[Xen-changelog] [xen-unstable] [LINUX] Fix blkfront driver to check connection status to backend in

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxxxx
# Node ID 91d2f2258c563100d5294fe12fd9fbe56870b213
# Parent  1650e07c9e5261dc823e156dc0a9350e98f870bc
[LINUX] Fix blkfront driver to check connection status to backend in
all critical circumstances.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff -r 1650e07c9e52 -r 91d2f2258c56 
linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c      Tue Jun 13 
14:36:04 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c      Tue Jun 13 
15:13:29 2006 +0100
@@ -407,7 +407,8 @@ static void blkif_restart_queue(void *ar
 {
        struct blkfront_info *info = (struct blkfront_info *)arg;
        spin_lock_irq(&blkif_io_lock);
-       kick_pending_request_queues(info);
+       if (info->connected == BLKIF_STATE_CONNECTED)
+               kick_pending_request_queues(info);
        spin_unlock_irq(&blkif_io_lock);
 }
 
@@ -595,7 +596,8 @@ void do_blkif_request(request_queue_t *r
                        continue;
                }
 
-               if (RING_FULL(&info->ring))
+               if (unlikely(info->connected != BLKIF_STATE_CONNECTED) ||
+                   RING_FULL(&info->ring))
                        goto wait;
 
                DPRINTK("do_blk_req %p: cmd %p, sec %lx, "
@@ -768,17 +770,17 @@ static void blkif_recover(struct blkfron
 
        (void)xenbus_switch_state(info->xbdev, XenbusStateConnected);
 
+       spin_lock_irq(&blkif_io_lock);
+
        /* Now safe for us to use the shared ring */
-       spin_lock_irq(&blkif_io_lock);
        info->connected = BLKIF_STATE_CONNECTED;
-       spin_unlock_irq(&blkif_io_lock);
 
        /* Send off requeued requests */
        flush_requests(info);
 
        /* Kick any other new requests queued since we resumed */
-       spin_lock_irq(&blkif_io_lock);
        kick_pending_request_queues(info);
+
        spin_unlock_irq(&blkif_io_lock);
 }
 

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