From patchwork Fri Jan 10 14:24:41 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 309287 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CF7CD2C009B for ; Sat, 11 Jan 2014 01:18:21 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757402AbaAJOSP (ORCPT ); Fri, 10 Jan 2014 09:18:15 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:61027 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752185AbaAJOQV (ORCPT ); Fri, 10 Jan 2014 09:16:21 -0500 Received: from afdq137.neoplus.adsl.tpnet.pl [95.49.94.137] (HELO vostro.rjw.lan) by serwer1319399.home.pl [79.96.170.134] with SMTP (IdeaSmtpServer v0.80) id 1fd864a2aa0fb50f; Fri, 10 Jan 2014 15:16:19 +0100 From: "Rafael J. Wysocki" To: Bjorn Helgaas Cc: Yinghai Lu , "Rafael J. Wysocki" , Gu Zheng , Guo Chao , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Mika Westerberg , Myron Stowe , Benjamin Herrenschmidt , linux-scsi@vger.kernel.org, Matthew Garrett , Konrad Rzeszutek Wilk Subject: [PATCH 3/9] ACPI / hotplug / PCI: Use global PCI rescan-remove locking Date: Fri, 10 Jan 2014 15:24:41 +0100 Message-ID: <1889108.hSyl0lYrWr@vostro.rjw.lan> User-Agent: KMail/4.11.3 (Linux/3.13.0-rc6+; KDE/4.11.3; x86_64; ; ) In-Reply-To: <20440867.YaQfKrcfsQ@vostro.rjw.lan> References: <1385429290-25397-1-git-send-email-yinghai@kernel.org> <1992931.Zv6xBcN8V4@vostro.rjw.lan> <20440867.YaQfKrcfsQ@vostro.rjw.lan> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Rafael J. Wysocki Multiple race conditions are possible between the ACPI-based PCI hotplug (ACPIPHP) and the generic PCI bus rescan and device removal that can be triggered via sysfs. To avoid those race conditions make the ACPIPHP code use global PCI rescan-remove locking. Signed-off-by: Rafael J. Wysocki --- drivers/pci/hotplug/acpiphp.h | 5 +++- drivers/pci/hotplug/acpiphp_core.c | 2 - drivers/pci/hotplug/acpiphp_glue.c | 43 ++++++++++++++++++++++++++++++++----- 3 files changed, 43 insertions(+), 7 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-pm/drivers/pci/hotplug/acpiphp.h =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp.h +++ linux-pm/drivers/pci/hotplug/acpiphp.h @@ -77,6 +77,8 @@ struct acpiphp_bridge { /* PCI-to-PCI bridge device */ struct pci_dev *pci_dev; + + bool is_going_away; }; @@ -150,6 +152,7 @@ struct acpiphp_attention_info /* slot flags */ #define SLOT_ENABLED (0x00000001) +#define SLOT_IS_GOING_AWAY (0x00000002) /* function flags */ @@ -169,7 +172,7 @@ void acpiphp_unregister_hotplug_slot(str typedef int (*acpiphp_callback)(struct acpiphp_slot *slot, void *data); int acpiphp_enable_slot(struct acpiphp_slot *slot); -int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot); +int acpiphp_disable_slot(struct acpiphp_slot *slot); u8 acpiphp_get_power_status(struct acpiphp_slot *slot); u8 acpiphp_get_attention_status(struct acpiphp_slot *slot); u8 acpiphp_get_latch_status(struct acpiphp_slot *slot); Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -432,6 +432,7 @@ static void cleanup_bridge(struct acpiph pr_err("failed to remove notify handler\n"); } } + slot->flags |= SLOT_IS_GOING_AWAY; if (slot->slot) acpiphp_unregister_hotplug_slot(slot); } @@ -439,6 +440,8 @@ static void cleanup_bridge(struct acpiph mutex_lock(&bridge_mutex); list_del(&bridge->list); mutex_unlock(&bridge_mutex); + + bridge->is_going_away = true; } /** @@ -757,6 +760,10 @@ static void acpiphp_check_bridge(struct { struct acpiphp_slot *slot; + /* Bail out if the bridge is going away. */ + if (bridge->is_going_away) + return; + list_for_each_entry(slot, &bridge->slots, node) { struct pci_bus *bus = slot->bus; struct pci_dev *dev, *tmp; @@ -827,6 +834,8 @@ void acpiphp_check_host_bridge(acpi_hand } } +static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot); + static void hotplug_event(acpi_handle handle, u32 type, void *data) { struct acpiphp_context *context = data; @@ -856,6 +865,9 @@ static void hotplug_event(acpi_handle ha } else { struct acpiphp_slot *slot = func->slot; + if (slot->flags & SLOT_IS_GOING_AWAY) + break; + mutex_lock(&slot->crit_sect); enable_slot(slot); mutex_unlock(&slot->crit_sect); @@ -871,6 +883,9 @@ static void hotplug_event(acpi_handle ha struct acpiphp_slot *slot = func->slot; int ret; + if (slot->flags & SLOT_IS_GOING_AWAY) + break; + /* * Check if anything has changed in the slot and rescan * from the parent if that's the case. @@ -900,9 +915,11 @@ static void hotplug_event_work(void *dat acpi_handle handle = context->handle; acpi_scan_lock_acquire(); + pci_lock_rescan_remove(); hotplug_event(handle, type, context); + pci_unlock_rescan_remove(); acpi_scan_lock_release(); acpi_evaluate_hotplug_ost(handle, type, ACPI_OST_SC_SUCCESS, NULL); put_bridge(context->func.parent); @@ -1070,12 +1087,19 @@ void acpiphp_remove_slots(struct pci_bus */ int acpiphp_enable_slot(struct acpiphp_slot *slot) { + pci_lock_rescan_remove(); + + if (slot->flags & SLOT_IS_GOING_AWAY) + return -ENODEV; + mutex_lock(&slot->crit_sect); /* configure all functions */ if (!(slot->flags & SLOT_ENABLED)) enable_slot(slot); mutex_unlock(&slot->crit_sect); + + pci_unlock_rescan_remove(); return 0; } @@ -1083,10 +1107,12 @@ int acpiphp_enable_slot(struct acpiphp_s * acpiphp_disable_and_eject_slot - power off and eject slot * @slot: ACPI PHP slot */ -int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot) +static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot) { struct acpiphp_func *func; - int retval = 0; + + if (slot->flags & SLOT_IS_GOING_AWAY) + return -ENODEV; mutex_lock(&slot->crit_sect); @@ -1104,9 +1130,18 @@ int acpiphp_disable_and_eject_slot(struc } mutex_unlock(&slot->crit_sect); - return retval; + return 0; } +int acpiphp_disable_slot(struct acpiphp_slot *slot) +{ + int ret; + + pci_lock_rescan_remove(); + ret = acpiphp_disable_and_eject_slot(slot); + pci_unlock_rescan_remove(); + return ret; +} /* * slot enabled: 1 @@ -1117,7 +1152,6 @@ u8 acpiphp_get_power_status(struct acpip return (slot->flags & SLOT_ENABLED); } - /* * latch open: 1 * latch closed: 0 @@ -1127,7 +1161,6 @@ u8 acpiphp_get_latch_status(struct acpip return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI); } - /* * adapter presence : 1 * absence : 0 Index: linux-pm/drivers/pci/hotplug/acpiphp_core.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_core.c +++ linux-pm/drivers/pci/hotplug/acpiphp_core.c @@ -156,7 +156,7 @@ static int disable_slot(struct hotplug_s pr_debug("%s - physical_slot = %s\n", __func__, slot_name(slot)); /* disable the specified slot */ - return acpiphp_disable_and_eject_slot(slot->acpi_slot); + return acpiphp_disable_slot(slot->acpi_slot); }