linux-kernel - Re: [PATCH 7/7] udf: stop using ioctl_by

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Date:   Thu, 23 Apr 2020 07:43:03 +0000
From:   Damien Le Moal <Damien.LeMoal@....com>
To:     Christoph Hellwig <hch@....de>, Jens Axboe <axboe@...nel.dk>
CC:     Tim Waugh <tim@...erelk.net>, Borislav Petkov <bp@...en8.de>,
        Jan Kara <jack@...e.com>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "linux-ide@...r.kernel.org" <linux-ide@...r.kernel.org>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/7] udf: stop using ioctl_by_bdev

On 2020/04/23 16:15, Christoph Hellwig wrote:
> Instead just call the CD-ROM layer functionality directly.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  fs/udf/lowlevel.c | 29 +++++++++++++----------------
>  1 file changed, 13 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/udf/lowlevel.c b/fs/udf/lowlevel.c
> index 5c7ec121990d..f1094cdcd6cd 100644
> --- a/fs/udf/lowlevel.c
> +++ b/fs/udf/lowlevel.c
> @@ -27,41 +27,38 @@
>  
>  unsigned int udf_get_last_session(struct super_block *sb)
>  {
> +	struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
>  	struct cdrom_multisession ms_info;
> -	unsigned int vol_desc_start;
> -	struct block_device *bdev = sb->s_bdev;
> -	int i;
>  
> -	vol_desc_start = 0;
> -	ms_info.addr_format = CDROM_LBA;
> -	i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
> +	if (!cdi) {
> +		udf_debug("CDROMMULTISESSION not supported.\n");
> +		return 0;
> +	}
>  
> -	if (i == 0) {
> +	ms_info.addr_format = CDROM_LBA;
> +	if (cdrom_multisession(cdi, &ms_info) == 0) {
>  		udf_debug("XA disk: %s, vol_desc_start=%d\n",
>  			  ms_info.xa_flag ? "yes" : "no", ms_info.addr.lba);
>  		if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
> -			vol_desc_start = ms_info.addr.lba;
> -	} else {
> -		udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
> +			return ms_info.addr.lba;
>  	}
> -	return vol_desc_start;
> +	return 0;
>  }
>  
>  unsigned long udf_get_last_block(struct super_block *sb)
>  {
>  	struct block_device *bdev = sb->s_bdev;
> +	struct cdrom_device_info *cdi = disk_to_cdi(bdev->bd_disk);
>  	unsigned long lblock = 0;
>  
>  	/*
> -	 * ioctl failed or returned obviously bogus value?
> +	 * The cdrom layer call failed or returned obviously bogus value?
>  	 * Try using the device size...
>  	 */
> -	if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
> -	    lblock == 0)
> +	if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0)
>  		lblock = i_size_read(bdev->bd_inode) >> sb->s_blocksize_bits;
>  
>  	if (lblock)
>  		return lblock - 1;
> -	else
> -		return 0;
> +	return 0;
>  }
> 

Looks OK to me.

Reviewed-by: Damien Le Moal <damien.lemoal@....com>

-- 
Damien Le Moal
Western Digital Research