Merge remote-tracking branches 'asoc/fix/adsp', 'asoc/fix/arizona', 'asoc/fix/atmel...

[linux-drm-fsl-dcu.git] / drivers / staging / zsmalloc / zsmalloc-main.c

diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index 1a67537dbc5654be28e7d640f89d3fe3fd903e30..3b950e5a918f8c1a252aabc7da049e2732e2e15d 100644 (file)
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -430,7 +430,12 @@ static struct page *get_next_page(struct page *page)
        return next;
 }
 
-/* Encode <page, obj_idx> as a single handle value */
+/*
+ * Encode <page, obj_idx> as a single handle value.
+ * On hardware platforms with physical memory starting at 0x0 the pfn
+ * could be 0 so we ensure that the handle will never be 0 by adjusting the
+ * encoded obj_idx value before encoding.
+ */
 static void *obj_location_to_handle(struct page *page, unsigned long obj_idx)
 {
        unsigned long handle;
@@ -441,17 +446,21 @@ static void *obj_location_to_handle(struct page *page, unsigned long obj_idx)
        }
 
        handle = page_to_pfn(page) << OBJ_INDEX_BITS;
-       handle |= (obj_idx & OBJ_INDEX_MASK);
+       handle |= ((obj_idx + 1) & OBJ_INDEX_MASK);
 
        return (void *)handle;
 }
 
-/* Decode <page, obj_idx> pair from the given object handle */
+/*
+ * Decode <page, obj_idx> pair from the given object handle. We adjust the
+ * decoded obj_idx back to its original value since it was adjusted in
+ * obj_location_to_handle().
+ */
 static void obj_handle_to_location(unsigned long handle, struct page **page,
                                unsigned long *obj_idx)
 {
        *page = pfn_to_page(handle >> OBJ_INDEX_BITS);
-       *obj_idx = handle & OBJ_INDEX_MASK;
+       *obj_idx = (handle & OBJ_INDEX_MASK) - 1;
 }
 
 static unsigned long obj_idx_to_offset(struct page *page,