From: Michal Hocko <mhocko@suse.cz>
Date: Wed, 24 Jun 2015 23:58:06 +0000 (-0700)
Subject: mm: do not ignore mapping_gfp_mask in page cache allocation paths
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=6afdb859b71019143b8eecda02b8b29b03185055;p=openwrt%2Fstaging%2Fblogic.git

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>
---

diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 7bb487e663b4..2cd653670764 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -525,7 +525,8 @@ static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
 				}
 			}
 			err = add_to_page_cache_lru(*cached_page, mapping,
-					index, GFP_KERNEL);
+					index,
+					GFP_KERNEL & mapping_gfp_mask(mapping));
 			if (unlikely(err)) {
 				if (err == -EEXIST)
 					continue;
diff --git a/fs/splice.c b/fs/splice.c
index bfe62ae40f40..0efef17e9bfa 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -359,7 +359,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 				break;
 
 			error = add_to_page_cache_lru(page, mapping, index,
-						GFP_KERNEL);
+					GFP_KERNEL & mapping_gfp_mask(mapping));
 			if (unlikely(error)) {
 				page_cache_release(page);
 				if (error == -EEXIST)
diff --git a/mm/filemap.c b/mm/filemap.c
index 519af0045b1c..8d17ceea8dbe 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1664,8 +1664,8 @@ no_cached_page:
 			error = -ENOMEM;
 			goto out;
 		}
-		error = add_to_page_cache_lru(page, mapping,
-						index, GFP_KERNEL);
+		error = add_to_page_cache_lru(page, mapping, index,
+					GFP_KERNEL & mapping_gfp_mask(mapping));
 		if (error) {
 			page_cache_release(page);
 			if (error == -EEXIST) {
@@ -1766,7 +1766,8 @@ static int page_cache_read(struct file *file, pgoff_t offset)
 		if (!page)
 			return -ENOMEM;
 
-		ret = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL);
+		ret = add_to_page_cache_lru(page, mapping, offset,
+				GFP_KERNEL & mapping_gfp_mask(mapping));
 		if (ret == 0)
 			ret = mapping->a_ops->readpage(file, page);
 		else if (ret == -EEXIST)