From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: phillips@arcor.de, akpm@digeo.com, hch@infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race
Date: Thu, 29 May 2003 19:38:26 -0700 [thread overview]
Message-ID: <20030530023826.GA1350@us.ibm.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0305291723310.1800-100000@localhost.localdomain>
On Thu, May 29, 2003 at 05:33:04PM +0100, Hugh Dickins wrote:
> 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.
Fine by me either way. ;-) Here is the rediffed nopagedone patch
for 2.5.70-mm1.
Thanx, Paul
diff -urN -X dontdiff linux-2.5.70-mm1/include/linux/mm.h linux-2.5.70-mm1.nopagedone/include/linux/mm.h
--- linux-2.5.70-mm1/include/linux/mm.h 2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.nopagedone/include/linux/mm.h 2003-05-29 19:34:55.000000000 -0700
@@ -143,6 +143,7 @@
void (*open)(struct vm_area_struct * area);
void (*close)(struct vm_area_struct * area);
struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int unused);
+ void (*nopagedone)(struct vm_area_struct * area, unsigned long address, int status);
int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
};
diff -urN -X dontdiff linux-2.5.70-mm1/mm/memory.c linux-2.5.70-mm1.nopagedone/mm/memory.c
--- linux-2.5.70-mm1/mm/memory.c 2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.nopagedone/mm/memory.c 2003-05-29 19:34:55.000000000 -0700
@@ -1468,6 +1468,9 @@
ret = VM_FAULT_OOM;
out:
pte_chain_free(pte_chain);
+ if (vma->vm_ops && vma->vm_ops->nopagedone) {
+ vma->vm_ops->nopagedone(vma, address & PAGE_MASK, ret);
+ }
return ret;
}
next prev parent reply other threads:[~2003-05-30 16:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-23 18:42 [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race Paul E. McKenney
2003-05-29 15:14 ` Paul E. McKenney
2003-05-29 15:18 ` [RFC][PATCH] Remove LINUX_2_2 Paul E. McKenney
2003-05-29 16:33 ` [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race Hugh Dickins
2003-05-29 17:15 ` Daniel Phillips
2003-05-29 17:39 ` Daniel Phillips
2003-05-29 20:24 ` Paul E. McKenney
2003-05-30 2:38 ` Paul E. McKenney [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-05-17 18:21 [RFC][PATCH] vm_operation to avoid pagefault/inval race Daniel Phillips
2003-05-17 19:49 ` Andrew Morton
2003-05-20 1:23 ` Paul E. McKenney
2003-05-20 8:11 ` Andrew Morton
2003-05-23 14:35 ` [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race Paul E. McKenney
2003-05-23 16:21 ` Hugh Dickins
2003-05-23 17:10 ` Daniel Phillips
2003-05-23 17:47 ` Hugh Dickins
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