From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87708C433F5 for ; Mon, 21 Feb 2022 05:35:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344552AbiBUFfZ (ORCPT ); Mon, 21 Feb 2022 00:35:25 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:45348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344545AbiBUFfX (ORCPT ); Mon, 21 Feb 2022 00:35:23 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E33E4AE1A for ; Sun, 20 Feb 2022 21:34:58 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 39807611EE for ; Mon, 21 Feb 2022 05:34:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D624C340E9; Mon, 21 Feb 2022 05:34:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645421697; bh=VBlEvlHOLGTDybZZzMukE+NhuuRSv6OX0PR8ydFljic=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EJ6WZmhiUMixrg2XcvhdSFs5piFazAVog70zlNWSvSPA9nuHByxBevdFvAmztuie/ TXXQOZRDcrFUcuPJvrubIeENCGtia1vlIjITwXF7/m5dClrhxnq0fKbFvCD1VIuZ6o 5MlgH2kbYOvHrk9Uuvp6Sf1kb+osVQVCORugiEw8VfDWSu+NGulepuqmUeKWrufxAs LtOEsyLnNP2vUnQ3RMYnYnZzzSHs8IC/lxYD7CAR9R0La8T88iVOyaIqtwtmjXXDPU dNy7RIH9CtwuIj9Z/sGPCBx/2QqZB1xjWKyaezU06/xafclUKyRvfnIHBC/GEFpwny t4M/un8LwrJ7A== Date: Sun, 20 Feb 2022 21:34:56 -0800 From: Eric Biggers To: "Jason A. Donenfeld" Cc: linux@dominikbrodowski.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] random: do not take pool spinlock at boot Message-ID: References: <20220212002859.622233-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220212002859.622233-1-Jason@zx2c4.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 12, 2022 at 01:28:59AM +0100, Jason A. Donenfeld wrote: > Since rand_initialize() is run while interrupts are still off and > nothing else is running, we don't need to repeatedly take and release > the pool spinlock, especially in the RDSEED loop. > > Cc: Dominik Brodowski > Signed-off-by: Jason A. Donenfeld > --- > Dominik - I'm still a bit unclear about early boot semantics that you > seem to know well. Is this patch correct? > > drivers/char/random.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/random.c b/drivers/char/random.c > index d4b692c9de68..8088348190e6 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -966,10 +966,10 @@ int __init rand_initialize(void) > rv = random_get_entropy(); > arch_init = false; > } > - mix_pool_bytes(&rv, sizeof(rv)); > + _mix_pool_bytes(&rv, sizeof(rv)); > } > - mix_pool_bytes(&now, sizeof(now)); > - mix_pool_bytes(utsname(), sizeof(*(utsname()))); > + _mix_pool_bytes(&now, sizeof(now)); > + _mix_pool_bytes(utsname(), sizeof(*(utsname()))); > > extract_entropy(base_crng.key, sizeof(base_crng.key)); > ++base_crng.generation; > -- > 2.35.0 Reviewed-by: Eric Biggers - Eric