On Tue, 7 Feb 2012, Konstantin Khlebnikov wrote: > Bug was added in commit v3.0-7291-g8079b1c (mm: clarify the radix_tree > exceptional cases) > So, v3.1 and v3.2 affected. > > Konstantin Khlebnikov wrote: > > It should return NULL, otherwise the caller will be very surprised. > > > > Signed-off-by: Konstantin Khlebnikov<khlebnikov@xxxxxxxxxx> Thanks for worrying about it, but Nak to this patch. If you have found somewhere that is surprised by an exceptional entry instead of a page, then indeed we shall need to fix that: I'm not aware of any. There are several places that are prepared for the possibility: find_lock_page() (and your patch would be breaking shmem.c's use of find_lock_page()), mincore_page(), memcontrol.c's mc_handle_file_pte(). Of the remaining calls to find_get_page(), my understanding is that either they are filesystems operating upon their own pagecache, or they involve using ->readpage() - that's one of the two reasons why I gave shmem its own ->splice_read() and removed its ->readpage() before switching over to use the exceptional entries. Hugh > > --- > > mm/filemap.c | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/mm/filemap.c b/mm/filemap.c > > index 518223b..ca98cb5 100644 > > --- a/mm/filemap.c > > +++ b/mm/filemap.c > > @@ -693,6 +693,7 @@ repeat: > > * here as an exceptional entry: so return it without > > * attempting to raise page count. > > */ > > + page = NULL; > > goto out; > > } > > if (!page_cache_get_speculative(page)) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>