amd-xgbe: Enable IRQs only if napi_complete_done() is true

BugLink: http://bugs.launchpad.net/bugs/1675032
[ Upstream commit d7aba644ffdebf756e51e26a2229055211838e89 ]

Depending on the hardware, the amd-xgbe driver may use disable_irq_nosync()
and enable_irq() when an interrupt is received to process Rx packets. If
the napi_complete_done() return value isn't checked an unbalanced enable
for the IRQ could result, generating a warning stack trace.

Update the driver to only enable interrupts if napi_complete_done() returns
true.

Reported-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 0f4bbe1fd5dc8afb96c61c38cb6b0d90d63611fd..742e5d1b5da45aaaf1073fa1dda9c42b343661ba 100644 (file)
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -2274,10 +2274,7 @@ static int xgbe_one_poll(struct napi_struct *napi, int budget)
        processed = xgbe_rx_poll(channel, budget);
 
        /* If we processed everything, we are done */
-       if (processed < budget) {
-               /* Turn off polling */
-               napi_complete_done(napi, processed);
-
+       if ((processed < budget) && napi_complete_done(napi, processed)) {
                /* Enable Tx and Rx interrupts */
                if (pdata->channel_irq_mode)
                        xgbe_enable_rx_tx_int(pdata, channel);
@@ -2319,10 +2316,7 @@ static int xgbe_all_poll(struct napi_struct *napi, int budget)
        } while ((processed < budget) && (processed != last_processed));
 
        /* If we processed everything, we are done */
-       if (processed < budget) {
-               /* Turn off polling */
-               napi_complete_done(napi, processed);
-
+       if ((processed < budget) && napi_complete_done(napi, processed)) {
                /* Enable Tx and Rx interrupts */
                xgbe_enable_rx_tx_ints(pdata);
        }