From bfee26dba0f373ebe4e6f0b293d078b02f9f7f69 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 26 Jan 2013 00:27:44 +0100 Subject: ACPI / scan: Make it clear that acpi_bus_trim() cannot fail Since acpi_bus_trim() cannot fail, change its definition to a void function, so that its callers don't check the return value in vain and update the callers. Signed-off-by: Rafael J. Wysocki Acked-by: Yinghai Lu Acked-by: Yasuaki Ishimatsu Acked-by: Toshi Kani --- drivers/acpi/scan.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 7c43bdc36abc..d37f290be44c 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -127,13 +127,8 @@ void acpi_bus_hot_remove_device(void *context) ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Hot-removing device %s...\n", dev_name(&device->dev))); - if (acpi_bus_trim(device)) { - printk(KERN_ERR PREFIX - "Removing device failed\n"); - goto err_out; - } - - /* device has been freed */ + acpi_bus_trim(device); + /* Device node has been released. */ device = NULL; /* power off device */ @@ -1631,7 +1626,7 @@ static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used, return AE_OK; } -int acpi_bus_trim(struct acpi_device *start) +void acpi_bus_trim(struct acpi_device *start) { /* * Execute acpi_bus_device_detach() as a post-order callback to detach @@ -1647,7 +1642,6 @@ int acpi_bus_trim(struct acpi_device *start) acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL, acpi_bus_remove, NULL, NULL); acpi_bus_remove(start->handle, 0, NULL, NULL); - return 0; } EXPORT_SYMBOL_GPL(acpi_bus_trim); -- cgit v1.2.3 From c511cc1990bbc263c3f8a2ef4d7d613a3b40ffe2 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 27 Jan 2013 21:17:29 +0100 Subject: ACPI / scan: Make namespace scanning and trimming mutually exclusive There is no guarantee that acpi_bus_scan() and acpi_bus_trim() will not be run in parallel for the same scope of the ACPI namespace, which may lead to a great deal of confusion, so introduce a new mutex to prevent that from happening. Signed-off-by: Rafael J. Wysocki Acked-by: Yinghai Lu --- drivers/acpi/scan.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index d37f290be44c..43754655c156 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_platform_device_ids[] = { static LIST_HEAD(acpi_device_list); static LIST_HEAD(acpi_bus_id_list); +static DEFINE_MUTEX(acpi_scan_lock); DEFINE_MUTEX(acpi_device_lock); LIST_HEAD(acpi_wakeup_device_list); @@ -1587,19 +1588,22 @@ static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used, int acpi_bus_scan(acpi_handle handle) { void *device = NULL; + int error = 0; + + mutex_lock(&acpi_scan_lock); if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device))) acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, acpi_bus_check_add, NULL, NULL, &device); if (!device) - return -ENODEV; - - if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL))) + error = -ENODEV; + else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL))) acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, acpi_bus_device_attach, NULL, NULL, NULL); - return 0; + mutex_unlock(&acpi_scan_lock); + return error; } EXPORT_SYMBOL(acpi_bus_scan); @@ -1628,6 +1632,8 @@ static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used, void acpi_bus_trim(struct acpi_device *start) { + mutex_lock(&acpi_scan_lock); + /* * Execute acpi_bus_device_detach() as a post-order callback to detach * all ACPI drivers from the device nodes being removed. @@ -1642,6 +1648,8 @@ void acpi_bus_trim(struct acpi_device *start) acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL, acpi_bus_remove, NULL, NULL); acpi_bus_remove(start->handle, 0, NULL, NULL); + + mutex_unlock(&acpi_scan_lock); } EXPORT_SYMBOL_GPL(acpi_bus_trim); -- cgit v1.2.3