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mv643xx_eth: fix double add_timer() on the receive oom timer 

Commit 12e4ab79cd ("mv643xx_eth: be
more agressive about RX refill") changed the condition for the receive
out-of-memory timer to be scheduled from "the receive ring is empty"
to "the receive ring is not full".

This can lead to a situation where the receive out-of-memory timer is
pending because a previous rxq_refill() didn't manage to refill the
receive ring entirely as a result of being out of memory, and
rxq_refill() is then called again as a side effect of a packet receive
interrupt, and that rxq_refill() call then again does not succeed to
refill the entire receive ring with fresh empty skbuffs because we are
still out of memory, and then tries to call add_timer() on the already
scheduled out-of-memory timer.

This patch fixes this issue by changing the add_timer() call in
rxq_refill() to a mod_timer() call.  If the OOM timer was not already
scheduled, this will behave as before, whereas if it was already
scheduled, this patch will push back its firing time a bit, which is
safe because we've (unsuccessfully) attempted to refill the receive
ring just before we do this.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
This commit is contained in:
Lennert Buytenhek 2008-08-24 01:59:05 +02:00 committed by Lennert Buytenhek
parent 819ddcafb3
commit 92c70f27d2
1 changed files with 2 additions and 4 deletions
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6
drivers/net/mv643xx_eth.c
View File

@ -509,10 +509,8 @@ static void rxq_refill(struct rx_queue *rxq)
skb_reserve(skb, 2);
}
if (rxq->rx_desc_count != rxq->rx_ring_size) {
rxq->rx_oom.expires = jiffies + (HZ / 10);
add_timer(&rxq->rx_oom);
}
if (rxq->rx_desc_count != rxq->rx_ring_size)
mod_timer(&rxq->rx_oom, jiffies + (HZ / 10));
spin_unlock_irqrestore(&mp->lock, flags);
}