linux-kernel - [PATCH] block: check disk flag before setting scan bit

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Message-Id: <20230117075329.14968-1-wangjie2011cs@163.com>
Date:   Tue, 17 Jan 2023 15:53:29 +0800
From:   Jie Wang <wangjie2011cs@....com>
To:     axboe@...nel.dk
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        wangjie2011cs@....com
Subject: [PATCH] block: check disk flag before setting scan bit

No need to scan partitions for disk who has set flag GENHD_FL_NO_PART in
driver code. In disk_scan_partitions function, the same checking is
existing, so we believe this change is reasonable.

In our case, some virtual block devices are not managed by GPT, then scan
partition operation is not a must. So we set GENHD_FL_NO_PART flag in
driver intended to avoid partitions being dropped/added.
But GD_NEED_PART_SCAN bit was still set by bdev_check_media_change, which
causing problems here.

Signed-off-by: Jie Wang <wangjie2011cs@....com>
---
 block/disk-events.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/disk-events.c b/block/disk-events.c
index aee25a7e1ab7..68d911135bc7 100644
--- a/block/disk-events.c
+++ b/block/disk-events.c
@@ -284,7 +284,8 @@ bool bdev_check_media_change(struct block_device *bdev)
 	if (__invalidate_device(bdev, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			bdev->bd_disk->disk_name);
-	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
+	if (!(bdev->bd_disk->flags & GENHD_FL_NO_PART))
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	return true;
 }
 EXPORT_SYMBOL(bdev_check_media_change);
@@ -310,7 +311,8 @@ bool disk_force_media_change(struct gendisk *disk, unsigned int events)
 	if (__invalidate_device(disk->part0, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			disk->disk_name);
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
+	if (!(bdev->bd_disk->flags & GENHD_FL_NO_PART))
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
 	return true;
 }
 EXPORT_SYMBOL_GPL(disk_force_media_change);
-- 
2.17.1