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 BFAB4C4743E for ; Sun, 6 Jun 2021 19:11:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9AE061208 for ; Sun, 6 Jun 2021 19:11:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231211AbhFFTNl (ORCPT ); Sun, 6 Jun 2021 15:13:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230158AbhFFTMp (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 B4C6DC061767; Sun, 6 Jun 2021 12:10:54 -0700 (PDT) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lpyAd-0056ZA-JV; Sun, 06 Jun 2021 19:10:51 +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 06/37] copy_page_to_iter(): fix ITER_DISCARD case Date: Sun, 6 Jun 2021 19:10:20 +0000 Message-Id: <20210606191051.1216821-6-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 we need to advance the iterator... Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- lib/iov_iter.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 12fb04b23143..c8877cffb7bc 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -965,9 +965,12 @@ static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes size_t wanted = copy_to_iter(kaddr + offset, bytes, i); kunmap_atomic(kaddr); return wanted; - } else if (unlikely(iov_iter_is_discard(i))) + } else if (unlikely(iov_iter_is_discard(i))) { + if (unlikely(i->count < bytes)) + bytes = i->count; + i->count -= bytes; return bytes; - else if (likely(!iov_iter_is_pipe(i))) + } else if (likely(!iov_iter_is_pipe(i))) return copy_page_to_iter_iovec(page, offset, bytes, i); else return copy_page_to_iter_pipe(page, offset, bytes, i); -- 2.11.0