VIDIOC_DELETE_BUFS ioctl allows to delete buffers from a queue.
The number of buffers to delete in given by count field of
struct v4l2_delete_buffers and the range start at the index
specified in the same structure.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
v6:
- Add lock in vb2_core_delete_buf()
- Fix typo and comments
- Add flags in VIDIOC_DELETE_BUFS decalaration
.../userspace-api/media/v4l/user-func.rst | 1 +
.../media/v4l/vidioc-delete-bufs.rst | 73 +++++++++++++++++++
.../media/common/videobuf2/videobuf2-core.c | 24 ++++++
.../media/common/videobuf2/videobuf2-v4l2.c | 38 +++++++++-
drivers/media/v4l2-core/v4l2-dev.c | 1 +
drivers/media/v4l2-core/v4l2-ioctl.c | 17 +++++
include/media/v4l2-ioctl.h | 4 +
include/media/videobuf2-core.h | 9 +++
include/media/videobuf2-v4l2.h | 11 +++
include/uapi/linux/videodev2.h | 16 ++++
10 files changed, 193 insertions(+), 1 deletion(-)
create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
index 15ff0bf7bbe6..3fd567695477 100644
--- a/Documentation/userspace-api/media/v4l/user-func.rst
+++ b/Documentation/userspace-api/media/v4l/user-func.rst
@@ -17,6 +17,7 @@ Function Reference
vidioc-dbg-g-chip-info
vidioc-dbg-g-register
vidioc-decoder-cmd
+ vidioc-delete-bufs
vidioc-dqevent
vidioc-dv-timings-cap
vidioc-encoder-cmd
diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
new file mode 100644
index 000000000000..a55fe6331fc8
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
@@ -0,0 +1,73 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: V4L
+
+.. _VIDIOC_DELETE_BUFS:
+
+************************
+ioctl VIDIOC_DELETE_BUFS
+************************
+
+Name
+====
+
+VIDIOC_DELETE_BUFS - Deletes buffers from a queue
+
+Synopsis
+========
+
+.. c:macro:: VIDIOC_DELETE_BUFs
+
+``int ioctl(int fd, VIDIOC_DELETE_BUFs, struct v4l2_delete_buffers *argp)``
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :c:func:`open()`.
+
+``argp``
+ Pointer to struct :c:type:`v4l2_delete_buffers`.
+
+Description
+===========
+
+Applications can optionally call the :ref:`VIDIOC_DELETE_BUFS` ioctl to
+delete buffers from a queue.
+
+.. c:type:: v4l2_delete_buffers
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
+
+.. flat-table:: struct v4l2_delete_buffers
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``index``
+ - The starting buffer index to delete.
+ * - __u32
+ - ``count``
+ - The number of buffers to be deleted.
+ * - __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.
+
+EBUSY
+ File I/O is in progress.
+
+EINVAL
+ The buffer ``index`` doesn't exist in the queue.
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index dc7f6b59d237..9edb2a1e95fc 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -1633,6 +1633,30 @@ 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_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb)
+{
+ mutex_lock(&q->mmap_lock);
+ if (vb->planes[0].mem_priv)
+ call_void_vb_qop(vb, buf_cleanup, vb);
+
+ /* Free MMAP buffers or release USERPTR buffers */
+ if (q->memory == VB2_MEMORY_MMAP)
+ __vb2_buf_mem_free(vb);
+ else if (q->memory == VB2_MEMORY_DMABUF)
+ __vb2_buf_dmabuf_put(vb);
+ else
+ __vb2_buf_userptr_put(vb);
+
+ vb2_queue_remove_buffer(q, vb);
+ mutex_unlock(&q->mmap_lock);
+
+ dprintk(q, 2, "buffer %d deleted\n", vb->index);
+ kfree(vb);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_core_delete_buf);
+
/*
* 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 8ba658ad9891..d0098f58a65c 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -385,7 +385,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
vb = vb2_get_buffer(q, b->index);
if (!vb) {
- dprintk(q, 1, "%s: buffer is NULL\n", opname);
+ dprintk(q, 1, "%s: buffer %u was deleted\n", opname, b->index);
return -EINVAL;
}
@@ -757,6 +757,42 @@ int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
}
EXPORT_SYMBOL_GPL(vb2_prepare_buf);
+int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d)
+{
+ struct vb2_buffer *vb;
+ unsigned int index;
+ int ret = 0;
+
+ if (d->index > q->num_buffers ||
+ d->count > q->num_buffers ||
+ (d->index + d->count) > q->num_buffers) {
+ return -EINVAL;
+ }
+
+ for (index = d->index; index < d->index + d->count; index++) {
+ vb = vb2_get_buffer(q, index);
+ if (!vb) {
+ dprintk(q, 1, "can't find the requested buffer\n");
+ ret = -EINVAL;
+ goto error;
+ }
+ if (vb->state != VB2_BUF_STATE_DEQUEUED) {
+ dprintk(q, 1, "can't delete non dequeued buffer index %d\n", vb->index);
+ ret = -EINVAL;
+ goto error;
+ }
+
+ ret = vb2_core_delete_buf(q, vb);
+ if (ret)
+ break;
+ }
+
+error:
+ d->index = index;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vb2_delete_bufs);
+
int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
{
unsigned requested_planes = 1;
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index f81279492682..215654fd6581 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -720,6 +720,7 @@ 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);
+ SET_VALID_IOCTL(ops, VIDIOC_DELETE_BUFS, vidioc_delete_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 f4d9d6279094..aac3a0ea0126 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -489,6 +489,13 @@ static void v4l_print_create_buffers(const void *arg, bool write_only)
v4l_print_format(&p->format, write_only);
}
+static void v4l_print_delete_buffers(const void *arg, bool write_only)
+{
+ const struct v4l2_delete_buffers *p = arg;
+
+ pr_cont("index=%d, count=%d\n", p->index, p->count);
+}
+
static void v4l_print_streamparm(const void *arg, bool write_only)
{
const struct v4l2_streamparm *p = arg;
@@ -2160,6 +2167,15 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
}
+static int v4l_delete_bufs(const struct v4l2_ioctl_ops *ops,
+ struct file *file, void *fh, void *arg)
+{
+ struct v4l2_delete_buffers *delete = arg;
+ int ret = check_fmt(file, delete->type);
+
+ return ret ? ret : ops->vidioc_delete_bufs(file, fh, delete);
+}
+
static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
struct file *file, void *fh, void *arg)
{
@@ -2909,6 +2925,7 @@ 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_DELETE_BUFS, v4l_delete_bufs, v4l_print_delete_buffers, INFO_FL_PRIO | INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_delete_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..55afbde54211 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_delete_bufs: pointer to the function that implements
+ * :ref:`VIDIOC_DELETE_BUFS <vidioc_delete_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_delete_bufs)(struct file *file, void *fh,
+ struct v4l2_delete_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 97153c69583f..e2c5ff31efd0 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -843,6 +843,15 @@ 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_delete_buf() -
+ * @q: pointer to &struct vb2_queue with videobuf2 queue.
+ * @vb: pointer to struct &vb2_buffer.
+ *
+ * Return: returns zero on success; an error code otherwise.
+ */
+int vb2_core_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb);
+
/**
* vb2_core_qbuf() - Queue a buffer from userspace
*
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
index 5a845887850b..2ef68fdf388f 100644
--- a/include/media/videobuf2-v4l2.h
+++ b/include/media/videobuf2-v4l2.h
@@ -118,6 +118,17 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
*/
int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
struct v4l2_buffer *b);
+/**
+ * vb2_delete_bufs() - Delete buffers from the queue
+ *
+ * @q: pointer to &struct vb2_queue with videobuf2 queue.
+ * @d: delete parameter, passed from userspace to
+ * &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver.
+ */
+int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d);
/**
* vb2_qbuf() - Queue a buffer from userspace
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 78260e5d9985..9cc7f570d995 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2616,6 +2616,20 @@ struct v4l2_create_buffers {
__u32 reserved[6];
};
+/**
+ * struct v4l2_delete_buffers - VIDIOC_DELETE_BUFS argument
+ * @index: the first buffer to be deleted
+ * @count: number of buffers to delete
+ * @type: enum v4l2_buf_type
+ * @reserved: future extensions
+ */
+struct v4l2_delete_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
*
@@ -2715,6 +2729,8 @@ 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_DELETE_BUFS _IOWR('V', 104, struct v4l2_delete_buffers)
+
/* Reminder: when adding new ioctls please add support for them to
drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
--
2.39.2On 01/09/2023 14:44, Benjamin Gaignard wrote:
> VIDIOC_DELETE_BUFS ioctl allows to delete buffers from a queue.
> The number of buffers to delete in given by count field of
> struct v4l2_delete_buffers and the range start at the index
> specified in the same structure.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> ---
> v6:
> - Add lock in vb2_core_delete_buf()
> - Fix typo and comments
> - Add flags in VIDIOC_DELETE_BUFS decalaration
>
> .../userspace-api/media/v4l/user-func.rst | 1 +
> .../media/v4l/vidioc-delete-bufs.rst | 73 +++++++++++++++++++
> .../media/common/videobuf2/videobuf2-core.c | 24 ++++++
> .../media/common/videobuf2/videobuf2-v4l2.c | 38 +++++++++-
> drivers/media/v4l2-core/v4l2-dev.c | 1 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 17 +++++
> include/media/v4l2-ioctl.h | 4 +
> include/media/videobuf2-core.h | 9 +++
> include/media/videobuf2-v4l2.h | 11 +++
> include/uapi/linux/videodev2.h | 16 ++++
> 10 files changed, 193 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>
> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
> index 15ff0bf7bbe6..3fd567695477 100644
> --- a/Documentation/userspace-api/media/v4l/user-func.rst
> +++ b/Documentation/userspace-api/media/v4l/user-func.rst
> @@ -17,6 +17,7 @@ Function Reference
> vidioc-dbg-g-chip-info
> vidioc-dbg-g-register
> vidioc-decoder-cmd
> + vidioc-delete-bufs
> vidioc-dqevent
> vidioc-dv-timings-cap
> vidioc-encoder-cmd
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
> new file mode 100644
> index 000000000000..a55fe6331fc8
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
> @@ -0,0 +1,73 @@
> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> +.. c:namespace:: V4L
> +
> +.. _VIDIOC_DELETE_BUFS:
> +
> +************************
> +ioctl VIDIOC_DELETE_BUFS
> +************************
> +
> +Name
> +====
> +
> +VIDIOC_DELETE_BUFS - Deletes buffers from a queue
> +
> +Synopsis
> +========
> +
> +.. c:macro:: VIDIOC_DELETE_BUFs
> +
> +``int ioctl(int fd, VIDIOC_DELETE_BUFs, struct v4l2_delete_buffers *argp)``
> +
> +Arguments
> +=========
> +
> +``fd``
> + File descriptor returned by :c:func:`open()`.
> +
> +``argp``
> + Pointer to struct :c:type:`v4l2_delete_buffers`.
> +
> +Description
> +===========
> +
> +Applications can optionally call the :ref:`VIDIOC_DELETE_BUFS` ioctl to
> +delete buffers from a queue.
> +
> +.. c:type:: v4l2_delete_buffers
> +
> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
> +
> +.. flat-table:: struct v4l2_delete_buffers
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 1 1 2
> +
> + * - __u32
> + - ``index``
> + - The starting buffer index to delete.
> + * - __u32
> + - ``count``
> + - The number of buffers to be deleted.
That's not quite correct. This function will delete the buffers with indices
index until index+count-1. And indices in that range have to be valid buffers,
i.e. you can't have already deleted buffers in that range.
Or should we allow that? It is a fair question.
All buffers also have to be in the DEQUEUED state.
The text above suggests that given the following valid indices:
0, 1, 3, 4 (so the buffer with index 2 was already deleted)
deleting 2 buffers from index 1 would delete buffers 1, 3. When in
fact it will attempt to delete buffers 1 and 2.
Also document explicitly that calling this with count=0 (and perhaps
index=0 as well?) can be used to check if this ioctl is supported.
> + * - __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.
What should happen if you delete ALL buffers with this call? I.e., the
equivalent to REQBUFS with count=0.
Thinking about this the main difference is that DELETE_BUFS can only delete
dequeued buffers and it does not stop streaming if all buffers are deleted.
So REQBUFS with count=0 (or a STREAMOFF) is still needed to officially stop
streaming and cancel the queue.
Basically REQBUFS with count=0 is almost the equivalent of calling STREAMOFF followed
by DELETE_BUFS for all buffers. Almost, but not quite: REQBUFS(0) also reports
if the queue is unbalanced, and it sets q->num_buffers to 0. And in vb2_ioctl_reqbufs
it will set vdev->queue->owner to NULL.
I am inclined to do the same if DELETE_BUFS deletes all buffers.
> +
> +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.
> +
> +EBUSY
> + File I/O is in progress.
> +
> +EINVAL
> + The buffer ``index`` doesn't exist in the queue.
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index dc7f6b59d237..9edb2a1e95fc 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -1633,6 +1633,30 @@ 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_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb)
> +{
> + mutex_lock(&q->mmap_lock);
> + if (vb->planes[0].mem_priv)
> + call_void_vb_qop(vb, buf_cleanup, vb);
> +
> + /* Free MMAP buffers or release USERPTR buffers */
> + if (q->memory == VB2_MEMORY_MMAP)
> + __vb2_buf_mem_free(vb);
> + else if (q->memory == VB2_MEMORY_DMABUF)
> + __vb2_buf_dmabuf_put(vb);
> + else
> + __vb2_buf_userptr_put(vb);
> +
> + vb2_queue_remove_buffer(q, vb);
> + mutex_unlock(&q->mmap_lock);
> +
> + dprintk(q, 2, "buffer %d deleted\n", vb->index);
> + kfree(vb);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vb2_core_delete_buf);
This is duplicating what already happens in __vb2_free_mem and __vb2_queue_free.
That code needs to be refactored.
What you want is a __vb2_delete_buffers(struct vb2_queue *q, unsigned int index, unsigned int buffers)
function that is called with mmap_lock held and that deletes buffers in the range 'index'
to 'index + count - 1'. Buffers may already be deleted.
__vb2_free_mem does almost do all of that already.
Then this new function can be called from __vb2_queue_free() and you can make
a vb2_core_delete_bufs() function that takes the lock and calls __vb2_delete_buffers.
Another note: currently __vb2_queue_free checks if any of the buffers had unbalanced
operations. That check needs to be moved to __vb2_delete_buffers as well otherwise
that would never be reported when using DELETE_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 8ba658ad9891..d0098f58a65c 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -385,7 +385,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
>
> vb = vb2_get_buffer(q, b->index);
> if (!vb) {
> - dprintk(q, 1, "%s: buffer is NULL\n", opname);
> + dprintk(q, 1, "%s: buffer %u was deleted\n", opname, b->index);
> return -EINVAL;
> }
>
> @@ -757,6 +757,42 @@ int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
> }
> EXPORT_SYMBOL_GPL(vb2_prepare_buf);
>
> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d)
> +{
> + struct vb2_buffer *vb;
> + unsigned int index;
> + int ret = 0;
> +
Add:
if (!d->count)
return 0;
(possibly also check if !d->index)
> + if (d->index > q->num_buffers ||
> should be >= here.
> + d->count > q->num_buffers ||
> + (d->index + d->count) > q->num_buffers) {
> + return -EINVAL;
> + }
Once we can delete buffers, how does that change the meaning of num_buffers?
Isn't this really max_buffer_index or something similar? But we probably also
still need to keep track of the actual number of buffers.
And create_bufs still allocated buffers from the last index onwards, it does
not attempt to reuse indices of previously deleted buffers.
There are a lot of drivers that use num_buffers, they will have to be audited.
This needs a lot more thought.
> +
> + for (index = d->index; index < d->index + d->count; index++) {
> + vb = vb2_get_buffer(q, index);
> + if (!vb) {
> + dprintk(q, 1, "can't find the requested buffer\n");
> + ret = -EINVAL;
> + goto error;
> + }
> + if (vb->state != VB2_BUF_STATE_DEQUEUED) {
> + dprintk(q, 1, "can't delete non dequeued buffer index %d\n", vb->index);
> + ret = -EINVAL;
> + goto error;
> + }
These checks have to take place first, then, if all is OK, you call vb2_core_delete_bufs.
Actually, thinking this over, I would move all these checks to vb2_core_delete_bufs.
It can all be put under the mmap_lock mutex to ensure nobody is messing around
with the queue while this takes place.
Note that when vb2_core_reqbufs() is called with count=0, then if it sees that
a buffer is still in use (mmaped), it will log a debug message that the buffers
are orphaned. We should keep that, I believe.
> +
> + ret = vb2_core_delete_buf(q, vb);
> + if (ret)
> + break;
> + }
> +
> +error:
> + d->index = index;
I wouldn't do this. I don't think this is useful.
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(vb2_delete_bufs);
> +
> int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> {
> unsigned requested_planes = 1;
> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> index f81279492682..215654fd6581 100644
> --- a/drivers/media/v4l2-core/v4l2-dev.c
> +++ b/drivers/media/v4l2-core/v4l2-dev.c
> @@ -720,6 +720,7 @@ 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);
> + SET_VALID_IOCTL(ops, VIDIOC_DELETE_BUFS, vidioc_delete_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 f4d9d6279094..aac3a0ea0126 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -489,6 +489,13 @@ static void v4l_print_create_buffers(const void *arg, bool write_only)
> v4l_print_format(&p->format, write_only);
> }
>
> +static void v4l_print_delete_buffers(const void *arg, bool write_only)
> +{
> + const struct v4l2_delete_buffers *p = arg;
> +
> + pr_cont("index=%d, count=%d\n", p->index, p->count);
Use %u since both args are unsigned.
> +}
> +
> static void v4l_print_streamparm(const void *arg, bool write_only)
> {
> const struct v4l2_streamparm *p = arg;
> @@ -2160,6 +2167,15 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
> return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
> }
>
> +static int v4l_delete_bufs(const struct v4l2_ioctl_ops *ops,
> + struct file *file, void *fh, void *arg)
> +{
> + struct v4l2_delete_buffers *delete = arg;
> + int ret = check_fmt(file, delete->type);
> +
> + return ret ? ret : ops->vidioc_delete_bufs(file, fh, delete);
> +}
> +
> static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
> struct file *file, void *fh, void *arg)
> {
> @@ -2909,6 +2925,7 @@ 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_DELETE_BUFS, v4l_delete_bufs, v4l_print_delete_buffers, INFO_FL_PRIO | INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_delete_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..55afbde54211 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_delete_bufs: pointer to the function that implements
> + * :ref:`VIDIOC_DELETE_BUFS <vidioc_delete_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_delete_bufs)(struct file *file, void *fh,
> + struct v4l2_delete_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 97153c69583f..e2c5ff31efd0 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -843,6 +843,15 @@ 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_delete_buf() -
> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
> + * @vb: pointer to struct &vb2_buffer.
> + *
> + * Return: returns zero on success; an error code otherwise.
> + */
> +int vb2_core_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb);
> +
> /**
> * vb2_core_qbuf() - Queue a buffer from userspace
> *
> diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
> index 5a845887850b..2ef68fdf388f 100644
> --- a/include/media/videobuf2-v4l2.h
> +++ b/include/media/videobuf2-v4l2.h
> @@ -118,6 +118,17 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
> */
> int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
> struct v4l2_buffer *b);
> +/**
> + * vb2_delete_bufs() - Delete buffers from the queue
> + *
> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
> + * @d: delete parameter, passed from userspace to
> + * &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver
> + *
> + * The return values from this function are intended to be directly returned
> + * from &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver.
> + */
> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d);
I'm missing the vb2_ioctl_delete_bufs function with a call to vb2_queue_is_busy().
>
> /**
> * vb2_qbuf() - Queue a buffer from userspace
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 78260e5d9985..9cc7f570d995 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -2616,6 +2616,20 @@ struct v4l2_create_buffers {
> __u32 reserved[6];
> };
>
> +/**
> + * struct v4l2_delete_buffers - VIDIOC_DELETE_BUFS argument
> + * @index: the first buffer to be deleted
> + * @count: number of buffers to delete
> + * @type: enum v4l2_buf_type
> + * @reserved: future extensions
> + */
> +struct v4l2_delete_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
> *
> @@ -2715,6 +2729,8 @@ 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_DELETE_BUFS _IOWR('V', 104, struct v4l2_delete_buffers)
> +
>
> /* Reminder: when adding new ioctls please add support for them to
> drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
You need much more extensive compliance checks for this, esp. mixing
create_bufs and delete_bufs. And test it with the test-media test script.
Regards,
Hans
Le 05/09/2023 à 10:17, Hans Verkuil a écrit :
> On 01/09/2023 14:44, Benjamin Gaignard wrote:
>> VIDIOC_DELETE_BUFS ioctl allows to delete buffers from a queue.
>> The number of buffers to delete in given by count field of
>> struct v4l2_delete_buffers and the range start at the index
>> specified in the same structure.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>> ---
>> v6:
>> - Add lock in vb2_core_delete_buf()
>> - Fix typo and comments
>> - Add flags in VIDIOC_DELETE_BUFS decalaration
>>
>> .../userspace-api/media/v4l/user-func.rst | 1 +
>> .../media/v4l/vidioc-delete-bufs.rst | 73 +++++++++++++++++++
>> .../media/common/videobuf2/videobuf2-core.c | 24 ++++++
>> .../media/common/videobuf2/videobuf2-v4l2.c | 38 +++++++++-
>> drivers/media/v4l2-core/v4l2-dev.c | 1 +
>> drivers/media/v4l2-core/v4l2-ioctl.c | 17 +++++
>> include/media/v4l2-ioctl.h | 4 +
>> include/media/videobuf2-core.h | 9 +++
>> include/media/videobuf2-v4l2.h | 11 +++
>> include/uapi/linux/videodev2.h | 16 ++++
>> 10 files changed, 193 insertions(+), 1 deletion(-)
>> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>>
>> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
>> index 15ff0bf7bbe6..3fd567695477 100644
>> --- a/Documentation/userspace-api/media/v4l/user-func.rst
>> +++ b/Documentation/userspace-api/media/v4l/user-func.rst
>> @@ -17,6 +17,7 @@ Function Reference
>> vidioc-dbg-g-chip-info
>> vidioc-dbg-g-register
>> vidioc-decoder-cmd
>> + vidioc-delete-bufs
>> vidioc-dqevent
>> vidioc-dv-timings-cap
>> vidioc-encoder-cmd
>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>> new file mode 100644
>> index 000000000000..a55fe6331fc8
>> --- /dev/null
>> +++ b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>> @@ -0,0 +1,73 @@
>> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
>> +.. c:namespace:: V4L
>> +
>> +.. _VIDIOC_DELETE_BUFS:
>> +
>> +************************
>> +ioctl VIDIOC_DELETE_BUFS
>> +************************
>> +
>> +Name
>> +====
>> +
>> +VIDIOC_DELETE_BUFS - Deletes buffers from a queue
>> +
>> +Synopsis
>> +========
>> +
>> +.. c:macro:: VIDIOC_DELETE_BUFs
>> +
>> +``int ioctl(int fd, VIDIOC_DELETE_BUFs, struct v4l2_delete_buffers *argp)``
>> +
>> +Arguments
>> +=========
>> +
>> +``fd``
>> + File descriptor returned by :c:func:`open()`.
>> +
>> +``argp``
>> + Pointer to struct :c:type:`v4l2_delete_buffers`.
>> +
>> +Description
>> +===========
>> +
>> +Applications can optionally call the :ref:`VIDIOC_DELETE_BUFS` ioctl to
>> +delete buffers from a queue.
>> +
>> +.. c:type:: v4l2_delete_buffers
>> +
>> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
>> +
>> +.. flat-table:: struct v4l2_delete_buffers
>> + :header-rows: 0
>> + :stub-columns: 0
>> + :widths: 1 1 2
>> +
>> + * - __u32
>> + - ``index``
>> + - The starting buffer index to delete.
>> + * - __u32
>> + - ``count``
>> + - The number of buffers to be deleted.
> That's not quite correct. This function will delete the buffers with indices
> index until index+count-1. And indices in that range have to be valid buffers,
> i.e. you can't have already deleted buffers in that range.
>
> Or should we allow that? It is a fair question.
>
> All buffers also have to be in the DEQUEUED state.
>
> The text above suggests that given the following valid indices:
>
> 0, 1, 3, 4 (so the buffer with index 2 was already deleted)
>
> deleting 2 buffers from index 1 would delete buffers 1, 3. When in
> fact it will attempt to delete buffers 1 and 2.
>
> Also document explicitly that calling this with count=0 (and perhaps
> index=0 as well?) can be used to check if this ioctl is supported.
I will do that.
>
>> + * - __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.
> What should happen if you delete ALL buffers with this call? I.e., the
> equivalent to REQBUFS with count=0.
>
> Thinking about this the main difference is that DELETE_BUFS can only delete
> dequeued buffers and it does not stop streaming if all buffers are deleted.
>
> So REQBUFS with count=0 (or a STREAMOFF) is still needed to officially stop
> streaming and cancel the queue.
>
> Basically REQBUFS with count=0 is almost the equivalent of calling STREAMOFF followed
> by DELETE_BUFS for all buffers. Almost, but not quite: REQBUFS(0) also reports
> if the queue is unbalanced, and it sets q->num_buffers to 0. And in vb2_ioctl_reqbufs
> it will set vdev->queue->owner to NULL.
>
> I am inclined to do the same if DELETE_BUFS deletes all buffers.
Unlike REQBUFS DELETE_BUFS can delete buffers while streaming so for me the ownership
should not change even if there is no more dequeued buffers.
For REQBUFS with count=0 means that the going stream is stopped so we can delete all the buffers
while DELETE_BUFS usage is to delete buffers while keeping the stream alive.
>
>> +
>> +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.
>> +
>> +EBUSY
>> + File I/O is in progress.
>> +
>> +EINVAL
>> + The buffer ``index`` doesn't exist in the queue.
>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>> index dc7f6b59d237..9edb2a1e95fc 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>> @@ -1633,6 +1633,30 @@ 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_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb)
>> +{
>> + mutex_lock(&q->mmap_lock);
>> + if (vb->planes[0].mem_priv)
>> + call_void_vb_qop(vb, buf_cleanup, vb);
>> +
>> + /* Free MMAP buffers or release USERPTR buffers */
>> + if (q->memory == VB2_MEMORY_MMAP)
>> + __vb2_buf_mem_free(vb);
>> + else if (q->memory == VB2_MEMORY_DMABUF)
>> + __vb2_buf_dmabuf_put(vb);
>> + else
>> + __vb2_buf_userptr_put(vb);
>> +
>> + vb2_queue_remove_buffer(q, vb);
>> + mutex_unlock(&q->mmap_lock);
>> +
>> + dprintk(q, 2, "buffer %d deleted\n", vb->index);
>> + kfree(vb);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(vb2_core_delete_buf);
> This is duplicating what already happens in __vb2_free_mem and __vb2_queue_free.
>
> That code needs to be refactored.
>
> What you want is a __vb2_delete_buffers(struct vb2_queue *q, unsigned int index, unsigned int buffers)
> function that is called with mmap_lock held and that deletes buffers in the range 'index'
> to 'index + count - 1'. Buffers may already be deleted.
>
> __vb2_free_mem does almost do all of that already.
>
> Then this new function can be called from __vb2_queue_free() and you can make
> a vb2_core_delete_bufs() function that takes the lock and calls __vb2_delete_buffers.
>
> Another note: currently __vb2_queue_free checks if any of the buffers had unbalanced
> operations. That check needs to be moved to __vb2_delete_buffers as well otherwise
> that would never be reported when using DELETE_BUFS.
Loops in __vb2_queue_free() and __vb2_free_mem() try to delete buffers at the end of the
queue, I could just modify these functions prototype and loops to start from a given index.
That should do the job but have impact on create_bufs (see below)
>
>> +
>> /*
>> * 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 8ba658ad9891..d0098f58a65c 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> @@ -385,7 +385,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
>>
>> vb = vb2_get_buffer(q, b->index);
>> if (!vb) {
>> - dprintk(q, 1, "%s: buffer is NULL\n", opname);
>> + dprintk(q, 1, "%s: buffer %u was deleted\n", opname, b->index);
>> return -EINVAL;
>> }
>>
>> @@ -757,6 +757,42 @@ int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
>> }
>> EXPORT_SYMBOL_GPL(vb2_prepare_buf);
>>
>> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d)
>> +{
>> + struct vb2_buffer *vb;
>> + unsigned int index;
>> + int ret = 0;
>> +
> Add:
>
> if (!d->count)
> return 0;
>
> (possibly also check if !d->index)
>
>> + if (d->index > q->num_buffers ||
>> should be >= here.
>> + d->count > q->num_buffers ||
>> + (d->index + d->count) > q->num_buffers) {
>> + return -EINVAL;
>> + }
> Once we can delete buffers, how does that change the meaning of num_buffers?
> Isn't this really max_buffer_index or something similar? But we probably also
> still need to keep track of the actual number of buffers.
>
> And create_bufs still allocated buffers from the last index onwards, it does
> not attempt to reuse indices of previously deleted buffers.
Reuse previous indices require to be sure that a range of index is free because
create_bufs returns, in index parameter, the starting buffer index.
I will add a function to find the first available range and use it in vb2_create_bufs()
to change how create->index is set.
Hans, sound good for you ?
>
> There are a lot of drivers that use num_buffers, they will have to be audited.
>
> This needs a lot more thought.
>
>> +
>> + for (index = d->index; index < d->index + d->count; index++) {
>> + vb = vb2_get_buffer(q, index);
>> + if (!vb) {
>> + dprintk(q, 1, "can't find the requested buffer\n");
>> + ret = -EINVAL;
>> + goto error;
>> + }
>> + if (vb->state != VB2_BUF_STATE_DEQUEUED) {
>> + dprintk(q, 1, "can't delete non dequeued buffer index %d\n", vb->index);
>> + ret = -EINVAL;
>> + goto error;
>> + }
> These checks have to take place first, then, if all is OK, you call vb2_core_delete_bufs.
>
> Actually, thinking this over, I would move all these checks to vb2_core_delete_bufs.
>
> It can all be put under the mmap_lock mutex to ensure nobody is messing around
> with the queue while this takes place.
>
> Note that when vb2_core_reqbufs() is called with count=0, then if it sees that
> a buffer is still in use (mmaped), it will log a debug message that the buffers
> are orphaned. We should keep that, I believe.
>
>> +
>> + ret = vb2_core_delete_buf(q, vb);
>> + if (ret)
>> + break;
>> + }
>> +
>> +error:
>> + d->index = index;
> I wouldn't do this. I don't think this is useful.
>
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(vb2_delete_bufs);
>> +
>> int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>> {
>> unsigned requested_planes = 1;
>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
>> index f81279492682..215654fd6581 100644
>> --- a/drivers/media/v4l2-core/v4l2-dev.c
>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
>> @@ -720,6 +720,7 @@ 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);
>> + SET_VALID_IOCTL(ops, VIDIOC_DELETE_BUFS, vidioc_delete_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 f4d9d6279094..aac3a0ea0126 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -489,6 +489,13 @@ static void v4l_print_create_buffers(const void *arg, bool write_only)
>> v4l_print_format(&p->format, write_only);
>> }
>>
>> +static void v4l_print_delete_buffers(const void *arg, bool write_only)
>> +{
>> + const struct v4l2_delete_buffers *p = arg;
>> +
>> + pr_cont("index=%d, count=%d\n", p->index, p->count);
> Use %u since both args are unsigned.
>
>> +}
>> +
>> static void v4l_print_streamparm(const void *arg, bool write_only)
>> {
>> const struct v4l2_streamparm *p = arg;
>> @@ -2160,6 +2167,15 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
>> return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
>> }
>>
>> +static int v4l_delete_bufs(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + struct v4l2_delete_buffers *delete = arg;
>> + int ret = check_fmt(file, delete->type);
>> +
>> + return ret ? ret : ops->vidioc_delete_bufs(file, fh, delete);
>> +}
>> +
>> static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
>> struct file *file, void *fh, void *arg)
>> {
>> @@ -2909,6 +2925,7 @@ 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_DELETE_BUFS, v4l_delete_bufs, v4l_print_delete_buffers, INFO_FL_PRIO | INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_delete_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..55afbde54211 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_delete_bufs: pointer to the function that implements
>> + * :ref:`VIDIOC_DELETE_BUFS <vidioc_delete_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_delete_bufs)(struct file *file, void *fh,
>> + struct v4l2_delete_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 97153c69583f..e2c5ff31efd0 100644
>> --- a/include/media/videobuf2-core.h
>> +++ b/include/media/videobuf2-core.h
>> @@ -843,6 +843,15 @@ 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_delete_buf() -
>> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
>> + * @vb: pointer to struct &vb2_buffer.
>> + *
>> + * Return: returns zero on success; an error code otherwise.
>> + */
>> +int vb2_core_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb);
>> +
>> /**
>> * vb2_core_qbuf() - Queue a buffer from userspace
>> *
>> diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
>> index 5a845887850b..2ef68fdf388f 100644
>> --- a/include/media/videobuf2-v4l2.h
>> +++ b/include/media/videobuf2-v4l2.h
>> @@ -118,6 +118,17 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
>> */
>> int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
>> struct v4l2_buffer *b);
>> +/**
>> + * vb2_delete_bufs() - Delete buffers from the queue
>> + *
>> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
>> + * @d: delete parameter, passed from userspace to
>> + * &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver
>> + *
>> + * The return values from this function are intended to be directly returned
>> + * from &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver.
>> + */
>> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d);
> I'm missing the vb2_ioctl_delete_bufs function with a call to vb2_queue_is_busy().
>
>>
>> /**
>> * vb2_qbuf() - Queue a buffer from userspace
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 78260e5d9985..9cc7f570d995 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -2616,6 +2616,20 @@ struct v4l2_create_buffers {
>> __u32 reserved[6];
>> };
>>
>> +/**
>> + * struct v4l2_delete_buffers - VIDIOC_DELETE_BUFS argument
>> + * @index: the first buffer to be deleted
>> + * @count: number of buffers to delete
>> + * @type: enum v4l2_buf_type
>> + * @reserved: future extensions
>> + */
>> +struct v4l2_delete_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
>> *
>> @@ -2715,6 +2729,8 @@ 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_DELETE_BUFS _IOWR('V', 104, struct v4l2_delete_buffers)
>> +
>>
>> /* Reminder: when adding new ioctls please add support for them to
>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
> You need much more extensive compliance checks for this, esp. mixing
> create_bufs and delete_bufs. And test it with the test-media test script.
>
> Regards,
>
> Hans
>
Hi Benjamin,
On 05/09/2023 16:28, Benjamin Gaignard wrote:
>
> Le 05/09/2023 à 10:17, Hans Verkuil a écrit :
>> On 01/09/2023 14:44, Benjamin Gaignard wrote:
>>> VIDIOC_DELETE_BUFS ioctl allows to delete buffers from a queue.
>>> The number of buffers to delete in given by count field of
>>> struct v4l2_delete_buffers and the range start at the index
>>> specified in the same structure.
>>>
>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>> ---
>>> v6:
>>> - Add lock in vb2_core_delete_buf()
>>> - Fix typo and comments
>>> - Add flags in VIDIOC_DELETE_BUFS decalaration
>>>
>>> .../userspace-api/media/v4l/user-func.rst | 1 +
>>> .../media/v4l/vidioc-delete-bufs.rst | 73 +++++++++++++++++++
>>> .../media/common/videobuf2/videobuf2-core.c | 24 ++++++
>>> .../media/common/videobuf2/videobuf2-v4l2.c | 38 +++++++++-
>>> drivers/media/v4l2-core/v4l2-dev.c | 1 +
>>> drivers/media/v4l2-core/v4l2-ioctl.c | 17 +++++
>>> include/media/v4l2-ioctl.h | 4 +
>>> include/media/videobuf2-core.h | 9 +++
>>> include/media/videobuf2-v4l2.h | 11 +++
>>> include/uapi/linux/videodev2.h | 16 ++++
>>> 10 files changed, 193 insertions(+), 1 deletion(-)
>>> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>>>
>>> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
>>> index 15ff0bf7bbe6..3fd567695477 100644
>>> --- a/Documentation/userspace-api/media/v4l/user-func.rst
>>> +++ b/Documentation/userspace-api/media/v4l/user-func.rst
>>> @@ -17,6 +17,7 @@ Function Reference
>>> vidioc-dbg-g-chip-info
>>> vidioc-dbg-g-register
>>> vidioc-decoder-cmd
>>> + vidioc-delete-bufs
>>> vidioc-dqevent
>>> vidioc-dv-timings-cap
>>> vidioc-encoder-cmd
>>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>>> new file mode 100644
>>> index 000000000000..a55fe6331fc8
>>> --- /dev/null
>>> +++ b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst
>>> @@ -0,0 +1,73 @@
>>> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
>>> +.. c:namespace:: V4L
>>> +
>>> +.. _VIDIOC_DELETE_BUFS:
>>> +
>>> +************************
>>> +ioctl VIDIOC_DELETE_BUFS
>>> +************************
>>> +
>>> +Name
>>> +====
>>> +
>>> +VIDIOC_DELETE_BUFS - Deletes buffers from a queue
>>> +
>>> +Synopsis
>>> +========
>>> +
>>> +.. c:macro:: VIDIOC_DELETE_BUFs
>>> +
>>> +``int ioctl(int fd, VIDIOC_DELETE_BUFs, struct v4l2_delete_buffers *argp)``
>>> +
>>> +Arguments
>>> +=========
>>> +
>>> +``fd``
>>> + File descriptor returned by :c:func:`open()`.
>>> +
>>> +``argp``
>>> + Pointer to struct :c:type:`v4l2_delete_buffers`.
>>> +
>>> +Description
>>> +===========
>>> +
>>> +Applications can optionally call the :ref:`VIDIOC_DELETE_BUFS` ioctl to
>>> +delete buffers from a queue.
>>> +
>>> +.. c:type:: v4l2_delete_buffers
>>> +
>>> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
>>> +
>>> +.. flat-table:: struct v4l2_delete_buffers
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 1 2
>>> +
>>> + * - __u32
>>> + - ``index``
>>> + - The starting buffer index to delete.
>>> + * - __u32
>>> + - ``count``
>>> + - The number of buffers to be deleted.
>> That's not quite correct. This function will delete the buffers with indices
>> index until index+count-1. And indices in that range have to be valid buffers,
>> i.e. you can't have already deleted buffers in that range.
>>
>> Or should we allow that? It is a fair question.
>>
>> All buffers also have to be in the DEQUEUED state.
>>
>> The text above suggests that given the following valid indices:
>>
>> 0, 1, 3, 4 (so the buffer with index 2 was already deleted)
>>
>> deleting 2 buffers from index 1 would delete buffers 1, 3. When in
>> fact it will attempt to delete buffers 1 and 2.
>>
>> Also document explicitly that calling this with count=0 (and perhaps
>> index=0 as well?) can be used to check if this ioctl is supported.
>
> I will do that.
>
>>
>>> + * - __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.
>> What should happen if you delete ALL buffers with this call? I.e., the
>> equivalent to REQBUFS with count=0.
>>
>> Thinking about this the main difference is that DELETE_BUFS can only delete
>> dequeued buffers and it does not stop streaming if all buffers are deleted.
>>
>> So REQBUFS with count=0 (or a STREAMOFF) is still needed to officially stop
>> streaming and cancel the queue.
>>
>> Basically REQBUFS with count=0 is almost the equivalent of calling STREAMOFF followed
>> by DELETE_BUFS for all buffers. Almost, but not quite: REQBUFS(0) also reports
>> if the queue is unbalanced, and it sets q->num_buffers to 0. And in vb2_ioctl_reqbufs
>> it will set vdev->queue->owner to NULL.
>>
>> I am inclined to do the same if DELETE_BUFS deletes all buffers.
>
> Unlike REQBUFS DELETE_BUFS can delete buffers while streaming so for me the ownership
> should not change even if there is no more dequeued buffers.
> For REQBUFS with count=0 means that the going stream is stopped so we can delete all the buffers
> while DELETE_BUFS usage is to delete buffers while keeping the stream alive.
I'm undecided on this. It's something we can decide later.
>
>>
>>> +
>>> +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.
>>> +
>>> +EBUSY
>>> + File I/O is in progress.
>>> +
>>> +EINVAL
>>> + The buffer ``index`` doesn't exist in the queue.
>>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>>> index dc7f6b59d237..9edb2a1e95fc 100644
>>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>>> @@ -1633,6 +1633,30 @@ 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_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb)
>>> +{
>>> + mutex_lock(&q->mmap_lock);
>>> + if (vb->planes[0].mem_priv)
>>> + call_void_vb_qop(vb, buf_cleanup, vb);
>>> +
>>> + /* Free MMAP buffers or release USERPTR buffers */
>>> + if (q->memory == VB2_MEMORY_MMAP)
>>> + __vb2_buf_mem_free(vb);
>>> + else if (q->memory == VB2_MEMORY_DMABUF)
>>> + __vb2_buf_dmabuf_put(vb);
>>> + else
>>> + __vb2_buf_userptr_put(vb);
>>> +
>>> + vb2_queue_remove_buffer(q, vb);
>>> + mutex_unlock(&q->mmap_lock);
>>> +
>>> + dprintk(q, 2, "buffer %d deleted\n", vb->index);
>>> + kfree(vb);
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(vb2_core_delete_buf);
>> This is duplicating what already happens in __vb2_free_mem and __vb2_queue_free.
>>
>> That code needs to be refactored.
>>
>> What you want is a __vb2_delete_buffers(struct vb2_queue *q, unsigned int index, unsigned int buffers)
>> function that is called with mmap_lock held and that deletes buffers in the range 'index'
>> to 'index + count - 1'. Buffers may already be deleted.
>>
>> __vb2_free_mem does almost do all of that already.
>>
>> Then this new function can be called from __vb2_queue_free() and you can make
>> a vb2_core_delete_bufs() function that takes the lock and calls __vb2_delete_buffers.
>>
>> Another note: currently __vb2_queue_free checks if any of the buffers had unbalanced
>> operations. That check needs to be moved to __vb2_delete_buffers as well otherwise
>> that would never be reported when using DELETE_BUFS.
>
> Loops in __vb2_queue_free() and __vb2_free_mem() try to delete buffers at the end of the
> queue, I could just modify these functions prototype and loops to start from a given index.
> That should do the job but have impact on create_bufs (see below)
>
>>
>>> +
>>> /*
>>> * 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 8ba658ad9891..d0098f58a65c 100644
>>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> @@ -385,7 +385,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
>>> vb = vb2_get_buffer(q, b->index);
>>> if (!vb) {
>>> - dprintk(q, 1, "%s: buffer is NULL\n", opname);
>>> + dprintk(q, 1, "%s: buffer %u was deleted\n", opname, b->index);
>>> return -EINVAL;
>>> }
>>> @@ -757,6 +757,42 @@ int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
>>> }
>>> EXPORT_SYMBOL_GPL(vb2_prepare_buf);
>>> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d)
>>> +{
>>> + struct vb2_buffer *vb;
>>> + unsigned int index;
>>> + int ret = 0;
>>> +
>> Add:
>>
>> if (!d->count)
>> return 0;
>>
>> (possibly also check if !d->index)
>>
>>> + if (d->index > q->num_buffers ||
>>> should be >= here.
>>> + d->count > q->num_buffers ||
>>> + (d->index + d->count) > q->num_buffers) {
>>> + return -EINVAL;
>>> + }
>> Once we can delete buffers, how does that change the meaning of num_buffers?
>> Isn't this really max_buffer_index or something similar? But we probably also
>> still need to keep track of the actual number of buffers.
>>
>> And create_bufs still allocated buffers from the last index onwards, it does
>> not attempt to reuse indices of previously deleted buffers.
>
> Reuse previous indices require to be sure that a range of index is free because
> create_bufs returns, in index parameter, the starting buffer index.
> I will add a function to find the first available range and use it in vb2_create_bufs()
> to change how create->index is set.
> Hans, sound good for you ?
That's what I had in mind. It is an option to keep a bitmap to keep track
of which buffer indices are in use. You could use bitmap_find_next_zero_area
to find the free range.
Just an option.
>
>>
>> There are a lot of drivers that use num_buffers, they will have to be audited.
>>
>> This needs a lot more thought.
>>
>>> +
>>> + for (index = d->index; index < d->index + d->count; index++) {
>>> + vb = vb2_get_buffer(q, index);
>>> + if (!vb) {
>>> + dprintk(q, 1, "can't find the requested buffer\n");
>>> + ret = -EINVAL;
>>> + goto error;
>>> + }
>>> + if (vb->state != VB2_BUF_STATE_DEQUEUED) {
>>> + dprintk(q, 1, "can't delete non dequeued buffer index %d\n", vb->index);
>>> + ret = -EINVAL;
>>> + goto error;
>>> + }
>> These checks have to take place first, then, if all is OK, you call vb2_core_delete_bufs.
>>
>> Actually, thinking this over, I would move all these checks to vb2_core_delete_bufs.
>>
>> It can all be put under the mmap_lock mutex to ensure nobody is messing around
>> with the queue while this takes place.
>>
>> Note that when vb2_core_reqbufs() is called with count=0, then if it sees that
>> a buffer is still in use (mmaped), it will log a debug message that the buffers
>> are orphaned. We should keep that, I believe.
>>
>>> +
>>> + ret = vb2_core_delete_buf(q, vb);
>>> + if (ret)
>>> + break;
>>> + }
>>> +
>>> +error:
>>> + d->index = index;
>> I wouldn't do this. I don't think this is useful.
>>
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(vb2_delete_bufs);
>>> +
>>> int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>>> {
>>> unsigned requested_planes = 1;
>>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
>>> index f81279492682..215654fd6581 100644
>>> --- a/drivers/media/v4l2-core/v4l2-dev.c
>>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
>>> @@ -720,6 +720,7 @@ 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);
>>> + SET_VALID_IOCTL(ops, VIDIOC_DELETE_BUFS, vidioc_delete_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 f4d9d6279094..aac3a0ea0126 100644
>>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> @@ -489,6 +489,13 @@ static void v4l_print_create_buffers(const void *arg, bool write_only)
>>> v4l_print_format(&p->format, write_only);
>>> }
>>> +static void v4l_print_delete_buffers(const void *arg, bool write_only)
>>> +{
>>> + const struct v4l2_delete_buffers *p = arg;
>>> +
>>> + pr_cont("index=%d, count=%d\n", p->index, p->count);
>> Use %u since both args are unsigned.
>>
>>> +}
>>> +
>>> static void v4l_print_streamparm(const void *arg, bool write_only)
>>> {
>>> const struct v4l2_streamparm *p = arg;
>>> @@ -2160,6 +2167,15 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
>>> return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
>>> }
>>> +static int v4l_delete_bufs(const struct v4l2_ioctl_ops *ops,
>>> + struct file *file, void *fh, void *arg)
>>> +{
>>> + struct v4l2_delete_buffers *delete = arg;
>>> + int ret = check_fmt(file, delete->type);
>>> +
>>> + return ret ? ret : ops->vidioc_delete_bufs(file, fh, delete);
>>> +}
>>> +
>>> static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
>>> struct file *file, void *fh, void *arg)
>>> {
>>> @@ -2909,6 +2925,7 @@ 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_DELETE_BUFS, v4l_delete_bufs, v4l_print_delete_buffers, INFO_FL_PRIO | INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_delete_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..55afbde54211 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_delete_bufs: pointer to the function that implements
>>> + * :ref:`VIDIOC_DELETE_BUFS <vidioc_delete_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_delete_bufs)(struct file *file, void *fh,
>>> + struct v4l2_delete_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 97153c69583f..e2c5ff31efd0 100644
>>> --- a/include/media/videobuf2-core.h
>>> +++ b/include/media/videobuf2-core.h
>>> @@ -843,6 +843,15 @@ 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_delete_buf() -
>>> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
>>> + * @vb: pointer to struct &vb2_buffer.
>>> + *
>>> + * Return: returns zero on success; an error code otherwise.
>>> + */
>>> +int vb2_core_delete_buf(struct vb2_queue *q, struct vb2_buffer *vb);
>>> +
>>> /**
>>> * vb2_core_qbuf() - Queue a buffer from userspace
>>> *
>>> diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
>>> index 5a845887850b..2ef68fdf388f 100644
>>> --- a/include/media/videobuf2-v4l2.h
>>> +++ b/include/media/videobuf2-v4l2.h
>>> @@ -118,6 +118,17 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
>>> */
>>> int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
>>> struct v4l2_buffer *b);
>>> +/**
>>> + * vb2_delete_bufs() - Delete buffers from the queue
>>> + *
>>> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
>>> + * @d: delete parameter, passed from userspace to
>>> + * &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver
>>> + *
>>> + * The return values from this function are intended to be directly returned
>>> + * from &v4l2_ioctl_ops->vidioc_delete_bufs handler in driver.
>>> + */
>>> +int vb2_delete_bufs(struct vb2_queue *q, struct v4l2_delete_buffers *d);
>> I'm missing the vb2_ioctl_delete_bufs function with a call to vb2_queue_is_busy().
>>
>>> /**
>>> * vb2_qbuf() - Queue a buffer from userspace
>>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>>> index 78260e5d9985..9cc7f570d995 100644
>>> --- a/include/uapi/linux/videodev2.h
>>> +++ b/include/uapi/linux/videodev2.h
>>> @@ -2616,6 +2616,20 @@ struct v4l2_create_buffers {
>>> __u32 reserved[6];
>>> };
>>> +/**
>>> + * struct v4l2_delete_buffers - VIDIOC_DELETE_BUFS argument
>>> + * @index: the first buffer to be deleted
>>> + * @count: number of buffers to delete
>>> + * @type: enum v4l2_buf_type
>>> + * @reserved: future extensions
>>> + */
>>> +struct v4l2_delete_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
>>> *
>>> @@ -2715,6 +2729,8 @@ 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_DELETE_BUFS _IOWR('V', 104, struct v4l2_delete_buffers)
>>> +
>>> /* Reminder: when adding new ioctls please add support for them to
>>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
>> You need much more extensive compliance checks for this, esp. mixing
>> create_bufs and delete_bufs. And test it with the test-media test script.
>>
>> Regards,
>>
>> Hans
>>
Regards,
Hans
On 05/09/2023 10:17, Hans Verkuil wrote: > > You need much more extensive compliance checks for this, esp. mixing > create_bufs and delete_bufs. And test it with the test-media test script. This also means that you need to add patches adding delete_bufs support to vivid, vim2m, vimc, vicodec, visl. That allows test-media together with v4l2-compliance to do a good job of regression testing this new ioctl. Regards, Hans
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