LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Juneho Choi <juno.choi@lge.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	kernel-team <kernel-team@lge.com>,
	Minchan Kim <minchan@kernel.org>
Subject: [PATCH v1 6/9] zram: identify asynchronous IO's return value
Date: Mon, 26 Jun 2017 15:53:04 +0900
Message-ID: <1498459987-24562-7-git-send-email-minchan@kernel.org> (raw)
In-Reply-To: <1498459987-24562-1-git-send-email-minchan@kernel.org>

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 e31fef7..896867e2 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -772,7 +772,7 @@ 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;
 	unsigned long alloced_pages;
 	unsigned long handle = 0;
 	unsigned int comp_len = 0;
@@ -876,7 +876,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 
 	/* Update stats */
 	atomic64_inc(&zram->stats.pages_stored);
-	return 0;
+	return ret;
 }
 
 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
@@ -958,6 +958,11 @@ 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)
 {
@@ -979,7 +984,7 @@ 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
@@ -1072,7 +1077,7 @@ 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;
@@ -1081,7 +1086,7 @@ 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;
 	}
 
@@ -1092,7 +1097,7 @@ 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
@@ -1102,9 +1107,20 @@ 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

  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-26  6:52 [PATCH v1 0/7] writeback incompressible pages to storage Minchan Kim
2017-06-26  6:52 ` [PATCH v1 1/9] zram: clean up duplicated codes in __zram_bvec_write Minchan Kim
2017-06-26  6:53 ` [PATCH v1 2/9] zram: inlining zram_compress Minchan Kim
2017-06-26  6:53 ` [PATCH v1 3/9] zram: rename zram_decompress_page with __zram_bvec_read Minchan Kim
2017-06-26  6:53 ` [PATCH v1 4/9] zram: add interface to specify backing device Minchan Kim
2017-06-26  6:53 ` [PATCH v1 5/9] zram: add free space management in " Minchan Kim
2017-06-26  6:53 ` Minchan Kim [this message]
2017-06-26  6:53 ` [PATCH v1 7/9] zram: write incompressible pages to " Minchan Kim
2017-06-26  6:53 ` [PATCH v1 8/9] zram: read page from " Minchan Kim
2017-06-26  6:53 ` [PATCH v1 9/9] zram: add config and doc file for writeback feature Minchan Kim
2017-06-28 15:41 ` [PATCH v1 0/7] writeback incompressible pages to storage Sergey Senozhatsky
2017-06-29  8:47   ` Minchan Kim
2017-06-29  9:17     ` Sergey Senozhatsky
2017-06-29  9:29       ` Minchan Kim

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1498459987-24562-7-git-send-email-minchan@kernel.org \
    --to=minchan@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=juno.choi@lge.com \
    --cc=kernel-team@lge.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sergey.senozhatsky@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git