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Subject[RFCv3 04/17] media: vb2: add support for requests in QBUF ioctl
Date
Support the request argument of the QBUF ioctl.

Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
---
drivers/media/v4l2-core/v4l2-ioctl.c | 83 +++++++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 2f40ac0cdf6e..235acdde3111 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -29,6 +29,7 @@
#include <media/v4l2-device.h>
#include <media/videobuf2-v4l2.h>
#include <media/v4l2-mc.h>
+#include <media/media-request.h>

#include <trace/events/v4l2.h>

@@ -968,6 +969,71 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
return -EINVAL;
}

+/*
+ * Validate that a given request can be used during an ioctl.
+ *
+ * When using the request API, request file descriptors must be matched against
+ * the actual request object. User-space can pass any file descriptor, so we
+ * need to make sure the call is valid before going further.
+ *
+ * This function looks up the request and associated data and performs the
+ * following sanity checks:
+ *
+ * * Make sure that the entity belongs to the media_device managing the passed
+ * request,
+ * * Make sure that the entity data (if any) is associated to the current file
+ * handler.
+ *
+ * This function returns a pointer to the valid request, or and error code in
+ * case of failure. When successful, a reference to the request is acquired and
+ * must be properly released by the caller. If _data is not NULL, then it is
+ * filled with a pointer to the corresponding entity data.
+ */
+#ifdef CONFIG_MEDIA_CONTROLLER
+static struct media_request *
+check_request(int request, struct file *file, void *fh, struct media_request_entity_data **_data)
+{
+ struct media_request *req = NULL;
+ struct video_device *vfd = video_devdata(file);
+ struct v4l2_fh *vfh =
+ test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct media_entity *entity = &vfd->entity;
+ struct media_request_entity_data *data;
+
+ if (!entity)
+ return ERR_PTR(-EINVAL);
+
+ req = media_request_get_from_fd(request);
+ if (!req)
+ return ERR_PTR(-EINVAL);
+
+ /* Validate that the entity belongs to the correct media_device */
+ if (vfd->v4l2_dev->mdev->req_mgr != req->mgr) {
+ media_request_put(req);
+ return ERR_PTR(-EINVAL);
+ }
+
+ /* Validate that the entity's data belongs to the correct fh */
+ data = media_request_get_entity_data(req, entity, vfh);
+ if (IS_ERR(data)) {
+ media_request_put(req);
+ return ERR_PTR(PTR_ERR(data));
+ }
+
+ if (_data)
+ *_data = data;
+
+ return req;
+}
+#else /* CONFIG_MEDIA_CONTROLLER */
+static struct media_request *
+check_request(int request, struct file *file, void *fh)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
+#endif /* CONFIG_MEDIA_CONTROLLER */
+
static void v4l_sanitize_format(struct v4l2_format *fmt)
{
unsigned int offset;
@@ -1878,10 +1944,25 @@ static int v4l_querybuf(const struct v4l2_ioctl_ops *ops,
static int v4l_qbuf(const struct v4l2_ioctl_ops *ops,
struct file *file, void *fh, void *arg)
{
+ struct media_request *req = NULL;
struct v4l2_buffer *p = arg;
int ret = check_fmt(file, p->type);

- return ret ? ret : ops->vidioc_qbuf(file, fh, p);
+ if (ret)
+ return ret;
+
+ if (p->request_fd > 0) {
+ req = check_request(p->request_fd, file, fh, NULL);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+ }
+
+ ret = ops->vidioc_qbuf(file, fh, p);
+
+ if (req)
+ media_request_put(req);
+
+ return ret;
}

static int v4l_dqbuf(const struct v4l2_ioctl_ops *ops,
--
2.16.0.rc1.238.g530d649a79-goog
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