[BNX2]: Fix rtnl deadlock in bnx2_close

This fixes an rtnl deadlock problem when flush_scheduled_work() is
called from bnx2_close(). In rare cases, linkwatch_event() may be on
the workqueue from a previous close of a different device and it will
try to get the rtnl lock which is already held by dev_close().

The fix is to set a flag if we are in the reset task which is run
from the workqueue. bnx2_close() will loop until the flag is cleared.
As suggested by Jeff Garzik, the loop is changed to call msleep(1)
instead of yield() in the original patch.

flush_scheduled_work() is also moved to bnx2_remove_one() before the
netdev is freed.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 3a9d6a8b90a2..635a5856102b 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -3975,12 +3975,17 @@ bnx2_reset_task(void *data)
 {
         struct bnx2 *bp = data;
 
+        if (!netif_running(bp->dev))
+                return;
+
+        bp->in_reset_task = 1;
         bnx2_netif_stop(bp);
 
         bnx2_init_nic(bp);
 
         atomic_set(&bp->intr_sem, 1);
         bnx2_netif_start(bp);
+        bp->in_reset_task = 0;
 }
 
 static void
@@ -4172,7 +4177,13 @@ bnx2_close(struct net_device *dev)
         struct bnx2 *bp = dev->priv;
         u32 reset_code;
 
-        flush_scheduled_work();
+        /* Calling flush_scheduled_work() may deadlock because
+         * linkwatch_event() may be on the workqueue and it will try to get
+         * the rtnl_lock which we are holding.
+         */
+        while (bp->in_reset_task)
+                msleep(1);
+
         bnx2_netif_stop(bp);
         del_timer_sync(&bp->timer);
         if (bp->wol)
@@ -5453,6 +5464,8 @@ bnx2_remove_one(struct pci_dev *pdev)
         struct net_device *dev = pci_get_drvdata(pdev);
         struct bnx2 *bp = dev->priv;
 
+        flush_scheduled_work();
+
         unregister_netdev(dev);
 
         if (bp->regview)