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 04038C43334 for ; Thu, 23 Jun 2022 16:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231620AbiFWQqD (ORCPT ); Thu, 23 Jun 2022 12:46:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232420AbiFWQp5 (ORCPT ); Thu, 23 Jun 2022 12:45:57 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5560748E44; Thu, 23 Jun 2022 09:45:55 -0700 (PDT) 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 E055C61F91; Thu, 23 Jun 2022 16:45:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3D6BC3411B; Thu, 23 Jun 2022 16:45:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656002754; bh=yQX9uP7Qi3xmNcgIDslJRU/lmTA01+Fbl3y0OPRwIJ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fTF91/B6anuKOUi0t7lVdw1UYhjzCOOGNyxUiYt6yXsaqfcEaTlIO/1pmNyNXdYhl rZlKpV+Xdv1MUggz3Qq3sJutIBteNpd0tEMSx8GU7rP/VC0YndxzhrPmdK1dnY8R+b D3KXJgC4keGUh92XzYclmkeUvOKnyJpu4MMOCqoI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Jason A. Donenfeld" , Sebastian Andrzej Siewior , Theodore Tso Subject: [PATCH 4.9 015/264] random: reorder READ_ONCE() in get_random_uXX Date: Thu, 23 Jun 2022 18:40:08 +0200 Message-Id: <20220623164344.496193971@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164344.053938039@linuxfoundation.org> References: <20220623164344.053938039@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior commit 72e5c740f6335e27253b8ff64d23d00337091535 upstream. Avoid the READ_ONCE in commit 4a072c71f49b ("random: silence compiler warnings and fix race") if we can leave the function after arch_get_random_XXX(). Cc: Jason A. Donenfeld Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Theodore Ts'o Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2161,7 +2161,7 @@ static DEFINE_PER_CPU(struct batched_ent u64 get_random_u64(void) { u64 ret; - bool use_lock = READ_ONCE(crng_init) < 2; + bool use_lock; unsigned long flags = 0; struct batched_entropy *batch; static void *previous; @@ -2177,6 +2177,7 @@ u64 get_random_u64(void) warn_unseeded_randomness(&previous); + use_lock = READ_ONCE(crng_init) < 2; batch = &get_cpu_var(batched_entropy_u64); if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags); @@ -2196,7 +2197,7 @@ static DEFINE_PER_CPU(struct batched_ent u32 get_random_u32(void) { u32 ret; - bool use_lock = READ_ONCE(crng_init) < 2; + bool use_lock; unsigned long flags = 0; struct batched_entropy *batch; static void *previous; @@ -2206,6 +2207,7 @@ u32 get_random_u32(void) warn_unseeded_randomness(&previous); + use_lock = READ_ONCE(crng_init) < 2; batch = &get_cpu_var(batched_entropy_u32); if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags);