Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping"

This reverts commit 009a82f6437490c262584d65a14094a818bcb747.

The ability to optimise here relies on compiler being able to optimise
away tail calls to avoid stack overflows. Unfortunately, we are seeing
reports of problems, so let's just revert.

Reported-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index ec861cd0cfe8ce9fa5425909d243c660231f06c9..52d41d0c1ae1d54b6829a10134318ee2835b9fd5 100644 (file)
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -304,12 +304,4 @@ rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
 }
 #endif /* CONFIG_SUNRPC_SWAP */
 
-static inline bool
-rpc_task_need_resched(const struct rpc_task *task)
-{
-       if (RPC_IS_QUEUED(task) || task->tk_callback)
-               return true;
-       return false;
-}
-
 #endif /* _LINUX_SUNRPC_SCHED_H_ */

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 187d10443a1584e196245afc9837add06daa1c86..1d0395ef62c95b9285bdaca47f96f48a3d5093bf 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1540,7 +1540,6 @@ call_start(struct rpc_task *task)
        clnt->cl_stats->rpccnt++;
        task->tk_action = call_reserve;
        rpc_task_set_transport(task, clnt);
-       call_reserve(task);
 }
 
 /*
@@ -1554,9 +1553,6 @@ call_reserve(struct rpc_task *task)
        task->tk_status  = 0;
        task->tk_action  = call_reserveresult;
        xprt_reserve(task);
-       if (rpc_task_need_resched(task))
-               return;
-        call_reserveresult(task);
 }
 
 static void call_retry_reserve(struct rpc_task *task);
@@ -1579,7 +1575,6 @@ call_reserveresult(struct rpc_task *task)
        if (status >= 0) {
                if (task->tk_rqstp) {
                        task->tk_action = call_refresh;
-                       call_refresh(task);
                        return;
                }
 
@@ -1605,7 +1600,6 @@ call_reserveresult(struct rpc_task *task)
                /* fall through */
        case -EAGAIN:   /* woken up; retry */
                task->tk_action = call_retry_reserve;
-               call_retry_reserve(task);
                return;
        case -EIO:      /* probably a shutdown */
                break;
@@ -1628,9 +1622,6 @@ call_retry_reserve(struct rpc_task *task)
        task->tk_status  = 0;
        task->tk_action  = call_reserveresult;
        xprt_retry_reserve(task);
-       if (rpc_task_need_resched(task))
-               return;
-       call_reserveresult(task);
 }
 
 /*
@@ -1645,9 +1636,6 @@ call_refresh(struct rpc_task *task)
        task->tk_status = 0;
        task->tk_client->cl_stats->rpcauthrefresh++;
        rpcauth_refreshcred(task);
-       if (rpc_task_need_resched(task))
-               return;
-       call_refreshresult(task);
 }
 
 /*
@@ -1666,7 +1654,6 @@ call_refreshresult(struct rpc_task *task)
        case 0:
                if (rpcauth_uptodatecred(task)) {
                        task->tk_action = call_allocate;
-                       call_allocate(task);
                        return;
                }
                /* Use rate-limiting and a max number of retries if refresh
@@ -1685,7 +1672,6 @@ call_refreshresult(struct rpc_task *task)
                task->tk_cred_retry--;
                dprintk("RPC: %5u %s: retry refresh creds\n",
                                task->tk_pid, __func__);
-               call_refresh(task);
                return;
        }
        dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
@@ -1711,10 +1697,8 @@ call_allocate(struct rpc_task *task)
        task->tk_status = 0;
        task->tk_action = call_encode;
 
-       if (req->rq_buffer) {
-               call_encode(task);
+       if (req->rq_buffer)
                return;
-       }
 
        if (proc->p_proc != 0) {
                BUG_ON(proc->p_arglen == 0);
@@ -1740,12 +1724,8 @@ call_allocate(struct rpc_task *task)
 
        status = xprt->ops->buf_alloc(task);
        xprt_inject_disconnect(xprt);
-       if (status == 0) {
-               if (rpc_task_need_resched(task))
-                       return;
-               call_encode(task);
+       if (status == 0)
                return;
-       }
        if (status != -ENOMEM) {
                rpc_exit(task, status);
                return;
@@ -1828,8 +1808,12 @@ call_encode(struct rpc_task *task)
                xprt_request_enqueue_receive(task);
        xprt_request_enqueue_transmit(task);
 out:
-       task->tk_action = call_bind;
-       call_bind(task);
+       task->tk_action = call_transmit;
+       /* Check that the connection is OK */
+       if (!xprt_bound(task->tk_xprt))
+               task->tk_action = call_bind;
+       else if (!xprt_connected(task->tk_xprt))
+               task->tk_action = call_connect;
 }
 
 /*
@@ -1847,7 +1831,6 @@ rpc_task_handle_transmitted(struct rpc_task *task)
 {
        xprt_end_transmit(task);
        task->tk_action = call_transmit_status;
-       call_transmit_status(task);
 }
 
 /*
@@ -1865,7 +1848,6 @@ call_bind(struct rpc_task *task)
 
        if (xprt_bound(xprt)) {
                task->tk_action = call_connect;
-               call_connect(task);
                return;
        }
 
@@ -1896,7 +1878,6 @@ call_bind_status(struct rpc_task *task)
                dprint_status(task);
                task->tk_status = 0;
                task->tk_action = call_connect;
-               call_connect(task);
                return;
        }
 
@@ -1981,7 +1962,6 @@ call_connect(struct rpc_task *task)
 
        if (xprt_connected(xprt)) {
                task->tk_action = call_transmit;
-               call_transmit(task);
                return;
        }
 
@@ -2051,7 +2031,6 @@ call_connect_status(struct rpc_task *task)
        case 0:
                clnt->cl_stats->netreconn++;
                task->tk_action = call_transmit;
-               call_transmit(task);
                return;
        }
        rpc_exit(task, status);
@@ -2087,9 +2066,6 @@ call_transmit(struct rpc_task *task)
                xprt_transmit(task);
        }
        xprt_end_transmit(task);
-       if (rpc_task_need_resched(task))
-               return;
-       call_transmit_status(task);
 }
 
 /*
@@ -2107,9 +2083,6 @@ call_transmit_status(struct rpc_task *task)
        if (rpc_task_transmitted(task)) {
                if (task->tk_status == 0)
                        xprt_request_wait_receive(task);
-               if (rpc_task_need_resched(task))
-                       return;
-               call_status(task);
                return;
        }
 
@@ -2170,7 +2143,6 @@ call_bc_encode(struct rpc_task *task)
 {
        xprt_request_enqueue_transmit(task);
        task->tk_action = call_bc_transmit;
-       call_bc_transmit(task);
 }
 
 /*
@@ -2261,7 +2233,6 @@ call_status(struct rpc_task *task)
        status = task->tk_status;
        if (status >= 0) {
                task->tk_action = call_decode;
-               call_decode(task);
                return;
        }