avcodec: Do not lock during open for codecs marked as having threadsafe init

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

libavcodec/utils.c

@@ -845,14 +845,14 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
         av_dict_copy(&tmp, *options, 0);
 
     /* If there is a user-supplied mutex locking routine, call it. */
+    if (!(codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE)) {
         if (lockmgr_cb) {
             if ((*lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
                 return -1;
         }
 
         entangled_thread_counter++;
-    if (entangled_thread_counter != 1 &&
-        !(codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE)) {
+        if (entangled_thread_counter != 1) {
             av_log(avctx, AV_LOG_ERROR,
                    "Insufficient thread locking. At least %d threads are "
                    "calling avcodec_open2() at the same time right now.\n",
@@ -860,6 +860,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
             ret = -1;
             goto end;
         }
+    }
 
     avctx->internal = av_mallocz(sizeof(AVCodecInternal));
     if (!avctx->internal) {
@@ -1085,12 +1086,15 @@ FF_ENABLE_DEPRECATION_WARNINGS
 #endif
     }
 end:
+    if (!(codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE)) {
         entangled_thread_counter--;
 
         /* Release any user-supplied mutex. */
         if (lockmgr_cb) {
             (*lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE);
         }
+    }
+
     if (options) {
         av_dict_free(options);
         *options = tmp;