From ca9fe02221ae711d801d6c95b35cb5a757bce824 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Wed, 6 Sep 2017 16:20:00 -0700 Subject: BACKPORT: zram: identify asynchronous IO's return value For upcoming asynchronous IO like writeback, zram_rw_page should be aware of that whether requested IO was completed or submitted successfully, otherwise error. For the goal, zram_bvec_rw has three return values. -errno: returns error number 0: IO request is done synchronously 1: IO request is issued successfully. Link: http://lkml.kernel.org/r/1498459987-24562-7-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim Cc: Juneho Choi Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds (cherry picked from commit ae85a8075c5b025b9d503554ddc480a346a24536) Signed-off-by: Peter Kalauskas Bug: 112488418 Change-Id: Id6e764b3eacfebdca2f46050648a49fc5f276b2c Signed-off-by: Amit Pundir --- drivers/block/zram/zram_drv.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 79b5e9c774a7..df0d61dfa110 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -779,7 +779,7 @@ out: static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index) { - int ret; + int ret = 0; unsigned long alloced_pages; unsigned long handle = 0; unsigned int comp_len = 0; @@ -884,7 +884,7 @@ out: /* Update stats */ atomic64_inc(&zram->stats.pages_stored); - return 0; + return ret; } static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, @@ -966,6 +966,11 @@ static void zram_bio_discard(struct zram *zram, u32 index, } } +/* + * Returns errno if it has some problem. Otherwise return 0 or 1. + * Returns 0 if IO request was done synchronously + * Returns 1 if IO request was successfully submitted. + */ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, int offset, int rw) { @@ -986,7 +991,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, generic_end_io_acct(rw, &zram->disk->part0, start_time); - if (unlikely(ret)) { + if (unlikely(ret < 0)) { if (rw == READ) atomic64_inc(&zram->stats.failed_reads); else @@ -1075,7 +1080,7 @@ static void zram_slot_free_notify(struct block_device *bdev, static int zram_rw_page(struct block_device *bdev, sector_t sector, struct page *page, int rw) { - int offset, err = -EIO; + int offset, ret; u32 index; struct zram *zram; struct bio_vec bv; @@ -1084,7 +1089,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, if (!valid_io_request(zram, sector, PAGE_SIZE)) { atomic64_inc(&zram->stats.invalid_io); - err = -EINVAL; + ret = -EINVAL; goto out; } @@ -1095,7 +1100,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, bv.bv_len = PAGE_SIZE; bv.bv_offset = 0; - err = zram_bvec_rw(zram, &bv, index, offset, rw); + ret = zram_bvec_rw(zram, &bv, index, offset, rw); out: /* * If I/O fails, just return error(ie, non-zero) without @@ -1105,9 +1110,20 @@ out: * bio->bi_end_io does things to handle the error * (e.g., SetPageError, set_page_dirty and extra works). */ - if (err == 0) + if (unlikely(ret < 0)) + return ret; + + switch (ret) { + case 0: page_endio(page, rw, 0); - return err; + break; + case 1: + ret = 0; + break; + default: + WARN_ON(1); + } + return ret; } static void zram_reset_device(struct zram *zram) -- cgit v1.2.3