Hi Sakari, On Sunday 17 June 2012 10:54:32 Sakari Ailus wrote: > On Sun, Jun 17, 2012 at 12:03:06AM +0200, Laurent Pinchart wrote: > > On Monday 11 June 2012 12:39:44 Sakari Ailus wrote: > > > On Mon, Jun 11, 2012 at 09:50:54AM +0200, Laurent Pinchart wrote: > > > > On Sunday 10 June 2012 23:22:59 Sakari Ailus wrote: > > > > > Hi Mauro, > > > > > > > > > > Here are two V4L2 API cleanup patches; the first removes __user from > > > > > videodev2.h from a few places, making it possible to use the header > > > > > file > > > > > as such in user space, while the second one changes the > > > > > v4l2_buffer.input field back to reserved. > > > > > > > > > > The following changes since commit > > > > 5472d3f17845c4398c6a510b46855820920c2181: > > > > > [media] mt9m032: Implement V4L2_CID_PIXEL_RATE control (2012-05-24 > > > > > > > > > > 09:27:24 -0300) > > > > > > > > > > are available in the git repository at: > > > > > ssh://linuxtv.org/git/sailus/media_tree.git media-for-3.6 > > > > > > > > > > Sakari Ailus (2): > > > > > v4l: Remove __user from interface structure definitions > > > > > > > > NAK, sorry. > > > > > > > > __user has a purpose, we need to add it where it's missing, not remove > > > > it where it's rightfully present. > > > > > > It's not quite as simple as adding __user everywhere it might belong to > > > --- > > > these structs are being used in kernel space, too. The structs that are > > > part of the user space interface may at some point contain pointers to > > > memory which is in user space. That is being dealt by video_usercopy(), > > > so the individual drivers or the rest of the V4L2 framework always gets > > > pointers pointing to kernel memory. > > > > Very good point, I haven't thought about that. I'm not sure how to deal > > with this, splitting structures in a __user and a non __user version > > isn't really a good option. Maybe the sparse tool should be somehow > > extended ? > > Wouldn't type casting in video_usercopy() just do the job? Albeit I'm far > from certain it'd make the code better, just make the sparse warnings go > away... For pointers that are completely handled in the v4l core (such as the v4l2_buffer and v4l2_ext_controls pointer fields), casting casting in video_usercopy() is enough as no driver will ever see the user pointers (we already cast in those cases). For pointers that are to be handled by drivers, I think we need to keep __user (or make the v4l core handle them). -- Regards, Laurent Pinchart -- 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
