Re: [PATCH] mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs

["Thibaut VARENE" <T-Bone@parisc-linux.org>]

On 1/23/07, Dale Farnsworth <dale@farnsworth.org> wrote:
> From Dale Farnsworth <dale@farnsworth.org>
>
> mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs
>
> This bug was found and isolated by Thibaut VARENE <T-Bone@parisc-linux.org>
> and Jarek Poplawski <jarkao2@o2.pl>.  This patch is a modification of their
> fixes.  We acquire and release the lock for each descriptor that is freed
> to minimize the time the lock is held.
>
> ---
>
>  drivers/net/mv643xx_eth.c |   11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
> index c41ae42..b3bf864 100644
> --- a/drivers/net/mv643xx_eth.c
> +++ b/drivers/net/mv643xx_eth.c
> @@ -332,13 +339,13 @@ int mv643xx_eth_free_tx_descs(struct net
>                 if (skb)
>                         mp->tx_skb[tx_index] = NULL;
>
> -               spin_unlock_irqrestore(&mp->lock, flags);
> -
>                 if (cmd_sts & ETH_ERROR_SUMMARY) {
>                         printk("%s: Error in TX\n", dev->name);
>                         mp->stats.tx_errors++;
>                 }

Note that this printk probably won't show immediately because IRQs are
disabled. But that's maybe not a big deal.

HTH

-- 
Thibaut VARENE
http://www.parisc-linux.org/~varenet/