SUNRPC: Make rpc_clnt store the multipath iterators

This is a pre-patch for the RPC multipath code. It sets up the storage in
struct rpc_clnt for the multipath code.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

4 files changed, 35 insertions, 7 deletions

diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 0c5c2cbe96c9..1713e41d65ae 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -25,6 +25,7 @@
 #include <asm/signal.h>
 #include <linux/path.h>
 #include <net/ipv6.h>
+#include <linux/sunrpc/xprtmultipath.h>
 
 struct rpc_inode;
 
@@ -67,6 +68,7 @@ struct rpc_clnt {
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
         struct dentry           *cl_debugfs;    /* debugfs directory */
 #endif
+        struct rpc_xprt_iter    cl_xpi;
 };
 
 /*
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 799e65b944b9..3ce391cb80c4 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1181,12 +1181,12 @@ static struct rpc_auth *
 gss_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 {
         struct gss_auth *gss_auth;
-        struct rpc_xprt *xprt = rcu_access_pointer(clnt->cl_xprt);
+        struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 
         while (clnt != clnt->cl_parent) {
                 struct rpc_clnt *parent = clnt->cl_parent;
                 /* Find the original parent for this transport */
-                if (rcu_access_pointer(parent->cl_xprt) != xprt)
+                if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
                         break;
                 clnt = parent;
         }
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 2b4ad7aa40c6..625fb8a184c6 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -354,6 +354,7 @@ static void rpc_free_clid(struct rpc_clnt *clnt)
 }
 
 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
+                struct rpc_xprt_switch *xps,
                 struct rpc_xprt *xprt,
                 struct rpc_clnt *parent)
 {
@@ -411,6 +412,8 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
         }
 
         rpc_clnt_set_transport(clnt, xprt, timeout);
+        xprt_iter_init(&clnt->cl_xpi, xps);
+        xprt_switch_put(xps);
 
         clnt->cl_rtt = &clnt->cl_rtt_default;
         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
@@ -438,6 +441,7 @@ out_no_clid:
 out_err:
         rpciod_down();
 out_no_rpciod:
+        xprt_switch_put(xps);
         xprt_put(xprt);
         return ERR_PTR(err);
 }
@@ -446,8 +450,13 @@ struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
                                         struct rpc_xprt *xprt)
 {
         struct rpc_clnt *clnt = NULL;
+        struct rpc_xprt_switch *xps;
 
-        clnt = rpc_new_client(args, xprt, NULL);
+        xps = xprt_switch_alloc(xprt, GFP_KERNEL);
+        if (xps == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        clnt = rpc_new_client(args, xps, xprt, NULL);
         if (IS_ERR(clnt))
                 return clnt;
 
@@ -564,6 +573,7 @@ EXPORT_SYMBOL_GPL(rpc_create);
 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
                                            struct rpc_clnt *clnt)
 {
+        struct rpc_xprt_switch *xps;
         struct rpc_xprt *xprt;
         struct rpc_clnt *new;
         int err;
@@ -571,13 +581,17 @@ static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
         err = -ENOMEM;
         rcu_read_lock();
         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
+        xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
         rcu_read_unlock();
-        if (xprt == NULL)
+        if (xprt == NULL || xps == NULL) {
+                xprt_put(xprt);
+                xprt_switch_put(xps);
                 goto out_err;
+        }
         args->servername = xprt->servername;
         args->nodename = clnt->cl_nodename;
 
-        new = rpc_new_client(args, xprt, clnt);
+        new = rpc_new_client(args, xps, xprt, clnt);
         if (IS_ERR(new)) {
                 err = PTR_ERR(new);
                 goto out_err;
@@ -657,6 +671,7 @@ int rpc_switch_client_transport(struct rpc_clnt *clnt,
 {
         const struct rpc_timeout *old_timeo;
         rpc_authflavor_t pseudoflavor;
+        struct rpc_xprt_switch *xps, *oldxps;
         struct rpc_xprt *xprt, *old;
         struct rpc_clnt *parent;
         int err;
@@ -668,10 +683,17 @@ int rpc_switch_client_transport(struct rpc_clnt *clnt,
                 return PTR_ERR(xprt);
         }
 
+        xps = xprt_switch_alloc(xprt, GFP_KERNEL);
+        if (xps == NULL) {
+                xprt_put(xprt);
+                return -ENOMEM;
+        }
+
         pseudoflavor = clnt->cl_auth->au_flavor;
 
         old_timeo = clnt->cl_timeout;
         old = rpc_clnt_set_transport(clnt, xprt, timeout);
+        oldxps = xprt_iter_xchg_switch(&clnt->cl_xpi, xps);
 
         rpc_unregister_client(clnt);
         __rpc_clnt_remove_pipedir(clnt);
@@ -697,14 +719,17 @@ int rpc_switch_client_transport(struct rpc_clnt *clnt,
         synchronize_rcu();
         if (parent != clnt)
                 rpc_release_client(parent);
+        xprt_switch_put(oldxps);
         xprt_put(old);
         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
         return 0;
 
 out_revert:
+        xps = xprt_iter_xchg_switch(&clnt->cl_xpi, oldxps);
         rpc_clnt_set_transport(clnt, old, old_timeo);
         clnt->cl_parent = parent;
         rpc_client_register(clnt, pseudoflavor, NULL);
+        xprt_switch_put(xps);
         xprt_put(xprt);
         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
         return err;
@@ -783,6 +808,7 @@ rpc_free_client(struct rpc_clnt *clnt)
         rpc_free_iostats(clnt->cl_metrics);
         clnt->cl_metrics = NULL;
         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
+        xprt_iter_destroy(&clnt->cl_xpi);
         rpciod_down();
         rpc_free_clid(clnt);
         kfree(clnt);
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index cf5770d8f49a..44f025c150d8 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -648,10 +648,10 @@ static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbi
 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
 {
         struct rpc_clnt *parent = clnt->cl_parent;
-        struct rpc_xprt *xprt = rcu_dereference(clnt->cl_xprt);
+        struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 
         while (parent != clnt) {
-                if (rcu_dereference(parent->cl_xprt) != xprt)
+                if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
                         break;
                 if (clnt->cl_autobind)
                         break;