From: Christoph Hellwig <hch@lst.de> To: Jens Axboe <axboe@kernel.dk>, Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@kernel.org> Cc: Yu Kuai <yukuai1@huaweicloud.com>, dm-devel@redhat.com, linux-block@vger.kernel.org Subject: [PATCH 7/7] block: store the holder kobject in bd_holder_disk Date: Sun, 30 Oct 2022 16:31:19 +0100 [thread overview] Message-ID: <20221030153120.1045101-8-hch@lst.de> (raw) In-Reply-To: <20221030153120.1045101-1-hch@lst.de> We hold a reference to the holder kobject for each bd_holder_disk, so to make the code a bit more robust, use a reference to it instead of the block_device. As long as no one clears ->bd_holder_dir in before freeing the disk, this isn't strictly required, but it does make the code more clear and more robust. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/holder.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/block/holder.c b/block/holder.c index dd9327b43ce05..a8c355b9d0806 100644 --- a/block/holder.c +++ b/block/holder.c @@ -4,7 +4,7 @@ struct bd_holder_disk { struct list_head list; - struct block_device *bdev; + struct kobject *holder_dir; int refcnt; }; @@ -14,7 +14,7 @@ static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, struct bd_holder_disk *holder; list_for_each_entry(holder, &disk->slave_bdevs, list) - if (holder->bdev == bdev) + if (holder->holder_dir == bdev->bd_holder_dir) return holder; return NULL; } @@ -82,27 +82,24 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) } INIT_LIST_HEAD(&holder->list); - holder->bdev = bdev; holder->refcnt = 1; + holder->holder_dir = kobject_get(bdev->bd_holder_dir); + ret = add_symlink(disk->slave_dir, bdev_kobj(bdev)); if (ret) - goto out_free_holder; - ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj); + goto out_put_holder_dir; + ret = add_symlink(holder->holder_dir, &disk_to_dev(disk)->kobj); if (ret) goto out_del_symlink; list_add(&holder->list, &disk->slave_bdevs); - /* - * del_gendisk drops the initial reference to bd_holder_dir, so we need - * to keep our own here to allow for cleanup past that point. - */ - kobject_get(bdev->bd_holder_dir); mutex_unlock(&disk->open_mutex); return 0; out_del_symlink: del_symlink(disk->slave_dir, bdev_kobj(bdev)); -out_free_holder: +out_put_holder_dir: + kobject_put(holder->holder_dir); kfree(holder); out_unlock: mutex_unlock(&disk->open_mutex); @@ -131,8 +128,8 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) holder = bd_find_holder_disk(bdev, disk); if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { del_symlink(disk->slave_dir, bdev_kobj(bdev)); - del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj); - kobject_put(bdev->bd_holder_dir); + del_symlink(holder->holder_dir, &disk_to_dev(disk)->kobj); + kobject_put(holder->holder_dir); list_del_init(&holder->list); kfree(holder); } -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de> To: Jens Axboe <axboe@kernel.dk>, Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@kernel.org> Cc: linux-block@vger.kernel.org, Yu Kuai <yukuai1@huaweicloud.com>, dm-devel@redhat.com Subject: [dm-devel] [PATCH 7/7] block: store the holder kobject in bd_holder_disk Date: Sun, 30 Oct 2022 16:31:19 +0100 [thread overview] Message-ID: <20221030153120.1045101-8-hch@lst.de> (raw) In-Reply-To: <20221030153120.1045101-1-hch@lst.de> We hold a reference to the holder kobject for each bd_holder_disk, so to make the code a bit more robust, use a reference to it instead of the block_device. As long as no one clears ->bd_holder_dir in before freeing the disk, this isn't strictly required, but it does make the code more clear and more robust. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/holder.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/block/holder.c b/block/holder.c index dd9327b43ce05..a8c355b9d0806 100644 --- a/block/holder.c +++ b/block/holder.c @@ -4,7 +4,7 @@ struct bd_holder_disk { struct list_head list; - struct block_device *bdev; + struct kobject *holder_dir; int refcnt; }; @@ -14,7 +14,7 @@ static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, struct bd_holder_disk *holder; list_for_each_entry(holder, &disk->slave_bdevs, list) - if (holder->bdev == bdev) + if (holder->holder_dir == bdev->bd_holder_dir) return holder; return NULL; } @@ -82,27 +82,24 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) } INIT_LIST_HEAD(&holder->list); - holder->bdev = bdev; holder->refcnt = 1; + holder->holder_dir = kobject_get(bdev->bd_holder_dir); + ret = add_symlink(disk->slave_dir, bdev_kobj(bdev)); if (ret) - goto out_free_holder; - ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj); + goto out_put_holder_dir; + ret = add_symlink(holder->holder_dir, &disk_to_dev(disk)->kobj); if (ret) goto out_del_symlink; list_add(&holder->list, &disk->slave_bdevs); - /* - * del_gendisk drops the initial reference to bd_holder_dir, so we need - * to keep our own here to allow for cleanup past that point. - */ - kobject_get(bdev->bd_holder_dir); mutex_unlock(&disk->open_mutex); return 0; out_del_symlink: del_symlink(disk->slave_dir, bdev_kobj(bdev)); -out_free_holder: +out_put_holder_dir: + kobject_put(holder->holder_dir); kfree(holder); out_unlock: mutex_unlock(&disk->open_mutex); @@ -131,8 +128,8 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) holder = bd_find_holder_disk(bdev, disk); if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { del_symlink(disk->slave_dir, bdev_kobj(bdev)); - del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj); - kobject_put(bdev->bd_holder_dir); + del_symlink(holder->holder_dir, &disk_to_dev(disk)->kobj); + kobject_put(holder->holder_dir); list_del_init(&holder->list); kfree(holder); } -- 2.30.2 -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2022-10-30 15:32 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-10-30 15:31 fix delayed holder tracking v2 Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` [PATCH 1/7] block: clear ->slave_dir when dropping the main slave_dir reference Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` [PATCH 2/7] dm: remove free_table_devices Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` [PATCH 3/7] dm: cleanup open_table_device Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` [PATCH 4/7] dm: cleanup close_table_device Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` [PATCH 5/7] dm: track per-add_disk holder relations in DM Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-11-09 2:08 ` Yu Kuai 2022-11-09 2:08 ` [dm-devel] " Yu Kuai 2022-11-09 8:26 ` Christoph Hellwig 2022-11-09 8:26 ` [dm-devel] " Christoph Hellwig 2022-11-10 18:09 ` Mike Snitzer 2022-11-10 18:09 ` [dm-devel] " Mike Snitzer 2022-11-10 19:48 ` Mike Snitzer 2022-11-10 19:48 ` Mike Snitzer 2022-11-12 6:23 ` Yu Kuai 2022-11-12 6:23 ` [dm-devel] " Yu Kuai 2022-10-30 15:31 ` [PATCH 6/7] block: remove delayed holder registration Christoph Hellwig 2022-10-30 15:31 ` [dm-devel] " Christoph Hellwig 2022-10-30 15:31 ` Christoph Hellwig [this message] 2022-10-30 15:31 ` [dm-devel] [PATCH 7/7] block: store the holder kobject in bd_holder_disk Christoph Hellwig 2022-10-31 1:52 ` Yu Kuai 2022-10-31 1:52 ` [dm-devel] " Yu Kuai 2022-11-01 10:49 ` Christoph Hellwig 2022-11-01 10:49 ` [dm-devel] " Christoph Hellwig 2022-11-01 11:12 ` Yu Kuai 2022-11-01 11:12 ` [dm-devel] " Yu Kuai 2022-11-01 11:21 ` Christoph Hellwig 2022-11-01 11:21 ` [dm-devel] " Christoph Hellwig 2022-11-01 11:28 ` Yu Kuai 2022-11-01 11:28 ` [dm-devel] " Yu Kuai 2022-11-01 13:18 ` Christoph Hellwig 2022-11-01 13:18 ` [dm-devel] " Christoph Hellwig 2022-11-01 13:29 ` Yu Kuai 2022-11-01 13:29 ` [dm-devel] " Yu Kuai
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