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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 4B534C07E96 for ; Sun, 11 Jul 2021 12:00:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AFDB6113C for ; Sun, 11 Jul 2021 12:00:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232730AbhGKMDF (ORCPT ); Sun, 11 Jul 2021 08:03:05 -0400 Received: from wforward1-smtp.messagingengine.com ([64.147.123.30]:47643 "EHLO wforward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232658AbhGKMDE (ORCPT ); Sun, 11 Jul 2021 08:03:04 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailforward.west.internal (Postfix) with ESMTP id D27651AC0D1D; Sun, 11 Jul 2021 08:00:16 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Sun, 11 Jul 2021 08:00:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=Ij0nAi 3bpno/dNIq5ikjF0o7CbKhXSsPi2Mz+Qnwlnc=; b=gYTAFEkc7tPoyB+GV82tyc gkKqrAoXGP3Nlcg+Jp/UNhRith1epPtGwywsI2OFK9GHqwJNUgl1Uk3KShw1DOqQ 4GucBCIVM7qFq3UwKzC7FlYeANvsKoLYwTw+jQsqmSA3s5Li02pve078vi7OrBLE +r3rgEEjD9DC/oMp3aTMU0iCUBqXzFHpXzXTft169HgDQVcHyIanLxqG11EifZ1g u9v8Kt6F51Bld9MV5lzLIHgtsrMxttg4sM4I3T8IHrANwDQ4sVslpNZfBvH/yMiX jGdu/0b8clCJkn+wXQDU4YgdikG1DFU3EoDR6LozZvWcJlwayvm/NPkkbje3U58w == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvtddruddtgdegiecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucggtffrrghtthgvrhhnpeeiteevheeuvdfhtdfgvdeiieehheefleevveehjedute evueevledujeejgfetheenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgr ihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 11 Jul 2021 08:00:15 -0400 (EDT) Subject: FAILED: patch "[PATCH] teach copy_page_to_iter() to handle compound pages" failed to apply to 5.4-stable tree To: viro@zeniv.linux.org.uk Cc: From: Date: Sun, 11 Jul 2021 14:00:14 +0200 Message-ID: <1626004814159241@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 08aa64796016cb47b2ef3d0924653b4d944b0d65 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 29 Apr 2021 20:42:25 -0400 Subject: [PATCH] teach copy_page_to_iter() to handle compound pages In situation when copy_page_to_iter() got a compound page the current code would only work on systems with no CONFIG_HIGHMEM. It *is* the majority of real-world setups, or we would've drown in bug reports by now. Still needs fixing. Current variant works for solitary page; rename that to __copy_page_to_iter() and turn the handling of compound pages into a loop over subpages. Cc: stable@vger.kernel.org Signed-off-by: Al Viro diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 8f5ce5b1ff91..12fb04b23143 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -957,11 +957,9 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) return false; } -size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, +static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { - if (unlikely(!page_copy_sane(page, offset, bytes))) - return 0; if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { void *kaddr = kmap_atomic(page); size_t wanted = copy_to_iter(kaddr + offset, bytes, i); @@ -974,6 +972,30 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, else return copy_page_to_iter_pipe(page, offset, bytes, i); } + +size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, + struct iov_iter *i) +{ + size_t res = 0; + if (unlikely(!page_copy_sane(page, offset, bytes))) + return 0; + page += offset / PAGE_SIZE; // first subpage + offset %= PAGE_SIZE; + while (1) { + size_t n = __copy_page_to_iter(page, offset, + min(bytes, (size_t)PAGE_SIZE - offset), i); + res += n; + bytes -= n; + if (!bytes || !n) + break; + offset += n; + if (offset == PAGE_SIZE) { + page++; + offset = 0; + } + } + return res; +} EXPORT_SYMBOL(copy_page_to_iter); size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,