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author | Mel Gorman <mgorman@suse.de> | 2012-07-31 16:44:47 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-31 18:42:47 -0700 |
commit | f981c5950fa85916ba49bea5d9a7a5078f47e569 (patch) | |
tree | e742598755e57e1bbed06dc90b05fe6e13091236 /include/linux/pagemap.h | |
parent | 6290c2c439732727899405f39fb76c2f5585b707 (diff) | |
download | lwn-f981c5950fa85916ba49bea5d9a7a5078f47e569.tar.gz lwn-f981c5950fa85916ba49bea5d9a7a5078f47e569.zip |
mm: methods for teaching filesystems about PG_swapcache pages
In order to teach filesystems to handle swap cache pages, three new page
functions are introduced:
pgoff_t page_file_index(struct page *);
loff_t page_file_offset(struct page *);
struct address_space *page_file_mapping(struct page *);
page_file_index() - gives the offset of this page in the file in
PAGE_CACHE_SIZE blocks. Like page->index is for mapped pages, this
function also gives the correct index for PG_swapcache pages.
page_file_offset() - uses page_file_index(), so that it will give the
expected result, even for PG_swapcache pages.
page_file_mapping() - gives the mapping backing the actual page; that is
for swap cache pages it will give swap_file->f_mapping.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pagemap.h')
-rw-r--r-- | include/linux/pagemap.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 7cfad3bbb0cc..e42c762f0dc7 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -286,6 +286,11 @@ static inline loff_t page_offset(struct page *page) return ((loff_t)page->index) << PAGE_CACHE_SHIFT; } +static inline loff_t page_file_offset(struct page *page) +{ + return ((loff_t)page_file_index(page)) << PAGE_CACHE_SHIFT; +} + extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma, unsigned long address); |