On Wed, May 09, 2012 at 10:52:34AM -0500, H Hartley Sweeten wrote: > On Wednesday, May 09, 2012 7:25 AM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > On Wed, May 09, 2012 at 11:20:07AM +0100, Ian Abbott wrote: > >> On 2012-05-09 00:55, H Hartley Sweeten wrote: > >>> On Tuesday, May 08, 2012 4:41 PM, H Hartley Sweeten wrote: > >>>> > >>>> The structs' comedi_insn, coomedi_insnlist, comedi_cmd, > >>>> comedi_chaninfo, and comedi_rangeinfo are all passed to > >>>> the kernel from user space using ioctl commands. They > >>>> are then copied to kernel space using copy_from_user() > >>>> before the data is passed to the drivers. > >>>> > >>>> The __user annotation should not be used with variables > >>>> inside the struct. This produces a lot of sparse warnings > >>>> like: > >>>> > >>>>warning: dereference of noderef expression > >>>> > >>>> Signed-off-by: H Hartley Sweeten<hsweeten@xxxxxxxxxxxxxxxxxxx> > >>>> Cc: Ian Abbott<abbotti@xxxxxxxxx> > >>>> Cc: Mori Hess<fmhess@xxxxxxxxxxxxxxxxxxxxx> > >>>> Cc: Greg Kroah-Hartman<gregkh@xxxxxxxxxxxxxxxxxxx> > >>>> > >>>> --- > >>>> > >>>> Note: This patch exposes some new warnings about different > >>>> address space. These will be addressed. > >>> > >>> Please ignore this patch. > >>> > >>> It appears the annotations in the struct definitions are correct. > >> > >> Personally, I think you were on the mark with the patch. It's > >> better to avoid using __user in comedi.h so it can be used as-is in > >> user-space. All of the structures in comedi.h are used in user-space > >> (although Comedilib uses its own version of comedi.h without all the > >> typedef eliminations that have been done in "staging") and some of > >> them are also deep-copied into kernel-space objects of the same > >> type, where the pointers in the structs would no longer be > >> user-space pointers. > > > > When the kernel exports .h files, stuff like this should work > > "automatically", so there is no need to not put __user markings. > > > > So please, yes, continue to work to get this correct, it is very > > essencial to ensure we don't mess stuff up. > > Greg, > > Based on the discussion I assume this patch is ok then. Do you > want me to repost it? Sure, I'll review it with the other patches you have sent later today. > I'll work on fixing the other issues with the user <-> kernel transitions. Wonderful, thanks for the work you are doing on this code, it's greatly appreciated. greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
