Re: [PATCH v4 2/9] iio: core: annotate the conditional mode claims

[Jonathan Cameron]

On Tue, 27 Oct 2026 14:49:47 +0200
Rupesh Majhi <zoone.rupert@xxxxxxxxx> wrote:

> iio_device_claim_direct() and iio_device_try_claim_buffer_mode() hold
> the mode lock only when they return true, but carry no annotation. With
> context analysis on, each caller that releases the claim is reported
> for releasing a lock it never took.
> 
> Mark both __cond_acquires(true, indio_dev), the token that
> __iio_dev_mode_lock() acquires. Sparse no longer reads these
> annotations, so drop the comment about it.
Hi Rupesh,

The history of the definitions of these being in the header at
all was to make them visible enough to sparse that it could
figure out the locking and 'mostly' give good coverage.

Given that's no longer necessary, maybe it makes sense to make
the implementations private. It doesn't really help us that
much as those nasty helpers are still needed for the
rarely used guard that claims the current mode.

So maybe it's worth this maybe not...  Anyhow, perhaps one for
another day given I don't think it helps this effort.

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index e9a5d1d905c1..04c194bdda87 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -2269,6 +2269,33 @@ void __iio_dev_mode_unlock(struct iio_dev *indio_dev)
 }
 EXPORT_SYMBOL_GPL(__iio_dev_mode_unlock);
 
+bool iio_device_claim_direct(struct iio_dev *indio_dev)
+{
+       __iio_dev_mode_lock(indio_dev);
+
+       if (iio_buffer_enabled(indio_dev)) {
+               __iio_dev_mode_unlock(indio_dev);
+               return false;
+       }
+
+       return true;
+}
+EXPORT_SYMBOL_GPL(iio_device_claim_direct);
+
+bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
+       __cond_acquires(true, indio_dev)
+{
+       __iio_dev_mode_lock(indio_dev);
+
+       if (!iio_buffer_enabled(indio_dev)) {
+               __iio_dev_mode_unlock(indio_dev);
+               return false;
+       }
+
+       return true;
+}
+EXPORT_SYMBOL_GPL(iio_device_try_claim_buffer_mode);
+
 /**
  * iio_device_get_current_mode() - helper function providing read-only access to
  *                                the opaque @currentmode variable
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index ca91f5a64626..b9e4888e18bc 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -718,18 +718,7 @@ void __iio_dev_mode_unlock(struct iio_dev *indio_dev) __releases(indio_dev);
  *
  * Returns: true on success, false on failure.
  */
-static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
-       __cond_acquires(true, indio_dev)
-{
-       __iio_dev_mode_lock(indio_dev);
-
-       if (iio_buffer_enabled(indio_dev)) {
-               __iio_dev_mode_unlock(indio_dev);
-               return false;
-       }
-
-       return true;
-}
+bool iio_device_claim_direct(struct iio_dev *indio_dev) __cond_acquires(true, indio_dev);
 
 /**
  * iio_device_release_direct() - Releases claim on direct mode
@@ -753,18 +742,8 @@ static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
  *
  * Returns: true on success, false on failure.
  */
-static inline bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
-       __cond_acquires(true, indio_dev)
-{
-       __iio_dev_mode_lock(indio_dev);
-
-       if (!iio_buffer_enabled(indio_dev)) {
-               __iio_dev_mode_unlock(indio_dev);
-               return false;
-       }
-
-       return true;
-}
+bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
+  __cond_acquires(true, indio_dev);
 
 /**
  * iio_device_release_buffer_mode() - releases claim on buffer mode


> 
> Signed-off-by: Rupesh Majhi <zoone.rupert@xxxxxxxxx>
> ---
> Cc: Marco Elver <elver@xxxxxxxxxx>
> Cc: Bart Van Assche <bvanassche@xxxxxxx>
> 
>  include/linux/iio/iio.h | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 9b63785d5aec..ca91f5a64626 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -707,13 +707,6 @@ 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);
>  
> -/*
> - * 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 __acquires() and __releases() annotations.
> - */
> -
>  /**
>   * iio_device_claim_direct() - Keep device in direct mode
>   * @indio_dev:	the iio_dev associated with the device
> @@ -726,6 +719,7 @@ void __iio_dev_mode_unlock(struct iio_dev *indio_dev) __releases(indio_dev);
>   * Returns: true on success, false on failure.
>   */
>  static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
> +	__cond_acquires(true, indio_dev)
>  {
>  	__iio_dev_mode_lock(indio_dev);
>  
> @@ -760,6 +754,7 @@ static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
>   * Returns: true on success, false on failure.
>   */
>  static inline bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
> +	__cond_acquires(true, indio_dev)
>  {
>  	__iio_dev_mode_lock(indio_dev);
>