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Commit 980c19e3 authored by Cong Wang's avatar Cong Wang Committed by Cong Wang
Browse files

highmem: mark k[un]map_atomic() with two arguments as deprecated 



For backward compatibility, we still keep the deprecated form,
and will warn the users if they still use the deprecated one, like this:

drivers/block/drbd/drbd_bitmap.c: In function ‘bm_page_io_async’:
drivers/block/drbd/drbd_bitmap.c:973:3: warning: ‘kmap_atomic_deprecated’ is deprecated (declared at /home/wangcong/linux-2.6/include/linux/highmem.h:124)
drivers/block/drbd/drbd_bitmap.c:977:3: warning: ‘kunmap_atomic_deprecated’ is deprecated (declared at /home/wangcong/linux-2.6/include/linux/highmem.h:144)

Thanks to Nick Bowler for the cpp trick!

Cc: Cesar Eduardo Barros <cesarb@cesarb.net>
Cc: Nick Bowler <nbowler@elliptictech.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarCong Wang <amwang@redhat.com>
parent c16fa4f2

include/linux/highmem.h

+46 −6
Original line number Diff line number Diff line
@@ -109,20 +109,60 @@ static inline void kmap_atomic_idx_pop(void) 
#endif



/*

 * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.

 * NOTE:

 * kmap_atomic() and kunmap_atomic() with two arguments are deprecated.

 * We only keep them for backward compatibility, any usage of them

 * are now warned.

 */

#define kmap_atomic(page, args...) __kmap_atomic(page)



#define PASTE(a, b) a ## b

#define PASTE2(a, b) PASTE(a, b)



#define NARG_(_2, _1, n, ...) n

#define NARG(...) NARG_(__VA_ARGS__, 2, 1, :)



static inline void *kmap_atomic(struct page *page)

{

	return __kmap_atomic(page);

}



static inline void __deprecated *kmap_atomic_deprecated(struct page *page,

							enum km_type km)

{

	return __kmap_atomic(page);

}



#define kmap_atomic1(...) kmap_atomic(__VA_ARGS__)

#define kmap_atomic2(...) kmap_atomic_deprecated(__VA_ARGS__)

#define kmap_atomic(...) PASTE2(kmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))



static inline void __deprecated __kunmap_atomic_deprecated(void *addr,

							enum km_type km)

{

	__kunmap_atomic(addr);

}



/*

 * 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, args...)				\

#define kunmap_atomic_deprecated(addr, km)                      \

do {                                                            \

	BUILD_BUG_ON(__same_type((addr), struct page *));       \

	__kunmap_atomic_deprecated(addr, km);                   \

} while (0)



#define kunmap_atomic_withcheck(addr)                           \

do {                                                            \

	BUILD_BUG_ON(__same_type((addr), struct page *));       \

	__kunmap_atomic(addr);                                  \

} while (0)



#define kunmap_atomic1(...) kunmap_atomic_withcheck(__VA_ARGS__)

#define kunmap_atomic2(...) kunmap_atomic_deprecated(__VA_ARGS__)

#define kunmap_atomic(...) PASTE2(kunmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))

/**** End of C pre-processor tricks for deprecated macros ****/



/* 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)