[PATCH 3.15 12/26] bna: fix performance regression

From: Greg Kroah-Hartman
Date: Fri Aug 08 2014 - 17:52:08 EST

3.15-stable review patch. If anyone has any objections, please let me know.


From: Ivan Vecera <ivecera@xxxxxxxxxx>

[ Upstream commit c36c9d50cc6af5c5bfcc195f21b73f55520c15f9 ]

The recent commit "e29aa33 bna: Enable Multi Buffer RX" is causing
a performance regression. It does not properly update 'cmpl' pointer
at the end of the loop in NAPI handler bnad_cq_process(). The result is
only one packet / per NAPI-schedule is processed.

Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/ethernet/brocade/bna/bnad.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -600,9 +600,9 @@ bnad_cq_process(struct bnad *bnad, struc

cq = ccb->sw_q;
- cmpl = &cq[ccb->producer_index];

while (packets < budget) {
+ cmpl = &cq[ccb->producer_index];
if (!cmpl->valid)
/* The 'valid' field is set by the adapter, only after writing

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