From c544577daddb618c7dd5fa7fb98d6a41782f020e Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 3 Sep 2018 23:39:27 -0400 Subject: SUNRPC: Clean up transport write space handling Treat socket write space handling in the same way we now treat transport congestion: by denying the XPRT_LOCK until the transport signals that it has free buffer space. Signed-off-by: Trond Myklebust --- net/sunrpc/xprt.c | 77 +++++++++++++++++++++++++++++++++---------------------- 1 file changed, 47 insertions(+), 30 deletions(-) (limited to 'net/sunrpc/xprt.c') diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 849e102e3c5a..55dc5c7069b9 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -169,6 +169,17 @@ out: } EXPORT_SYMBOL_GPL(xprt_load_transport); +static void xprt_clear_locked(struct rpc_xprt *xprt) +{ + xprt->snd_task = NULL; + if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state)) { + smp_mb__before_atomic(); + clear_bit(XPRT_LOCKED, &xprt->state); + smp_mb__after_atomic(); + } else + queue_work(xprtiod_workqueue, &xprt->task_cleanup); +} + /** * xprt_reserve_xprt - serialize write access to transports * @task: task that is requesting access to the transport @@ -188,10 +199,14 @@ int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task) return 1; goto out_sleep; } + if (test_bit(XPRT_WRITE_SPACE, &xprt->state)) + goto out_unlock; xprt->snd_task = task; return 1; +out_unlock: + xprt_clear_locked(xprt); out_sleep: dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); @@ -208,17 +223,6 @@ out_sleep: } EXPORT_SYMBOL_GPL(xprt_reserve_xprt); -static void xprt_clear_locked(struct rpc_xprt *xprt) -{ - xprt->snd_task = NULL; - if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state)) { - smp_mb__before_atomic(); - clear_bit(XPRT_LOCKED, &xprt->state); - smp_mb__after_atomic(); - } else - queue_work(xprtiod_workqueue, &xprt->task_cleanup); -} - static bool xprt_need_congestion_window_wait(struct rpc_xprt *xprt) { @@ -267,10 +271,13 @@ int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) xprt->snd_task = task; return 1; } + if (test_bit(XPRT_WRITE_SPACE, &xprt->state)) + goto out_unlock; if (!xprt_need_congestion_window_wait(xprt)) { xprt->snd_task = task; return 1; } +out_unlock: xprt_clear_locked(xprt); out_sleep: dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); @@ -309,10 +316,12 @@ static void __xprt_lock_write_next(struct rpc_xprt *xprt) { if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) return; - + if (test_bit(XPRT_WRITE_SPACE, &xprt->state)) + goto out_unlock; if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending, __xprt_lock_write_func, xprt)) return; +out_unlock: xprt_clear_locked(xprt); } @@ -320,6 +329,8 @@ static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) { if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) return; + if (test_bit(XPRT_WRITE_SPACE, &xprt->state)) + goto out_unlock; if (xprt_need_congestion_window_wait(xprt)) goto out_unlock; if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending, @@ -510,39 +521,46 @@ EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks); /** * xprt_wait_for_buffer_space - wait for transport output buffer to clear - * @task: task to be put to sleep - * @action: function pointer to be executed after wait + * @xprt: transport * * Note that we only set the timer for the case of RPC_IS_SOFT(), since * we don't in general want to force a socket disconnection due to * an incomplete RPC call transmission. */ -void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action) +void xprt_wait_for_buffer_space(struct rpc_xprt *xprt) { - struct rpc_rqst *req = task->tk_rqstp; - struct rpc_xprt *xprt = req->rq_xprt; - - task->tk_timeout = RPC_IS_SOFT(task) ? req->rq_timeout : 0; - rpc_sleep_on(&xprt->pending, task, action); + set_bit(XPRT_WRITE_SPACE, &xprt->state); } EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space); +static bool +xprt_clear_write_space_locked(struct rpc_xprt *xprt) +{ + if (test_and_clear_bit(XPRT_WRITE_SPACE, &xprt->state)) { + __xprt_lock_write_next(xprt); + dprintk("RPC: write space: waking waiting task on " + "xprt %p\n", xprt); + return true; + } + return false; +} + /** * xprt_write_space - wake the task waiting for transport output buffer space * @xprt: transport with waiting tasks * * Can be called in a soft IRQ context, so xprt_write_space never sleeps. */ -void xprt_write_space(struct rpc_xprt *xprt) +bool xprt_write_space(struct rpc_xprt *xprt) { + bool ret; + + if (!test_bit(XPRT_WRITE_SPACE, &xprt->state)) + return false; spin_lock_bh(&xprt->transport_lock); - if (xprt->snd_task) { - dprintk("RPC: write space: waking waiting task on " - "xprt %p\n", xprt); - rpc_wake_up_queued_task_on_wq(xprtiod_workqueue, - &xprt->pending, xprt->snd_task); - } + ret = xprt_clear_write_space_locked(xprt); spin_unlock_bh(&xprt->transport_lock); + return ret; } EXPORT_SYMBOL_GPL(xprt_write_space); @@ -653,6 +671,7 @@ void xprt_disconnect_done(struct rpc_xprt *xprt) dprintk("RPC: disconnected transport %p\n", xprt); spin_lock_bh(&xprt->transport_lock); xprt_clear_connected(xprt); + xprt_clear_write_space_locked(xprt); xprt_wake_pending_tasks(xprt, -EAGAIN); spin_unlock_bh(&xprt->transport_lock); } @@ -1326,9 +1345,7 @@ xprt_transmit(struct rpc_task *task) if (!xprt_request_data_received(task) || test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) continue; - } else if (!test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) - rpc_wake_up_queued_task(&xprt->pending, task); - else + } else if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) task->tk_status = status; break; } -- cgit v1.2.3