kmap_atomic: make kunmap_atomic() harder to misuse

[pandora-kernel.git] / include / linux / highmem.h

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index caafd05..67460f0 100644 (file)
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -2,6 +2,7 @@
 #define _LINUX_HIGHMEM_H
 
 #include <linux/fs.h>
+#include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 
@@ -72,7 +73,7 @@ static inline void *kmap_atomic(struct page *page, enum km_type idx)
 }
 #define kmap_atomic_prot(page, idx, prot)      kmap_atomic(page, idx)
 
-#define kunmap_atomic(addr, idx)       do { pagefault_enable(); } while (0)
+#define kunmap_atomic_notypecheck(addr, idx)   do { pagefault_enable(); } while (0)
 #define kmap_atomic_pfn(pfn, idx)      kmap_atomic(pfn_to_page(pfn), (idx))
 #define kmap_atomic_to_page(ptr)       virt_to_page(ptr)
 
@@ -81,6 +82,13 @@ static inline void *kmap_atomic(struct page *page, enum km_type idx)
 
 #endif /* CONFIG_HIGHMEM */
 
+/* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
+/* kunmap_atomic() should get the return value of kmap_atomic, not the page. */
+#define kunmap_atomic(addr, idx) do { \
+               BUILD_BUG_ON(__same_type((addr), struct page *)); \
+               kunmap_atomic_notypecheck((addr), (idx)); \
+       } while (0)
+
 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 #ifndef clear_user_highpage
 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)