Re: [PATCH 10/13] mm: Wire up MAP_SYNC

[Jan Kara <jack@suse.cz>]

On Mon 21-08-17 15:37:04, Ross Zwisler wrote:
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index f19efcf75418..18453c04b09f 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -1423,12 +1423,17 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
> >  				return -ENODEV;
> >  			if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
> >  				return -EINVAL;
> > +			if (!(vm_flags & VM_SHARED) && (vm_flags & VM_SYNC))
> > +				return -EINVAL;
> 
> I know this will be reworked with Dan's new mmap() interface, but I was
> curious what the !(vm_flags & VM_SHARED) check here was for.  We're in a
> MAP_PRIVATE case, so is it ever possible for VM_SHARED to be set in vm_flags?
> I tried to make this happen with some various test scenarios, but wasn't able.

I was also caught by this :). Check how MAP_SHARED case above falls through
to the MAP_PRIVATE case...

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR