diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-10-17 20:27:48 +0200 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-10-17 20:28:57 +0200 |
| commit | 6927d92091df2848fc0e6a693a017d4b2df549c2 (patch) | |
| tree | 31fc8055bad35f8daf4325a252018dd5ff0a9150 /drivers/block | |
| parent | xen/blkback: Check for proper operation. (diff) | |
| download | linux-6927d92091df2848fc0e6a693a017d4b2df549c2.tar.xz linux-6927d92091df2848fc0e6a693a017d4b2df549c2.zip | |
xen/blkback: Fix two races in the handling of barrier requests.
There are two windows of opportunity to cause a race when
processing a barrier request. This patch fixes this.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index a1ee2659d2bc..79efec24569b 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -456,15 +456,15 @@ static void xen_blk_drain_io(struct xen_blkif *blkif) { atomic_set(&blkif->drain, 1); do { + /* The initial value is one, and one refcnt taken at the + * start of the xen_blkif_schedule thread. */ + if (atomic_read(&blkif->refcnt) <= 2) + break; wait_for_completion_interruptible_timeout( &blkif->drain_complete, HZ); if (!atomic_read(&blkif->drain)) break; - /* The initial value is one, and one refcnt taken at the - * start of the xen_blkif_schedule thread. */ - if (atomic_read(&blkif->refcnt) <= 2) - break; } while (!kthread_should_stop()); atomic_set(&blkif->drain, 0); } @@ -502,11 +502,11 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) make_response(pending_req->blkif, pending_req->id, pending_req->operation, pending_req->status); xen_blkif_put(pending_req->blkif); - free_req(pending_req); if (atomic_read(&pending_req->blkif->refcnt) <= 2) { if (atomic_read(&pending_req->blkif->drain)) complete(&pending_req->blkif->drain_complete); } + free_req(pending_req); } } |