forcedeth: xmit lock fix
Subsystems (2)
PATCH 2/4 forcedeth: xmit lock fix
This patch fixes a potential race condition between xmit thread and xmit completion thread. The calculation of empty tx descriptors is not performed under the lock. This could cause it to set the stop flag while the completion thread finishes all tx's. This will result in the tx queue in stopped state and no one to wake it up.
drivers/net/forcedeth.c +4 -2
@@ -2096,14 +2096,15 @@ ((skb_shinfo (skb)->frags[i].size & (NV_TX2_TSO_MAX_SIZE -1 )) ?1 :0 ); } +spin_lock_irqsave (&np->lock, flags); empty_slots =nv_get_empty_tx_slots (np);if (unlikely (empty_slots <= entries)) { -spin_lock_irqsave (&np->lock, flags);netif_stop_queue (dev); np->tx_stop =1 ;spin_unlock_irqrestore (&np->lock, flags);return NETDEV_TX_BUSY ; } +spin_unlock_irqrestore (&np->lock, flags); start_tx = put_tx = np->put_tx.orig;
@@ -2214,14 +2215,15 @@ ((skb_shinfo (skb)->frags[i].size & (NV_TX2_TSO_MAX_SIZE -1 )) ?1 :0 ); } +spin_lock_irqsave (&np->lock, flags); empty_slots =nv_get_empty_tx_slots (np);if (unlikely (empty_slots <= entries)) { -spin_lock_irqsave (&np->lock, flags);netif_stop_queue (dev); np->tx_stop =1 ;spin_unlock_irqrestore (&np->lock, flags);return NETDEV_TX_BUSY ; } +spin_unlock_irqrestore (&np->lock, flags); start_tx = put_tx = np->put_tx.ex; start_tx_ctx = np->put_tx_ctx;
From: Ayaz Abdulla <[email protected]>
Date: Fri, 09 Jan 2009 16:03:44 -0500
Quoted 3 lines
This patch fixes a potential race condition between xmit thread and xmit completion thread. The calculation of empty tx descriptors is not performed under the lock. This could cause it to set the stop flag while the completion thread finishes all tx's. This will result in the tx queue in stopped state and no one to wake it up.
Signed-off-by Ayaz Abdulla <[email protected]>
Applied.