aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/smc911x.c
diff options
context:
space:
mode:
authorDavid S. Miller <davem@davemloft.net>2008-06-12 05:22:02 -0400
committerDavid S. Miller <davem@davemloft.net>2008-06-12 05:22:02 -0400
commit4bb073c0e32a0862bdb5215d11af19f6c0180c98 (patch)
tree009d95592e3813346c75129bb19d140d393ca913 /drivers/net/smc911x.c
parent7afb380db43ed137b7f67e0e3c3e5afd1ecde730 (diff)
net: Eliminate flush_scheduled_work() calls while RTNL is held.
If the RTNL is held when we invoke flush_scheduled_work() we could deadlock. One such case is linkwatch, it is a work struct which tries to grab the RTNL semaphore. The most common case are net driver ->stop() methods. The simplest conversion is to instead use cancel_{delayed_}work_sync() explicitly on the various work struct the driver uses. This is an OK transformation because these work structs are doing things like resetting the chip, restarting link negotiation, and so forth. And if we're bringing down the device, we're about to turn the chip off and reset it anways. So if we cancel a pending work event, that's fine here. Some drivers were working around this deadlock by using a msleep() polling loop of some sort, and those cases are converted to instead use cancel_{delayed_}work_sync() as well. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/smc911x.c')
-rw-r--r--drivers/net/smc911x.c24
1 files changed, 5 insertions, 19 deletions
diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c
index 4e2800205189..e2ee91a6ae7e 100644
--- a/drivers/net/smc911x.c
+++ b/drivers/net/smc911x.c
@@ -136,7 +136,6 @@ struct smc911x_local {
136 136
137 /* work queue */ 137 /* work queue */
138 struct work_struct phy_configure; 138 struct work_struct phy_configure;
139 int work_pending;
140 139
141 int tx_throttle; 140 int tx_throttle;
142 spinlock_t lock; 141 spinlock_t lock;
@@ -960,11 +959,11 @@ static void smc911x_phy_configure(struct work_struct *work)
960 * We should not be called if phy_type is zero. 959 * We should not be called if phy_type is zero.
961 */ 960 */
962 if (lp->phy_type == 0) 961 if (lp->phy_type == 0)
963 goto smc911x_phy_configure_exit_nolock; 962 return;
964 963
965 if (smc911x_phy_reset(dev, phyaddr)) { 964 if (smc911x_phy_reset(dev, phyaddr)) {
966 printk("%s: PHY reset timed out\n", dev->name); 965 printk("%s: PHY reset timed out\n", dev->name);
967 goto smc911x_phy_configure_exit_nolock; 966 return;
968 } 967 }
969 spin_lock_irqsave(&lp->lock, flags); 968 spin_lock_irqsave(&lp->lock, flags);
970 969
@@ -1033,8 +1032,6 @@ static void smc911x_phy_configure(struct work_struct *work)
1033 1032
1034smc911x_phy_configure_exit: 1033smc911x_phy_configure_exit:
1035 spin_unlock_irqrestore(&lp->lock, flags); 1034 spin_unlock_irqrestore(&lp->lock, flags);
1036smc911x_phy_configure_exit_nolock:
1037 lp->work_pending = 0;
1038} 1035}
1039 1036
1040/* 1037/*
@@ -1356,11 +1353,8 @@ static void smc911x_timeout(struct net_device *dev)
1356 * smc911x_phy_configure() calls msleep() which calls schedule_timeout() 1353 * smc911x_phy_configure() calls msleep() which calls schedule_timeout()
1357 * which calls schedule(). Hence we use a work queue. 1354 * which calls schedule(). Hence we use a work queue.
1358 */ 1355 */
1359 if (lp->phy_type != 0) { 1356 if (lp->phy_type != 0)
1360 if (schedule_work(&lp->phy_configure)) { 1357 schedule_work(&lp->phy_configure);
1361 lp->work_pending = 1;
1362 }
1363 }
1364 1358
1365 /* We can accept TX packets again */ 1359 /* We can accept TX packets again */
1366 dev->trans_start = jiffies; 1360 dev->trans_start = jiffies;
@@ -1531,16 +1525,8 @@ static int smc911x_close(struct net_device *dev)
1531 if (lp->phy_type != 0) { 1525 if (lp->phy_type != 0) {
1532 /* We need to ensure that no calls to 1526 /* We need to ensure that no calls to
1533 * smc911x_phy_configure are pending. 1527 * smc911x_phy_configure are pending.
1534
1535 * flush_scheduled_work() cannot be called because we
1536 * are running with the netlink semaphore held (from
1537 * devinet_ioctl()) and the pending work queue
1538 * contains linkwatch_event() (scheduled by
1539 * netif_carrier_off() above). linkwatch_event() also
1540 * wants the netlink semaphore.
1541 */ 1528 */
1542 while (lp->work_pending) 1529 cancel_work_sync(&lp->phy_configure);
1543 schedule();
1544 smc911x_phy_powerdown(dev, lp->mii.phy_id); 1530 smc911x_phy_powerdown(dev, lp->mii.phy_id);
1545 } 1531 }
1546 1532