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

[Kieran Bingham]

Hi Nicholas,

Quoting Jacopo Mondi via libcamera-devel (2022-10-27 17:08:33)
> 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>

These tags are valuable to you. We desire two Reviewed-by (or Acked-by:)
tags to get a patch merged.

So when you're given one, please add it to your patch so that it gets
included when you repost a later version.

I also think this patch is good, but I'll add my tag to the latest
version, however in this instance - because it's under
src/ipa/raspberrypi/ - we'll want an ack from RPi too.

--
Kieran


> 
> > ---
> >  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
> >