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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>, Coly Li <colyli@suse.de>,
	Song Liu <song@kernel.org>,
	dm-devel@redhat.com, linux-bcache@vger.kernel.org,
	linux-raid@vger.kernel.org, linux-s390@vger.kernel.org,
	linux-block@vger.kernel.org
Subject: [PATCH 05/10] block: do not reassig ->bi_bdev when partition remapping
Date: Sun, 24 Jan 2021 11:02:36 +0100
Message-ID: <20210124100241.1167849-6-hch@lst.de> (raw)
In-Reply-To: <20210124100241.1167849-1-hch@lst.de>

There is no good reason to reassign ->bi_bdev when remapping the
partition-relative block number to the device wide one, as all the
information required by the drivers comes from the gendisk anyway.

Keeping the original ->bi_bdev alive will allow to greatly simplify
the partition-away I/O accounting.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
---
 block/blk-core.c          | 5 +++--
 include/linux/bio.h       | 2 ++
 include/linux/blk_types.h | 1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 64f69022de9627..1c1b97a82caa2e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -752,7 +752,7 @@ static int blk_partition_remap(struct bio *bio)
 				      bio->bi_iter.bi_sector -
 				      p->bd_start_sect);
 	}
-	bio->bi_bdev = bdev_whole(p);
+	bio_set_flag(bio, BIO_REMAPPED);
 	return 0;
 }
 
@@ -817,7 +817,8 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
 		goto end_io;
 	if (unlikely(bio_check_eod(bio)))
 		goto end_io;
-	if (bio->bi_bdev->bd_partno && unlikely(blk_partition_remap(bio)))
+	if (bio->bi_bdev->bd_partno && !bio_flagged(bio, BIO_REMAPPED) &&
+	    unlikely(blk_partition_remap(bio)))
 		goto end_io;
 
 	/*
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 12af7aa5db3778..2f1155eabaff29 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -485,6 +485,7 @@ extern const char *bio_devname(struct bio *bio, char *buffer);
 
 #define bio_set_dev(bio, bdev) 				\
 do {							\
+	bio_clear_flag(bio, BIO_REMAPPED);		\
 	if ((bio)->bi_bdev != (bdev))			\
 		bio_clear_flag(bio, BIO_THROTTLED);	\
 	(bio)->bi_bdev = (bdev);			\
@@ -493,6 +494,7 @@ do {							\
 
 #define bio_copy_dev(dst, src)			\
 do {						\
+	bio_clear_flag(dst, BIO_REMAPPED);		\
 	(dst)->bi_bdev = (src)->bi_bdev;	\
 	bio_clone_blkg_association(dst, src);	\
 } while (0)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 8ebd8be3e05082..1bc6f6a01070fc 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -303,6 +303,7 @@ enum {
 				 * of this bio. */
 	BIO_CGROUP_ACCT,	/* has been accounted to a cgroup */
 	BIO_TRACKED,		/* set if bio goes through the rq_qos path */
+	BIO_REMAPPED,
 	BIO_FLAG_LAST
 };
 
-- 
2.29.2


  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-24 10:02 store a pointer to the block_device in struct bio (again) v2 Christoph Hellwig
2021-01-24 10:02 ` [PATCH 01/10] brd: remove the end of device check in brd_do_bvec Christoph Hellwig
2021-01-25 13:51   ` Johannes Thumshirn
2021-01-24 10:02 ` [PATCH 02/10] dcssblk: remove the end of device check in dcssblk_submit_bio Christoph Hellwig
2021-01-25 13:52   ` Johannes Thumshirn
2021-01-24 10:02 ` [PATCH 03/10] block: store a block_device pointer in struct bio Christoph Hellwig
2021-01-24 10:02 ` [PATCH 04/10] block: simplify submit_bio_checks a bit Christoph Hellwig
2021-01-25 14:02   ` Johannes Thumshirn
2021-01-24 10:02 ` Christoph Hellwig [this message]
2021-01-25 17:53   ` [PATCH 05/10] block: do not reassig ->bi_bdev when partition remapping Jens Axboe
2021-01-25 17:55     ` Christoph Hellwig
     [not found]       ` <2b600368-96fa-7caf-f05b-321de616f7c9@kernel.dk>
2021-01-25 18:03         ` Jens Axboe
2021-01-25 18:13           ` Christoph Hellwig
2021-01-25 18:15             ` Jens Axboe
2021-01-25 18:18               ` Christoph Hellwig
2021-01-25 18:19                 ` Jens Axboe
2021-01-25 18:21                   ` Christoph Hellwig
2021-01-25 18:31                     ` Jens Axboe
2021-01-24 10:02 ` [PATCH 06/10] block: use ->bi_bdev for bio based I/O accounting Christoph Hellwig
2021-01-24 10:02 ` [PATCH 07/10] blk-mq: use ->bi_bdev for " Christoph Hellwig
2021-01-24 10:02 ` [PATCH 08/10] block: add a disk_uevent helper Christoph Hellwig
2021-01-25 14:14   ` Johannes Thumshirn
2021-01-24 10:02 ` [PATCH 09/10] block: remove DISK_PITER_REVERSE Christoph Hellwig
2021-01-24 10:02 ` [PATCH 10/10] block: use an xarray for disk->part_tbl Christoph Hellwig
2021-01-25 16:24 ` store a pointer to the block_device in struct bio (again) v2 Jens Axboe

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