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Date: Thu, 26 Nov 2020 10:59:48 +0100
From: Christoph Hellwig <hch@lst.de>
To: Minchan Kim <minchan@kernel.org>
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Cc: Justin Sanders <justin@coraid.com>, Mike Snitzer <snitzer@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>, linux-nvme@lists.infradead.org,
	Song Liu <song@kernel.org>, dm-devel@redhat.com,
	Christoph Hellwig <hch@lst.de>, drbd-dev@lists.linbit.com,
	linux-scsi@vger.kernel.org, xen-devel@lists.xenproject.org,
	Ilya Dryomov <idryomov@gmail.com>, Jack Wang <jinpu.wang@cloud.ionos.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Josef Bacik <josef@toxicpanda.com>, nbd@other.debian.org,
	linux-raid@vger.kernel.org, Stefan Hajnoczi <stefanha@redhat.com>,
	ceph-devel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	linux-fsdevel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Roger Pau =?iso-8859-1?Q?Monn=E9?= <roger.pau@citrix.com>
Subject: Re: [Drbd-dev] [PATCH 60/78] zram: remove the claim mechanism
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On Wed, Nov 25, 2020 at 05:11:07PM -0800, Minchan Kim wrote:
> With this patch, how deal with the race?
> 
> CPU 1                                     CPU 2
> 
> hot_remove_store
>   zram_remove
>     zram_busy
>       return -EBUSY
>                                          open /dev/zram0
>     del_gendisk
>     zram_reset and destroy

Yeah, it looks like zram does not really handle hot unplugging unlike
other drivers.  So I've dropped this one for now.