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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 B2BA6C43331 for ; Mon, 30 Mar 2020 02:33:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89A6220842 for ; Mon, 30 Mar 2020 02:33:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="w1Utm7e6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729251AbgC3Cdy (ORCPT ); Sun, 29 Mar 2020 22:33:54 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:34214 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729225AbgC3Cdu (ORCPT ); Sun, 29 Mar 2020 22:33:50 -0400 Received: by mail-qk1-f194.google.com with SMTP id i6so17556414qke.1 for ; Sun, 29 Mar 2020 19:33:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=bIwgeh9rHwo41HBlXUss+pfAH9DbFE6iCebsly3ZN4c=; b=w1Utm7e6d4/535TdQtPiMXksX4j1qcmln0qSp2Ce5ITm627q5dnSU8lnhyBq3uY9oE 0PhDmMsluIYgdTjcV+PSd7sVQ/WGe+IhJGHMYogCDZYqSvqJL1tsZLjyg/tB9D7Y4aYN zqy3An60oNrntByo8BqUBrC2oSWocnndGjLG8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=bIwgeh9rHwo41HBlXUss+pfAH9DbFE6iCebsly3ZN4c=; b=rk4qa2sZLcHQyUkQMnxqtZ13mHYsAmkVNzjxPCeuvdYgfo1TgGI5m4Uhais/wwGMRr CNBRNLtK4jr5R1PnNmerLlOK0AzdpgLIWXMJlvzrJ0rCqSYlEGEliVkcizqL70s7HK/p 4+IWgcxcux+hBAjiEuKVJmer8VXD5/ScrEQJ3aBsQXsu0Nuogk0aIIdfzAWCzdL+eNqW QSvdcTm/nLE29j3I8N7nA8kV1fAILecr1UEphEIWI8DBK0humUH2ASyqcxio9mrs0/iz tcHT5qSIHUd7RwBzqgphncI/6N0IjE9gPPMOqJYwMpJSW2YPYhNf41L3jzyolWk722lh Hr0w== X-Gm-Message-State: ANhLgQ20qqOkkQk+FyhLA8ew2msPV38bSJxPqgEW6MiJB9EJov0UXbIt Heh9e4WfuRBdi1jLN7hpHX7S+hPYLsU= X-Google-Smtp-Source: ADFU+vurXBFAw9FRqEBRvtnmRBiIAJYMQMQAx1nAenRxy7DRsubkevgiGpgtf0ZMZlIvcVQv3d7mpA== X-Received: by 2002:a37:a68e:: with SMTP id p136mr9993192qke.7.1585535629357; Sun, 29 Mar 2020 19:33:49 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id q15sm10030625qtj.83.2020.03.29.19.33.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Mar 2020 19:33:48 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Andrew Morton , Ingo Molnar , Josh Triplett , Lai Jiangshan , linux-mm@kvack.org, Mathieu Desnoyers , "Paul E. McKenney" , "Rafael J. Wysocki" , rcu@vger.kernel.org, Steven Rostedt , "Uladzislau Rezki (Sony)" Subject: [PATCH 18/18] rcu/tree: Make kvfree_rcu() tolerate any alignment Date: Sun, 29 Mar 2020 22:32:48 -0400 Message-Id: <20200330023248.164994-19-joel@joelfernandes.org> X-Mailer: git-send-email 2.26.0.rc2.310.g2932bb562d-goog In-Reply-To: <20200330023248.164994-1-joel@joelfernandes.org> References: <20200330023248.164994-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Handle cases where the the object being kvfree_rcu()'d is not aligned by 2-byte boundaries. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 311d216c7faa7..d6536374d12a9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2827,6 +2827,9 @@ struct kvfree_rcu_bulk_data { #define KVFREE_BULK_MAX_ENTR \ ((PAGE_SIZE - sizeof(struct kvfree_rcu_bulk_data)) / sizeof(void *)) +/* Encoding the offset of a fake rcu_head to indicate the head is a wrapper. */ +#define RCU_HEADLESS_KFREE BIT(31) + /** * struct kfree_rcu_cpu_work - single batch of kfree_rcu() requests * @rcu_work: Let queue_rcu_work() invoke workqueue handler after grace period @@ -2970,9 +2973,9 @@ static void kfree_rcu_work(struct work_struct *work) next = head->next; /* We tag the headless object, if so adjust offset. */ - headless = (((unsigned long) head - offset) & BIT(0)); + headless = !!(offset & RCU_HEADLESS_KFREE); if (headless) - offset -= 1; + offset &= ~(RCU_HEADLESS_KFREE); ptr = (void *) head - offset; debug_rcu_head_unqueue((struct rcu_head *)ptr); @@ -3221,7 +3224,7 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) * to the original allocated memory, that has to be freed as * well as dynamically attached wrapper/head. */ - func = (rcu_callback_t) (sizeof(unsigned long *) + 1); + func = (rcu_callback_t)(sizeof(unsigned long *) | RCU_HEADLESS_KFREE); } head->func = func; -- 2.26.0.rc2.310.g2932bb562d-goog