From a1156cbb71f4ed745f8a14719d9307813e3c9151 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@kernel.org>
Date: Wed, 6 Sep 2017 16:20:00 -0700
Subject: [PATCH] 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 <minchan@kernel.org>
Cc: Juneho Choi <juno.choi@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit ae85a8075c5b025b9d503554ddc480a346a24536)
Signed-off-by: Peter Kalauskas <peskal@google.com>
Bug: 112488418
Change-Id: Id6e764b3eacfebdca2f46050648a49fc5f276b2c
---
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)
--
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