avutil/hwcontext_qsv: Allocate public and priv device hwctx together

This is possible because the lifetime of both coincide.
Besides reducing the number of allocations this also simplifies
access to QSVDeviceContext as one no longer has to
go through AVHWDeviceInternal.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/hwcontext_qsv.c

@@ -70,6 +70,11 @@ typedef struct QSVDevicePriv {
 } QSVDevicePriv;
 
 typedef struct QSVDeviceContext {
+    /**
+     * The public AVQSVDeviceContext. See hwcontext_qsv.h for it.
+     */
+    AVQSVDeviceContext p;
+
     mfxHDL              handle;
     mfxHandleType       handle_type;
     mfxVersion          ver;
@@ -268,8 +273,8 @@ static int qsv_fill_border(AVFrame *dst, const AVFrame *src)
 
 static int qsv_device_init(AVHWDeviceContext *ctx)
 {
-    AVQSVDeviceContext *hwctx = ctx->hwctx;
-    QSVDeviceContext       *s = ctx->internal->priv;
+    QSVDeviceContext       *s = ctx->hwctx;
+    AVQSVDeviceContext *hwctx = &s->p;
     int   hw_handle_supported = 0;
     mfxHandleType handle_type;
     enum AVHWDeviceType device_type;
@@ -378,7 +383,7 @@ static int qsv_init_child_ctx(AVHWFramesContext *ctx)
 {
     AVQSVFramesContext     *hwctx = ctx->hwctx;
     QSVFramesContext           *s = ctx->internal->priv;
-    QSVDeviceContext *device_priv = ctx->device_ctx->internal->priv;
+    QSVDeviceContext *device_priv = ctx->device_ctx->hwctx;
 
     AVBufferRef *child_device_ref = NULL;
     AVBufferRef *child_frames_ref = NULL;
@@ -1108,7 +1113,8 @@ static int qsv_init_internal_session(AVHWFramesContext *ctx,
                                      mfxSession *session, int upload)
 {
     AVQSVFramesContext *frames_hwctx = ctx->hwctx;
-    QSVDeviceContext   *device_priv  = ctx->device_ctx->internal->priv;
+    QSVDeviceContext   *device_priv  = ctx->device_ctx->hwctx;
+    AVQSVDeviceContext *hwctx        = &device_priv->p;
     int opaque = 0;
 
     mfxFrameAllocator frame_allocator = {
@@ -1123,7 +1129,6 @@ static int qsv_init_internal_session(AVHWFramesContext *ctx,
     mfxVideoParam par;
     mfxStatus err;
     int                   ret = AVERROR_UNKNOWN;
-    AVQSVDeviceContext *hwctx = ctx->device_ctx->hwctx;
     /* hwctx->loader is non-NULL for oneVPL user and NULL for non-oneVPL user */
     void             **loader = &hwctx->loader;
 
@@ -2246,8 +2251,7 @@ const HWContextType ff_hwcontext_type_qsv = {
     .type                   = AV_HWDEVICE_TYPE_QSV,
     .name                   = "QSV",
 
-    .device_hwctx_size      = sizeof(AVQSVDeviceContext),
-    .device_priv_size       = sizeof(QSVDeviceContext),
+    .device_hwctx_size      = sizeof(QSVDeviceContext),
     .frames_hwctx_size      = sizeof(AVQSVFramesContext),
     .frames_priv_size       = sizeof(QSVFramesContext),