bna: fix interrupts storm caused by erroneous packets

This change “bna: fix interrupts storm caused by erroneous packets” in Linux kernel is authored by Ivan Vecera <ivecera [at] redhat.com> on Thu Aug 6 22:48:23 2015 +0200.

bna: fix interrupts storm caused by erroneous packets

The commit "e29aa33 bna: Enable Multi Buffer RX" moved packets counter
increment from the beginning of the NAPI processing loop after the check
for erroneous packets so they are never accounted. This counter is used
to inform firmware about number of processed completions (packets).
As these packets are never acked the firmware fires IRQs for them again
and again.

Fixes: e29aa33 ("bna: Enable Multi Buffer RX")
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit ade4dc3.

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/net/ethernet/brocade/bna/bnad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
index 0612b19..506047c 100644
--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -676,6 +676,7 @@
 			if (!next_cmpl->valid)
 				break;
 		}
+		packets++;
 
 		/* TODO: BNA_CQ_EF_LOCAL ? */
 		if (unlikely(flags & (BNA_CQ_EF_MAC_ERROR |
@@ -692,7 +693,6 @@
 		else
 			bnad_cq_setup_skb_frags(rcb, skb, sop_ci, nvecs, len);
 
-		packets++;
 		rcb->rxq->rx_packets++;
 		rcb->rxq->rx_bytes += totlen;
 		ccb->bytes_per_intr += totlen;

The commit for this change in Linux stable tree is ade4dc3 (patch).

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