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Date:   Tue, 15 May 2018 11:37:20 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     David Miller <davem@davemloft.net>
Cc:     dave@stgolabs.net, akpm@linux-foundation.org, tgraf@suug.ch,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        dbueso@suse.de
Subject: Re: [PATCH] lib/rhashtable: reorder some inititalization sequences
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References: <20180514151332.31352-1-dave@stgolabs.net>
 <20180514.225213.1789810083198383905.davem@davemloft.net>
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On Mon, May 14, 2018 at 10:52:13PM -0400, David Miller wrote:
> From: Davidlohr Bueso <dave@stgolabs.net>
> Date: Mon, 14 May 2018 08:13:32 -0700
> 
> > rhashtable_init() allocates memory at the very end of the
> > call, once everything is setup; with the exception of the
> > nelems parameter. However, unless the user is doing something
> > bogus with params for which -EINVAL is returned, memory
> > allocation is the only operation that can trigger the call
> > to fail.
> > 
> > Thus move bucket_table_alloc() up such that we fail back to
> > the caller asap, instead of doing useless checks. This is
> > safe as the the table allocation isn't using the halfly
> > setup 'ht' structure and bucket_table_alloc() call chain only
> > ends up using the ht->nulls_base member in INIT_RHT_NULLS_HEAD.
> > 
> > Also move the locking initialization down to the end.
> > 
> > Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> 
> The user potentially "doing something bogus" is why the most
> expensive part of the initialization (the memory allocation)
> is done after everything else is validated.
> 
> I think it's best to keep things as-is.

I agree.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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