From: Gerd Hoffmann <kraxel@redhat.com>
Subject: [RHEL-5.1 PATCH 8/10] xen: blktap race #2
Date: Fri, 15 Jun 2007 10:49:20 +0200
Bugzilla: 222128
Message-Id: <46725290.503@redhat.com>
Changelog: [xen] xen: blktap race #2


  Hi,

This patch fixes yet another race in the blktap driver.

cheers,
  Gerd



# HG changeset patch
# User Jake Wires <jwires@xensource.com>
# Date 1163731648 28800
# Node ID f0ba459065d32b61c9d04ccde5787e48e23be782
# Parent  f1d2860c51370f7a89c5b8b6b7941b8975928349
[BLKTAP] fix race between ufe_ring and blk_ring in blktap.c

Signed-off-by: Jake Wires <jwires@xensource.com>

---
 drivers/xen/blktap/blktapmain.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.18.noarch/drivers/xen/blktap/blktapmain.c
===================================================================
--- linux-2.6.18.noarch.orig/drivers/xen/blktap/blktapmain.c
+++ linux-2.6.18.noarch/drivers/xen/blktap/blktapmain.c
@@ -1002,9 +1002,9 @@ static int blktap_read_ufe_ring(tap_blki
 			map[offset] = NULL;
 		}
 		fast_flush_area(pending_req, pending_idx, usr_idx, info->minor);
+		info->idx_map[usr_idx] = INVALID_REQ;
 		make_response(blkif, pending_req->id, res.operation,
 			      res.status);
-		info->idx_map[usr_idx] = INVALID_REQ;
 		blkif_put(pending_req->blkif);
 		free_req(pending_req);
 	}