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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B3F2C433F5 for ; Thu, 6 Oct 2022 16:24:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 89E246B0072; Thu, 6 Oct 2022 12:24:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 84DB06B0073; Thu, 6 Oct 2022 12:24:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6C7088E0001; Thu, 6 Oct 2022 12:24:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5471E6B0072 for ; Thu, 6 Oct 2022 12:24:48 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 1061A120AC3 for ; Thu, 6 Oct 2022 16:24:48 +0000 (UTC) X-FDA: 79991048256.29.086CEF2 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf01.hostedemail.com (Postfix) with ESMTP id 13B264002F for ; Thu, 6 Oct 2022 16:24:45 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 449B31F8C8; Thu, 6 Oct 2022 16:24:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1665073484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mV/oM0ZFOSmZTr1tEI8al4WRLOksCnyDL+Y/DEXpI5s=; b=UpMGEnz8udfBQaYQea0RFWIGZLHq8VrOBgj52x/KJxgkfQbo9PUL5p/nyS4etrbrvNMKPh fN+XR3CloFKxtP83fRcyxMOWd16CNTY3lAy3rTchPXbCFCZFdCtXDbZGLw+MfNvd/rijOp IR8XPzPF4ITG5zf8YYhr11pLUpwah5A= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1665073484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mV/oM0ZFOSmZTr1tEI8al4WRLOksCnyDL+Y/DEXpI5s=; b=otxfHmXsbtMwOZmz0I8Sc9DZTAJO3Yvah3UhZWsIjZrjcfaHEUVz0PTrY55kP5B1vaKkmm X6r81foYz4EqG0Dw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0561F13AC8; Thu, 6 Oct 2022 16:24:44 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id dJZHAUwBP2MOIwAAMHmgww (envelope-from ); Thu, 06 Oct 2022 16:24:44 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 7D4DEA06E9; Thu, 6 Oct 2022 18:24:43 +0200 (CEST) Date: Thu, 6 Oct 2022 18:24:43 +0200 From: Jan Kara To: "Jason A. Donenfeld" Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev, Andreas Noever , Andrew Morton , Andy Shevchenko , Borislav Petkov , Christoph =?utf-8?Q?B=C3=B6hmwalder?= , Christoph Hellwig , Daniel Borkmann , Dave Airlie , Dave Hansen , "David S . Miller" , Eric Dumazet , Florian Westphal , Greg Kroah-Hartman , "H . Peter Anvin" , Herbert Xu , Hugh Dickins , Jakub Kicinski , "James E . J . Bottomley" , Jan Kara , Jason Gunthorpe , Jens Axboe , Johannes Berg , Jonathan Corbet , Jozsef Kadlecsik , KP Singh , Kees Cook , Marco Elver , Mauro Carvalho Chehab , Michael Ellerman , Pablo Neira Ayuso , Paolo Abeni , Theodore Ts'o , Thomas Gleixner , Thomas Graf , Ulf Hansson , Vignesh Raghavendra , Yury Norov , dri-devel@lists.freedesktop.org, kasan-dev@googlegroups.com, kernel-janitors@vger.kernel.org, linux-block@vger.kernel.org, linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2 1/5] treewide: use prandom_u32_max() when possible Message-ID: <20221006162443.b66waqsxlntfeoek@quack3> References: <20221006132510.23374-1-Jason@zx2c4.com> <20221006132510.23374-2-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221006132510.23374-2-Jason@zx2c4.com> ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1665073486; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=mV/oM0ZFOSmZTr1tEI8al4WRLOksCnyDL+Y/DEXpI5s=; b=nbD+Klva8F8OVbWzdXoQlBdy/UAr4/PF1S8U1Heqy2e/B3bJEtGl+fkOZryYFrBjKtRkGp PyyUh9bwL4Z0XU6AezKX3yEdDCKL/wsjL0nRsE76AcKbafCfzDek9d0h7NREIQE67l/Uwh hz2NUVwzXV3Vbl/tSzl8/uuE1CLB4ZY= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=UpMGEnz8; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=otxfHmXs; dmarc=none; spf=pass (imf01.hostedemail.com: domain of jack@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=jack@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1665073486; a=rsa-sha256; cv=none; b=OU/dRGUjCTZqkYcRWyfR+kmwlfDCnylBm2y9qP8OJWvqFdJWGSJSVA7LBpRI1b7L9dCx17 Lp+r8sbnwwChKPh6oGMcnBZ6RPCUpmoLAlhe2il5FpS4slRB/phUZbe0+1soYqsKs7UijO iTUB8pdBGdQJl8P/lwQfjhfxFDtmrtM= X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 13B264002F X-Rspam-User: Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=UpMGEnz8; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=otxfHmXs; dmarc=none; spf=pass (imf01.hostedemail.com: domain of jack@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=jack@suse.cz X-Stat-Signature: 6imudf66gwe9h18ix9koiqekbwcsafpe X-HE-Tag: 1665073485-662838 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 06-10-22 07:25:06, Jason A. Donenfeld wrote: > Rather than incurring a division or requesting too many random bytes for > the given range, use the prandom_u32_max() function, which only takes > the minimum required bytes from the RNG and avoids divisions. > > Reviewed-by: Kees Cook > Reviewed-by: KP Singh > Reviewed-by: Christoph Böhmwalder > Signed-off-by: Jason A. Donenfeld Feel free to add: Reviewed-by: Jan Kara for the ext2, ext4, and lib/sbitmap.c bits. Honza -- Jan Kara SUSE Labs, CR