Re: [patch] rfc: fix splice mapping race?

[Nick Piggin]

On Sun, Jun 18, 2006 at 12:02:45PM +0200, Peter Zijlstra wrote:
> > In page migration, detect the missing mapping early and bail out if
> > that is the case: the page is not going to get un-truncated, so
> > retrying is just a waste of time.
> > 
> > Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
> 
> Looks sane, except the change in migrate (comment there). I like the
> remove_mapping() pre-conditions.

Thanks.

> > --- linux-2.6.orig/mm/migrate.c
> > +++ linux-2.6/mm/migrate.c
> > @@ -136,9 +136,13 @@ static int swap_page(struct page *page)
> >  {
> >  	struct address_space *mapping = page_mapping(page);
> >  
> > -	if (page_mapped(page) && mapping)
> > +	if (!mapping)
> > +		return -EINVAL; /* page truncated. signal permanent failure */
> 
> Here, I think you need to unlock the page too.

Bah, yes thanks... I'll post an updated patch after others have
had time to comment.

Nick
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