Re: [RFC][PATCH] kmemdup_from_user(): introduce

From: KOSAKI Motohiro
Date: Fri Mar 06 2009 - 04:09:21 EST


> 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@xxxxxxxxxxxxxx> 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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