[PATCH v1 1/9] zram: clean up duplicated codes in __zram_bvec_write

Minchan Kim
2017-06-26T06:53:28Z

__zram_bvec_write has some of duplicated logic for zram meta data
handling of same_page|compressed_page. This patch aims to clean it up
without behavior change.

Link: http://lkml.kernel.org/r/1496019048-27016-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
drivers/block/zram/zram_drv.c | 55 +++++++++++++++++--------------------------
1 file changed, 22 insertions(+), 33 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index d3e3af2..5d3ea405 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -453,30 +453,6 @@ static bool zram_same_page_read(struct zram *zram, u32 index,
return false;
}

-static bool zram_same_page_write(struct zram *zram, u32 index,
- struct page *page)
-{
- unsigned long element;
- void *mem = kmap_atomic(page);
-
- if (page_same_filled(mem, &element)) {
- kunmap_atomic(mem);
- /* Free memory associated with this sector now. */
- zram_slot_lock(zram, index);
- zram_free_page(zram, index);
- zram_set_flag(zram, index, ZRAM_SAME);
- zram_set_element(zram, index, element);
- zram_slot_unlock(zram, index);
-
- atomic64_inc(&zram->stats.same_pages);
- atomic64_inc(&zram->stats.pages_stored);
- return true;
- }
- kunmap_atomic(mem);
-
- return false;
-}
-
static void zram_meta_free(struct zram *zram, u64 disksize)
{
size_t num_pages = disksize >> PAGE_SHIFT;
@@ -685,14 +661,23 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
{
int ret;
- unsigned long handle;
- unsigned int comp_len;
- void *src, *dst;
+ unsigned long handle = 0;
+ unsigned int comp_len = 0;
+ void *src, *dst, *mem;
struct zcomp_strm *zstrm;
struct page *page = bvec->bv_page;
+ unsigned long element = 0;
+ enum zram_pageflags flags = 0;

- if (zram_same_page_write(zram, index, page))
- return 0;
+ mem = kmap_atomic(page);
+ if (page_same_filled(mem, &element)) {
+ kunmap_atomic(mem);
+ /* Free memory associated with this sector now */
+ atomic64_inc(&zram->stats.same_pages);
+ flags = ZRAM_SAME;
+ goto out;
+ }
+ kunmap_atomic(mem);

zstrm = zcomp_stream_get(zram->comp);
ret = zram_compress(zram, &zstrm, page, &handle, &comp_len);
@@ -712,19 +697,23 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)

zcomp_stream_put(zram->comp);
zs_unmap_object(zram->mem_pool, handle);
-
+out:
/*
* Free memory associated with this sector
* before overwriting unused sectors.
*/
zram_slot_lock(zram, index);
zram_free_page(zram, index);
- zram_set_handle(zram, index, handle);
- zram_set_obj_size(zram, index, comp_len);
+ if (flags == ZRAM_SAME) {
+ zram_set_flag(zram, index, ZRAM_SAME);
+ zram_set_element(zram, index, element);
+ } else {
+ zram_set_handle(zram, index, handle);
+ zram_set_obj_size(zram, index, comp_len);
+ }
zram_slot_unlock(zram, index);

/* Update stats */
- atomic64_add(comp_len, &zram->stats.compr_data_size);
atomic64_inc(&zram->stats.pages_stored);
return 0;
}
--
2.7.4