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From:   Benjamin Gaignard <benjamin.gaignard@collabora.com>
To:     mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com,
        ming.qian@nxp.com, ezequiel@vanguardiasur.com.ar,
        p.zabel@pengutronix.de, gregkh@linuxfoundation.org,
        hverkuil-cisco@xs4all.nl, nicolas.dufresne@collabora.com
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev,
        kernel@collabora.com,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>
Subject: [PATCH v3 10/11] media: v4l2: Add DELETE_BUF ioctl
Date:   Thu, 22 Jun 2023 15:13:48 +0200
Message-Id: <20230622131349.144160-11-benjamin.gaignard@collabora.com>
In-Reply-To: <20230622131349.144160-1-benjamin.gaignard@collabora.com>
References: <20230622131349.144160-1-benjamin.gaignard@collabora.com>
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VIDIOC_DELETE_BUF ioctl allows to delete a buffer from a queue.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
 .../userspace-api/media/v4l/user-func.rst     |  1 +
 .../media/v4l/vidioc-delete-buf.rst           | 51 +++++++++++++++++++
 .../media/common/videobuf2/videobuf2-core.c   | 33 ++++++++++++
 .../media/common/videobuf2/videobuf2-v4l2.c   |  6 +++
 drivers/media/v4l2-core/v4l2-dev.c            |  1 +
 drivers/media/v4l2-core/v4l2-ioctl.c          | 10 ++++
 include/media/v4l2-ioctl.h                    |  4 ++
 include/media/videobuf2-core.h                |  9 ++++
 include/media/videobuf2-v4l2.h                | 11 ++++
 include/uapi/linux/videodev2.h                |  2 +
 10 files changed, 128 insertions(+)
 create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-buf.rst

diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
index 15ff0bf7bbe6..8c74016e12fd 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-buf
     vidioc-dqevent
     vidioc-dv-timings-cap
     vidioc-encoder-cmd
diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-buf.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-buf.rst
new file mode 100644
index 000000000000..0e7ce58f91bc
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/vidioc-delete-buf.rst
@@ -0,0 +1,51 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: V4L
+
+.. _VIDIOC_DELETE_BUF:
+
+************************
+ioctl VIDIOC_DELETE_BUF
+************************
+
+Name
+====
+
+VIDIOC_DELETE_BUF - Delete a buffer from a queue
+
+Synopsis
+========
+
+.. c:macro:: VIDIOC_DELETE_BUF
+
+``int ioctl(int fd, VIDIOC_DELETE_BUF, struct v4l2_buffer *argp)``
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :c:func:`open()`.
+
+``argp``
+    Pointer to struct :c:type:`v4l2_buffer`.
+
+Description
+===========
+
+Applications can optionally call the :ref:`VIDIOC_DELETE_BUF` ioctl to
+delete a buffer from a queue.
+
+The struct :c:type:`v4l2_buffer` structure is specified in
+:ref:`buffer`.
+
+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 899783f67580..aa546c972c3d 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -1637,6 +1637,39 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
 }
 EXPORT_SYMBOL_GPL(vb2_core_prepare_buf);
 
+int vb2_core_delete_buf(struct vb2_queue *q, unsigned int index)
+{
+	struct vb2_buffer *vb;
+
+	vb = vb2_get_buffer(q, index);
+	if (!vb) {
+		dprintk(q, 1, "invalid buffer index %d\n", index);
+		return -EINVAL;
+	}
+
+	if (vb->state != VB2_BUF_STATE_DEQUEUED) {
+		dprintk(q, 1, "can't delete non dequeued buffer index %d\n", index);
+		return -EINVAL;
+	}
+
+	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);
+	kfree(vb);
+
+	dprintk(q, 2, "buffer %d deleted\n", index);
+	return 0;
+}
+
 /*
  * 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 724135d41f7f..cea666c17b41 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -751,6 +751,12 @@ int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
 }
 EXPORT_SYMBOL_GPL(vb2_prepare_buf);
 
+int vb2_delete_buf(struct vb2_queue *q, struct v4l2_buffer *b)
+{
+	return vb2_core_delete_buf(q, b->index);
+}
+EXPORT_SYMBOL_GPL(vb2_delete_buf);
+
 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..80ace2e1e932 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_BUF, vidioc_delete_buf);
 	}
 
 	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 a858acea6547..1c737279d3ef 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2156,6 +2156,15 @@ 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_buf(const struct v4l2_ioctl_ops *ops,
+			  struct file *file, void *fh, void *arg)
+{
+	struct v4l2_buffer *b = arg;
+	int ret = check_fmt(file, b->type);
+
+	return ret ? ret : ops->vidioc_delete_buf(file, fh, b);
+}
+
 static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
@@ -2905,6 +2914,7 @@ 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_BUF, v4l_delete_buf, v4l_print_buffer, INFO_FL_QUEUE),
 };
 #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index edb733f21604..2f232ed884c7 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_buf: pointer to the function that implements
+ *	:ref:`VIDIOC_DELETE_BUF <vidioc_delete_buf>` 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_buf)(struct file *file, void *fh,
+				 struct v4l2_buffer *b);
 
 	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 080b783d608d..0f9e68f76b77 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -840,6 +840,15 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
  */
 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
 
+/**
+ * vb2_core_delete_buf() -
+ * @q: pointer to &struct vb2_queue with videobuf2 queue.
+ * @index:	id number of the buffer.
+ *
+ *  Return: returns zero on success; an error code otherwise.
+ */
+int vb2_core_delete_buf(struct vb2_queue *q, unsigned int index);
+
 /**
  * vb2_core_qbuf() - Queue a buffer from userspace
  *
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
index 88a7a565170e..3beeb4c735f0 100644
--- a/include/media/videobuf2-v4l2.h
+++ b/include/media/videobuf2-v4l2.h
@@ -114,6 +114,17 @@ 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_buf() - Delete the buffer from the queue
+ *
+ * @q:		pointer to &struct vb2_queue with videobuf2 queue.
+ * @b:		buffer structure passed from userspace to
+ *		&v4l2_ioctl_ops->vidioc_delete_buf handler in driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from &v4l2_ioctl_ops->vidioc_delete_buf handler in driver.
+ */
+int vb2_delete_buf(struct vb2_queue *q, struct v4l2_buffer *b);
 
 /**
  * vb2_qbuf() - Queue a buffer from userspace
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index aee75eb9e686..31bba1915642 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2702,6 +2702,8 @@ 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_BUF	_IOWR('V', 104, struct v4l2_buffer)
+
 
 /* Reminder: when adding new ioctls please add support for them to
    drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
-- 
2.39.2