[lkml]   [2005]   [Dec]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: More info for DSM w/r/t sunffb on 2.6.15-rc6
On Sat, 24 Dec 2005, Linus Torvalds wrote:
> On Fri, 23 Dec 2005, David S. Miller wrote:
> >
> > + if (!(vma->vm_flags & VM_SHARED))
> > + return -EINVAL;
> > +
> Side note - as I explained to Nick the other week, VM_SHARED really means
> "shared _writable_" mapping, so you're now disallowing a shared read-only
> open too.
> Which may be fine, of course. Especially if sbusfb always ends up giving a
> writable pfn-mapping. But I wanted to check that that was what you meant
> to do.
> To test for MAP_SHARED, either do the is_cow_mapping() thing, or check
> the VM_MAYSHARE bit.

I wondered over that too. Concluded that at the moment it's right for
the test to be on VM_SHARED, because it's secretly giving away shared
write permission. But in future, once that's been corrected, such checks
would do better to check for VM_MAYSHARE (i.e. reject all MAP_PRIVATE).

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-12-24 10:19    [W:0.034 / U:1.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site