xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision 6562c9ac)
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 "socklib.h"
58 #include "sunrpc.h"
59 
60 static void xs_close(struct rpc_xprt *xprt);
61 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock);
62 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
63 		struct socket *sock);
64 
65 /*
66  * xprtsock tunables
67  */
68 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
69 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
70 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
71 
72 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
73 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
74 
75 #define XS_TCP_LINGER_TO	(15U * HZ)
76 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
77 
78 /*
79  * We can register our own files under /proc/sys/sunrpc by
80  * calling register_sysctl_table() again.  The files in that
81  * directory become the union of all files registered there.
82  *
83  * We simply need to make sure that we don't collide with
84  * someone else's file names!
85  */
86 
87 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
88 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
89 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
90 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
91 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
92 
93 static struct ctl_table_header *sunrpc_table_header;
94 
95 static struct xprt_class xs_local_transport;
96 static struct xprt_class xs_udp_transport;
97 static struct xprt_class xs_tcp_transport;
98 static struct xprt_class xs_bc_tcp_transport;
99 
100 /*
101  * FIXME: changing the UDP slot table size should also resize the UDP
102  *        socket buffers for existing UDP transports
103  */
104 static struct ctl_table xs_tunables_table[] = {
105 	{
106 		.procname	= "udp_slot_table_entries",
107 		.data		= &xprt_udp_slot_table_entries,
108 		.maxlen		= sizeof(unsigned int),
109 		.mode		= 0644,
110 		.proc_handler	= proc_dointvec_minmax,
111 		.extra1		= &min_slot_table_size,
112 		.extra2		= &max_slot_table_size
113 	},
114 	{
115 		.procname	= "tcp_slot_table_entries",
116 		.data		= &xprt_tcp_slot_table_entries,
117 		.maxlen		= sizeof(unsigned int),
118 		.mode		= 0644,
119 		.proc_handler	= proc_dointvec_minmax,
120 		.extra1		= &min_slot_table_size,
121 		.extra2		= &max_slot_table_size
122 	},
123 	{
124 		.procname	= "tcp_max_slot_table_entries",
125 		.data		= &xprt_max_tcp_slot_table_entries,
126 		.maxlen		= sizeof(unsigned int),
127 		.mode		= 0644,
128 		.proc_handler	= proc_dointvec_minmax,
129 		.extra1		= &min_slot_table_size,
130 		.extra2		= &max_tcp_slot_table_limit
131 	},
132 	{
133 		.procname	= "min_resvport",
134 		.data		= &xprt_min_resvport,
135 		.maxlen		= sizeof(unsigned int),
136 		.mode		= 0644,
137 		.proc_handler	= proc_dointvec_minmax,
138 		.extra1		= &xprt_min_resvport_limit,
139 		.extra2		= &xprt_max_resvport_limit
140 	},
141 	{
142 		.procname	= "max_resvport",
143 		.data		= &xprt_max_resvport,
144 		.maxlen		= sizeof(unsigned int),
145 		.mode		= 0644,
146 		.proc_handler	= proc_dointvec_minmax,
147 		.extra1		= &xprt_min_resvport_limit,
148 		.extra2		= &xprt_max_resvport_limit
149 	},
150 	{
151 		.procname	= "tcp_fin_timeout",
152 		.data		= &xs_tcp_fin_timeout,
153 		.maxlen		= sizeof(xs_tcp_fin_timeout),
154 		.mode		= 0644,
155 		.proc_handler	= proc_dointvec_jiffies,
156 	},
157 	{ },
158 };
159 
160 static struct ctl_table sunrpc_table[] = {
161 	{
162 		.procname	= "sunrpc",
163 		.mode		= 0555,
164 		.child		= xs_tunables_table
165 	},
166 	{ },
167 };
168 
169 /*
170  * Wait duration for a reply from the RPC portmapper.
171  */
172 #define XS_BIND_TO		(60U * HZ)
173 
174 /*
175  * Delay if a UDP socket connect error occurs.  This is most likely some
176  * kind of resource problem on the local host.
177  */
178 #define XS_UDP_REEST_TO		(2U * HZ)
179 
180 /*
181  * The reestablish timeout allows clients to delay for a bit before attempting
182  * to reconnect to a server that just dropped our connection.
183  *
184  * We implement an exponential backoff when trying to reestablish a TCP
185  * transport connection with the server.  Some servers like to drop a TCP
186  * connection when they are overworked, so we start with a short timeout and
187  * increase over time if the server is down or not responding.
188  */
189 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
190 
191 /*
192  * TCP idle timeout; client drops the transport socket if it is idle
193  * for this long.  Note that we also timeout UDP sockets to prevent
194  * holding port numbers when there is no RPC traffic.
195  */
196 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
197 
198 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
199 # undef  RPC_DEBUG_DATA
200 # define RPCDBG_FACILITY	RPCDBG_TRANS
201 #endif
202 
203 #ifdef RPC_DEBUG_DATA
204 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
205 {
206 	u8 *buf = (u8 *) packet;
207 	int j;
208 
209 	dprintk("RPC:       %s\n", msg);
210 	for (j = 0; j < count && j < 128; j += 4) {
211 		if (!(j & 31)) {
212 			if (j)
213 				dprintk("\n");
214 			dprintk("0x%04x ", j);
215 		}
216 		dprintk("%02x%02x%02x%02x ",
217 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
218 	}
219 	dprintk("\n");
220 }
221 #else
222 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
223 {
224 	/* NOP */
225 }
226 #endif
227 
228 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
229 {
230 	return (struct rpc_xprt *) sk->sk_user_data;
231 }
232 
233 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
234 {
235 	return (struct sockaddr *) &xprt->addr;
236 }
237 
238 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
239 {
240 	return (struct sockaddr_un *) &xprt->addr;
241 }
242 
243 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
244 {
245 	return (struct sockaddr_in *) &xprt->addr;
246 }
247 
248 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
249 {
250 	return (struct sockaddr_in6 *) &xprt->addr;
251 }
252 
253 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
254 {
255 	struct sockaddr *sap = xs_addr(xprt);
256 	struct sockaddr_in6 *sin6;
257 	struct sockaddr_in *sin;
258 	struct sockaddr_un *sun;
259 	char buf[128];
260 
261 	switch (sap->sa_family) {
262 	case AF_LOCAL:
263 		sun = xs_addr_un(xprt);
264 		strlcpy(buf, sun->sun_path, sizeof(buf));
265 		xprt->address_strings[RPC_DISPLAY_ADDR] =
266 						kstrdup(buf, GFP_KERNEL);
267 		break;
268 	case AF_INET:
269 		(void)rpc_ntop(sap, buf, sizeof(buf));
270 		xprt->address_strings[RPC_DISPLAY_ADDR] =
271 						kstrdup(buf, GFP_KERNEL);
272 		sin = xs_addr_in(xprt);
273 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
274 		break;
275 	case AF_INET6:
276 		(void)rpc_ntop(sap, buf, sizeof(buf));
277 		xprt->address_strings[RPC_DISPLAY_ADDR] =
278 						kstrdup(buf, GFP_KERNEL);
279 		sin6 = xs_addr_in6(xprt);
280 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
281 		break;
282 	default:
283 		BUG();
284 	}
285 
286 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
287 }
288 
289 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
290 {
291 	struct sockaddr *sap = xs_addr(xprt);
292 	char buf[128];
293 
294 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
295 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
296 
297 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
298 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
299 }
300 
301 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
302 				     const char *protocol,
303 				     const char *netid)
304 {
305 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
306 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
307 	xs_format_common_peer_addresses(xprt);
308 	xs_format_common_peer_ports(xprt);
309 }
310 
311 static void xs_update_peer_port(struct rpc_xprt *xprt)
312 {
313 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
314 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
315 
316 	xs_format_common_peer_ports(xprt);
317 }
318 
319 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
320 {
321 	unsigned int i;
322 
323 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
324 		switch (i) {
325 		case RPC_DISPLAY_PROTO:
326 		case RPC_DISPLAY_NETID:
327 			continue;
328 		default:
329 			kfree(xprt->address_strings[i]);
330 		}
331 }
332 
333 static size_t
334 xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
335 {
336 	size_t i,n;
337 
338 	if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES))
339 		return want;
340 	n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT;
341 	for (i = 0; i < n; i++) {
342 		if (buf->pages[i])
343 			continue;
344 		buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp);
345 		if (!buf->pages[i]) {
346 			i *= PAGE_SIZE;
347 			return i > buf->page_base ? i - buf->page_base : 0;
348 		}
349 	}
350 	return want;
351 }
352 
353 static ssize_t
354 xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
355 {
356 	ssize_t ret;
357 	if (seek != 0)
358 		iov_iter_advance(&msg->msg_iter, seek);
359 	ret = sock_recvmsg(sock, msg, flags);
360 	return ret > 0 ? ret + seek : ret;
361 }
362 
363 static ssize_t
364 xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags,
365 		struct kvec *kvec, size_t count, size_t seek)
366 {
367 	iov_iter_kvec(&msg->msg_iter, READ, kvec, 1, count);
368 	return xs_sock_recvmsg(sock, msg, flags, seek);
369 }
370 
371 static ssize_t
372 xs_read_bvec(struct socket *sock, struct msghdr *msg, int flags,
373 		struct bio_vec *bvec, unsigned long nr, size_t count,
374 		size_t seek)
375 {
376 	iov_iter_bvec(&msg->msg_iter, READ, bvec, nr, count);
377 	return xs_sock_recvmsg(sock, msg, flags, seek);
378 }
379 
380 static ssize_t
381 xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
382 		size_t count)
383 {
384 	iov_iter_discard(&msg->msg_iter, READ, count);
385 	return sock_recvmsg(sock, msg, flags);
386 }
387 
388 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
389 static void
390 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
391 {
392 	struct bvec_iter bi = {
393 		.bi_size = count,
394 	};
395 	struct bio_vec bv;
396 
397 	bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
398 	for_each_bvec(bv, bvec, bi, bi)
399 		flush_dcache_page(bv.bv_page);
400 }
401 #else
402 static inline void
403 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
404 {
405 }
406 #endif
407 
408 static ssize_t
409 xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
410 		struct xdr_buf *buf, size_t count, size_t seek, size_t *read)
411 {
412 	size_t want, seek_init = seek, offset = 0;
413 	ssize_t ret;
414 
415 	want = min_t(size_t, count, buf->head[0].iov_len);
416 	if (seek < want) {
417 		ret = xs_read_kvec(sock, msg, flags, &buf->head[0], want, seek);
418 		if (ret <= 0)
419 			goto sock_err;
420 		offset += ret;
421 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
422 			goto out;
423 		if (ret != want)
424 			goto out;
425 		seek = 0;
426 	} else {
427 		seek -= want;
428 		offset += want;
429 	}
430 
431 	want = xs_alloc_sparse_pages(
432 		buf, min_t(size_t, count - offset, buf->page_len),
433 		GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
434 	if (seek < want) {
435 		ret = xs_read_bvec(sock, msg, flags, buf->bvec,
436 				xdr_buf_pagecount(buf),
437 				want + buf->page_base,
438 				seek + buf->page_base);
439 		if (ret <= 0)
440 			goto sock_err;
441 		xs_flush_bvec(buf->bvec, ret, seek + buf->page_base);
442 		ret -= buf->page_base;
443 		offset += ret;
444 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
445 			goto out;
446 		if (ret != want)
447 			goto out;
448 		seek = 0;
449 	} else {
450 		seek -= want;
451 		offset += want;
452 	}
453 
454 	want = min_t(size_t, count - offset, buf->tail[0].iov_len);
455 	if (seek < want) {
456 		ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);
457 		if (ret <= 0)
458 			goto sock_err;
459 		offset += ret;
460 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
461 			goto out;
462 		if (ret != want)
463 			goto out;
464 	} else if (offset < seek_init)
465 		offset = seek_init;
466 	ret = -EMSGSIZE;
467 out:
468 	*read = offset - seek_init;
469 	return ret;
470 sock_err:
471 	offset += seek;
472 	goto out;
473 }
474 
475 static void
476 xs_read_header(struct sock_xprt *transport, struct xdr_buf *buf)
477 {
478 	if (!transport->recv.copied) {
479 		if (buf->head[0].iov_len >= transport->recv.offset)
480 			memcpy(buf->head[0].iov_base,
481 					&transport->recv.xid,
482 					transport->recv.offset);
483 		transport->recv.copied = transport->recv.offset;
484 	}
485 }
486 
487 static bool
488 xs_read_stream_request_done(struct sock_xprt *transport)
489 {
490 	return transport->recv.fraghdr & cpu_to_be32(RPC_LAST_STREAM_FRAGMENT);
491 }
492 
493 static void
494 xs_read_stream_check_eor(struct sock_xprt *transport,
495 		struct msghdr *msg)
496 {
497 	if (xs_read_stream_request_done(transport))
498 		msg->msg_flags |= MSG_EOR;
499 }
500 
501 static ssize_t
502 xs_read_stream_request(struct sock_xprt *transport, struct msghdr *msg,
503 		int flags, struct rpc_rqst *req)
504 {
505 	struct xdr_buf *buf = &req->rq_private_buf;
506 	size_t want, read;
507 	ssize_t ret;
508 
509 	xs_read_header(transport, buf);
510 
511 	want = transport->recv.len - transport->recv.offset;
512 	if (want != 0) {
513 		ret = xs_read_xdr_buf(transport->sock, msg, flags, buf,
514 				transport->recv.copied + want,
515 				transport->recv.copied,
516 				&read);
517 		transport->recv.offset += read;
518 		transport->recv.copied += read;
519 	}
520 
521 	if (transport->recv.offset == transport->recv.len)
522 		xs_read_stream_check_eor(transport, msg);
523 
524 	if (want == 0)
525 		return 0;
526 
527 	switch (ret) {
528 	default:
529 		break;
530 	case -EFAULT:
531 	case -EMSGSIZE:
532 		msg->msg_flags |= MSG_TRUNC;
533 		return read;
534 	case 0:
535 		return -ESHUTDOWN;
536 	}
537 	return ret < 0 ? ret : read;
538 }
539 
540 static size_t
541 xs_read_stream_headersize(bool isfrag)
542 {
543 	if (isfrag)
544 		return sizeof(__be32);
545 	return 3 * sizeof(__be32);
546 }
547 
548 static ssize_t
549 xs_read_stream_header(struct sock_xprt *transport, struct msghdr *msg,
550 		int flags, size_t want, size_t seek)
551 {
552 	struct kvec kvec = {
553 		.iov_base = &transport->recv.fraghdr,
554 		.iov_len = want,
555 	};
556 	return xs_read_kvec(transport->sock, msg, flags, &kvec, want, seek);
557 }
558 
559 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
560 static ssize_t
561 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
562 {
563 	struct rpc_xprt *xprt = &transport->xprt;
564 	struct rpc_rqst *req;
565 	ssize_t ret;
566 
567 	/* Is this transport associated with the backchannel? */
568 	if (!xprt->bc_serv)
569 		return -ESHUTDOWN;
570 
571 	/* Look up and lock the request corresponding to the given XID */
572 	req = xprt_lookup_bc_request(xprt, transport->recv.xid);
573 	if (!req) {
574 		printk(KERN_WARNING "Callback slot table overflowed\n");
575 		return -ESHUTDOWN;
576 	}
577 	if (transport->recv.copied && !req->rq_private_buf.len)
578 		return -ESHUTDOWN;
579 
580 	ret = xs_read_stream_request(transport, msg, flags, req);
581 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
582 		xprt_complete_bc_request(req, transport->recv.copied);
583 	else
584 		req->rq_private_buf.len = transport->recv.copied;
585 
586 	return ret;
587 }
588 #else /* CONFIG_SUNRPC_BACKCHANNEL */
589 static ssize_t
590 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
591 {
592 	return -ESHUTDOWN;
593 }
594 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
595 
596 static ssize_t
597 xs_read_stream_reply(struct sock_xprt *transport, struct msghdr *msg, int flags)
598 {
599 	struct rpc_xprt *xprt = &transport->xprt;
600 	struct rpc_rqst *req;
601 	ssize_t ret = 0;
602 
603 	/* Look up and lock the request corresponding to the given XID */
604 	spin_lock(&xprt->queue_lock);
605 	req = xprt_lookup_rqst(xprt, transport->recv.xid);
606 	if (!req || (transport->recv.copied && !req->rq_private_buf.len)) {
607 		msg->msg_flags |= MSG_TRUNC;
608 		goto out;
609 	}
610 	xprt_pin_rqst(req);
611 	spin_unlock(&xprt->queue_lock);
612 
613 	ret = xs_read_stream_request(transport, msg, flags, req);
614 
615 	spin_lock(&xprt->queue_lock);
616 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
617 		xprt_complete_rqst(req->rq_task, transport->recv.copied);
618 	else
619 		req->rq_private_buf.len = transport->recv.copied;
620 	xprt_unpin_rqst(req);
621 out:
622 	spin_unlock(&xprt->queue_lock);
623 	return ret;
624 }
625 
626 static ssize_t
627 xs_read_stream(struct sock_xprt *transport, int flags)
628 {
629 	struct msghdr msg = { 0 };
630 	size_t want, read = 0;
631 	ssize_t ret = 0;
632 
633 	if (transport->recv.len == 0) {
634 		want = xs_read_stream_headersize(transport->recv.copied != 0);
635 		ret = xs_read_stream_header(transport, &msg, flags, want,
636 				transport->recv.offset);
637 		if (ret <= 0)
638 			goto out_err;
639 		transport->recv.offset = ret;
640 		if (transport->recv.offset != want)
641 			return transport->recv.offset;
642 		transport->recv.len = be32_to_cpu(transport->recv.fraghdr) &
643 			RPC_FRAGMENT_SIZE_MASK;
644 		transport->recv.offset -= sizeof(transport->recv.fraghdr);
645 		read = ret;
646 	}
647 
648 	switch (be32_to_cpu(transport->recv.calldir)) {
649 	default:
650 		msg.msg_flags |= MSG_TRUNC;
651 		break;
652 	case RPC_CALL:
653 		ret = xs_read_stream_call(transport, &msg, flags);
654 		break;
655 	case RPC_REPLY:
656 		ret = xs_read_stream_reply(transport, &msg, flags);
657 	}
658 	if (msg.msg_flags & MSG_TRUNC) {
659 		transport->recv.calldir = cpu_to_be32(-1);
660 		transport->recv.copied = -1;
661 	}
662 	if (ret < 0)
663 		goto out_err;
664 	read += ret;
665 	if (transport->recv.offset < transport->recv.len) {
666 		if (!(msg.msg_flags & MSG_TRUNC))
667 			return read;
668 		msg.msg_flags = 0;
669 		ret = xs_read_discard(transport->sock, &msg, flags,
670 				transport->recv.len - transport->recv.offset);
671 		if (ret <= 0)
672 			goto out_err;
673 		transport->recv.offset += ret;
674 		read += ret;
675 		if (transport->recv.offset != transport->recv.len)
676 			return read;
677 	}
678 	if (xs_read_stream_request_done(transport)) {
679 		trace_xs_stream_read_request(transport);
680 		transport->recv.copied = 0;
681 	}
682 	transport->recv.offset = 0;
683 	transport->recv.len = 0;
684 	return read;
685 out_err:
686 	return ret != 0 ? ret : -ESHUTDOWN;
687 }
688 
689 static __poll_t xs_poll_socket(struct sock_xprt *transport)
690 {
691 	return transport->sock->ops->poll(transport->file, transport->sock,
692 			NULL);
693 }
694 
695 static bool xs_poll_socket_readable(struct sock_xprt *transport)
696 {
697 	__poll_t events = xs_poll_socket(transport);
698 
699 	return (events & (EPOLLIN | EPOLLRDNORM)) && !(events & EPOLLRDHUP);
700 }
701 
702 static void xs_poll_check_readable(struct sock_xprt *transport)
703 {
704 
705 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
706 	if (!xs_poll_socket_readable(transport))
707 		return;
708 	if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
709 		queue_work(xprtiod_workqueue, &transport->recv_worker);
710 }
711 
712 static void xs_stream_data_receive(struct sock_xprt *transport)
713 {
714 	size_t read = 0;
715 	ssize_t ret = 0;
716 
717 	mutex_lock(&transport->recv_mutex);
718 	if (transport->sock == NULL)
719 		goto out;
720 	for (;;) {
721 		ret = xs_read_stream(transport, MSG_DONTWAIT);
722 		if (ret < 0)
723 			break;
724 		read += ret;
725 		cond_resched();
726 	}
727 	if (ret == -ESHUTDOWN)
728 		kernel_sock_shutdown(transport->sock, SHUT_RDWR);
729 	else
730 		xs_poll_check_readable(transport);
731 out:
732 	mutex_unlock(&transport->recv_mutex);
733 	trace_xs_stream_read_data(&transport->xprt, ret, read);
734 }
735 
736 static void xs_stream_data_receive_workfn(struct work_struct *work)
737 {
738 	struct sock_xprt *transport =
739 		container_of(work, struct sock_xprt, recv_worker);
740 	unsigned int pflags = memalloc_nofs_save();
741 
742 	xs_stream_data_receive(transport);
743 	memalloc_nofs_restore(pflags);
744 }
745 
746 static void
747 xs_stream_reset_connect(struct sock_xprt *transport)
748 {
749 	transport->recv.offset = 0;
750 	transport->recv.len = 0;
751 	transport->recv.copied = 0;
752 	transport->xmit.offset = 0;
753 }
754 
755 static void
756 xs_stream_start_connect(struct sock_xprt *transport)
757 {
758 	transport->xprt.stat.connect_count++;
759 	transport->xprt.stat.connect_start = jiffies;
760 }
761 
762 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
763 
764 /**
765  * xs_nospace - handle transmit was incomplete
766  * @req: pointer to RPC request
767  * @transport: pointer to struct sock_xprt
768  *
769  */
770 static int xs_nospace(struct rpc_rqst *req, struct sock_xprt *transport)
771 {
772 	struct rpc_xprt *xprt = &transport->xprt;
773 	struct sock *sk = transport->inet;
774 	int ret = -EAGAIN;
775 
776 	trace_rpc_socket_nospace(req, transport);
777 
778 	/* Protect against races with write_space */
779 	spin_lock(&xprt->transport_lock);
780 
781 	/* Don't race with disconnect */
782 	if (xprt_connected(xprt)) {
783 		/* wait for more buffer space */
784 		set_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
785 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
786 		sk->sk_write_pending++;
787 		xprt_wait_for_buffer_space(xprt);
788 	} else
789 		ret = -ENOTCONN;
790 
791 	spin_unlock(&xprt->transport_lock);
792 	return ret;
793 }
794 
795 static int xs_sock_nospace(struct rpc_rqst *req)
796 {
797 	struct sock_xprt *transport =
798 		container_of(req->rq_xprt, struct sock_xprt, xprt);
799 	struct sock *sk = transport->inet;
800 	int ret = -EAGAIN;
801 
802 	lock_sock(sk);
803 	if (!sock_writeable(sk))
804 		ret = xs_nospace(req, transport);
805 	release_sock(sk);
806 	return ret;
807 }
808 
809 static int xs_stream_nospace(struct rpc_rqst *req, bool vm_wait)
810 {
811 	struct sock_xprt *transport =
812 		container_of(req->rq_xprt, struct sock_xprt, xprt);
813 	struct sock *sk = transport->inet;
814 	int ret = -EAGAIN;
815 
816 	if (vm_wait)
817 		return -ENOBUFS;
818 	lock_sock(sk);
819 	if (!sk_stream_memory_free(sk))
820 		ret = xs_nospace(req, transport);
821 	release_sock(sk);
822 	return ret;
823 }
824 
825 static int xs_stream_prepare_request(struct rpc_rqst *req, struct xdr_buf *buf)
826 {
827 	return xdr_alloc_bvec(buf, rpc_task_gfp_mask());
828 }
829 
830 /*
831  * Determine if the previous message in the stream was aborted before it
832  * could complete transmission.
833  */
834 static bool
835 xs_send_request_was_aborted(struct sock_xprt *transport, struct rpc_rqst *req)
836 {
837 	return transport->xmit.offset != 0 && req->rq_bytes_sent == 0;
838 }
839 
840 /*
841  * Return the stream record marker field for a record of length < 2^31-1
842  */
843 static rpc_fraghdr
844 xs_stream_record_marker(struct xdr_buf *xdr)
845 {
846 	if (!xdr->len)
847 		return 0;
848 	return cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | (u32)xdr->len);
849 }
850 
851 /**
852  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
853  * @req: pointer to RPC request
854  *
855  * Return values:
856  *        0:	The request has been sent
857  *   EAGAIN:	The socket was blocked, please call again later to
858  *		complete the request
859  * ENOTCONN:	Caller needs to invoke connect logic then call again
860  *    other:	Some other error occurred, the request was not sent
861  */
862 static int xs_local_send_request(struct rpc_rqst *req)
863 {
864 	struct rpc_xprt *xprt = req->rq_xprt;
865 	struct sock_xprt *transport =
866 				container_of(xprt, struct sock_xprt, xprt);
867 	struct xdr_buf *xdr = &req->rq_snd_buf;
868 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
869 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
870 	struct msghdr msg = {
871 		.msg_flags	= XS_SENDMSG_FLAGS,
872 	};
873 	bool vm_wait;
874 	unsigned int sent;
875 	int status;
876 
877 	/* Close the stream if the previous transmission was incomplete */
878 	if (xs_send_request_was_aborted(transport, req)) {
879 		xprt_force_disconnect(xprt);
880 		return -ENOTCONN;
881 	}
882 
883 	xs_pktdump("packet data:",
884 			req->rq_svec->iov_base, req->rq_svec->iov_len);
885 
886 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
887 
888 	req->rq_xtime = ktime_get();
889 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
890 				   transport->xmit.offset, rm, &sent);
891 	dprintk("RPC:       %s(%u) = %d\n",
892 			__func__, xdr->len - transport->xmit.offset, status);
893 
894 	if (likely(sent > 0) || status == 0) {
895 		transport->xmit.offset += sent;
896 		req->rq_bytes_sent = transport->xmit.offset;
897 		if (likely(req->rq_bytes_sent >= msglen)) {
898 			req->rq_xmit_bytes_sent += transport->xmit.offset;
899 			transport->xmit.offset = 0;
900 			return 0;
901 		}
902 		status = -EAGAIN;
903 		vm_wait = false;
904 	}
905 
906 	switch (status) {
907 	case -EAGAIN:
908 		status = xs_stream_nospace(req, vm_wait);
909 		break;
910 	default:
911 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
912 			-status);
913 		fallthrough;
914 	case -EPIPE:
915 		xprt_force_disconnect(xprt);
916 		status = -ENOTCONN;
917 	}
918 
919 	return status;
920 }
921 
922 /**
923  * xs_udp_send_request - write an RPC request to a UDP socket
924  * @req: pointer to RPC request
925  *
926  * Return values:
927  *        0:	The request has been sent
928  *   EAGAIN:	The socket was blocked, please call again later to
929  *		complete the request
930  * ENOTCONN:	Caller needs to invoke connect logic then call again
931  *    other:	Some other error occurred, the request was not sent
932  */
933 static int xs_udp_send_request(struct rpc_rqst *req)
934 {
935 	struct rpc_xprt *xprt = req->rq_xprt;
936 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
937 	struct xdr_buf *xdr = &req->rq_snd_buf;
938 	struct msghdr msg = {
939 		.msg_name	= xs_addr(xprt),
940 		.msg_namelen	= xprt->addrlen,
941 		.msg_flags	= XS_SENDMSG_FLAGS,
942 	};
943 	unsigned int sent;
944 	int status;
945 
946 	xs_pktdump("packet data:",
947 				req->rq_svec->iov_base,
948 				req->rq_svec->iov_len);
949 
950 	if (!xprt_bound(xprt))
951 		return -ENOTCONN;
952 
953 	if (!xprt_request_get_cong(xprt, req))
954 		return -EBADSLT;
955 
956 	status = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
957 	if (status < 0)
958 		return status;
959 	req->rq_xtime = ktime_get();
960 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, 0, &sent);
961 
962 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
963 			xdr->len, status);
964 
965 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
966 	if (status == -EPERM)
967 		goto process_status;
968 
969 	if (status == -EAGAIN && sock_writeable(transport->inet))
970 		status = -ENOBUFS;
971 
972 	if (sent > 0 || status == 0) {
973 		req->rq_xmit_bytes_sent += sent;
974 		if (sent >= req->rq_slen)
975 			return 0;
976 		/* Still some bytes left; set up for a retry later. */
977 		status = -EAGAIN;
978 	}
979 
980 process_status:
981 	switch (status) {
982 	case -ENOTSOCK:
983 		status = -ENOTCONN;
984 		/* Should we call xs_close() here? */
985 		break;
986 	case -EAGAIN:
987 		status = xs_sock_nospace(req);
988 		break;
989 	case -ENETUNREACH:
990 	case -ENOBUFS:
991 	case -EPIPE:
992 	case -ECONNREFUSED:
993 	case -EPERM:
994 		/* When the server has died, an ICMP port unreachable message
995 		 * prompts ECONNREFUSED. */
996 		break;
997 	default:
998 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
999 			-status);
1000 	}
1001 
1002 	return status;
1003 }
1004 
1005 /**
1006  * xs_tcp_send_request - write an RPC request to a TCP socket
1007  * @req: pointer to RPC request
1008  *
1009  * Return values:
1010  *        0:	The request has been sent
1011  *   EAGAIN:	The socket was blocked, please call again later to
1012  *		complete the request
1013  * ENOTCONN:	Caller needs to invoke connect logic then call again
1014  *    other:	Some other error occurred, the request was not sent
1015  *
1016  * XXX: In the case of soft timeouts, should we eventually give up
1017  *	if sendmsg is not able to make progress?
1018  */
1019 static int xs_tcp_send_request(struct rpc_rqst *req)
1020 {
1021 	struct rpc_xprt *xprt = req->rq_xprt;
1022 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1023 	struct xdr_buf *xdr = &req->rq_snd_buf;
1024 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
1025 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
1026 	struct msghdr msg = {
1027 		.msg_flags	= XS_SENDMSG_FLAGS,
1028 	};
1029 	bool vm_wait;
1030 	unsigned int sent;
1031 	int status;
1032 
1033 	/* Close the stream if the previous transmission was incomplete */
1034 	if (xs_send_request_was_aborted(transport, req)) {
1035 		if (transport->sock != NULL)
1036 			kernel_sock_shutdown(transport->sock, SHUT_RDWR);
1037 		return -ENOTCONN;
1038 	}
1039 	if (!transport->inet)
1040 		return -ENOTCONN;
1041 
1042 	xs_pktdump("packet data:",
1043 				req->rq_svec->iov_base,
1044 				req->rq_svec->iov_len);
1045 
1046 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
1047 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
1048 
1049 	xs_set_srcport(transport, transport->sock);
1050 
1051 	/* Continue transmitting the packet/record. We must be careful
1052 	 * to cope with writespace callbacks arriving _after_ we have
1053 	 * called sendmsg(). */
1054 	req->rq_xtime = ktime_get();
1055 	tcp_sock_set_cork(transport->inet, true);
1056 
1057 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
1058 
1059 	do {
1060 		status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
1061 					   transport->xmit.offset, rm, &sent);
1062 
1063 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
1064 				xdr->len - transport->xmit.offset, status);
1065 
1066 		/* If we've sent the entire packet, immediately
1067 		 * reset the count of bytes sent. */
1068 		transport->xmit.offset += sent;
1069 		req->rq_bytes_sent = transport->xmit.offset;
1070 		if (likely(req->rq_bytes_sent >= msglen)) {
1071 			req->rq_xmit_bytes_sent += transport->xmit.offset;
1072 			transport->xmit.offset = 0;
1073 			if (atomic_long_read(&xprt->xmit_queuelen) == 1)
1074 				tcp_sock_set_cork(transport->inet, false);
1075 			return 0;
1076 		}
1077 
1078 		WARN_ON_ONCE(sent == 0 && status == 0);
1079 
1080 		if (sent > 0)
1081 			vm_wait = false;
1082 
1083 	} while (status == 0);
1084 
1085 	switch (status) {
1086 	case -ENOTSOCK:
1087 		status = -ENOTCONN;
1088 		/* Should we call xs_close() here? */
1089 		break;
1090 	case -EAGAIN:
1091 		status = xs_stream_nospace(req, vm_wait);
1092 		break;
1093 	case -ECONNRESET:
1094 	case -ECONNREFUSED:
1095 	case -ENOTCONN:
1096 	case -EADDRINUSE:
1097 	case -ENOBUFS:
1098 	case -EPIPE:
1099 		break;
1100 	default:
1101 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1102 			-status);
1103 	}
1104 
1105 	return status;
1106 }
1107 
1108 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1109 {
1110 	transport->old_data_ready = sk->sk_data_ready;
1111 	transport->old_state_change = sk->sk_state_change;
1112 	transport->old_write_space = sk->sk_write_space;
1113 	transport->old_error_report = sk->sk_error_report;
1114 }
1115 
1116 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1117 {
1118 	sk->sk_data_ready = transport->old_data_ready;
1119 	sk->sk_state_change = transport->old_state_change;
1120 	sk->sk_write_space = transport->old_write_space;
1121 	sk->sk_error_report = transport->old_error_report;
1122 }
1123 
1124 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
1125 {
1126 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1127 
1128 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1129 	clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state);
1130 	clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state);
1131 	clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state);
1132 	clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
1133 }
1134 
1135 static void xs_run_error_worker(struct sock_xprt *transport, unsigned int nr)
1136 {
1137 	set_bit(nr, &transport->sock_state);
1138 	queue_work(xprtiod_workqueue, &transport->error_worker);
1139 }
1140 
1141 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1142 {
1143 	xprt->connect_cookie++;
1144 	smp_mb__before_atomic();
1145 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1146 	clear_bit(XPRT_CLOSING, &xprt->state);
1147 	xs_sock_reset_state_flags(xprt);
1148 	smp_mb__after_atomic();
1149 }
1150 
1151 /**
1152  * xs_error_report - callback to handle TCP socket state errors
1153  * @sk: socket
1154  *
1155  * Note: we don't call sock_error() since there may be a rpc_task
1156  * using the socket, and so we don't want to clear sk->sk_err.
1157  */
1158 static void xs_error_report(struct sock *sk)
1159 {
1160 	struct sock_xprt *transport;
1161 	struct rpc_xprt *xprt;
1162 
1163 	if (!(xprt = xprt_from_sock(sk)))
1164 		return;
1165 
1166 	transport = container_of(xprt, struct sock_xprt, xprt);
1167 	transport->xprt_err = -sk->sk_err;
1168 	if (transport->xprt_err == 0)
1169 		return;
1170 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
1171 			xprt, -transport->xprt_err);
1172 	trace_rpc_socket_error(xprt, sk->sk_socket, transport->xprt_err);
1173 
1174 	/* barrier ensures xprt_err is set before XPRT_SOCK_WAKE_ERROR */
1175 	smp_mb__before_atomic();
1176 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_ERROR);
1177 }
1178 
1179 static void xs_reset_transport(struct sock_xprt *transport)
1180 {
1181 	struct socket *sock = transport->sock;
1182 	struct sock *sk = transport->inet;
1183 	struct rpc_xprt *xprt = &transport->xprt;
1184 	struct file *filp = transport->file;
1185 
1186 	if (sk == NULL)
1187 		return;
1188 	/*
1189 	 * Make sure we're calling this in a context from which it is safe
1190 	 * to call __fput_sync(). In practice that means rpciod and the
1191 	 * system workqueue.
1192 	 */
1193 	if (!(current->flags & PF_WQ_WORKER)) {
1194 		WARN_ON_ONCE(1);
1195 		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
1196 		return;
1197 	}
1198 
1199 	if (atomic_read(&transport->xprt.swapper))
1200 		sk_clear_memalloc(sk);
1201 
1202 	kernel_sock_shutdown(sock, SHUT_RDWR);
1203 
1204 	mutex_lock(&transport->recv_mutex);
1205 	lock_sock(sk);
1206 	transport->inet = NULL;
1207 	transport->sock = NULL;
1208 	transport->file = NULL;
1209 
1210 	sk->sk_user_data = NULL;
1211 
1212 	xs_restore_old_callbacks(transport, sk);
1213 	xprt_clear_connected(xprt);
1214 	xs_sock_reset_connection_flags(xprt);
1215 	/* Reset stream record info */
1216 	xs_stream_reset_connect(transport);
1217 	release_sock(sk);
1218 	mutex_unlock(&transport->recv_mutex);
1219 
1220 	trace_rpc_socket_close(xprt, sock);
1221 	__fput_sync(filp);
1222 
1223 	xprt_disconnect_done(xprt);
1224 }
1225 
1226 /**
1227  * xs_close - close a socket
1228  * @xprt: transport
1229  *
1230  * This is used when all requests are complete; ie, no DRC state remains
1231  * on the server we want to save.
1232  *
1233  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
1234  * xs_reset_transport() zeroing the socket from underneath a writer.
1235  */
1236 static void xs_close(struct rpc_xprt *xprt)
1237 {
1238 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1239 
1240 	dprintk("RPC:       xs_close xprt %p\n", xprt);
1241 
1242 	xs_reset_transport(transport);
1243 	xprt->reestablish_timeout = 0;
1244 }
1245 
1246 static void xs_inject_disconnect(struct rpc_xprt *xprt)
1247 {
1248 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
1249 		xprt);
1250 	xprt_disconnect_done(xprt);
1251 }
1252 
1253 static void xs_xprt_free(struct rpc_xprt *xprt)
1254 {
1255 	xs_free_peer_addresses(xprt);
1256 	xprt_free(xprt);
1257 }
1258 
1259 /**
1260  * xs_destroy - prepare to shutdown a transport
1261  * @xprt: doomed transport
1262  *
1263  */
1264 static void xs_destroy(struct rpc_xprt *xprt)
1265 {
1266 	struct sock_xprt *transport = container_of(xprt,
1267 			struct sock_xprt, xprt);
1268 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
1269 
1270 	cancel_delayed_work_sync(&transport->connect_worker);
1271 	xs_close(xprt);
1272 	cancel_work_sync(&transport->recv_worker);
1273 	cancel_work_sync(&transport->error_worker);
1274 	xs_xprt_free(xprt);
1275 	module_put(THIS_MODULE);
1276 }
1277 
1278 /**
1279  * xs_udp_data_read_skb - receive callback for UDP sockets
1280  * @xprt: transport
1281  * @sk: socket
1282  * @skb: skbuff
1283  *
1284  */
1285 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1286 		struct sock *sk,
1287 		struct sk_buff *skb)
1288 {
1289 	struct rpc_task *task;
1290 	struct rpc_rqst *rovr;
1291 	int repsize, copied;
1292 	u32 _xid;
1293 	__be32 *xp;
1294 
1295 	repsize = skb->len;
1296 	if (repsize < 4) {
1297 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1298 		return;
1299 	}
1300 
1301 	/* Copy the XID from the skb... */
1302 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1303 	if (xp == NULL)
1304 		return;
1305 
1306 	/* Look up and lock the request corresponding to the given XID */
1307 	spin_lock(&xprt->queue_lock);
1308 	rovr = xprt_lookup_rqst(xprt, *xp);
1309 	if (!rovr)
1310 		goto out_unlock;
1311 	xprt_pin_rqst(rovr);
1312 	xprt_update_rtt(rovr->rq_task);
1313 	spin_unlock(&xprt->queue_lock);
1314 	task = rovr->rq_task;
1315 
1316 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1317 		copied = repsize;
1318 
1319 	/* Suck it into the iovec, verify checksum if not done by hw. */
1320 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1321 		spin_lock(&xprt->queue_lock);
1322 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1323 		goto out_unpin;
1324 	}
1325 
1326 
1327 	spin_lock(&xprt->transport_lock);
1328 	xprt_adjust_cwnd(xprt, task, copied);
1329 	spin_unlock(&xprt->transport_lock);
1330 	spin_lock(&xprt->queue_lock);
1331 	xprt_complete_rqst(task, copied);
1332 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1333 out_unpin:
1334 	xprt_unpin_rqst(rovr);
1335  out_unlock:
1336 	spin_unlock(&xprt->queue_lock);
1337 }
1338 
1339 static void xs_udp_data_receive(struct sock_xprt *transport)
1340 {
1341 	struct sk_buff *skb;
1342 	struct sock *sk;
1343 	int err;
1344 
1345 	mutex_lock(&transport->recv_mutex);
1346 	sk = transport->inet;
1347 	if (sk == NULL)
1348 		goto out;
1349 	for (;;) {
1350 		skb = skb_recv_udp(sk, MSG_DONTWAIT, &err);
1351 		if (skb == NULL)
1352 			break;
1353 		xs_udp_data_read_skb(&transport->xprt, sk, skb);
1354 		consume_skb(skb);
1355 		cond_resched();
1356 	}
1357 	xs_poll_check_readable(transport);
1358 out:
1359 	mutex_unlock(&transport->recv_mutex);
1360 }
1361 
1362 static void xs_udp_data_receive_workfn(struct work_struct *work)
1363 {
1364 	struct sock_xprt *transport =
1365 		container_of(work, struct sock_xprt, recv_worker);
1366 	unsigned int pflags = memalloc_nofs_save();
1367 
1368 	xs_udp_data_receive(transport);
1369 	memalloc_nofs_restore(pflags);
1370 }
1371 
1372 /**
1373  * xs_data_ready - "data ready" callback for sockets
1374  * @sk: socket with data to read
1375  *
1376  */
1377 static void xs_data_ready(struct sock *sk)
1378 {
1379 	struct rpc_xprt *xprt;
1380 
1381 	xprt = xprt_from_sock(sk);
1382 	if (xprt != NULL) {
1383 		struct sock_xprt *transport = container_of(xprt,
1384 				struct sock_xprt, xprt);
1385 
1386 		trace_xs_data_ready(xprt);
1387 
1388 		transport->old_data_ready(sk);
1389 		/* Any data means we had a useful conversation, so
1390 		 * then we don't need to delay the next reconnect
1391 		 */
1392 		if (xprt->reestablish_timeout)
1393 			xprt->reestablish_timeout = 0;
1394 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1395 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1396 	}
1397 }
1398 
1399 /*
1400  * Helper function to force a TCP close if the server is sending
1401  * junk and/or it has put us in CLOSE_WAIT
1402  */
1403 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1404 {
1405 	xprt_force_disconnect(xprt);
1406 }
1407 
1408 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1409 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1410 {
1411 	return PAGE_SIZE;
1412 }
1413 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1414 
1415 /**
1416  * xs_local_state_change - callback to handle AF_LOCAL socket state changes
1417  * @sk: socket whose state has changed
1418  *
1419  */
1420 static void xs_local_state_change(struct sock *sk)
1421 {
1422 	struct rpc_xprt *xprt;
1423 	struct sock_xprt *transport;
1424 
1425 	if (!(xprt = xprt_from_sock(sk)))
1426 		return;
1427 	transport = container_of(xprt, struct sock_xprt, xprt);
1428 	if (sk->sk_shutdown & SHUTDOWN_MASK) {
1429 		clear_bit(XPRT_CONNECTED, &xprt->state);
1430 		/* Trigger the socket release */
1431 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1432 	}
1433 }
1434 
1435 /**
1436  * xs_tcp_state_change - callback to handle TCP socket state changes
1437  * @sk: socket whose state has changed
1438  *
1439  */
1440 static void xs_tcp_state_change(struct sock *sk)
1441 {
1442 	struct rpc_xprt *xprt;
1443 	struct sock_xprt *transport;
1444 
1445 	if (!(xprt = xprt_from_sock(sk)))
1446 		return;
1447 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1448 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1449 			sk->sk_state, xprt_connected(xprt),
1450 			sock_flag(sk, SOCK_DEAD),
1451 			sock_flag(sk, SOCK_ZAPPED),
1452 			sk->sk_shutdown);
1453 
1454 	transport = container_of(xprt, struct sock_xprt, xprt);
1455 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1456 	switch (sk->sk_state) {
1457 	case TCP_ESTABLISHED:
1458 		if (!xprt_test_and_set_connected(xprt)) {
1459 			xprt->connect_cookie++;
1460 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1461 			xprt_clear_connecting(xprt);
1462 
1463 			xprt->stat.connect_count++;
1464 			xprt->stat.connect_time += (long)jiffies -
1465 						   xprt->stat.connect_start;
1466 			xs_run_error_worker(transport, XPRT_SOCK_WAKE_PENDING);
1467 		}
1468 		break;
1469 	case TCP_FIN_WAIT1:
1470 		/* The client initiated a shutdown of the socket */
1471 		xprt->connect_cookie++;
1472 		xprt->reestablish_timeout = 0;
1473 		set_bit(XPRT_CLOSING, &xprt->state);
1474 		smp_mb__before_atomic();
1475 		clear_bit(XPRT_CONNECTED, &xprt->state);
1476 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1477 		smp_mb__after_atomic();
1478 		break;
1479 	case TCP_CLOSE_WAIT:
1480 		/* The server initiated a shutdown of the socket */
1481 		xprt->connect_cookie++;
1482 		clear_bit(XPRT_CONNECTED, &xprt->state);
1483 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1484 		fallthrough;
1485 	case TCP_CLOSING:
1486 		/*
1487 		 * If the server closed down the connection, make sure that
1488 		 * we back off before reconnecting
1489 		 */
1490 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1491 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1492 		break;
1493 	case TCP_LAST_ACK:
1494 		set_bit(XPRT_CLOSING, &xprt->state);
1495 		smp_mb__before_atomic();
1496 		clear_bit(XPRT_CONNECTED, &xprt->state);
1497 		smp_mb__after_atomic();
1498 		break;
1499 	case TCP_CLOSE:
1500 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1501 					&transport->sock_state))
1502 			xprt_clear_connecting(xprt);
1503 		clear_bit(XPRT_CLOSING, &xprt->state);
1504 		/* Trigger the socket release */
1505 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1506 	}
1507 }
1508 
1509 static void xs_write_space(struct sock *sk)
1510 {
1511 	struct sock_xprt *transport;
1512 	struct rpc_xprt *xprt;
1513 
1514 	if (!sk->sk_socket)
1515 		return;
1516 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1517 
1518 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1519 		return;
1520 	transport = container_of(xprt, struct sock_xprt, xprt);
1521 	if (!test_and_clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state))
1522 		return;
1523 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_WRITE);
1524 	sk->sk_write_pending--;
1525 }
1526 
1527 /**
1528  * xs_udp_write_space - callback invoked when socket buffer space
1529  *                             becomes available
1530  * @sk: socket whose state has changed
1531  *
1532  * Called when more output buffer space is available for this socket.
1533  * We try not to wake our writers until they can make "significant"
1534  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1535  * with a bunch of small requests.
1536  */
1537 static void xs_udp_write_space(struct sock *sk)
1538 {
1539 	/* from net/core/sock.c:sock_def_write_space */
1540 	if (sock_writeable(sk))
1541 		xs_write_space(sk);
1542 }
1543 
1544 /**
1545  * xs_tcp_write_space - callback invoked when socket buffer space
1546  *                             becomes available
1547  * @sk: socket whose state has changed
1548  *
1549  * Called when more output buffer space is available for this socket.
1550  * We try not to wake our writers until they can make "significant"
1551  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1552  * with a bunch of small requests.
1553  */
1554 static void xs_tcp_write_space(struct sock *sk)
1555 {
1556 	/* from net/core/stream.c:sk_stream_write_space */
1557 	if (sk_stream_is_writeable(sk))
1558 		xs_write_space(sk);
1559 }
1560 
1561 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1562 {
1563 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1564 	struct sock *sk = transport->inet;
1565 
1566 	if (transport->rcvsize) {
1567 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1568 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1569 	}
1570 	if (transport->sndsize) {
1571 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1572 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1573 		sk->sk_write_space(sk);
1574 	}
1575 }
1576 
1577 /**
1578  * xs_udp_set_buffer_size - set send and receive limits
1579  * @xprt: generic transport
1580  * @sndsize: requested size of send buffer, in bytes
1581  * @rcvsize: requested size of receive buffer, in bytes
1582  *
1583  * Set socket send and receive buffer size limits.
1584  */
1585 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1586 {
1587 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1588 
1589 	transport->sndsize = 0;
1590 	if (sndsize)
1591 		transport->sndsize = sndsize + 1024;
1592 	transport->rcvsize = 0;
1593 	if (rcvsize)
1594 		transport->rcvsize = rcvsize + 1024;
1595 
1596 	xs_udp_do_set_buffer_size(xprt);
1597 }
1598 
1599 /**
1600  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1601  * @xprt: controlling transport
1602  * @task: task that timed out
1603  *
1604  * Adjust the congestion window after a retransmit timeout has occurred.
1605  */
1606 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1607 {
1608 	spin_lock(&xprt->transport_lock);
1609 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1610 	spin_unlock(&xprt->transport_lock);
1611 }
1612 
1613 static int xs_get_random_port(void)
1614 {
1615 	unsigned short min = xprt_min_resvport, max = xprt_max_resvport;
1616 	unsigned short range;
1617 	unsigned short rand;
1618 
1619 	if (max < min)
1620 		return -EADDRINUSE;
1621 	range = max - min + 1;
1622 	rand = (unsigned short) prandom_u32() % range;
1623 	return rand + min;
1624 }
1625 
1626 static unsigned short xs_sock_getport(struct socket *sock)
1627 {
1628 	struct sockaddr_storage buf;
1629 	unsigned short port = 0;
1630 
1631 	if (kernel_getsockname(sock, (struct sockaddr *)&buf) < 0)
1632 		goto out;
1633 	switch (buf.ss_family) {
1634 	case AF_INET6:
1635 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1636 		break;
1637 	case AF_INET:
1638 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1639 	}
1640 out:
1641 	return port;
1642 }
1643 
1644 /**
1645  * xs_set_port - reset the port number in the remote endpoint address
1646  * @xprt: generic transport
1647  * @port: new port number
1648  *
1649  */
1650 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1651 {
1652 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1653 
1654 	rpc_set_port(xs_addr(xprt), port);
1655 	xs_update_peer_port(xprt);
1656 }
1657 
1658 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1659 {
1660 	if (transport->srcport == 0 && transport->xprt.reuseport)
1661 		transport->srcport = xs_sock_getport(sock);
1662 }
1663 
1664 static int xs_get_srcport(struct sock_xprt *transport)
1665 {
1666 	int port = transport->srcport;
1667 
1668 	if (port == 0 && transport->xprt.resvport)
1669 		port = xs_get_random_port();
1670 	return port;
1671 }
1672 
1673 static unsigned short xs_sock_srcport(struct rpc_xprt *xprt)
1674 {
1675 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1676 	unsigned short ret = 0;
1677 	mutex_lock(&sock->recv_mutex);
1678 	if (sock->sock)
1679 		ret = xs_sock_getport(sock->sock);
1680 	mutex_unlock(&sock->recv_mutex);
1681 	return ret;
1682 }
1683 
1684 static int xs_sock_srcaddr(struct rpc_xprt *xprt, char *buf, size_t buflen)
1685 {
1686 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1687 	union {
1688 		struct sockaddr sa;
1689 		struct sockaddr_storage st;
1690 	} saddr;
1691 	int ret = -ENOTCONN;
1692 
1693 	mutex_lock(&sock->recv_mutex);
1694 	if (sock->sock) {
1695 		ret = kernel_getsockname(sock->sock, &saddr.sa);
1696 		if (ret >= 0)
1697 			ret = snprintf(buf, buflen, "%pISc", &saddr.sa);
1698 	}
1699 	mutex_unlock(&sock->recv_mutex);
1700 	return ret;
1701 }
1702 
1703 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1704 {
1705 	if (transport->srcport != 0)
1706 		transport->srcport = 0;
1707 	if (!transport->xprt.resvport)
1708 		return 0;
1709 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1710 		return xprt_max_resvport;
1711 	return --port;
1712 }
1713 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1714 {
1715 	struct sockaddr_storage myaddr;
1716 	int err, nloop = 0;
1717 	int port = xs_get_srcport(transport);
1718 	unsigned short last;
1719 
1720 	/*
1721 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1722 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1723 	 * port selection happen implicitly when the socket is used
1724 	 * (for example at connect time).
1725 	 *
1726 	 * This ensures that we can continue to establish TCP
1727 	 * connections even when all local ephemeral ports are already
1728 	 * a part of some TCP connection.  This makes no difference
1729 	 * for UDP sockets, but also doesn't harm them.
1730 	 *
1731 	 * If we're asking for any reserved port (i.e. port == 0 &&
1732 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1733 	 * ensure that port is non-zero and we will bind as needed.
1734 	 */
1735 	if (port <= 0)
1736 		return port;
1737 
1738 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1739 	do {
1740 		rpc_set_port((struct sockaddr *)&myaddr, port);
1741 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1742 				transport->xprt.addrlen);
1743 		if (err == 0) {
1744 			if (transport->xprt.reuseport)
1745 				transport->srcport = port;
1746 			break;
1747 		}
1748 		last = port;
1749 		port = xs_next_srcport(transport, port);
1750 		if (port > last)
1751 			nloop++;
1752 	} while (err == -EADDRINUSE && nloop != 2);
1753 
1754 	if (myaddr.ss_family == AF_INET)
1755 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1756 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1757 				port, err ? "failed" : "ok", err);
1758 	else
1759 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1760 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1761 				port, err ? "failed" : "ok", err);
1762 	return err;
1763 }
1764 
1765 /*
1766  * We don't support autobind on AF_LOCAL sockets
1767  */
1768 static void xs_local_rpcbind(struct rpc_task *task)
1769 {
1770 	xprt_set_bound(task->tk_xprt);
1771 }
1772 
1773 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1774 {
1775 }
1776 
1777 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1778 static struct lock_class_key xs_key[3];
1779 static struct lock_class_key xs_slock_key[3];
1780 
1781 static inline void xs_reclassify_socketu(struct socket *sock)
1782 {
1783 	struct sock *sk = sock->sk;
1784 
1785 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1786 		&xs_slock_key[0], "sk_lock-AF_LOCAL-RPC", &xs_key[0]);
1787 }
1788 
1789 static inline void xs_reclassify_socket4(struct socket *sock)
1790 {
1791 	struct sock *sk = sock->sk;
1792 
1793 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1794 		&xs_slock_key[1], "sk_lock-AF_INET-RPC", &xs_key[1]);
1795 }
1796 
1797 static inline void xs_reclassify_socket6(struct socket *sock)
1798 {
1799 	struct sock *sk = sock->sk;
1800 
1801 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1802 		&xs_slock_key[2], "sk_lock-AF_INET6-RPC", &xs_key[2]);
1803 }
1804 
1805 static inline void xs_reclassify_socket(int family, struct socket *sock)
1806 {
1807 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1808 		return;
1809 
1810 	switch (family) {
1811 	case AF_LOCAL:
1812 		xs_reclassify_socketu(sock);
1813 		break;
1814 	case AF_INET:
1815 		xs_reclassify_socket4(sock);
1816 		break;
1817 	case AF_INET6:
1818 		xs_reclassify_socket6(sock);
1819 		break;
1820 	}
1821 }
1822 #else
1823 static inline void xs_reclassify_socket(int family, struct socket *sock)
1824 {
1825 }
1826 #endif
1827 
1828 static void xs_dummy_setup_socket(struct work_struct *work)
1829 {
1830 }
1831 
1832 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1833 		struct sock_xprt *transport, int family, int type,
1834 		int protocol, bool reuseport)
1835 {
1836 	struct file *filp;
1837 	struct socket *sock;
1838 	int err;
1839 
1840 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1841 	if (err < 0) {
1842 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1843 				protocol, -err);
1844 		goto out;
1845 	}
1846 	xs_reclassify_socket(family, sock);
1847 
1848 	if (reuseport)
1849 		sock_set_reuseport(sock->sk);
1850 
1851 	err = xs_bind(transport, sock);
1852 	if (err) {
1853 		sock_release(sock);
1854 		goto out;
1855 	}
1856 
1857 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1858 	if (IS_ERR(filp))
1859 		return ERR_CAST(filp);
1860 	transport->file = filp;
1861 
1862 	return sock;
1863 out:
1864 	return ERR_PTR(err);
1865 }
1866 
1867 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1868 				      struct socket *sock)
1869 {
1870 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1871 									xprt);
1872 
1873 	if (!transport->inet) {
1874 		struct sock *sk = sock->sk;
1875 
1876 		lock_sock(sk);
1877 
1878 		xs_save_old_callbacks(transport, sk);
1879 
1880 		sk->sk_user_data = xprt;
1881 		sk->sk_data_ready = xs_data_ready;
1882 		sk->sk_write_space = xs_udp_write_space;
1883 		sk->sk_state_change = xs_local_state_change;
1884 		sk->sk_error_report = xs_error_report;
1885 
1886 		xprt_clear_connected(xprt);
1887 
1888 		/* Reset to new socket */
1889 		transport->sock = sock;
1890 		transport->inet = sk;
1891 
1892 		release_sock(sk);
1893 	}
1894 
1895 	xs_stream_start_connect(transport);
1896 
1897 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1898 }
1899 
1900 /**
1901  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1902  * @transport: socket transport to connect
1903  */
1904 static int xs_local_setup_socket(struct sock_xprt *transport)
1905 {
1906 	struct rpc_xprt *xprt = &transport->xprt;
1907 	struct file *filp;
1908 	struct socket *sock;
1909 	int status;
1910 
1911 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1912 					SOCK_STREAM, 0, &sock, 1);
1913 	if (status < 0) {
1914 		dprintk("RPC:       can't create AF_LOCAL "
1915 			"transport socket (%d).\n", -status);
1916 		goto out;
1917 	}
1918 	xs_reclassify_socket(AF_LOCAL, sock);
1919 
1920 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1921 	if (IS_ERR(filp)) {
1922 		status = PTR_ERR(filp);
1923 		goto out;
1924 	}
1925 	transport->file = filp;
1926 
1927 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1928 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1929 
1930 	status = xs_local_finish_connecting(xprt, sock);
1931 	trace_rpc_socket_connect(xprt, sock, status);
1932 	switch (status) {
1933 	case 0:
1934 		dprintk("RPC:       xprt %p connected to %s\n",
1935 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1936 		xprt->stat.connect_count++;
1937 		xprt->stat.connect_time += (long)jiffies -
1938 					   xprt->stat.connect_start;
1939 		xprt_set_connected(xprt);
1940 		break;
1941 	case -ENOBUFS:
1942 		break;
1943 	case -ENOENT:
1944 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1945 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1946 		break;
1947 	case -ECONNREFUSED:
1948 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1949 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1950 		break;
1951 	default:
1952 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1953 				__func__, -status,
1954 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1955 	}
1956 
1957 out:
1958 	xprt_clear_connecting(xprt);
1959 	xprt_wake_pending_tasks(xprt, status);
1960 	return status;
1961 }
1962 
1963 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1964 {
1965 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1966 	int ret;
1967 
1968 	if (transport->file)
1969 		goto force_disconnect;
1970 
1971 	if (RPC_IS_ASYNC(task)) {
1972 		/*
1973 		 * We want the AF_LOCAL connect to be resolved in the
1974 		 * filesystem namespace of the process making the rpc
1975 		 * call.  Thus we connect synchronously.
1976 		 *
1977 		 * If we want to support asynchronous AF_LOCAL calls,
1978 		 * we'll need to figure out how to pass a namespace to
1979 		 * connect.
1980 		 */
1981 		task->tk_rpc_status = -ENOTCONN;
1982 		rpc_exit(task, -ENOTCONN);
1983 		goto out_wake;
1984 	}
1985 	ret = xs_local_setup_socket(transport);
1986 	if (ret && !RPC_IS_SOFTCONN(task))
1987 		msleep_interruptible(15000);
1988 	return;
1989 force_disconnect:
1990 	xprt_force_disconnect(xprt);
1991 out_wake:
1992 	xprt_clear_connecting(xprt);
1993 	xprt_wake_pending_tasks(xprt, -ENOTCONN);
1994 }
1995 
1996 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
1997 /*
1998  * Note that this should be called with XPRT_LOCKED held, or recv_mutex
1999  * held, or when we otherwise know that we have exclusive access to the
2000  * socket, to guard against races with xs_reset_transport.
2001  */
2002 static void xs_set_memalloc(struct rpc_xprt *xprt)
2003 {
2004 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2005 			xprt);
2006 
2007 	/*
2008 	 * If there's no sock, then we have nothing to set. The
2009 	 * reconnecting process will get it for us.
2010 	 */
2011 	if (!transport->inet)
2012 		return;
2013 	if (atomic_read(&xprt->swapper))
2014 		sk_set_memalloc(transport->inet);
2015 }
2016 
2017 /**
2018  * xs_enable_swap - Tag this transport as being used for swap.
2019  * @xprt: transport to tag
2020  *
2021  * Take a reference to this transport on behalf of the rpc_clnt, and
2022  * optionally mark it for swapping if it wasn't already.
2023  */
2024 static int
2025 xs_enable_swap(struct rpc_xprt *xprt)
2026 {
2027 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2028 
2029 	mutex_lock(&xs->recv_mutex);
2030 	if (atomic_inc_return(&xprt->swapper) == 1 &&
2031 	    xs->inet)
2032 		sk_set_memalloc(xs->inet);
2033 	mutex_unlock(&xs->recv_mutex);
2034 	return 0;
2035 }
2036 
2037 /**
2038  * xs_disable_swap - Untag this transport as being used for swap.
2039  * @xprt: transport to tag
2040  *
2041  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2042  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2043  */
2044 static void
2045 xs_disable_swap(struct rpc_xprt *xprt)
2046 {
2047 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2048 
2049 	mutex_lock(&xs->recv_mutex);
2050 	if (atomic_dec_and_test(&xprt->swapper) &&
2051 	    xs->inet)
2052 		sk_clear_memalloc(xs->inet);
2053 	mutex_unlock(&xs->recv_mutex);
2054 }
2055 #else
2056 static void xs_set_memalloc(struct rpc_xprt *xprt)
2057 {
2058 }
2059 
2060 static int
2061 xs_enable_swap(struct rpc_xprt *xprt)
2062 {
2063 	return -EINVAL;
2064 }
2065 
2066 static void
2067 xs_disable_swap(struct rpc_xprt *xprt)
2068 {
2069 }
2070 #endif
2071 
2072 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2073 {
2074 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2075 
2076 	if (!transport->inet) {
2077 		struct sock *sk = sock->sk;
2078 
2079 		lock_sock(sk);
2080 
2081 		xs_save_old_callbacks(transport, sk);
2082 
2083 		sk->sk_user_data = xprt;
2084 		sk->sk_data_ready = xs_data_ready;
2085 		sk->sk_write_space = xs_udp_write_space;
2086 
2087 		xprt_set_connected(xprt);
2088 
2089 		/* Reset to new socket */
2090 		transport->sock = sock;
2091 		transport->inet = sk;
2092 
2093 		xs_set_memalloc(xprt);
2094 
2095 		release_sock(sk);
2096 	}
2097 	xs_udp_do_set_buffer_size(xprt);
2098 
2099 	xprt->stat.connect_start = jiffies;
2100 }
2101 
2102 static void xs_udp_setup_socket(struct work_struct *work)
2103 {
2104 	struct sock_xprt *transport =
2105 		container_of(work, struct sock_xprt, connect_worker.work);
2106 	struct rpc_xprt *xprt = &transport->xprt;
2107 	struct socket *sock;
2108 	int status = -EIO;
2109 	unsigned int pflags = current->flags;
2110 
2111 	if (atomic_read(&xprt->swapper))
2112 		current->flags |= PF_MEMALLOC;
2113 	sock = xs_create_sock(xprt, transport,
2114 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2115 			IPPROTO_UDP, false);
2116 	if (IS_ERR(sock))
2117 		goto out;
2118 
2119 	dprintk("RPC:       worker connecting xprt %p via %s to "
2120 				"%s (port %s)\n", xprt,
2121 			xprt->address_strings[RPC_DISPLAY_PROTO],
2122 			xprt->address_strings[RPC_DISPLAY_ADDR],
2123 			xprt->address_strings[RPC_DISPLAY_PORT]);
2124 
2125 	xs_udp_finish_connecting(xprt, sock);
2126 	trace_rpc_socket_connect(xprt, sock, 0);
2127 	status = 0;
2128 out:
2129 	xprt_clear_connecting(xprt);
2130 	xprt_unlock_connect(xprt, transport);
2131 	xprt_wake_pending_tasks(xprt, status);
2132 	current_restore_flags(pflags, PF_MEMALLOC);
2133 }
2134 
2135 /**
2136  * xs_tcp_shutdown - gracefully shut down a TCP socket
2137  * @xprt: transport
2138  *
2139  * Initiates a graceful shutdown of the TCP socket by calling the
2140  * equivalent of shutdown(SHUT_RDWR);
2141  */
2142 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2143 {
2144 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2145 	struct socket *sock = transport->sock;
2146 	int skst = transport->inet ? transport->inet->sk_state : TCP_CLOSE;
2147 
2148 	if (sock == NULL)
2149 		return;
2150 	if (!xprt->reuseport) {
2151 		xs_close(xprt);
2152 		return;
2153 	}
2154 	switch (skst) {
2155 	case TCP_FIN_WAIT1:
2156 	case TCP_FIN_WAIT2:
2157 		break;
2158 	case TCP_ESTABLISHED:
2159 	case TCP_CLOSE_WAIT:
2160 		kernel_sock_shutdown(sock, SHUT_RDWR);
2161 		trace_rpc_socket_shutdown(xprt, sock);
2162 		break;
2163 	default:
2164 		xs_reset_transport(transport);
2165 	}
2166 }
2167 
2168 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2169 		struct socket *sock)
2170 {
2171 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2172 	unsigned int keepidle;
2173 	unsigned int keepcnt;
2174 	unsigned int timeo;
2175 
2176 	spin_lock(&xprt->transport_lock);
2177 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2178 	keepcnt = xprt->timeout->to_retries + 1;
2179 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2180 		(xprt->timeout->to_retries + 1);
2181 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2182 	spin_unlock(&xprt->transport_lock);
2183 
2184 	/* TCP Keepalive options */
2185 	sock_set_keepalive(sock->sk);
2186 	tcp_sock_set_keepidle(sock->sk, keepidle);
2187 	tcp_sock_set_keepintvl(sock->sk, keepidle);
2188 	tcp_sock_set_keepcnt(sock->sk, keepcnt);
2189 
2190 	/* TCP user timeout (see RFC5482) */
2191 	tcp_sock_set_user_timeout(sock->sk, timeo);
2192 }
2193 
2194 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2195 		unsigned long connect_timeout,
2196 		unsigned long reconnect_timeout)
2197 {
2198 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2199 	struct rpc_timeout to;
2200 	unsigned long initval;
2201 
2202 	spin_lock(&xprt->transport_lock);
2203 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2204 		xprt->max_reconnect_timeout = reconnect_timeout;
2205 	if (connect_timeout < xprt->connect_timeout) {
2206 		memcpy(&to, xprt->timeout, sizeof(to));
2207 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2208 		/* Arbitrary lower limit */
2209 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2210 			initval = XS_TCP_INIT_REEST_TO << 1;
2211 		to.to_initval = initval;
2212 		to.to_maxval = initval;
2213 		memcpy(&transport->tcp_timeout, &to,
2214 				sizeof(transport->tcp_timeout));
2215 		xprt->timeout = &transport->tcp_timeout;
2216 		xprt->connect_timeout = connect_timeout;
2217 	}
2218 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2219 	spin_unlock(&xprt->transport_lock);
2220 }
2221 
2222 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2223 {
2224 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2225 
2226 	if (!transport->inet) {
2227 		struct sock *sk = sock->sk;
2228 
2229 		/* Avoid temporary address, they are bad for long-lived
2230 		 * connections such as NFS mounts.
2231 		 * RFC4941, section 3.6 suggests that:
2232 		 *    Individual applications, which have specific
2233 		 *    knowledge about the normal duration of connections,
2234 		 *    MAY override this as appropriate.
2235 		 */
2236 		if (xs_addr(xprt)->sa_family == PF_INET6) {
2237 			ip6_sock_set_addr_preferences(sk,
2238 				IPV6_PREFER_SRC_PUBLIC);
2239 		}
2240 
2241 		xs_tcp_set_socket_timeouts(xprt, sock);
2242 		tcp_sock_set_nodelay(sk);
2243 
2244 		lock_sock(sk);
2245 
2246 		xs_save_old_callbacks(transport, sk);
2247 
2248 		sk->sk_user_data = xprt;
2249 		sk->sk_data_ready = xs_data_ready;
2250 		sk->sk_state_change = xs_tcp_state_change;
2251 		sk->sk_write_space = xs_tcp_write_space;
2252 		sk->sk_error_report = xs_error_report;
2253 
2254 		/* socket options */
2255 		sock_reset_flag(sk, SOCK_LINGER);
2256 
2257 		xprt_clear_connected(xprt);
2258 
2259 		/* Reset to new socket */
2260 		transport->sock = sock;
2261 		transport->inet = sk;
2262 
2263 		release_sock(sk);
2264 	}
2265 
2266 	if (!xprt_bound(xprt))
2267 		return -ENOTCONN;
2268 
2269 	xs_set_memalloc(xprt);
2270 
2271 	xs_stream_start_connect(transport);
2272 
2273 	/* Tell the socket layer to start connecting... */
2274 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2275 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2276 }
2277 
2278 /**
2279  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2280  * @work: queued work item
2281  *
2282  * Invoked by a work queue tasklet.
2283  */
2284 static void xs_tcp_setup_socket(struct work_struct *work)
2285 {
2286 	struct sock_xprt *transport =
2287 		container_of(work, struct sock_xprt, connect_worker.work);
2288 	struct socket *sock = transport->sock;
2289 	struct rpc_xprt *xprt = &transport->xprt;
2290 	int status;
2291 	unsigned int pflags = current->flags;
2292 
2293 	if (atomic_read(&xprt->swapper))
2294 		current->flags |= PF_MEMALLOC;
2295 
2296 	if (xprt_connected(xprt))
2297 		goto out;
2298 	if (test_and_clear_bit(XPRT_SOCK_CONNECT_SENT,
2299 			       &transport->sock_state) ||
2300 	    !sock) {
2301 		xs_reset_transport(transport);
2302 		sock = xs_create_sock(xprt, transport, xs_addr(xprt)->sa_family,
2303 				      SOCK_STREAM, IPPROTO_TCP, true);
2304 		if (IS_ERR(sock)) {
2305 			xprt_wake_pending_tasks(xprt, PTR_ERR(sock));
2306 			goto out;
2307 		}
2308 	}
2309 
2310 	dprintk("RPC:       worker connecting xprt %p via %s to "
2311 				"%s (port %s)\n", xprt,
2312 			xprt->address_strings[RPC_DISPLAY_PROTO],
2313 			xprt->address_strings[RPC_DISPLAY_ADDR],
2314 			xprt->address_strings[RPC_DISPLAY_PORT]);
2315 
2316 	status = xs_tcp_finish_connecting(xprt, sock);
2317 	trace_rpc_socket_connect(xprt, sock, status);
2318 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2319 			xprt, -status, xprt_connected(xprt),
2320 			sock->sk->sk_state);
2321 	switch (status) {
2322 	case 0:
2323 	case -EINPROGRESS:
2324 		/* SYN_SENT! */
2325 		set_bit(XPRT_SOCK_CONNECT_SENT, &transport->sock_state);
2326 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2327 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2328 		fallthrough;
2329 	case -EALREADY:
2330 		goto out_unlock;
2331 	case -EADDRNOTAVAIL:
2332 		/* Source port number is unavailable. Try a new one! */
2333 		transport->srcport = 0;
2334 		status = -EAGAIN;
2335 		break;
2336 	case -EINVAL:
2337 		/* Happens, for instance, if the user specified a link
2338 		 * local IPv6 address without a scope-id.
2339 		 */
2340 	case -ECONNREFUSED:
2341 	case -ECONNRESET:
2342 	case -ENETDOWN:
2343 	case -ENETUNREACH:
2344 	case -EHOSTUNREACH:
2345 	case -EADDRINUSE:
2346 	case -ENOBUFS:
2347 		break;
2348 	default:
2349 		printk("%s: connect returned unhandled error %d\n",
2350 			__func__, status);
2351 		status = -EAGAIN;
2352 	}
2353 
2354 	/* xs_tcp_force_close() wakes tasks with a fixed error code.
2355 	 * We need to wake them first to ensure the correct error code.
2356 	 */
2357 	xprt_wake_pending_tasks(xprt, status);
2358 	xs_tcp_force_close(xprt);
2359 out:
2360 	xprt_clear_connecting(xprt);
2361 out_unlock:
2362 	xprt_unlock_connect(xprt, transport);
2363 	current_restore_flags(pflags, PF_MEMALLOC);
2364 }
2365 
2366 /**
2367  * xs_connect - connect a socket to a remote endpoint
2368  * @xprt: pointer to transport structure
2369  * @task: address of RPC task that manages state of connect request
2370  *
2371  * TCP: If the remote end dropped the connection, delay reconnecting.
2372  *
2373  * UDP socket connects are synchronous, but we use a work queue anyway
2374  * to guarantee that even unprivileged user processes can set up a
2375  * socket on a privileged port.
2376  *
2377  * If a UDP socket connect fails, the delay behavior here prevents
2378  * retry floods (hard mounts).
2379  */
2380 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2381 {
2382 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2383 	unsigned long delay = 0;
2384 
2385 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2386 
2387 	if (transport->sock != NULL) {
2388 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2389 			"seconds\n", xprt, xprt->reestablish_timeout / HZ);
2390 
2391 		delay = xprt_reconnect_delay(xprt);
2392 		xprt_reconnect_backoff(xprt, XS_TCP_INIT_REEST_TO);
2393 
2394 	} else
2395 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2396 
2397 	queue_delayed_work(xprtiod_workqueue,
2398 			&transport->connect_worker,
2399 			delay);
2400 }
2401 
2402 static void xs_wake_disconnect(struct sock_xprt *transport)
2403 {
2404 	if (test_and_clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state))
2405 		xs_tcp_force_close(&transport->xprt);
2406 }
2407 
2408 static void xs_wake_write(struct sock_xprt *transport)
2409 {
2410 	if (test_and_clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state))
2411 		xprt_write_space(&transport->xprt);
2412 }
2413 
2414 static void xs_wake_error(struct sock_xprt *transport)
2415 {
2416 	int sockerr;
2417 
2418 	if (!test_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2419 		return;
2420 	mutex_lock(&transport->recv_mutex);
2421 	if (transport->sock == NULL)
2422 		goto out;
2423 	if (!test_and_clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2424 		goto out;
2425 	sockerr = xchg(&transport->xprt_err, 0);
2426 	if (sockerr < 0)
2427 		xprt_wake_pending_tasks(&transport->xprt, sockerr);
2428 out:
2429 	mutex_unlock(&transport->recv_mutex);
2430 }
2431 
2432 static void xs_wake_pending(struct sock_xprt *transport)
2433 {
2434 	if (test_and_clear_bit(XPRT_SOCK_WAKE_PENDING, &transport->sock_state))
2435 		xprt_wake_pending_tasks(&transport->xprt, -EAGAIN);
2436 }
2437 
2438 static void xs_error_handle(struct work_struct *work)
2439 {
2440 	struct sock_xprt *transport = container_of(work,
2441 			struct sock_xprt, error_worker);
2442 
2443 	xs_wake_disconnect(transport);
2444 	xs_wake_write(transport);
2445 	xs_wake_error(transport);
2446 	xs_wake_pending(transport);
2447 }
2448 
2449 /**
2450  * xs_local_print_stats - display AF_LOCAL socket-specific stats
2451  * @xprt: rpc_xprt struct containing statistics
2452  * @seq: output file
2453  *
2454  */
2455 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2456 {
2457 	long idle_time = 0;
2458 
2459 	if (xprt_connected(xprt))
2460 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2461 
2462 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2463 			"%llu %llu %lu %llu %llu\n",
2464 			xprt->stat.bind_count,
2465 			xprt->stat.connect_count,
2466 			xprt->stat.connect_time / HZ,
2467 			idle_time,
2468 			xprt->stat.sends,
2469 			xprt->stat.recvs,
2470 			xprt->stat.bad_xids,
2471 			xprt->stat.req_u,
2472 			xprt->stat.bklog_u,
2473 			xprt->stat.max_slots,
2474 			xprt->stat.sending_u,
2475 			xprt->stat.pending_u);
2476 }
2477 
2478 /**
2479  * xs_udp_print_stats - display UDP socket-specific stats
2480  * @xprt: rpc_xprt struct containing statistics
2481  * @seq: output file
2482  *
2483  */
2484 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2485 {
2486 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2487 
2488 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2489 			"%lu %llu %llu\n",
2490 			transport->srcport,
2491 			xprt->stat.bind_count,
2492 			xprt->stat.sends,
2493 			xprt->stat.recvs,
2494 			xprt->stat.bad_xids,
2495 			xprt->stat.req_u,
2496 			xprt->stat.bklog_u,
2497 			xprt->stat.max_slots,
2498 			xprt->stat.sending_u,
2499 			xprt->stat.pending_u);
2500 }
2501 
2502 /**
2503  * xs_tcp_print_stats - display TCP socket-specific stats
2504  * @xprt: rpc_xprt struct containing statistics
2505  * @seq: output file
2506  *
2507  */
2508 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2509 {
2510 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2511 	long idle_time = 0;
2512 
2513 	if (xprt_connected(xprt))
2514 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2515 
2516 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2517 			"%llu %llu %lu %llu %llu\n",
2518 			transport->srcport,
2519 			xprt->stat.bind_count,
2520 			xprt->stat.connect_count,
2521 			xprt->stat.connect_time / HZ,
2522 			idle_time,
2523 			xprt->stat.sends,
2524 			xprt->stat.recvs,
2525 			xprt->stat.bad_xids,
2526 			xprt->stat.req_u,
2527 			xprt->stat.bklog_u,
2528 			xprt->stat.max_slots,
2529 			xprt->stat.sending_u,
2530 			xprt->stat.pending_u);
2531 }
2532 
2533 /*
2534  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2535  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2536  * to use the server side send routines.
2537  */
2538 static int bc_malloc(struct rpc_task *task)
2539 {
2540 	struct rpc_rqst *rqst = task->tk_rqstp;
2541 	size_t size = rqst->rq_callsize;
2542 	struct page *page;
2543 	struct rpc_buffer *buf;
2544 
2545 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2546 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2547 			  size);
2548 		return -EINVAL;
2549 	}
2550 
2551 	page = alloc_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
2552 	if (!page)
2553 		return -ENOMEM;
2554 
2555 	buf = page_address(page);
2556 	buf->len = PAGE_SIZE;
2557 
2558 	rqst->rq_buffer = buf->data;
2559 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2560 	return 0;
2561 }
2562 
2563 /*
2564  * Free the space allocated in the bc_alloc routine
2565  */
2566 static void bc_free(struct rpc_task *task)
2567 {
2568 	void *buffer = task->tk_rqstp->rq_buffer;
2569 	struct rpc_buffer *buf;
2570 
2571 	buf = container_of(buffer, struct rpc_buffer, data);
2572 	free_page((unsigned long)buf);
2573 }
2574 
2575 static int bc_sendto(struct rpc_rqst *req)
2576 {
2577 	struct xdr_buf *xdr = &req->rq_snd_buf;
2578 	struct sock_xprt *transport =
2579 			container_of(req->rq_xprt, struct sock_xprt, xprt);
2580 	struct msghdr msg = {
2581 		.msg_flags	= 0,
2582 	};
2583 	rpc_fraghdr marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT |
2584 					 (u32)xdr->len);
2585 	unsigned int sent = 0;
2586 	int err;
2587 
2588 	req->rq_xtime = ktime_get();
2589 	err = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
2590 	if (err < 0)
2591 		return err;
2592 	err = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, marker, &sent);
2593 	xdr_free_bvec(xdr);
2594 	if (err < 0 || sent != (xdr->len + sizeof(marker)))
2595 		return -EAGAIN;
2596 	return sent;
2597 }
2598 
2599 /**
2600  * bc_send_request - Send a backchannel Call on a TCP socket
2601  * @req: rpc_rqst containing Call message to be sent
2602  *
2603  * xpt_mutex ensures @rqstp's whole message is written to the socket
2604  * without interruption.
2605  *
2606  * Return values:
2607  *   %0 if the message was sent successfully
2608  *   %ENOTCONN if the message was not sent
2609  */
2610 static int bc_send_request(struct rpc_rqst *req)
2611 {
2612 	struct svc_xprt	*xprt;
2613 	int len;
2614 
2615 	/*
2616 	 * Get the server socket associated with this callback xprt
2617 	 */
2618 	xprt = req->rq_xprt->bc_xprt;
2619 
2620 	/*
2621 	 * Grab the mutex to serialize data as the connection is shared
2622 	 * with the fore channel
2623 	 */
2624 	mutex_lock(&xprt->xpt_mutex);
2625 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2626 		len = -ENOTCONN;
2627 	else
2628 		len = bc_sendto(req);
2629 	mutex_unlock(&xprt->xpt_mutex);
2630 
2631 	if (len > 0)
2632 		len = 0;
2633 
2634 	return len;
2635 }
2636 
2637 /*
2638  * The close routine. Since this is client initiated, we do nothing
2639  */
2640 
2641 static void bc_close(struct rpc_xprt *xprt)
2642 {
2643 	xprt_disconnect_done(xprt);
2644 }
2645 
2646 /*
2647  * The xprt destroy routine. Again, because this connection is client
2648  * initiated, we do nothing
2649  */
2650 
2651 static void bc_destroy(struct rpc_xprt *xprt)
2652 {
2653 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2654 
2655 	xs_xprt_free(xprt);
2656 	module_put(THIS_MODULE);
2657 }
2658 
2659 static const struct rpc_xprt_ops xs_local_ops = {
2660 	.reserve_xprt		= xprt_reserve_xprt,
2661 	.release_xprt		= xprt_release_xprt,
2662 	.alloc_slot		= xprt_alloc_slot,
2663 	.free_slot		= xprt_free_slot,
2664 	.rpcbind		= xs_local_rpcbind,
2665 	.set_port		= xs_local_set_port,
2666 	.connect		= xs_local_connect,
2667 	.buf_alloc		= rpc_malloc,
2668 	.buf_free		= rpc_free,
2669 	.prepare_request	= xs_stream_prepare_request,
2670 	.send_request		= xs_local_send_request,
2671 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2672 	.close			= xs_close,
2673 	.destroy		= xs_destroy,
2674 	.print_stats		= xs_local_print_stats,
2675 	.enable_swap		= xs_enable_swap,
2676 	.disable_swap		= xs_disable_swap,
2677 };
2678 
2679 static const struct rpc_xprt_ops xs_udp_ops = {
2680 	.set_buffer_size	= xs_udp_set_buffer_size,
2681 	.reserve_xprt		= xprt_reserve_xprt_cong,
2682 	.release_xprt		= xprt_release_xprt_cong,
2683 	.alloc_slot		= xprt_alloc_slot,
2684 	.free_slot		= xprt_free_slot,
2685 	.rpcbind		= rpcb_getport_async,
2686 	.set_port		= xs_set_port,
2687 	.connect		= xs_connect,
2688 	.get_srcaddr		= xs_sock_srcaddr,
2689 	.get_srcport		= xs_sock_srcport,
2690 	.buf_alloc		= rpc_malloc,
2691 	.buf_free		= rpc_free,
2692 	.send_request		= xs_udp_send_request,
2693 	.wait_for_reply_request	= xprt_wait_for_reply_request_rtt,
2694 	.timer			= xs_udp_timer,
2695 	.release_request	= xprt_release_rqst_cong,
2696 	.close			= xs_close,
2697 	.destroy		= xs_destroy,
2698 	.print_stats		= xs_udp_print_stats,
2699 	.enable_swap		= xs_enable_swap,
2700 	.disable_swap		= xs_disable_swap,
2701 	.inject_disconnect	= xs_inject_disconnect,
2702 };
2703 
2704 static const struct rpc_xprt_ops xs_tcp_ops = {
2705 	.reserve_xprt		= xprt_reserve_xprt,
2706 	.release_xprt		= xprt_release_xprt,
2707 	.alloc_slot		= xprt_alloc_slot,
2708 	.free_slot		= xprt_free_slot,
2709 	.rpcbind		= rpcb_getport_async,
2710 	.set_port		= xs_set_port,
2711 	.connect		= xs_connect,
2712 	.get_srcaddr		= xs_sock_srcaddr,
2713 	.get_srcport		= xs_sock_srcport,
2714 	.buf_alloc		= rpc_malloc,
2715 	.buf_free		= rpc_free,
2716 	.prepare_request	= xs_stream_prepare_request,
2717 	.send_request		= xs_tcp_send_request,
2718 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2719 	.close			= xs_tcp_shutdown,
2720 	.destroy		= xs_destroy,
2721 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2722 	.print_stats		= xs_tcp_print_stats,
2723 	.enable_swap		= xs_enable_swap,
2724 	.disable_swap		= xs_disable_swap,
2725 	.inject_disconnect	= xs_inject_disconnect,
2726 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2727 	.bc_setup		= xprt_setup_bc,
2728 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2729 	.bc_num_slots		= xprt_bc_max_slots,
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 	.wait_for_reply_request	= xprt_wait_for_reply_request_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->xprt_class = &xs_local_transport;
2849 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2850 
2851 	xprt->bind_timeout = XS_BIND_TO;
2852 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2853 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2854 
2855 	xprt->ops = &xs_local_ops;
2856 	xprt->timeout = &xs_local_default_timeout;
2857 
2858 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
2859 	INIT_WORK(&transport->error_worker, xs_error_handle);
2860 	INIT_DELAYED_WORK(&transport->connect_worker, xs_dummy_setup_socket);
2861 
2862 	switch (sun->sun_family) {
2863 	case AF_LOCAL:
2864 		if (sun->sun_path[0] != '/') {
2865 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2866 					sun->sun_path);
2867 			ret = ERR_PTR(-EINVAL);
2868 			goto out_err;
2869 		}
2870 		xprt_set_bound(xprt);
2871 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2872 		break;
2873 	default:
2874 		ret = ERR_PTR(-EAFNOSUPPORT);
2875 		goto out_err;
2876 	}
2877 
2878 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2879 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2880 
2881 	if (try_module_get(THIS_MODULE))
2882 		return xprt;
2883 	ret = ERR_PTR(-EINVAL);
2884 out_err:
2885 	xs_xprt_free(xprt);
2886 	return ret;
2887 }
2888 
2889 static const struct rpc_timeout xs_udp_default_timeout = {
2890 	.to_initval = 5 * HZ,
2891 	.to_maxval = 30 * HZ,
2892 	.to_increment = 5 * HZ,
2893 	.to_retries = 5,
2894 };
2895 
2896 /**
2897  * xs_setup_udp - Set up transport to use a UDP socket
2898  * @args: rpc transport creation arguments
2899  *
2900  */
2901 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2902 {
2903 	struct sockaddr *addr = args->dstaddr;
2904 	struct rpc_xprt *xprt;
2905 	struct sock_xprt *transport;
2906 	struct rpc_xprt *ret;
2907 
2908 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2909 			xprt_udp_slot_table_entries);
2910 	if (IS_ERR(xprt))
2911 		return xprt;
2912 	transport = container_of(xprt, struct sock_xprt, xprt);
2913 
2914 	xprt->prot = IPPROTO_UDP;
2915 	xprt->xprt_class = &xs_udp_transport;
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_WORK(&transport->error_worker, xs_error_handle);
2929 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
2930 
2931 	switch (addr->sa_family) {
2932 	case AF_INET:
2933 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2934 			xprt_set_bound(xprt);
2935 
2936 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2937 		break;
2938 	case AF_INET6:
2939 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2940 			xprt_set_bound(xprt);
2941 
2942 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2943 		break;
2944 	default:
2945 		ret = ERR_PTR(-EAFNOSUPPORT);
2946 		goto out_err;
2947 	}
2948 
2949 	if (xprt_bound(xprt))
2950 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2951 				xprt->address_strings[RPC_DISPLAY_ADDR],
2952 				xprt->address_strings[RPC_DISPLAY_PORT],
2953 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2954 	else
2955 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2956 				xprt->address_strings[RPC_DISPLAY_ADDR],
2957 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2958 
2959 	if (try_module_get(THIS_MODULE))
2960 		return xprt;
2961 	ret = ERR_PTR(-EINVAL);
2962 out_err:
2963 	xs_xprt_free(xprt);
2964 	return ret;
2965 }
2966 
2967 static const struct rpc_timeout xs_tcp_default_timeout = {
2968 	.to_initval = 60 * HZ,
2969 	.to_maxval = 60 * HZ,
2970 	.to_retries = 2,
2971 };
2972 
2973 /**
2974  * xs_setup_tcp - Set up transport to use a TCP socket
2975  * @args: rpc transport creation arguments
2976  *
2977  */
2978 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2979 {
2980 	struct sockaddr *addr = args->dstaddr;
2981 	struct rpc_xprt *xprt;
2982 	struct sock_xprt *transport;
2983 	struct rpc_xprt *ret;
2984 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
2985 
2986 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
2987 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
2988 
2989 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2990 			max_slot_table_size);
2991 	if (IS_ERR(xprt))
2992 		return xprt;
2993 	transport = container_of(xprt, struct sock_xprt, xprt);
2994 
2995 	xprt->prot = IPPROTO_TCP;
2996 	xprt->xprt_class = &xs_tcp_transport;
2997 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2998 
2999 	xprt->bind_timeout = XS_BIND_TO;
3000 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
3001 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3002 
3003 	xprt->ops = &xs_tcp_ops;
3004 	xprt->timeout = &xs_tcp_default_timeout;
3005 
3006 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3007 	xprt->connect_timeout = xprt->timeout->to_initval *
3008 		(xprt->timeout->to_retries + 1);
3009 
3010 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
3011 	INIT_WORK(&transport->error_worker, xs_error_handle);
3012 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3013 
3014 	switch (addr->sa_family) {
3015 	case AF_INET:
3016 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3017 			xprt_set_bound(xprt);
3018 
3019 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3020 		break;
3021 	case AF_INET6:
3022 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3023 			xprt_set_bound(xprt);
3024 
3025 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3026 		break;
3027 	default:
3028 		ret = ERR_PTR(-EAFNOSUPPORT);
3029 		goto out_err;
3030 	}
3031 
3032 	if (xprt_bound(xprt))
3033 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3034 				xprt->address_strings[RPC_DISPLAY_ADDR],
3035 				xprt->address_strings[RPC_DISPLAY_PORT],
3036 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3037 	else
3038 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3039 				xprt->address_strings[RPC_DISPLAY_ADDR],
3040 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3041 
3042 	if (try_module_get(THIS_MODULE))
3043 		return xprt;
3044 	ret = ERR_PTR(-EINVAL);
3045 out_err:
3046 	xs_xprt_free(xprt);
3047 	return ret;
3048 }
3049 
3050 /**
3051  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3052  * @args: rpc transport creation arguments
3053  *
3054  */
3055 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3056 {
3057 	struct sockaddr *addr = args->dstaddr;
3058 	struct rpc_xprt *xprt;
3059 	struct sock_xprt *transport;
3060 	struct svc_sock *bc_sock;
3061 	struct rpc_xprt *ret;
3062 
3063 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3064 			xprt_tcp_slot_table_entries);
3065 	if (IS_ERR(xprt))
3066 		return xprt;
3067 	transport = container_of(xprt, struct sock_xprt, xprt);
3068 
3069 	xprt->prot = IPPROTO_TCP;
3070 	xprt->xprt_class = &xs_bc_tcp_transport;
3071 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3072 	xprt->timeout = &xs_tcp_default_timeout;
3073 
3074 	/* backchannel */
3075 	xprt_set_bound(xprt);
3076 	xprt->bind_timeout = 0;
3077 	xprt->reestablish_timeout = 0;
3078 	xprt->idle_timeout = 0;
3079 
3080 	xprt->ops = &bc_tcp_ops;
3081 
3082 	switch (addr->sa_family) {
3083 	case AF_INET:
3084 		xs_format_peer_addresses(xprt, "tcp",
3085 					 RPCBIND_NETID_TCP);
3086 		break;
3087 	case AF_INET6:
3088 		xs_format_peer_addresses(xprt, "tcp",
3089 				   RPCBIND_NETID_TCP6);
3090 		break;
3091 	default:
3092 		ret = ERR_PTR(-EAFNOSUPPORT);
3093 		goto out_err;
3094 	}
3095 
3096 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3097 			xprt->address_strings[RPC_DISPLAY_ADDR],
3098 			xprt->address_strings[RPC_DISPLAY_PORT],
3099 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3100 
3101 	/*
3102 	 * Once we've associated a backchannel xprt with a connection,
3103 	 * we want to keep it around as long as the connection lasts,
3104 	 * in case we need to start using it for a backchannel again;
3105 	 * this reference won't be dropped until bc_xprt is destroyed.
3106 	 */
3107 	xprt_get(xprt);
3108 	args->bc_xprt->xpt_bc_xprt = xprt;
3109 	xprt->bc_xprt = args->bc_xprt;
3110 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3111 	transport->sock = bc_sock->sk_sock;
3112 	transport->inet = bc_sock->sk_sk;
3113 
3114 	/*
3115 	 * Since we don't want connections for the backchannel, we set
3116 	 * the xprt status to connected
3117 	 */
3118 	xprt_set_connected(xprt);
3119 
3120 	if (try_module_get(THIS_MODULE))
3121 		return xprt;
3122 
3123 	args->bc_xprt->xpt_bc_xprt = NULL;
3124 	args->bc_xprt->xpt_bc_xps = NULL;
3125 	xprt_put(xprt);
3126 	ret = ERR_PTR(-EINVAL);
3127 out_err:
3128 	xs_xprt_free(xprt);
3129 	return ret;
3130 }
3131 
3132 static struct xprt_class	xs_local_transport = {
3133 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3134 	.name		= "named UNIX socket",
3135 	.owner		= THIS_MODULE,
3136 	.ident		= XPRT_TRANSPORT_LOCAL,
3137 	.setup		= xs_setup_local,
3138 	.netid		= { "" },
3139 };
3140 
3141 static struct xprt_class	xs_udp_transport = {
3142 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3143 	.name		= "udp",
3144 	.owner		= THIS_MODULE,
3145 	.ident		= XPRT_TRANSPORT_UDP,
3146 	.setup		= xs_setup_udp,
3147 	.netid		= { "udp", "udp6", "" },
3148 };
3149 
3150 static struct xprt_class	xs_tcp_transport = {
3151 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3152 	.name		= "tcp",
3153 	.owner		= THIS_MODULE,
3154 	.ident		= XPRT_TRANSPORT_TCP,
3155 	.setup		= xs_setup_tcp,
3156 	.netid		= { "tcp", "tcp6", "" },
3157 };
3158 
3159 static struct xprt_class	xs_bc_tcp_transport = {
3160 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3161 	.name		= "tcp NFSv4.1 backchannel",
3162 	.owner		= THIS_MODULE,
3163 	.ident		= XPRT_TRANSPORT_BC_TCP,
3164 	.setup		= xs_setup_bc_tcp,
3165 	.netid		= { "" },
3166 };
3167 
3168 /**
3169  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3170  *
3171  */
3172 int init_socket_xprt(void)
3173 {
3174 	if (!sunrpc_table_header)
3175 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
3176 
3177 	xprt_register_transport(&xs_local_transport);
3178 	xprt_register_transport(&xs_udp_transport);
3179 	xprt_register_transport(&xs_tcp_transport);
3180 	xprt_register_transport(&xs_bc_tcp_transport);
3181 
3182 	return 0;
3183 }
3184 
3185 /**
3186  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3187  *
3188  */
3189 void cleanup_socket_xprt(void)
3190 {
3191 	if (sunrpc_table_header) {
3192 		unregister_sysctl_table(sunrpc_table_header);
3193 		sunrpc_table_header = NULL;
3194 	}
3195 
3196 	xprt_unregister_transport(&xs_local_transport);
3197 	xprt_unregister_transport(&xs_udp_transport);
3198 	xprt_unregister_transport(&xs_tcp_transport);
3199 	xprt_unregister_transport(&xs_bc_tcp_transport);
3200 }
3201 
3202 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3203 {
3204 	return param_set_uint_minmax(val, kp,
3205 			RPC_MIN_RESVPORT,
3206 			RPC_MAX_RESVPORT);
3207 }
3208 
3209 static const struct kernel_param_ops param_ops_portnr = {
3210 	.set = param_set_portnr,
3211 	.get = param_get_uint,
3212 };
3213 
3214 #define param_check_portnr(name, p) \
3215 	__param_check(name, p, unsigned int);
3216 
3217 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3218 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3219 
3220 static int param_set_slot_table_size(const char *val,
3221 				     const struct kernel_param *kp)
3222 {
3223 	return param_set_uint_minmax(val, kp,
3224 			RPC_MIN_SLOT_TABLE,
3225 			RPC_MAX_SLOT_TABLE);
3226 }
3227 
3228 static const struct kernel_param_ops param_ops_slot_table_size = {
3229 	.set = param_set_slot_table_size,
3230 	.get = param_get_uint,
3231 };
3232 
3233 #define param_check_slot_table_size(name, p) \
3234 	__param_check(name, p, unsigned int);
3235 
3236 static int param_set_max_slot_table_size(const char *val,
3237 				     const struct kernel_param *kp)
3238 {
3239 	return param_set_uint_minmax(val, kp,
3240 			RPC_MIN_SLOT_TABLE,
3241 			RPC_MAX_SLOT_TABLE_LIMIT);
3242 }
3243 
3244 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3245 	.set = param_set_max_slot_table_size,
3246 	.get = param_get_uint,
3247 };
3248 
3249 #define param_check_max_slot_table_size(name, p) \
3250 	__param_check(name, p, unsigned int);
3251 
3252 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3253 		   slot_table_size, 0644);
3254 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3255 		   max_slot_table_size, 0644);
3256 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3257 		   slot_table_size, 0644);
3258