[PATCH] 3c59x: Fix shared IRQ handling

From: Denys Vlasenko
Date: Tue Jul 07 2015 - 14:52:48 EST


As its first order of business, boomerang_interrupt() checks whether
the device really has any pending interrupts. If it does not,
it does nothing and returns, but it still returns IRQ_HANDLED.

This is wrong: interrupt was not handled, IRQ handlers of other
devices sharing this IRQ line need to be called.

vortex_interrupt() has it right: it returns IRQ_NONE in this case
via IRQ_RETVAL(0).

Do the same in boomerang_interrupt().

Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
CC: David S. Miller <davem@xxxxxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
CC: netdev@xxxxxxxxxxxxxxx
---
drivers/net/ethernet/3com/3c59x.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index 41095eb..c11d6fc 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/drivers/net/ethernet/3com/3c59x.c
@@ -2382,6 +2384,7 @@ boomerang_interrupt(int irq, void *dev_id)
void __iomem *ioaddr;
int status;
int work_done = max_interrupt_work;
+ int handled = 0;

ioaddr = vp->ioaddr;

@@ -2400,6 +2403,7 @@ boomerang_interrupt(int irq, void *dev_id)

if ((status & IntLatch) == 0)
goto handler_exit; /* No interrupt: shared IRQs can cause this */
+ handled = 1;

if (status == 0xffff) { /* h/w no longer present (hotplug)? */
if (vortex_debug > 1)
@@ -2501,7 +2505,7 @@ boomerang_interrupt(int irq, void *dev_id)
handler_exit:
vp->handling_irq = 0;
spin_unlock(&vp->lock);
- return IRQ_HANDLED;
+ return IRQ_RETVAL(handled);
}

static int vortex_rx(struct net_device *dev)
--
1.8.1.4

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