[git patch] net driver fix

[Jeff Garzik <jeff@garzik.org>]

As the patch indicates, the Al Viro patch had already been merged into
my history (and another branch depending on it, making rebasing
difficult if not impossible), but since it was merged by Linus, the
actual patch isn't shown here by 'git diff'.

Please pull from 'upstream-linus' branch of
master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6.git upstream-linus

to receive the following updates:

 drivers/net/mv643xx_eth.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

Al Viro (1):
      s2io bogus memset

Dale Farnsworth (1):
      mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs

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
@@ -314,6 +314,13 @@ int mv643xx_eth_free_tx_descs(struct net_device *dev, int force)
 
 	while (mp->tx_desc_count > 0) {
 		spin_lock_irqsave(&mp->lock, flags);
+
+		/* tx_desc_count might have changed before acquiring the lock */
+		if (mp->tx_desc_count <= 0) {
+			spin_unlock_irqrestore(&mp->lock, flags);
+			return released;
+		}
+
 		tx_index = mp->tx_used_desc_q;
 		desc = &mp->p_tx_desc_area[tx_index];
 		cmd_sts = desc->cmd_sts;
@@ -332,13 +339,13 @@ int mv643xx_eth_free_tx_descs(struct net_device *dev, int force)
 		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++;
 		}
 
+		spin_unlock_irqrestore(&mp->lock, flags);
+
 		if (cmd_sts & ETH_TX_FIRST_DESC)
 			dma_unmap_single(NULL, addr, count, DMA_TO_DEVICE);
 		else