[FFmpeg-cvslog] libswscale: Make sws_init_context thread safe.

[Peter Lundblad]

ffmpeg | branch: master | Peter Lundblad <plundblad at google.com> | Wed Apr 28 11:51:23 2021 +0200| [da0abbbb01cae21039e2db028467d0f489c9c9ae] | committer: Michael Niedermayer

libswscale: Make sws_init_context thread safe.

Call ff_sws_rgb2rgb_init via ff_thread_once instead of checking one of the
variables it updates.

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=da0abbbb01cae21039e2db028467d0f489c9c9ae
---

 libswscale/utils.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index 6bac7b658d..d673209d95 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -49,6 +49,7 @@
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
+#include "libavutil/thread.h"
 #include "libavutil/aarch64/cpu.h"
 #include "libavutil/ppc/cpu.h"
 #include "libavutil/x86/asm.h"
@@ -1189,12 +1190,13 @@ av_cold int sws_init_context(SwsContext *c, SwsFilter *srcFilter,
     int ret = 0;
     enum AVPixelFormat tmpFmt;
     static const float float_mult = 1.0f / 255.0f;
+    static AVOnce rgb2rgb_once = AV_ONCE_INIT;
 
     cpu_flags = av_get_cpu_flags();
     flags     = c->flags;
     emms_c();
-    if (!rgb15to16)
-        ff_sws_rgb2rgb_init();
+    if (ff_thread_once(&rgb2rgb_once, ff_sws_rgb2rgb_init) != 0)
+        return AVERROR_UNKNOWN;
 
     unscaled = (srcW == dstW && srcH == dstH);