drivers/iio/chemical/scd30_core.c | 66 ++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 24 deletions(-)
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>
---
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().
v3:
- Tune up helper to return early on failure condition per Jonathan's
suggestion.
v4:
- Forgot to commit changes listed in v3, now fixed.
v5:
- Remove unneeded comment for scd30_trigger_handler_helper() per
Jonathan's suggestion.
- Change name of arr_size to scan_data_size per Jonathan's suggestion.
- Change type of scan_data_size to size_t per Jonathan's suggestion.
- Added blank line between return and the rest of the function body in
scd30_trigger_handler_helper().
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..20258059f915 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;
}
+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));
if (ret)
goto out;
--
2.54.0Hi Maxwell,
kernel test robot noticed the following build errors:
[auto build test ERROR on jic23-iio/togreg]
[also build test ERROR on linus/master v7.1-rc5 next-20260528]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Maxwell-Doose/iio-chemical-scd30-Replace-manual-locking-with-RAII-locking/20260529-063551
base: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link: https://lore.kernel.org/r/20260528222906.61561-1-m32285159%40gmail.com
patch subject: [PATCH v5] iio: chemical: scd30: Replace manual locking with RAII locking
config: loongarch-randconfig-r071-20260529 (https://download.01.org/0day-ci/archive/20260529/202605292101.GTdtBJA1-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 15.2.0
smatch: v0.5.0-9185-gbcc58b9c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260529/202605292101.GTdtBJA1-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605292101.GTdtBJA1-lkp@intel.com/
All error/warnings (new ones prefixed by >>):
drivers/iio/chemical/scd30_core.c: In function 'scd30_trigger_handler':
>> drivers/iio/chemical/scd30_core.c:617:15: error: implicit declaration of function 'scd30_trigger_handler_helper_locked'; did you mean 'scd30_trigger_handler_helper'? [-Wimplicit-function-declaration]
617 | ret = scd30_trigger_handler_helper_locked(indio_dev, scan.data, sizeof(scan.data));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| scd30_trigger_handler_helper
drivers/iio/chemical/scd30_core.c: At top level:
>> drivers/iio/chemical/scd30_core.c:590:12: warning: 'scd30_trigger_handler_helper' defined but not used [-Wunused-function]
590 | static int scd30_trigger_handler_helper(struct iio_dev *indio_dev, int *scan_data,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +617 drivers/iio/chemical/scd30_core.c
589
> 590 static int scd30_trigger_handler_helper(struct iio_dev *indio_dev, int *scan_data,
591 size_t scan_data_size)
592 {
593 struct scd30_state *state = iio_priv(indio_dev);
594 int ret;
595
596 guard(mutex)(&state->lock);
597
598 if (!iio_trigger_using_own(indio_dev))
599 ret = scd30_read_poll(state);
600 else
601 ret = scd30_read_meas(state);
602 memcpy(scan_data, state->meas, scan_data_size);
603
604 return ret;
605 }
606
607 static irqreturn_t scd30_trigger_handler(int irq, void *p)
608 {
609 struct iio_poll_func *pf = p;
610 struct iio_dev *indio_dev = pf->indio_dev;
611 struct {
612 int data[SCD30_MEAS_COUNT];
613 aligned_s64 ts;
614 } scan = { };
615 int ret;
616
> 617 ret = scd30_trigger_handler_helper_locked(indio_dev, scan.data, sizeof(scan.data));
618 if (ret)
619 goto out;
620
621 iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
622 iio_get_time_ns(indio_dev));
623 out:
624 iio_trigger_notify_done(indio_dev->trig);
625 return IRQ_HANDLED;
626 }
627
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Maxwell,
kernel test robot noticed the following build errors:
[auto build test ERROR on jic23-iio/togreg]
[also build test ERROR on linus/master v7.1-rc5 next-20260528]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Maxwell-Doose/iio-chemical-scd30-Replace-manual-locking-with-RAII-locking/20260529-063551
base: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link: https://lore.kernel.org/r/20260528222906.61561-1-m32285159%40gmail.com
patch subject: [PATCH v5] iio: chemical: scd30: Replace manual locking with RAII locking
config: hexagon-randconfig-r073-20260529 (https://download.01.org/0day-ci/archive/20260529/202605292103.zH0JgWhp-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
smatch: v0.5.0-9185-gbcc58b9c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260529/202605292103.zH0JgWhp-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605292103.zH0JgWhp-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/iio/chemical/scd30_core.c:617:8: error: call to undeclared function 'scd30_trigger_handler_helper_locked'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
617 | ret = scd30_trigger_handler_helper_locked(indio_dev, scan.data, sizeof(scan.data));
| ^
drivers/iio/chemical/scd30_core.c:617:8: note: did you mean 'scd30_trigger_handler_helper'?
drivers/iio/chemical/scd30_core.c:590:12: note: 'scd30_trigger_handler_helper' declared here
590 | static int scd30_trigger_handler_helper(struct iio_dev *indio_dev, int *scan_data,
| ^
1 error generated.
vim +/scd30_trigger_handler_helper_locked +617 drivers/iio/chemical/scd30_core.c
606
607 static irqreturn_t scd30_trigger_handler(int irq, void *p)
608 {
609 struct iio_poll_func *pf = p;
610 struct iio_dev *indio_dev = pf->indio_dev;
611 struct {
612 int data[SCD30_MEAS_COUNT];
613 aligned_s64 ts;
614 } scan = { };
615 int ret;
616
> 617 ret = scd30_trigger_handler_helper_locked(indio_dev, scan.data, sizeof(scan.data));
618 if (ret)
619 goto out;
620
621 iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
622 iio_get_time_ns(indio_dev));
623 out:
624 iio_trigger_notify_done(indio_dev->trig);
625 return IRQ_HANDLED;
626 }
627
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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;
>
On Fri, May 29, 2026 at 5:42 AM Jonathan Cameron <jic23@kernel.org> wrote:
>
> 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.
>
Gah, I don't know how I missed that :/ Will update for v6.
>
> > if (ret)
> > goto out;
> >
>
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