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Message-ID: <93834519-c945-94a7-f1f8-7bf85bf86dd5@acm.org>
Date:   Wed, 21 Jun 2023 08:47:10 -0700
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Subject: Re: [PATCH] scsi/sg: don't grab scsi host module reference
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To:     Yu Kuai <yukuai1@huaweicloud.com>, hch@lst.de,
        chaitanyak@nvidia.com, shinichiro.kawasaki@wdc.com,
        dgilbert@interlog.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com, yukuai3@huawei.com, axboe@kernel.dk
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        yi.zhang@huawei.com, yangerkun@huawei.com
References: <20230621160111.1433521-1-yukuai1@huaweicloud.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20230621160111.1433521-1-yukuai1@huaweicloud.com>
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On 6/21/23 09:01, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> In order to prevent request_queue to be freed before cleaning up
> blktrace debugfs entries, commit db59133e9279 ("scsi: sg: fix blktrace
> debugfs entries leakage") use scsi_device_get(), however,
> scsi_device_get() will also grab scsi module reference and scsi module
> can't be removed.
> 
> It's reported that blktests can't unload scsi_debug after block/001:
> 
> blktests (master) # ./check block
> block/001 (stress device hotplugging) [failed]
>       +++ /root/blktests/results/nodev/block/001.out.bad 2023-06-19
>        Running block/001
>        Stressing sd
>       +modprobe: FATAL: Module scsi_debug is in use.
> 
> Fix this problem by grabbing request_queue reference directly, so that
> scsi host module can still be unloaded while request_queue will be
> pinged by sg device.

pinged -> pinned

Otherwise this patch looks good to me.

Bart.