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-rw-r--r--mm/nommu.c30
1 files changed, 26 insertions, 4 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index dca93fcb8b7a..3abd0845bda4 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -104,21 +104,43 @@ EXPORT_SYMBOL(vmtruncate);
unsigned int kobjsize(const void *objp)
{
struct page *page;
+ int order = 0;
/*
* If the object we have should not have ksize performed on it,
* return size of 0
*/
- if (!objp || (unsigned long)objp >= memory_end || !((page = virt_to_page(objp))))
+ if (!objp)
return 0;
+ if ((unsigned long)objp >= memory_end)
+ return 0;
+
+ page = virt_to_head_page(objp);
+ if (!page)
+ return 0;
+
+ /*
+ * If the allocator sets PageSlab, we know the pointer came from
+ * kmalloc().
+ */
if (PageSlab(page))
return ksize(objp);
- BUG_ON(page->index < 0);
- BUG_ON(page->index >= MAX_ORDER);
+ /*
+ * The ksize() function is only guaranteed to work for pointers
+ * returned by kmalloc(). So handle arbitrary pointers, that we expect
+ * always to be compound pages, here.
+ */
+ if (PageCompound(page))
+ order = compound_order(page);
- return (PAGE_SIZE << page->index);
+ /*
+ * Finally, handle arbitrary pointers that don't set PageSlab.
+ * Default to 0-order in the case when we're unable to ksize()
+ * the object.
+ */
+ return PAGE_SIZE << order;
}
/*
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