Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Hugh Dickins]

On Thu, 29 May 2003, Paul E. McKenney wrote:
> On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote:
> > 
> > Exactly -- allows a ->nopage() to drop some lock to avoid races
> > between pagefault and either vmtruncate() or invalidate_mmap_range().
> > This race (from the cross-host mmap viewpoint) is described in:
> > 
> >     http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2
> 
> Rediffed for 2.5.70-mm1.

Me?  I much preferred your original, much sparer, nopagedone patch
(labelled "uglyh as hell" by hch).  I dislike passing lots of args
down a level so they can be passed up again to the library function.

In particular, I feel queasy (fear loss of control) about passing a
pmd_t* down to a filesystem, which I'd prefer to have no access to
such.  But I may be in a minority, and the decision won't be mine.

Hugh