From 7f3a1d1e1806a0eb9b200e3aed2a04431f2bcc6a Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 23 Aug 2018 00:03:43 -0400 Subject: [PATCH] SUNRPC: Refactor xprt_transmit() to remove wait for reply code Allow the caller in clnt.c to call into the code to wait for a reply after calling xprt_transmit(). Again, the reason is that the backchannel code does not need this functionality. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/clnt.c | 10 +---- net/sunrpc/xprt.c | 74 ++++++++++++++++++++++++++----------- 3 files changed, 54 insertions(+), 31 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 0250294c904a..4fa2af087cff 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -335,6 +335,7 @@ void xprt_free_slot(struct rpc_xprt *xprt, void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task); bool xprt_prepare_transmit(struct rpc_task *task); void xprt_request_enqueue_receive(struct rpc_task *task); +void xprt_request_wait_receive(struct rpc_task *task); void xprt_transmit(struct rpc_task *task); void xprt_end_transmit(struct rpc_task *task); int xprt_adjust_timeout(struct rpc_rqst *req); diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 414966273a3f..775d6e80b6e8 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1975,15 +1975,6 @@ call_transmit(struct rpc_task *task) return; if (is_retrans) task->tk_client->cl_stats->rpcretrans++; - /* - * On success, ensure that we call xprt_end_transmit() before sleeping - * in order to allow access to the socket to other RPC requests. - */ - call_transmit_status(task); - if (rpc_reply_expected(task)) - return; - task->tk_action = rpc_exit_task; - rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task); } /* @@ -2000,6 +1991,7 @@ call_transmit_status(struct rpc_task *task) */ if (task->tk_status == 0) { xprt_end_transmit(task); + xprt_request_wait_receive(task); return; } diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 2ae0a4c47d59..a6a33c178870 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -654,6 +654,22 @@ void xprt_force_disconnect(struct rpc_xprt *xprt) } EXPORT_SYMBOL_GPL(xprt_force_disconnect); +static unsigned int +xprt_connect_cookie(struct rpc_xprt *xprt) +{ + return READ_ONCE(xprt->connect_cookie); +} + +static bool +xprt_request_retransmit_after_disconnect(struct rpc_task *task) +{ + struct rpc_rqst *req = task->tk_rqstp; + struct rpc_xprt *xprt = req->rq_xprt; + + return req->rq_connect_cookie != xprt_connect_cookie(xprt) || + !xprt_connected(xprt); +} + /** * xprt_conditional_disconnect - force a transport to disconnect * @xprt: transport to disconnect @@ -1009,6 +1025,39 @@ static void xprt_timer(struct rpc_task *task) task->tk_status = 0; } +/** + * xprt_request_wait_receive - wait for the reply to an RPC request + * @task: RPC task about to send a request + * + */ +void xprt_request_wait_receive(struct rpc_task *task) +{ + struct rpc_rqst *req = task->tk_rqstp; + struct rpc_xprt *xprt = req->rq_xprt; + + if (!test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate)) + return; + /* + * Sleep on the pending queue if we're expecting a reply. + * The spinlock ensures atomicity between the test of + * req->rq_reply_bytes_recvd, and the call to rpc_sleep_on(). + */ + spin_lock(&xprt->queue_lock); + if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate)) { + xprt->ops->set_retrans_timeout(task); + rpc_sleep_on(&xprt->pending, task, xprt_timer); + /* + * Send an extra queue wakeup call if the + * connection was dropped in case the call to + * rpc_sleep_on() raced. + */ + if (xprt_request_retransmit_after_disconnect(task)) + rpc_wake_up_queued_task_set_status(&xprt->pending, + task, -ENOTCONN); + } + spin_unlock(&xprt->queue_lock); +} + /** * xprt_prepare_transmit - reserve the transport before sending a request * @task: RPC task about to send a request @@ -1028,9 +1077,8 @@ bool xprt_prepare_transmit(struct rpc_task *task) task->tk_status = req->rq_reply_bytes_recvd; goto out_unlock; } - if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) - && xprt_connected(xprt) - && req->rq_connect_cookie == xprt->connect_cookie) { + if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) && + !xprt_request_retransmit_after_disconnect(task)) { xprt->ops->set_retrans_timeout(task); rpc_sleep_on(&xprt->pending, task, xprt_timer); goto out_unlock; @@ -1091,8 +1139,6 @@ void xprt_transmit(struct rpc_task *task) task->tk_flags |= RPC_TASK_SENT; spin_lock_bh(&xprt->transport_lock); - xprt->ops->set_retrans_timeout(task); - xprt->stat.sends++; xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; xprt->stat.bklog_u += xprt->backlog.qlen; @@ -1101,22 +1147,6 @@ void xprt_transmit(struct rpc_task *task) spin_unlock_bh(&xprt->transport_lock); req->rq_connect_cookie = connect_cookie; - if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate)) { - /* - * Sleep on the pending queue if we're expecting a reply. - * The spinlock ensures atomicity between the test of - * req->rq_reply_bytes_recvd, and the call to rpc_sleep_on(). - */ - spin_lock(&xprt->queue_lock); - if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate)) { - rpc_sleep_on(&xprt->pending, task, xprt_timer); - /* Wake up immediately if the connection was dropped */ - if (!xprt_connected(xprt)) - rpc_wake_up_queued_task_set_status(&xprt->pending, - task, -ENOTCONN); - } - spin_unlock(&xprt->queue_lock); - } } static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task) @@ -1321,7 +1351,7 @@ xprt_request_init(struct rpc_task *task) req->rq_xprt = xprt; req->rq_buffer = NULL; req->rq_xid = xprt_alloc_xid(xprt); - req->rq_connect_cookie = xprt->connect_cookie - 1; + req->rq_connect_cookie = xprt_connect_cookie(xprt) - 1; req->rq_bytes_sent = 0; req->rq_snd_buf.len = 0; req->rq_snd_buf.buflen = 0;