Re: [PATCH] Permit big console scrolls

[Andrew Morton <akpm@digeo.com>]

Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> On Sun, 22 Jun 2003, Andrew Morton wrote:
> > Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > >
> > > > -			if (get_user(lines, (char *)arg+1)) {
> > >  						    ^^^^^
> > >  > +			if (get_user(lines, (s32 *)((char *)arg+4))) {
> > >  							    ^^^^^
> > >  >  				ret = -EFAULT;
> > >  >  			} else {
> > >  >  				scrollfront(lines);
> > > 
> > >  Why was the `arg+1' changed to `arg+4'? Do we really want to skip 12 bytes?
> > 
> > It skips three bytes?
> 
> Oops, you're right. But my first question remains: why skip 3 bytes?

Well we want to use a 32-bit quantity, not an 8-bit one.  So Samuel aligned
that quantity 32 bits beyond the 8-bit ioctl `type' arg.

So I guess you'd do:

	struct foo {
		char type;
		char pad[3];
		s32 distance;
	};