SUNRPC: Add a ->free_slot transport callout

Refactor: xprtrdma needs to have better control over when RPCs are
awoken from the backlog queue, so replace xprt_free_slot with a
transport op callout.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

5 files changed, 13 insertions, 2 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 9784e2875e7e..706eef12bbc0 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -127,6 +127,8 @@ struct rpc_xprt_ops {
         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            (*free_slot)(struct rpc_xprt *xprt,
+                                     struct rpc_rqst *req);
         void            (*rpcbind)(struct rpc_task *task);
         void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
         void            (*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
@@ -329,6 +331,8 @@ void			xprt_retry_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_free_slot(struct rpc_xprt *xprt,
+                                       struct rpc_rqst *req);
 void                    xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 bool                    xprt_prepare_transmit(struct rpc_task *task);
 void                    xprt_transmit(struct rpc_task *task);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 2d959268d9b7..3c85af058227 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1186,7 +1186,7 @@ void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
 }
 EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot);
 
-static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
+void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 {
         spin_lock(&xprt->reserve_lock);
         if (!xprt_dynamic_free_slot(xprt, req)) {
@@ -1196,6 +1196,7 @@ static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
         xprt_wake_up_backlog(xprt);
         spin_unlock(&xprt->reserve_lock);
 }
+EXPORT_SYMBOL_GPL(xprt_free_slot);
 
 static void xprt_free_all_slots(struct rpc_xprt *xprt)
 {
@@ -1375,7 +1376,7 @@ void xprt_release(struct rpc_task *task)
 
         dprintk("RPC: %5u release request %p\n", task->tk_pid, req);
         if (likely(!bc_prealloc(req)))
-                xprt_free_slot(xprt, req);
+                xprt->ops->free_slot(xprt, req);
         else
                 xprt_free_bc_request(req);
 }
diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index a73632ca9048..1035516d54e2 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -273,6 +273,7 @@ static const struct rpc_xprt_ops xprt_rdma_bc_procs = {
         .reserve_xprt           = xprt_reserve_xprt_cong,
         .release_xprt           = xprt_release_xprt_cong,
         .alloc_slot             = xprt_alloc_slot,
+        .free_slot              = xprt_free_slot,
         .release_request        = xprt_release_rqst_cong,
         .buf_alloc              = xprt_rdma_bc_allocate,
         .buf_free               = xprt_rdma_bc_free,
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 4717578b4b81..cf5e866ee969 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -781,6 +781,7 @@ static const struct rpc_xprt_ops xprt_rdma_procs = {
         .reserve_xprt           = xprt_reserve_xprt_cong,
         .release_xprt           = xprt_release_xprt_cong, /* sunrpc/xprt.c */
         .alloc_slot             = xprt_alloc_slot,
+        .free_slot              = xprt_free_slot,
         .release_request        = xprt_release_rqst_cong,       /* ditto */
         .set_retrans_timeout    = xprt_set_retrans_timeout_def, /* ditto */
         .timer                  = xprt_rdma_timer,
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index c8902f11efdd..9e1c5024aba9 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2763,6 +2763,7 @@ static const struct rpc_xprt_ops xs_local_ops = {
         .reserve_xprt           = xprt_reserve_xprt,
         .release_xprt           = xs_tcp_release_xprt,
         .alloc_slot             = xprt_alloc_slot,
+        .free_slot              = xprt_free_slot,
         .rpcbind                = xs_local_rpcbind,
         .set_port               = xs_local_set_port,
         .connect                = xs_local_connect,
@@ -2782,6 +2783,7 @@ static const struct rpc_xprt_ops xs_udp_ops = {
         .reserve_xprt           = xprt_reserve_xprt_cong,
         .release_xprt           = xprt_release_xprt_cong,
         .alloc_slot             = xprt_alloc_slot,
+        .free_slot              = xprt_free_slot,
         .rpcbind                = rpcb_getport_async,
         .set_port               = xs_set_port,
         .connect                = xs_connect,
@@ -2803,6 +2805,7 @@ static const 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,
+        .free_slot              = xprt_free_slot,
         .rpcbind                = rpcb_getport_async,
         .set_port               = xs_set_port,
         .connect                = xs_connect,
@@ -2834,6 +2837,7 @@ static const struct rpc_xprt_ops bc_tcp_ops = {
         .reserve_xprt           = xprt_reserve_xprt,
         .release_xprt           = xprt_release_xprt,
         .alloc_slot             = xprt_alloc_slot,
+        .free_slot              = xprt_free_slot,
         .buf_alloc              = bc_malloc,
         .buf_free               = bc_free,
         .send_request           = bc_send_request,