[FFmpeg-devel] [PATCH 2/4] lavfi/avfilter: simplify filter registration

[Rostislav Pehlivanov]

On 29 November 2017 at 16:40, Michael Niedermayer <michael at niedermayer.cc>
wrote:

> On Wed, Nov 29, 2017 at 03:51:34AM +0000, Rostislav Pehlivanov wrote:
> > On 28 November 2017 at 20:23, Michael Niedermayer <michael at niedermayer.cc
> >
> > wrote:
> >
> > > On Mon, Nov 27, 2017 at 04:30:19AM +0000, Rostislav Pehlivanov wrote:
> > > > Atomics were entirely pointless and did nothing but slow and
> complicate
> > > > the process down. This could be improved further still but the main
> > > > objective of this commit is to simplify.
> > > >
> > > > Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
> > > > ---
> > > >  libavfilter/avfilter.c | 8 +++++---
> > > >  1 file changed, 5 insertions(+), 3 deletions(-)
> > >
> > > *_register() can be called by the user app in a unsyncronized way
> > > for example from a module like vlc used AFAIK.
> > > or from libs loaded by an application which use libavfilter or other
> > > internally.
> > >
> > > These registration functions should stay thread safe
> > >
> > >
> > > [...]
> > >
> > > --
> > > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC7
> 87040B0FAB
> > >
> > > Those who would give up essential Liberty, to purchase a little
> > > temporary Safety, deserve neither Liberty nor Safety -- Benjamin
> Franklin
> > >
> > > _______________________________________________
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> > > ffmpeg-devel at ffmpeg.org
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> > >
> > >
> > What variable actually needs to be protected?
>
> The linked list of registered "entities"
> That is if the addition is not synchronized by some means, an atomic
> exchange a mutex or something then a race can generally occur
> and only one addition might succeed or something else might get
> entangled
>
> This is in practical terms a very unlikely event to occur of course
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> You can kill me, but you cannot change the truth.
>
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>
Could you test the attached patch? Pretty much everything is synchronized.
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