Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d344bff9c36db17dc4765215495aaa7212c1eb6c
Commit:     d344bff9c36db17dc4765215495aaa7212c1eb6c
Parent:     3196265e97c661d9e9be04d5d64ca8ff3186536d
Author:     Dale Farnsworth <[EMAIL PROTECTED]>
AuthorDate: Tue Jan 23 09:52:25 2007 -0700
Committer:  Jeff Garzik <[EMAIL PROTECTED]>
CommitDate: Tue Jan 23 16:28:53 2007 -0500

    mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs
    
    mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs
    
    This bug was found and isolated by Thibaut VARENE <[EMAIL PROTECTED]>
    and Jarek Poplawski <[EMAIL PROTECTED]>.  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.
    
    Signed-off-by: Jeff Garzik <[EMAIL PROTECTED]>
---
 drivers/net/mv643xx_eth.c |   11 +++++++++--
 1 files 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
@@ -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
-
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