From patchwork Mon Jul 12 06:06:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 474613 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 D091DC07E9C for ; Mon, 12 Jul 2021 06:15:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDDB8610A6 for ; Mon, 12 Jul 2021 06:15:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233391AbhGLGRw (ORCPT ); Mon, 12 Jul 2021 02:17:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:35982 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233357AbhGLGRt (ORCPT ); Mon, 12 Jul 2021 02:17:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9509A6101E; Mon, 12 Jul 2021 06:15:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626070501; bh=rO/RhaazhH95a5m3BOCizCs4L9WqaxRG3+s3FZal+FQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E3RAw32a/MrdiKv1Bha7pQW1jzNFNr+YsrKwJ6fBZXKvmjAI4n3YvW2Mkodq4c/o7 DEpMAvEMrZonE3Xn/r33/Ff1aj+Uwffe/ATpwGEKQeEawivjQR/Sr4Yzc/zbHljvza QKKNzBNTFJiT0JJbgWKHmUd6+5i2brURP7sYi7BE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 5.4 018/348] copy_page_to_iter(): fix ITER_DISCARD case Date: Mon, 12 Jul 2021 08:06:42 +0200 Message-Id: <20210712060702.570386729@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060659.886176320@linuxfoundation.org> References: <20210712060659.886176320@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Al Viro commit a506abc7b644d71966a75337d5a534f531b3cdc4 upstream. we need to advance the iterator... Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- lib/iov_iter.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -896,9 +896,12 @@ size_t copy_page_to_iter(struct page *pa 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);