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? I'll work on fixing the other issues with the user <-> kernel transitions. Regards, Hartley _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
