From patchwork Tue Jul 30 13:29:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 170068 Delivered-To: patch@linaro.org Received: by 2002:a92:512:0:0:0:0:0 with SMTP id q18csp2647406ile; Tue, 30 Jul 2019 06:32:24 -0700 (PDT) X-Google-Smtp-Source: APXvYqwGghKud/IrQMcPFLktab2yNp9sIPctSaveI09otUf1CB9FqCTogoT/hJ/SCgjdzAm+lGWR X-Received: by 2002:a62:1d11:: with SMTP id d17mr42278639pfd.249.1564493544301; Tue, 30 Jul 2019 06:32:24 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1564493544; cv=none; d=google.com; s=arc-20160816; b=CwSG3Hmcg9pTkqP3+3p1Gt7HsqfskZid6KLyHOK0u4wzLZZ2YRqtP+9lHN65DU8B0b 0qLNNWSOHSzMuHLR6JszOx192JYX+lPNUW6mDTUOiMIeprQDfJ0LI9CUatsCQVCvIT6I X1Rg0OeYdrunTqowP6BmuByI/iYcaU42peXwsdVcIbKHng/zlwykpz7nBIpnx4Y/6PqC 02ctZ/DGVWpe/kGzFQSwGm9927Eu3y899CdsTCMKNEV9OebEx3ealAwObU8Y2OKv/NyQ IA2bB/1t6ZsIoVU5MNFX3UNqf6PmnJYiOWaV8/ye5HIzN3DVHyHOmfa9gljpdqo3ovhL msfw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from; bh=37gtWyQ8ScIS6gDA4SZcPlvqMu2w3UJOF3Y7LabbgXI=; b=gBcXkbStQo8QbjPeMg7fvrIWJn5XYBRqGXGw9pYh5n3u1ZNMbSFmAMGuNPJs2FTNaN JViDA3m9JNkBVtJnZYi/KzPZ0fEcXSLP2EgUjEzGgPDBGEyYNJjwmeFyjVoqlBSjq+lx SU0xI4HzyPxOwNicUtxAusHNPq9rzFOdVqnWQ8cOSW57tj0/ljxrQUOijt1mioIOczqX zE5RH5tDQo6lDd/ce1rbAg6WW0xZN26m7vnGnL6GfcaG1/K14F0cg02JIeG1BLNGhQcG 22MoHvJd3+ijTawkGA+xdGyqs1F63bvcty9wGvoYUkeP0zWDavXfTJdHrn+tCSqiAO4z G60Q== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id r11si30399005pjq.108.2019.07.30.06.32.24; Tue, 30 Jul 2019 06:32:24 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731108AbfG3NcX (ORCPT + 29 others); Tue, 30 Jul 2019 09:32:23 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:3222 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726382AbfG3NcD (ORCPT ); Tue, 30 Jul 2019 09:32:03 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 483AFB7D026684F4B264; Tue, 30 Jul 2019 21:32:00 +0800 (CST) Received: from localhost.localdomain (10.67.212.75) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Tue, 30 Jul 2019 21:31:54 +0800 From: John Garry To: CC: , , , , , , John Garry Subject: [PATCH v4 1/5] lib: logic_pio: Fix RCU usage Date: Tue, 30 Jul 2019 21:29:52 +0800 Message-ID: <1564493396-92195-2-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1564493396-92195-1-git-send-email-john.garry@huawei.com> References: <1564493396-92195-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.212.75] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The traversing of io_range_list with list_for_each_entry_rcu() is not properly protected by rcu_read_lock() and rcu_read_unlock(), so add them. These functions mark the critical section scope where the list is protected for the reader, it cannot be "reclaimed". Any updater - in this case, the logical PIO registration functions - cannot update the list until the reader exits this critical section. In addition, the list traversing used in logic_pio_register_range() does not need to use the rcu variant. This is because we are already using io_range_mutex to guarantee mutual exclusion from mutating the list. Cc: stable@vger.kernel.org Fixes: 031e3601869c ("lib: Add generic PIO mapping method") Signed-off-by: John Garry --- lib/logic_pio.c | 49 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 35 insertions(+), 14 deletions(-) -- 2.17.1 diff --git a/lib/logic_pio.c b/lib/logic_pio.c index feea48fd1a0d..761296376fbc 100644 --- a/lib/logic_pio.c +++ b/lib/logic_pio.c @@ -46,7 +46,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range) end = new_range->hw_start + new_range->size; mutex_lock(&io_range_mutex); - list_for_each_entry_rcu(range, &io_range_list, list) { + list_for_each_entry(range, &io_range_list, list) { if (range->fwnode == new_range->fwnode) { /* range already there */ goto end_register; @@ -108,26 +108,38 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range) */ struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode) { - struct logic_pio_hwaddr *range; + struct logic_pio_hwaddr *range, *found_range = NULL; + rcu_read_lock(); list_for_each_entry_rcu(range, &io_range_list, list) { - if (range->fwnode == fwnode) - return range; + if (range->fwnode == fwnode) { + found_range = range; + break; + } } - return NULL; + rcu_read_unlock(); + + return found_range; } /* Return a registered range given an input PIO token */ static struct logic_pio_hwaddr *find_io_range(unsigned long pio) { - struct logic_pio_hwaddr *range; + struct logic_pio_hwaddr *range, *found_range = NULL; + rcu_read_lock(); list_for_each_entry_rcu(range, &io_range_list, list) { - if (in_range(pio, range->io_start, range->size)) - return range; + if (in_range(pio, range->io_start, range->size)) { + found_range = range; + break; + } } - pr_err("PIO entry token %lx invalid\n", pio); - return NULL; + rcu_read_unlock(); + + if (!found_range) + pr_err("PIO entry token 0x%lx invalid\n", pio); + + return found_range; } /** @@ -180,14 +192,23 @@ unsigned long logic_pio_trans_cpuaddr(resource_size_t addr) { struct logic_pio_hwaddr *range; + rcu_read_lock(); list_for_each_entry_rcu(range, &io_range_list, list) { if (range->flags != LOGIC_PIO_CPU_MMIO) continue; - if (in_range(addr, range->hw_start, range->size)) - return addr - range->hw_start + range->io_start; + if (in_range(addr, range->hw_start, range->size)) { + unsigned long cpuaddr; + + cpuaddr = addr - range->hw_start + range->io_start; + + rcu_read_unlock(); + return cpuaddr; + } } - pr_err("addr %llx not registered in io_range_list\n", - (unsigned long long) addr); + rcu_read_unlock(); + + pr_err("addr %pa not registered in io_range_list\n", &addr); + return ~0UL; }