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 769F0C433EF for ; Sat, 12 Feb 2022 00:29:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354437AbiBLA3O (ORCPT ); Fri, 11 Feb 2022 19:29:14 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:32924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344273AbiBLA3L (ORCPT ); Fri, 11 Feb 2022 19:29:11 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBD8BD7E for ; Fri, 11 Feb 2022 16:29:08 -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 68CCB61CB4 for ; Sat, 12 Feb 2022 00:29:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79A56C340E9; Sat, 12 Feb 2022 00:29:07 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="PJgyFx1J" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1644625745; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=JGlj9xKTqCKUDSazvzHm7AoG8NZOUjaUCMMHExPBXO8=; b=PJgyFx1JdU0HL7IYQ2dKvRLMCfiXWZ7qA7ADHlUmgkcsr0NiaNVDxJy+4KzK5/RFHMMPJH BNKggONT2rtMFkVGgnwIFGKBugKpjimSOci8ZmoS+G0gUP2tWaCUxan1I6m2MG1ZC4bVh5 Ozjl1+3pOvkTTMkW8bm/FPxX1JK162g= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 5e080588 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Sat, 12 Feb 2022 00:29:05 +0000 (UTC) From: "Jason A. Donenfeld" To: linux@dominikbrodowski.net, linux-kernel@vger.kernel.org Cc: "Jason A. Donenfeld" Subject: [PATCH] random: do not take pool spinlock at boot Date: Sat, 12 Feb 2022 01:28:59 +0100 Message-Id: <20220212002859.622233-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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