From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Date: Mon, 11 Jan 2016 22:51:05 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: chengang@emindsoft.com.cn
Cc: dhowells@redhat.com, akpm@linux-foundation.org,
	nicolas.iooss_linux@m4x.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, Chen Gang <gang.chen.5i5j@gmail.com>
Subject: Re: [PATCH] fs: dcache: Use bool return value instead of int
Message-ID: <20160111225104.GO17997@ZenIV.linux.org.uk>
References: <1452547845-12039-1-git-send-email-chengang@emindsoft.com.cn>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1452547845-12039-1-git-send-email-chengang@emindsoft.com.cn>
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

On Tue, Jan 12, 2016 at 05:30:45AM +0800, chengang@emindsoft.com.cn wrote:
> From: Chen Gang <gang.chen.5i5j@gmail.com>
> 
> Use bool type for all functions which return boolean value. It will not
> only let code clearer, but also sometimes let gcc produce better code.

What's the point of this chunk?

>  static enum d_walk_ret check_mount(void *data, struct dentry *dentry)
>  {
> -	int *ret = data;
> +	bool *ret = data;
>  	if (d_mountpoint(dentry)) {
> -		*ret = 1;
> +		*ret = true;
>  		return D_WALK_QUIT;
>  	}
>  	return D_WALK_CONTINUE;

You are replacing a 1-word store with 1-byte store; if anything, that's more
likely to yield _worse_ code, not better one.

> -static inline int d_unhashed(const struct dentry *dentry)
> +static inline bool d_unhashed(const struct dentry *dentry)
>  {
>  	return hlist_bl_unhashed(&dentry->d_hash);
>  }
>  
> -static inline int d_unlinked(const struct dentry *dentry)
> +static inline bool d_unlinked(const struct dentry *dentry)
>  {
>  	return d_unhashed(dentry) && !IS_ROOT(dentry);
>  }

> -static inline int simple_positive(struct dentry *dentry)
> +static inline bool simple_positive(struct dentry *dentry)
>  {
>  	return d_really_is_positive(dentry) && !d_unhashed(dentry);
>  }

And these three are harmless, but completely pointless...