[PATCH v3 2/7] iio: core: Refactor iio_device_claim_direct() implementation

Kurt Borja
2026-01-06T08:07:15Z

In order to eventually unify the locking API, implement
iio_device_claim_direct() fully inline, with the use of
__iio_dev_mode_lock(), which takes care of sparse annotations.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
drivers/iio/industrialio-core.c | 44 -----------------------------------------
include/linux/iio/iio.h | 40 ++++++++++++++++++++++++++-----------
2 files changed, 28 insertions(+), 56 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 34867a860a84..550d100d9cfa 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -2201,50 +2201,6 @@ void __iio_dev_mode_unlock(struct iio_dev *indio_dev)
}
EXPORT_SYMBOL_GPL(__iio_dev_mode_unlock);

-/**
- * __iio_device_claim_direct - Keep device in direct mode
- * @indio_dev: the iio_dev associated with the device
- *
- * If the device is in direct mode it is guaranteed to stay
- * that way until __iio_device_release_direct() is called.
- *
- * Use with __iio_device_release_direct().
- *
- * Drivers should only call iio_device_claim_direct().
- *
- * Returns: true on success, false on failure.
- */
-bool __iio_device_claim_direct(struct iio_dev *indio_dev)
-{
- struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
-
- mutex_lock(&iio_dev_opaque->mlock);
-
- if (iio_buffer_enabled(indio_dev)) {
- mutex_unlock(&iio_dev_opaque->mlock);
- return false;
- }
- return true;
-}
-EXPORT_SYMBOL_GPL(__iio_device_claim_direct);
-
-/**
- * __iio_device_release_direct - releases claim on direct mode
- * @indio_dev: the iio_dev associated with the device
- *
- * Release the claim. Device is no longer guaranteed to stay
- * in direct mode.
- *
- * Drivers should only call iio_device_release_direct().
- *
- * Use with __iio_device_claim_direct()
- */
-void __iio_device_release_direct(struct iio_dev *indio_dev)
-{
- mutex_unlock(&to_iio_dev_opaque(indio_dev)->mlock);
-}
-EXPORT_SYMBOL_GPL(__iio_device_release_direct);
-
/**
* iio_device_claim_buffer_mode - Keep device in buffer mode
* @indio_dev: the iio_dev associated with the device
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index aecda887d833..3cf340208694 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -664,31 +664,47 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);

void __iio_dev_mode_lock(struct iio_dev *indio_dev) __acquires(indio_dev);
void __iio_dev_mode_unlock(struct iio_dev *indio_dev) __releases(indio_dev);
-bool __iio_device_claim_direct(struct iio_dev *indio_dev);
-void __iio_device_release_direct(struct iio_dev *indio_dev);

/*
* Helper functions that allow claim and release of direct mode
* in a fashion that doesn't generate many false positives from sparse.
* Note this must remain static inline in the header so that sparse
- * can see the __acquire() marking. Revisit when sparse supports
- * __cond_acquires()
+ * can see the __acquires() and __releases() markings.
+ */
+
+/**
+ * iio_device_claim_direct - Keep device in direct mode
+ * @indio_dev: the iio_dev associated with the device
+ *
+ * If the device is in direct mode it is guaranteed to stay
+ * that way until iio_device_release_direct() is called.
+ *
+ * Use with iio_device_release_direct().
+ *
+ * Returns: true on success, false on failure.
*/
static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
{
- if (!__iio_device_claim_direct(indio_dev))
- return false;
+ __iio_dev_mode_lock(indio_dev);

- __acquire(iio_dev);
+ if (iio_buffer_enabled(indio_dev)) {
+ __iio_dev_mode_unlock(indio_dev);
+ return false;
+ }

return true;
}

-static inline void iio_device_release_direct(struct iio_dev *indio_dev)
-{
- __iio_device_release_direct(indio_dev);
- __release(indio_dev);
-}
+/**
+ * iio_device_release_direct - Releases claim on direct mode
+ * @indio_dev: the iio_dev associated with the device
+ *
+ * Release the claim. Device is no longer guaranteed to stay
+ * in direct mode.
+ *
+ * Use with iio_device_claim_direct().
+ */
+#define iio_device_release_direct(indio_dev) __iio_dev_mode_unlock(indio_dev)

int iio_device_claim_buffer_mode(struct iio_dev *indio_dev);
void iio_device_release_buffer_mode(struct iio_dev *indio_dev);

--
2.52.0