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SubjectRe: [PATCH] extcon: Release locking when sending the notification of connector state
+ H. Nikolaus Schaller <hns@goldelico.com>

On 2018년 06월 14일 13:14, Chanwoo Choi wrote:
> Previously, extcon used the spinlock before calling the notifier_call_chain
> to prevent the scheduled out of task and to prevent the notification delay.
> When spinlock is locked for sending the notification, deadlock issue
> occured on the side of extcon consumer device. To fix this issue,
> extcon consumer device should always use the work. it is always not
> reasonable to use work.
>
> To fix this issue on extcon consumer device, release locking when sending
> the notification of connector state.
>
> Fixes: ab11af049f88 ("extcon: Add the synchronization extcon APIs to support the notification")
> Cc: stable@vger.kernel.org
> Cc: Roger Quadros <rogerq@ti.com>
> Cc: Kishon Vijay Abraham I <kishon@ti.com>
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> drivers/extcon/extcon.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index 8bff5fd18185..f75b08a45d4e 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -433,8 +433,8 @@ int extcon_sync(struct extcon_dev *edev, unsigned int id)
> return index;
>
> spin_lock_irqsave(&edev->lock, flags);
> -
> state = !!(edev->state & BIT(index));
> + spin_unlock_irqrestore(&edev->lock, flags);
>
> /*
> * Call functions in a raw notifier chain for the specific one
> @@ -448,6 +448,7 @@ int extcon_sync(struct extcon_dev *edev, unsigned int id)
> */
> raw_notifier_call_chain(&edev->nh_all, state, edev);
>
> + spin_lock_irqsave(&edev->lock, flags);
> /* This could be in interrupt handler */
> prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
> if (!prop_buf) {
>


--
Best Regards,
Chanwoo Choi
Samsung Electronics

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