[NET]: Add netif_tx_lock
Various drivers use xmit_lock internally to synchronise with their
transmission routines. They do so without setting xmit_lock_owner.
This is fine as long as netpoll is not in use.
With netpoll it is possible for deadlocks to occur if xmit_lock_owner
isn't set. This is because if a printk occurs while xmit_lock is held
and xmit_lock_owner is not set can cause netpoll to attempt to take
xmit_lock recursively.
While it is possible to resolve this by getting netpoll to use
trylock, it is suboptimal because netpoll's sole objective is to
maximise the chance of getting the printk out on the wire. So
delaying or dropping the message is to be avoided as much as possible.
So the only alternative is to always set xmit_lock_owner. The
following patch does this by introducing the netif_tx_lock family of
functions that take care of setting/unsetting xmit_lock_owner.
I renamed xmit_lock to _xmit_lock to indicate that it should not be
used directly. I didn't provide irq versions of the netif_tx_lock
functions since xmit_lock is meant to be a BH-disabling lock.
This is pretty much a straight text substitution except for a small
bug fix in winbond. It currently uses
netif_stop_queue/spin_unlock_wait to stop transmission. This is
unsafe as an IRQ can potentially wake up the queue. So it is safer to
use netif_tx_disable.
The hamradio bits used spin_lock_irq but it is unnecessary as
xmit_lock must never be taken in an IRQ handler.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 1dae4b2..1d917ed 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -821,7 +821,8 @@
ipoib_mcast_stop_thread(dev, 0);
- spin_lock_irqsave(&dev->xmit_lock, flags);
+ local_irq_save(flags);
+ netif_tx_lock(dev);
spin_lock(&priv->lock);
/*
@@ -896,7 +897,8 @@
}
spin_unlock(&priv->lock);
- spin_unlock_irqrestore(&dev->xmit_lock, flags);
+ netif_tx_unlock(dev);
+ local_irq_restore(flags);
/* We have to cancel outside of the spinlock */
list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
diff --git a/drivers/media/dvb/dvb-core/dvb_net.c b/drivers/media/dvb/dvb-core/dvb_net.c
index 2f0f358..9fd8752 100644
--- a/drivers/media/dvb/dvb-core/dvb_net.c
+++ b/drivers/media/dvb/dvb-core/dvb_net.c
@@ -1052,7 +1052,7 @@
dvb_net_feed_stop(dev);
priv->rx_mode = RX_MODE_UNI;
- spin_lock_bh(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
if (dev->flags & IFF_PROMISC) {
dprintk("%s: promiscuous mode\n", dev->name);
@@ -1077,7 +1077,7 @@
}
}
- spin_unlock_bh(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
dvb_net_feed_start(dev);
}
diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 54161ae..9c5a884 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -2009,7 +2009,7 @@
return 1;
}
-/* Called with rtnl_lock from vlan functions and also dev->xmit_lock
+/* Called with rtnl_lock from vlan functions and also netif_tx_lock
* from set_multicast.
*/
static void
@@ -4252,7 +4252,7 @@
}
#endif
-/* Called with dev->xmit_lock.
+/* Called with netif_tx_lock.
* hard_start_xmit is pseudo-lockless - a lock is only required when
* the tx queue is full. This way, we get the benefit of lockless
* operations most of the time without the complexities to handle
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 55d2367..46326cd 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4191,7 +4191,7 @@
*/
bond_dev->features |= NETIF_F_VLAN_CHALLENGED;
- /* don't acquire bond device's xmit_lock when
+ /* don't acquire bond device's netif_tx_lock when
* transmitting */
bond_dev->features |= NETIF_F_LLTX;
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index feb5b22..5a8651b 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -533,9 +533,9 @@
* critical parts:
* - rx is (pseudo-) lockless: it relies on the single-threading provided
* by the arch code for interrupts.
- * - tx setup is lockless: it relies on dev->xmit_lock. Actual submission
+ * - tx setup is lockless: it relies on netif_tx_lock. Actual submission
* needs dev->priv->lock :-(
- * - set_multicast_list: preparation lockless, relies on dev->xmit_lock.
+ * - set_multicast_list: preparation lockless, relies on netif_tx_lock.
*/
/* in dev: base, irq */
@@ -1213,7 +1213,7 @@
/*
* nv_start_xmit: dev->hard_start_xmit function
- * Called with dev->xmit_lock held.
+ * Called with netif_tx_lock held.
*/
static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
@@ -1407,7 +1407,7 @@
/*
* nv_tx_timeout: dev->tx_timeout function
- * Called with dev->xmit_lock held.
+ * Called with netif_tx_lock held.
*/
static void nv_tx_timeout(struct net_device *dev)
{
@@ -1737,7 +1737,7 @@
* Changing the MTU is a rare event, it shouldn't matter.
*/
nv_disable_irq(dev);
- spin_lock_bh(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
spin_lock(&np->lock);
/* stop engines */
nv_stop_rx(dev);
@@ -1768,7 +1768,7 @@
nv_start_rx(dev);
nv_start_tx(dev);
spin_unlock(&np->lock);
- spin_unlock_bh(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
nv_enable_irq(dev);
}
return 0;
@@ -1803,7 +1803,7 @@
memcpy(dev->dev_addr, macaddr->sa_data, ETH_ALEN);
if (netif_running(dev)) {
- spin_lock_bh(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
spin_lock_irq(&np->lock);
/* stop rx engine */
@@ -1815,7 +1815,7 @@
/* restart rx engine */
nv_start_rx(dev);
spin_unlock_irq(&np->lock);
- spin_unlock_bh(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
} else {
nv_copy_mac_to_hw(dev);
}
@@ -1824,7 +1824,7 @@
/*
* nv_set_multicast: dev->set_multicast function
- * Called with dev->xmit_lock held.
+ * Called with netif_tx_lock held.
*/
static void nv_set_multicast(struct net_device *dev)
{
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 102c1f0..d12605f 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -308,9 +308,9 @@
{
struct sockaddr_ax25 *sa = addr;
- spin_lock_irq(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
- spin_unlock_irq(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
return 0;
}
@@ -767,9 +767,9 @@
break;
}
- spin_lock_irq(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
- spin_unlock_irq(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
err = 0;
break;
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index d81a8e1..3ebbbe5 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -357,9 +357,9 @@
{
struct sockaddr_ax25 *sa = addr;
- spin_lock_irq(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
- spin_unlock_irq(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
return 0;
}
@@ -886,9 +886,9 @@
break;
}
- spin_lock_irq(&dev->xmit_lock);
+ netif_tx_lock_bh(dev);
memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
- spin_unlock_irq(&dev->xmit_lock);
+ netif_tx_unlock_bh(dev);
err = 0;
break;
diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 31fb2d7..2e222ef 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -76,13 +76,13 @@
dp->st_task_enter++;
if ((skb = skb_peek(&dp->tq)) == NULL) {
dp->st_txq_refl_try++;
- if (spin_trylock(&_dev->xmit_lock)) {
+ if (netif_tx_trylock(_dev)) {
dp->st_rxq_enter++;
while ((skb = skb_dequeue(&dp->rq)) != NULL) {
skb_queue_tail(&dp->tq, skb);
dp->st_rx2tx_tran++;
}
- spin_unlock(&_dev->xmit_lock);
+ netif_tx_unlock(_dev);
} else {
/* reschedule */
dp->st_rxq_notenter++;
@@ -110,7 +110,7 @@
}
}
- if (spin_trylock(&_dev->xmit_lock)) {
+ if (netif_tx_trylock(_dev)) {
dp->st_rxq_check++;
if ((skb = skb_peek(&dp->rq)) == NULL) {
dp->tasklet_pending = 0;
@@ -118,10 +118,10 @@
netif_wake_queue(_dev);
} else {
dp->st_rxq_rsch++;
- spin_unlock(&_dev->xmit_lock);
+ netif_tx_unlock(_dev);
goto resched;
}
- spin_unlock(&_dev->xmit_lock);
+ netif_tx_unlock(_dev);
} else {
resched:
dp->tasklet_pending = 1;
diff --git a/drivers/net/irda/vlsi_ir.c b/drivers/net/irda/vlsi_ir.c
index 97a49e0..d70b9e8 100644
--- a/drivers/net/irda/vlsi_ir.c
+++ b/drivers/net/irda/vlsi_ir.c
@@ -959,7 +959,7 @@
|| (now.tv_sec==ready.tv_sec && now.tv_usec>=ready.tv_usec))
break;
udelay(100);
- /* must not sleep here - we are called under xmit_lock! */
+ /* must not sleep here - called under netif_tx_lock! */
}
}
diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index 9062775..2e4eced 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -318,12 +318,12 @@
The rx process only runs in the interrupt handler. Access from outside
the interrupt handler is only permitted after disable_irq().
-The rx process usually runs under the dev->xmit_lock. If np->intr_tx_reap
+The rx process usually runs under the netif_tx_lock. If np->intr_tx_reap
is set, then access is permitted under spin_lock_irq(&np->lock).
Thus configuration functions that want to access everything must call
disable_irq(dev->irq);
- spin_lock_bh(dev->xmit_lock);
+ netif_tx_lock_bh(dev);
spin_lock_irq(&np->lock);
IV. Notes
diff --git a/drivers/net/tulip/winbond-840.c b/drivers/net/tulip/winbond-840.c
index 136a70c..56d86c7 100644
--- a/drivers/net/tulip/winbond-840.c
+++ b/drivers/net/tulip/winbond-840.c
@@ -1605,11 +1605,11 @@
* - get_stats:
* spin_lock_irq(np->lock), doesn't touch hw if not present
* - hard_start_xmit:
- * netif_stop_queue + spin_unlock_wait(&dev->xmit_lock);
+ * synchronize_irq + netif_tx_disable;
* - tx_timeout:
- * netif_device_detach + spin_unlock_wait(&dev->xmit_lock);
+ * netif_device_detach + netif_tx_disable;
* - set_multicast_list
- * netif_device_detach + spin_unlock_wait(&dev->xmit_lock);
+ * netif_device_detach + netif_tx_disable;
* - interrupt handler
* doesn't touch hw if not present, synchronize_irq waits for
* running instances of the interrupt handler.
@@ -1635,11 +1635,10 @@
netif_device_detach(dev);
update_csr6(dev, 0);
iowrite32(0, ioaddr + IntrEnable);
- netif_stop_queue(dev);
spin_unlock_irq(&np->lock);
- spin_unlock_wait(&dev->xmit_lock);
synchronize_irq(dev->irq);
+ netif_tx_disable(dev);
np->stats.rx_missed_errors += ioread32(ioaddr + RxMissed) & 0xffff;
diff --git a/drivers/net/wireless/orinoco.c b/drivers/net/wireless/orinoco.c
index c2d0b09..a5fcfcd 100644
--- a/drivers/net/wireless/orinoco.c
+++ b/drivers/net/wireless/orinoco.c
@@ -1833,7 +1833,9 @@
/* Set promiscuity / multicast*/
priv->promiscuous = 0;
priv->mc_count = 0;
- __orinoco_set_multicast_list(dev); /* FIXME: what about the xmit_lock */
+
+ /* FIXME: what about netif_tx_lock */
+ __orinoco_set_multicast_list(dev);
return 0;
}