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 BB06DC433EF for ; Fri, 4 Feb 2022 20:01:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237051AbiBDUA7 (ORCPT ); Fri, 4 Feb 2022 15:00:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235624AbiBDT7K (ORCPT ); Fri, 4 Feb 2022 14:59:10 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62001C061755 for ; Fri, 4 Feb 2022 11:59:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=NOZFCIAHs14S6ShgmEZTYVvlwYIX+9q1FzDwIHERWMU=; b=oSzUzWyoXWPtOg5IDBWJS2HMsY LIoT7FbLieUlfRoqAfRmp+S5USjt7whN6+vx0tWMS+rT4fg6TIwnpgzKT+bNASFMiG1xLjEbLMKyv jAIsN+Pk9H7Qm4nszlO4EIRKLGmVXTyTh7PJtSSHwOm4PIZqIyIR7N5jR+KWmC52n2bxR3Ya3oAYp n8SAiuLo9SRHmXntPDmrDZgennQCO60kdOCcqio2Bf+PkxbZLSjtFLTzM23uCWQ0IbLzNYAWRQd0V ElOzXete8NXsvVAxnbv+jsL9HJDTRxvcbjl1ijsgW7a1jj7pKS/B48lde/TSUGiGT3O/jXIzQVp4H Szz3ek6Q==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nG4jT-007Ll3-Nl; Fri, 04 Feb 2022 19:58:59 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org Subject: [PATCH 01/75] mm/gup: Increment the page refcount before the pincount Date: Fri, 4 Feb 2022 19:57:38 +0000 Message-Id: <20220204195852.1751729-2-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220204195852.1751729-1-willy@infradead.org> References: <20220204195852.1751729-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should always increase the refcount before doing anything else to the page so that other page users see the elevated refcount first. Signed-off-by: Matthew Wilcox (Oracle) --- mm/gup.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index a9d4d724aef7..08020987dfc0 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -220,18 +220,18 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags) if (WARN_ON_ONCE(page_ref_count(page) <= 0)) return false; - if (hpage_pincount_available(page)) - hpage_pincount_add(page, 1); - else - refs = GUP_PIN_COUNTING_BIAS; - /* * Similar to try_grab_compound_head(): even if using the * hpage_pincount_add/_sub() routines, be sure to * *also* increment the normal page refcount field at least * once, so that the page really is pinned. */ - page_ref_add(page, refs); + if (hpage_pincount_available(page)) { + page_ref_add(page, 1); + hpage_pincount_add(page, 1); + } else { + page_ref_add(page, GUP_PIN_COUNTING_BIAS); + } mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_ACQUIRED, 1); } -- 2.34.1