Mailing List Archive

Rather than storing the reference acpi_device pointers in an ACPI-ID-
indexed array (and having a bogus BUG_ON() check on a platform provided
value), use a radix tree instead.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -513,7 +513,14 @@ static int acpi_processor_get_info(struc
return 0;
}

-static void *processor_device_array[NR_ACPI_CPUS];
+#ifndef CONFIG_XEN
+static void *processor_device_array[NR_CPUS];
+#else
+#include <linux/mutex.h>
+#include <linux/radix-tree.h>
+static DEFINE_MUTEX(processor_device_mutex);
+static RADIX_TREE(processor_device_tree, GFP_KERNEL);
+#endif

static int acpi_processor_start(struct acpi_device *device)
{
@@ -541,9 +548,20 @@ static int __cpuinit acpi_processor_add(
* Don't trust it blindly
*/
#ifdef CONFIG_XEN
- BUG_ON(pr->acpi_id >= NR_ACPI_CPUS);
- if (processor_device_array[pr->acpi_id] != NULL &&
- processor_device_array[pr->acpi_id] != (void *)device) {
+ mutex_lock(&processor_device_mutex);
+ result = radix_tree_insert(&processor_device_tree,
+ pr->acpi_id, device);
+ switch (result) {
+ default:
+ goto end_unlock;
+ case -EEXIST:
+ if (radix_tree_lookup(&processor_device_tree,
+ pr->acpi_id) == device) {
+ case 0:
+ mutex_unlock(&processor_device_mutex);
+ break;
+ }
+ mutex_unlock(&processor_device_mutex);
#else
if (processor_device_array[pr->id] != NULL &&
processor_device_array[pr->id] != (void *)device) {
@@ -553,14 +571,11 @@ static int __cpuinit acpi_processor_add(
return -ENODEV;
}
#ifdef CONFIG_XEN
- processor_device_array[pr->acpi_id] = (void *)device;
if (pr->id != -1)
- processors[pr->id] = pr;
#else
processor_device_array[pr->id] = (void *)device;
-
- processors[pr->id] = pr;
#endif /* CONFIG_XEN */
+ processors[pr->id] = pr;

result = acpi_processor_add_fs(device);
if (result)
@@ -602,6 +617,14 @@ err_thermal_unregister:
}

end:
+#ifdef CONFIG_XEN
+ mutex_lock(&processor_device_mutex);
+ if (radix_tree_lookup(&processor_device_tree,
+ pr->acpi_id) == device)
+ radix_tree_delete(&processor_device_tree, pr->acpi_id);
+ end_unlock:
+ mutex_unlock(&processor_device_mutex);
+#endif

return result;
}
@@ -692,10 +715,8 @@ static int acpi_processor_remove(struct

#ifdef CONFIG_XEN
if (pr->id != -1)
- processors[pr->id] = NULL;
-#else
+#endif
processors[pr->id] = NULL;
-#endif /* CONFIG_XEN */


kfree(pr);
@@ -992,6 +1013,30 @@ static void __exit acpi_processor_exit(v

remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir);

+#ifdef CONFIG_XEN
+ {
+ struct acpi_device *dev;
+ unsigned int idx = 0;
+
+ while (radix_tree_gang_lookup(&processor_device_tree,
+ (void **)&dev, idx, 1)) {
+ struct acpi_processor *pr = acpi_driver_data(dev);
+
+ /* prevent live lock */
+ if (pr->acpi_id < idx) {
+ printk(KERN_WARNING PREFIX "ID %u unexpected"
+ " (less than %u); leaking memory\n",
+ pr->acpi_id, idx);
+ break;
+ }
+ idx = pr->acpi_id;
+ radix_tree_delete(&processor_device_tree, idx);
+ if (!++idx)
+ break;
+ }
+ }
+#endif
+
return;
}

--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -24,12 +24,6 @@
#define ACPI_TSD_REV0_REVISION 0 /* Support for _PSD as in ACPI 3.0 */
#define ACPI_TSD_REV0_ENTRIES 5

-#ifdef CONFIG_XEN
-#define NR_ACPI_CPUS (NR_CPUS < 256 ? 256 : NR_CPUS)
-#else
-#define NR_ACPI_CPUS NR_CPUS
-#endif /* CONFIG_XEN */
-
/*
* Types of coordination defined in ACPI 3.0. Same macros can be used across
* P, C and T states