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Subject: Re: [PATCH 5/7] hfsplus: stop using ioctl_by_bdev
To:     Christoph Hellwig <hch@lst.de>
Cc:     Tim Waugh <tim@cyberelk.net>, Borislav Petkov <bp@alien8.de>,
        Jan Kara <jack@suse.com>, linux-block@vger.kernel.org,
        linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Damien Le Moal <damien.lemoal@wdc.com>
References: <20200425075706.721917-1-hch@lst.de>
 <20200425075706.721917-6-hch@lst.de>
 <6c47f731-7bff-f186-da55-7ce6cffacdc3@kernel.dk>
 <20200504162114.GA637@lst.de>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <6cbb8166-a419-9322-78ee-51fbec22b59d@kernel.dk>
Date:   Mon, 4 May 2020 10:41:55 -0600
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On 5/4/20 10:21 AM, Christoph Hellwig wrote:
> On Mon, May 04, 2020 at 10:16:40AM -0600, Jens Axboe wrote:
>> On 4/25/20 1:57 AM, Christoph Hellwig wrote:
>>>  	if (HFSPLUS_SB(sb)->session >= 0) {
>>> +		struct cdrom_tocentry te;
>>> +
>>> +		if (!cdi)
>>> +			return -EINVAL;
>>> +
>>>  		te.cdte_track = HFSPLUS_SB(sb)->session;
>>>  		te.cdte_format = CDROM_LBA;
>>> -		res = ioctl_by_bdev(sb->s_bdev,
>>> -			CDROMREADTOCENTRY, (unsigned long)&te);
>>> -		if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
>>> -			*start = (sector_t)te.cdte_addr.lba << 2;
>>> -			return 0;
>>> +		if (cdrom_read_tocentry(cdi, &te) ||
>>> +		    (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) {
>>> +			pr_err("invalid session number or type of track\n");
>>> +			return -EINVAL;
>>>  		}
>>
>> I must be missing something obvious from just looking over the patches,
>> but how does this work if cdrom is modular and hfsplus is builtin?
> 
> In that case disk_to_cdi will return NULL as it uses IS_REACHABLE
> and the file systems won't query the CD-ROM specific information.

Got it, looks like that'll do the trick without nasty Kconfig
dependencies.

-- 
Jens Axboe