[PATCH net-next v5 2/2] net: mana: Use the correct WQE count for ringing RQ doorbell

[longli@linuxonhyperv.com]

From: Long Li <longli@microsoft.com>

The hardware specification specifies that WQE_COUNT should set to 0 for
the Receive Queue. Although currently the hardware doesn't enforce the
check, in the future releases it may check on this value.

Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Long Li <longli@microsoft.com>
---
Change log:
v4:
Split the original patch into two: one for batching doorbell, one for setting the correct wqe count

v5:
Drop Cc: stable and use net-next

 drivers/net/ethernet/microsoft/mana/gdma_main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 8f3f78b68592..3765d3389a9a 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -300,8 +300,11 @@ static void mana_gd_ring_doorbell(struct gdma_context *gc, u32 db_index,
 
 void mana_gd_wq_ring_doorbell(struct gdma_context *gc, struct gdma_queue *queue)
 {
+	/* Hardware Spec specifies that software client should set 0 for
+	 * wqe_cnt for Receive Queues. This value is not used in Send Queues.
+	 */
 	mana_gd_ring_doorbell(gc, queue->gdma_dev->doorbell, queue->type,
-			      queue->id, queue->head * GDMA_WQE_BU_SIZE, 1);
+			      queue->id, queue->head * GDMA_WQE_BU_SIZE, 0);
 }
 
 void mana_gd_ring_cq(struct gdma_queue *cq, u8 arm_bit)
-- 
2.34.1