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From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org
Subject: Re: [PATCH 1/2] block: grab a device refcount in disk_uevent
Date: Thu, 1 Jul 2021 16:54:05 +0800	[thread overview]
Message-ID: <YN2CrbtFEKwDGff0@T590> (raw)
In-Reply-To: <20210701081638.246552-2-hch@lst.de>

On Thu, Jul 01, 2021 at 10:16:37AM +0200, Christoph Hellwig wrote:
> Sending uevents requires the struct device to be alive.  To
> ensure that grab the device refcount instead of just an inode
> reference.
> 
> Fixes: bc359d03c7ec ("block: add a disk_uevent helper")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/genhd.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 79aa40b4c39c..af4d2ab4a633 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -365,12 +365,12 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action)
>  	xa_for_each(&disk->part_tbl, idx, part) {
>  		if (bdev_is_partition(part) && !bdev_nr_sectors(part))
>  			continue;
> -		if (!bdgrab(part))
> +		if (!kobject_get_unless_zero(&part->bd_device.kobj))
>  			continue;

->bd_device is embedded in the block device, and it has same lifetime
with the block device, even part_release() calls bdput() to release this
device, so why doesn't work by holding a inode reference?


Thanks,
Ming


  reply	other threads:[~2021-07-01  8:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-01  8:16 two fixup for the block_device / hd_struct merge Christoph Hellwig
2021-07-01  8:16 ` [PATCH 1/2] block: grab a device refcount in disk_uevent Christoph Hellwig
2021-07-01  8:54   ` Ming Lei [this message]
2021-07-01  9:02     ` Christoph Hellwig
2021-07-01  9:17       ` Ming Lei
2021-07-01  9:27         ` Ming Lei
2021-07-01  9:49           ` Christoph Hellwig
2021-07-01  8:16 ` [PATCH 2/2] block: remove the bdgrab in blk_drop_partitions Christoph Hellwig
2021-07-01 16:21 ` two fixup for the block_device / hd_struct merge Jens Axboe

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