* [PATCH] ibm emac: Don't call napi_complete if napi_reschedule failed
@ 2013-10-24 3:36 Alistair Popple
2013-10-25 23:13 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Alistair Popple @ 2013-10-24 3:36 UTC (permalink / raw)
To: netdev, davem; +Cc: benh, Alistair Popple
This patch fixes a bug which would trigger the BUG_ON() at
net/core/dev.c:4156. It was found that this was due to napi_complete
being called even when the corresponding call to napi_reschedule had
failed.
This patch ensures that we only contine processing rotting packets in
the current mal_poll call if we are not already on the polling list.
It also adds locking calls to protect the read-write-modify of the
MAL_CFG DCR.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
---
drivers/net/ethernet/ibm/emac/mal.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/ibm/emac/mal.c b/drivers/net/ethernet/ibm/emac/mal.c
index 856ea66..b10ad5d 100644
--- a/drivers/net/ethernet/ibm/emac/mal.c
+++ b/drivers/net/ethernet/ibm/emac/mal.c
@@ -263,7 +263,9 @@ static inline void mal_schedule_poll(struct mal_instance *mal)
{
if (likely(napi_schedule_prep(&mal->napi))) {
MAL_DBG2(mal, "schedule_poll" NL);
+ spin_lock(&mal->lock);
mal_disable_eob_irq(mal);
+ spin_unlock(&mal->lock);
__napi_schedule(&mal->napi);
} else
MAL_DBG2(mal, "already in poll" NL);
@@ -442,17 +444,14 @@ static int mal_poll(struct napi_struct *napi, int budget)
if (unlikely(mc->ops->peek_rx(mc->dev) ||
test_bit(MAL_COMMAC_RX_STOPPED, &mc->flags))) {
MAL_DBG2(mal, "rotting packet" NL);
- if (napi_reschedule(napi))
- mal_disable_eob_irq(mal);
- else
- MAL_DBG2(mal, "already in poll list" NL);
-
- if (budget > 0)
- goto again;
- else
+ if (!napi_reschedule(napi))
goto more_work;
+
+ spin_lock_irqsave(&mal->lock, flags);
+ mal_disable_eob_irq(mal);
+ spin_unlock_irqrestore(&mal->lock, flags);
+ goto again;
}
- mc->ops->poll_tx(mc->dev);
}
more_work:
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] ibm emac: Don't call napi_complete if napi_reschedule failed
2013-10-24 3:36 [PATCH] ibm emac: Don't call napi_complete if napi_reschedule failed Alistair Popple
@ 2013-10-25 23:13 ` David Miller
2013-10-29 23:53 ` Alistair Popple
0 siblings, 1 reply; 3+ messages in thread
From: David Miller @ 2013-10-25 23:13 UTC (permalink / raw)
To: alistair; +Cc: netdev, benh
From: Alistair Popple <alistair@popple.id.au>
Date: Thu, 24 Oct 2013 14:36:20 +1100
> This patch fixes a bug which would trigger the BUG_ON() at
> net/core/dev.c:4156. It was found that this was due to napi_complete
> being called even when the corresponding call to napi_reschedule had
> failed.
>
> This patch ensures that we only contine processing rotting packets in
> the current mal_poll call if we are not already on the polling list.
> It also adds locking calls to protect the read-write-modify of the
> MAL_CFG DCR.
>
> Signed-off-by: Alistair Popple <alistair@popple.id.au>
The mistaken napi_complete() call and the locking change are two different
bugs, fix them in two different patches.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-10-24 3:36 [PATCH] ibm emac: Don't call napi_complete if napi_reschedule failed Alistair Popple
2013-10-25 23:13 ` David Miller
2013-10-29 23:53 ` Alistair Popple
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