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Date: Fri, 29 May 2026 11:42:01 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Maxwell Doose <m32285159@gmail.com>
Cc: Tomasz Duszynski <tomasz.duszynski@octakon.com>, David Lechner
 <dlechner@baylibre.com>, Nuno =?UTF-8?B?U8Oh?= <nuno.sa@analog.com>, Andy
 Shevchenko <andy@kernel.org>, linux-iio@vger.kernel.org (open list:IIO
 SUBSYSTEM AND DRIVERS), linux-kernel@vger.kernel.org (open list)
Subject: Re: [PATCH v5] iio: chemical: scd30: Replace manual locking with
 RAII locking
Message-ID: <20260529114201.4025eeb2@jic23-huawei>
In-Reply-To: <20260528222906.61561-1-m32285159@gmail.com>
References: <20260528222906.61561-1-m32285159@gmail.com>
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On Thu, 28 May 2026 17:29:06 -0500
Maxwell Doose <m32285159@gmail.com> wrote:

> scd30_core.c currently uses manual mutex_lock() and mutex_unlock()
> calls. Replace them with the newer guard(mutex)() for cleaner RAII
> patterns and to improve maintainability.
> 
> Add new helper function scd30_trigger_handler_helper() containing
> the critical section for scd30_trigger_handler().
> 
> In addition, small refactor to replace "?:" operator with regular
> if/else returns.
> 
> Signed-off-by: Maxwell Doose <m32285159@gmail.com>

Looks like you sent a version that won't build.
> +static int scd30_trigger_handler_helper(struct iio_dev *indio_dev, int *scan_data,
> +					size_t scan_data_size)
> +{
> +	struct scd30_state *state = iio_priv(indio_dev);
> +	int ret;
> +
> +	guard(mutex)(&state->lock);
> +
> +	if (!iio_trigger_using_own(indio_dev))
> +		ret = scd30_read_poll(state);
> +	else
> +		ret = scd30_read_meas(state);
> +	memcpy(scan_data, state->meas, scan_data_size);
> +
> +	return ret;
> +}
> +
>  static irqreturn_t scd30_trigger_handler(int irq, void *p)
>  {
>  	struct iio_poll_func *pf = p;
>  	struct iio_dev *indio_dev = pf->indio_dev;
> -	struct scd30_state *state = iio_priv(indio_dev);
>  	struct {
>  		int data[SCD30_MEAS_COUNT];
>  		aligned_s64 ts;
>  	} scan = { };
>  	int ret;
>  
> -	mutex_lock(&state->lock);
> -	if (!iio_trigger_using_own(indio_dev))
> -		ret = scd30_read_poll(state);
> -	else
> -		ret = scd30_read_meas(state);
> -	memcpy(scan.data, state->meas, sizeof(state->meas));
> -	mutex_unlock(&state->lock);
> +	ret = scd30_trigger_handler_helper_locked(indio_dev, scan.data, sizeof(scan.data));
The call needs an update t the new naming.

>  	if (ret)
>  		goto out;
>