drivers/net: fixed drivers that support netpoll use ndo_start_xmit()
The NETPOLL API requires that interrupts remain disabled in
netpoll_send_skb(). The use of "A functions set" in the NETPOLL API
callbacks causes the interrupts to get enabled and can lead to kernel
instability.
The solution is to use "B functions set" to prevent the irqs from
getting enabled while in netpoll_send_skb().
A functions set:
local_irq_disable()/local_irq_enable()
spin_lock_irq()/spin_unlock_irq()
spin_trylock_irq()/spin_unlock_irq()
B functions set:
local_irq_save()/local_irq_restore()
spin_lock_irqsave()/spin_unlock_irqrestore()
spin_trylock_irqsave()/spin_unlock_irqrestore()
Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 5b5c253..e3601cf3 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -620,6 +620,7 @@
dma_addr_t mapping;
unsigned int len, entry;
u32 ctrl;
+ unsigned long flags;
#ifdef DEBUG
int i;
@@ -635,12 +636,12 @@
#endif
len = skb->len;
- spin_lock_irq(&bp->lock);
+ spin_lock_irqsave(&bp->lock, flags);
/* This is a hard error, log it. */
if (TX_BUFFS_AVAIL(bp) < 1) {
netif_stop_queue(dev);
- spin_unlock_irq(&bp->lock);
+ spin_unlock_irqrestore(&bp->lock, flags);
dev_err(&bp->pdev->dev,
"BUG! Tx Ring full when queue awake!\n");
dev_dbg(&bp->pdev->dev, "tx_head = %u, tx_tail = %u\n",
@@ -674,7 +675,7 @@
if (TX_BUFFS_AVAIL(bp) < 1)
netif_stop_queue(dev);
- spin_unlock_irq(&bp->lock);
+ spin_unlock_irqrestore(&bp->lock, flags);
dev->trans_start = jiffies;