Re: media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin

Re: media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin

[Guillaume Tucker]

Please see the bisection report below about a regression in
v4l2-compliance with uvcvideo:

[   25.495039] uvcvideo: Failed to query (SET_CUR) UVC control 10 on unit 2: -32 (exp. 2).
		fail: v4l2-test-buffers.cpp(680): check_0(reqbufs.reserved, sizeof(reqbufs.reserved))
	test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: FAIL


as seen in the full job log:

    https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html#L1713

with a few more details about the regression here:

    https://kernelci.org/test/case/id/5ef23169140826f73d97bf51/

and the same test case failure also seen with vivid:

    https://kernelci.org/test/case/id/5ef23699f641f7b3e597bf3f/


The bisection actually ran a couple of days ago but there was an
email error when sending the report, so I'm sending it by hand
now.  I hope the issue hasn't spread too widely already, I know
it's also affecting linux-next.

Guillaume


On 25/06/2020 23:19, kernelci.org bot wrote:
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> * This automated bisection report was sent to you on the basis  *
> * that you may be involved with the breaking commit it has      *
> * found.  No manual investigation has been done to verify it,   *
> * and the root cause of the problem may be somewhere else.      *
> *                                                               *
> * If you do send a fix, please include this trailer:            *
> *   Reported-by: "kernelci.org bot" <bot@kernelci.org>          *
> *                                                               *
> * Hope this helps!                                              *
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> 
> media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin
> 
> Summary:
>   Start:      e30cc79cc80f media: media-request: Fix crash if memory allocation fails
>   Plain log:  https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.txt
>   HTML log:   https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html
>   Result:     1e0b2318fa75 media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
> 
> Checks:
>   revert:     PASS
>   verify:     PASS
> 
> Parameters:
>   Tree:       media
>   URL:        https://git.linuxtv.org/media_tree.git
>   Branch:     master
>   Target:     rk3399-gru-kevin
>   CPU arch:   arm64
>   Lab:        lab-collabora
>   Compiler:   gcc-8
>   Config:     defconfig
>   Test case:  v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF
> 
> Breaking commit found:
> 
> -------------------------------------------------------------------------------
> commit 1e0b2318fa75d186ee0d2be31843ce867385fcc4
> Author: Sergey Senozhatsky <senozhatsky@chromium.org>
> Date:   Thu May 14 18:01:45 2020 +0200
> 
>     media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>     
>     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.
>     
>     = CREATE_BUFS32
>     
>       struct v4l2_create_buffers32 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>
>     Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>     Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> 
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
> index e1afc5b504c2..f2a702870fad 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
> @@ -121,7 +121,12 @@ 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`.
> +
> +    * - __u32
> +      - ``reserved``\ [6]
>        - A place holder for future extensions. Drivers and applications
>  	must set the array to zero.
>  
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
> index 96a59793d857..75d894d9c36c 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
> @@ -112,10 +112,17 @@ 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.
> +    * - union {
> +      - (anonymous)
> +    * - __u32
> +      - ``flags``
> +      - Specifies additional buffer management attributes.
> +	See :ref:`memory-flags`.
>      * - __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-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 0fdcf90330df..626c4db5134c 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -694,6 +694,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
>  	unsigned int i;
>  	int ret;
>  
> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> +		consistent_mem = false;
> +
>  	if (q->streaming) {
>  		dprintk(1, "streaming active\n");
>  		return -EBUSY;
> @@ -837,6 +840,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
>  	bool consistent_mem = true;
>  	int ret;
>  
> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> +		consistent_mem = false;
> +
>  	if (q->num_buffers == VB2_MAX_FRAME) {
>  		dprintk(1, "maximum number of buffers already allocated\n");
>  		return -ENOBUFS;
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 26a3ec333bb7..559a229cac41 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -718,12 +718,22 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
>  #endif
>  }
>  
> +static void clear_consistency_attr(struct vb2_queue *q,
> +				   int memory,
> +				   unsigned int *flags)
> +{
> +	if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP)
> +		*flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
> +}
> +
>  int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
>  {
>  	int ret = vb2_verify_memory_type(q, req->memory, req->type);
>  
>  	fill_buf_caps(q, &req->capabilities);
> -	return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
> +	clear_consistency_attr(q, req->memory, &req->flags);
> +	return ret ? ret : vb2_core_reqbufs(q, req->memory,
> +					    req->flags, &req->count);
>  }
>  EXPORT_SYMBOL_GPL(vb2_reqbufs);
>  
> @@ -755,6 +765,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>  	unsigned i;
>  
>  	fill_buf_caps(q, &create->capabilities);
> +	clear_consistency_attr(q, create->memory, &create->flags);
>  	create->index = q->num_buffers;
>  	if (create->count == 0)
>  		return ret != -EBUSY ? ret : 0;
> @@ -797,8 +808,11 @@ 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, 0,
> -		&create->count, requested_planes, requested_sizes);
> +	return ret ? ret : vb2_core_create_bufs(q, create->memory,
> +						create->flags,
> +						&create->count,
> +						requested_planes,
> +						requested_sizes);
>  }
>  EXPORT_SYMBOL_GPL(vb2_create_bufs);
>  
> @@ -969,11 +983,12 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
>  	int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
>  
>  	fill_buf_caps(vdev->queue, &p->capabilities);
> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>  	if (res)
>  		return res;
>  	if (vb2_queue_is_busy(vdev, file))
>  		return -EBUSY;
> -	res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
> +	res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &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)
> @@ -991,6 +1006,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
>  
>  	p->index = vdev->queue->num_buffers;
>  	fill_buf_caps(vdev->queue, &p->capabilities);
> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>  	/*
>  	 * If count == 0, then just check if memory and type are valid.
>  	 * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> index a99e82ec9ab6..593bcf6c3735 100644
> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> @@ -246,6 +246,9 @@ struct v4l2_format32 {
>   * @memory:	buffer memory type
>   * @format:	frame format, for which buffers are requested
>   * @capabilities: capabilities of this buffer type.
> + * @flags:	additional buffer management attributes (ignored unless the
> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
> + *		configured for MMAP streaming I/O).
>   * @reserved:	future extensions
>   */
>  struct v4l2_create_buffers32 {
> @@ -254,7 +257,8 @@ struct v4l2_create_buffers32 {
>  	__u32			memory;	/* enum v4l2_memory */
>  	struct v4l2_format32	format;
>  	__u32			capabilities;
> -	__u32			reserved[7];
> +	__u32			flags;
> +	__u32			reserved[6];
>  };
>  
>  static int __bufsize_v4l2_format(struct v4l2_format32 __user *p32, u32 *size)
> @@ -355,7 +359,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers __user *p64,
>  {
>  	if (!access_ok(p32, sizeof(*p32)) ||
>  	    copy_in_user(p64, p32,
> -			 offsetof(struct v4l2_create_buffers32, format)))
> +			 offsetof(struct v4l2_create_buffers32, format)) ||
> +	    assign_in_user(&p64->flags, &p32->flags))
>  		return -EFAULT;
>  	return __get_v4l2_format32(&p64->format, &p32->format,
>  				   aux_buf, aux_space);
> @@ -417,6 +422,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers __user *p64,
>  	    copy_in_user(p32, p64,
>  			 offsetof(struct v4l2_create_buffers32, format)) ||
>  	    assign_in_user(&p32->capabilities, &p64->capabilities) ||
> +	    assign_in_user(&p32->flags, &p64->flags) ||
>  	    copy_in_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
>  		return -EFAULT;
>  	return __put_v4l2_format32(&p64->format, &p32->format);
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 2322f08a98be..02bfef0da76d 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -2038,9 +2038,6 @@ 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);
>  }
>  
> @@ -2080,7 +2077,7 @@ 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 34ba1017b89b..fec2607a07e3 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -946,7 +946,10 @@ 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 */
> @@ -2450,6 +2453,9 @@ struct v4l2_dbg_chip_info {
>   * @memory:	enum v4l2_memory; buffer memory type
>   * @format:	frame format, for which buffers are requested
>   * @capabilities: capabilities of this buffer type.
> + * @flags:	additional buffer management attributes (ignored unless the
> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
> + *		and configured for MMAP streaming I/O).
>   * @reserved:	future extensions
>   */
>  struct v4l2_create_buffers {
> @@ -2458,7 +2464,8 @@ struct v4l2_create_buffers {
>  	__u32			memory;
>  	struct v4l2_format	format;
>  	__u32			capabilities;
> -	__u32			reserved[7];
> +	__u32			flags;
> +	__u32			reserved[6];
>  };
>  
>  /*
> -------------------------------------------------------------------------------
> 
> 
> Git bisection log:
> 
> -------------------------------------------------------------------------------
> git bisect start
> # good: [2630e1bb0948c3134c6f22ad275ae27cc6023532] media: rkvdec: Fix H264 scaling list order
> git bisect good 2630e1bb0948c3134c6f22ad275ae27cc6023532
> # bad: [e30cc79cc80fd919b697a15c5000d9f57487de8e] media: media-request: Fix crash if memory allocation fails
> git bisect bad e30cc79cc80fd919b697a15c5000d9f57487de8e
> # good: [cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
> git bisect good cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2
> # good: [3b69e8b4571125bec1f77f886174fe6cab6b9d75] Merge tag 'sh-for-5.8' of git://git.libc.org/linux-sh
> git bisect good 3b69e8b4571125bec1f77f886174fe6cab6b9d75
> # good: [3ed740841bf94a8028ec44164d84f9af9bd552fd] maccess: remove duplicate kerneldoc comments
> git bisect good 3ed740841bf94a8028ec44164d84f9af9bd552fd
> # good: [2ab70319bc1f79228da4dce7b9d604740c9beeef] nmi, tracing: Make hardware latency tracing noinstr safe
> git bisect good 2ab70319bc1f79228da4dce7b9d604740c9beeef
> # good: [df2fbf5bfa0e7fff8b4784507e4d68f200454318] Merge tag 'thermal-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux
> git bisect good df2fbf5bfa0e7fff8b4784507e4d68f200454318
> # good: [91fa58840ae22cbf6d7c505ce6564c4c48f29af3] Merge branch 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
> git bisect good 91fa58840ae22cbf6d7c505ce6564c4c48f29af3
> # good: [bc139119a1708ae3db1ebb379630f286e28d06e8] net: ethernet: ti: ale: fix allmulti for nu type ale
> git bisect good bc139119a1708ae3db1ebb379630f286e28d06e8
> # good: [157282a5c6273976b31cf4ba4b1c46663f6519d1] media: s5k6a3: Fix runtime PM imbalance on error
> git bisect good 157282a5c6273976b31cf4ba4b1c46663f6519d1
> # bad: [286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc] media: videodev2.h: add V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL flag
> git bisect bad 286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc
> # good: [ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e] media: videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag
> git bisect good ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e
> # bad: [d4db5eb57cab049d378fbfb7ee842857009a8679] media: videobuf2: add begin/end cpu_access callbacks to dma-sg
> git bisect bad d4db5eb57cab049d378fbfb7ee842857009a8679
> # bad: [38a417e88aad1e5ad5ff2647d4cd26040b567fc3] media: videobuf2: factor out planes prepare/finish functions
> git bisect bad 38a417e88aad1e5ad5ff2647d4cd26040b567fc3
> # bad: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
> git bisect bad 1e0b2318fa75d186ee0d2be31843ce867385fcc4
> # good: [7b4b45555c79db03dad8192e6ef85cb30236827b] media: videobuf2: add queue memory consistency parameter
> git bisect good 7b4b45555c79db03dad8192e6ef85cb30236827b
> # first bad commit: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
> -------------------------------------------------------------------------------
> 

Re: media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin

[Hans Verkuil]

Hi Guillaume,

You need to update v4l-utils to the latest version from our git master branch.

The reserved field in reqbufs is now in use as a flags field, so it is no longer
zero. The compliance test has been updated accordingly in the v4l-utils git repo.

Regards,

	Hans

On 26/06/2020 08:56, Guillaume Tucker wrote:
> Please see the bisection report below about a regression in
> v4l2-compliance with uvcvideo:
> 
> [   25.495039] uvcvideo: Failed to query (SET_CUR) UVC control 10 on unit 2: -32 (exp. 2).
> 		fail: v4l2-test-buffers.cpp(680): check_0(reqbufs.reserved, sizeof(reqbufs.reserved))
> 	test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: FAIL
> 
> 
> as seen in the full job log:
> 
>     https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html#L1713
> 
> with a few more details about the regression here:
> 
>     https://kernelci.org/test/case/id/5ef23169140826f73d97bf51/
> 
> and the same test case failure also seen with vivid:
> 
>     https://kernelci.org/test/case/id/5ef23699f641f7b3e597bf3f/
> 
> 
> The bisection actually ran a couple of days ago but there was an
> email error when sending the report, so I'm sending it by hand
> now.  I hope the issue hasn't spread too widely already, I know
> it's also affecting linux-next.
> 
> Guillaume
> 
> 
> On 25/06/2020 23:19, kernelci.org bot wrote:
>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>> * This automated bisection report was sent to you on the basis  *
>> * that you may be involved with the breaking commit it has      *
>> * found.  No manual investigation has been done to verify it,   *
>> * and the root cause of the problem may be somewhere else.      *
>> *                                                               *
>> * If you do send a fix, please include this trailer:            *
>> *   Reported-by: "kernelci.org bot" <bot@kernelci.org>          *
>> *                                                               *
>> * Hope this helps!                                              *
>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>>
>> media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin
>>
>> Summary:
>>   Start:      e30cc79cc80f media: media-request: Fix crash if memory allocation fails
>>   Plain log:  https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.txt
>>   HTML log:   https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html
>>   Result:     1e0b2318fa75 media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>
>> Checks:
>>   revert:     PASS
>>   verify:     PASS
>>
>> Parameters:
>>   Tree:       media
>>   URL:        https://git.linuxtv.org/media_tree.git
>>   Branch:     master
>>   Target:     rk3399-gru-kevin
>>   CPU arch:   arm64
>>   Lab:        lab-collabora
>>   Compiler:   gcc-8
>>   Config:     defconfig
>>   Test case:  v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF
>>
>> Breaking commit found:
>>
>> -------------------------------------------------------------------------------
>> commit 1e0b2318fa75d186ee0d2be31843ce867385fcc4
>> Author: Sergey Senozhatsky <senozhatsky@chromium.org>
>> Date:   Thu May 14 18:01:45 2020 +0200
>>
>>     media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>     
>>     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.
>>     
>>     = CREATE_BUFS32
>>     
>>       struct v4l2_create_buffers32 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>
>>     Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>>     Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
>>
>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>> index e1afc5b504c2..f2a702870fad 100644
>> --- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>> +++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>> @@ -121,7 +121,12 @@ 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`.
>> +
>> +    * - __u32
>> +      - ``reserved``\ [6]
>>        - A place holder for future extensions. Drivers and applications
>>  	must set the array to zero.
>>  
>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>> index 96a59793d857..75d894d9c36c 100644
>> --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>> +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>> @@ -112,10 +112,17 @@ 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.
>> +    * - union {
>> +      - (anonymous)
>> +    * - __u32
>> +      - ``flags``
>> +      - Specifies additional buffer management attributes.
>> +	See :ref:`memory-flags`.
>>      * - __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-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>> index 0fdcf90330df..626c4db5134c 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>> @@ -694,6 +694,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
>>  	unsigned int i;
>>  	int ret;
>>  
>> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
>> +		consistent_mem = false;
>> +
>>  	if (q->streaming) {
>>  		dprintk(1, "streaming active\n");
>>  		return -EBUSY;
>> @@ -837,6 +840,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
>>  	bool consistent_mem = true;
>>  	int ret;
>>  
>> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
>> +		consistent_mem = false;
>> +
>>  	if (q->num_buffers == VB2_MAX_FRAME) {
>>  		dprintk(1, "maximum number of buffers already allocated\n");
>>  		return -ENOBUFS;
>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> index 26a3ec333bb7..559a229cac41 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> @@ -718,12 +718,22 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
>>  #endif
>>  }
>>  
>> +static void clear_consistency_attr(struct vb2_queue *q,
>> +				   int memory,
>> +				   unsigned int *flags)
>> +{
>> +	if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP)
>> +		*flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
>> +}
>> +
>>  int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
>>  {
>>  	int ret = vb2_verify_memory_type(q, req->memory, req->type);
>>  
>>  	fill_buf_caps(q, &req->capabilities);
>> -	return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
>> +	clear_consistency_attr(q, req->memory, &req->flags);
>> +	return ret ? ret : vb2_core_reqbufs(q, req->memory,
>> +					    req->flags, &req->count);
>>  }
>>  EXPORT_SYMBOL_GPL(vb2_reqbufs);
>>  
>> @@ -755,6 +765,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>>  	unsigned i;
>>  
>>  	fill_buf_caps(q, &create->capabilities);
>> +	clear_consistency_attr(q, create->memory, &create->flags);
>>  	create->index = q->num_buffers;
>>  	if (create->count == 0)
>>  		return ret != -EBUSY ? ret : 0;
>> @@ -797,8 +808,11 @@ 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, 0,
>> -		&create->count, requested_planes, requested_sizes);
>> +	return ret ? ret : vb2_core_create_bufs(q, create->memory,
>> +						create->flags,
>> +						&create->count,
>> +						requested_planes,
>> +						requested_sizes);
>>  }
>>  EXPORT_SYMBOL_GPL(vb2_create_bufs);
>>  
>> @@ -969,11 +983,12 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
>>  	int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
>>  
>>  	fill_buf_caps(vdev->queue, &p->capabilities);
>> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>>  	if (res)
>>  		return res;
>>  	if (vb2_queue_is_busy(vdev, file))
>>  		return -EBUSY;
>> -	res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
>> +	res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &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)
>> @@ -991,6 +1006,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
>>  
>>  	p->index = vdev->queue->num_buffers;
>>  	fill_buf_caps(vdev->queue, &p->capabilities);
>> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>>  	/*
>>  	 * If count == 0, then just check if memory and type are valid.
>>  	 * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> index a99e82ec9ab6..593bcf6c3735 100644
>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> @@ -246,6 +246,9 @@ struct v4l2_format32 {
>>   * @memory:	buffer memory type
>>   * @format:	frame format, for which buffers are requested
>>   * @capabilities: capabilities of this buffer type.
>> + * @flags:	additional buffer management attributes (ignored unless the
>> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
>> + *		configured for MMAP streaming I/O).
>>   * @reserved:	future extensions
>>   */
>>  struct v4l2_create_buffers32 {
>> @@ -254,7 +257,8 @@ struct v4l2_create_buffers32 {
>>  	__u32			memory;	/* enum v4l2_memory */
>>  	struct v4l2_format32	format;
>>  	__u32			capabilities;
>> -	__u32			reserved[7];
>> +	__u32			flags;
>> +	__u32			reserved[6];
>>  };
>>  
>>  static int __bufsize_v4l2_format(struct v4l2_format32 __user *p32, u32 *size)
>> @@ -355,7 +359,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers __user *p64,
>>  {
>>  	if (!access_ok(p32, sizeof(*p32)) ||
>>  	    copy_in_user(p64, p32,
>> -			 offsetof(struct v4l2_create_buffers32, format)))
>> +			 offsetof(struct v4l2_create_buffers32, format)) ||
>> +	    assign_in_user(&p64->flags, &p32->flags))
>>  		return -EFAULT;
>>  	return __get_v4l2_format32(&p64->format, &p32->format,
>>  				   aux_buf, aux_space);
>> @@ -417,6 +422,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers __user *p64,
>>  	    copy_in_user(p32, p64,
>>  			 offsetof(struct v4l2_create_buffers32, format)) ||
>>  	    assign_in_user(&p32->capabilities, &p64->capabilities) ||
>> +	    assign_in_user(&p32->flags, &p64->flags) ||
>>  	    copy_in_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
>>  		return -EFAULT;
>>  	return __put_v4l2_format32(&p64->format, &p32->format);
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 2322f08a98be..02bfef0da76d 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -2038,9 +2038,6 @@ 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);
>>  }
>>  
>> @@ -2080,7 +2077,7 @@ 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 34ba1017b89b..fec2607a07e3 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -946,7 +946,10 @@ 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 */
>> @@ -2450,6 +2453,9 @@ struct v4l2_dbg_chip_info {
>>   * @memory:	enum v4l2_memory; buffer memory type
>>   * @format:	frame format, for which buffers are requested
>>   * @capabilities: capabilities of this buffer type.
>> + * @flags:	additional buffer management attributes (ignored unless the
>> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
>> + *		and configured for MMAP streaming I/O).
>>   * @reserved:	future extensions
>>   */
>>  struct v4l2_create_buffers {
>> @@ -2458,7 +2464,8 @@ struct v4l2_create_buffers {
>>  	__u32			memory;
>>  	struct v4l2_format	format;
>>  	__u32			capabilities;
>> -	__u32			reserved[7];
>> +	__u32			flags;
>> +	__u32			reserved[6];
>>  };
>>  
>>  /*
>> -------------------------------------------------------------------------------
>>
>>
>> Git bisection log:
>>
>> -------------------------------------------------------------------------------
>> git bisect start
>> # good: [2630e1bb0948c3134c6f22ad275ae27cc6023532] media: rkvdec: Fix H264 scaling list order
>> git bisect good 2630e1bb0948c3134c6f22ad275ae27cc6023532
>> # bad: [e30cc79cc80fd919b697a15c5000d9f57487de8e] media: media-request: Fix crash if memory allocation fails
>> git bisect bad e30cc79cc80fd919b697a15c5000d9f57487de8e
>> # good: [cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
>> git bisect good cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2
>> # good: [3b69e8b4571125bec1f77f886174fe6cab6b9d75] Merge tag 'sh-for-5.8' of git://git.libc.org/linux-sh
>> git bisect good 3b69e8b4571125bec1f77f886174fe6cab6b9d75
>> # good: [3ed740841bf94a8028ec44164d84f9af9bd552fd] maccess: remove duplicate kerneldoc comments
>> git bisect good 3ed740841bf94a8028ec44164d84f9af9bd552fd
>> # good: [2ab70319bc1f79228da4dce7b9d604740c9beeef] nmi, tracing: Make hardware latency tracing noinstr safe
>> git bisect good 2ab70319bc1f79228da4dce7b9d604740c9beeef
>> # good: [df2fbf5bfa0e7fff8b4784507e4d68f200454318] Merge tag 'thermal-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux
>> git bisect good df2fbf5bfa0e7fff8b4784507e4d68f200454318
>> # good: [91fa58840ae22cbf6d7c505ce6564c4c48f29af3] Merge branch 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
>> git bisect good 91fa58840ae22cbf6d7c505ce6564c4c48f29af3
>> # good: [bc139119a1708ae3db1ebb379630f286e28d06e8] net: ethernet: ti: ale: fix allmulti for nu type ale
>> git bisect good bc139119a1708ae3db1ebb379630f286e28d06e8
>> # good: [157282a5c6273976b31cf4ba4b1c46663f6519d1] media: s5k6a3: Fix runtime PM imbalance on error
>> git bisect good 157282a5c6273976b31cf4ba4b1c46663f6519d1
>> # bad: [286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc] media: videodev2.h: add V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL flag
>> git bisect bad 286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc
>> # good: [ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e] media: videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>> git bisect good ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e
>> # bad: [d4db5eb57cab049d378fbfb7ee842857009a8679] media: videobuf2: add begin/end cpu_access callbacks to dma-sg
>> git bisect bad d4db5eb57cab049d378fbfb7ee842857009a8679
>> # bad: [38a417e88aad1e5ad5ff2647d4cd26040b567fc3] media: videobuf2: factor out planes prepare/finish functions
>> git bisect bad 38a417e88aad1e5ad5ff2647d4cd26040b567fc3
>> # bad: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>> git bisect bad 1e0b2318fa75d186ee0d2be31843ce867385fcc4
>> # good: [7b4b45555c79db03dad8192e6ef85cb30236827b] media: videobuf2: add queue memory consistency parameter
>> git bisect good 7b4b45555c79db03dad8192e6ef85cb30236827b
>> # first bad commit: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>> -------------------------------------------------------------------------------
>>
> 

Re: media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin

[Guillaume Tucker]

On 26/06/2020 08:02, Hans Verkuil wrote:
> Hi Guillaume,
> 
> You need to update v4l-utils to the latest version from our git master branch.
> 
> The reserved field in reqbufs is now in use as a flags field, so it is no longer
> zero. The compliance test has been updated accordingly in the v4l-utils git repo.

I see, thanks.  It's getting updated today.

Guillaume


> On 26/06/2020 08:56, Guillaume Tucker wrote:
>> Please see the bisection report below about a regression in
>> v4l2-compliance with uvcvideo:
>>
>> [   25.495039] uvcvideo: Failed to query (SET_CUR) UVC control 10 on unit 2: -32 (exp. 2).
>> 		fail: v4l2-test-buffers.cpp(680): check_0(reqbufs.reserved, sizeof(reqbufs.reserved))
>> 	test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: FAIL
>>
>>
>> as seen in the full job log:
>>
>>     https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html#L1713
>>
>> with a few more details about the regression here:
>>
>>     https://kernelci.org/test/case/id/5ef23169140826f73d97bf51/
>>
>> and the same test case failure also seen with vivid:
>>
>>     https://kernelci.org/test/case/id/5ef23699f641f7b3e597bf3f/
>>
>>
>> The bisection actually ran a couple of days ago but there was an
>> email error when sending the report, so I'm sending it by hand
>> now.  I hope the issue hasn't spread too widely already, I know
>> it's also affecting linux-next.
>>
>> Guillaume
>>
>>
>> On 25/06/2020 23:19, kernelci.org bot wrote:
>>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>>> * This automated bisection report was sent to you on the basis  *
>>> * that you may be involved with the breaking commit it has      *
>>> * found.  No manual investigation has been done to verify it,   *
>>> * and the root cause of the problem may be somewhere else.      *
>>> *                                                               *
>>> * If you do send a fix, please include this trailer:            *
>>> *   Reported-by: "kernelci.org bot" <bot@kernelci.org>          *
>>> *                                                               *
>>> * Hope this helps!                                              *
>>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>>>
>>> media/master bisection: v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF on rk3399-gru-kevin
>>>
>>> Summary:
>>>   Start:      e30cc79cc80f media: media-request: Fix crash if memory allocation fails
>>>   Plain log:  https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.txt
>>>   HTML log:   https://storage.kernelci.org/media/master/v5.8-rc1-64-ge30cc79cc80f/arm64/defconfig/gcc-8/lab-collabora/v4l2-compliance-uvc-rk3399-gru-kevin.html
>>>   Result:     1e0b2318fa75 media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>>
>>> Checks:
>>>   revert:     PASS
>>>   verify:     PASS
>>>
>>> Parameters:
>>>   Tree:       media
>>>   URL:        https://git.linuxtv.org/media_tree.git
>>>   Branch:     master
>>>   Target:     rk3399-gru-kevin
>>>   CPU arch:   arm64
>>>   Lab:        lab-collabora
>>>   Compiler:   gcc-8
>>>   Config:     defconfig
>>>   Test case:  v4l2-compliance-uvc.Buffer-ioctls-Input-0.VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF
>>>
>>> Breaking commit found:
>>>
>>> -------------------------------------------------------------------------------
>>> commit 1e0b2318fa75d186ee0d2be31843ce867385fcc4
>>> Author: Sergey Senozhatsky <senozhatsky@chromium.org>
>>> Date:   Thu May 14 18:01:45 2020 +0200
>>>
>>>     media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>>     
>>>     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.
>>>     
>>>     = CREATE_BUFS32
>>>     
>>>       struct v4l2_create_buffers32 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>
>>>     Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>>>     Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
>>>
>>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>>> index e1afc5b504c2..f2a702870fad 100644
>>> --- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>>> +++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
>>> @@ -121,7 +121,12 @@ 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`.
>>> +
>>> +    * - __u32
>>> +      - ``reserved``\ [6]
>>>        - A place holder for future extensions. Drivers and applications
>>>  	must set the array to zero.
>>>  
>>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>>> index 96a59793d857..75d894d9c36c 100644
>>> --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>>> +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
>>> @@ -112,10 +112,17 @@ 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.
>>> +    * - union {
>>> +      - (anonymous)
>>> +    * - __u32
>>> +      - ``flags``
>>> +      - Specifies additional buffer management attributes.
>>> +	See :ref:`memory-flags`.
>>>      * - __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-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>>> index 0fdcf90330df..626c4db5134c 100644
>>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>>> @@ -694,6 +694,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
>>>  	unsigned int i;
>>>  	int ret;
>>>  
>>> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
>>> +		consistent_mem = false;
>>> +
>>>  	if (q->streaming) {
>>>  		dprintk(1, "streaming active\n");
>>>  		return -EBUSY;
>>> @@ -837,6 +840,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
>>>  	bool consistent_mem = true;
>>>  	int ret;
>>>  
>>> +	if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
>>> +		consistent_mem = false;
>>> +
>>>  	if (q->num_buffers == VB2_MAX_FRAME) {
>>>  		dprintk(1, "maximum number of buffers already allocated\n");
>>>  		return -ENOBUFS;
>>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> index 26a3ec333bb7..559a229cac41 100644
>>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> @@ -718,12 +718,22 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
>>>  #endif
>>>  }
>>>  
>>> +static void clear_consistency_attr(struct vb2_queue *q,
>>> +				   int memory,
>>> +				   unsigned int *flags)
>>> +{
>>> +	if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP)
>>> +		*flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
>>> +}
>>> +
>>>  int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
>>>  {
>>>  	int ret = vb2_verify_memory_type(q, req->memory, req->type);
>>>  
>>>  	fill_buf_caps(q, &req->capabilities);
>>> -	return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
>>> +	clear_consistency_attr(q, req->memory, &req->flags);
>>> +	return ret ? ret : vb2_core_reqbufs(q, req->memory,
>>> +					    req->flags, &req->count);
>>>  }
>>>  EXPORT_SYMBOL_GPL(vb2_reqbufs);
>>>  
>>> @@ -755,6 +765,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>>>  	unsigned i;
>>>  
>>>  	fill_buf_caps(q, &create->capabilities);
>>> +	clear_consistency_attr(q, create->memory, &create->flags);
>>>  	create->index = q->num_buffers;
>>>  	if (create->count == 0)
>>>  		return ret != -EBUSY ? ret : 0;
>>> @@ -797,8 +808,11 @@ 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, 0,
>>> -		&create->count, requested_planes, requested_sizes);
>>> +	return ret ? ret : vb2_core_create_bufs(q, create->memory,
>>> +						create->flags,
>>> +						&create->count,
>>> +						requested_planes,
>>> +						requested_sizes);
>>>  }
>>>  EXPORT_SYMBOL_GPL(vb2_create_bufs);
>>>  
>>> @@ -969,11 +983,12 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
>>>  	int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
>>>  
>>>  	fill_buf_caps(vdev->queue, &p->capabilities);
>>> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>>>  	if (res)
>>>  		return res;
>>>  	if (vb2_queue_is_busy(vdev, file))
>>>  		return -EBUSY;
>>> -	res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
>>> +	res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &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)
>>> @@ -991,6 +1006,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
>>>  
>>>  	p->index = vdev->queue->num_buffers;
>>>  	fill_buf_caps(vdev->queue, &p->capabilities);
>>> +	clear_consistency_attr(vdev->queue, p->memory, &p->flags);
>>>  	/*
>>>  	 * If count == 0, then just check if memory and type are valid.
>>>  	 * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
>>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>>> index a99e82ec9ab6..593bcf6c3735 100644
>>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>>> @@ -246,6 +246,9 @@ struct v4l2_format32 {
>>>   * @memory:	buffer memory type
>>>   * @format:	frame format, for which buffers are requested
>>>   * @capabilities: capabilities of this buffer type.
>>> + * @flags:	additional buffer management attributes (ignored unless the
>>> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
>>> + *		configured for MMAP streaming I/O).
>>>   * @reserved:	future extensions
>>>   */
>>>  struct v4l2_create_buffers32 {
>>> @@ -254,7 +257,8 @@ struct v4l2_create_buffers32 {
>>>  	__u32			memory;	/* enum v4l2_memory */
>>>  	struct v4l2_format32	format;
>>>  	__u32			capabilities;
>>> -	__u32			reserved[7];
>>> +	__u32			flags;
>>> +	__u32			reserved[6];
>>>  };
>>>  
>>>  static int __bufsize_v4l2_format(struct v4l2_format32 __user *p32, u32 *size)
>>> @@ -355,7 +359,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers __user *p64,
>>>  {
>>>  	if (!access_ok(p32, sizeof(*p32)) ||
>>>  	    copy_in_user(p64, p32,
>>> -			 offsetof(struct v4l2_create_buffers32, format)))
>>> +			 offsetof(struct v4l2_create_buffers32, format)) ||
>>> +	    assign_in_user(&p64->flags, &p32->flags))
>>>  		return -EFAULT;
>>>  	return __get_v4l2_format32(&p64->format, &p32->format,
>>>  				   aux_buf, aux_space);
>>> @@ -417,6 +422,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers __user *p64,
>>>  	    copy_in_user(p32, p64,
>>>  			 offsetof(struct v4l2_create_buffers32, format)) ||
>>>  	    assign_in_user(&p32->capabilities, &p64->capabilities) ||
>>> +	    assign_in_user(&p32->flags, &p64->flags) ||
>>>  	    copy_in_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
>>>  		return -EFAULT;
>>>  	return __put_v4l2_format32(&p64->format, &p32->format);
>>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> index 2322f08a98be..02bfef0da76d 100644
>>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> @@ -2038,9 +2038,6 @@ 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);
>>>  }
>>>  
>>> @@ -2080,7 +2077,7 @@ 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 34ba1017b89b..fec2607a07e3 100644
>>> --- a/include/uapi/linux/videodev2.h
>>> +++ b/include/uapi/linux/videodev2.h
>>> @@ -946,7 +946,10 @@ 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 */
>>> @@ -2450,6 +2453,9 @@ struct v4l2_dbg_chip_info {
>>>   * @memory:	enum v4l2_memory; buffer memory type
>>>   * @format:	frame format, for which buffers are requested
>>>   * @capabilities: capabilities of this buffer type.
>>> + * @flags:	additional buffer management attributes (ignored unless the
>>> + *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
>>> + *		and configured for MMAP streaming I/O).
>>>   * @reserved:	future extensions
>>>   */
>>>  struct v4l2_create_buffers {
>>> @@ -2458,7 +2464,8 @@ struct v4l2_create_buffers {
>>>  	__u32			memory;
>>>  	struct v4l2_format	format;
>>>  	__u32			capabilities;
>>> -	__u32			reserved[7];
>>> +	__u32			flags;
>>> +	__u32			reserved[6];
>>>  };
>>>  
>>>  /*
>>> -------------------------------------------------------------------------------
>>>
>>>
>>> Git bisection log:
>>>
>>> -------------------------------------------------------------------------------
>>> git bisect start
>>> # good: [2630e1bb0948c3134c6f22ad275ae27cc6023532] media: rkvdec: Fix H264 scaling list order
>>> git bisect good 2630e1bb0948c3134c6f22ad275ae27cc6023532
>>> # bad: [e30cc79cc80fd919b697a15c5000d9f57487de8e] media: media-request: Fix crash if memory allocation fails
>>> git bisect bad e30cc79cc80fd919b697a15c5000d9f57487de8e
>>> # good: [cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
>>> git bisect good cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2
>>> # good: [3b69e8b4571125bec1f77f886174fe6cab6b9d75] Merge tag 'sh-for-5.8' of git://git.libc.org/linux-sh
>>> git bisect good 3b69e8b4571125bec1f77f886174fe6cab6b9d75
>>> # good: [3ed740841bf94a8028ec44164d84f9af9bd552fd] maccess: remove duplicate kerneldoc comments
>>> git bisect good 3ed740841bf94a8028ec44164d84f9af9bd552fd
>>> # good: [2ab70319bc1f79228da4dce7b9d604740c9beeef] nmi, tracing: Make hardware latency tracing noinstr safe
>>> git bisect good 2ab70319bc1f79228da4dce7b9d604740c9beeef
>>> # good: [df2fbf5bfa0e7fff8b4784507e4d68f200454318] Merge tag 'thermal-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux
>>> git bisect good df2fbf5bfa0e7fff8b4784507e4d68f200454318
>>> # good: [91fa58840ae22cbf6d7c505ce6564c4c48f29af3] Merge branch 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
>>> git bisect good 91fa58840ae22cbf6d7c505ce6564c4c48f29af3
>>> # good: [bc139119a1708ae3db1ebb379630f286e28d06e8] net: ethernet: ti: ale: fix allmulti for nu type ale
>>> git bisect good bc139119a1708ae3db1ebb379630f286e28d06e8
>>> # good: [157282a5c6273976b31cf4ba4b1c46663f6519d1] media: s5k6a3: Fix runtime PM imbalance on error
>>> git bisect good 157282a5c6273976b31cf4ba4b1c46663f6519d1
>>> # bad: [286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc] media: videodev2.h: add V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL flag
>>> git bisect bad 286cf7d3a99e1ca8c1d8e674b9a98f2dbe8520dc
>>> # good: [ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e] media: videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>> git bisect good ac53503ee38a1ffbc47c7cca6cbfc48ba9c65c5e
>>> # bad: [d4db5eb57cab049d378fbfb7ee842857009a8679] media: videobuf2: add begin/end cpu_access callbacks to dma-sg
>>> git bisect bad d4db5eb57cab049d378fbfb7ee842857009a8679
>>> # bad: [38a417e88aad1e5ad5ff2647d4cd26040b567fc3] media: videobuf2: factor out planes prepare/finish functions
>>> git bisect bad 38a417e88aad1e5ad5ff2647d4cd26040b567fc3
>>> # bad: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>> git bisect bad 1e0b2318fa75d186ee0d2be31843ce867385fcc4
>>> # good: [7b4b45555c79db03dad8192e6ef85cb30236827b] media: videobuf2: add queue memory consistency parameter
>>> git bisect good 7b4b45555c79db03dad8192e6ef85cb30236827b
>>> # first bad commit: [1e0b2318fa75d186ee0d2be31843ce867385fcc4] media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
>>> -------------------------------------------------------------------------------
>>>
>>
>