[PATCH] target: Make se_dev_check_online() locking IRQ-safe

[PATCH] target: Make se_dev_check_online() locking IRQ-safe

[Roland Dreier]

From: Roland Dreier <roland@purestorage.com>

se_dev_check_online() is called from transport_lookup_cmd_lun(), which
as discussed before may be called from interrupt context.  So it needs
to use spin_lock_irqsave() instead of spin_lock_irq() to avoid
enabling interrupts at the wrong time.

Signed-off-by: Roland Dreier <roland@purestorage.com>
---
 drivers/target/target_core_device.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index fcb8161..f2a4bf2 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -815,12 +815,13 @@ static void se_dev_stop(struct se_device *dev)
 
 int se_dev_check_online(struct se_device *dev)
 {
+	unsigned long flags;
 	int ret;
 
-	spin_lock_irq(&dev->dev_status_lock);
+	spin_lock_irqsave(&dev->dev_status_lock, flags);
 	ret = ((dev->dev_status & TRANSPORT_DEVICE_ACTIVATED) ||
 	       (dev->dev_status & TRANSPORT_DEVICE_DEACTIVATED)) ? 0 : 1;
-	spin_unlock_irq(&dev->dev_status_lock);
+	spin_unlock_irqrestore(&dev->dev_status_lock, flags);
 
 	return ret;
 }

Re: [PATCH] target: Make se_dev_check_online() locking IRQ-safe

[Nicholas A. Bellinger]

On Mon, 2011-06-13 at 20:55 -0700, Roland Dreier wrote:
> From: Roland Dreier <roland@purestorage.com>
> 
> se_dev_check_online() is called from transport_lookup_cmd_lun(), which
> as discussed before may be called from interrupt context.  So it needs
> to use spin_lock_irqsave() instead of spin_lock_irq() to avoid
> enabling interrupts at the wrong time.
> 
> Signed-off-by: Roland Dreier <roland@purestorage.com>

Committed as 91e8524637

Thanks Roland!

--nab

> ---
>  drivers/target/target_core_device.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index fcb8161..f2a4bf2 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -815,12 +815,13 @@ static void se_dev_stop(struct se_device *dev)
>  
>  int se_dev_check_online(struct se_device *dev)
>  {
> +	unsigned long flags;
>  	int ret;
>  
> -	spin_lock_irq(&dev->dev_status_lock);
> +	spin_lock_irqsave(&dev->dev_status_lock, flags);
>  	ret = ((dev->dev_status & TRANSPORT_DEVICE_ACTIVATED) ||
>  	       (dev->dev_status & TRANSPORT_DEVICE_DEACTIVATED)) ? 0 : 1;
> -	spin_unlock_irq(&dev->dev_status_lock);
> +	spin_unlock_irqrestore(&dev->dev_status_lock, flags);
>  
>  	return ret;
>  }
> --
> To unsubscribe from this list: send the line "unsubscribe target-devel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html