[PATCH 4.9 086/138] net/9p: Switch to wait_event_killable()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Tuomas Tynkkynen <tuo...@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 <tuo...@tuxera.com>
Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>


---
 net/9p/client.c       |    3 +--
 net/9p/trans_virtio.c |   13 ++++++-------
 2 files changed, 7 insertions(+), 9 deletions(-)

--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -749,8 +749,7 @@ 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
         */