From: Jiang Liu <[email protected]> There are two global lists inf file drivers/acpi/pci_root.c. One is for registered acpi_pci_drivers, the other is for enumerated ACPI PCI root bridge objects. These two global lists may change dynamically when registering/deregistering acpi_pci_drivers or adding/removing ACPI PCI root bridge objects. So protect them by mutex lock and RCU list.
Signed-off-by: Jiang Liu <[email protected]> Signed-off-by: Yinghai Lu <[email protected]> --- drivers/acpi/pci_root.c | 87 ++++++++++++++++++++++++++++------------------ 1 files changed, 53 insertions(+), 34 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 9ba516b..f3402df 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -27,7 +27,8 @@ #include <linux/module.h> #include <linux/init.h> #include <linux/types.h> -#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/rculist.h> #include <linux/pm.h> #include <linux/pm_runtime.h> #include <linux/pci.h> @@ -71,6 +72,8 @@ static struct acpi_driver acpi_pci_root_driver = { }, }; +/* Lock to protect both acpi_pci_roots and acpi_pci_drivers lists */ +static DEFINE_MUTEX(acpi_pci_root_lock); static LIST_HEAD(acpi_pci_roots); static LIST_HEAD(acpi_pci_drivers); @@ -81,47 +84,48 @@ int acpi_pci_register_driver(struct acpi_pci_driver *driver) int n = 0; struct acpi_pci_root *root; + mutex_lock(&acpi_pci_root_lock); list_add_tail(&driver->node, &acpi_pci_drivers); - - if (!driver->add) - return 0; - - list_for_each_entry(root, &acpi_pci_roots, node) { - driver->add(root->device->handle); - n++; - } + if (driver->add) + list_for_each_entry_rcu(root, &acpi_pci_roots, node) { + driver->add(root->device->handle); + n++; + } + mutex_unlock(&acpi_pci_root_lock); return n; } - EXPORT_SYMBOL(acpi_pci_register_driver); void acpi_pci_unregister_driver(struct acpi_pci_driver *driver) { struct acpi_pci_root *root; + mutex_lock(&acpi_pci_root_lock); list_del(&driver->node); - - if (!driver->remove) - return; - - list_for_each_entry(root, &acpi_pci_roots, node) - driver->remove(root->device->handle); + if (driver->remove) + list_for_each_entry_rcu(root, &acpi_pci_roots, node) + driver->remove(root->device->handle); + mutex_unlock(&acpi_pci_root_lock); } - EXPORT_SYMBOL(acpi_pci_unregister_driver); acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus) { struct acpi_pci_root *root; + struct acpi_handle *handle = NULL; - list_for_each_entry(root, &acpi_pci_roots, node) + rcu_read_lock(); + list_for_each_entry_rcu(root, &acpi_pci_roots, node) if ((root->segment == (u16) seg) && - (root->secondary.start == (u16) bus)) - return root->device->handle; - return NULL; -} + (root->secondary.start == (u16) bus)) { + handle = root->device->handle; + break; + } + rcu_read_unlock(); + return handle; +} EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle); /** @@ -268,10 +272,15 @@ struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle) { struct acpi_pci_root *root; - list_for_each_entry(root, &acpi_pci_roots, node) { - if (root->device->handle == handle) + rcu_read_lock(); + list_for_each_entry_rcu(root, &acpi_pci_roots, node) { + if (root->device->handle == handle) { + rcu_read_unlock(); return root; + } } + rcu_read_unlock(); + return NULL; } EXPORT_SYMBOL_GPL(acpi_pci_find_root); @@ -459,7 +468,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { printk(KERN_ERR PREFIX "can't evaluate _SEG\n"); result = -ENODEV; - goto end; + goto out_free; } /* Check _CRS first, then _BBN. If no _BBN, default to zero. */ @@ -484,7 +493,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) else { printk(KERN_ERR PREFIX "can't evaluate _BBN\n"); result = -ENODEV; - goto end; + goto out_free; } } @@ -508,8 +517,8 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) * TBD: Need PCI interface for enumeration/configuration of roots. */ - /* TBD: Locking */ - list_add_tail(&root->node, &acpi_pci_roots); + mutex_lock(&acpi_pci_root_lock); + list_add_tail_rcu(&root->node, &acpi_pci_roots); printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n", acpi_device_name(device), acpi_device_bid(device), @@ -528,7 +537,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) "Bus %04x:%02x not present in PCI namespace\n", root->segment, (unsigned int)root->secondary.start); result = -ENODEV; - goto end; + goto out_del_root; } /* @@ -538,7 +547,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) */ result = acpi_pci_bind_root(device); if (result) - goto end; + goto out_del_root; /* * PCI Routing Table @@ -614,11 +623,15 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) if (device->wakeup.flags.run_wake) device_set_run_wake(root->bus->bridge, true); + mutex_unlock(&acpi_pci_root_lock); + return 0; -end: - if (!list_empty(&root->node)) - list_del(&root->node); +out_del_root: + list_del_rcu(&root->node); + mutex_unlock(&acpi_pci_root_lock); + synchronize_rcu(); +out_free: kfree(root); return result; } @@ -628,11 +641,13 @@ static int acpi_pci_root_start(struct acpi_device *device) struct acpi_pci_root *root = acpi_driver_data(device); struct acpi_pci_driver *driver; + mutex_lock(&acpi_pci_root_lock); list_for_each_entry(driver, &acpi_pci_drivers, node) if (driver->add) driver->add(device->handle); pci_bus_add_devices(root->bus); + mutex_unlock(&acpi_pci_root_lock); return 0; } @@ -642,6 +657,8 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type) struct acpi_pci_root *root = acpi_driver_data(device); struct acpi_pci_driver *driver; + mutex_lock(&acpi_pci_root_lock); + list_for_each_entry(driver, &acpi_pci_drivers, node) if (driver->remove) driver->remove(root->device->handle); @@ -661,7 +678,9 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type) pci_stop_and_remove_bus(root->bus); out: - list_del(&root->node); + list_del_rcu(&root->node); + mutex_unlock(&acpi_pci_root_lock); + synchronize_rcu(); kfree(root); return 0; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
