net/9p: Switch to wait_event_killable()

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>

3 files changed, 9 insertions, 11 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 4674235b0d9b..1beb131dd3e1 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -773,8 +773,7 @@ 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
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index f24b25c25106..f3a4efcf1456 100644
--- 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 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
          */
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 6ad3e043c617..325c56043007 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -156,8 +156,8 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
         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);