Hi! > From: Julia Lawall <[EMAIL PROTECTED]> > > In the patch cc154ac64aa8d3396b187f64cef01ce67f433324, Al Viro observed > that the proper way to compute the distance between two structure fields is > to use offsetof() or a cast to a pointer to character. The same change can > be applied to a few more files. > > The change was made using the following semantic patch > (http://www.emn.fr/x-info/coccinelle/) > > // <smpl> > @r@ > type T; > T s; > type T1, T2; > identifier fld1, fld2; > typedef uint8_t; > typedef u8; > @@ > > ( > (char *)&s.fld1 - (char *)&s.fld2 > | > (uint8_t *)&s.fld1 - (uint8_t *)&s.fld2 > | > (u8 *)&s.fld1 - (u8 *)&s.fld2 > | > - (T1)&s.fld1 - (T2)&s.fld2 > + offsetof(T,fld1) - offsetof(T,fld2) > ) > // </smpl> > > Signed-off-by: Julia Lawall <[EMAIL PROTECTED]> > --- > > diff -u -p a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c > --- a/arch/x86/kernel/vm86_32.c 2007-10-22 11:25:00.000000000 +0200 > +++ b/arch/x86/kernel/vm86_32.c 2007-12-26 16:27:15.000000000 +0100 > @@ -215,7 +215,9 @@ asmlinkage int sys_vm86old(struct pt_reg > ret = -EFAULT; > if (tmp) > goto out; > - memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); > + memset(&info.vm86plus, 0, > + offsetof(struct kernel_vm86_struct, regs32) - > + offsetof(struct kernel_vm86_struct, vm86plus));
I do not think this makes it more readable... (int) -> (char *) would make it portable and readable, AFAICT. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/