(&sk->sk_callback_lock);
1441 	dprintk("RPC:       xs_data_ready...\n");
1442 	xprt = xprt_from_sock(sk);
1443 	if (xprt != NULL) {
1444 		struct sock_xprt *transport = container_of(xprt,
1445 				struct sock_xprt, xprt);
1446 		transport->old_data_ready(sk);
1447 		/* Any data means we had a useful conversation, so
1448 		 * then we don't need to delay the next reconnect
1449 		 */
1450 		if (xprt->reestablish_timeout)
1451 			xprt->reestablish_timeout = 0;
1452 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1453 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1454 	}
1455 	read_unlock_bh(&sk->sk_callback_lock);
1456 }
1457 
1458 /*
1459  * Helper function to force a TCP close if the server is sending
1460  * junk and/or it has put us in CLOSE_WAIT
1461  */
1462 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1463 {
1464 	xprt_force_disconnect(xprt);
1465 }
1466 
1467 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1468 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1469 {
1470 	return PAGE_SIZE;
1471 }
1472 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1473 
1474 /**
1475  * xs_tcp_state_change - callback to handle TCP socket state changes
1476  * @sk: socket whose state has changed
1477  *
1478  */
1479 static void xs_tcp_state_change(struct sock *sk)
1480 {
1481 	struct rpc_xprt *xprt;
1482 	struct sock_xprt *transport;
1483 
1484 	read_lock_bh(&sk->sk_callback_lock);
1485 	if (!(xprt = xprt_from_sock(sk)))
1486 		goto out;
1487 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1488 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1489 			sk->sk_state, xprt_connected(xprt),
1490 			sock_flag(sk, SOCK_DEAD),
1491 			sock_flag(sk, SOCK_ZAPPED),
1492 			sk->sk_shutdown);
1493 
1494 	transport = container_of(xprt, struct sock_xprt, xprt);
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 			xprt->connect_cookie++;
1501 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1502 			xprt_clear_connecting(xprt);
1503 
1504 			xprt->stat.connect_count++;
1505 			xprt->stat.connect_time += (long)jiffies -
1506 						   xprt->stat.connect_start;
1507 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1508 		}
1509 		spin_unlock(&xprt->transport_lock);
1510 		break;
1511 	case TCP_FIN_WAIT1:
1512 		/* The client initiated a shutdown of the socket */
1513 		xprt->connect_cookie++;
1514 		xprt->reestablish_timeout = 0;
1515 		set_bit(XPRT_CLOSING, &xprt->state);
1516 		smp_mb__before_atomic();
1517 		clear_bit(XPRT_CONNECTED, &xprt->state);
1518 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1519 		smp_mb__after_atomic();
1520 		break;
1521 	case TCP_CLOSE_WAIT:
1522 		/* The server initiated a shutdown of the socket */
1523 		xprt->connect_cookie++;
1524 		clear_bit(XPRT_CONNECTED, &xprt->state);
1525 		xs_tcp_force_close(xprt);
1526 		/* fall through */
1527 	case TCP_CLOSING:
1528 		/*
1529 		 * If the server closed down the connection, make sure that
1530 		 * we back off before reconnecting
1531 		 */
1532 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1533 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1534 		break;
1535 	case TCP_LAST_ACK:
1536 		set_bit(XPRT_CLOSING, &xprt->state);
1537 		smp_mb__before_atomic();
1538 		clear_bit(XPRT_CONNECTED, &xprt->state);
1539 		smp_mb__after_atomic();
1540 		break;
1541 	case TCP_CLOSE:
1542 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1543 					&transport->sock_state))
1544 			xprt_clear_connecting(xprt);
1545 		clear_bit(XPRT_CLOSING, &xprt->state);
1546 		/* Trigger the socket release */
1547 		xs_tcp_force_close(xprt);
1548 	}
1549  out:
1550 	read_unlock_bh(&sk->sk_callback_lock);
1551 }
1552 
1553 static void xs_write_space(struct sock *sk)
1554 {
1555 	struct socket_wq *wq;
1556 	struct rpc_xprt *xprt;
1557 
1558 	if (!sk->sk_socket)
1559 		return;
1560 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1561 
1562 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1563 		return;
1564 	rcu_read_lock();
1565 	wq = rcu_dereference(sk->sk_wq);
1566 	if (!wq || test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags) == 0)
1567 		goto out;
1568 
1569 	if (xprt_write_space(xprt))
1570 		sk->sk_write_pending--;
1571 out:
1572 	rcu_read_unlock();
1573 }
1574 
1575 /**
1576  * xs_udp_write_space - callback invoked when socket buffer space
1577  *                             becomes available
1578  * @sk: socket whose state has changed
1579  *
1580  * Called when more output buffer space is available for this socket.
1581  * We try not to wake our writers until they can make "significant"
1582  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1583  * with a bunch of small requests.
1584  */
1585 static void xs_udp_write_space(struct sock *sk)
1586 {
1587 	read_lock_bh(&sk->sk_callback_lock);
1588 
1589 	/* from net/core/sock.c:sock_def_write_space */
1590 	if (sock_writeable(sk))
1591 		xs_write_space(sk);
1592 
1593 	read_unlock_bh(&sk->sk_callback_lock);
1594 }
1595 
1596 /**
1597  * xs_tcp_write_space - callback invoked when socket buffer space
1598  *                             becomes available
1599  * @sk: socket whose state has changed
1600  *
1601  * Called when more output buffer space is available for this socket.
1602  * We try not to wake our writers until they can make "significant"
1603  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1604  * with a bunch of small requests.
1605  */
1606 static void xs_tcp_write_space(struct sock *sk)
1607 {
1608 	read_lock_bh(&sk->sk_callback_lock);
1609 
1610 	/* from net/core/stream.c:sk_stream_write_space */
1611 	if (sk_stream_is_writeable(sk))
1612 		xs_write_space(sk);
1613 
1614 	read_unlock_bh(&sk->sk_callback_lock);
1615 }
1616 
1617 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1618 {
1619 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1620 	struct sock *sk = transport->inet;
1621 
1622 	if (transport->rcvsize) {
1623 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1624 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1625 	}
1626 	if (transport->sndsize) {
1627 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1628 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1629 		sk->sk_write_space(sk);
1630 	}
1631 }
1632 
1633 /**
1634  * xs_udp_set_buffer_size - set send and receive limits
1635  * @xprt: generic transport
1636  * @sndsize: requested size of send buffer, in bytes
1637  * @rcvsize: requested size of receive buffer, in bytes
1638  *
1639  * Set socket send and receive buffer size limits.
1640  */
1641 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1642 {
1643 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1644 
1645 	transport->sndsize = 0;
1646 	if (sndsize)
1647 		transport->sndsize = sndsize + 1024;
1648 	transport->rcvsize = 0;
1649 	if (rcvsize)
1650 		transport->rcvsize = rcvsize + 1024;
1651 
1652 	xs_udp_do_set_buffer_size(xprt);
1653 }
1654 
1655 /**
1656  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1657  * @xprt: controlling transport
1658  * @task: task that timed out
1659  *
1660  * Adjust the congestion window after a retransmit timeout has occurred.
1661  */
1662 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1663 {
1664 	spin_lock_bh(&xprt->transport_lock);
1665 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1666 	spin_unlock_bh(&xprt->transport_lock);
1667 }
1668 
1669 static int xs_get_random_port(void)
1670 {
1671 	unsigned short min = xprt_min_resvport, max = xprt_max_resvport;
1672 	unsigned short range;
1673 	unsigned short rand;
1674 
1675 	if (max < min)
1676 		return -EADDRINUSE;
1677 	range = max - min + 1;
1678 	rand = (unsigned short) prandom_u32() % range;
1679 	return rand + min;
1680 }
1681 
1682 /**
1683  * xs_set_reuseaddr_port - set the socket's port and address reuse options
1684  * @sock: socket
1685  *
1686  * Note that this function has to be called on all sockets that share the
1687  * same port, and it must be called before binding.
1688  */
1689 static void xs_sock_set_reuseport(struct socket *sock)
1690 {
1691 	int opt = 1;
1692 
1693 	kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
1694 			(char *)&opt, sizeof(opt));
1695 }
1696 
1697 static unsigned short xs_sock_getport(struct socket *sock)
1698 {
1699 	struct sockaddr_storage buf;
1700 	unsigned short port = 0;
1701 
1702 	if (kernel_getsockname(sock, (struct sockaddr *)&buf) < 0)
1703 		goto out;
1704 	switch (buf.ss_family) {
1705 	case AF_INET6:
1706 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1707 		break;
1708 	case AF_INET:
1709 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1710 	}
1711 out:
1712 	return port;
1713 }
1714 
1715 /**
1716  * xs_set_port - reset the port number in the remote endpoint address
1717  * @xprt: generic transport
1718  * @port: new port number
1719  *
1720  */
1721 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1722 {
1723 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1724 
1725 	rpc_set_port(xs_addr(xprt), port);
1726 	xs_update_peer_port(xprt);
1727 }
1728 
1729 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1730 {
1731 	if (transport->srcport == 0)
1732 		transport->srcport = xs_sock_getport(sock);
1733 }
1734 
1735 static int xs_get_srcport(struct sock_xprt *transport)
1736 {
1737 	int port = transport->srcport;
1738 
1739 	if (port == 0 && transport->xprt.resvport)
1740 		port = xs_get_random_port();
1741 	return port;
1742 }
1743 
1744 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1745 {
1746 	if (transport->srcport != 0)
1747 		transport->srcport = 0;
1748 	if (!transport->xprt.resvport)
1749 		return 0;
1750 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1751 		return xprt_max_resvport;
1752 	return --port;
1753 }
1754 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1755 {
1756 	struct sockaddr_storage myaddr;
1757 	int err, nloop = 0;
1758 	int port = xs_get_srcport(transport);
1759 	unsigned short last;
1760 
1761 	/*
1762 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1763 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1764 	 * port selection happen implicitly when the socket is used
1765 	 * (for example at connect time).
1766 	 *
1767 	 * This ensures that we can continue to establish TCP
1768 	 * connections even when all local ephemeral ports are already
1769 	 * a part of some TCP connection.  This makes no difference
1770 	 * for UDP sockets, but also doens't harm them.
1771 	 *
1772 	 * If we're asking for any reserved port (i.e. port == 0 &&
1773 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1774 	 * ensure that port is non-zero and we will bind as needed.
1775 	 */
1776 	if (port <= 0)
1777 		return port;
1778 
1779 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1780 	do {
1781 		rpc_set_port((struct sockaddr *)&myaddr, port);
1782 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1783 				transport->xprt.addrlen);
1784 		if (err == 0) {
1785 			transport->srcport = port;
1786 			break;
1787 		}
1788 		last = port;
1789 		port = xs_next_srcport(transport, port);
1790 		if (port > last)
1791 			nloop++;
1792 	} while (err == -EADDRINUSE && nloop != 2);
1793 
1794 	if (myaddr.ss_family == AF_INET)
1795 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1796 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1797 				port, err ? "failed" : "ok", err);
1798 	else
1799 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1800 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1801 				port, err ? "failed" : "ok", err);
1802 	return err;
1803 }
1804 
1805 /*
1806  * We don't support autobind on AF_LOCAL sockets
1807  */
1808 static void xs_local_rpcbind(struct rpc_task *task)
1809 {
1810 	xprt_set_bound(task->tk_xprt);
1811 }
1812 
1813 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1814 {
1815 }
1816 
1817 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1818 static struct lock_class_key xs_key[2];
1819 static struct lock_class_key xs_slock_key[2];
1820 
1821 static inline void xs_reclassify_socketu(struct socket *sock)
1822 {
1823 	struct sock *sk = sock->sk;
1824 
1825 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1826 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1827 }
1828 
1829 static inline void xs_reclassify_socket4(struct socket *sock)
1830 {
1831 	struct sock *sk = sock->sk;
1832 
1833 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1834 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1835 }
1836 
1837 static inline void xs_reclassify_socket6(struct socket *sock)
1838 {
1839 	struct sock *sk = sock->sk;
1840 
1841 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1842 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1843 }
1844 
1845 static inline void xs_reclassify_socket(int family, struct socket *sock)
1846 {
1847 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1848 		return;
1849 
1850 	switch (family) {
1851 	case AF_LOCAL:
1852 		xs_reclassify_socketu(sock);
1853 		break;
1854 	case AF_INET:
1855 		xs_reclassify_socket4(sock);
1856 		break;
1857 	case AF_INET6:
1858 		xs_reclassify_socket6(sock);
1859 		break;
1860 	}
1861 }
1862 #else
1863 static inline void xs_reclassify_socket(int family, struct socket *sock)
1864 {
1865 }
1866 #endif
1867 
1868 static void xs_dummy_setup_socket(struct work_struct *work)
1869 {
1870 }
1871 
1872 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1873 		struct sock_xprt *transport, int family, int type,
1874 		int protocol, bool reuseport)
1875 {
1876 	struct socket *sock;
1877 	int err;
1878 
1879 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1880 	if (err < 0) {
1881 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1882 				protocol, -err);
1883 		goto out;
1884 	}
1885 	xs_reclassify_socket(family, sock);
1886 
1887 	if (reuseport)
1888 		xs_sock_set_reuseport(sock);
1889 
1890 	err = xs_bind(transport, sock);
1891 	if (err) {
1892 		sock_release(sock);
1893 		goto out;
1894 	}
1895 
1896 	return sock;
1897 out:
1898 	return ERR_PTR(err);
1899 }
1900 
1901 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1902 				      struct socket *sock)
1903 {
1904 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1905 									xprt);
1906 
1907 	if (!transport->inet) {
1908 		struct sock *sk = sock->sk;
1909 
1910 		write_lock_bh(&sk->sk_callback_lock);
1911 
1912 		xs_save_old_callbacks(transport, sk);
1913 
1914 		sk->sk_user_data = xprt;
1915 		sk->sk_data_ready = xs_data_ready;
1916 		sk->sk_write_space = xs_udp_write_space;
1917 		sock_set_flag(sk, SOCK_FASYNC);
1918 		sk->sk_error_report = xs_error_report;
1919 
1920 		xprt_clear_connected(xprt);
1921 
1922 		/* Reset to new socket */
1923 		transport->sock = sock;
1924 		transport->inet = sk;
1925 
1926 		write_unlock_bh(&sk->sk_callback_lock);
1927 	}
1928 
1929 	xs_stream_start_connect(transport);
1930 
1931 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1932 }
1933 
1934 /**
1935  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1936  * @transport: socket transport to connect
1937  */
1938 static int xs_local_setup_socket(struct sock_xprt *transport)
1939 {
1940 	struct rpc_xprt *xprt = &transport->xprt;
1941 	struct socket *sock;
1942 	int status = -EIO;
1943 
1944 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1945 					SOCK_STREAM, 0, &sock, 1);
1946 	if (status < 0) {
1947 		dprintk("RPC:       can't create AF_LOCAL "
1948 			"transport socket (%d).\n", -status);
1949 		goto out;
1950 	}
1951 	xs_reclassify_socket(AF_LOCAL, sock);
1952 
1953 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1954 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1955 
1956 	status = xs_local_finish_connecting(xprt, sock);
1957 	trace_rpc_socket_connect(xprt, sock, status);
1958 	switch (status) {
1959 	case 0:
1960 		dprintk("RPC:       xprt %p connected to %s\n",
1961 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1962 		xprt->stat.connect_count++;
1963 		xprt->stat.connect_time += (long)jiffies -
1964 					   xprt->stat.connect_start;
1965 		xprt_set_connected(xprt);
1966 	case -ENOBUFS:
1967 		break;
1968 	case -ENOENT:
1969 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1970 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1971 		break;
1972 	case -ECONNREFUSED:
1973 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1974 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1975 		break;
1976 	default:
1977 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1978 				__func__, -status,
1979 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1980 	}
1981 
1982 out:
1983 	xprt_clear_connecting(xprt);
1984 	xprt_wake_pending_tasks(xprt, status);
1985 	return status;
1986 }
1987 
1988 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1989 {
1990 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1991 	int ret;
1992 
1993 	 if (RPC_IS_ASYNC(task)) {
1994 		/*
1995 		 * We want the AF_LOCAL connect to be resolved in the
1996 		 * filesystem namespace of the process making the rpc
1997 		 * call.  Thus we connect synchronously.
1998 		 *
1999 		 * If we want to support asynchronous AF_LOCAL calls,
2000 		 * we'll need to figure out how to pass a namespace to
2001 		 * connect.
2002 		 */
2003 		rpc_exit(task, -ENOTCONN);
2004 		return;
2005 	}
2006 	ret = xs_local_setup_socket(transport);
2007 	if (ret && !RPC_IS_SOFTCONN(task))
2008 		msleep_interruptible(15000);
2009 }
2010 
2011 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2012 /*
2013  * Note that this should be called with XPRT_LOCKED held (or when we otherwise
2014  * know that we have exclusive access to the socket), to guard against
2015  * races with xs_reset_transport.
2016  */
2017 static void xs_set_memalloc(struct rpc_xprt *xprt)
2018 {
2019 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2020 			xprt);
2021 
2022 	/*
2023 	 * If there's no sock, then we have nothing to set. The
2024 	 * reconnecting process will get it for us.
2025 	 */
2026 	if (!transport->inet)
2027 		return;
2028 	if (atomic_read(&xprt->swapper))
2029 		sk_set_memalloc(transport->inet);
2030 }
2031 
2032 /**
2033  * xs_enable_swap - Tag this transport as being used for swap.
2034  * @xprt: transport to tag
2035  *
2036  * Take a reference to this transport on behalf of the rpc_clnt, and
2037  * optionally mark it for swapping if it wasn't already.
2038  */
2039 static int
2040 xs_enable_swap(struct rpc_xprt *xprt)
2041 {
2042 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2043 
2044 	if (atomic_inc_return(&xprt->swapper) != 1)
2045 		return 0;
2046 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2047 		return -ERESTARTSYS;
2048 	if (xs->inet)
2049 		sk_set_memalloc(xs->inet);
2050 	xprt_release_xprt(xprt, NULL);
2051 	return 0;
2052 }
2053 
2054 /**
2055  * xs_disable_swap - Untag this transport as being used for swap.
2056  * @xprt: transport to tag
2057  *
2058  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2059  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2060  */
2061 static void
2062 xs_disable_swap(struct rpc_xprt *xprt)
2063 {
2064 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2065 
2066 	if (!atomic_dec_and_test(&xprt->swapper))
2067 		return;
2068 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
2069 		return;
2070 	if (xs->inet)
2071 		sk_clear_memalloc(xs->inet);
2072 	xprt_release_xprt(xprt, NULL);
2073 }
2074 #else
2075 static void xs_set_memalloc(struct rpc_xprt *xprt)
2076 {
2077 }
2078 
2079 static int
2080 xs_enable_swap(struct rpc_xprt *xprt)
2081 {
2082 	return -EINVAL;
2083 }
2084 
2085 static void
2086 xs_disable_swap(struct rpc_xprt *xprt)
2087 {
2088 }
2089 #endif
2090 
2091 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2092 {
2093 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2094 
2095 	if (!transport->inet) {
2096 		struct sock *sk = sock->sk;
2097 
2098 		write_lock_bh(&sk->sk_callback_lock);
2099 
2100 		xs_save_old_callbacks(transport, sk);
2101 
2102 		sk->sk_user_data = xprt;
2103 		sk->sk_data_ready = xs_data_ready;
2104 		sk->sk_write_space = xs_udp_write_space;
2105 		sock_set_flag(sk, SOCK_FASYNC);
2106 
2107 		xprt_set_connected(xprt);
2108 
2109 		/* Reset to new socket */
2110 		transport->sock = sock;
2111 		transport->inet = sk;
2112 
2113 		xs_set_memalloc(xprt);
2114 
2115 		write_unlock_bh(&sk->sk_callback_lock);
2116 	}
2117 	xs_udp_do_set_buffer_size(xprt);
2118 
2119 	xprt->stat.connect_start = jiffies;
2120 }
2121 
2122 static void xs_udp_setup_socket(struct work_struct *work)
2123 {
2124 	struct sock_xprt *transport =
2125 		container_of(work, struct sock_xprt, connect_worker.work);
2126 	struct rpc_xprt *xprt = &transport->xprt;
2127 	struct socket *sock;
2128 	int status = -EIO;
2129 
2130 	sock = xs_create_sock(xprt, transport,
2131 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2132 			IPPROTO_UDP, false);
2133 	if (IS_ERR(sock))
2134 		goto out;
2135 
2136 	dprintk("RPC:       worker connecting xprt %p via %s to "
2137 				"%s (port %s)\n", xprt,
2138 			xprt->address_strings[RPC_DISPLAY_PROTO],
2139 			xprt->address_strings[RPC_DISPLAY_ADDR],
2140 			xprt->address_strings[RPC_DISPLAY_PORT]);
2141 
2142 	xs_udp_finish_connecting(xprt, sock);
2143 	trace_rpc_socket_connect(xprt, sock, 0);
2144 	status = 0;
2145 out:
2146 	xprt_clear_connecting(xprt);
2147 	xprt_unlock_connect(xprt, transport);
2148 	xprt_wake_pending_tasks(xprt, status);
2149 }
2150 
2151 /**
2152  * xs_tcp_shutdown - gracefully shut down a TCP socket
2153  * @xprt: transport
2154  *
2155  * Initiates a graceful shutdown of the TCP socket by calling the
2156  * equivalent of shutdown(SHUT_RDWR);
2157  */
2158 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2159 {
2160 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2161 	struct socket *sock = transport->sock;
2162 	int skst = transport->inet ? transport->inet->sk_state : TCP_CLOSE;
2163 
2164 	if (sock == NULL)
2165 		return;
2166 	switch (skst) {
2167 	default:
2168 		kernel_sock_shutdown(sock, SHUT_RDWR);
2169 		trace_rpc_socket_shutdown(xprt, sock);
2170 		break;
2171 	case TCP_CLOSE:
2172 	case TCP_TIME_WAIT:
2173 		xs_reset_transport(transport);
2174 	}
2175 }
2176 
2177 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2178 		struct socket *sock)
2179 {
2180 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2181 	unsigned int keepidle;
2182 	unsigned int keepcnt;
2183 	unsigned int opt_on = 1;
2184 	unsigned int timeo;
2185 
2186 	spin_lock_bh(&xprt->transport_lock);
2187 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2188 	keepcnt = xprt->timeout->to_retries + 1;
2189 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2190 		(xprt->timeout->to_retries + 1);
2191 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2192 	spin_unlock_bh(&xprt->transport_lock);
2193 
2194 	/* TCP Keepalive options */
2195 	kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
2196 			(char *)&opt_on, sizeof(opt_on));
2197 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
2198 			(char *)&keepidle, sizeof(keepidle));
2199 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
2200 			(char *)&keepidle, sizeof(keepidle));
2201 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
2202 			(char *)&keepcnt, sizeof(keepcnt));
2203 
2204 	/* TCP user timeout (see RFC5482) */
2205 	kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
2206 			(char *)&timeo, sizeof(timeo));
2207 }
2208 
2209 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2210 		unsigned long connect_timeout,
2211 		unsigned long reconnect_timeout)
2212 {
2213 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2214 	struct rpc_timeout to;
2215 	unsigned long initval;
2216 
2217 	spin_lock_bh(&xprt->transport_lock);
2218 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2219 		xprt->max_reconnect_timeout = reconnect_timeout;
2220 	if (connect_timeout < xprt->connect_timeout) {
2221 		memcpy(&to, xprt->timeout, sizeof(to));
2222 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2223 		/* Arbitrary lower limit */
2224 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2225 			initval = XS_TCP_INIT_REEST_TO << 1;
2226 		to.to_initval = initval;
2227 		to.to_maxval = initval;
2228 		memcpy(&transport->tcp_timeout, &to,
2229 				sizeof(transport->tcp_timeout));
2230 		xprt->timeout = &transport->tcp_timeout;
2231 		xprt->connect_timeout = connect_timeout;
2232 	}
2233 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2234 	spin_unlock_bh(&xprt->transport_lock);
2235 }
2236 
2237 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2238 {
2239 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2240 	int ret = -ENOTCONN;
2241 
2242 	if (!transport->inet) {
2243 		struct sock *sk = sock->sk;
2244 		unsigned int addr_pref = IPV6_PREFER_SRC_PUBLIC;
2245 
2246 		/* Avoid temporary address, they are bad for long-lived
2247 		 * connections such as NFS mounts.
2248 		 * RFC4941, section 3.6 suggests that:
2249 		 *    Individual applications, which have specific
2250 		 *    knowledge about the normal duration of connections,
2251 		 *    MAY override this as appropriate.
2252 		 */
2253 		kernel_setsockopt(sock, SOL_IPV6, IPV6_ADDR_PREFERENCES,
2254 				(char *)&addr_pref, sizeof(addr_pref));
2255 
2256 		xs_tcp_set_socket_timeouts(xprt, sock);
2257 
2258 		write_lock_bh(&sk->sk_callback_lock);
2259 
2260 		xs_save_old_callbacks(transport, sk);
2261 
2262 		sk->sk_user_data = xprt;
2263 		sk->sk_data_ready = xs_data_ready;
2264 		sk->sk_state_change = xs_tcp_state_change;
2265 		sk->sk_write_space = xs_tcp_write_space;
2266 		sock_set_flag(sk, SOCK_FASYNC);
2267 		sk->sk_error_report = xs_error_report;
2268 
2269 		/* socket options */
2270 		sock_reset_flag(sk, SOCK_LINGER);
2271 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2272 
2273 		xprt_clear_connected(xprt);
2274 
2275 		/* Reset to new socket */
2276 		transport->sock = sock;
2277 		transport->inet = sk;
2278 
2279 		write_unlock_bh(&sk->sk_callback_lock);
2280 	}
2281 
2282 	if (!xprt_bound(xprt))
2283 		goto out;
2284 
2285 	xs_set_memalloc(xprt);
2286 
2287 	xs_stream_start_connect(transport);
2288 
2289 	/* Tell the socket layer to start connecting... */
2290 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2291 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2292 	switch (ret) {
2293 	case 0:
2294 		xs_set_srcport(transport, sock);
2295 		/* fall through */
2296 	case -EINPROGRESS:
2297 		/* SYN_SENT! */
2298 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2299 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2300 		break;
2301 	case -EADDRNOTAVAIL:
2302 		/* Source port number is unavailable. Try a new one! */
2303 		transport->srcport = 0;
2304 	}
2305 out:
2306 	return ret;
2307 }
2308 
2309 /**
2310  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2311  * @work: queued work item
2312  *
2313  * Invoked by a work queue tasklet.
2314  */
2315 static void xs_tcp_setup_socket(struct work_struct *work)
2316 {
2317 	struct sock_xprt *transport =
2318 		container_of(work, struct sock_xprt, connect_worker.work);
2319 	struct socket *sock = transport->sock;
2320 	struct rpc_xprt *xprt = &transport->xprt;
2321 	int status = -EIO;
2322 
2323 	if (!sock) {
2324 		sock = xs_create_sock(xprt, transport,
2325 				xs_addr(xprt)->sa_family, SOCK_STREAM,
2326 				IPPROTO_TCP, true);
2327 		if (IS_ERR(sock)) {
2328 			status = PTR_ERR(sock);
2329 			goto out;
2330 		}
2331 	}
2332 
2333 	dprintk("RPC:       worker connecting xprt %p via %s to "
2334 				"%s (port %s)\n", xprt,
2335 			xprt->address_strings[RPC_DISPLAY_PROTO],
2336 			xprt->address_strings[RPC_DISPLAY_ADDR],
2337 			xprt->address_strings[RPC_DISPLAY_PORT]);
2338 
2339 	status = xs_tcp_finish_connecting(xprt, sock);
2340 	trace_rpc_socket_connect(xprt, sock, status);
2341 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2342 			xprt, -status, xprt_connected(xprt),
2343 			sock->sk->sk_state);
2344 	switch (status) {
2345 	default:
2346 		printk("%s: connect returned unhandled error %d\n",
2347 			__func__, status);
2348 		/* fall through */
2349 	case -EADDRNOTAVAIL:
2350 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2351 		 * and retry
2352 		 */
2353 		xs_tcp_force_close(xprt);
2354 		break;
2355 	case 0:
2356 	case -EINPROGRESS:
2357 	case -EALREADY:
2358 		xprt_unlock_connect(xprt, transport);
2359 		return;
2360 	case -EINVAL:
2361 		/* Happens, for instance, if the user specified a link
2362 		 * local IPv6 address without a scope-id.
2363 		 */
2364 	case -ECONNREFUSED:
2365 	case -ECONNRESET:
2366 	case -ENETDOWN:
2367 	case -ENETUNREACH:
2368 	case -EHOSTUNREACH:
2369 	case -EADDRINUSE:
2370 	case -ENOBUFS:
2371 		/*
2372 		 * xs_tcp_force_close() wakes tasks with -EIO.
2373 		 * We need to wake them first to ensure the
2374 		 * correct error code.
2375 		 */
2376 		xprt_wake_pending_tasks(xprt, status);
2377 		xs_tcp_force_close(xprt);
2378 		goto out;
2379 	}
2380 	status = -EAGAIN;
2381 out:
2382 	xprt_clear_connecting(xprt);
2383 	xprt_unlock_connect(xprt, transport);
2384 	xprt_wake_pending_tasks(xprt, status);
2385 }
2386 
2387 static unsigned long xs_reconnect_delay(const struct rpc_xprt *xprt)
2388 {
2389 	unsigned long start, now = jiffies;
2390 
2391 	start = xprt->stat.connect_start + xprt->reestablish_timeout;
2392 	if (time_after(start, now))
2393 		return start - now;
2394 	return 0;
2395 }
2396 
2397 static void xs_reconnect_backoff(struct rpc_xprt *xprt)
2398 {
2399 	xprt->reestablish_timeout <<= 1;
2400 	if (xprt->reestablish_timeout > xprt->max_reconnect_timeout)
2401 		xprt->reestablish_timeout = xprt->max_reconnect_timeout;
2402 	if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2403 		xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2404 }
2405 
2406 /**
2407  * xs_connect - connect a socket to a remote endpoint
2408  * @xprt: pointer to transport structure
2409  * @task: address of RPC task that manages state of connect request
2410  *
2411  * TCP: If the remote end dropped the connection, delay reconnecting.
2412  *
2413  * UDP socket connects are synchronous, but we use a work queue anyway
2414  * to guarantee that even unprivileged user processes can set up a
2415  * socket on a privileged port.
2416  *
2417  * If a UDP socket connect fails, the delay behavior here prevents
2418  * retry floods (hard mounts).
2419  */
2420 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2421 {
2422 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2423 	unsigned long delay = 0;
2424 
2425 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2426 
2427 	if (transport->sock != NULL) {
2428 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2429 				"seconds\n",
2430 				xprt, xprt->reestablish_timeout / HZ);
2431 
2432 		/* Start by resetting any existing state */
2433 		xs_reset_transport(transport);
2434 
2435 		delay = xs_reconnect_delay(xprt);
2436 		xs_reconnect_backoff(xprt);
2437 
2438 	} else
2439 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2440 
2441 	queue_delayed_work(xprtiod_workqueue,
2442 			&transport->connect_worker,
2443 			delay);
2444 }
2445 
2446 /**
2447  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2448  * @xprt: rpc_xprt struct containing statistics
2449  * @seq: output file
2450  *
2451  */
2452 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2453 {
2454 	long idle_time = 0;
2455 
2456 	if (xprt_connected(xprt))
2457 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2458 
2459 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2460 			"%llu %llu %lu %llu %llu\n",
2461 			xprt->stat.bind_count,
2462 			xprt->stat.connect_count,
2463 			xprt->stat.connect_time / HZ,
2464 			idle_time,
2465 			xprt->stat.sends,
2466 			xprt->stat.recvs,
2467 			xprt->stat.bad_xids,
2468 			xprt->stat.req_u,
2469 			xprt->stat.bklog_u,
2470 			xprt->stat.max_slots,
2471 			xprt->stat.sending_u,
2472 			xprt->stat.pending_u);
2473 }
2474 
2475 /**
2476  * xs_udp_print_stats - display UDP socket-specifc stats
2477  * @xprt: rpc_xprt struct containing statistics
2478  * @seq: output file
2479  *
2480  */
2481 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2482 {
2483 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2484 
2485 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2486 			"%lu %llu %llu\n",
2487 			transport->srcport,
2488 			xprt->stat.bind_count,
2489 			xprt->stat.sends,
2490 			xprt->stat.recvs,
2491 			xprt->stat.bad_xids,
2492 			xprt->stat.req_u,
2493 			xprt->stat.bklog_u,
2494 			xprt->stat.max_slots,
2495 			xprt->stat.sending_u,
2496 			xprt->stat.pending_u);
2497 }
2498 
2499 /**
2500  * xs_tcp_print_stats - display TCP socket-specifc stats
2501  * @xprt: rpc_xprt struct containing statistics
2502  * @seq: output file
2503  *
2504  */
2505 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2506 {
2507 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2508 	long idle_time = 0;
2509 
2510 	if (xprt_connected(xprt))
2511 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2512 
2513 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2514 			"%llu %llu %lu %llu %llu\n",
2515 			transport->srcport,
2516 			xprt->stat.bind_count,
2517 			xprt->stat.connect_count,
2518 			xprt->stat.connect_time / HZ,
2519 			idle_time,
2520 			xprt->stat.sends,
2521 			xprt->stat.recvs,
2522 			xprt->stat.bad_xids,
2523 			xprt->stat.req_u,
2524 			xprt->stat.bklog_u,
2525 			xprt->stat.max_slots,
2526 			xprt->stat.sending_u,
2527 			xprt->stat.pending_u);
2528 }
2529 
2530 /*
2531  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2532  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2533  * to use the server side send routines.
2534  */
2535 static int bc_malloc(struct rpc_task *task)
2536 {
2537 	struct rpc_rqst *rqst = task->tk_rqstp;
2538 	size_t size = rqst->rq_callsize;
2539 	struct page *page;
2540 	struct rpc_buffer *buf;
2541 
2542 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2543 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2544 			  size);
2545 		return -EINVAL;
2546 	}
2547 
2548 	page = alloc_page(GFP_KERNEL);
2549 	if (!page)
2550 		return -ENOMEM;
2551 
2552 	buf = page_address(page);
2553 	buf->len = PAGE_SIZE;
2554 
2555 	rqst->rq_buffer = buf->data;
2556 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2557 	return 0;
2558 }
2559 
2560 /*
2561  * Free the space allocated in the bc_alloc routine
2562  */
2563 static void bc_free(struct rpc_task *task)
2564 {
2565 	void *buffer = task->tk_rqstp->rq_buffer;
2566 	struct rpc_buffer *buf;
2567 
2568 	buf = container_of(buffer, struct rpc_buffer, data);
2569 	free_page((unsigned long)buf);
2570 }
2571 
2572 /*
2573  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2574  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2575  */
2576 static int bc_sendto(struct rpc_rqst *req)
2577 {
2578 	int len;
2579 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2580 	struct sock_xprt *transport =
2581 			container_of(req->rq_xprt, struct sock_xprt, xprt);
2582 	unsigned long headoff;
2583 	unsigned long tailoff;
2584 	struct page *tailpage;
2585 	struct msghdr msg = {
2586 		.msg_flags	= MSG_MORE
2587 	};
2588 	rpc_fraghdr marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT |
2589 					 (u32)xbufp->len);
2590 	struct kvec iov = {
2591 		.iov_base	= &marker,
2592 		.iov_len	= sizeof(marker),
2593 	};
2594 
2595 	len = kernel_sendmsg(transport->sock, &msg, &iov, 1, iov.iov_len);
2596 	if (len != iov.iov_len)
2597 		return -EAGAIN;
2598 
2599 	tailpage = NULL;
2600 	if (xbufp->tail[0].iov_len)
2601 		tailpage = virt_to_page(xbufp->tail[0].iov_base);
2602 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2603 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2604 	len = svc_send_common(transport->sock, xbufp,
2605 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2606 			      tailpage, tailoff);
2607 	if (len != xbufp->len)
2608 		return -EAGAIN;
2609 	return len;
2610 }
2611 
2612 /*
2613  * The send routine. Borrows from svc_send
2614  */
2615 static int bc_send_request(struct rpc_rqst *req)
2616 {
2617 	struct svc_xprt	*xprt;
2618 	int len;
2619 
2620 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2621 	/*
2622 	 * Get the server socket associated with this callback xprt
2623 	 */
2624 	xprt = req->rq_xprt->bc_xprt;
2625 
2626 	/*
2627 	 * Grab the mutex to serialize data as the connection is shared
2628 	 * with the fore channel
2629 	 */
2630 	mutex_lock(&xprt->xpt_mutex);
2631 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2632 		len = -ENOTCONN;
2633 	else
2634 		len = bc_sendto(req);
2635 	mutex_unlock(&xprt->xpt_mutex);
2636 
2637 	if (len > 0)
2638 		len = 0;
2639 
2640 	return len;
2641 }
2642 
2643 /*
2644  * The close routine. Since this is client initiated, we do nothing
2645  */
2646 
2647 static void bc_close(struct rpc_xprt *xprt)
2648 {
2649 }
2650 
2651 /*
2652  * The xprt destroy routine. Again, because this connection is client
2653  * initiated, we do nothing
2654  */
2655 
2656 static void bc_destroy(struct rpc_xprt *xprt)
2657 {
2658 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2659 
2660 	xs_xprt_free(xprt);
2661 	module_put(THIS_MODULE);
2662 }
2663 
2664 static const struct rpc_xprt_ops xs_local_ops = {
2665 	.reserve_xprt		= xprt_reserve_xprt,
2666 	.release_xprt		= xprt_release_xprt,
2667 	.alloc_slot		= xprt_alloc_slot,
2668 	.free_slot		= xprt_free_slot,
2669 	.rpcbind		= xs_local_rpcbind,
2670 	.set_port		= xs_local_set_port,
2671 	.connect		= xs_local_connect,
2672 	.buf_alloc		= rpc_malloc,
2673 	.buf_free		= rpc_free,
2674 	.prepare_request	= xs_stream_prepare_request,
2675 	.send_request		= xs_local_send_request,
2676 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2677 	.close			= xs_close,
2678 	.destroy		= xs_destroy,
2679 	.print_stats		= xs_local_print_stats,
2680 	.enable_swap		= xs_enable_swap,
2681 	.disable_swap		= xs_disable_swap,
2682 };
2683 
2684 static const struct rpc_xprt_ops xs_udp_ops = {
2685 	.set_buffer_size	= xs_udp_set_buffer_size,
2686 	.reserve_xprt		= xprt_reserve_xprt_cong,
2687 	.release_xprt		= xprt_release_xprt_cong,
2688 	.alloc_slot		= xprt_alloc_slot,
2689 	.free_slot		= xprt_free_slot,
2690 	.rpcbind		= rpcb_getport_async,
2691 	.set_port		= xs_set_port,
2692 	.connect		= xs_connect,
2693 	.buf_alloc		= rpc_malloc,
2694 	.buf_free		= rpc_free,
2695 	.send_request		= xs_udp_send_request,
2696 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2697 	.timer			= xs_udp_timer,
2698 	.release_request	= xprt_release_rqst_cong,
2699 	.close			= xs_close,
2700 	.destroy		= xs_destroy,
2701 	.print_stats		= xs_udp_print_stats,
2702 	.enable_swap		= xs_enable_swap,
2703 	.disable_swap		= xs_disable_swap,
2704 	.inject_disconnect	= xs_inject_disconnect,
2705 };
2706 
2707 static const struct rpc_xprt_ops xs_tcp_ops = {
2708 	.reserve_xprt		= xprt_reserve_xprt,
2709 	.release_xprt		= xprt_release_xprt,
2710 	.alloc_slot		= xprt_alloc_slot,
2711 	.free_slot		= xprt_free_slot,
2712 	.rpcbind		= rpcb_getport_async,
2713 	.set_port		= xs_set_port,
2714 	.connect		= xs_connect,
2715 	.buf_alloc		= rpc_malloc,
2716 	.buf_free		= rpc_free,
2717 	.prepare_request	= xs_stream_prepare_request,
2718 	.send_request		= xs_tcp_send_request,
2719 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2720 	.close			= xs_tcp_shutdown,
2721 	.destroy		= xs_destroy,
2722 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2723 	.print_stats		= xs_tcp_print_stats,
2724 	.enable_swap		= xs_enable_swap,
2725 	.disable_swap		= xs_disable_swap,
2726 	.inject_disconnect	= xs_inject_disconnect,
2727 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2728 	.bc_setup		= xprt_setup_bc,
2729 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2730 	.bc_free_rqst		= xprt_free_bc_rqst,
2731 	.bc_destroy		= xprt_destroy_bc,
2732 #endif
2733 };
2734 
2735 /*
2736  * The rpc_xprt_ops for the server backchannel
2737  */
2738 
2739 static const struct rpc_xprt_ops bc_tcp_ops = {
2740 	.reserve_xprt		= xprt_reserve_xprt,
2741 	.release_xprt		= xprt_release_xprt,
2742 	.alloc_slot		= xprt_alloc_slot,
2743 	.free_slot		= xprt_free_slot,
2744 	.buf_alloc		= bc_malloc,
2745 	.buf_free		= bc_free,
2746 	.send_request		= bc_send_request,
2747 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2748 	.close			= bc_close,
2749 	.destroy		= bc_destroy,
2750 	.print_stats		= xs_tcp_print_stats,
2751 	.enable_swap		= xs_enable_swap,
2752 	.disable_swap		= xs_disable_swap,
2753 	.inject_disconnect	= xs_inject_disconnect,
2754 };
2755 
2756 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2757 {
2758 	static const struct sockaddr_in sin = {
2759 		.sin_family		= AF_INET,
2760 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2761 	};
2762 	static const struct sockaddr_in6 sin6 = {
2763 		.sin6_family		= AF_INET6,
2764 		.sin6_addr		= IN6ADDR_ANY_INIT,
2765 	};
2766 
2767 	switch (family) {
2768 	case AF_LOCAL:
2769 		break;
2770 	case AF_INET:
2771 		memcpy(sap, &sin, sizeof(sin));
2772 		break;
2773 	case AF_INET6:
2774 		memcpy(sap, &sin6, sizeof(sin6));
2775 		break;
2776 	default:
2777 		dprintk("RPC:       %s: Bad address family\n", __func__);
2778 		return -EAFNOSUPPORT;
2779 	}
2780 	return 0;
2781 }
2782 
2783 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2784 				      unsigned int slot_table_size,
2785 				      unsigned int max_slot_table_size)
2786 {
2787 	struct rpc_xprt *xprt;
2788 	struct sock_xprt *new;
2789 
2790 	if (args->addrlen > sizeof(xprt->addr)) {
2791 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2792 		return ERR_PTR(-EBADF);
2793 	}
2794 
2795 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2796 			max_slot_table_size);
2797 	if (xprt == NULL) {
2798 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2799 				"rpc_xprt\n");
2800 		return ERR_PTR(-ENOMEM);
2801 	}
2802 
2803 	new = container_of(xprt, struct sock_xprt, xprt);
2804 	mutex_init(&new->recv_mutex);
2805 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2806 	xprt->addrlen = args->addrlen;
2807 	if (args->srcaddr)
2808 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2809 	else {
2810 		int err;
2811 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2812 					(struct sockaddr *)&new->srcaddr);
2813 		if (err != 0) {
2814 			xprt_free(xprt);
2815 			return ERR_PTR(err);
2816 		}
2817 	}
2818 
2819 	return xprt;
2820 }
2821 
2822 static const struct rpc_timeout xs_local_default_timeout = {
2823 	.to_initval = 10 * HZ,
2824 	.to_maxval = 10 * HZ,
2825 	.to_retries = 2,
2826 };
2827 
2828 /**
2829  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2830  * @args: rpc transport creation arguments
2831  *
2832  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2833  */
2834 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2835 {
2836 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2837 	struct sock_xprt *transport;
2838 	struct rpc_xprt *xprt;
2839 	struct rpc_xprt *ret;
2840 
2841 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2842 			xprt_max_tcp_slot_table_entries);
2843 	if (IS_ERR(xprt))
2844 		return xprt;
2845 	transport = container_of(xprt, struct sock_xprt, xprt);
2846 
2847 	xprt->prot = 0;
2848 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2849 
2850 	xprt->bind_timeout = XS_BIND_TO;
2851 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2852 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2853 
2854 	xprt->ops = &xs_local_ops;
2855 	xprt->timeout = &xs_local_default_timeout;
2856 
2857 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
2858 	INIT_DELAYED_WORK(&transport->connect_worker, xs_dummy_setup_socket);
2859 
2860 	switch (sun->sun_family) {
2861 	case AF_LOCAL:
2862 		if (sun->sun_path[0] != '/') {
2863 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2864 					sun->sun_path);
2865 			ret = ERR_PTR(-EINVAL);
2866 			goto out_err;
2867 		}
2868 		xprt_set_bound(xprt);
2869 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2870 		ret = ERR_PTR(xs_local_setup_socket(transport));
2871 		if (ret)
2872 			goto out_err;
2873 		break;
2874 	default:
2875 		ret = ERR_PTR(-EAFNOSUPPORT);
2876 		goto out_err;
2877 	}
2878 
2879 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2880 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2881 
2882 	if (try_module_get(THIS_MODULE))
2883 		return xprt;
2884 	ret = ERR_PTR(-EINVAL);
2885 out_err:
2886 	xs_xprt_free(xprt);
2887 	return ret;
2888 }
2889 
2890 static const struct rpc_timeout xs_udp_default_timeout = {
2891 	.to_initval = 5 * HZ,
2892 	.to_maxval = 30 * HZ,
2893 	.to_increment = 5 * HZ,
2894 	.to_retries = 5,
2895 };
2896 
2897 /**
2898  * xs_setup_udp - Set up transport to use a UDP socket
2899  * @args: rpc transport creation arguments
2900  *
2901  */
2902 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2903 {
2904 	struct sockaddr *addr = args->dstaddr;
2905 	struct rpc_xprt *xprt;
2906 	struct sock_xprt *transport;
2907 	struct rpc_xprt *ret;
2908 
2909 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2910 			xprt_udp_slot_table_entries);
2911 	if (IS_ERR(xprt))
2912 		return xprt;
2913 	transport = container_of(xprt, struct sock_xprt, xprt);
2914 
2915 	xprt->prot = IPPROTO_UDP;
2916 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2917 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2918 
2919 	xprt->bind_timeout = XS_BIND_TO;
2920 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2921 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2922 
2923 	xprt->ops = &xs_udp_ops;
2924 
2925 	xprt->timeout = &xs_udp_default_timeout;
2926 
2927 	INIT_WORK(&transport->recv_worker, xs_udp_data_receive_workfn);
2928 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
2929 
2930 	switch (addr->sa_family) {
2931 	case AF_INET:
2932 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2933 			xprt_set_bound(xprt);
2934 
2935 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2936 		break;
2937 	case AF_INET6:
2938 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2939 			xprt_set_bound(xprt);
2940 
2941 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2942 		break;
2943 	default:
2944 		ret = ERR_PTR(-EAFNOSUPPORT);
2945 		goto out_err;
2946 	}
2947 
2948 	if (xprt_bound(xprt))
2949 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2950 				xprt->address_strings[RPC_DISPLAY_ADDR],
2951 				xprt->address_strings[RPC_DISPLAY_PORT],
2952 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2953 	else
2954 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2955 				xprt->address_strings[RPC_DISPLAY_ADDR],
2956 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2957 
2958 	if (try_module_get(THIS_MODULE))
2959 		return xprt;
2960 	ret = ERR_PTR(-EINVAL);
2961 out_err:
2962 	xs_xprt_free(xprt);
2963 	return ret;
2964 }
2965 
2966 static const struct rpc_timeout xs_tcp_default_timeout = {
2967 	.to_initval = 60 * HZ,
2968 	.to_maxval = 60 * HZ,
2969 	.to_retries = 2,
2970 };
2971 
2972 /**
2973  * xs_setup_tcp - Set up transport to use a TCP socket
2974  * @args: rpc transport creation arguments
2975  *
2976  */
2977 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2978 {
2979 	struct sockaddr *addr = args->dstaddr;
2980 	struct rpc_xprt *xprt;
2981 	struct sock_xprt *transport;
2982 	struct rpc_xprt *ret;
2983 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
2984 
2985 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
2986 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
2987 
2988 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2989 			max_slot_table_size);
2990 	if (IS_ERR(xprt))
2991 		return xprt;
2992 	transport = container_of(xprt, struct sock_xprt, xprt);
2993 
2994 	xprt->prot = IPPROTO_TCP;
2995 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2996 
2997 	xprt->bind_timeout = XS_BIND_TO;
2998 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2999 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3000 
3001 	xprt->ops = &xs_tcp_ops;
3002 	xprt->timeout = &xs_tcp_default_timeout;
3003 
3004 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3005 	xprt->connect_timeout = xprt->timeout->to_initval *
3006 		(xprt->timeout->to_retries + 1);
3007 
3008 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
3009 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3010 
3011 	switch (addr->sa_family) {
3012 	case AF_INET:
3013 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3014 			xprt_set_bound(xprt);
3015 
3016 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3017 		break;
3018 	case AF_INET6:
3019 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3020 			xprt_set_bound(xprt);
3021 
3022 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3023 		break;
3024 	default:
3025 		ret = ERR_PTR(-EAFNOSUPPORT);
3026 		goto out_err;
3027 	}
3028 
3029 	if (xprt_bound(xprt))
3030 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3031 				xprt->address_strings[RPC_DISPLAY_ADDR],
3032 				xprt->address_strings[RPC_DISPLAY_PORT],
3033 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3034 	else
3035 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3036 				xprt->address_strings[RPC_DISPLAY_ADDR],
3037 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3038 
3039 	if (try_module_get(THIS_MODULE))
3040 		return xprt;
3041 	ret = ERR_PTR(-EINVAL);
3042 out_err:
3043 	xs_xprt_free(xprt);
3044 	return ret;
3045 }
3046 
3047 /**
3048  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3049  * @args: rpc transport creation arguments
3050  *
3051  */
3052 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3053 {
3054 	struct sockaddr *addr = args->dstaddr;
3055 	struct rpc_xprt *xprt;
3056 	struct sock_xprt *transport;
3057 	struct svc_sock *bc_sock;
3058 	struct rpc_xprt *ret;
3059 
3060 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3061 			xprt_tcp_slot_table_entries);
3062 	if (IS_ERR(xprt))
3063 		return xprt;
3064 	transport = container_of(xprt, struct sock_xprt, xprt);
3065 
3066 	xprt->prot = IPPROTO_TCP;
3067 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3068 	xprt->timeout = &xs_tcp_default_timeout;
3069 
3070 	/* backchannel */
3071 	xprt_set_bound(xprt);
3072 	xprt->bind_timeout = 0;
3073 	xprt->reestablish_timeout = 0;
3074 	xprt->idle_timeout = 0;
3075 
3076 	xprt->ops = &bc_tcp_ops;
3077 
3078 	switch (addr->sa_family) {
3079 	case AF_INET:
3080 		xs_format_peer_addresses(xprt, "tcp",
3081 					 RPCBIND_NETID_TCP);
3082 		break;
3083 	case AF_INET6:
3084 		xs_format_peer_addresses(xprt, "tcp",
3085 				   RPCBIND_NETID_TCP6);
3086 		break;
3087 	default:
3088 		ret = ERR_PTR(-EAFNOSUPPORT);
3089 		goto out_err;
3090 	}
3091 
3092 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3093 			xprt->address_strings[RPC_DISPLAY_ADDR],
3094 			xprt->address_strings[RPC_DISPLAY_PORT],
3095 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3096 
3097 	/*
3098 	 * Once we've associated a backchannel xprt with a connection,
3099 	 * we want to keep it around as long as the connection lasts,
3100 	 * in case we need to start using it for a backchannel again;
3101 	 * this reference won't be dropped until bc_xprt is destroyed.
3102 	 */
3103 	xprt_get(xprt);
3104 	args->bc_xprt->xpt_bc_xprt = xprt;
3105 	xprt->bc_xprt = args->bc_xprt;
3106 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3107 	transport->sock = bc_sock->sk_sock;
3108 	transport->inet = bc_sock->sk_sk;
3109 
3110 	/*
3111 	 * Since we don't want connections for the backchannel, we set
3112 	 * the xprt status to connected
3113 	 */
3114 	xprt_set_connected(xprt);
3115 
3116 	if (try_module_get(THIS_MODULE))
3117 		return xprt;
3118 
3119 	args->bc_xprt->xpt_bc_xprt = NULL;
3120 	args->bc_xprt->xpt_bc_xps = NULL;
3121 	xprt_put(xprt);
3122 	ret = ERR_PTR(-EINVAL);
3123 out_err:
3124 	xs_xprt_free(xprt);
3125 	return ret;
3126 }
3127 
3128 static struct xprt_class	xs_local_transport = {
3129 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3130 	.name		= "named UNIX socket",
3131 	.owner		= THIS_MODULE,
3132 	.ident		= XPRT_TRANSPORT_LOCAL,
3133 	.setup		= xs_setup_local,
3134 };
3135 
3136 static struct xprt_class	xs_udp_transport = {
3137 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3138 	.name		= "udp",
3139 	.owner		= THIS_MODULE,
3140 	.ident		= XPRT_TRANSPORT_UDP,
3141 	.setup		= xs_setup_udp,
3142 };
3143 
3144 static struct xprt_class	xs_tcp_transport = {
3145 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3146 	.name		= "tcp",
3147 	.owner		= THIS_MODULE,
3148 	.ident		= XPRT_TRANSPORT_TCP,
3149 	.setup		= xs_setup_tcp,
3150 };
3151 
3152 static struct xprt_class	xs_bc_tcp_transport = {
3153 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3154 	.name		= "tcp NFSv4.1 backchannel",
3155 	.owner		= THIS_MODULE,
3156 	.ident		= XPRT_TRANSPORT_BC_TCP,
3157 	.setup		= xs_setup_bc_tcp,
3158 };
3159 
3160 /**
3161  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3162  *
3163  */
3164 int init_socket_xprt(void)
3165 {
3166 	if (!sunrpc_table_header)
3167 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
3168 
3169 	xprt_register_transport(&xs_local_transport);
3170 	xprt_register_transport(&xs_udp_transport);
3171 	xprt_register_transport(&xs_tcp_transport);
3172 	xprt_register_transport(&xs_bc_tcp_transport);
3173 
3174 	return 0;
3175 }
3176 
3177 /**
3178  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3179  *
3180  */
3181 void cleanup_socket_xprt(void)
3182 {
3183 	if (sunrpc_table_header) {
3184 		unregister_sysctl_table(sunrpc_table_header);
3185 		sunrpc_table_header = NULL;
3186 	}
3187 
3188 	xprt_unregister_transport(&xs_local_transport);
3189 	xprt_unregister_transport(&xs_udp_transport);
3190 	xprt_unregister_transport(&xs_tcp_transport);
3191 	xprt_unregister_transport(&xs_bc_tcp_transport);
3192 }
3193 
3194 static int param_set_uint_minmax(const char *val,
3195 		const struct kernel_param *kp,
3196 		unsigned int min, unsigned int max)
3197 {
3198 	unsigned int num;
3199 	int ret;
3200 
3201 	if (!val)
3202 		return -EINVAL;
3203 	ret = kstrtouint(val, 0, &num);
3204 	if (ret)
3205 		return ret;
3206 	if (num < min || num > max)
3207 		return -EINVAL;
3208 	*((unsigned int *)kp->arg) = num;
3209 	return 0;
3210 }
3211 
3212 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3213 {
3214 	return param_set_uint_minmax(val, kp,
3215 			RPC_MIN_RESVPORT,
3216 			RPC_MAX_RESVPORT);
3217 }
3218 
3219 static const struct kernel_param_ops param_ops_portnr = {
3220 	.set = param_set_portnr,
3221 	.get = param_get_uint,
3222 };
3223 
3224 #define param_check_portnr(name, p) \
3225 	__param_check(name, p, unsigned int);
3226 
3227 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3228 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3229 
3230 static int param_set_slot_table_size(const char *val,
3231 				     const struct kernel_param *kp)
3232 {
3233 	return param_set_uint_minmax(val, kp,
3234 			RPC_MIN_SLOT_TABLE,
3235 			RPC_MAX_SLOT_TABLE);
3236 }
3237 
3238 static const struct kernel_param_ops param_ops_slot_table_size = {
3239 	.set = param_set_slot_table_size,
3240 	.get = param_get_uint,
3241 };
3242 
3243 #define param_check_slot_table_size(name, p) \
3244 	__param_check(name, p, unsigned int);
3245 
3246 static int param_set_max_slot_table_size(const char *val,
3247 				     const struct kernel_param *kp)
3248 {
3249 	return param_set_uint_minmax(val, kp,
3250 			RPC_MIN_SLOT_TABLE,
3251 			RPC_MAX_SLOT_TABLE_LIMIT);
3252 }
3253 
3254 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3255 	.set = param_set_max_slot_table_size,
3256 	.get = param_get_uint,
3257 };
3258 
3259 #define param_check_max_slot_table_size(name, p) \
3260 	__param_check(name, p, unsigned int);
3261 
3262 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3263 		   slot_table_size, 0644);
3264 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3265 		   max_slot_table_size, 0644);
3266 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3267 		   slot_table_size, 0644);
3268