media: media requests: return EBADR instead of EACCES

If requests are used when they shouldn't, or not used when they should,
then return EBADR (Invalid request descriptor) instead of EACCES.

The reason for this change is that EACCES has more to do with permissions
(not being the owner of the resource), but in this case the request file
descriptor is just wrong for the current mode of the device.

Update the documentation accordingly.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

6 files changed, 12 insertions, 14 deletions

diff --git a/Documentation/media/uapi/mediactl/request-api.rst b/Documentation/media/uapi/mediactl/request-api.rst
index 1ad631e549fe..a74c82d95609 100644
--- a/Documentation/media/uapi/mediactl/request-api.rst
+++ b/Documentation/media/uapi/mediactl/request-api.rst
@@ -93,7 +93,7 @@ A queued request cannot be modified anymore.
 .. caution::
    For :ref:`memory-to-memory devices <mem2mem>` you can use requests only for
    output buffers, not for capture buffers. Attempting to add a capture buffer
-   to a request will result in an ``EACCES`` error.
+   to a request will result in an ``EBADR`` error.
 
 If the request contains configurations for multiple entities, individual drivers
 may synchronize so the requested pipeline's topology is applied before the
diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst
index 81ffdcb89057..b9a2e9dc707c 100644
--- a/Documentation/media/uapi/v4l/buffer.rst
+++ b/Documentation/media/uapi/v4l/buffer.rst
@@ -326,7 +326,7 @@ struct v4l2_buffer
 	Applications should not set ``V4L2_BUF_FLAG_REQUEST_FD`` for any ioctls
 	other than :ref:`VIDIOC_QBUF <VIDIOC_QBUF>`.
 
-	If the device does not support requests, then ``EACCES`` will be returned.
+	If the device does not support requests, then ``EBADR`` will be returned.
 	If requests are supported but an invalid request file descriptor is
 	given, then ``EINVAL`` will be returned.
 
diff --git a/Documentation/media/uapi/v4l/vidioc-qbuf.rst b/Documentation/media/uapi/v4l/vidioc-qbuf.rst
index 5739c3676062..dbf7b445a27b 100644
--- a/Documentation/media/uapi/v4l/vidioc-qbuf.rst
+++ b/Documentation/media/uapi/v4l/vidioc-qbuf.rst
@@ -111,7 +111,7 @@ in use. Setting it means that the buffer will not be passed to the driver
 until the request itself is queued. Also, the driver will apply any
 settings associated with the request for this buffer. This field will
 be ignored unless the ``V4L2_BUF_FLAG_REQUEST_FD`` flag is set.
-If the device does not support requests, then ``EACCES`` will be returned.
+If the device does not support requests, then ``EBADR`` will be returned.
 If requests are supported but an invalid request file descriptor is given,
 then ``EINVAL`` will be returned.
 
@@ -125,7 +125,7 @@ then ``EINVAL`` will be returned.
 
    For :ref:`memory-to-memory devices <mem2mem>` you can specify the
    ``request_fd`` only for output buffers, not for capture buffers. Attempting
-   to specify this for a capture buffer will result in an ``EACCES`` error.
+   to specify this for a capture buffer will result in an ``EBADR`` error.
 
 Applications call the ``VIDIOC_DQBUF`` ioctl to dequeue a filled
 (capturing) or displayed (output) buffer from the driver's outgoing
@@ -185,12 +185,10 @@ EPIPE
     codecs if a buffer with the ``V4L2_BUF_FLAG_LAST`` was already
     dequeued and no new buffers are expected to become available.
 
-EACCES
-    The ``V4L2_BUF_FLAG_REQUEST_FD`` flag was set but the device does not
-    support requests for the given buffer type.
-
 EBADR
-    The ``V4L2_BUF_FLAG_REQUEST_FD`` flag was not set but the device requires
+    The ``V4L2_BUF_FLAG_REQUEST_FD`` flag was set but the device does not
+    support requests for the given buffer type, or
+    the ``V4L2_BUF_FLAG_REQUEST_FD`` flag was not set but the device requires
     that the buffer is part of a request.
 
 EBUSY
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 84de18b30a95..b11a779e97b0 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -392,7 +392,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
 		return 0;
 	} else if (!q->supports_requests) {
 		dprintk(1, "%s: queue does not support requests\n", opname);
-		return -EACCES;
+		return -EBADR;
 	} else if (q->uses_qbuf) {
 		dprintk(1, "%s: queue does not use requests\n", opname);
 		return -EBUSY;
diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
index eec2e2b2f6ec..ed87305b29f9 100644
--- a/drivers/media/media-request.c
+++ b/drivers/media/media-request.c
@@ -251,7 +251,7 @@ media_request_get_by_fd(struct media_device *mdev, int request_fd)
 
 	if (!mdev || !mdev->ops ||
 	    !mdev->ops->req_validate || !mdev->ops->req_queue)
-		return ERR_PTR(-EACCES);
+		return ERR_PTR(-EBADR);
 
 	filp = fget(request_fd);
 	if (!filp)
@@ -407,7 +407,7 @@ int media_request_object_bind(struct media_request *req,
 	int ret = -EBUSY;
 
 	if (WARN_ON(!ops->release))
-		return -EACCES;
+		return -EBADR;
 
 	spin_lock_irqsave(&req->lock, flags);
 
diff --git a/include/media/media-request.h b/include/media/media-request.h
index bd36d7431698..3cd25a2717ce 100644
--- a/include/media/media-request.h
+++ b/include/media/media-request.h
@@ -198,7 +198,7 @@ void media_request_put(struct media_request *req);
  * Get the request represented by @request_fd that is owned
  * by the media device.
  *
- * Return a -EACCES error pointer if requests are not supported
+ * Return a -EBADR error pointer if requests are not supported
  * by this driver. Return -EINVAL if the request was not found.
  * Return the pointer to the request if found: the caller will
  * have to call @media_request_put when it finished using the
@@ -231,7 +231,7 @@ static inline void media_request_put(struct media_request *req)
 static inline struct media_request *
 media_request_get_by_fd(struct media_device *mdev, int request_fd)
 {
-	return ERR_PTR(-EACCES);
+	return ERR_PTR(-EBADR);
 }
 
 #endif