SUNRPC search xprt switch for sockaddr

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

include/linux/sunrpc/clnt.h

@@ -202,5 +202,7 @@ const char *rpc_proc_name(const struct rpc_task *task);
 
 void rpc_clnt_xprt_switch_put(struct rpc_clnt *);
 void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *, struct rpc_xprt *);
+bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
+			const struct sockaddr *sap);
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_CLNT_H */

include/linux/sunrpc/xprtmultipath.h

@@ -66,4 +66,6 @@ extern struct rpc_xprt *xprt_iter_xprt(struct rpc_xprt_iter *xpi);
 extern struct rpc_xprt *xprt_iter_get_xprt(struct rpc_xprt_iter *xpi);
 extern struct rpc_xprt *xprt_iter_get_next(struct rpc_xprt_iter *xpi);
 
+extern bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
+		const struct sockaddr *sap);
 #endif

net/sunrpc/clnt.c

@@ -2708,6 +2708,21 @@ void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
 }
 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_add_xprt);
 
+bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
+				   const struct sockaddr *sap)
+{
+	struct rpc_xprt_switch *xps;
+	bool ret;
+
+	xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
+
+	rcu_read_lock();
+	ret = rpc_xprt_switch_has_addr(xps, sap);
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_has_addr);
+
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 static void rpc_show_header(void)
 {

net/sunrpc/xprtmultipath.c

@@ -15,6 +15,7 @@
 #include <asm/cmpxchg.h>
 #include <linux/spinlock.h>
 #include <linux/sunrpc/xprt.h>
+#include <linux/sunrpc/addr.h>
 #include <linux/sunrpc/xprtmultipath.h>
 
 typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct list_head *head,
@@ -49,7 +50,8 @@ void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
 	if (xprt == NULL)
 		return;
 	spin_lock(&xps->xps_lock);
-	if (xps->xps_net == xprt->xprt_net || xps->xps_net == NULL)
+	if ((xps->xps_net == xprt->xprt_net || xps->xps_net == NULL) &&
+	    !rpc_xprt_switch_has_addr(xps, (struct sockaddr *)&xprt->addr))
 		xprt_switch_add_xprt_locked(xps, xprt);
 	spin_unlock(&xps->xps_lock);
 }
@@ -232,6 +234,26 @@ struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
 	return xprt_switch_find_current_entry(head, xpi->xpi_cursor);
 }
 
+bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
+			      const struct sockaddr *sap)
+{
+	struct list_head *head;
+	struct rpc_xprt *pos;
+
+	if (xps == NULL || sap == NULL)
+		return false;
+
+	head = &xps->xps_xprt_list;
+	list_for_each_entry_rcu(pos, head, xprt_switch) {
+		if (rpc_cmp_addr_port(sap, (struct sockaddr *)&pos->addr)) {
+			pr_info("RPC:   addr %s already in xprt switch\n",
+				pos->address_strings[RPC_DISPLAY_ADDR]);
+			return true;
+		}
+	}
+	return false;
+}
+
 static
 struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
 		const struct rpc_xprt *cur)