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 ED2B0C4743D for ; Sun, 6 Jun 2021 19:12:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D045A61421 for ; Sun, 6 Jun 2021 19:12:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231280AbhFFTNw (ORCPT ); Sun, 6 Jun 2021 15:13:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230172AbhFFTMq (ORCPT ); Sun, 6 Jun 2021 15:12:46 -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 D6334C061795; 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-0056bM-FZ; 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 24/37] iov_iter: unify iterate_iovec and iterate_kvec Date: Sun, 6 Jun 2021 19:10:38 +0000 Message-Id: <20210606191051.1216821-24-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 The differences between iterate_iovec and iterate_kvec are minor: * kvec callback is treated as if it returned 0 * initialization of __p is with i->iov and i->kvec resp. which is trivially dealt with. No code generation changes - compiler is quite capable of turning left = ((void)(STEP), 0); __v.iov_len -= left; (with no accesses to left downstream) and (void)(STEP); into the same code. Signed-off-by: Al Viro --- lib/iov_iter.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 578f40788943..19c103e9ef7d 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -16,10 +16,10 @@ #define PIPE_PARANOIA /* for now */ +/* covers iovec and kvec alike */ #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ size_t left; \ size_t wanted = n; \ - __p = i->iov; \ do { \ __v.iov_len = min(n, __p->iov_len - skip); \ if (likely(__v.iov_len)) { \ @@ -37,25 +37,6 @@ n = wanted - n; \ } -#define iterate_kvec(i, n, __v, __p, skip, STEP) { \ - size_t wanted = n; \ - __p = i->kvec; \ - do { \ - __v.iov_len = min(n, __p->iov_len - skip); \ - if (likely(__v.iov_len)) { \ - __v.iov_base = __p->iov_base + skip; \ - (void)(STEP); \ - skip += __v.iov_len; \ - n -= __v.iov_len; \ - if (skip < __p->iov_len) \ - break; \ - } \ - __p++; \ - skip = 0; \ - } while (n); \ - n = wanted - n; \ -} - #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ struct bvec_iter __start; \ __start.bi_size = n; \ @@ -109,7 +90,7 @@ if (likely(n)) { \ size_t skip = i->iov_offset; \ if (likely(iter_is_iovec(i))) { \ - const struct iovec *iov; \ + const struct iovec *iov = i->iov; \ struct iovec v; \ iterate_iovec(i, n, v, iov, skip, (I)) \ i->nr_segs -= iov - i->iov; \ @@ -123,9 +104,10 @@ i->nr_segs -= i->bvec - bvec; \ skip = __bi.bi_bvec_done; \ } else if (iov_iter_is_kvec(i)) { \ - const struct kvec *kvec; \ + const struct kvec *kvec = i->kvec; \ struct kvec v; \ - iterate_kvec(i, n, v, kvec, skip, (K)) \ + iterate_iovec(i, n, v, kvec, skip, \ + ((void)(K),0)) \ i->nr_segs -= kvec - i->kvec; \ i->kvec = kvec; \ } else if (iov_iter_is_xarray(i)) { \ -- 2.11.0