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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 A4C6AC4743E for ; Sun, 6 Jun 2021 19:12:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 912A66141E for ; Sun, 6 Jun 2021 19:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231419AbhFFTOV (ORCPT ); Sun, 6 Jun 2021 15:14:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230222AbhFFTMv (ORCPT ); Sun, 6 Jun 2021 15:12:51 -0400 Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [IPv6:2607:5300:60:148a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A663C061224; Sun, 6 Jun 2021 12:10:57 -0700 (PDT) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lpyAh-0056cD-Bp; Sun, 06 Jun 2021 19:10:55 +0000 From: Al Viro To: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, David Sterba , Miklos Szeredi , Anton Altaparmakov , David Howells , Matthew Wilcox , Pavel Begunkov Subject: [RFC PATCH 31/37] iterate_xarray(): only of the first iteration we might get offset != 0 Date: Sun, 6 Jun 2021 19:10:45 +0000 Message-Id: <20210606191051.1216821-31-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210606191051.1216821-1-viro@zeniv.linux.org.uk> References: <20210606191051.1216821-1-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org recalculating offset on each iteration is pointless - on all subsequent passes through the loop it will be zero anyway. Signed-off-by: Al Viro --- lib/iov_iter.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index c1580e574d76..9ecbf59c3378 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -70,9 +70,9 @@ __label__ __out; \ size_t __off = 0; \ struct page *head = NULL; \ - size_t offset; \ loff_t start = i->xarray_start + i->iov_offset; \ - pgoff_t index = start >> PAGE_SHIFT; \ + unsigned offset = start % PAGE_SIZE; \ + pgoff_t index = start / PAGE_SIZE; \ int j; \ \ XA_STATE(xas, i->xarray, index); \ @@ -89,7 +89,6 @@ for (j = (head->index < index) ? index - head->index : 0; \ j < thp_nr_pages(head); j++) { \ void *kaddr = kmap_local_page(head + j); \ - offset = (start + __off) % PAGE_SIZE; \ base = kaddr + offset; \ len = PAGE_SIZE - offset; \ len = min(n, len); \ @@ -100,6 +99,7 @@ n -= len; \ if (left || n == 0) \ goto __out; \ + offset = 0; \ } \ } \ __out: \ -- 2.11.0