Commit cf14f27f authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

macro: introduce COUNT_ARGS() macro 



move COUNT_ARGS() macro from apparmor to generic header and extend it
to count till twelve.

COUNT() was an alternative name for this logic, but it's used for
different purpose in many other places.

Similarly for CONCATENATE() macro.

Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 4fe43c2c

include/linux/kernel.h

+7 −0
Original line number Diff line number Diff line
@@ -919,6 +919,13 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 
#define swap(a, b) \

	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)



/* This counts to 12. Any more, it will return 13th argument. */

#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n

#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)



#define __CONCAT(a, b) a ## b

#define CONCATENATE(a, b) __CONCAT(a, b)



/**

 * container_of - cast a member of a structure out to the containing structure

 * @ptr:	the pointer to the member.

security/apparmor/include/path.h

+1 −6
Original line number Diff line number Diff line
@@ -43,15 +43,10 @@ struct aa_buffers { 


DECLARE_PER_CPU(struct aa_buffers, aa_buffers);



#define COUNT_ARGS(X...) COUNT_ARGS_HELPER(, ##X, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)

#define COUNT_ARGS_HELPER(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, X...) n

#define CONCAT(X, Y) X ## Y

#define CONCAT_AFTER(X, Y) CONCAT(X, Y)



#define ASSIGN(FN, X, N) ((X) = FN(N))

#define EVAL1(FN, X) ASSIGN(FN, X, 0) /*X = FN(0)*/

#define EVAL2(FN, X, Y...) do { ASSIGN(FN, X, 1);  EVAL1(FN, Y); } while (0)

#define EVAL(FN, X...) CONCAT_AFTER(EVAL, COUNT_ARGS(X))(FN, X)

#define EVAL(FN, X...) CONCATENATE(EVAL, COUNT_ARGS(X))(FN, X)



#define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)

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