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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B8FAC83F17 for ; Mon, 28 Aug 2023 10:51:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232230AbjH1Kus (ORCPT ); Mon, 28 Aug 2023 06:50:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232308AbjH1Kud (ORCPT ); Mon, 28 Aug 2023 06:50:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67740E4C for ; Mon, 28 Aug 2023 03:50:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 47C4964481 for ; Mon, 28 Aug 2023 10:50:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2529BC433C9; Mon, 28 Aug 2023 10:50:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693219807; bh=9XMAmSwksTgUpeSTYZ0R0ntinrxg0G3QrkflwwgiIX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mBzporTktaUNlZINJTOJji+U6nO51gn/zgw0Dp/SbnrFBjS4Ui2AKLj5a9SPCbNdV QIxX++phhL1PESKIh9yTr+OWlIXy4DYst7zgWBmra1jSC7aLKsUehXkHxfVuP8C1+v TtHjzTG5slknD08cmQFC0U96qQPI4nRWi93aOcRA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oscar Salvador , Naoya Horiguchi , Vlastimil Babka , Qian Cai , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.10 79/84] mm,hwpoison: refactor get_any_page Date: Mon, 28 Aug 2023 12:14:36 +0200 Message-ID: <20230828101151.965205685@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101149.146126827@linuxfoundation.org> References: <20230828101149.146126827@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oscar Salvador [ Upstream commit 8295d535e2aa198bdf65a4045d622df38955ffe2 ] Patch series "HWPoison: Refactor get page interface", v2. This patch (of 3): When we want to grab a refcount via get_any_page, we call __get_any_page that calls get_hwpoison_page to get the actual refcount. get_any_page() is only there because we have a sort of retry mechanism in case the page we met is unknown to us or if we raced with an allocation. Also __get_any_page() prints some messages about the page type in case the page was a free page or the page type was unknown, but if anything, we only need to print a message in case the pagetype was unknown, as that is reporting an error down the chain. Let us merge get_any_page() and __get_any_page(), and let the message be printed in soft_offline_page. While we are it, we can also remove the 'pfn' parameter as it is no longer used. Link: https://lkml.kernel.org/r/20201204102558.31607-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20201204102558.31607-2-osalvador@suse.de Signed-off-by: Oscar Salvador Acked-by: Naoya Horiguchi Acked-by: Vlastimil Babka Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Stable-dep-of: e2c1ab070fdc ("mm: memory-failure: fix unexpected return value in soft_offline_page()") Signed-off-by: Sasha Levin --- mm/memory-failure.c | 101 +++++++++++++++++++------------------------- 1 file changed, 43 insertions(+), 58 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b21dd4a793926..71fd546dbdc37 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1690,70 +1690,51 @@ EXPORT_SYMBOL(unpoison_memory); /* * Safely get reference count of an arbitrary page. - * Returns 0 for a free page, -EIO for a zero refcount page - * that is not free, and 1 for any other page type. - * For 1 the page is returned with increased page count, otherwise not. + * Returns 0 for a free page, 1 for an in-use page, -EIO for a page-type we + * cannot handle and -EBUSY if we raced with an allocation. + * We only incremented refcount in case the page was already in-use and it is + * a known type we can handle. */ -static int __get_any_page(struct page *p, unsigned long pfn, int flags) +static int get_any_page(struct page *p, int flags) { - int ret; + int ret = 0, pass = 0; + bool count_increased = false; if (flags & MF_COUNT_INCREASED) - return 1; - - /* - * When the target page is a free hugepage, just remove it - * from free hugepage list. - */ - if (!get_hwpoison_page(p)) { - if (PageHuge(p)) { - pr_info("%s: %#lx free huge page\n", __func__, pfn); - ret = 0; - } else if (is_free_buddy_page(p)) { - pr_info("%s: %#lx free buddy page\n", __func__, pfn); - ret = 0; - } else if (page_count(p)) { - /* raced with allocation */ + count_increased = true; + +try_again: + if (!count_increased && !get_hwpoison_page(p)) { + if (page_count(p)) { + /* We raced with an allocation, retry. */ + if (pass++ < 3) + goto try_again; ret = -EBUSY; - } else { - pr_info("%s: %#lx: unknown zero refcount page type %lx\n", - __func__, pfn, p->flags); + } else if (!PageHuge(p) && !is_free_buddy_page(p)) { + /* We raced with put_page, retry. */ + if (pass++ < 3) + goto try_again; ret = -EIO; } } else { - /* Not a free page */ - ret = 1; - } - return ret; -} - -static int get_any_page(struct page *page, unsigned long pfn, int flags) -{ - int ret = __get_any_page(page, pfn, flags); - - if (ret == -EBUSY) - ret = __get_any_page(page, pfn, flags); - - if (ret == 1 && !PageHuge(page) && - !PageLRU(page) && !__PageMovable(page)) { - /* - * Try to free it. - */ - put_page(page); - shake_page(page, 1); - - /* - * Did it turn free? - */ - ret = __get_any_page(page, pfn, 0); - if (ret == 1 && !PageLRU(page)) { - /* Drop page reference which is from __get_any_page() */ - put_page(page); - pr_info("soft_offline: %#lx: unknown non LRU page type %lx (%pGp)\n", - pfn, page->flags, &page->flags); - return -EIO; + if (PageHuge(p) || PageLRU(p) || __PageMovable(p)) { + ret = 1; + } else { + /* + * A page we cannot handle. Check whether we can turn + * it into something we can handle. + */ + if (pass++ < 3) { + put_page(p); + shake_page(p, 1); + count_increased = false; + goto try_again; + } + put_page(p); + ret = -EIO; } } + return ret; } @@ -1922,7 +1903,7 @@ int soft_offline_page(unsigned long pfn, int flags) return -EIO; if (PageHWPoison(page)) { - pr_info("soft offline: %#lx page already poisoned\n", pfn); + pr_info("%s: %#lx page already poisoned\n", __func__, pfn); if (flags & MF_COUNT_INCREASED) put_page(page); return 0; @@ -1930,17 +1911,21 @@ int soft_offline_page(unsigned long pfn, int flags) retry: get_online_mems(); - ret = get_any_page(page, pfn, flags); + ret = get_any_page(page, flags); put_online_mems(); - if (ret > 0) + if (ret > 0) { ret = soft_offline_in_use_page(page); - else if (ret == 0) + } else if (ret == 0) { if (soft_offline_free_page(page) && try_again) { try_again = false; flags &= ~MF_COUNT_INCREASED; goto retry; } + } else if (ret == -EIO) { + pr_info("%s: %#lx: unknown page type: %lx (%pGP)\n", + __func__, pfn, page->flags, &page->flags); + } return ret; } -- 2.40.1