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.
Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 5b68dc2..6905ec9 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -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;