From: Catherine Sullivan <csully@xxxxxxxxxx>
[ Upstream commit f81781835f0adfae8d701545386030d223efcd6f ]
As currently written, if the driver checks for more work (via
gve_tx_poll or gve_rx_poll) before the device posts work and the
irq doorbell is not unmasked
(via iowrite32be(GVE_IRQ_ACK | GVE_IRQ_EVENT, ...)) before the device
attempts to raise an interrupt, an interrupt is lost and this could
potentially lead to the traffic being completely halted. For
example, if a tx queue has already been stopped, the driver won't get
the chance to complete work and egress will be halted.
We need a full memory barrier in the poll
routine to ensure that the irq doorbell is unmasked before the driver
checks for more work.
Fixes: f5cedc84a30d ("gve: Add transmit and receive support")
Signed-off-by: Catherine Sullivan <csully@xxxxxxxxxx>
Signed-off-by: David Awogbemila <awogbemila@xxxxxxxxxx>
Acked-by: Willem de Brujin <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/google/gve/gve_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 839102ea6aa1..d6e35421d8f7 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -180,7 +180,7 @@ static int gve_napi_poll(struct napi_struct *napi, int budget)
/* Double check we have no extra work.
* Ensure unmask synchronizes with checking for work.
*/
- dma_rmb();
+ mb();
if (block->tx)
reschedule |= gve_tx_poll(block, -1);
if (block->rx)
--
2.30.2
