From: Michael Chan <michael.chan@broadcom.com>
Date: Mon, 28 Aug 2017 13:40:30 -0400
Subject: bnxt_en: Improve -ENOMEM logic in NAPI poll loop.
Patch-mainline: v4.14-rc1
Git-commit: 903649e718f80da2ba4b65a0adf6930219b4b2e5
References: bsc#1050242 FATE#32291

If we cannot allocate RX buffers in the NAPI poll loop when processing
an RX event, the current code does not count that event towards the NAPI
budget.  This can cause us to potentially loop forever in NAPI if we
consistently cannot allocate new buffers.  Improve it by counting
-ENOMEM event as 1 towards the NAPI budget.

Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reported-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -1850,6 +1850,13 @@ static int bnxt_poll_work(struct bnxt *b
 							   &event);
 			if (likely(rc >= 0))
 				rx_pkts += rc;
+			/* Increment rx_pkts when rc is -ENOMEM to count towards
+			 * the NAPI budget.  Otherwise, we may potentially loop
+			 * here forever if we consistently cannot allocate
+			 * buffers.
+			 */
+			else if (rc == -ENOMEM)
+				rx_pkts++;
 			else if (rc == -EBUSY)	/* partial completion */
 				break;
 		} else if (unlikely((TX_CMP_TYPE(txcmp) ==