Re: [PATCH] iio: frequency: adf4377: replace mutex_lock/unlock with guard and scoped_guard

[Jonathan Cameron <jic23@kernel.org>]

On Wed,  6 May 2026 11:43:59 -0300
Educg550 <educg550@usp.br> wrote:

> From: Eduardo Guedes <educg550@usp.br>

Read submitting patches, particularly about how to send a v2.
Should be [PATCH V2]
> 
> Replace manual mutex_lock()/mutex_unlock() calls with guard(mutex) and
> scoped_guard(mutex) from cleanup.h.
> 
> Using guard(mutex) and scoped_guard(mutex) from cleanup.h allows the
Andy pointed out in another review earlier that it would be clearer to
refer to guard(mutex)()

For scoped_guard() if it were used I'd use scoped_guard(mutex, ...)
to refer to it.

> compiler to enforce lock release on every exit path, eliminating the
> error-prone manual lock/unlock pattern and the goto-based exit labels
> that existed in adf4377_get_freq() and adf4377_set_freq(). This reduces
> the chance of lock imbalance bugs.
> 
> Signed-off-by: Eduardo Guedes <educg550@usp.br>
> Co-developed-by: Lucca Ciriac <luccaciriac@usp.br>
> Signed-off-by: Lucca Ciriac <luccaciriac@usp.br>
> ---

There should be a change log here.  Otherwise just one trivial
request inline for v3.

>  drivers/iio/frequency/adf4377.c | 80 +++++++++++++++------------------
>  1 file changed, 35 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/iio/frequency/adf4377.c b/drivers/iio/frequency/adf4377.c
> index ff6077e29..f91b9c6e2 100644
> --- a/drivers/iio/frequency/adf4377.c
> +++ b/drivers/iio/frequency/adf4377.c

>  static void adf4377_gpio_init(struct adf4377_state *st)
> @@ -919,13 +912,10 @@ static int adf4377_properties_parse(struct adf4377_state *st)
>  static int adf4377_freq_change(struct notifier_block *nb, unsigned long action, void *data)
>  {
>  	struct adf4377_state *st = container_of(nb, struct adf4377_state, nb);
> -	int ret;
>  
>  	if (action == POST_RATE_CHANGE) {
> -		mutex_lock(&st->lock);
> -		ret = notifier_from_errno(adf4377_init(st));
> -		mutex_unlock(&st->lock);
> -		return ret;
> +		guard(mutex)(&st->lock);

Slight preference for a blank line here as the we don't have the same need
for closely associating lock and action as we did with the original code.

> +		return notifier_from_errno(adf4377_init(st));
>  	}
>  
>  	return NOTIFY_OK;