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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3D5F5C54791 for ; Wed, 13 Mar 2024 08:47:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=xN1tfOedO3Wz+u77CeqDCrSJlY7VFe2qPGj1TaLmkpQ=; b=quhnlZxhv8kXMT NVq9SDhTdyGu1BEIaklPk15y8TLG2N//K0fC/69M+Snrf0YF5PbKyWQkkLw8sppszW3NuP6oY5uwq EU1w1eYSTJR9FP11/Y8UX6b6bypMBN+AGCamQ6PtPd6ufW7HeWZePXB8SIwmMpgsR2NI6qsdrt9Pt LS24WKEGgsI+yqsCUqCpJuUdAPD7o7vSwGHzSXvmRVLjeczdE7JBFKjoDdNNnMMhAe8uxISqxNm+i FqDQAMGhxPs5U1191kaSo2yg8LGORkm+yIK3Ps/fCaUfXVVrS9ECnfL1YdVi9ooepk1FjBNIq8gJ4 JgF98cQqhNQ9e6nuQeLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rkKGc-00000009N5H-3RNC; Wed, 13 Mar 2024 08:47:18 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rkKGY-00000009N4D-35K4 for linux-mtd@lists.infradead.org; Wed, 13 Mar 2024 08:47:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id AE8706104E; Wed, 13 Mar 2024 08:47:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A3BEC433C7; Wed, 13 Mar 2024 08:47:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710319633; bh=yakn8DcYyX6FHUb9D/6Aegg8RoUb6WoaYCsMozwxIKw=; h=From:To:Cc:Subject:Date:From; b=Zy4eA+ZOxcbi0qOUZY7hjDjyCYobz5eb5R0q4k/kV9pzxxDR6bhSb0CHxMMB4bbY8 Abm7lYB8ciTbbMqd0TxHS5cTej35LSdDsvBGTRtIG7gK97XiWxE4Ic6DKv+yxvLHed 0gkV/OJr/KOQld5dmGNwO40uY1e6BrCRCkq7FugPr2T58SK7hNH7k5cm63BsfC9UqE EaoQHWs4dHszp+yioksWs3p3TjUkLG5XNxj2sRCC+59QO2eRK0PyrbP0SZPEGzxbCl hRqnsXCctrInJvM3UxF8cmnL354M+9H9UQfJHcl7wNgvJTxMMk5aiKKrpEuNw8IW9C Wdo4RA9WPWQfQ== From: Arnd Bergmann To: Richard Weinberger , Miquel Raynal , Vignesh Raghavendra , Daniel Golle , Zhihao Cheng Cc: Arnd Bergmann , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] mtd: ubi: avoid expensive do_div() on 32-bit machines Date: Wed, 13 Mar 2024 09:46:52 +0100 Message-Id: <20240313084707.3292300-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240313_014714_848617_8AFBDC87 X-CRM114-Status: GOOD ( 11.41 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org From: Arnd Bergmann The use of do_div() in ubi_nvmem_reg_read() makes calling it on 32-bit machines rather expensive. Since the 'from' variable is known to be a 32-bit quantity, it is clearly never needed and can be optimized into a regular division operation. Fixes: b8a77b9a5f9c ("mtd: ubi: fix NVMEM over UBI volumes on 32-bit systems") Fixes: 3ce485803da1 ("mtd: ubi: provide NVMEM layer over UBI volumes") Signed-off-by: Arnd Bergmann --- drivers/mtd/ubi/nvmem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/ubi/nvmem.c b/drivers/mtd/ubi/nvmem.c index 8aeb9c428e51..a94a1a9aaec1 100644 --- a/drivers/mtd/ubi/nvmem.c +++ b/drivers/mtd/ubi/nvmem.c @@ -6,7 +6,6 @@ /* UBI NVMEM provider */ #include "ubi.h" #include -#include /* List of all NVMEM devices */ static LIST_HEAD(nvmem_devices); @@ -27,14 +26,15 @@ static int ubi_nvmem_reg_read(void *priv, unsigned int from, struct ubi_nvmem *unv = priv; struct ubi_volume_desc *desc; uint32_t offs; - uint64_t lnum = from; + uint32_t lnum; int err = 0; desc = ubi_open_volume(unv->ubi_num, unv->vol_id, UBI_READONLY); if (IS_ERR(desc)) return PTR_ERR(desc); - offs = do_div(lnum, unv->usable_leb_size); + offs = from % unv->usable_leb_size; + lnum = from / unv->usable_leb_size; while (bytes_left) { to_read = unv->usable_leb_size - offs; -- 2.39.2 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/