diff options
| author | Seth Jennings <sjenning@linux.vnet.ibm.com> | 2013-04-18 09:47:18 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-04-23 17:18:02 +1000 |
| commit | 030bcf3b4588dc0b521418a03e60cbf3fd7ba955 (patch) | |
| tree | 0f4f27b657b65fcc1385e8fbeeefe5a89cb6cecf /mm | |
| parent | b8ee7fc6356bdd2f2ccfa8781c320102fbb570be (diff) | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_io.c | 14 | ||||
| -rw-r--r-- | mm/swap_state.c | 2 |
2 files changed, 12 insertions, 4 deletions
diff --git a/mm/page_io.c b/mm/page_io.c index 8d3c0c088105..a08cb51fc09c 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -184,9 +184,7 @@ bad_bmap: */ int swap_writepage(struct page *page, struct writeback_control *wbc) { - struct bio *bio; - int ret = 0, rw = WRITE; - struct swap_info_struct *sis = page_swap_info(page); + int ret = 0; if (try_to_free_swap(page)) { unlock_page(page); @@ -198,6 +196,16 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) end_page_writeback(page); goto out; } + ret = __swap_writepage(page, wbc); +out: + return ret; +} + +int __swap_writepage(struct page *page, struct writeback_control *wbc) +{ + struct bio *bio; + int ret = 0, rw = WRITE; + struct swap_info_struct *sis = page_swap_info(page); if (sis->flags & SWP_FILE) { struct kiocb kiocb; diff --git a/mm/swap_state.c b/mm/swap_state.c index 7efcf1525921..fe43fd5578cf 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -78,7 +78,7 @@ void show_swap_cache_info(void) * __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space, * but sets SwapCache flag and private instead of mapping and index. */ -static int __add_to_swap_cache(struct page *page, swp_entry_t entry) +int __add_to_swap_cache(struct page *page, swp_entry_t entry) { int error; struct address_space *address_space; |