Thread (4 messages) flat view 4 messages, 2 authors, 2012-03-22

Re: [PATCH net] tg3: Fix RSS ring refill race condition

From: David Miller <davem@davemloft.net>
Date: 2012-03-22 01:58:32

From: "Michael Chan" <mchan@broadcom.com>
Date: Wed, 21 Mar 2012 17:38:33 -0800
The RSS feature in tg3 hardware has only one rx producer ring for all
RSS rings.  NAPI vector 1 is special and handles the refilling of the
rx producer ring on behalf of all RSS rings.  There is a race condition
between these RSS NAPIs and the NAPI[1].  If NAPI[1] finishes checking
for refill and then another RSS ring empties the rx producer ring
before NAPI[1] exits NAPI, the chip will be completely out of SKBs in
the rx producer ring.

We fix this by adding a flag tp->rx_refill and rely on napi_schedule()/
napi_complete() to help synchronize it to close the race condition.

Update driver version to 3.123.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Applied.
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