[PATCH][2.4.23-pre3] fix networking hangs at suspend/resume

[Mikael Pettersson <mikpe@csd.uu.se>]

Since upgrading my laptop from 2.4.23-pre2 to -pre3 it started
hanging hard in conjunction with APM suspend or resume. Typically
the hang occurs after 2-3 suspend/resume cycles.

After two days of working through the 2.4.23-pre2 -> 2.4.23-pre3
patch piece by piece, I traced it to this change:

 > Jeff Garzik:
 >   o [NET] move netif_* helpers from tg3 driver to linux/netdevice.h

A while-test_bit in net/core/dev.c was replaced (indirectly via a
new inline function) by a while-test_and_set_bit. This is not correct
in general, and in this code triggers semi-random hangs at suspend
or resume. I've not seen any hangs at other times, however.

This patch reverts the broken part of the cleanup.

/Mikael

--- linux-2.4.23-pre3/net/core/dev.c.~1~	2003-09-09 02:01:08.000000000 +0200
+++ linux-2.4.23-pre3/net/core/dev.c	2003-09-09 02:02:00.000000000 +0200
@@ -851,7 +851,11 @@
 	 * engine, but this requires more changes in devices. */
 
 	smp_mb__after_clear_bit(); /* Commit netif_running(). */
-	netif_poll_disable(dev);
+	while (test_bit(__LINK_STATE_RX_SCHED, &dev->state)) {
+		/* No hurry. */
+		current->state = TASK_INTERRUPTIBLE;
+		schedule_timeout(1);
+	}
 
 	/*
 	 *	Call the device specific close. This cannot fail.