Re: [PATCH 3/5] logger: reorder prepare_to_wait and mutex_lock

[Dima Zavin]

On Tue, Feb 7, 2012 at 6:30 PM, Tim Bird <tim.bird@xxxxxxxxxxx> wrote:
> If mutex_lock waits, it will return in state TASK_RUNNING,
> rubbing out the effect of prepare_to_wait().
>
> Signed-off-by: Tim Bird <tim.bird@xxxxxxxxxxx>

Acked-by: Dima Zavin <dima@xxxxxxxxxxx>

> ---
>  drivers/staging/android/logger.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c
> index 92cfd94..54b7cdf 100644
> --- a/drivers/staging/android/logger.c
> +++ b/drivers/staging/android/logger.c
> @@ -172,9 +172,10 @@ static ssize_t logger_read(struct file *file, char __user *buf,
>
>  start:
>        while (1) {
> +               mutex_lock(&log->mutex);
> +
>                prepare_to_wait(&log->wq, &wait, TASK_INTERRUPTIBLE);
>
> -               mutex_lock(&log->mutex);
>                ret = (log->w_off == reader->r_off);
>                mutex_unlock(&log->mutex);
>                if (!ret)
> --
> 1.7.2.3
>
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