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authorSeth Jennings <sjenning@linux.vnet.ibm.com>2013-04-29 15:08:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-29 15:54:38 -0700
commit2f772e6cadf8ad8fca38927b17e6be028be669f5 (patch)
tree5eac4cfd72c6e8e9b4d48ad7463cdf1a8b97f7b4 /include
parente8420a8ece80b3fe810415ecf061d54ca7fab266 (diff)
downloadlinux-2f772e6cadf8ad8fca38927b17e6be028be669f5.tar.gz
mm: break up swap_writepage() for frontswap backends
swap_writepage() is currently where frontswap hooks into the swap write path to capture pages with the frontswap_store() function. However, if a frontswap backend wants to "resume" the writeback of a page to the swap device, it can't call swap_writepage() as the page will simply reenter the backend. This patch separates swap_writepage() into a top and bottom half, the bottom half named __swap_writepage() to allow a frontswap backend, like zswap, to resume writeback beyond the frontswap_store() hook. __add_to_swap_cache() is also made non-static so that the page for which writeback is to be resumed can be added to the swap cache. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Acked-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/swap.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2818a123f3e..76f6c3b3123 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -330,6 +330,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
/* linux/mm/page_io.c */
extern int swap_readpage(struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern int __swap_writepage(struct page *page, struct writeback_control *wbc);
extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
@@ -345,6 +346,7 @@ extern unsigned long total_swapcache_pages(void);
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
+extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);