From c8656c500dd6e88d427547abe2859213a916a3ea Mon Sep 17 00:00:00 2001
From: stephen hemminger <shemminger@vyatta.com>
Date: Fri, 22 Jul 2011 12:53:56 +0000
Subject: net: allow netif_carrier to be called safely from IRQ

[ Upstream commit 1821f7cd65ad9ea56580b830ac79bf4c4fef59cb ]

As reported by Ben Greer and Froncois Romieu. The code path in
the netif_carrier code leads it to try and disable
a late workqueue to reenable it immediately
netif_carrier_on
-> linkwatch_fire_event
   -> linkwatch_schedule_work
      -> cancel_delayed_work
         -> del_timer_sync

If __cancel_delayed_work is used instead then there is no
problem of waiting for running linkwatch_event.

There is a race between linkwatch_event running re-scheduling
but it is harmless to schedule an extra scan of the linkwatch queue.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 net/core/link_watch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index a7b342131869..357bd4ee4baa 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -126,7 +126,7 @@ static void linkwatch_schedule_work(int urgent)
 		return;
 
 	/* It's already running which is good enough. */
-	if (!cancel_delayed_work(&linkwatch_work))
+	if (!__cancel_delayed_work(&linkwatch_work))
 		return;
 
 	/* Otherwise we reschedule it again for immediate execution. */
-- 
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