[PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c6678aa9b4ef..e7ff7483d2fb 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
 	if (chip->irq > 0) {
 		if (chip->info->g2_irqs > 0)
 			mv88e6xxx_g2_irq_free(chip);
+		mutex_lock(&chip->reg_lock);
 		mv88e6xxx_g1_irq_free(chip);
+		mutex_unlock(&chip->reg_lock);
 	}
 }
 

-- 
2.14.1

On 09/26/2017 11:57 AM, Vivien Didelot wrote:

mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <redacted>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

From: Vivien Didelot

Isn't the irq_free code likely to have to sleep waiting for any
ISR to complete??

	David

On Wed, Sep 27, 2017 at 09:06:01AM +0000, David Laight wrote:

From: Vivien Didelot

quoted

Sent: 26 September 2017 19:57
mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c6678aa9b4ef..e7ff7483d2fb 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
 	if (chip->irq > 0) {
 		if (chip->info->g2_irqs > 0)
 			mv88e6xxx_g2_irq_free(chip);
+		mutex_lock(&chip->reg_lock);
 		mv88e6xxx_g1_irq_free(chip);
+		mutex_unlock(&chip->reg_lock);

Isn't the irq_free code likely to have to sleep waiting for any
ISR to complete??

Hi David

Possibly. But this is a mutex, not a spinlock. So sleeping is O.K.
Or am i missing something?

	  Andrew

From: Andrew Lunn

Sent: 27 September 2017 14:07
To: David Laight
On Wed, Sep 27, 2017 at 09:06:01AM +0000, David Laight wrote:

quoted

From: Vivien Didelot

quoted

Sent: 26 September 2017 19:57
mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c6678aa9b4ef..e7ff7483d2fb 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
 	if (chip->irq > 0) {
 		if (chip->info->g2_irqs > 0)
 			mv88e6xxx_g2_irq_free(chip);
+		mutex_lock(&chip->reg_lock);
 		mv88e6xxx_g1_irq_free(chip);
+		mutex_unlock(&chip->reg_lock);

Isn't the irq_free code likely to have to sleep waiting for any
ISR to complete??

Hi David

Possibly. But this is a mutex, not a spinlock. So sleeping is O.K.
Or am i missing something?

Looks like I was missing some coffee :-)

	David

From: Vivien Didelot <redacted>
Date: Tue, 26 Sep 2017 14:57:21 -0400

mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <redacted>

Applied and queued up for -stable.