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Date: Thu, 15 May 2008 02:46:00 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Harvey Harrison <harvey.harrison@gmail.com>,
       David Woodhouse <dwmw2@infradead.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mtd: mtdchar.c silence sparse warning
Message-ID: <20080515014600.GR13907@ZenIV.linux.org.uk>
References: <1210814530.6191.52.camel@brick> <20080514183837.460ba848.akpm@linux-foundation.org>
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On Wed, May 14, 2008 at 06:38:37PM -0700, Andrew Morton wrote:
> > -		if (copy_to_user(&((struct mtd_oob_buf *)argp)->length,
> > +		if (copy_to_user(argp + offsetof(struct mtd_oob_buf, length),
> >  				 &retlen, sizeof(buf.length)))
> >  			ret = -EFAULT;
> 
> Cleaner would be:
> 
> 	struct mtd_oob_buf __user *user_mtd_oob_buf = argp;
> 
> 	if (copy_to_user(&user_mtd_oob_buf->length, ...

Yup.  BTW, &((type __user *)p)->field) would work just fine too, but yeah,
local variable like that would be cleaner.