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hc
2024-09-20 cf4ce59b3b70238352c7f1729f0f7223214828ad 
 kernel/net/sunrpc/svc_xprt.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * linux/net/sunrpc/svc_xprt.c
34  *
....@@ -34,7 +35,7 @@
3435 /* apparently the "standard" is that clients close
3536  * idle connections after 5 minutes, servers after
3637  * 6 minutes
37
- *   http://www.connectathon.org/talks96/nfstcp.pdf
38
+ *   http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
3839  */
3940 static int svc_conn_age_period = 6*60;
4041 
....@@ -145,12 +146,14 @@
145146 	struct module *owner = xprt->xpt_class->xcl_owner;
146147 	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
147148 		svcauth_unix_info_release(xprt);
149
+	put_cred(xprt->xpt_cred);
148150 	put_net(xprt->xpt_net);
149151 	/* See comment on corresponding get in xs_setup_bc_tcp(): */
150152 	if (xprt->xpt_bc_xprt)
151153 		xprt_put(xprt->xpt_bc_xprt);
152154 	if (xprt->xpt_bc_xps)
153155 		xprt_switch_put(xprt->xpt_bc_xps);
156
+	trace_svc_xprt_free(xprt);
154157 	xprt->xpt_ops->xpo_free(xprt);
155158 	module_put(owner);
156159 }
....@@ -180,7 +183,6 @@
180183 	mutex_init(&xprt->xpt_mutex);
181184 	spin_lock_init(&xprt->xpt_lock);
182185 	set_bit(XPT_BUSY, &xprt->xpt_flags);
183
-	rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
184186 	xprt->xpt_net = get_net(net);
185187 	strcpy(xprt->xpt_remotebuf, "uninitialized");
186188 }
....@@ -205,6 +207,7 @@
205207 		.sin6_port		= htons(port),
206208 	};
207209 #endif
210
+	struct svc_xprt *xprt;
208211 	struct sockaddr *sap;
209212 	size_t len;
210213 
....@@ -223,7 +226,11 @@
223226 		return ERR_PTR(-EAFNOSUPPORT);
224227 	}
225228 
226
-	return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
229
+	xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
230
+	if (IS_ERR(xprt))
231
+		trace_svc_xprt_create_err(serv->sv_program->pg_name,
232
+					  xcl->xcl_name, sap, xprt);
233
+	return xprt;
227234 }
228235 
229236 /*
....@@ -262,7 +269,8 @@
262269 
263270 static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
264271 			    struct net *net, const int family,
265
-			    const unsigned short port, int flags)
272
+			    const unsigned short port, int flags,
273
+			    const struct cred *cred)
266274 {
267275 	struct svc_xprt_class *xcl;
268276 
....@@ -283,6 +291,7 @@
283291 			module_put(xcl->xcl_owner);
284292 			return PTR_ERR(newxprt);
285293 		}
294
+		newxprt->xpt_cred = get_cred(cred);
286295 		svc_add_new_perm_xprt(serv, newxprt);
287296 		newport = svc_xprt_local_port(newxprt);
288297 		return newport;
....@@ -296,19 +305,16 @@
296305 
297306 int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
298307 		    struct net *net, const int family,
299
-		    const unsigned short port, int flags)
308
+		    const unsigned short port, int flags,
309
+		    const struct cred *cred)
300310 {
301311 	int err;
302312 
303
-	dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
304
-	err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
313
+	err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
305314 	if (err == -EPROTONOSUPPORT) {
306315 		request_module("svc%s", xprt_name);
307
-		err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
316
+		err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
308317 	}
309
-	if (err)
310
-		dprintk("svc: transport %s not found, err %d\n",
311
-			xprt_name, err);
312318 	return err;
313319 }
314320 EXPORT_SYMBOL_GPL(svc_create_xprt);
....@@ -367,15 +373,29 @@
367373 	struct svc_xprt	*xprt = rqstp->rq_xprt;
368374 	if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
369375 		atomic_dec(&xprt->xpt_nr_rqsts);
376
+		smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
370377 		svc_xprt_enqueue(xprt);
371378 	}
372379 }
373380 
374
-static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
381
+static bool svc_xprt_ready(struct svc_xprt *xprt)
375382 {
376
-	if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
383
+	unsigned long xpt_flags;
384
+
385
+	/*
386
+	 * If another cpu has recently updated xpt_flags,
387
+	 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
388
+	 * know about it; otherwise it's possible that both that cpu and
389
+	 * this one could call svc_xprt_enqueue() without either
390
+	 * svc_xprt_enqueue() recognizing that the conditions below
391
+	 * are satisfied, and we could stall indefinitely:
392
+	 */
393
+	smp_rmb();
394
+	xpt_flags = READ_ONCE(xprt->xpt_flags);
395
+
396
+	if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
377397 		return true;
378
-	if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) {
398
+	if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
379399 		if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
380400 		    svc_xprt_slots_in_range(xprt))
381401 			return true;
....@@ -391,7 +411,7 @@
391411 	struct svc_rqst	*rqstp = NULL;
392412 	int cpu;
393413 
394
-	if (!svc_xprt_has_something_to_do(xprt))
414
+	if (!svc_xprt_ready(xprt))
395415 		return;
396416 
397417 	/* Mark transport as busy. It will remain in this state until
....@@ -485,7 +505,7 @@
485505 	if (xprt && space < rqstp->rq_reserved) {
486506 		atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
487507 		rqstp->rq_reserved = space;
488
-
508
+		smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
489509 		svc_xprt_enqueue(xprt);
490510 	}
491511 }
....@@ -762,7 +782,6 @@
762782 	int len = 0;
763783 
764784 	if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
765
-		dprintk("svc_recv: found XPT_CLOSE\n");
766785 		if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
767786 			xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
768787 		svc_delete_xprt(xprt);
....@@ -778,9 +797,11 @@
778797 		__module_get(xprt->xpt_class->xcl_owner);
779798 		svc_check_conn_limits(xprt->xpt_server);
780799 		newxpt = xprt->xpt_ops->xpo_accept(xprt);
781
-		if (newxpt)
800
+		if (newxpt) {
801
+			newxpt->xpt_cred = get_cred(xprt->xpt_cred);
782802 			svc_add_new_temp_xprt(serv, newxpt);
783
-		else
803
+			trace_svc_xprt_accept(newxpt, serv->sv_name);
804
+		} else
784805 			module_put(xprt->xpt_class->xcl_owner);
785806 	} else if (svc_xprt_reserve_slot(rqstp, xprt)) {
786807 		/* XPT_DATA|XPT_DEFERRED case: */
....@@ -792,6 +813,8 @@
792813 			len = svc_deferred_recv(rqstp);
793814 		else
794815 			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
816
+		if (len > 0)
817
+			trace_svc_xdr_recvfrom(rqstp, &rqstp->rq_arg);
795818 		rqstp->rq_stime = ktime_get();
796819 		rqstp->rq_reserved = serv->sv_max_mesg;
797820 		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
....@@ -813,14 +836,6 @@
813836 	struct svc_xprt		*xprt = NULL;
814837 	struct svc_serv		*serv = rqstp->rq_server;
815838 	int			len, err;
816
-
817
-	dprintk("svc: server %p waiting for data (to = %ld)\n",
818
-		rqstp, timeout);
819
-
820
-	if (rqstp->rq_xprt)
821
-		printk(KERN_ERR
822
-			"svc_recv: service %p, transport not NULL!\n",
823
-			 rqstp);
824839 
825840 	err = svc_alloc_arg(rqstp);
826841 	if (err)
....@@ -869,7 +884,6 @@
869884 void svc_drop(struct svc_rqst *rqstp)
870885 {
871886 	trace_svc_drop(rqstp);
872
-	dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
873887 	svc_xprt_release(rqstp);
874888 }
875889 EXPORT_SYMBOL_GPL(svc_drop);
....@@ -892,17 +906,11 @@
892906 	xb->len = xb->head[0].iov_len +
893907 		xb->page_len +
894908 		xb->tail[0].iov_len;
895
-
896
-	/* Grab mutex to serialize outgoing data. */
897
-	mutex_lock(&xprt->xpt_mutex);
909
+	trace_svc_xdr_sendto(rqstp, xb);
898910 	trace_svc_stats_latency(rqstp);
899
-	if (test_bit(XPT_DEAD, &xprt->xpt_flags)
900
-			|| test_bit(XPT_CLOSE, &xprt->xpt_flags))
901
-		len = -ENOTCONN;
902
-	else
903
-		len = xprt->xpt_ops->xpo_sendto(rqstp);
904
-	mutex_unlock(&xprt->xpt_mutex);
905
-	rpc_wake_up(&xprt->xpt_bc_pending);
911
+
912
+	len = xprt->xpt_ops->xpo_sendto(rqstp);
913
+
906914 	trace_svc_send(rqstp, len);
907915 	svc_xprt_release(rqstp);
908916 
....@@ -1010,12 +1018,13 @@
10101018 	struct svc_serv	*serv = xprt->xpt_server;
10111019 	struct svc_deferred_req *dr;
10121020 
1013
-	/* Only do this once */
10141021 	if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1015
-		BUG();
1022
+		return;
10161023 
1017
-	dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1024
+	trace_svc_xprt_detach(xprt);
10181025 	xprt->xpt_ops->xpo_detach(xprt);
1026
+	if (xprt->xpt_bc_xprt)
1027
+		xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
10191028 
10201029 	spin_lock_bh(&serv->sv_lock);
10211030 	list_del_init(&xprt->xpt_list);
....@@ -1033,6 +1042,7 @@
10331042 
10341043 void svc_close_xprt(struct svc_xprt *xprt)
10351044 {
1045
+	trace_svc_xprt_close(xprt);
10361046 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
10371047 	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
10381048 		/* someone else will have to effect the close */
....@@ -1135,16 +1145,15 @@
11351145 	set_bit(XPT_DEFERRED, &xprt->xpt_flags);
11361146 	if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
11371147 		spin_unlock(&xprt->xpt_lock);
1138
-		dprintk("revisit canceled\n");
1148
+		trace_svc_defer_drop(dr);
11391149 		svc_xprt_put(xprt);
1140
-		trace_svc_drop_deferred(dr);
11411150 		kfree(dr);
11421151 		return;
11431152 	}
1144
-	dprintk("revisit queued\n");
11451153 	dr->xprt = NULL;
11461154 	list_add(&dr->handle.recent, &xprt->xpt_deferred);
11471155 	spin_unlock(&xprt->xpt_lock);
1156
+	trace_svc_defer_queue(dr);
11481157 	svc_xprt_enqueue(xprt);
11491158 	svc_xprt_put(xprt);
11501159 }
....@@ -1190,21 +1199,23 @@
11901199 		memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
11911200 		       dr->argslen << 2);
11921201 	}
1202
+	trace_svc_defer(rqstp);
11931203 	svc_xprt_get(rqstp->rq_xprt);
11941204 	dr->xprt = rqstp->rq_xprt;
11951205 	set_bit(RQ_DROPME, &rqstp->rq_flags);
11961206 
11971207 	dr->handle.revisit = svc_revisit;
1198
-	trace_svc_defer(rqstp);
11991208 	return &dr->handle;
12001209 }
12011210 
12021211 /*
12031212  * recv data from a deferred request into an active one
12041213  */
1205
-static int svc_deferred_recv(struct svc_rqst *rqstp)
1214
+static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
12061215 {
12071216 	struct svc_deferred_req *dr = rqstp->rq_deferred;
1217
+
1218
+	trace_svc_defer_recv(dr);
12081219 
12091220 	/* setup iov_base past transport header */
12101221 	rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
....@@ -1236,7 +1247,6 @@
12361247 				struct svc_deferred_req,
12371248 				handle.recent);
12381249 		list_del_init(&dr->handle.recent);
1239
-		trace_svc_revisit_deferred(dr);
12401250 	} else
12411251 		clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
12421252 	spin_unlock(&xprt->xpt_lock);