From: Trond Myklebust Date: Tue, 6 Nov 2007 10:18:36 -0500 SUNRPC: Fix a race in xs_tcp_state_change() When scheduling the autoclose RPC call, we want to ensure that we don't race against the test_bit() call in xprt_clear_locked(). Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/xprt.c | 20 ++++++++++++++++++++ net/sunrpc/xprtsock.c | 5 +---- 3 files changed, 22 insertions(+), 4 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 30b17b3..6f524a9 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -246,6 +246,7 @@ struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid); void xprt_complete_rqst(struct rpc_task *task, int copied); void xprt_release_rqst_cong(struct rpc_task *task); void xprt_disconnect(struct rpc_xprt *xprt); +void xprt_force_disconnect(struct rpc_xprt *xprt); /* * Reserved bit positions in xprt->state diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index cd641c8..8575bf4 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -570,6 +570,7 @@ static void xprt_autoclose(struct work_struct *work) xprt_disconnect(xprt); xprt->ops->close(xprt); + clear_bit(XPRT_CLOSE_WAIT, &xprt->state); xprt_release_write(xprt, NULL); } @@ -588,6 +589,25 @@ void xprt_disconnect(struct rpc_xprt *xprt) } EXPORT_SYMBOL_GPL(xprt_disconnect); +/** + * xprt_force_disconnect - force a transport to disconnect + * @xprt: transport to disconnect + * + */ +void xprt_force_disconnect(struct rpc_xprt *xprt) +{ + /* Don't race with the test_bit() in xprt_clear_locked() */ + spin_lock_bh(&xprt->transport_lock); + set_bit(XPRT_CLOSE_WAIT, &xprt->state); + /* Try to schedule an autoclose RPC call */ + if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) + queue_work(rpciod_workqueue, &xprt->task_cleanup); + else if (xprt->snd_task != NULL) + rpc_wake_up_task(xprt->snd_task); + spin_unlock_bh(&xprt->transport_lock); +} +EXPORT_SYMBOL_GPL(xprt_force_disconnect); + static void xprt_init_autodisconnect(unsigned long data) { diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 2f630a5..29c5e6c 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1118,10 +1118,7 @@ static void xs_tcp_state_change(struct sock *sk) case TCP_SYN_RECV: break; case TCP_CLOSE_WAIT: - /* Try to schedule an autoclose RPC calls */ - set_bit(XPRT_CLOSE_WAIT, &xprt->state); - if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) - queue_work(rpciod_workqueue, &xprt->task_cleanup); + xprt_force_disconnect(xprt); default: xprt_disconnect(xprt); }