[2/2] extcon: Fix extcon_cable_get_state() from getting old state after notification
diff mbox

Message ID 1436194018-18696-3-git-send-email-rogerq@ti.com
State New
Headers show

Commit Message

Roger Quadros July 6, 2015, 2:46 p.m. UTC
Currently the extcon code notifiers the interested listeners
before it updates the extcon state with the new state.
This will cause the listeners that use extcon_cable_get_state()
to get the stale state and loose the new state.

Fix this by first changing the extcon state variable and then
notifying listeners.

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/extcon/extcon.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

Chanwoo Choi July 31, 2015, 6:38 a.m. UTC | #1
Hi Roger,

On 07/06/2015 11:46 PM, Roger Quadros wrote:
> Currently the extcon code notifiers the interested listeners
> before it updates the extcon state with the new state.
> This will cause the listeners that use extcon_cable_get_state()
> to get the stale state and loose the new state.
> 
> Fix this by first changing the extcon state variable and then
> notifying listeners.
> 
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/extcon/extcon.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)

Applied it.

Thanks,
Chanwoo Choi

> 
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index 868c6e2..26d1e1e 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -275,19 +275,25 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
>  	spin_lock_irqsave(&edev->lock, flags);
>  
>  	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
> +		u32 old_state;
> +
>  		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
>  						   (state & mask))) {
>  			spin_unlock_irqrestore(&edev->lock, flags);
>  			return -EPERM;
>  		}
>  
> +		old_state = edev->state;
> +		edev->state &= ~mask;
> +		edev->state |= state & mask;
> +
>  		for (index = 0; index < edev->max_supported; index++) {
> -			if (is_extcon_changed(edev->state, state, index, &attached))
> -				raw_notifier_call_chain(&edev->nh[index], attached, edev);
> +			if (is_extcon_changed(old_state, edev->state, index,
> +					      &attached))
> +				raw_notifier_call_chain(&edev->nh[index],
> +							attached, edev);
>  		}
>  
> -		edev->state &= ~mask;
> -		edev->state |= state & mask;
>  
>  		/* This could be in interrupt handler */
>  		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
> 

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Patch
diff mbox

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 868c6e2..26d1e1e 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -275,19 +275,25 @@  int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 	spin_lock_irqsave(&edev->lock, flags);
 
 	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
+		u32 old_state;
+
 		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
 						   (state & mask))) {
 			spin_unlock_irqrestore(&edev->lock, flags);
 			return -EPERM;
 		}
 
+		old_state = edev->state;
+		edev->state &= ~mask;
+		edev->state |= state & mask;
+
 		for (index = 0; index < edev->max_supported; index++) {
-			if (is_extcon_changed(edev->state, state, index, &attached))
-				raw_notifier_call_chain(&edev->nh[index], attached, edev);
+			if (is_extcon_changed(old_state, edev->state, index,
+					      &attached))
+				raw_notifier_call_chain(&edev->nh[index],
+							attached, edev);
 		}
 
-		edev->state &= ~mask;
-		edev->state |= state & mask;
 
 		/* This could be in interrupt handler */
 		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);