Bug#595554: [PATCH net-2.6] 3c59x: Fix deadlock in vortex_error()
This fixes a bug introduced in commit
de847272149365363a6043a963a6f42fb91566e2
"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>
---
Dave,
This is the regression I mentioned before. 3c59x should be good after
this.
Ben.
drivers/net/3c59x.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c
index a045559..85671ad 100644
--- a/drivers/net/3c59x.c
+++ b/drivers/net/3c59x.c
@@ -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) {
--
1.7.1
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