ACPICA: fix leak of acpi_os_validate_address

http://bugzilla.kernel.org/show_bug.cgi?id=13620

If the dynamic region is created and added to resource list over and over again,
it has the potential to be a memory leak by growing the list every time.

This patch fixes the memory leak, as below

1) add a new field "count" to struct acpi_res_list.

   When inserting, if the region(addr, len) is already in the resource
   list, we just increase "count", otherwise, the region is inserted
   with count=1.

   When deleting, the "count" is decreased, if it's decreased to 0,
   the region is deleted from the resource list.

   With "count", the region with same address and length can only be
   inserted to the resource list once, so prevent potential memory leak.

2) add a new function acpi_os_invalidate_address, which is called when
   region is deleted.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 91 insertions, 3 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 5691f165a952..c5b4f1ed9b71 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -88,6 +88,7 @@ struct acpi_res_list {
 	char name[5];   /* only can have a length of 4 chars, make use of this
 			   one instead of res->name, no need to kalloc then */
 	struct list_head resource_list;
+	int count;
 };
 
 static LIST_HEAD(resource_list_head);
@@ -1358,6 +1359,89 @@ acpi_os_validate_interface (char *interface)
 	return AE_SUPPORT;
 }
 
+static inline int acpi_res_list_add(struct acpi_res_list *res)
+{
+	struct acpi_res_list *res_list_elem;
+
+	list_for_each_entry(res_list_elem, &resource_list_head,
+			    resource_list) {
+
+		if (res->resource_type == res_list_elem->resource_type &&
+		    res->start == res_list_elem->start &&
+		    res->end == res_list_elem->end) {
+
+			/*
+			 * The Region(addr,len) already exist in the list,
+			 * just increase the count
+			 */
+
+			res_list_elem->count++;
+			return 0;
+		}
+	}
+
+	res->count = 1;
+	list_add(&res->resource_list, &resource_list_head);
+	return 1;
+}
+
+static inline void acpi_res_list_del(struct acpi_res_list *res)
+{
+	struct acpi_res_list *res_list_elem;
+
+	list_for_each_entry(res_list_elem, &resource_list_head,
+			    resource_list) {
+
+		if (res->resource_type == res_list_elem->resource_type &&
+		    res->start == res_list_elem->start &&
+		    res->end == res_list_elem->end) {
+
+			/*
+			 * If the res count is decreased to 0,
+			 * remove and free it
+			 */
+
+			if (--res_list_elem->count == 0) {
+				list_del(&res_list_elem->resource_list);
+				kfree(res_list_elem);
+			}
+			return;
+		}
+	}
+}
+
+acpi_status
+acpi_os_invalidate_address(
+    u8                   space_id,
+    acpi_physical_address   address,
+    acpi_size               length)
+{
+	struct acpi_res_list res;
+
+	switch (space_id) {
+	case ACPI_ADR_SPACE_SYSTEM_IO:
+	case ACPI_ADR_SPACE_SYSTEM_MEMORY:
+		/* Only interference checks against SystemIO and SytemMemory
+		   are needed */
+		res.start = address;
+		res.end = address + length - 1;
+		res.resource_type = space_id;
+		spin_lock(&acpi_res_lock);
+		acpi_res_list_del(&res);
+		spin_unlock(&acpi_res_lock);
+		break;
+	case ACPI_ADR_SPACE_PCI_CONFIG:
+	case ACPI_ADR_SPACE_EC:
+	case ACPI_ADR_SPACE_SMBUS:
+	case ACPI_ADR_SPACE_CMOS:
+	case ACPI_ADR_SPACE_PCI_BAR_TARGET:
+	case ACPI_ADR_SPACE_DATA_TABLE:
+	case ACPI_ADR_SPACE_FIXED_HARDWARE:
+		break;
+	}
+	return AE_OK;
+}
+
 /******************************************************************************
  *
  * FUNCTION:    acpi_os_validate_address
@@ -1382,6 +1466,7 @@ acpi_os_validate_address (
     char *name)
 {
 	struct acpi_res_list *res;
+	int added;
 	if (acpi_enforce_resources == ENFORCE_RESOURCES_NO)
 		return AE_OK;
 
@@ -1399,14 +1484,17 @@ acpi_os_validate_address (
 		res->end = address + length - 1;
 		res->resource_type = space_id;
 		spin_lock(&acpi_res_lock);
-		list_add(&res->resource_list, &resource_list_head);
+		added = acpi_res_list_add(res);
 		spin_unlock(&acpi_res_lock);
-		pr_debug("Added %s resource: start: 0x%llx, end: 0x%llx, "
-			 "name: %s\n", (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+		pr_debug("%s %s resource: start: 0x%llx, end: 0x%llx, "
+			 "name: %s\n", added ? "Added" : "Already exist",
+			 (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
 			 ? "SystemIO" : "System Memory",
 			 (unsigned long long)res->start,
 			 (unsigned long long)res->end,
 			 res->name);
+		if (!added)
+			kfree(res);
 		break;
 	case ACPI_ADR_SPACE_PCI_CONFIG:
 	case ACPI_ADR_SPACE_EC: