[PATCHv2 0/3] vb2: add buf_out_validate callback

[PATCHv2 0/3] vb2: add buf_out_validate callback

[hverkuil-cisco]

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Adding the request API uncovered a pre-existing problem with
validating output buffers.

The problem is that for output buffers the driver has to validate
the 'field' field of struct v4l2_buffer. This is critical when
encoding or deinterlacing interlaced video.

Drivers always did this in the buf_prepare callback, but that is
not called from VIDIOC_QBUF in two situations: when queueing a
buffer to a request and if VIDIOC_PREPARE_BUF has been called
earlier for that buffer.

As a result of this the 'field' value is not validated.

While the first case (queueing a buffer to a request) is request
API specific, the second case (VIDIOC_PREPARE_BUF has been called
earlier for that buffer) was always wrong.

This patch series adds a new buf_out_validate callback to validate
the output buffer at QBUF time.

Note that PREPARE_BUF doesn't need to validate the field: it just
locks the buffer memory and doesn't need nor want to know about
how this buffer is actually going to be used. It's the QBUF ioctl
that determines this.

This issue was found by v4l2-compliance since vivid failed to replace
V4L2_FIELD_ANY by a proper field value when testing the vivid video
output in combination with requests.

There never was a test before for the PREPARE_BUF/QBUF case, so even
though this bug has been present for quite some time, it was never
noticed. This test has now been added to v4l2-compliance as well.

Regards,

	Hans

Changes since v1:

- Renamed buf_validate to buf_out_validate since this is output
  specific.
- Clarify in the commit log of the first patch that this isn't
  request API specific, but fixes a long standing problem that
  just wasn't noticed until now.

Hans Verkuil (3):
  vb2: add buf_out_validate callback
  vim2m: add buf_out_validate callback
  vivid: add buf_out_validate callback

 .../media/common/videobuf2/videobuf2-core.c   | 14 ++++++++---
 drivers/media/platform/vim2m.c                | 16 ++++++++++---
 drivers/media/platform/vivid/vivid-vid-out.c  | 23 +++++++++++++------
 include/media/videobuf2-core.h                |  5 ++++
 4 files changed, 45 insertions(+), 13 deletions(-)

-- 
2.19.2

[PATCHv2 1/3] vb2: add buf_out_validate callback

[hverkuil-cisco]

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Adding the request API uncovered a pre-existing problem with
validating output buffers.

The problem is that for output buffers the driver has to validate
the 'field' field of struct v4l2_buffer. This is critical when
encoding or deinterlacing interlaced video.

Drivers always did this in the buf_prepare callback, but that is
not called from VIDIOC_QBUF in two situations: when queueing a
buffer to a request and if VIDIOC_PREPARE_BUF has been called
earlier for that buffer.

As a result of this the 'field' value is not validated.

While the first case (queueing a buffer to a request) is request
API specific, the second case (VIDIOC_PREPARE_BUF has been called
earlier for that buffer) was always wrong.

This patch adds a new buf_out_validate callback to validate the
output buffer at QBUF time.

Note that PREPARE_BUF doesn't need to validate this: it just
locks the buffer memory and doesn't need nor want to know about
how this buffer is actually going to be used. It's the QBUF ioctl
that determines this.

This issue was found by v4l2-compliance since it failed to replace
V4L2_FIELD_ANY by a proper field value when testing the vivid video
output in combination with requests.

There never was a test before for the PREPARE_BUF/QBUF case, so even
though this bug has been present for quite some time, it was never
noticed.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/common/videobuf2/videobuf2-core.c | 14 +++++++++++---
 include/media/videobuf2-core.h                  |  5 +++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 70e8c3366f9c..653e933db854 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -499,9 +499,9 @@ static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 			pr_info("     buf_init: %u buf_cleanup: %u buf_prepare: %u buf_finish: %u\n",
 				vb->cnt_buf_init, vb->cnt_buf_cleanup,
 				vb->cnt_buf_prepare, vb->cnt_buf_finish);
-			pr_info("     buf_queue: %u buf_done: %u buf_request_complete: %u\n",
-				vb->cnt_buf_queue, vb->cnt_buf_done,
-				vb->cnt_buf_request_complete);
+			pr_info("     buf_out_validate: %u buf_queue: %u buf_done: %u buf_request_complete: %u\n",
+				vb->cnt_buf_out_validate, vb->cnt_buf_queue,
+				vb->cnt_buf_done, vb->cnt_buf_request_complete);
 			pr_info("     alloc: %u put: %u prepare: %u finish: %u mmap: %u\n",
 				vb->cnt_mem_alloc, vb->cnt_mem_put,
 				vb->cnt_mem_prepare, vb->cnt_mem_finish,
@@ -1510,6 +1510,14 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
 		return -EBUSY;
 	}
 
+	if (q->is_output) {
+		ret = call_vb_qop(vb, buf_out_validate, vb);
+		if (ret) {
+			dprintk(1, "buffer validation failed\n");
+			return ret;
+		}
+	}
+
 	if (req) {
 		int ret;
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 4a737b2c610b..91f1e66aacc6 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -296,6 +296,7 @@ struct vb2_buffer {
 	u32		cnt_mem_num_users;
 	u32		cnt_mem_mmap;
 
+	u32		cnt_buf_out_validate;
 	u32		cnt_buf_init;
 	u32		cnt_buf_prepare;
 	u32		cnt_buf_finish;
@@ -342,6 +343,9 @@ struct vb2_buffer {
  * @wait_finish:	reacquire all locks released in the previous callback;
  *			required to continue operation after sleeping while
  *			waiting for a new buffer to arrive.
+ * @buf_out_validate:	called every time the output buffer is queued from
+ *			userspace; drivers can use this to validate
+ *			userspace-provided information; optional.
  * @buf_init:		called once after allocating a buffer (in MMAP case)
  *			or after acquiring a new USERPTR buffer; drivers may
  *			perform additional buffer-related initialization;
@@ -409,6 +413,7 @@ struct vb2_ops {
 	void (*wait_prepare)(struct vb2_queue *q);
 	void (*wait_finish)(struct vb2_queue *q);
 
+	int (*buf_out_validate)(struct vb2_buffer *vb);
 	int (*buf_init)(struct vb2_buffer *vb);
 	int (*buf_prepare)(struct vb2_buffer *vb);
 	void (*buf_finish)(struct vb2_buffer *vb);
-- 
2.19.2

[PATCHv2 2/3] vim2m: add buf_out_validate callback

[hverkuil-cisco]

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Split off the field validation from buf_prepare into a new
buf_out_validate function. Field validation for output buffers should
be done there since buf_prepare is not guaranteed to be called at
QBUF time.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/platform/vim2m.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/vim2m.c b/drivers/media/platform/vim2m.c
index d01821a6906a..4a16b7a6b69a 100644
--- a/drivers/media/platform/vim2m.c
+++ b/drivers/media/platform/vim2m.c
@@ -753,15 +753,13 @@ static int vim2m_queue_setup(struct vb2_queue *vq,
 	return 0;
 }
 
-static int vim2m_buf_prepare(struct vb2_buffer *vb)
+static int vim2m_buf_out_validate(struct vb2_buffer *vb)
 {
 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 	struct vim2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
-	struct vim2m_q_data *q_data;
 
 	dprintk(ctx->dev, "type: %d\n", vb->vb2_queue->type);
 
-	q_data = get_q_data(ctx, vb->vb2_queue->type);
 	if (V4L2_TYPE_IS_OUTPUT(vb->vb2_queue->type)) {
 		if (vbuf->field == V4L2_FIELD_ANY)
 			vbuf->field = V4L2_FIELD_NONE;
@@ -772,6 +770,17 @@ static int vim2m_buf_prepare(struct vb2_buffer *vb)
 		}
 	}
 
+	return 0;
+}
+
+static int vim2m_buf_prepare(struct vb2_buffer *vb)
+{
+	struct vim2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	struct vim2m_q_data *q_data;
+
+	dprintk(ctx->dev, "type: %d\n", vb->vb2_queue->type);
+
+	q_data = get_q_data(ctx, vb->vb2_queue->type);
 	if (vb2_plane_size(vb, 0) < q_data->sizeimage) {
 		dprintk(ctx->dev, "%s data will not fit into plane (%lu < %lu)\n",
 				__func__, vb2_plane_size(vb, 0), (long)q_data->sizeimage);
@@ -832,6 +841,7 @@ static void vim2m_buf_request_complete(struct vb2_buffer *vb)
 
 static const struct vb2_ops vim2m_qops = {
 	.queue_setup	 = vim2m_queue_setup,
+	.buf_out_validate	 = vim2m_buf_out_validate,
 	.buf_prepare	 = vim2m_buf_prepare,
 	.buf_queue	 = vim2m_buf_queue,
 	.start_streaming = vim2m_start_streaming,
-- 
2.19.2

[PATCHv3 2/3] vim2m: add buf_out_validate callback

[Hans Verkuil]

Split off the field validation from buf_prepare into a new
buf_out_validate function. Field validation for output buffers should
be done there since buf_prepare is not guaranteed to be called at
QBUF time.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
Changes since v2:
- drop test whether the queue is an output queue. This callback is only
  called for output queues, so this test is not needed anymore.
---
 drivers/media/platform/vim2m.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/media/platform/vim2m.c b/drivers/media/platform/vim2m.c
index 33397d4a1402..b2a6131469c4 100644
--- a/drivers/media/platform/vim2m.c
+++ b/drivers/media/platform/vim2m.c
@@ -743,25 +743,29 @@ static int vim2m_queue_setup(struct vb2_queue *vq,
 	return 0;
 }

-static int vim2m_buf_prepare(struct vb2_buffer *vb)
+static int vim2m_buf_out_validate(struct vb2_buffer *vb)
 {
 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 	struct vim2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+
+	if (vbuf->field == V4L2_FIELD_ANY)
+		vbuf->field = V4L2_FIELD_NONE;
+	if (vbuf->field != V4L2_FIELD_NONE) {
+		dprintk(ctx->dev, "%s field isn't supported\n", __func__);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int vim2m_buf_prepare(struct vb2_buffer *vb)
+{
+	struct vim2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
 	struct vim2m_q_data *q_data;

 	dprintk(ctx->dev, "type: %d\n", vb->vb2_queue->type);

 	q_data = get_q_data(ctx, vb->vb2_queue->type);
-	if (V4L2_TYPE_IS_OUTPUT(vb->vb2_queue->type)) {
-		if (vbuf->field == V4L2_FIELD_ANY)
-			vbuf->field = V4L2_FIELD_NONE;
-		if (vbuf->field != V4L2_FIELD_NONE) {
-			dprintk(ctx->dev, "%s field isn't supported\n",
-					__func__);
-			return -EINVAL;
-		}
-	}
-
 	if (vb2_plane_size(vb, 0) < q_data->sizeimage) {
 		dprintk(ctx->dev, "%s data will not fit into plane (%lu < %lu)\n",
 				__func__, vb2_plane_size(vb, 0), (long)q_data->sizeimage);
@@ -822,6 +826,7 @@ static void vim2m_buf_request_complete(struct vb2_buffer *vb)

 static const struct vb2_ops vim2m_qops = {
 	.queue_setup	 = vim2m_queue_setup,
+	.buf_out_validate	 = vim2m_buf_out_validate,
 	.buf_prepare	 = vim2m_buf_prepare,
 	.buf_queue	 = vim2m_buf_queue,
 	.start_streaming = vim2m_start_streaming,
-- 
2.20.1

[PATCHv2 3/3] vivid: add buf_out_validate callback

[hverkuil-cisco]

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Split off the field validation from buf_prepare into a new
buf_out_validate function. Field validation for output buffers should
be done there since buf_prepare is not guaranteed to be called at
QBUF time.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/platform/vivid/vivid-vid-out.c | 23 ++++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/vivid/vivid-vid-out.c b/drivers/media/platform/vivid/vivid-vid-out.c
index ea250aee2b2e..e45753a1adde 100644
--- a/drivers/media/platform/vivid/vivid-vid-out.c
+++ b/drivers/media/platform/vivid/vivid-vid-out.c
@@ -81,10 +81,24 @@ static int vid_out_queue_setup(struct vb2_queue *vq,
 	return 0;
 }
 
-static int vid_out_buf_prepare(struct vb2_buffer *vb)
+static int vid_out_buf_out_validate(struct vb2_buffer *vb)
 {
 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 	struct vivid_dev *dev = vb2_get_drv_priv(vb->vb2_queue);
+
+	dprintk(dev, 1, "%s\n", __func__);
+
+	if (dev->field_out != V4L2_FIELD_ALTERNATE)
+		vbuf->field = dev->field_out;
+	else if (vbuf->field != V4L2_FIELD_TOP &&
+		 vbuf->field != V4L2_FIELD_BOTTOM)
+		return -EINVAL;
+	return 0;
+}
+
+static int vid_out_buf_prepare(struct vb2_buffer *vb)
+{
+	struct vivid_dev *dev = vb2_get_drv_priv(vb->vb2_queue);
 	unsigned long size;
 	unsigned planes;
 	unsigned p;
@@ -105,12 +119,6 @@ static int vid_out_buf_prepare(struct vb2_buffer *vb)
 		return -EINVAL;
 	}
 
-	if (dev->field_out != V4L2_FIELD_ALTERNATE)
-		vbuf->field = dev->field_out;
-	else if (vbuf->field != V4L2_FIELD_TOP &&
-		 vbuf->field != V4L2_FIELD_BOTTOM)
-		return -EINVAL;
-
 	for (p = 0; p < planes; p++) {
 		size = dev->bytesperline_out[p] * dev->fmt_out_rect.height +
 			vb->planes[p].data_offset;
@@ -188,6 +196,7 @@ static void vid_out_buf_request_complete(struct vb2_buffer *vb)
 
 const struct vb2_ops vivid_vid_out_qops = {
 	.queue_setup		= vid_out_queue_setup,
+	.buf_out_validate		= vid_out_buf_out_validate,
 	.buf_prepare		= vid_out_buf_prepare,
 	.buf_queue		= vid_out_buf_queue,
 	.start_streaming	= vid_out_start_streaming,
-- 
2.19.2