Commit 8593e010 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

SUNRPC: Fix congestion window race with disconnect 



If the congestion window closes just as the transport disconnects,
a reconnect is never driven because:

1. The XPRT_CONG_WAIT flag prevents tasks from taking the write lock
2. There's no wake-up of the first task on the xprt->sending queue

To address this, clear the congestion wait flag as part of
completing a disconnect.

Fixes: 75891f50 ("SUNRPC: Support for congestion control ... ")
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 9ba82886

net/sunrpc/xprt.c

+7 −0
Original line number Diff line number Diff line
@@ -456,6 +456,12 @@ void xprt_release_rqst_cong(struct rpc_task *task) 
}

EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);



static void xprt_clear_congestion_window_wait_locked(struct rpc_xprt *xprt)

{

	if (test_and_clear_bit(XPRT_CWND_WAIT, &xprt->state))

		__xprt_lock_write_next_cong(xprt);

}



/*

 * Clear the congestion window wait flag and wake up the next

 * entry on xprt->sending
@@ -671,6 +677,7 @@ void xprt_disconnect_done(struct rpc_xprt *xprt) 
	spin_lock(&xprt->transport_lock);

	xprt_clear_connected(xprt);

	xprt_clear_write_space_locked(xprt);

	xprt_clear_congestion_window_wait_locked(xprt);

	xprt_wake_pending_tasks(xprt, -ENOTCONN);

	spin_unlock(&xprt->transport_lock);

}