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[23.88.128.2]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-43a957b84fdsm7146229fac.18.2026.05.19.06.19.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 06:19:45 -0700 (PDT) From: Maxwell Doose To: jic23@kernel.org Cc: Tomasz Duszynski , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko , linux-iio@vger.kernel.org (open list:IIO SUBSYSTEM AND DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2] iio: chemical: scd30: Replace manual locking with RAII locking Date: Tue, 19 May 2026 08:19:43 -0500 Message-ID: <20260519131944.25174-1-m32285159@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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_locked() 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 --- v2: - Fix callback issue as noted by Jonathan v1. - Refactor critical section of scd30_trigger_handler() into helper called scd30_trigger_handler_helper_locked(). - Revert removal of goto in scd30_trigger_handler(). drivers/iio/chemical/scd30_core.c | 66 ++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 24 deletions(-) diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c index a665fcb78806..bb8bdea7c833 100644 --- a/drivers/iio/chemical/scd30_core.c +++ b/drivers/iio/chemical/scd30_core.c @@ -368,11 +368,13 @@ static ssize_t calibration_auto_enable_show(struct device *dev, struct device_at int ret; u16 val; - mutex_lock(&state->lock); - ret = scd30_command_read(state, CMD_ASC, &val); - mutex_unlock(&state->lock); + guard(mutex)(&state->lock); - return ret ?: sysfs_emit(buf, "%d\n", val); + ret = scd30_command_read(state, CMD_ASC, &val); + if (ret) + return ret; + + return sysfs_emit(buf, "%d\n", val); } static ssize_t calibration_auto_enable_store(struct device *dev, struct device_attribute *attr, @@ -387,11 +389,13 @@ static ssize_t calibration_auto_enable_store(struct device *dev, struct device_a if (ret) return ret; - mutex_lock(&state->lock); - ret = scd30_command_write(state, CMD_ASC, val); - mutex_unlock(&state->lock); + guard(mutex)(&state->lock); - return ret ?: len; + ret = scd30_command_write(state, CMD_ASC, val); + if (ret) + return ret; + + return len; } static ssize_t calibration_forced_value_show(struct device *dev, struct device_attribute *attr, @@ -402,11 +406,13 @@ static ssize_t calibration_forced_value_show(struct device *dev, struct device_a int ret; u16 val; - mutex_lock(&state->lock); - ret = scd30_command_read(state, CMD_FRC, &val); - mutex_unlock(&state->lock); + guard(mutex)(&state->lock); - return ret ?: sysfs_emit(buf, "%d\n", val); + ret = scd30_command_read(state, CMD_FRC, &val); + if (ret) + return ret; + + return sysfs_emit(buf, "%d\n", val); } static ssize_t calibration_forced_value_store(struct device *dev, struct device_attribute *attr, @@ -424,11 +430,13 @@ static ssize_t calibration_forced_value_store(struct device *dev, struct device_ if (val < SCD30_FRC_MIN_PPM || val > SCD30_FRC_MAX_PPM) return -EINVAL; - mutex_lock(&state->lock); - ret = scd30_command_write(state, CMD_FRC, val); - mutex_unlock(&state->lock); + guard(mutex)(&state->lock); - return ret ?: len; + ret = scd30_command_write(state, CMD_FRC, val); + if (ret) + return ret; + + return len; } static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0); @@ -579,24 +587,34 @@ static irqreturn_t scd30_irq_thread_handler(int irq, void *priv) return IRQ_HANDLED; } +/* Meant ONLY for scd30_trigger_handler() */ +static int scd30_trigger_handler_helper_locked(struct iio_dev *indio_dev, + int *scan_data, int arr_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, arr_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)); if (ret) goto out; -- 2.54.0