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 1C09FC433F5 for ; Fri, 13 May 2022 06:26:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377335AbiEMG03 (ORCPT ); Fri, 13 May 2022 02:26:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377304AbiEMG0U (ORCPT ); Fri, 13 May 2022 02:26:20 -0400 Received: from isilmar-4.linta.de (isilmar-4.linta.de [136.243.71.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1FB02A732 for ; Thu, 12 May 2022 23:26:08 -0700 (PDT) X-isilmar-external: YES X-isilmar-external: YES Received: from owl.dominikbrodowski.net (owl.brodo.linta [10.2.0.111]) by isilmar-4.linta.de (Postfix) with ESMTPSA id A81632013E2; Fri, 13 May 2022 06:26:05 +0000 (UTC) Received: by owl.dominikbrodowski.net (Postfix, from userid 1000) id 903E9809CD; Fri, 13 May 2022 08:24:19 +0200 (CEST) Date: Fri, 13 May 2022 08:24:19 +0200 From: Dominik Brodowski To: "Jason A. Donenfeld" Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] random: move initialization out of reseeding hot path Message-ID: References: <20220509121409.529788-1-Jason@zx2c4.com> <20220509121409.529788-2-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220509121409.529788-2-Jason@zx2c4.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Mon, May 09, 2022 at 02:14:09PM +0200 schrieb Jason A. Donenfeld: > Initialization happens once -- by way of credit_init_bits() -- and then > it never happens again. Therefore, it doesn't need to be in > crng_reseed(), which is a hot path that is called multiple times. It > also doesn't make sense to have there, as initialization activity is > better associated with initialization routines. > > After the prior commit, crng_reseed() now won't be called by multiple > concurrent callers, which means that we can safely move the > "finialize_init" logic into crng_init_bits() unconditionally. > > Cc: Dominik Brodowski > Signed-off-by: Jason A. Donenfeld > --- > drivers/char/random.c | 43 +++++++++++++++++++------------------------ > 1 file changed, 19 insertions(+), 24 deletions(-) > > diff --git a/drivers/char/random.c b/drivers/char/random.c > index 79409cf27a25..1598bb40376e 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -266,7 +266,6 @@ static void crng_reseed(void) > unsigned long flags; > unsigned long next_gen; > u8 key[CHACHA_KEY_SIZE]; > - bool finalize_init = false; > > extract_entropy(key, sizeof(key)); > > @@ -283,28 +282,9 @@ static void crng_reseed(void) > ++next_gen; > WRITE_ONCE(base_crng.generation, next_gen); > WRITE_ONCE(base_crng.birth, jiffies); > - if (!crng_ready()) { > - crng_init = CRNG_READY; > - finalize_init = true; > - } > + crng_init = CRNG_READY; Why unconditionally (you revert that bit in the static branch patch and make it conditional again; so I see no reason for that here)? Otherwise, looks good: Reviewed-by: Dominik Brodowski Thanks, Dominik