From patchwork Sun Nov 22 15:35:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 11923915 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C50FEC64E75 for ; Sun, 22 Nov 2020 15:39:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90C4920781 for ; Sun, 22 Nov 2020 15:39:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rPLfAxEf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727317AbgKVPjN (ORCPT ); Sun, 22 Nov 2020 10:39:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727924AbgKVPjK (ORCPT ); Sun, 22 Nov 2020 10:39:10 -0500 Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3897EC0613D3; Sun, 22 Nov 2020 07:39:10 -0800 (PST) Received: by mail-ej1-x641.google.com with SMTP id lv15so13952045ejb.12; Sun, 22 Nov 2020 07:39:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=fl28dO735aCAhko0B6RL7SyZGlL+dtaEdr7rVCrHNgQ=; b=rPLfAxEfQrMaZWxlGBBQ5d77LNndT6OVQI8MQ2T6907z53C9QoVTKOPOFsmL4yC2JW 36wJA7mxNcfbneKzsAqdpifGDGflHREGS2wnjXY4y+noVa17TU09bkb1/5bjIUHCpeDo BztYKy35vV3e+DDGG38CSWfnkDaogGcnAttQ20IRJKGOkG2qFlVSCw3SYBLqd/Esz3uy HOokYMbQI94IaNxVk/4L7hQhSbepslrv1vpfo9BGZfsoappahdARgR6uA7ccqgNZkWkj l5Joo5IHrLaOWvzNLkCvGpA0xM8IJiq2T8OsTs4fJXzxuRrt7Iq33AKxdF1J+cxwtOnW 8aWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=fl28dO735aCAhko0B6RL7SyZGlL+dtaEdr7rVCrHNgQ=; b=XAxFAr8V2/6aHZlPfqer70Fd7490sYPQch986SCZC39jkCoHUwT+rap82CJ5jN0AZS nKUty2HzWNe/cFBFPnUvLpWm5C2EgQeZOqziOmY4kbCNAAh5nxhlCXRrIKr8JqvE8wkA f43Dp9R+wPPSYwZiRIyM5gbdnzlcldF8hshPEcAjP3KvFZTaK1oo8VG1Ai00IaC/hYSP XnepPxU6AS7z6/Hh6CZqUWFe6Ey/o/jYl0yidLxSsFR1q0m1zgO7fvmxKwMqAirZXNZN zcqhDQDXc0o7G/KcXujbviCQOyd+nUYRaV9cQ0MvwdQE67y4BYMH9YlnlwrV5NwDUnAv D+Dw== X-Gm-Message-State: AOAM533W9hzmvNauTpQa+Bey95SEq1gkMcl3f3t9zyeCyIrQo/sTrRyp n9q/fQvx/W5nnQT1YXfM4oL4CR9mPLbPcg== X-Google-Smtp-Source: ABdhPJzReAQ2abZZjO+qZieauY3jPn1AV5BGddQdRsAaDLI8owcy622mYph2MO6f7bQjG6vikUT4oQ== X-Received: by 2002:a17:906:1c87:: with SMTP id g7mr35785480ejh.37.1606059549013; Sun, 22 Nov 2020 07:39:09 -0800 (PST) Received: from localhost.localdomain (host109-152-100-189.range109-152.btcentralplus.com. [109.152.100.189]) by smtp.gmail.com with ESMTPSA id q19sm3693742ejz.90.2020.11.22.07.39.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Nov 2020 07:39:08 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , linux-block@vger.kernel.org, Omar Sandoval Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2 4/4] sbitmap: simplify wrap check Date: Sun, 22 Nov 2020 15:35:48 +0000 Message-Id: <120b9b0870719675c91764822016597bdfa3ee15.1606058975.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org __sbitmap_get_word() doesn't warp if it's starting from the beginning (i.e. initial hint is 0). Instead of stashing the original hint just set @wrap accordingly. Signed-off-by: Pavel Begunkov --- lib/sbitmap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/lib/sbitmap.c b/lib/sbitmap.c index c18b518a16ba..d693d9213ceb 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -97,9 +97,11 @@ EXPORT_SYMBOL_GPL(sbitmap_resize); static int __sbitmap_get_word(unsigned long *word, unsigned long depth, unsigned int hint, bool wrap) { - unsigned int orig_hint = hint; int nr; + /* don't wrap if starting from 0 */ + wrap = wrap && hint; + while (1) { nr = find_next_zero_bit(word, depth, hint); if (unlikely(nr >= depth)) { @@ -108,8 +110,8 @@ static int __sbitmap_get_word(unsigned long *word, unsigned long depth, * offset to 0 in a failure case, so start from 0 to * exhaust the map. */ - if (orig_hint && hint && wrap) { - hint = orig_hint = 0; + if (hint && wrap) { + hint = 0; continue; } return -1;