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[FFmpeg-devel,v3,1/1] avutils/hwcontext: When deriving a hwdevice, search for existing device in both directions

Message ID MN2PR04MB59811CB97785EFBA065CF05ABAB59@MN2PR04MB5981.namprd04.prod.outlook.com
State New
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Series [FFmpeg-devel,v3,1/1] avutils/hwcontext: When deriving a hwdevice, search for existing device in both directions
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Commit Message

Soft Works Oct. 11, 2021, 4:19 a.m. UTC
The test /libavutil/tests/hwdevice checks that when deriving a device
from a source device and then deriving back to the type of the source
device, the result is matching the original source device, i.e. the
derivation mechanism doesn't create a new device in this case.

Previously, this test was usually passed, but only due to two different
kind of flaws:

1. The test covers only a single level of derivation (and back)

It derives device Y from device X and then Y back to the type of X and
checks whether the result matches X.

What it doesn't check for, are longer chains of derivation like:

CUDA1 > OpenCL2 > CUDA3 and then back to OpenCL4

In that case, the second derivation returns the first device (CUDA3 ==
CUDA1), but when deriving OpenCL4, hwcontext.c was creating a new
OpenCL4 context instead of returning OpenCL2, because there was no link
from CUDA1 to OpenCL2 (only backwards from OpenCL2 to CUDA1)

If the test would check for two levels of derivation, it would have
failed.

This patch fixes those (yet untested) cases by introducing forward
references (derived_device) in addition to the existing back references
(source_device).

2. hwcontext_qsv didn't properly set the source_device

In case of QSV, hwcontext_qsv creates a source context internally
(vaapi, dxva2 or d3d11va) without calling av_hwdevice_ctx_create_derived
and without setting source_device.

This way, the hwcontext test ran successful, but what practically
happened, was that - for example - deriving vaapi from qsv didn't return
the original underlying vaapi device and a new one was created instead:
Exactly what the test is intended to detect and prevent. It just
couldn't do so, because the original device was hidden (= not set as the
source_device of the QSV device).

This patch properly makes these setting and fixes all derivation
scenarios.

(at a later stage, /libavutil/tests/hwdevice should be extended to check
longer derivation chains as well)

Signed-off-by: softworkz <softworkz@hotmail.com>
---
v3: avoid double-release as suggested by Haihao

 libavutil/hwcontext.c          | 38 ++++++++++++++++++++++++++++++++++
 libavutil/hwcontext.h          |  1 +
 libavutil/hwcontext_internal.h |  6 ++++++
 libavutil/hwcontext_qsv.c      | 16 ++++++++++----
 4 files changed, 57 insertions(+), 4 deletions(-)

Comments

Xiang, Haihao Oct. 18, 2021, 4:48 a.m. UTC | #1
On Mon, 2021-10-11 at 04:19 +0000, Soft Works wrote:
> The test /libavutil/tests/hwdevice checks that when deriving a device
> from a source device and then deriving back to the type of the source
> device, the result is matching the original source device, i.e. the
> derivation mechanism doesn't create a new device in this case.
> 
> Previously, this test was usually passed, but only due to two different
> kind of flaws:
> 
> 1. The test covers only a single level of derivation (and back)
> 
> It derives device Y from device X and then Y back to the type of X and
> checks whether the result matches X.
> 
> What it doesn't check for, are longer chains of derivation like:
> 
> CUDA1 > OpenCL2 > CUDA3 and then back to OpenCL4
> 
> In that case, the second derivation returns the first device (CUDA3 ==
> CUDA1), but when deriving OpenCL4, hwcontext.c was creating a new
> OpenCL4 context instead of returning OpenCL2, because there was no link
> from CUDA1 to OpenCL2 (only backwards from OpenCL2 to CUDA1)
> 
> If the test would check for two levels of derivation, it would have
> failed.
> 
> This patch fixes those (yet untested) cases by introducing forward
> references (derived_device) in addition to the existing back references
> (source_device).
> 
> 2. hwcontext_qsv didn't properly set the source_device
> 
> In case of QSV, hwcontext_qsv creates a source context internally
> (vaapi, dxva2 or d3d11va) without calling av_hwdevice_ctx_create_derived
> and without setting source_device.
> 
> This way, the hwcontext test ran successful, but what practically
> happened, was that - for example - deriving vaapi from qsv didn't return
> the original underlying vaapi device and a new one was created instead:
> Exactly what the test is intended to detect and prevent. It just
> couldn't do so, because the original device was hidden (= not set as the
> source_device of the QSV device).
> 
> This patch properly makes these setting and fixes all derivation
> scenarios.
> 
> (at a later stage, /libavutil/tests/hwdevice should be extended to check
> longer derivation chains as well)
> 
> Signed-off-by: softworkz <softworkz@hotmail.com>
> ---
> v3: avoid double-release as suggested by Haihao
> 
>  libavutil/hwcontext.c          | 38 ++++++++++++++++++++++++++++++++++
>  libavutil/hwcontext.h          |  1 +
>  libavutil/hwcontext_internal.h |  6 ++++++
>  libavutil/hwcontext_qsv.c      | 16 ++++++++++----
>  4 files changed, 57 insertions(+), 4 deletions(-)
> 
> diff --git a/libavutil/hwcontext.c b/libavutil/hwcontext.c
> index 31c7840dba..1a50635018 100644
> --- a/libavutil/hwcontext.c
> +++ b/libavutil/hwcontext.c
> @@ -122,6 +122,7 @@ static const AVClass hwdevice_ctx_class = {
>  static void hwdevice_ctx_free(void *opaque, uint8_t *data)
>  {
>      AVHWDeviceContext *ctx = (AVHWDeviceContext*)data;
> +    int i;
>  
>      /* uninit might still want access the hw context and the user
>       * free() callback might destroy it, so uninit has to be called first */
> @@ -132,6 +133,8 @@ static void hwdevice_ctx_free(void *opaque, uint8_t *data)
>          ctx->free(ctx);
>  
>      av_buffer_unref(&ctx->internal->source_device);
> +    for (i = 0; i < AV_HWDEVICE_TYPE_NB; i++)
> +        av_buffer_unref(&ctx->internal->derived_devices[i]);
>  
>      av_freep(&ctx->hwctx);
>      av_freep(&ctx->internal->priv);
> @@ -643,6 +646,26 @@ fail:
>      return ret;
>  }
>  
> +static AVBufferRef* find_derived_hwdevice_ctx(AVBufferRef *src_ref, enum
> AVHWDeviceType type)
> +{
> +    AVBufferRef *tmp_ref;
> +    AVHWDeviceContext *src_ctx;
> +    int i;
> +
> +    src_ctx = (AVHWDeviceContext*)src_ref->data;
> +    if (src_ctx->type == type)
> +        return src_ref;
> +
> +    for (i = 0; i < AV_HWDEVICE_TYPE_NB; i++)
> +        if (src_ctx->internal->derived_devices[i]) {
> +            tmp_ref = find_derived_hwdevice_ctx(src_ctx->internal-
> >derived_devices[i], type);
> +            if (tmp_ref)
> +                return tmp_ref;
> +        }
> +
> +    return NULL;
> +}
> +
>  int av_hwdevice_ctx_create_derived_opts(AVBufferRef **dst_ref_ptr,
>                                          enum AVHWDeviceType type,
>                                          AVBufferRef *src_ref,
> @@ -666,6 +689,16 @@ int av_hwdevice_ctx_create_derived_opts(AVBufferRef
> **dst_ref_ptr,
>          tmp_ref = tmp_ctx->internal->source_device;
>      }
>  
> +    tmp_ref = find_derived_hwdevice_ctx(src_ref, type);
> +    if (tmp_ref) {
> +        dst_ref = av_buffer_ref(tmp_ref);
> +        if (!dst_ref) {
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
> +        goto done;
> +    }
> +
>      dst_ref = av_hwdevice_ctx_alloc(type);
>      if (!dst_ref) {
>          ret = AVERROR(ENOMEM);
> @@ -687,6 +720,11 @@ int av_hwdevice_ctx_create_derived_opts(AVBufferRef
> **dst_ref_ptr,
>                      ret = AVERROR(ENOMEM);
>                      goto fail;
>                  }
> +                tmp_ctx->internal->derived_devices[type] =
> av_buffer_ref(dst_ref);
> +                if (!tmp_ctx->internal->derived_devices[type]) {
> +                    ret = AVERROR(ENOMEM);
> +                    goto fail;
> +                }
>                  ret = av_hwdevice_ctx_init(dst_ref);
>                  if (ret < 0)
>                      goto fail;
> diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
> index 04d19d89c2..56077963e6 100644
> --- a/libavutil/hwcontext.h
> +++ b/libavutil/hwcontext.h
> @@ -37,6 +37,7 @@ enum AVHWDeviceType {
>      AV_HWDEVICE_TYPE_OPENCL,
>      AV_HWDEVICE_TYPE_MEDIACODEC,
>      AV_HWDEVICE_TYPE_VULKAN,
> +    AV_HWDEVICE_TYPE_NB,          ///< number of hw device types
>  };
>  
>  typedef struct AVHWDeviceInternal AVHWDeviceInternal;
> diff --git a/libavutil/hwcontext_internal.h b/libavutil/hwcontext_internal.h
> index e6266494ac..f6fb67c491 100644
> --- a/libavutil/hwcontext_internal.h
> +++ b/libavutil/hwcontext_internal.h
> @@ -109,6 +109,12 @@ struct AVHWDeviceInternal {
>       * context it was derived from.
>       */
>      AVBufferRef *source_device;
> +
> +    /**
> +     * An array of reference to device contexts which
> +     * were derived from this device.
> +     */
> +    AVBufferRef *derived_devices[AV_HWDEVICE_TYPE_NB];
>  };
>  
>  struct AVHWFramesInternal {
> diff --git a/libavutil/hwcontext_qsv.c b/libavutil/hwcontext_qsv.c
> index c18747f7eb..7b559e2b47 100644
> --- a/libavutil/hwcontext_qsv.c
> +++ b/libavutil/hwcontext_qsv.c
> @@ -223,7 +223,7 @@ static void qsv_frames_uninit(AVHWFramesContext *ctx)
>      av_buffer_unref(&s->child_frames_ref);
>  }
>  
> -static void qsv_pool_release_dummy(void *opaque, uint8_t *data)
> +static void qsv_release_dummy(void *opaque, uint8_t *data)
>  {
>  }
>  
> @@ -236,9 +236,9 @@ static AVBufferRef *qsv_pool_alloc(void *opaque, size_t
> size)
>      if (s->nb_surfaces_used < hwctx->nb_surfaces) {
>          s->nb_surfaces_used++;
>          av_buffer_create((uint8_t*)(s->handle_pairs_internal + s-
> >nb_surfaces_used - 1),
> -                                sizeof(*s->handle_pairs_internal),
> qsv_pool_release_dummy, NULL, 0);
> +                                sizeof(*s->handle_pairs_internal),
> qsv_release_dummy, NULL, 0);
>          return av_buffer_create((uint8_t*)(s->surfaces_internal + s-
> >nb_surfaces_used - 1),
> -                                sizeof(*hwctx->surfaces),
> qsv_pool_release_dummy, NULL, 0);
> +                                sizeof(*hwctx->surfaces), qsv_release_dummy,
> NULL, 0);
>      }
>  
>      return NULL;
> @@ -1528,8 +1528,16 @@ static int qsv_device_create(AVHWDeviceContext *ctx,
> const char *device,
>      child_device = (AVHWDeviceContext*)priv->child_device_ctx->data;
>  
>      impl = choose_implementation(device, child_device_type);
> +    ret = qsv_device_derive_from_child(ctx, impl, child_device, 0);
> +    if (ret >= 0) {
> +        ctx->internal->source_device = av_buffer_ref(priv->child_device_ctx);
> +        child_device->internal->derived_devices[ctx->type] =
> av_buffer_create((uint8_t*)ctx, sizeof(*ctx), qsv_release_dummy, ctx, 0);
> +        if (!child_device->internal->derived_devices[ctx->type]) {
> +            return AVERROR(ENOMEM);
> +        }
> +    }
>  
> -    return qsv_device_derive_from_child(ctx, impl, child_device, 0);
> +    return ret;
>  }
>  
>  const HWContextType ff_hwcontext_type_qsv = {

LGTM,

-Haihao
diff mbox series

Patch

diff --git a/libavutil/hwcontext.c b/libavutil/hwcontext.c
index 31c7840dba..1a50635018 100644
--- a/libavutil/hwcontext.c
+++ b/libavutil/hwcontext.c
@@ -122,6 +122,7 @@  static const AVClass hwdevice_ctx_class = {
 static void hwdevice_ctx_free(void *opaque, uint8_t *data)
 {
     AVHWDeviceContext *ctx = (AVHWDeviceContext*)data;
+    int i;
 
     /* uninit might still want access the hw context and the user
      * free() callback might destroy it, so uninit has to be called first */
@@ -132,6 +133,8 @@  static void hwdevice_ctx_free(void *opaque, uint8_t *data)
         ctx->free(ctx);
 
     av_buffer_unref(&ctx->internal->source_device);
+    for (i = 0; i < AV_HWDEVICE_TYPE_NB; i++)
+        av_buffer_unref(&ctx->internal->derived_devices[i]);
 
     av_freep(&ctx->hwctx);
     av_freep(&ctx->internal->priv);
@@ -643,6 +646,26 @@  fail:
     return ret;
 }
 
+static AVBufferRef* find_derived_hwdevice_ctx(AVBufferRef *src_ref, enum AVHWDeviceType type)
+{
+    AVBufferRef *tmp_ref;
+    AVHWDeviceContext *src_ctx;
+    int i;
+
+    src_ctx = (AVHWDeviceContext*)src_ref->data;
+    if (src_ctx->type == type)
+        return src_ref;
+
+    for (i = 0; i < AV_HWDEVICE_TYPE_NB; i++)
+        if (src_ctx->internal->derived_devices[i]) {
+            tmp_ref = find_derived_hwdevice_ctx(src_ctx->internal->derived_devices[i], type);
+            if (tmp_ref)
+                return tmp_ref;
+        }
+
+    return NULL;
+}
+
 int av_hwdevice_ctx_create_derived_opts(AVBufferRef **dst_ref_ptr,
                                         enum AVHWDeviceType type,
                                         AVBufferRef *src_ref,
@@ -666,6 +689,16 @@  int av_hwdevice_ctx_create_derived_opts(AVBufferRef **dst_ref_ptr,
         tmp_ref = tmp_ctx->internal->source_device;
     }
 
+    tmp_ref = find_derived_hwdevice_ctx(src_ref, type);
+    if (tmp_ref) {
+        dst_ref = av_buffer_ref(tmp_ref);
+        if (!dst_ref) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        goto done;
+    }
+
     dst_ref = av_hwdevice_ctx_alloc(type);
     if (!dst_ref) {
         ret = AVERROR(ENOMEM);
@@ -687,6 +720,11 @@  int av_hwdevice_ctx_create_derived_opts(AVBufferRef **dst_ref_ptr,
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
+                tmp_ctx->internal->derived_devices[type] = av_buffer_ref(dst_ref);
+                if (!tmp_ctx->internal->derived_devices[type]) {
+                    ret = AVERROR(ENOMEM);
+                    goto fail;
+                }
                 ret = av_hwdevice_ctx_init(dst_ref);
                 if (ret < 0)
                     goto fail;
diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
index 04d19d89c2..56077963e6 100644
--- a/libavutil/hwcontext.h
+++ b/libavutil/hwcontext.h
@@ -37,6 +37,7 @@  enum AVHWDeviceType {
     AV_HWDEVICE_TYPE_OPENCL,
     AV_HWDEVICE_TYPE_MEDIACODEC,
     AV_HWDEVICE_TYPE_VULKAN,
+    AV_HWDEVICE_TYPE_NB,          ///< number of hw device types
 };
 
 typedef struct AVHWDeviceInternal AVHWDeviceInternal;
diff --git a/libavutil/hwcontext_internal.h b/libavutil/hwcontext_internal.h
index e6266494ac..f6fb67c491 100644
--- a/libavutil/hwcontext_internal.h
+++ b/libavutil/hwcontext_internal.h
@@ -109,6 +109,12 @@  struct AVHWDeviceInternal {
      * context it was derived from.
      */
     AVBufferRef *source_device;
+
+    /**
+     * An array of reference to device contexts which
+     * were derived from this device.
+     */
+    AVBufferRef *derived_devices[AV_HWDEVICE_TYPE_NB];
 };
 
 struct AVHWFramesInternal {
diff --git a/libavutil/hwcontext_qsv.c b/libavutil/hwcontext_qsv.c
index c18747f7eb..7b559e2b47 100644
--- a/libavutil/hwcontext_qsv.c
+++ b/libavutil/hwcontext_qsv.c
@@ -223,7 +223,7 @@  static void qsv_frames_uninit(AVHWFramesContext *ctx)
     av_buffer_unref(&s->child_frames_ref);
 }
 
-static void qsv_pool_release_dummy(void *opaque, uint8_t *data)
+static void qsv_release_dummy(void *opaque, uint8_t *data)
 {
 }
 
@@ -236,9 +236,9 @@  static AVBufferRef *qsv_pool_alloc(void *opaque, size_t size)
     if (s->nb_surfaces_used < hwctx->nb_surfaces) {
         s->nb_surfaces_used++;
         av_buffer_create((uint8_t*)(s->handle_pairs_internal + s->nb_surfaces_used - 1),
-                                sizeof(*s->handle_pairs_internal), qsv_pool_release_dummy, NULL, 0);
+                                sizeof(*s->handle_pairs_internal), qsv_release_dummy, NULL, 0);
         return av_buffer_create((uint8_t*)(s->surfaces_internal + s->nb_surfaces_used - 1),
-                                sizeof(*hwctx->surfaces), qsv_pool_release_dummy, NULL, 0);
+                                sizeof(*hwctx->surfaces), qsv_release_dummy, NULL, 0);
     }
 
     return NULL;
@@ -1528,8 +1528,16 @@  static int qsv_device_create(AVHWDeviceContext *ctx, const char *device,
     child_device = (AVHWDeviceContext*)priv->child_device_ctx->data;
 
     impl = choose_implementation(device, child_device_type);
+    ret = qsv_device_derive_from_child(ctx, impl, child_device, 0);
+    if (ret >= 0) {
+        ctx->internal->source_device = av_buffer_ref(priv->child_device_ctx);
+        child_device->internal->derived_devices[ctx->type] = av_buffer_create((uint8_t*)ctx, sizeof(*ctx), qsv_release_dummy, ctx, 0);
+        if (!child_device->internal->derived_devices[ctx->type]) {
+            return AVERROR(ENOMEM);
+        }
+    }
 
-    return qsv_device_derive_from_child(ctx, impl, child_device, 0);
+    return ret;
 }
 
 const HWContextType ff_hwcontext_type_qsv = {