Em Thu, 21 Mar 2024 15:24:43 +0100 Hans Verkuil <hverkuil-cisco@xxxxxxxxx> escreveu: > On 21/03/2024 3:14 pm, Mauro Carvalho Chehab wrote: > > Em Thu, 14 Mar 2024 16:32:24 +0100 > > Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx> escreveu: > > > >> VIDIOC_REMOVE_BUFS ioctl allows to remove buffers from a queue. > >> The number of buffers to remove in given by count field of > >> struct v4l2_remove_buffers and the range start at the index > >> specified in the same structure. > >> > >> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx> > >> --- > >> changes in version 21: > >> - Be more careful about checking remove_bufs type field vs queue type. > >> - Add documentation about type checking error. > >> - Always set capabilities flags field. > >> > >> .../userspace-api/media/v4l/user-func.rst | 1 + > >> .../media/v4l/vidioc-remove-bufs.rst | 85 +++++++++++++++++++ > >> .../media/v4l/vidioc-reqbufs.rst | 1 + > >> .../media/common/videobuf2/videobuf2-core.c | 38 +++++++++ > >> .../media/common/videobuf2/videobuf2-v4l2.c | 20 ++++- > >> drivers/media/v4l2-core/v4l2-dev.c | 3 + > >> drivers/media/v4l2-core/v4l2-ioctl.c | 30 +++++++ > >> include/media/v4l2-ioctl.h | 4 + > >> include/media/videobuf2-core.h | 10 +++ > >> include/media/videobuf2-v4l2.h | 2 + > >> include/uapi/linux/videodev2.h | 17 ++++ > >> 11 files changed, 210 insertions(+), 1 deletion(-) > >> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-remove-bufs.rst > >> > >> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst > >> index 15ff0bf7bbe6..6f661138801c 100644 > >> --- a/Documentation/userspace-api/media/v4l/user-func.rst > >> +++ b/Documentation/userspace-api/media/v4l/user-func.rst > >> @@ -62,6 +62,7 @@ Function Reference > >> vidioc-query-dv-timings > >> vidioc-querystd > >> vidioc-reqbufs > >> + vidioc-remove-bufs > >> vidioc-s-hw-freq-seek > >> vidioc-streamon > >> vidioc-subdev-enum-frame-interval > >> diff --git a/Documentation/userspace-api/media/v4l/vidioc-remove-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-remove-bufs.rst > >> new file mode 100644 > >> index 000000000000..0cbc8c7313b7 > >> --- /dev/null > >> +++ b/Documentation/userspace-api/media/v4l/vidioc-remove-bufs.rst > >> @@ -0,0 +1,85 @@ > >> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later > >> +.. c:namespace:: V4L > >> + > >> +.. _VIDIOC_REMOVE_BUFS: > >> + > >> +************************ > >> +ioctl VIDIOC_REMOVE_BUFS > >> +************************ > >> + > >> +Name > >> +==== > >> + > >> +VIDIOC_REMOVE_BUFS - Removes buffers from a queue > >> + > >> +Synopsis > >> +======== > >> + > >> +.. c:macro:: VIDIOC_REMOVE_BUFS > >> + > >> +``int ioctl(int fd, VIDIOC_REMOVE_BUFS, struct v4l2_remove_buffers *argp)`` > >> + > >> +Arguments > >> +========= > >> + > >> +``fd`` > >> + File descriptor returned by :c:func:`open()`. > >> + > >> +``argp`` > >> + Pointer to struct :c:type:`v4l2_remove_buffers`. > >> + > >> +Description > >> +=========== > >> + > >> +Applications can optionally call the :ref:`VIDIOC_REMOVE_BUFS` ioctl to > >> +remove buffers from a queue. > >> +:ref:`VIDIOC_CREATE_BUFS` ioctl support is mandatory to enable :ref:`VIDIOC_REMOVE_BUFS`. > >> +This ioctl is available if the ``V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS`` capability > >> +is set on the queue when :c:func:`VIDIOC_REQBUFS` or :c:func:`VIDIOC_CREATE_BUFS` > >> +are invoked. > >> + > >> +.. c:type:: v4l2_remove_buffers > >> + > >> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| > >> + > >> +.. flat-table:: struct v4l2_remove_buffers > >> + :header-rows: 0 > >> + :stub-columns: 0 > >> + :widths: 1 1 2 > >> + > >> + * - __u32 > >> + - ``index`` > >> + - The starting buffer index to remove. This field is ignored if count == 0. > >> + * - __u32 > >> + - ``count`` > >> + - The number of buffers to be removed with indices 'index' until 'index + count - 1'. > >> + All buffers in this range must be valid and in DEQUEUED state. > >> + :ref:`VIDIOC_REMOVE_BUFS` will always check the validity of ``type`, if it is > >> + invalid it returns ``EINVAL`` error code. > >> + If count is set to 0 :ref:`VIDIOC_REMOVE_BUFS` will do nothing and return 0. > >> + * - __u32 > >> + - ``type`` > >> + - Type of the stream or buffers, this is the same as the struct > >> + :c:type:`v4l2_format` ``type`` field. See > >> + :c:type:`v4l2_buf_type` for valid values. > >> + * - __u32 > >> + - ``reserved``\ [13] > >> + - A place holder for future extensions. Drivers and applications > >> + must set the array to zero. > >> + > >> +Return Value > >> +============ > >> + > >> +On success 0 is returned, on error -1 and the ``errno`` variable is set > >> +appropriately. The generic error codes are described at the > >> +:ref:`Generic Error Codes <gen-errors>` chapter. > > > > It is not enough to just return an error code. it should also describe > > what will be the expected behavior after the call. Something like: > > > > If an error occurs, no buffers will be freed and one of the > > error codes below will be returned: > > That's good to have. That is indeed not stated explicitly. > > > > >> + > >> +EBUSY > >> + File I/O is in progress. > >> + One or more of the buffers in the range ``index`` to ``index + count - 1`` are not > >> + in DEQUEUED state. > >> + > >> +EINVAL > >> + One or more of the buffers in the range ``index`` to ``index + count - 1`` do not > >> + exist in the queue. > >> + The buffer type (``type`` field) is not valid. > > > > IMO, it needs also another error code: as there's a minimal number of > > buffers to be queued (let's say, 2), what happens if there are currently > > 3 buffers allocated and an ioctl is called to free 2 buffers? > > > > IMO, it shall return an error code and not free any buffers. > > Note the requirement that all buffers you want to remove have to be in dequeued > state. So you can never remove buffers that are still in flight. An attempt to > do that results in EBUSY. > > So there is no need for an other error code. > > > > > The best would be to return a code different than EINVAL. Maybe E2BIG? > > > >> diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst > >> index 0b3a41a45d05..bbc22dd76032 100644 > >> --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst > >> +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst > >> @@ -121,6 +121,7 @@ aborting or finishing any DMA in progress, an implicit > >> .. _V4L2-BUF-CAP-SUPPORTS-M2M-HOLD-CAPTURE-BUF: > >> .. _V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS: > >> .. _V4L2-BUF-CAP-SUPPORTS-MAX-NUM-BUFFERS: > >> +.. _V4L2-BUF-CAP-SUPPORTS-REMOVE-BUFS: > >> > >> .. raw:: latex > >> > >> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > >> index 009cea95d662..0b2b48e1b2df 100644 > >> --- a/drivers/media/common/videobuf2/videobuf2-core.c > >> +++ b/drivers/media/common/videobuf2/videobuf2-core.c > >> @@ -1691,6 +1691,44 @@ int vb2_core_prepare_buf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb) > >> } > >> EXPORT_SYMBOL_GPL(vb2_core_prepare_buf); > >> > >> +int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count) > >> +{ > >> + unsigned int i, ret = 0; > >> + unsigned int q_num_bufs = vb2_get_num_buffers(q); > >> + > >> + if (count == 0) > >> + return 0; > >> + > >> + if (count > q_num_bufs) > >> + return -EINVAL; > > > > It also needs: > > > > if (q_num_bufs - count < q->min_reqbufs_allocation && q_num_bufs != count) > > return <some error code>; > > > > e. g. it shall not accept keeping, for instance, just one buffer allocated. > > That's perfectly fine. The min_reqbufs_allocation is specific to VIDIOC_REQBUFS > (hence the name). If you use CREATE_BUFS/REMOVE_BUFS, then you are fully responsible > for allocating and removing buffers. > > This is something that was discussed in earlier revisions of this series. > > It is actually rather ugly that REQBUFS does this, but we need to keep that behavior > since that's how REQBUFS worked historically. > > VIDIOC_CREATE_BUFS was never affected by this, so if you want to allocate N > buffers with CREATE_BUFS, then you'll never get more than N buffers (you might get > less, of course). OK. So, after doing the documentation change, feel free to add: Reviewed-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> > > Regards, > > Hans > > > > >> + > >> + if (start > q->max_num_buffers - count) > >> + return -EINVAL; > >> + > >> + mutex_lock(&q->mmap_lock); > >> + > >> + /* Check that all buffers in the range exist */ > >> + for (i = start; i < start + count; i++) { > >> + struct vb2_buffer *vb = vb2_get_buffer(q, i); > >> + > >> + if (!vb) { > >> + ret = -EINVAL; > >> + goto unlock; > >> + } > >> + if (vb->state != VB2_BUF_STATE_DEQUEUED) { > >> + ret = -EBUSY; > >> + goto unlock; > >> + } > >> + } > >> + __vb2_queue_free(q, start, count); > >> + dprintk(q, 2, "%u buffers removed\n", count); > >> + > >> +unlock: > >> + mutex_unlock(&q->mmap_lock); > >> + return ret; > >> +} > >> +EXPORT_SYMBOL_GPL(vb2_core_remove_bufs); > >> + > >> /* > >> * vb2_start_streaming() - Attempt to start streaming. > >> * @q: videobuf2 queue > >> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c > >> index 03e8080a68a8..293f3d5f1c4e 100644 > >> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c > >> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c > >> @@ -685,7 +685,7 @@ static void vb2_set_flags_and_caps(struct vb2_queue *q, u32 memory, > >> *flags &= V4L2_MEMORY_FLAG_NON_COHERENT; > >> } > >> > >> - *caps = V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS; > >> + *caps |= V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS; > >> if (q->io_modes & VB2_MMAP) > >> *caps |= V4L2_BUF_CAP_SUPPORTS_MMAP; > >> if (q->io_modes & VB2_USERPTR) > >> @@ -1001,6 +1001,24 @@ EXPORT_SYMBOL_GPL(vb2_poll); > >> > >> /* vb2 ioctl helpers */ > >> > >> +int vb2_ioctl_remove_bufs(struct file *file, void *priv, > >> + struct v4l2_remove_buffers *d) > >> +{ > >> + struct video_device *vdev = video_devdata(file); > >> + > >> + if (vdev->queue->type != d->type) > >> + return -EINVAL; > >> + > >> + if (d->count == 0) > >> + return 0; > >> + > >> + if (vb2_queue_is_busy(vdev->queue, file)) > >> + return -EBUSY; > >> + > >> + return vb2_core_remove_bufs(vdev->queue, d->index, d->count); > >> +} > >> +EXPORT_SYMBOL_GPL(vb2_ioctl_remove_bufs); > >> + > >> int vb2_ioctl_reqbufs(struct file *file, void *priv, > >> struct v4l2_requestbuffers *p) > >> { > >> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c > >> index d13954bd31fd..e39e9742fdb5 100644 > >> --- a/drivers/media/v4l2-core/v4l2-dev.c > >> +++ b/drivers/media/v4l2-core/v4l2-dev.c > >> @@ -722,6 +722,9 @@ static void determine_valid_ioctls(struct video_device *vdev) > >> SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf); > >> SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon); > >> SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff); > >> + /* VIDIOC_CREATE_BUFS support is mandatory to enable VIDIOC_REMOVE_BUFS */ > >> + if (ops->vidioc_create_bufs) > >> + SET_VALID_IOCTL(ops, VIDIOC_REMOVE_BUFS, vidioc_remove_bufs); > >> } > >> > >> if (is_vid || is_vbi || is_meta) { > >> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > >> index 6e7b8b682d13..5aeff5519407 100644 > >> --- a/drivers/media/v4l2-core/v4l2-ioctl.c > >> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > >> @@ -489,6 +489,14 @@ static void v4l_print_create_buffers(const void *arg, bool write_only) > >> v4l_print_format(&p->format, write_only); > >> } > >> > >> +static void v4l_print_remove_buffers(const void *arg, bool write_only) > >> +{ > >> + const struct v4l2_remove_buffers *p = arg; > >> + > >> + pr_cont("type=%s, index=%u, count=%u\n", > >> + prt_names(p->type, v4l2_type_names), p->index, p->count); > >> +} > >> + > >> static void v4l_print_streamparm(const void *arg, bool write_only) > >> { > >> const struct v4l2_streamparm *p = arg; > >> @@ -2092,6 +2100,7 @@ static int v4l_overlay(const struct v4l2_ioctl_ops *ops, > >> static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops, > >> struct file *file, void *fh, void *arg) > >> { > >> + struct video_device *vfd = video_devdata(file); > >> struct v4l2_requestbuffers *p = arg; > >> int ret = check_fmt(file, p->type); > >> > >> @@ -2100,6 +2109,10 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops, > >> > >> memset_after(p, 0, flags); > >> > >> + p->capabilities = 0; > >> + if (is_valid_ioctl(vfd, VIDIOC_REMOVE_BUFS)) > >> + p->capabilities = V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS; > >> + > >> return ops->vidioc_reqbufs(file, fh, p); > >> } > >> > >> @@ -2133,6 +2146,7 @@ static int v4l_dqbuf(const struct v4l2_ioctl_ops *ops, > >> static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops, > >> struct file *file, void *fh, void *arg) > >> { > >> + struct video_device *vfd = video_devdata(file); > >> struct v4l2_create_buffers *create = arg; > >> int ret = check_fmt(file, create->format.type); > >> > >> @@ -2143,6 +2157,10 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops, > >> > >> v4l_sanitize_format(&create->format); > >> > >> + create->capabilities = 0; > >> + if (is_valid_ioctl(vfd, VIDIOC_REMOVE_BUFS)) > >> + create->capabilities = V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS; > >> + > >> ret = ops->vidioc_create_bufs(file, fh, create); > >> > >> if (create->format.type == V4L2_BUF_TYPE_VIDEO_CAPTURE || > >> @@ -2161,6 +2179,17 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops, > >> return ret ? ret : ops->vidioc_prepare_buf(file, fh, b); > >> } > >> > >> +static int v4l_remove_bufs(const struct v4l2_ioctl_ops *ops, > >> + struct file *file, void *fh, void *arg) > >> +{ > >> + struct v4l2_remove_buffers *remove = arg; > >> + > >> + if (ops->vidioc_remove_bufs) > >> + return ops->vidioc_remove_bufs(file, fh, remove); > >> + > >> + return -ENOTTY; > >> +} > >> + > >> static int v4l_g_parm(const struct v4l2_ioctl_ops *ops, > >> struct file *file, void *fh, void *arg) > >> { > >> @@ -2910,6 +2939,7 @@ static const struct v4l2_ioctl_info v4l2_ioctls[] = { > >> IOCTL_INFO(VIDIOC_ENUM_FREQ_BANDS, v4l_enum_freq_bands, v4l_print_freq_band, 0), > >> IOCTL_INFO(VIDIOC_DBG_G_CHIP_INFO, v4l_dbg_g_chip_info, v4l_print_dbg_chip_info, INFO_FL_CLEAR(v4l2_dbg_chip_info, match)), > >> IOCTL_INFO(VIDIOC_QUERY_EXT_CTRL, v4l_query_ext_ctrl, v4l_print_query_ext_ctrl, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_query_ext_ctrl, id)), > >> + IOCTL_INFO(VIDIOC_REMOVE_BUFS, v4l_remove_bufs, v4l_print_remove_buffers, INFO_FL_PRIO | INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_remove_buffers, type)), > >> }; > >> #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls) > >> > >> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h > >> index edb733f21604..bdbb7e542321 100644 > >> --- a/include/media/v4l2-ioctl.h > >> +++ b/include/media/v4l2-ioctl.h > >> @@ -163,6 +163,8 @@ struct v4l2_fh; > >> * :ref:`VIDIOC_CREATE_BUFS <vidioc_create_bufs>` ioctl > >> * @vidioc_prepare_buf: pointer to the function that implements > >> * :ref:`VIDIOC_PREPARE_BUF <vidioc_prepare_buf>` ioctl > >> + * @vidioc_remove_bufs: pointer to the function that implements > >> + * :ref:`VIDIOC_REMOVE_BUFS <vidioc_remove_bufs>` ioctl > >> * @vidioc_overlay: pointer to the function that implements > >> * :ref:`VIDIOC_OVERLAY <vidioc_overlay>` ioctl > >> * @vidioc_g_fbuf: pointer to the function that implements > >> @@ -422,6 +424,8 @@ struct v4l2_ioctl_ops { > >> struct v4l2_create_buffers *b); > >> int (*vidioc_prepare_buf)(struct file *file, void *fh, > >> struct v4l2_buffer *b); > >> + int (*vidioc_remove_bufs)(struct file *file, void *fh, > >> + struct v4l2_remove_buffers *d); > >> > >> int (*vidioc_overlay)(struct file *file, void *fh, unsigned int i); > >> int (*vidioc_g_fbuf)(struct file *file, void *fh, > >> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > >> index b9333e2c7797..955237ac503d 100644 > >> --- a/include/media/videobuf2-core.h > >> +++ b/include/media/videobuf2-core.h > >> @@ -870,6 +870,16 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, > >> */ > >> int vb2_core_prepare_buf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb); > >> > >> +/** > >> + * vb2_core_remove_bufs() - > >> + * @q: pointer to &struct vb2_queue with videobuf2 queue. > >> + * @start: first index of the range of buffers to remove. > >> + * @count: number of buffers to remove. > >> + * > >> + * Return: returns zero on success; an error code otherwise. > >> + */ > >> +int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count); > >> + > >> /** > >> * vb2_core_qbuf() - Queue a buffer from userspace > >> * > >> diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h > >> index 5a845887850b..77ce8238ab30 100644 > >> --- a/include/media/videobuf2-v4l2.h > >> +++ b/include/media/videobuf2-v4l2.h > >> @@ -334,6 +334,8 @@ int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); > >> int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); > >> int vb2_ioctl_expbuf(struct file *file, void *priv, > >> struct v4l2_exportbuffer *p); > >> +int vb2_ioctl_remove_bufs(struct file *file, void *priv, > >> + struct v4l2_remove_buffers *p); > >> > >> /* struct v4l2_file_operations helpers */ > >> > >> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > >> index a8015e5e7fa4..2663213b76a4 100644 > >> --- a/include/uapi/linux/videodev2.h > >> +++ b/include/uapi/linux/videodev2.h > >> @@ -1036,6 +1036,7 @@ struct v4l2_requestbuffers { > >> #define V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 5) > >> #define V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS (1 << 6) > >> #define V4L2_BUF_CAP_SUPPORTS_MAX_NUM_BUFFERS (1 << 7) > >> +#define V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS (1 << 8) > >> > >> /** > >> * struct v4l2_plane - plane info for multi-planar buffers > >> @@ -2624,6 +2625,20 @@ struct v4l2_create_buffers { > >> __u32 reserved[5]; > >> }; > >> > >> +/** > >> + * struct v4l2_remove_buffers - VIDIOC_REMOVE_BUFS argument > >> + * @index: the first buffer to be removed > >> + * @count: number of buffers to removed > >> + * @type: enum v4l2_buf_type > >> + * @reserved: future extensions > >> + */ > >> +struct v4l2_remove_buffers { > >> + __u32 index; > >> + __u32 count; > >> + __u32 type; > >> + __u32 reserved[13]; > >> +}; > >> + > >> /* > >> * I O C T L C O D E S F O R V I D E O D E V I C E S > >> * > >> @@ -2723,6 +2738,8 @@ struct v4l2_create_buffers { > >> #define VIDIOC_DBG_G_CHIP_INFO _IOWR('V', 102, struct v4l2_dbg_chip_info) > >> > >> #define VIDIOC_QUERY_EXT_CTRL _IOWR('V', 103, struct v4l2_query_ext_ctrl) > >> +#define VIDIOC_REMOVE_BUFS _IOWR('V', 104, struct v4l2_remove_buffers) > >> + > >> > >> /* Reminder: when adding new ioctls please add support for them to > >> drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */ > > > > > > > > Thanks, > > Mauro > Thanks, Mauro