From: Lennert Buytenhek Date: Sat, 23 Aug 2008 23:59:05 +0000 (+0200) Subject: mv643xx_eth: fix double add_timer() on the receive oom timer X-Git-Tag: v2.6.27-rc5~8^2~4^2~30^2~4 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=92c70f27d2a78873c940e77c7f075cd8e2e60a2d;p=linux-2.6 mv643xx_eth: fix double add_timer() on the receive oom timer Commit 12e4ab79cd828563dc090d2117dc8626b344bc8f ("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 --- diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c index af279f26c4..8a91d79383 100644 --- a/drivers/net/mv643xx_eth.c +++ b/drivers/net/mv643xx_eth.c @@ -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); }