linux-kernel - Re: [PATCH 4/7] cdrom: factor out a cdrom

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Date:   Thu, 23 Apr 2020 07:41:39 +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 4/7] cdrom: factor out a cdrom_multisession helper

On 2020/04/23 16:15, Christoph Hellwig wrote:
> Factor out a version of the CDROMMULTISESSION: ioctl handler that can
> be called directly from kernel space.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  drivers/cdrom/cdrom.c | 41 +++++++++++++++++++++++++----------------
>  include/linux/cdrom.h |  2 ++
>  2 files changed, 27 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
> index c91d1e138214..06896c07b133 100644
> --- a/drivers/cdrom/cdrom.c
> +++ b/drivers/cdrom/cdrom.c
> @@ -2295,37 +2295,46 @@ static int cdrom_read_cdda(struct cdrom_device_info *cdi, __u8 __user *ubuf,
>  	return cdrom_read_cdda_old(cdi, ubuf, lba, nframes);	
>  }
>  
> -static int cdrom_ioctl_multisession(struct cdrom_device_info *cdi,
> -		void __user *argp)
> +int cdrom_multisession(struct cdrom_device_info *cdi,
> +		struct cdrom_multisession *info)
>  {
> -	struct cdrom_multisession ms_info;
>  	u8 requested_format;
>  	int ret;
>  
> -	cd_dbg(CD_DO_IOCTL, "entering CDROMMULTISESSION\n");
> -
>  	if (!(cdi->ops->capability & CDC_MULTI_SESSION))
>  		return -ENOSYS;
>  
> -	if (copy_from_user(&ms_info, argp, sizeof(ms_info)))
> -		return -EFAULT;
> -
> -	requested_format = ms_info.addr_format;
> +	requested_format = info->addr_format;
>  	if (requested_format != CDROM_MSF && requested_format != CDROM_LBA)
>  		return -EINVAL;
> -	ms_info.addr_format = CDROM_LBA;
> +	info->addr_format = CDROM_LBA;
>  
> -	ret = cdi->ops->get_last_session(cdi, &ms_info);
> -	if (ret)
> -		return ret;
> +	ret = cdi->ops->get_last_session(cdi, info);
> +	if (!ret)
> +		sanitize_format(&info->addr, &info->addr_format,
> +				requested_format);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(cdrom_multisession);
>  
> -	sanitize_format(&ms_info.addr, &ms_info.addr_format, requested_format);
> +static int cdrom_ioctl_multisession(struct cdrom_device_info *cdi,
> +		void __user *argp)
> +{
> +	struct cdrom_multisession info;
> +	int ret;
> +
> +	cd_dbg(CD_DO_IOCTL, "entering CDROMMULTISESSION\n");
>  
> -	if (copy_to_user(argp, &ms_info, sizeof(ms_info)))
> +	if (copy_from_user(&info, argp, sizeof(info)))
> +		return -EFAULT;
> +	ret = cdrom_multisession(cdi, &info);
> +	if (ret)
> +		return ret;
> +	if (copy_to_user(argp, &info, sizeof(info)))
>  		return -EFAULT;
>  
>  	cd_dbg(CD_DO_IOCTL, "CDROMMULTISESSION successful\n");
> -	return 0;
> +	return ret;
>  }
>  
>  static int cdrom_ioctl_eject(struct cdrom_device_info *cdi)
> diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
> index 008c4d79fa33..8543fa59da72 100644
> --- a/include/linux/cdrom.h
> +++ b/include/linux/cdrom.h
> @@ -94,6 +94,8 @@ struct cdrom_device_ops {
>  			       struct packet_command *);
>  };
>  
> +int cdrom_multisession(struct cdrom_device_info *cdi,
> +		struct cdrom_multisession *info);
>  int cdrom_read_tocentry(struct cdrom_device_info *cdi,
>  		struct cdrom_tocentry *entry);
>  
> 

Looks OK to me.

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

-- 
Damien Le Moal
Western Digital Research