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([2600:8803:e7e4:500:6b05:aad2:5053:6d1]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-3f0dca3ad8asm11031494fac.6.2025.12.03.13.52.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Dec 2025 13:52:44 -0800 (PST) Message-ID: Date: Wed, 3 Dec 2025 15:52:43 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 5/6] iio: health: max30102: Use cleanup.h for IIO locks To: Kurt Borja , Andy Shevchenko , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , Benson Leung , Antoniu Miclaus , Gwendal Grignou , Shrikant Raskar , Per-Daniel Olsson Cc: =?UTF-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , Guenter Roeck , Jonathan Cameron , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev References: <20251203-lock-impr-v1-0-b4a1fd639423@gmail.com> <20251203-lock-impr-v1-5-b4a1fd639423@gmail.com> Content-Language: en-US From: David Lechner In-Reply-To: <20251203-lock-impr-v1-5-b4a1fd639423@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/3/25 1:18 PM, Kurt Borja wrote: > Simplify and drop "hacky" busy-waiting code in max30102_read_raw() by > using scoped_guard(). > > Signed-off-by: Kurt Borja > --- > drivers/iio/health/max30102.c | 24 +++++++----------------- > 1 file changed, 7 insertions(+), 17 deletions(-) > > diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c > index 678720102f2b..c642842cb5fb 100644 > --- a/drivers/iio/health/max30102.c > +++ b/drivers/iio/health/max30102.c > @@ -24,6 +24,7 @@ > #include > #include > #include > +#include > > #define MAX30102_DRV_NAME "max30102" > #define MAX30102_PART_NUMBER 0x15 > @@ -468,6 +469,7 @@ static int max30102_read_raw(struct iio_dev *indio_dev, > { > struct max30102_data *data = iio_priv(indio_dev); > int ret = -EINVAL; > + bool direct_en; > > switch (mask) { > case IIO_CHAN_INFO_RAW: > @@ -475,25 +477,13 @@ static int max30102_read_raw(struct iio_dev *indio_dev, > * Temperature reading can only be acquired when not in > * shutdown; leave shutdown briefly when buffer not running > */ > -any_mode_retry: > - if (!iio_device_claim_buffer(indio_dev)) { > - /* > - * This one is a *bit* hacky. If we cannot claim buffer > - * mode, then try direct mode so that we make sure > - * things cannot concurrently change. And we just keep > - * trying until we get one of the modes... > - */ > - if (!iio_device_claim_direct(indio_dev)) > - goto any_mode_retry; > + scoped_guard(iio_device_claim, indio_dev) { scoped_guard() is sketchy in switch statements because there is a hidden for loop. If someone came along later and put a break; inside of the scope, it would break out of the hidden for loop rather than the apparent switch case! Besides that, it adds extra indent that we could avoid. > + direct_en = !iio_buffer_enabled(indio_dev); > > - ret = max30102_get_temp(data, val, true); > - iio_device_release_direct(indio_dev); > - } else { > - ret = max30102_get_temp(data, val, false); > - iio_device_release_buffer(indio_dev); > + ret = max30102_get_temp(data, val, direct_en); > + if (ret) > + return ret; > } > - if (ret) > - return ret; > > ret = IIO_VAL_INT; > break; > I would write the whole function like this: static int max30102_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct max30102_data *data = iio_priv(indio_dev); int ret; switch (mask) { case IIO_CHAN_INFO_RAW: { /* * Temperature reading can only be acquired when not in * shutdown; leave shutdown briefly when buffer not running */ guard(iio_device_claim)(indio_dev); ret = max30102_get_temp(data, val, !iio_buffer_enabled(indio_dev)); if (ret) return ret; return IIO_VAL_INT; } case IIO_CHAN_INFO_SCALE: *val = 1000; /* 62.5 */ *val2 = 16; return IIO_VAL_FRACTIONAL; default: return -EINVAL; } } Could also simplify things further by moving the call to iio_buffer_enabled() into max30102_get_temp().