[PATCH] mm: k{,um}map_atomic() vs in_atomic()
Make kmap_atomic/kunmap_atomic denote a pagefault disabled scope. All non
trivial implementations already do this anyway.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index fd7d12d..3d8768b 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -3,6 +3,7 @@
#include <linux/fs.h>
#include <linux/mm.h>
+#include <linux/uaccess.h>
#include <asm/cacheflush.h>
@@ -41,9 +42,10 @@
#define kunmap(page) do { (void) (page); } while (0)
-#define kmap_atomic(page, idx) page_address(page)
-#define kunmap_atomic(addr, idx) do { } while (0)
-#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
+#define kmap_atomic(page, idx) \
+ ({ pagefault_disable(); page_address(page); })
+#define kunmap_atomic(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)
#endif