mm: do not ignore mapping_gfp_mask in page cache allocation paths
authorMichal Hocko <mhocko@suse.cz>
Wed, 24 Jun 2015 23:58:06 +0000 (16:58 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 25 Jun 2015 00:49:44 +0000 (17:49 -0700)
commit6afdb859b71019143b8eecda02b8b29b03185055
tree4b7700350fc54a4e531dfd9f9d63c02be75ab4d3
parent0f96ae2928a547b86678688042a9759edcc8285d
mm: do not ignore mapping_gfp_mask in page cache allocation paths

page_cache_read, do_generic_file_read, __generic_file_splice_read and
__ntfs_grab_cache_pages currently ignore mapping_gfp_mask when calling
add_to_page_cache_lru which might cause recursion into fs down in the
direct reclaim path if the mapping really relies on GFP_NOFS semantic.

This doesn't seem to be the case now because page_cache_read (page fault
path) doesn't seem to suffer from the reclaim recursion issues and
do_generic_file_read and __generic_file_splice_read also shouldn't be
called under fs locks which would deadlock in the reclaim path.  Anyway it
is better to obey mapping gfp mask and prevent from later breakage.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/ntfs/file.c
fs/splice.c
mm/filemap.c