SUNRPC: Ensure we always bump the backlog queue in xprt_free_slot

Whenever we free a slot, we know that the resulting xprt->num_reqs will
be less than xprt->max_reqs, so we know that we can release at least one
backlogged rpc_task.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>=3.1]

1 files changed, 4 insertions, 6 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index f4385e45a5fc..c64c0ef519b5 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -995,13 +995,11 @@ out_init_req:
 
 static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 {
-        if (xprt_dynamic_free_slot(xprt, req))
-                return;
-
-        memset(req, 0, sizeof(*req));   /* mark unused */
-
         spin_lock(&xprt->reserve_lock);
-        list_add(&req->rq_list, &xprt->free);
+        if (!xprt_dynamic_free_slot(xprt, req)) {
+                memset(req, 0, sizeof(*req));   /* mark unused */
+                list_add(&req->rq_list, &xprt->free);
+        }
         rpc_wake_up_next(&xprt->backlog);
         spin_unlock(&xprt->reserve_lock);
 }