Commit b977b644 authored Feb 08, 2017 by Chuck Lever Committed by Anna Schumaker Feb 10, 2017

sunrpc: Allow xprt->ops->timer method to sleep



The transport lock is needed to protect the xprt_adjust_cwnd() call
in xs_udp_timer, but it is not necessary for accessing the
rq_reply_bytes_recvd or tk_status fields. It is correct to sublimate
the lock into UDP's xs_udp_timer method, where it is required.

The ->timer method has to take the transport lock if needed, but it
can now sleep safely, or even call back into the RPC scheduler.

This is more a clean-up than a fix, but the "issue" was introduced
by my transport switch patches back in 2005.

Fixes: 46c0ee8b ("RPC: separate xprt_timer implementations")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

parent 9a5c63e9

net/sunrpc/xprt.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -897,13 +897,11 @@ static void xprt_timer(struct rpc_task *task)
		return;
		dprintk("RPC: %5u xprt_timer\n", task->tk_pid);

		spin_lock_bh(&xprt->transport_lock);
		if (!req->rq_reply_bytes_recvd) {
		if (xprt->ops->timer)
		xprt->ops->timer(xprt, task);
		} else
		task->tk_status = 0;
		spin_unlock_bh(&xprt->transport_lock);
		}

		/**

net/sunrpc/xprtsock.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1739,7 +1739,9 @@ static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t
		*/
		static void xs_udp_timer(struct rpc_xprt xprt, struct rpc_task task)
		{
		spin_lock_bh(&xprt->transport_lock);
		xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
		spin_unlock_bh(&xprt->transport_lock);
		}

		static unsigned short xs_get_random_port(void)

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