linux-kernel - Re: [PATCH] fs: Eliminate a local variable to make the code more clear

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Message-ID: <20200908231156.GA23779@haolee.github.io>
Date:   Tue, 8 Sep 2020 23:11:56 +0000
From:   Hao Lee <haolee.swjtu@...il.com>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs: Eliminate a local variable to make the code more
 clear

On Tue, Sep 08, 2020 at 07:48:57PM +0100, Al Viro wrote:
> On Tue, Sep 08, 2020 at 01:06:56PM +0000, Hao Lee wrote:
> > ping
> > 
> > On Wed, Jul 29, 2020 at 03:21:28PM +0000, Hao Lee wrote:
> > > The dentry local variable is introduced in 'commit 84d17192d2afd ("get
> > > rid of full-hash scan on detaching vfsmounts")' to reduce the length of
> > > some long statements for example
> > > mutex_lock(&path->dentry->d_inode->i_mutex). We have already used
> > > inode_lock(dentry->d_inode) to do the same thing now, and its length is
> > > acceptable. Furthermore, it seems not concise that assign path->dentry
> > > to local variable dentry in the statement before goto. So, this function
> > > would be more clear if we eliminate the local variable dentry.
> 
> How does it make the function more clear?  More specifically, what
> analysis of behaviour is simplified by that?

When I first read this function, it takes me a few seconds to think
about if the local variable dentry is always equal to path->dentry and
want to know if it has special purpose. This local variable may confuse
other people too, so I think it would be better to eliminate it.

Thanks,
Hao Lee