[PATCH 4.4 12/17] xen/blkfront: fix bug in backported patch

Greg Kroah-Hartman
2021-12-27T15:27:36Z

From: Juergen Gross <jgross@suse.com>

The backport of commit 8f5a695d99000fc ("xen/blkfront: don't take local
copy of a request from the ring page") to stable 4.4 kernel introduced
a bug when adding the needed blkif_ring_get_request() function, as
info->ring.req_prod_pvt was incremented twice now.

Fix that be deleting the now superfluous increments after calling that
function.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/xen-blkfront.c | 4 ----
1 file changed, 4 deletions(-)

--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -493,8 +493,6 @@ static int blkif_queue_discard_req(struc
else
ring_req->u.discard.flag = 0;

- info->ring.req_prod_pvt++;
-
/* Copy the request to the ring page. */
*final_ring_req = *ring_req;
info->shadow[id].inflight = true;
@@ -711,8 +709,6 @@ static int blkif_queue_rw_req(struct req
if (setup.segments)
kunmap_atomic(setup.segments);

- info->ring.req_prod_pvt++;
-
/* Copy request(s) to the ring page. */
*final_ring_req = *ring_req;
info->shadow[id].inflight = true;