On Tue, Mar 03, 2015 at 12:23:59PM +0100, Hans Verkuil wrote: > Return -EINVAL if read() or write() is not supported by the queue. This > makes it possible to provide both vb2_fop_read and vb2_fop_write in a > struct v4l2_file_operations since the vb2_fop_* function will check if > the file operation is allowed. > > A similar check exists in __vb2_init_fileio() which is called from > __vb2_perform_fileio(), but that check is only done if no file I/O is > active. So the sequence of read() followed by write() would be allowed, > which is obviously a bug. > > In addition, vb2_fop_write/read should always return -EINVAL if the > operation is not allowed, and by putting the check in the lower levels > of the code it is possible that other error codes are returned (EBUSY > or ERESTARTSYS). > > All these issues are avoided by just doing a quick explicit check. > > Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> -- Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
