On Tue, Sep 18, 2018 at 10:51:08AM -0700, Darren Hart wrote: > On Fri, Sep 14, 2018 at 09:57:48PM +0100, Al Viro wrote: > > On Fri, Sep 14, 2018 at 01:35:06PM -0700, Darren Hart wrote: > > > > > Acked-by: Darren Hart (VMware) <dvhart@xxxxxxxxxxxxx> > > > > > > As for a longer term solution, would it be possible to init fops in such > > > a way that the compat_ioctl call defaults to generic_compat_ioctl_ptrarg > > > so we don't have to duplicate this boilerplate for every ioctl fops > > > structure? > > > > Bad idea, that... Because several years down the road somebody will add > > an ioctl that takes an unsigned int for argument. Without so much as looking > > at your magical mystery macro being used to initialize file_operations. > > Fair, being explicit in the declaration as it is currently may be > preferable then. It would be much cleaner and safer if you could arrange things to add something like this to struct file_operations: long (*ptr_ioctl) (struct file *, unsigned int, void __user *); Where the core code automatically converts the unsigned long to the void __user * as appropriate. Then it just works right always and the compiler will help address Al's concern down the road. Cheers, Jason
