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net/9p: Switch to wait_event_killable()

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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.

Cc: stable@vger.kernel.org
Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Tuomas Tynkkynen
2017-09-06 17:59:08 +03:00
committed by Al Viro
parent 8ee0316315
commit 9523feac27
3 changed files with 9 additions and 11 deletions
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13
net/9p/trans_virtio.c
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@@ -286,8 +286,8 @@ req_retry:
if (err == -ENOSPC) {
chan->ring_bufs_avail = 0;
spin_unlock_irqrestore(&chan->lock, flags);
err = wait_event_interruptible(*chan->vc_wq,
chan->ring_bufs_avail);
err = wait_event_killable(*chan->vc_wq,
chan->ring_bufs_avail);
if (err == -ERESTARTSYS)
return err;
@@ -327,7 +327,7 @@ 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;
@@ -471,8 +471,8 @@ req_retry_pinned:
if (err == -ENOSPC) {
chan->ring_bufs_avail = 0;
spin_unlock_irqrestore(&chan->lock, flags);
err = wait_event_interruptible(*chan->vc_wq,
chan->ring_bufs_avail);
err = wait_event_killable(*chan->vc_wq,
chan->ring_bufs_avail);
if (err == -ERESTARTSYS)
goto err_out;
@@ -489,8 +489,7 @@ 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
*/