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Subject: Re: [PATCH] scsi: sd: call device_del() if device_add_disk() fails
From:   James Bottomley <jejb@linux.ibm.com>
Reply-To: jejb@linux.ibm.com
To:     Dan Carpenter <dan.carpenter@oracle.com>,
        Wenchao Hao <haowenchao@huawei.com>,
        syzkaller-bugs@googlegroups.com
Cc:     fmdefrancesco@gmail.com, axboe@kernel.dk,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
        syzbot+f08c77040fa163a75a46@syzkaller.appspotmail.com,
        linfeilong@huawei.com
Date:   Thu, 31 Mar 2022 10:19:57 -0400
In-Reply-To: <20220331134210.GF12805@kadam>
References: <20220329154948.10350-1-fmdefrancesco@gmail.com>
         <20220331152622.616534-1-haowenchao@huawei.com>
         <20220331054156.GI3293@kadam>
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On Thu, 2022-03-31 at 16:42 +0300, Dan Carpenter wrote:
[...]
> Also, I don't really understand why we don't have to call
> put_device(&sdkp->disk_dev) at the end of sd_remove().

That's because the final put is done by the gendisk ->free_disk()
function which is scsi_disk_free_disk().  Most of the gendisk functions
we provide convert a gendisk to a scsi_disk (via the gendisk
private_data), so the sdkp has to live as long as the gendisk.

James