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authorTrond Myklebust <trond.myklebust@hammerspace.com>2018-09-03 23:39:27 -0400
committerTrond Myklebust <trond.myklebust@hammerspace.com>2018-09-30 15:35:15 -0400
commitc544577daddb618c7dd5fa7fb98d6a41782f020e (patch)
treeb3cfe2edc09c301ed6dfb4591e9d896c4965891f /net/sunrpc/xprt.c
parent36bd7de949f41d586ef7794169af75462b67acbc (diff)
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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 <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/xprt.c')
-rw-r--r--net/sunrpc/xprt.c77
1 files changed, 47 insertions, 30 deletions
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;
}