[RFC][PATCH 3/4] mm: k{,um}map_atomic() vs in_atomic()

Peter Zijlstra
2006-10-19T10:17:25Z

[-- Attachment #1: kmap_atomic_generic.patch --]
[-- Type: text/plain, Size: 2361 bytes --]

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>
---
include/asm-mips/highmem.h | 10 ++++++++--
include/linux/highmem.h | 8 +++++---
2 files changed, 13 insertions(+), 5 deletions(-)

Index: linux-2.6/include/asm-mips/highmem.h
===================================================================
--- linux-2.6.orig/include/asm-mips/highmem.h
+++ linux-2.6/include/asm-mips/highmem.h
@@ -21,6 +21,7 @@

#include <linux/init.h>
#include <linux/interrupt.h>
+#include <linux/uaccess.h>
#include <asm/kmap_types.h>

/* undef for production */
@@ -70,11 +71,16 @@ static inline void *kmap(struct page *pa

static inline void *kmap_atomic(struct page *page, enum km_type type)
{
+ pagefault_disable();
return page_address(page);
}

-static inline void kunmap_atomic(void *kvaddr, enum km_type type) { }
-#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
+static inline void kunmap_atomic(void *kvaddr, enum km_type type)
+{
+ pagefault_enable();
+}
+
+#define kmap_atomic_pfn(pfn, idx) kmap_atomic(pfn_to_page(pfn), (idx))

#define kmap_atomic_to_page(ptr) virt_to_page(ptr)

Index: linux-2.6/include/linux/highmem.h
===================================================================
--- linux-2.6.orig/include/linux/highmem.h
+++ linux-2.6/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 @@ static inline void *kmap(struct page *pa

#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)