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

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Date: Tue,  9 May 2023 15:51:23 -0700
From: Ziwei Xiao <ziweixiao@...gle.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, Ziwei Xiao <ziweixiao@...gle.com>, 
	Bailey Forrest <bcf@...gle.com>
Subject: [PATCH net] gve: Remove the code of clearing PBA bit

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@...gle.com>
Signed-off-by: Bailey Forrest <bcf@...gle.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