linux-kernel - [PATCH v3 2/7] iio: core: Refactor iio_device_claim

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Message-Id: <20260106-lock-impr-v3-2-1db909b192c0@gmail.com>
Date: Tue, 06 Jan 2026 03:06:57 -0500
From: Kurt Borja <kuurtb@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...el.com>, 
 Lars-Peter Clausen <lars@...afoo.de>, 
 Michael Hennerich <Michael.Hennerich@...log.com>, 
 Jonathan Cameron <jic23@...nel.org>, Benson Leung <bleung@...omium.org>, 
 Antoniu Miclaus <antoniu.miclaus@...log.com>, 
 Gwendal Grignou <gwendal@...omium.org>, 
 Shrikant Raskar <raskar.shree97@...il.com>, 
 Per-Daniel Olsson <perdaniel.olsson@...s.com>
Cc: David Lechner <dlechner@...libre.com>, 
 Nuno Sá <nuno.sa@...log.com>, 
 Andy Shevchenko <andy@...nel.org>, Guenter Roeck <groeck@...omium.org>, 
 Jonathan Cameron <Jonathan.Cameron@...wei.com>, linux-iio@...r.kernel.org, 
 linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev, 
 Kurt Borja <kuurtb@...il.com>
Subject: [PATCH v3 2/7] iio: core: Refactor iio_device_claim_direct()
 implementation

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@...il.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