[PATCH net] gve: Remove the code of clearing PBA bit

[PATCH net] gve: Remove the code of clearing PBA bit

[Ziwei Xiao]

Clearing the PBA bit from the driver is race prone and it may lead to
dropped interrupt events. This could potentially lead to the traffic
being completely halted.

Fixes: 5e8c5adf95f8 ("gve: DQO: Add core netdev features")
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Bailey Forrest <bcf@google.com>
---
 drivers/net/ethernet/google/gve/gve_main.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 57ce74315eba..caa00c72aeeb 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -294,19 +294,6 @@ static int gve_napi_poll_dqo(struct napi_struct *napi, int budget)
 	bool reschedule = false;
 	int work_done = 0;
 
-	/* Clear PCI MSI-X Pending Bit Array (PBA)
-	 *
-	 * This bit is set if an interrupt event occurs while the vector is
-	 * masked. If this bit is set and we reenable the interrupt, it will
-	 * fire again. Since we're just about to poll the queue state, we don't
-	 * need it to fire again.
-	 *
-	 * Under high softirq load, it's possible that the interrupt condition
-	 * is triggered twice before we got the chance to process it.
-	 */
-	gve_write_irq_doorbell_dqo(priv, block,
-				   GVE_ITR_NO_UPDATE_DQO | GVE_ITR_CLEAR_PBA_BIT_DQO);
-
 	if (block->tx)
 		reschedule |= gve_tx_poll_dqo(block, /*do_clean=*/true);
 
-- 
2.40.1.521.gf1e218fcd8-goog

Re: [PATCH net] gve: Remove the code of clearing PBA bit

[Simon Horman]

On Tue, May 09, 2023 at 03:51:23PM -0700, Ziwei Xiao wrote:
> Clearing the PBA bit from the driver is race prone and it may lead to
> dropped interrupt events. This could potentially lead to the traffic
> being completely halted.
> 
> Fixes: 5e8c5adf95f8 ("gve: DQO: Add core netdev features")
> Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
> Signed-off-by: Bailey Forrest <bcf@google.com>

Reviewed-by: Simon Horman <simon.horman@corigine.com>

Re: [PATCH net] gve: Remove the code of clearing PBA bit

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Tue,  9 May 2023 15:51:23 -0700 you wrote:
> Clearing the PBA bit from the driver is race prone and it may lead to
> dropped interrupt events. This could potentially lead to the traffic
> being completely halted.
> 
> Fixes: 5e8c5adf95f8 ("gve: DQO: Add core netdev features")
> Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
> Signed-off-by: Bailey Forrest <bcf@google.com>
> 
> [...]

Here is the summary with links:
  - [net] gve: Remove the code of clearing PBA bit
    https://git.kernel.org/netdev/net/c/f4c2e67c1773

You are awesome, thank you!
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