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Subject[PATCH 4.14 103/193] net/9p: Switch to wait_event_killable()
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tuomas Tynkkynen <tuomas@tuxera.com>

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: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/9p/client.c | 3 +--
net/9p/trans_virtio.c | 13 ++++++-------
net/9p/trans_xen.c | 4 ++--
3 files changed, 9 insertions(+), 11 deletions(-)

--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -773,8 +773,7 @@ p9_client_rpc(struct p9_client *c, int8_
}
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
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -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 vi
* 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
*/
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -156,8 +156,8 @@ static int p9_xen_request(struct p9_clie
ring = &priv->rings[num];

again:
- while (wait_event_interruptible(ring->wq,
- p9_xen_write_todo(ring, size)) != 0)
+ while (wait_event_killable(ring->wq,
+ p9_xen_write_todo(ring, size)) != 0)
;

spin_lock_irqsave(&ring->lock, flags);

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