4 files changed, 27 insertions, 14 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index cff40aa7db62..bf8c49ff7530 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -114,6 +114,7 @@ struct rpc_xprt_ops {
         void            (*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
         int             (*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
         void            (*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
+        void            (*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
         void            (*rpcbind)(struct rpc_task *task);
         void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
         void            (*connect)(struct rpc_task *task);
@@ -281,6 +282,8 @@ void			xprt_connect(struct rpc_task *task);
 void                    xprt_reserve(struct rpc_task *task);
 int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
+void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
+void                    xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 int                     xprt_prepare_transmit(struct rpc_task *task);
 void                    xprt_transmit(struct rpc_task *task);
 void                    xprt_end_transmit(struct rpc_task *task);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a5a402a7d21f..5d7f61d7559c 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -969,11 +969,11 @@ static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
         return false;
 }
 
-static void xprt_alloc_slot(struct rpc_task *task)
+void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
 {
-        struct rpc_xprt *xprt = task->tk_xprt;
         struct rpc_rqst *req;
 
+        spin_lock(&xprt->reserve_lock);
         if (!list_empty(&xprt->free)) {
                 req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
                 list_del(&req->rq_list);
@@ -994,12 +994,29 @@ static void xprt_alloc_slot(struct rpc_task *task)
         default:
                 task->tk_status = -EAGAIN;
         }
+        spin_unlock(&xprt->reserve_lock);
         return;
 out_init_req:
         task->tk_status = 0;
         task->tk_rqstp = req;
         xprt_request_init(task, xprt);
+        spin_unlock(&xprt->reserve_lock);
+}
+EXPORT_SYMBOL_GPL(xprt_alloc_slot);
+
+void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+        /* Note: grabbing the xprt_lock_write() ensures that we throttle
+         * new slot allocation if the transport is congested (i.e. when
+         * reconnecting a stream transport or when out of socket write
+         * buffer space).
+         */
+        if (xprt_lock_write(xprt, task)) {
+                xprt_alloc_slot(xprt, task);
+                xprt_release_write(xprt, task);
+        }
 }
+EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot);
 
 static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 {
@@ -1083,20 +1100,9 @@ void xprt_reserve(struct rpc_task *task)
         if (task->tk_rqstp != NULL)
                 return;
 
-        /* Note: grabbing the xprt_lock_write() here is not strictly needed,
-         * but ensures that we throttle new slot allocation if the transport
-         * is congested (e.g. if reconnecting or if we're out of socket
-         * write buffer space).
-         */
         task->tk_timeout = 0;
         task->tk_status = -EAGAIN;
-        if (!xprt_lock_write(xprt, task))
-                return;
-
-        spin_lock(&xprt->reserve_lock);
-        xprt_alloc_slot(task);
-        spin_unlock(&xprt->reserve_lock);
-        xprt_release_write(xprt, task);
+        xprt->ops->alloc_slot(xprt, task);
 }
 
 static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 06cdbff79e4a..5d9202dc7cb1 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -713,6 +713,7 @@ static void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
 static struct rpc_xprt_ops xprt_rdma_procs = {
         .reserve_xprt           = xprt_rdma_reserve_xprt,
         .release_xprt           = xprt_release_xprt_cong, /* sunrpc/xprt.c */
+        .alloc_slot             = xprt_alloc_slot,
         .release_request        = xprt_release_rqst_cong,       /* ditto */
         .set_retrans_timeout    = xprt_set_retrans_timeout_def, /* ditto */
         .rpcbind                = rpcb_getport_async,   /* sunrpc/rpcb_clnt.c */
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 400567243f84..a35b8e52e551 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2473,6 +2473,7 @@ static void bc_destroy(struct rpc_xprt *xprt)
 static struct rpc_xprt_ops xs_local_ops = {
         .reserve_xprt           = xprt_reserve_xprt,
         .release_xprt           = xs_tcp_release_xprt,
+        .alloc_slot             = xprt_alloc_slot,
         .rpcbind                = xs_local_rpcbind,
         .set_port               = xs_local_set_port,
         .connect                = xs_connect,
@@ -2489,6 +2490,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
         .set_buffer_size        = xs_udp_set_buffer_size,
         .reserve_xprt           = xprt_reserve_xprt_cong,
         .release_xprt           = xprt_release_xprt_cong,
+        .alloc_slot             = xprt_alloc_slot,
         .rpcbind                = rpcb_getport_async,
         .set_port               = xs_set_port,
         .connect                = xs_connect,
@@ -2506,6 +2508,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
 static struct rpc_xprt_ops xs_tcp_ops = {
         .reserve_xprt           = xprt_reserve_xprt,
         .release_xprt           = xs_tcp_release_xprt,
+        .alloc_slot             = xprt_lock_and_alloc_slot,
         .rpcbind                = rpcb_getport_async,
         .set_port               = xs_set_port,
         .connect                = xs_connect,