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 5E7CAC4743D for ; Sun, 6 Jun 2021 19:12:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44A7C61421 for ; Sun, 6 Jun 2021 19:12:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231303AbhFFTOA (ORCPT ); Sun, 6 Jun 2021 15:14:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230156AbhFFTMp (ORCPT ); Sun, 6 Jun 2021 15:12:45 -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 534F8C06178B; Sun, 6 Jun 2021 12:10:55 -0700 (PDT) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lpyAg-0056b1-8J; Sun, 06 Jun 2021 19:10:54 +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 22/37] iterate_and_advance(): get rid of magic in case when n is 0 Date: Sun, 6 Jun 2021 19:10:36 +0000 Message-Id: <20210606191051.1216821-22-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 iov_iter_advance() needs to do some non-trivial work when it's given 0 as argument (skip all empty iovecs, mostly). We used to implement it via iterate_and_advance(); we no longer do so and for all other users of iterate_and_advance() zero length is a no-op. Signed-off-by: Al Viro --- lib/iov_iter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 906e9d49c487..ebb907c6393c 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -117,7 +117,7 @@ #define iterate_and_advance(i, n, v, I, B, K, X) { \ if (unlikely(i->count < n)) \ n = i->count; \ - if (i->count) { \ + if (likely(n)) { \ size_t skip = i->iov_offset; \ if (likely(iter_is_iovec(i))) { \ const struct iovec *iov; \ -- 2.11.0