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 A0559C433FE for ; Sun, 30 Oct 2022 03:01:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229696AbiJ3DBD (ORCPT ); Sat, 29 Oct 2022 23:01:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229549AbiJ3DBC (ORCPT ); Sat, 29 Oct 2022 23:01:02 -0400 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29A5D3120C; Sat, 29 Oct 2022 20:01:01 -0700 (PDT) Received: by mail-pj1-f47.google.com with SMTP id 3-20020a17090a0f8300b00212d5cd4e5eso13151483pjz.4; Sat, 29 Oct 2022 20:01:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=L57Nna1Rv8qEqcyUYnO8glciVH+3HJrUIebXRiDcDRk=; b=4dMdEZdYUivL0mImkS43nFL7OTCPcw6PhGulvX+WZY7SHYI/VX0NODTrUO+RgZMbBr 54qv0omEmMWBDNaTsLBUm4s0nr27Q87tIV3Dw2UChVGKqdGXxc7urYs/0lYsuFpTZXPI eTVG3CVGAnOafuMknuiTUBIjWZnJchNTk2BKcfEsxQoJUBUkgvg3o4H5nUxjeCSxXOKU 175S33kq8MvObzvTEZOqliTN6YKVYrWfymH0OpXWKaTHiMgbeyqWItPwhVh5KqFJvzH3 N2eGdemRXQ9ln14z05ca8TxefqysMBO/PJfR3+vdvnkGGEefSAclNhur0a3Cmh5EuIlk K2MQ== X-Gm-Message-State: ACrzQf2BAK0oRZZGwKmjOpsYIayJKjObLO8u1cPq6YDyjs8v9gkZuykM k44yzvKbT9Q/eCEwF/xx1so= X-Google-Smtp-Source: AMsMyM6KEs8BdLvR89JK6qwNIWFT/QJ5AO1dPiPjzuYo+c3mrxv3gKDAf46FxNDMulcSoL/BP6m0MA== X-Received: by 2002:a17:903:124e:b0:179:da2f:244e with SMTP id u14-20020a170903124e00b00179da2f244emr7357905plh.169.1667098860592; Sat, 29 Oct 2022 20:01:00 -0700 (PDT) Received: from [192.168.3.219] ([98.51.102.78]) by smtp.gmail.com with ESMTPSA id w15-20020a17090a028f00b001f94d25bfabsm1662704pja.28.2022.10.29.20.00.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 29 Oct 2022 20:00:59 -0700 (PDT) Message-ID: <8ccaabc1-2834-dad6-7d46-19bfc2adcc9a@acm.org> Date: Sat, 29 Oct 2022 20:00:58 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.0 Subject: Re: [PATCH v2] block: simplify blksize_bits() implementation Content-Language: en-US To: Dawei Li , axboe@kernel.dk Cc: hch@lst.de, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 10/29/22 19:17, Dawei Li wrote: > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 57ed49f20d2e..7b537afe8b38 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1349,12 +1349,7 @@ static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr, > /* assumes size > 256 */ > static inline unsigned int blksize_bits(unsigned int size) > { > - unsigned int bits = 8; > - do { > - bits++; > - size >>= 1; > - } while (size > 256); > - return bits; > + return order_base_2((size + SECTOR_SIZE - 1) >> SECTOR_SHIFT) + SECTOR_SHIFT; > } Why the rounding ("+ SECTOR_SIZE - 1")? The blksize_bits() argument should be an argument of two. Thanks, Bart.