Commit 89b12fab authored Sep 06, 2010 by Ben Hutchings Committed by David S. Miller Sep 07, 2010

3c59x: Fix deadlock in vortex_error()



This fixes a bug introduced in commit
de847272
"3c59x: Use fine-grained locks for MII and windowed register access".

vortex_interrupt() holds vp->window_lock over multiple register
accesses to reduce locking overhead.  However it also needs to call
vortex_error() sometimes, and that uses the regular functions for
access to windowed registers, which will try to acquire window_lock
again.

Therefore, drop window_lock around the call to vortex_error() and set
the window afterward reacquiring the lock.  Since vortex_error() may
call vortex_rx(), which *does* require its caller to hold window_lock,
lift that call up into vortex_interrupt().  This also removes the
potential for calling vortex_rx() on a later-generation NIC.

Reported-and-tested-by: Jens Schüßler <jgs@trash.net> [in Debian's 2.6.32]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1ee89bd0

drivers/net/3c59x.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -1994,10 +1994,9 @@ vortex_error(struct net_device *dev, int status)
		}
		}

		if (status & RxEarly) { /* Rx early is unused. */
		vortex_rx(dev);
		if (status & RxEarly) /* Rx early is unused. */
		iowrite16(AckIntr \| RxEarly, ioaddr + EL3_CMD);
		}

		if (status & StatsFull) { /* Empty statistics. */
		static int DoneDidThat;
		if (vortex_debug > 4)
		@@ -2298,7 +2297,12 @@ vortex_interrupt(int irq, void *dev_id)
		if (status & (HostError \| RxEarly \| StatsFull \| TxComplete \| IntReq)) {
		if (status == 0xffff)
		break;
		if (status & RxEarly)
		vortex_rx(dev);
		spin_unlock(&vp->window_lock);
		vortex_error(dev, status);
		spin_lock(&vp->window_lock);
		window_set(vp, 7);
		}

		if (--work_done < 0) {