1 files changed, 71 insertions, 29 deletions

diff --git a/drivers/acpi/acpica/uttrack.c b/drivers/acpi/acpica/uttrack.c
index 79f311c3d1c4..a424a9e3fea4 100644
--- a/drivers/acpi/acpica/uttrack.c
+++ b/drivers/acpi/acpica/uttrack.c
@@ -61,7 +61,9 @@
 ACPI_MODULE_NAME("uttrack")
 
 /* Local prototypes */
-static struct acpi_debug_mem_block *acpi_ut_find_allocation(void *allocation);
+static struct acpi_debug_mem_block *acpi_ut_find_allocation(struct
+                                                            acpi_debug_mem_block
+                                                            *allocation);
 
 static acpi_status
 acpi_ut_track_allocation(struct acpi_debug_mem_block *address,
@@ -263,31 +265,61 @@ acpi_ut_free_and_track(void *allocation,
  *
  * PARAMETERS:  allocation              - Address of allocated memory
  *
- * RETURN:      A list element if found; NULL otherwise.
+ * RETURN:      Three cases:
+ *              1) List is empty, NULL is returned.
+ *              2) Element was found. Returns Allocation parameter.
+ *              3) Element was not found. Returns position where it should be
+ *                  inserted into the list.
  *
  * DESCRIPTION: Searches for an element in the global allocation tracking list.
+ *              If the element is not found, returns the location within the
+ *              list where the element should be inserted.
+ *
+ *              Note: The list is ordered by larger-to-smaller addresses.
+ *
+ *              This global list is used to detect memory leaks in ACPICA as
+ *              well as other issues such as an attempt to release the same
+ *              internal object more than once. Although expensive as far
+ *              as cpu time, this list is much more helpful for finding these
+ *              types of issues than using memory leak detectors outside of
+ *              the ACPICA code.
  *
  ******************************************************************************/
 
-static struct acpi_debug_mem_block *acpi_ut_find_allocation(void *allocation)
+static struct acpi_debug_mem_block *acpi_ut_find_allocation(struct
+                                                            acpi_debug_mem_block
+                                                            *allocation)
 {
         struct acpi_debug_mem_block *element;
 
-        ACPI_FUNCTION_ENTRY();
-
         element = acpi_gbl_global_list->list_head;
+        if (!element) {
+                return (NULL);
+        }
+
+        /*
+         * Search for the address.
+         *
+         * Note: List is ordered by larger-to-smaller addresses, on the
+         * assumption that a new allocation usually has a larger address
+         * than previous allocations.
+         */
+        while (element > allocation) {
 
-        /* Search for the address. */
+                /* Check for end-of-list */
 
-        while (element) {
-                if (element == allocation) {
+                if (!element->next) {
                         return (element);
                 }
 
                 element = element->next;
         }
 
-        return (NULL);
+        if (element == allocation) {
+                return (element);
+        }
+
+        return (element->previous);
 }
 
 /*******************************************************************************
@@ -301,7 +333,7 @@ static struct acpi_debug_mem_block *acpi_ut_find_allocation(void *allocation)
  *              module              - Source file name of caller
  *              line                - Line number of caller
  *
- * RETURN:      None.
+ * RETURN:      Status
  *
  * DESCRIPTION: Inserts an element into the global allocation tracking list.
  *
@@ -330,22 +362,18 @@ acpi_ut_track_allocation(struct acpi_debug_mem_block *allocation,
         }
 
         /*
-         * Search list for this address to make sure it is not already on the list.
-         * This will catch several kinds of problems.
+         * Search the global list for this address to make sure it is not
+         * already present. This will catch several kinds of problems.
          */
         element = acpi_ut_find_allocation(allocation);
-        if (element) {
+        if (element == allocation) {
                 ACPI_ERROR((AE_INFO,
-                            "UtTrackAllocation: Allocation already present in list! (%p)",
+                            "UtTrackAllocation: Allocation (%p) already present in global list!",
                             allocation));
-
-                ACPI_ERROR((AE_INFO, "Element %p Address %p",
-                            element, allocation));
-
                 goto unlock_and_exit;
         }
 
-        /* Fill in the instance data. */
+        /* Fill in the instance data */
 
         allocation->size = (u32)size;
         allocation->alloc_type = alloc_type;
@@ -355,17 +383,31 @@ acpi_ut_track_allocation(struct acpi_debug_mem_block *allocation,
         ACPI_STRNCPY(allocation->module, module, ACPI_MAX_MODULE_NAME);
         allocation->module[ACPI_MAX_MODULE_NAME - 1] = 0;
 
-        /* Insert at list head */
+        if (!element) {
 
-        if (mem_list->list_head) {
-                ((struct acpi_debug_mem_block *)(mem_list->list_head))->
-                    previous = allocation;
-        }
+                /* Insert at list head */
+
+                if (mem_list->list_head) {
+                        ((struct acpi_debug_mem_block *)(mem_list->list_head))->
+                            previous = allocation;
+                }
+
+                allocation->next = mem_list->list_head;
+                allocation->previous = NULL;
 
-        allocation->next = mem_list->list_head;
-        allocation->previous = NULL;
+                mem_list->list_head = allocation;
+        } else {
+                /* Insert after element */
+
+                allocation->next = element->next;
+                allocation->previous = element;
+
+                if (element->next) {
+                        (element->next)->previous = allocation;
+                }
 
-        mem_list->list_head = allocation;
+                element->next = allocation;
+        }
 
       unlock_and_exit:
         status = acpi_ut_release_mutex(ACPI_MTX_MEMORY);
@@ -381,7 +423,7 @@ acpi_ut_track_allocation(struct acpi_debug_mem_block *allocation,
  *              module              - Source file name of caller
  *              line                - Line number of caller
  *
- * RETURN:
+ * RETURN:      Status
  *
  * DESCRIPTION: Deletes an element from the global allocation tracking list.
  *
@@ -443,7 +485,7 @@ acpi_ut_remove_allocation(struct acpi_debug_mem_block *allocation,
  *
  * FUNCTION:    acpi_ut_dump_allocation_info
  *
- * PARAMETERS:
+ * PARAMETERS:  None
  *
  * RETURN:      None
  *