[PATCHv3,05/11] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
Commit Message
This patch lets user-space to request a non-consistent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.
= CREATE_BUFS
struct v4l2_create_buffers has seven 4-byte reserved areas,
so reserved[0] is renamed to ->flags. The struct, thus, now
has six reserved 4-byte regions.
= REQBUFS
We use one bit of a ->reserved[1] member of struct v4l2_requestbuffers,
which is now renamed to ->flags. Unlike v4l2_create_buffers, struct
v4l2_requestbuffers does not have enough reserved room. Therefore for
backward compatibility ->reserved and ->flags were put into anonymous
union.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
.../media/uapi/v4l/vidioc-create-bufs.rst | 8 ++++-
.../media/uapi/v4l/vidioc-reqbufs.rst | 15 +++++++--
.../media/common/videobuf2/videobuf2-v4l2.c | 31 +++++++++++++++++--
drivers/media/v4l2-core/v4l2-ioctl.c | 5 +--
include/uapi/linux/videodev2.h | 8 +++--
5 files changed, 54 insertions(+), 13 deletions(-)
Comments
On 2/26/20 12:15 PM, Sergey Senozhatsky wrote:
> This patch lets user-space to request a non-consistent memory
> allocation during CREATE_BUFS and REQBUFS ioctl calls.
>
> = CREATE_BUFS
>
> struct v4l2_create_buffers has seven 4-byte reserved areas,
> so reserved[0] is renamed to ->flags. The struct, thus, now
> has six reserved 4-byte regions.
>
> = REQBUFS
>
> We use one bit of a ->reserved[1] member of struct v4l2_requestbuffers,
> which is now renamed to ->flags. Unlike v4l2_create_buffers, struct
> v4l2_requestbuffers does not have enough reserved room. Therefore for
> backward compatibility ->reserved and ->flags were put into anonymous
> union.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
> .../media/uapi/v4l/vidioc-create-bufs.rst | 8 ++++-
> .../media/uapi/v4l/vidioc-reqbufs.rst | 15 +++++++--
> .../media/common/videobuf2/videobuf2-v4l2.c | 31 +++++++++++++++++--
> drivers/media/v4l2-core/v4l2-ioctl.c | 5 +--
> include/uapi/linux/videodev2.h | 8 +++--
> 5 files changed, 54 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> index bd08e4f77ae4..6a8a4d5de2f1 100644
> --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> @@ -121,7 +121,13 @@ than the number requested.
> other changes, then set ``count`` to 0, ``memory`` to
> ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
> * - __u32
> - - ``reserved``\ [7]
> + - ``flags``
> + - Specifies additional buffer management attributes.
> + See :ref:`memory-flags`. Old drivers and applications must set it to
> + zero.
Drop the last sentence, it's not relevant.
> +
> + * - __u32
> + - ``reserved``\ [6]
> - A place holder for future extensions. Drivers and applications
> must set the array to zero.
Old drivers and applications still think reserved is [7] and will zero this.
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> index 917df6fb6486..e52cc4401fba 100644
> --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> @@ -112,10 +112,19 @@ aborting or finishing any DMA in progress, an implicit
> ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
> free any previously allocated buffers, so this is typically something
> that will be done at the start of the application.
> - * - __u32
> + * - union
> + - (anonymous)
Anonymous unions are formatted a bit differently (I made a very recent patch
that unified the union formatting in the v4l docs). See e.g.
Documentation/media/uapi/v4l/vidioc-g-ext-ctrls.rst.
> + * -
> + - __u32
> + - ``flags``\ [1]
> + - Specifies additional buffer management attributes.
> + See :ref:`memory-flags`. Old drivers and applications must set it to
> + zero.
Ditto.
> +
> + * -
> + - __u32
> - ``reserved``\ [1]
> - - A place holder for future extensions. Drivers and applications
> - must set the array to zero.
> + - Kept for backwards compatibility. Use ``flags`` instead.
>
> .. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}|
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index cc31629c06dc..4954c9fc678d 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -722,9 +722,18 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
> int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
> {
> int ret = vb2_verify_memory_type(q, req->memory, req->type);
> + bool consistent = true;
> +
> + if (!vb2_queue_allows_cache_hints(q))
> + req->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
> +
> + if (req->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> + consistent = false;
>
> fill_buf_caps(q, &req->capabilities);
> - return ret ? ret : vb2_core_reqbufs(q, req->memory, true, &req->count);
> + if (ret)
> + return ret;
> + return vb2_core_reqbufs(q, req->memory, consistent, &req->count);
> }
> EXPORT_SYMBOL_GPL(vb2_reqbufs);
>
> @@ -753,6 +762,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> unsigned requested_sizes[VIDEO_MAX_PLANES];
> struct v4l2_format *f = &create->format;
> int ret = vb2_verify_memory_type(q, create->memory, f->type);
> + bool consistent = true;
> unsigned i;
>
> fill_buf_caps(q, &create->capabilities);
> @@ -798,7 +808,14 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> for (i = 0; i < requested_planes; i++)
> if (requested_sizes[i] == 0)
> return -EINVAL;
> - return ret ? ret : vb2_core_create_bufs(q, create->memory, true,
> +
> + if (!vb2_queue_allows_cache_hints(q))
> + create->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
> +
> + if (create->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> + consistent = false;
> +
> + return ret ? ret : vb2_core_create_bufs(q, create->memory, consistent,
> &create->count, requested_planes, requested_sizes);
> }
> EXPORT_SYMBOL_GPL(vb2_create_bufs);
> @@ -968,13 +985,21 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
> {
> struct video_device *vdev = video_devdata(file);
> int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
> + bool consistent = true;
>
> fill_buf_caps(vdev->queue, &p->capabilities);
> if (res)
> return res;
> if (vb2_queue_is_busy(vdev, file))
> return -EBUSY;
> - res = vb2_core_reqbufs(vdev->queue, p->memory, true, &p->count);
> +
> + if (!vb2_queue_allows_cache_hints(vdev->queue))
> + p->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
> +
> + if (p->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> + consistent = false;
> +
> + res = vb2_core_reqbufs(vdev->queue, p->memory, consistent, &p->count);
> /* If count == 0, then the owner has released all buffers and he
> is no longer owner of the queue. Otherwise we have a new owner. */
> if (res == 0)
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index fbcc7a20eedf..53b87bfd50d7 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1973,9 +1973,6 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
>
> if (ret)
> return ret;
> -
> - CLEAR_AFTER_FIELD(p, capabilities);
> -
> return ops->vidioc_reqbufs(file, fh, p);
> }
>
> @@ -2015,7 +2012,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
> if (ret)
> return ret;
>
> - CLEAR_AFTER_FIELD(create, capabilities);
> + CLEAR_AFTER_FIELD(create, flags);
>
> v4l_sanitize_format(&create->format);
>
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index e92c29864730..12b1bd220347 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -938,7 +938,10 @@ struct v4l2_requestbuffers {
> __u32 type; /* enum v4l2_buf_type */
> __u32 memory; /* enum v4l2_memory */
> __u32 capabilities;
> - __u32 reserved[1];
> + union {
> + __u32 flags;
> + __u32 reserved[1];
> + };
> };
>
> /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
> @@ -2446,7 +2449,8 @@ struct v4l2_create_buffers {
> __u32 memory;
> struct v4l2_format format;
> __u32 capabilities;
> - __u32 reserved[7];
> + __u32 flags;
> + __u32 reserved[6];
> };
>
> /*
>
Regards,
Hans
On (20/02/27 13:36), Hans Verkuil wrote:
> > diff --git a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> > index bd08e4f77ae4..6a8a4d5de2f1 100644
> > --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> > +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> > @@ -121,7 +121,13 @@ than the number requested.
> > other changes, then set ``count`` to 0, ``memory`` to
> > ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
> > * - __u32
> > - - ``reserved``\ [7]
> > + - ``flags``
> > + - Specifies additional buffer management attributes.
> > + See :ref:`memory-flags`. Old drivers and applications must set it to
> > + zero.
>
> Drop the last sentence, it's not relevant.
OK.
> > +
> > + * - __u32
> > + - ``reserved``\ [6]
> > - A place holder for future extensions. Drivers and applications
> > must set the array to zero.
>
> Old drivers and applications still think reserved is [7] and will zero this.
OK.
Hmm... If those apps use hard-coded size then we might have a problem.
If they use sizeof(reserved) then everything is OK. Shall we also have
a union here?
> > diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > index 917df6fb6486..e52cc4401fba 100644
> > --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > @@ -112,10 +112,19 @@ aborting or finishing any DMA in progress, an implicit
> > ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
> > free any previously allocated buffers, so this is typically something
> > that will be done at the start of the application.
> > - * - __u32
> > + * - union
> > + - (anonymous)
>
> Anonymous unions are formatted a bit differently (I made a very recent patch
> that unified the union formatting in the v4l docs). See e.g.
> Documentation/media/uapi/v4l/vidioc-g-ext-ctrls.rst.
OK, will take a look.
-ss
On (20/02/27 13:36), Hans Verkuil wrote:
[..]
> > other changes, then set ``count`` to 0, ``memory`` to
> > ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
> > * - __u32
> > - - ``reserved``\ [7]
> > + - ``flags``
> > + - Specifies additional buffer management attributes.
> > + See :ref:`memory-flags`. Old drivers and applications must set it to
> > + zero.
>
> Drop the last sentence, it's not relevant.
>
> > +
> > + * - __u32
> > + - ``reserved``\ [6]
> > - A place holder for future extensions. Drivers and applications
> > must set the array to zero.
>
> Old drivers and applications still think reserved is [7] and will zero this.
Just to make sure, does this mean that you also want me to drop the
"Drivers and applications must set the array to zero" sentence?
-ss
On 2/28/20 2:38 AM, Sergey Senozhatsky wrote:
> On (20/02/27 13:36), Hans Verkuil wrote:
>>> diff --git a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
>>> index bd08e4f77ae4..6a8a4d5de2f1 100644
>>> --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
>>> +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
>>> @@ -121,7 +121,13 @@ than the number requested.
>>> other changes, then set ``count`` to 0, ``memory`` to
>>> ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
>>> * - __u32
>>> - - ``reserved``\ [7]
>>> + - ``flags``
>>> + - Specifies additional buffer management attributes.
>>> + See :ref:`memory-flags`. Old drivers and applications must set it to
>>> + zero.
>>
>> Drop the last sentence, it's not relevant.
>
> OK.
>
>>> +
>>> + * - __u32
>>> + - ``reserved``\ [6]
>>> - A place holder for future extensions. Drivers and applications
>>> must set the array to zero.
>>
>> Old drivers and applications still think reserved is [7] and will zero this.
>
> OK.
>
> Hmm... If those apps use hard-coded size then we might have a problem.
> If they use sizeof(reserved) then everything is OK. Shall we also have
> a union here?
No, apps will use sizeof(reserved).
Regards,
Hans
>
>>> diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
>>> index 917df6fb6486..e52cc4401fba 100644
>>> --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
>>> +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
>>> @@ -112,10 +112,19 @@ aborting or finishing any DMA in progress, an implicit
>>> ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
>>> free any previously allocated buffers, so this is typically something
>>> that will be done at the start of the application.
>>> - * - __u32
>>> + * - union
>>> + - (anonymous)
>>
>> Anonymous unions are formatted a bit differently (I made a very recent patch
>> that unified the union formatting in the v4l docs). See e.g.
>> Documentation/media/uapi/v4l/vidioc-g-ext-ctrls.rst.
>
> OK, will take a look.
>
> -ss
>
On 2/28/20 4:57 AM, Sergey Senozhatsky wrote:
> On (20/02/27 13:36), Hans Verkuil wrote:
> [..]
>>> other changes, then set ``count`` to 0, ``memory`` to
>>> ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
>>> * - __u32
>>> - - ``reserved``\ [7]
>>> + - ``flags``
>>> + - Specifies additional buffer management attributes.
>>> + See :ref:`memory-flags`. Old drivers and applications must set it to
>>> + zero.
>>
>> Drop the last sentence, it's not relevant.
>>
>>> +
>>> + * - __u32
>>> + - ``reserved``\ [6]
>>> - A place holder for future extensions. Drivers and applications
>>> must set the array to zero.
>>
>> Old drivers and applications still think reserved is [7] and will zero this.
>
> Just to make sure, does this mean that you also want me to drop the
> "Drivers and applications must set the array to zero" sentence?
Not for the reserved field, only for the flags field.
Regards,
Hans
>
> -ss
>
On (20/02/28 09:50), Hans Verkuil wrote:
> On 2/28/20 4:57 AM, Sergey Senozhatsky wrote:
> > On (20/02/27 13:36), Hans Verkuil wrote:
> > [..]
[..]
> >>> + * - __u32
> >>> + - ``reserved``\ [6]
> >>> - A place holder for future extensions. Drivers and applications
> >>> must set the array to zero.
> >>
> >> Old drivers and applications still think reserved is [7] and will zero this.
> >
> > Just to make sure, does this mean that you also want me to drop the
> > "Drivers and applications must set the array to zero" sentence?
>
> Not for the reserved field, only for the flags field.
Got it.
So V4 is ready. Do you think it'll make sense to send it
out now or next week?
-ss
@@ -121,7 +121,13 @@ than the number requested.
other changes, then set ``count`` to 0, ``memory`` to
``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
* - __u32
- - ``reserved``\ [7]
+ - ``flags``
+ - Specifies additional buffer management attributes.
+ See :ref:`memory-flags`. Old drivers and applications must set it to
+ zero.
+
+ * - __u32
+ - ``reserved``\ [6]
- A place holder for future extensions. Drivers and applications
must set the array to zero.
@@ -112,10 +112,19 @@ aborting or finishing any DMA in progress, an implicit
``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
free any previously allocated buffers, so this is typically something
that will be done at the start of the application.
- * - __u32
+ * - union
+ - (anonymous)
+ * -
+ - __u32
+ - ``flags``\ [1]
+ - Specifies additional buffer management attributes.
+ See :ref:`memory-flags`. Old drivers and applications must set it to
+ zero.
+
+ * -
+ - __u32
- ``reserved``\ [1]
- - A place holder for future extensions. Drivers and applications
- must set the array to zero.
+ - Kept for backwards compatibility. Use ``flags`` instead.
.. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}|
@@ -722,9 +722,18 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
{
int ret = vb2_verify_memory_type(q, req->memory, req->type);
+ bool consistent = true;
+
+ if (!vb2_queue_allows_cache_hints(q))
+ req->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
+
+ if (req->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
+ consistent = false;
fill_buf_caps(q, &req->capabilities);
- return ret ? ret : vb2_core_reqbufs(q, req->memory, true, &req->count);
+ if (ret)
+ return ret;
+ return vb2_core_reqbufs(q, req->memory, consistent, &req->count);
}
EXPORT_SYMBOL_GPL(vb2_reqbufs);
@@ -753,6 +762,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
unsigned requested_sizes[VIDEO_MAX_PLANES];
struct v4l2_format *f = &create->format;
int ret = vb2_verify_memory_type(q, create->memory, f->type);
+ bool consistent = true;
unsigned i;
fill_buf_caps(q, &create->capabilities);
@@ -798,7 +808,14 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
for (i = 0; i < requested_planes; i++)
if (requested_sizes[i] == 0)
return -EINVAL;
- return ret ? ret : vb2_core_create_bufs(q, create->memory, true,
+
+ if (!vb2_queue_allows_cache_hints(q))
+ create->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
+
+ if (create->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
+ consistent = false;
+
+ return ret ? ret : vb2_core_create_bufs(q, create->memory, consistent,
&create->count, requested_planes, requested_sizes);
}
EXPORT_SYMBOL_GPL(vb2_create_bufs);
@@ -968,13 +985,21 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
{
struct video_device *vdev = video_devdata(file);
int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
+ bool consistent = true;
fill_buf_caps(vdev->queue, &p->capabilities);
if (res)
return res;
if (vb2_queue_is_busy(vdev, file))
return -EBUSY;
- res = vb2_core_reqbufs(vdev->queue, p->memory, true, &p->count);
+
+ if (!vb2_queue_allows_cache_hints(vdev->queue))
+ p->flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
+
+ if (p->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
+ consistent = false;
+
+ res = vb2_core_reqbufs(vdev->queue, p->memory, consistent, &p->count);
/* If count == 0, then the owner has released all buffers and he
is no longer owner of the queue. Otherwise we have a new owner. */
if (res == 0)
@@ -1973,9 +1973,6 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
if (ret)
return ret;
-
- CLEAR_AFTER_FIELD(p, capabilities);
-
return ops->vidioc_reqbufs(file, fh, p);
}
@@ -2015,7 +2012,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
if (ret)
return ret;
- CLEAR_AFTER_FIELD(create, capabilities);
+ CLEAR_AFTER_FIELD(create, flags);
v4l_sanitize_format(&create->format);
@@ -938,7 +938,10 @@ struct v4l2_requestbuffers {
__u32 type; /* enum v4l2_buf_type */
__u32 memory; /* enum v4l2_memory */
__u32 capabilities;
- __u32 reserved[1];
+ union {
+ __u32 flags;
+ __u32 reserved[1];
+ };
};
/* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
@@ -2446,7 +2449,8 @@ struct v4l2_create_buffers {
__u32 memory;
struct v4l2_format format;
__u32 capabilities;
- __u32 reserved[7];
+ __u32 flags;
+ __u32 reserved[6];
};
/*