lkml.org 
[lkml]   [2015]   [Jun]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC 1/2] mm: do not ignore mapping_gfp_mask in page cache allocation paths
Date
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.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
---
fs/ntfs/file.c | 2 +-
fs/splice.c | 2 +-
mm/filemap.c | 6 ++++--
3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 1da9b2d184dc..568c9dbc7e61 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -422,7 +422,7 @@ static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
}
}
err = add_to_page_cache_lru(*cached_page, mapping, index,
- GFP_KERNEL);
+ GFP_KERNEL & mapping_gfp_mask(mapping));
if (unlikely(err)) {
if (err == -EEXIST)
continue;
diff --git a/fs/splice.c b/fs/splice.c
index 7d2fbb788fc5..ebd184f24e0d 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -360,7 +360,7 @@ __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 df533a10e8c3..adfc5d2e21c8 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1669,7 +1669,8 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
goto out;
}
error = add_to_page_cache_lru(page, mapping,
- index, GFP_KERNEL);
+ index,
+ GFP_KERNEL & mapping_gfp_mask(mapping));
if (error) {
page_cache_release(page);
if (error == -EEXIST) {
@@ -1770,7 +1771,8 @@ 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)
--
2.1.4


\
 
 \ /
  Last update: 2015-06-01 15:41    [W:0.647 / U:0.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site