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From: Weiping Zhang <zhangweiping@didiglobal.com>
To: <axboe@kernel.dk>, <tj@kernel.org>
Cc: <linux-block@vger.kernel.org>, <cgroups@vger.kernel.org>
Subject: [RFC 1/3] update the real issue size when bio_split
Date: Sat, 21 Mar 2020 09:21:04 +0800
Message-ID: <c35d6607d06b9cdad280f0e0f612e57910bbd4e4.1584728740.git.zhangweiping@didiglobal.com> (raw)
In-Reply-To: <cover.1584728740.git.zhangweiping@didiglobal.com>

The split.bi_iter.bi_size was copied from @bio,
bi_issue was initialized in this flow:
bio_clone_fast->__bio_clone_fast->blkcg_bio_issue_init

So the split->bi_issue has a wrong size, so update the size
at here.

Change-Id: I1f9c8c973ac1d41f4aea17a9a766b4c4d532f642
Signed-off-by: Weiping Zhang <zhangweiping@didiglobal.com>
---
 block/bio.c               | 13 +++++++++++++
 include/linux/blk_types.h |  9 +++++++++
 2 files changed, 22 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index 0985f3422556..8654c4d692e5 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1911,6 +1911,19 @@ struct bio *bio_split(struct bio *bio, int sectors,
 
 	split->bi_iter.bi_size = sectors << 9;
 
+	/*
+	 * reinit bio->bi_issue, the split.bi_iter.bi_size was copied
+	 * from @bio, bi_issue was initialized in this flow:
+	 * bio_clone_fast->__bio_clone_fast->blkcg_bio_issue_init
+	 *
+	 * So the split->bi_issue has a wrong size, so update the size
+	 * at here.
+	 *
+	 * Actually, we can just use blkcg_bio_issue_init, there is just
+	 * a bit difference for the issue_time.
+	 */
+	bio_issue_update_size(&split->bi_issue, bio_sectors(split));
+
 	if (bio_integrity(split))
 		bio_integrity_trim(split);
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 70254ae11769..56e41ef3e827 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -128,6 +128,15 @@ static inline sector_t bio_issue_size(struct bio_issue *issue)
 	return ((issue->value & BIO_ISSUE_SIZE_MASK) >> BIO_ISSUE_SIZE_SHIFT);
 }
 
+static inline void bio_issue_update_size(struct bio_issue *issue, sector_t size)
+{
+	size &= (1ULL << BIO_ISSUE_SIZE_BITS) - 1;
+	/* set all _issue_size bits to 1 */
+	issue->value |= (u64)BIO_ISSUE_SIZE_MASK;
+	/* set new size */
+	issue->value &= ((u64)size << BIO_ISSUE_SIZE_SHIFT);
+}
+
 static inline void bio_issue_init(struct bio_issue *issue,
 				       sector_t size)
 {
-- 
2.18.1


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-21  1:20 [RFC 0/3] blkcg: add blk-iotrack Weiping Zhang
2020-03-21  1:21 ` Weiping Zhang [this message]
2020-03-21  1:21 ` [RFC 2/3] bio: track timestamp of submitting bio the disk driver Weiping Zhang
2020-03-21  1:21 ` [RFC 3/3] blkcg: add blk-iotrack Weiping Zhang
2020-03-24 18:27 ` [RFC 0/3] " Tejun Heo
2020-03-25 12:49   ` Weiping Zhang
2020-03-25 14:12     ` Tejun Heo
2020-03-25 16:45       ` Weiping Zhang
2020-03-26 15:08         ` Weiping Zhang
2020-03-26 16:14           ` Tejun Heo
2020-03-26 16:27             ` Weiping Zhang
2020-03-31 14:19               ` Tejun Heo
2020-03-27  6:27 ` [RFC PATCH v2 " Weiping Zhang

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