diff mbox series

[v4] net/virtio: fix wrong variable assignment in helper macro

Message ID 20200916055725.1473-1-vipul.ashri@oracle.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series [v4] net/virtio: fix wrong variable assignment in helper macro |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Performance-Testing fail build patch failure
ci/Intel-compilation fail Compilation issues
ci/travis-robot warning Travis build: failed

Commit Message

Vipul Ashri Sept. 16, 2020, 5:57 a.m. UTC 
  Inside Macro ASSIGN_UNLESS_EQUAL(var, val), assignment to var is always
failing as assignment done using var_ having local scope only.
This leads to TX packets not going out and found broken due to cleanup
malfunctioning. This patch fixes the wrong variable assignment.

Fixes: 57f90f894588 ("net/virtio: reuse packed ring functions")
Cc: stable@dpdk.org

Signed-off-by: Vipul Ashri <vipul.ashri@oracle.com>
---
 drivers/net/virtio/virtqueue.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Andrew Rybchenko Sept. 17, 2020, 3:54 p.m. UTC | #1 
On 9/16/20 8:57 AM, Vipul Ashri wrote:
> Inside Macro ASSIGN_UNLESS_EQUAL(var, val), assignment to var is always
> failing as assignment done using var_ having local scope only.
> This leads to TX packets not going out and found broken due to cleanup
> malfunctioning. This patch fixes the wrong variable assignment.
> 
> Fixes: 57f90f894588 ("net/virtio: reuse packed ring functions")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Vipul Ashri <vipul.ashri@oracle.com>

Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
diff mbox series

Patch

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 105a9c00c..7f8a3976f 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -607,10 +607,11 @@  virtqueue_notify(struct virtqueue *vq)
 
 /* avoid write operation when necessary, to lessen cache issues */
 #define ASSIGN_UNLESS_EQUAL(var, val) do {	\
-	typeof(var) var_ = (var);		\
-	typeof(val) val_ = (val);		\
-	if ((var_) != (val_))			\
-		(var_) = (val_);		\
+	typeof(var) *const var_ = &(var);	\
+	typeof(val)  const val_ = (val);	\
+	if (*var_ != val_)			\
+		*var_ = val_;			\
+
 } while (0)
 
 #define virtqueue_clear_net_hdr(hdr) do {		\