On Tuesday 21 August 2012, Catalin Marinas wrote:
> > > +asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
> > > + unsigned long prot, unsigned long flags,
> > > + unsigned long fd, off_t off)
> > > +{
> > > + if (offset_in_page(off) != 0)
> > > + return -EINVAL;
> > > +
> > > + return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
> > > +}
> >
> > I think
> >
> > #define sys_mmap sys_mmap_pgoff
>
> There are slightly different semantics with the last argument of
> sys_mmap() which takes a byte offset. The sys_mmap_pgoff() function
> takes the offset shifted by PAGE_SHIFT (which is the same as sys_mmap2).
>
> Looking at the other architectures, it makes sense to use a generic
> sys_mmap() implementation similar to the one above (or the ia-64, seems
> to be the most complete).
>
Why that? The generic sys_mmap_pgoff was specifically added so new architectures
could just use that instead of having their own wrappers, see f8b72560.
Arnd
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