From: kfraser@dhcp93.uk.xensource.com <kfraser@dhcp93.uk.xensource.com>
Date: Tue, 13 Jun 2006 14:13:29 +0000 (+0100)
Subject: [LINUX] Fix blkfront driver to check connection status to backend in
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15955^2~20^2
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=ade82aac45e5636d9408016ee0316d9a26c5ddef;p=xen.git

[LINUX] Fix blkfront driver to check connection status to backend in
all critical circumstances.
Signed-off-by: Keir Fraser <keir@xensource.com>
---

diff --git a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
index 433d7389fe..bb71828909 100644
--- a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
+++ b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
@@ -407,7 +407,8 @@ static void blkif_restart_queue(void *arg)
 {
 	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 *rq)
 			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 blkfront_info *info)
 
 	(void)xenbus_switch_state(info->xbdev, XenbusStateConnected);
 
-	/* Now safe for us to use the shared ring */
 	spin_lock_irq(&blkif_io_lock);
+
+	/* Now safe for us to use the shared ring */
 	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);
 }