linux-kernel - Re: [RFC][PATCH] kmemdup_from

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Date:	Fri,  6 Mar 2009 18:09:00 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Alexey Dobriyan <adobriyan@...il.com>
Cc:	kosaki.motohiro@...fujitsu.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Li Zefan <lizf@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [RFC][PATCH] kmemdup_from_user(): introduce

> On Fri, Mar 06, 2009 at 12:39:00AM -0800, Andrew Morton wrote:
> > On Fri, 06 Mar 2009 16:27:53 +0800 Li Zefan <lizf@...fujitsu.com> wrote:
> > 
> > > > Let's not add wrapper for every two lines that happen to be used
> > > > together.
> > > > 
> > > 
> > > Why not if we have good reasons? And I don't think we can call this
> > > "happen to" if there are 250+ of them?
> > 
> > The change is a good one.  If a reviewer (me) sees it then you know the
> > code's all right and the review effort becomes less - all you need to check
> > is that the call site is using IS_ERR/PTR_ERR and isn't testing for
> > NULL.  Less code, less chance for bugs.
> > 
> > Plus it makes kernel text smaller.
> > 
> > Yes, the name is a bit cumbersome.
> 
> Some do NUL-termination afterwards and allocate "len + 1", but copy "len".
> Some don't care.

if subsystem want string data, it should use strndup_user().
memdump don't need to care NUL-termination

In addition, also I often review various mm code and patch, I also like
this change.



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