From patchwork Mon Jul 12 06:01:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 474114 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 2DF09C11F67 for ; Mon, 12 Jul 2021 06:57:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19FE9613BE for ; Mon, 12 Jul 2021 06:57:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238954AbhGLHAg (ORCPT ); Mon, 12 Jul 2021 03:00:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:57648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233473AbhGLG6m (ORCPT ); Mon, 12 Jul 2021 02:58:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 863F0613CA; Mon, 12 Jul 2021 06:55:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626072954; bh=Oy13UB0ME+Nb4/IQRgeCJ2zrfoqR/8cCRtL+p4W3lEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UyZqqZoabB5VNCapgJdVhm122bb56GmgMVE6GttH+h55UsANXpf/fY3yCxAzZ7tDB 9xPudMLamTi/EAhPUV54Io3VG0JE786BC6vwJpfsMkyw7dXCv1h/kTBf7KKF55XplU X7rXNpcou/FhQsFsWNbV1A+a1/BSq3Eyl7bmOXK0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 5.12 034/700] copy_page_to_iter(): fix ITER_DISCARD case Date: Mon, 12 Jul 2021 08:01:57 +0200 Message-Id: <20210712060929.437420872@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@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 @@ -906,9 +906,12 @@ 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);