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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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3
net/9p/client.c
View File

@ -773,8 +773,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
} }
again: again:
/* Wait for the response */ /* Wait for the response */
err = wait_event_interruptible(*req->wq, err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
req->status >= REQ_STATUS_RCVD);
/* /*
* Make sure our req is coherent with regard to updates in other * Make sure our req is coherent with regard to updates in other

13
net/9p/trans_virtio.c
View File

@ -286,8 +286,8 @@ req_retry:
if (err == -ENOSPC) { if (err == -ENOSPC) {
chan->ring_bufs_avail = 0; chan->ring_bufs_avail = 0;
spin_unlock_irqrestore(&chan->lock, flags); spin_unlock_irqrestore(&chan->lock, flags);
err = wait_event_interruptible(*chan->vc_wq, err = wait_event_killable(*chan->vc_wq,
chan->ring_bufs_avail); chan->ring_bufs_avail);
if (err == -ERESTARTSYS) if (err == -ERESTARTSYS)
return err; return err;
@ -327,7 +327,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
* Other zc request to finish here * Other zc request to finish here
*/ */
if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { 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)); (atomic_read(&vp_pinned) < chan->p9_max_pages));
if (err == -ERESTARTSYS) if (err == -ERESTARTSYS)
return err; return err;
@ -471,8 +471,8 @@ req_retry_pinned:
if (err == -ENOSPC) { if (err == -ENOSPC) {
chan->ring_bufs_avail = 0; chan->ring_bufs_avail = 0;
spin_unlock_irqrestore(&chan->lock, flags); spin_unlock_irqrestore(&chan->lock, flags);
err = wait_event_interruptible(*chan->vc_wq, err = wait_event_killable(*chan->vc_wq,
chan->ring_bufs_avail); chan->ring_bufs_avail);
if (err == -ERESTARTSYS) if (err == -ERESTARTSYS)
goto err_out; goto err_out;
@ -489,8 +489,7 @@ req_retry_pinned:
virtqueue_kick(chan->vq); virtqueue_kick(chan->vq);
spin_unlock_irqrestore(&chan->lock, flags); spin_unlock_irqrestore(&chan->lock, flags);
p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
err = wait_event_interruptible(*req->wq, err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
req->status >= REQ_STATUS_RCVD);
/* /*
* Non kernel buffers are pinned, unpin them * Non kernel buffers are pinned, unpin them
*/ */

4
net/9p/trans_xen.c
View File

@ -156,8 +156,8 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
ring = &priv->rings[num]; ring = &priv->rings[num];
again: again:
while (wait_event_interruptible(ring->wq, while (wait_event_killable(ring->wq,
p9_xen_write_todo(ring, size)) != 0) p9_xen_write_todo(ring, size)) != 0)
; ;
spin_lock_irqsave(&ring->lock, flags); spin_lock_irqsave(&ring->lock, flags);