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Commit 2bbd6910 authored by Tuomas Tynkkynen's avatar Tuomas Tynkkynen Committed by Greg Kroah-Hartman
Browse files

net/9p: Switch to wait_event_killable() 



commit 9523feac272ccad2ad8186ba4fcc89103754de52 upstream.

Because userspace gets Very Unhappy when calls like stat() and execve()
return -EINTR on 9p filesystem mounts. For instance, when bash is
looking in PATH for things to execute and some SIGCHLD interrupts
stat(), bash can throw a spurious 'command not found' since it doesn't
retry the stat().

In practice, hitting the problem is rare and needs a really
slow/bogged down 9p server.

Signed-off-by: default avatarTuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 49fd514f

net/9p/client.c

+1 −2
Original line number Diff line number Diff line
@@ -753,8 +753,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) 
	}

again:

	/* Wait for the response */

	err = wait_event_interruptible(*req->wq,

				       req->status >= REQ_STATUS_RCVD);

	err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);



	/*

	 * Make sure our req is coherent with regard to updates in other

net/9p/trans_virtio.c

+6 −7
Original line number Diff line number Diff line
@@ -292,7 +292,7 @@ req_retry: 
		if (err == -ENOSPC) {

			chan->ring_bufs_avail = 0;

			spin_unlock_irqrestore(&chan->lock, flags);

			err = wait_event_interruptible(*chan->vc_wq,

			err = wait_event_killable(*chan->vc_wq,

						  chan->ring_bufs_avail);

			if (err  == -ERESTARTSYS)

				return err;
@@ -324,7 +324,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, 
		 * Other zc request to finish here

		 */

		if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {

			err = wait_event_interruptible(vp_wq,

			err = wait_event_killable(vp_wq,

			      (atomic_read(&vp_pinned) < chan->p9_max_pages));

			if (err == -ERESTARTSYS)

				return err;
@@ -454,7 +454,7 @@ req_retry_pinned: 
		if (err == -ENOSPC) {

			chan->ring_bufs_avail = 0;

			spin_unlock_irqrestore(&chan->lock, flags);

			err = wait_event_interruptible(*chan->vc_wq,

			err = wait_event_killable(*chan->vc_wq,

						  chan->ring_bufs_avail);

			if (err  == -ERESTARTSYS)

				goto err_out;
@@ -472,8 +472,7 @@ req_retry_pinned: 
	virtqueue_kick(chan->vq);

	spin_unlock_irqrestore(&chan->lock, flags);

	p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");

	err = wait_event_interruptible(*req->wq,

				       req->status >= REQ_STATUS_RCVD);

	err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);

	/*

	 * Non kernel buffers are pinned, unpin them

	 */