Re: [RFC PATCH V2 05/12] fs: remove unneeded IS_DAX() check

From: Jan Kara <jack@suse.cz>
To: ira.weiny@intel.com
Cc: linux-kernel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>,
	Christoph Hellwig <hch@lst.de>,
	"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
	linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH V2 05/12] fs: remove unneeded IS_DAX() check
Date: Thu, 16 Jan 2020 10:38:07 +0100	[thread overview]
Message-ID: <20200116093807.GB8446@quack2.suse.cz> (raw)
In-Reply-To: <20200110192942.25021-6-ira.weiny@intel.com>

On Fri 10-01-20 11:29:35, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> The IS_DAX() check in io_is_direct() causes a race between changing the
> DAX mode and creating the iocb flags.
> 
> Remove the check because DAX now emulates the page cache API and
> therefore it does not matter if the file mode is DAX or not when the
> iocb flags are created.
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  include/linux/fs.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index d7584bcef5d3..e11989502eac 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3365,7 +3365,7 @@ extern int file_update_time(struct file *file);
>  
>  static inline bool io_is_direct(struct file *filp)
>  {
> -	return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
> +	return (filp->f_flags & O_DIRECT);
>  }
>  
>  static inline bool vma_is_dax(struct vm_area_struct *vma)
> -- 
> 2.21.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR