[PATCH AUTOSEL for 4.14 068/100] net: dsa: mv88e6xxx: Fix interrupt masking on removal

Sasha Levin
2018-01-28T23:03:44Z

From: Andrew Lunn <andrew@lunn.ch>

[ Upstream commit 3d5fdba1842bdd2eef29364c660558cb4cbb3fe0 ]

When removing the interrupt handling code, we should mask the
generation of interrupts. The code however unmasked all
interrupts. This can then cause a new interrupt. We then get into a
deadlock where the interrupt thread is waiting to run, and the code
continues, trying to remove the interrupt handler, which means waiting
for the thread to complete. On a UP machine this deadlocks.

Fix so we really mask interrupts in the hardware. The same error is
made in the error path when install the interrupt handling code.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/net/dsa/mv88e6xxx/chip.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index d74c7335c512..07704b372861 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -339,7 +339,7 @@ static void mv88e6xxx_g1_irq_free(struct mv88e6xxx_chip *chip)
u16 mask;

mv88e6xxx_g1_read(chip, MV88E6XXX_G1_CTL1, &mask);
- mask |= GENMASK(chip->g1_irq.nirqs, 0);
+ mask &= ~GENMASK(chip->g1_irq.nirqs, 0);
mv88e6xxx_g1_write(chip, MV88E6XXX_G1_CTL1, mask);

free_irq(chip->irq, chip);
@@ -395,7 +395,7 @@ static int mv88e6xxx_g1_irq_setup(struct mv88e6xxx_chip *chip)
return 0;

out_disable:
- mask |= GENMASK(chip->g1_irq.nirqs, 0);
+ mask &= ~GENMASK(chip->g1_irq.nirqs, 0);
mv88e6xxx_g1_write(chip, MV88E6XXX_G1_CTL1, mask);

out_mapping:
--
2.11.0