rpc: share one xps between all backchannels
The spec allows backchannels for multiple clients to share the same tcp
connection. When that happens, we need to use the same xprt for all of
them. Similarly, we need the same xps.
This fixes list corruption introduced by the multipath code.
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index b33721d..2808d55 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -452,10 +452,20 @@
struct rpc_clnt *clnt = NULL;
struct rpc_xprt_switch *xps;
- xps = xprt_switch_alloc(xprt, GFP_KERNEL);
- if (xps == NULL) {
- xprt_put(xprt);
- return ERR_PTR(-ENOMEM);
+ if (args->bc_xprt && args->bc_xprt->xpt_bc_xps) {
+ WARN_ON(args->protocol != XPRT_TRANSPORT_BC_TCP);
+ xps = args->bc_xprt->xpt_bc_xps;
+ xprt_switch_get(xps);
+ } else {
+ xps = xprt_switch_alloc(xprt, GFP_KERNEL);
+ if (xps == NULL) {
+ xprt_put(xprt);
+ return ERR_PTR(-ENOMEM);
+ }
+ if (xprt->bc_xprt) {
+ xprt_switch_get(xps);
+ xprt->bc_xprt->xpt_bc_xps = xps;
+ }
}
clnt = rpc_new_client(args, xps, xprt, NULL);
if (IS_ERR(clnt))
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index f5572e31..4f01f63 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -136,6 +136,8 @@
/* See comment on corresponding get in xs_setup_bc_tcp(): */
if (xprt->xpt_bc_xprt)
xprt_put(xprt->xpt_bc_xprt);
+ if (xprt->xpt_bc_xps)
+ xprt_switch_put(xprt->xpt_bc_xps);
xprt->xpt_ops->xpo_free(xprt);
module_put(owner);
}
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 2d3e0c4..7e2b2fa 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -3057,6 +3057,7 @@
return xprt;
args->bc_xprt->xpt_bc_xprt = NULL;
+ args->bc_xprt->xpt_bc_xps = NULL;
xprt_put(xprt);
ret = ERR_PTR(-EINVAL);
out_err: