Messages in this thread Patch in this message | | | From | Minchan Kim <> | Subject | [RFC 5/7] zram: identify asynchronous IO's return value | Date | Mon, 12 Jun 2017 14:02:49 +0900 |
| |
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.
Signed-off-by: Minchan Kim <minchan@kernel.org> --- 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 d82914e..f5924ef 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -897,7 +897,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index) { - int ret; + int ret = 0; struct zram_entry *uninitialized_var(entry); unsigned int uninitialized_var(comp_len); void *src, *dst, *mem; @@ -1014,7 +1014,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index) zram_slot_unlock(zram, index); atomic64_inc(&zram->stats.pages_stored); - return 0; + return ret; } static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, @@ -1096,6 +1096,11 @@ 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, bool is_write) { @@ -1117,7 +1122,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, generic_end_io_acct(rw_acct, &zram->disk->part0, start_time); - if (unlikely(ret)) { + if (unlikely(ret < 0)) { if (!is_write) atomic64_inc(&zram->stats.failed_reads); else @@ -1210,7 +1215,7 @@ 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, bool is_write) { - int offset, err = -EIO; + int offset, ret; u32 index; struct zram *zram; struct bio_vec bv; @@ -1219,7 +1224,7 @@ 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; } @@ -1230,7 +1235,7 @@ 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, is_write); + ret = zram_bvec_rw(zram, &bv, index, offset, is_write); out: /* * If I/O fails, just return error(ie, non-zero) without @@ -1240,9 +1245,20 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, * 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, is_write, 0); - return err; + break; + case 1: + ret = 0; + break; + default: + WARN_ON(1); + } + return ret; } static void zram_reset_device(struct zram *zram) -- 2.7.4
| |