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([2600:8803:e7e4:500:a950:74e5:81f2:8c89]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7ebcae1dddbsm8558095a34.1.2026.07.11.08.09.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 11 Jul 2026 08:09:53 -0700 (PDT) Message-ID: <0b513d21-31e5-497a-9332-7efc3fd3e010@baylibre.com> Date: Sat, 11 Jul 2026 10:09:51 -0500 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 5/7] iio: dac: ad5686: read_raw/write_raw: use guard(mutex)() To: rodrigo.alencar@analog.com, Michael Auchter , linux@analog.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Cc: Michael Hennerich , Jonathan Cameron , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Philipp Zabel , Kees Cook , "Gustavo A. R. Silva" , Maxwell Doose , Joshua Crofts References: <20260710-ad5686-new-features-v7-0-1bcc8c280e4d@analog.com> <20260710-ad5686-new-features-v7-5-1bcc8c280e4d@analog.com> Content-Language: en-US From: David Lechner In-Reply-To: <20260710-ad5686-new-features-v7-5-1bcc8c280e4d@analog.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 6:20 AM, Rodrigo Alencar via B4 Relay wrote: > From: Rodrigo Alencar > > Use guarded mutex lock to facilitate code review when adding new > attributes. This will allow for early returns, avoiding error-prone > locking and unlocking in error paths. This also adds missing include > linux/cleanup.h. Gain-control support will allow the scale attribute > to be configurable. > > Reviewed-by: Maxwell Doose > Reviewed-by: Joshua Crofts > Signed-off-by: Rodrigo Alencar > --- > drivers/iio/dac/ad5686.c | 19 ++++++++----------- > 1 file changed, 8 insertions(+), 11 deletions(-) > > diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c > index 316f9ccf54d9..df32f46db81e 100644 > --- a/drivers/iio/dac/ad5686.c > +++ b/drivers/iio/dac/ad5686.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -177,11 +178,11 @@ static int ad5686_read_raw(struct iio_dev *indio_dev, > struct ad5686_state *st = iio_priv(indio_dev); > int ret; > > + guard(mutex)(&st->lock); The commit message should explain why the location we are taking the lock has moved. Although, I don't see a reason to move it. > + > switch (m) { > case IIO_CHAN_INFO_RAW: > - mutex_lock(&st->lock); > ret = ad5686_read(st, chan->address); > - mutex_unlock(&st->lock); > if (ret < 0) > return ret; > *val = (ret >> chan->scan_type.shift) & > @@ -202,23 +203,19 @@ static int ad5686_write_raw(struct iio_dev *indio_dev, > long mask) > { > struct ad5686_state *st = iio_priv(indio_dev); > - int ret; > + > + guard(mutex)(&st->lock); > > switch (mask) { > case IIO_CHAN_INFO_RAW: > if (val >= (1 << chan->scan_type.realbits) || val < 0) > return -EINVAL; > > - mutex_lock(&st->lock); > - ret = ad5686_write(st, AD5686_CMD_WRITE_INPUT_N_UPDATE_N, > - chan->address, val << chan->scan_type.shift); > - mutex_unlock(&st->lock); > - break; > + return ad5686_write(st, AD5686_CMD_WRITE_INPUT_N_UPDATE_N, > + chan->address, val << chan->scan_type.shift); > default: > - ret = -EINVAL; > + return -EINVAL; > } > - > - return ret; > } > > static const struct iio_info ad5686_info = { >