From patchwork Fri Aug 6 11:22:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 12423267 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=ham 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 E3994C4338F for ; Fri, 6 Aug 2021 11:22:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB70A60EE8 for ; Fri, 6 Aug 2021 11:22:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242044AbhHFLXL (ORCPT ); Fri, 6 Aug 2021 07:23:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231173AbhHFLXJ (ORCPT ); Fri, 6 Aug 2021 07:23:09 -0400 Received: from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com [IPv6:2a00:1450:4864:20::32c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4F46C061798; Fri, 6 Aug 2021 04:22:52 -0700 (PDT) Received: by mail-wm1-x32c.google.com with SMTP id k38-20020a05600c1ca6b029025af5e0f38bso8643180wms.5; Fri, 06 Aug 2021 04:22:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=Jd6SDWe5bP1W9aLKeKIqrkoSJGtHDp+fK9q/kasAchc=; b=TsrhJeomucBYTnCk3vTYAMK/GujB3r3QJHd/WsBX3YzZEcrd5qiU5qSX2nbGkCVxDW dLXVDg3xB3jmBUEIov8a+ILVRvOEq60fjqnUuBpNiJeWY/MRA9CERGfS+WYC25dcdgsv XObImycmWspbAAawI6xgy4W9xf0MN3ggD/le73GCcOtXU7ZXxE0i1VQyw5aeT87k4Ri/ +NRHZU2JGFQh7mFz4MpTf4ND18HbEhQct+ZMec4vbpIVtONY8f018adIl+Wc1hho/ou5 TcydTpAdtyUUuL/aHyiL6GLa8xOW7k17GJViHZmnPP4WzRWGjeNN1nxi2yov/cq9pGWg MGiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=Jd6SDWe5bP1W9aLKeKIqrkoSJGtHDp+fK9q/kasAchc=; b=RYBIB5AtTec+Efy8fyiIzO2LO1rTVxwlc7FMSXceGKRxjIBjNbWmeytNuMX2r9dSnH Rwz0kGeA7UKJZaH6tfHVKXL3v+NMQWThFYi0adNYTBp46BnkrdwYBt7y1Ke/z3oghqzM VjaY4NZV2fhJeY4Hf2ACrqiZXKVJ3RGOZ3u/dLABUnJDUueQVG2NAJJmNVIqiNxXcZy4 xAuVsxPHc/4wVY9YBEfHuyJgS/ScI1gVTbSSSyQkHMlUXwugVXBDT5T5NKjRz9UjYiVW eJXcUekSd0xabsQBrtaxyBJOvfNuXAysjY9upW9CASzSeOcZak27ZbTcLWpvh998NQIE y0Rw== X-Gm-Message-State: AOAM532WrhUa8mlN69yTfEnTjvMGDqNZs4B1pWsRgucxaR9N7i4WcUPk Pz5VBKk1EuR/ZNa/kNJjZLQ= X-Google-Smtp-Source: ABdhPJyOAVveugaFzsVI0ZfcFSXOUGGnR+OLUhC1bNuCMSh1Jrnlq1ocE5eW5xN3Leps75rxSlynBA== X-Received: by 2002:a05:600c:2942:: with SMTP id n2mr20073552wmd.152.1628248971542; Fri, 06 Aug 2021 04:22:51 -0700 (PDT) Received: from localhost.localdomain ([85.255.237.205]) by smtp.gmail.com with ESMTPSA id j4sm8285654wmi.4.2021.08.06.04.22.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Aug 2021 04:22:51 -0700 (PDT) From: Pavel Begunkov To: Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] fs: optimise generic_write_check_limits() Date: Fri, 6 Aug 2021 12:22:10 +0100 Message-Id: X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Even though ->s_maxbytes is used by generic_write_check_limits() only in case of O_LARGEFILE, the value is loaded unconditionally, which is heavy and takes 4 indirect loads. Optimise it by not touching ->s_maxbytes, if it's not going to be used. Signed-off-by: Pavel Begunkov --- fs/read_write.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 9db7adf160d2..db662d0c3cfa 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1609,9 +1609,8 @@ SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, */ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) { - struct inode *inode = file->f_mapping->host; - loff_t max_size = inode->i_sb->s_maxbytes; loff_t limit = rlimit(RLIMIT_FSIZE); + loff_t max_size = MAX_NON_LFS; if (limit != RLIM_INFINITY) { if (pos >= limit) { @@ -1621,8 +1620,11 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) *count = min(*count, limit - pos); } - if (!(file->f_flags & O_LARGEFILE)) - max_size = MAX_NON_LFS; + if (file->f_flags & O_LARGEFILE) { + struct inode *inode = file->f_mapping->host; + + max_size = inode->i_sb->s_maxbytes; + } if (unlikely(pos >= max_size)) return -EFBIG;