[libcamera-devel] [PATCH 02/10] ipa: add missing thread-safety annotations

[Jacopo Mondi]

Hi Nicholas

On Thu, Oct 27, 2022 at 12:55:07AM -0500, Nicholas Roth via libcamera-devel wrote:
> From: Nicholas Roth <nicholas at rothemail.net>

How come this gets inserted here by git when the commit author and the
sender have the same identity ?

>
> The raspberrypi IPA is missing thread-safety annotations, which breaks
> the build.
>
> Add required thread-safety annotations.
>
> ../src/ipa/raspberrypi/controller/metadata.h:108:31: error: mutex
>   'mutex_' is still held at the end of function [-Werror,-Wthread-safety-analysis]
>         void lock() { mutex_.lock(); }
>                                      ^
> ../src/ipa/raspberrypi/controller/metadata.h:108:23: note: mutex
>   acquired here
>         void lock() { mutex_.lock(); }
>                              ^
> ../src/ipa/raspberrypi/controller/metadata.h:109:25: error: releasing
>   mutex 'mutex_' that was not held [-Werror,-Wthread-safety-analysis]
>         void unlock() { mutex_.unlock(); }
>                                ^

nit: double empty line

>
> Signed-off-by: Nicholas Roth <nicholas at rothemail.net>

I've not followed much the thread annotation thing, but this seems
correct to me, even more so if it silences a compilation error.

Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

> ---
>  src/ipa/raspberrypi/controller/metadata.h | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/src/ipa/raspberrypi/controller/metadata.h b/src/ipa/raspberrypi/controller/metadata.h
> index 0f7ebfaf..870b6e26 100644
> --- a/src/ipa/raspberrypi/controller/metadata.h
> +++ b/src/ipa/raspberrypi/controller/metadata.h
> @@ -13,9 +13,11 @@
>  #include <mutex>
>  #include <string>
>
> +#include <libcamera/base/thread_annotations.h>
> +
>  namespace RPiController {
>
> -class Metadata
> +class LIBCAMERA_TSA_CAPABILITY("mutex") Metadata
>  {
>  public:
>  	Metadata() = default;
> @@ -103,8 +105,8 @@ public:
>  	 * locks with the standard lock classes.
>  	 * e.g. std::lock_guard<RPiController::Metadata> lock(metadata)
>  	 */
> -	void lock() { mutex_.lock(); }
> -	void unlock() { mutex_.unlock(); }
> +	void lock() LIBCAMERA_TSA_ACQUIRE() { mutex_.lock(); }
> +	void unlock() LIBCAMERA_TSA_RELEASE() { mutex_.unlock(); }
>
>  private:
>  	mutable std::mutex mutex_;
> --
> 2.34.1
>