Wed May 11 03:17:22 2016 UTC ()

provide const versions of container_of macros.

discussed with riastradh@ by email


(rtr)

diff -r1.122 -r1.123 src/sys/lib/libkern/libkern.h

--- src/sys/lib/libkern/libkern.h 2016/05/02 19:18:29	1.122
+++ src/sys/lib/libkern/libkern.h 2016/05/11 03:17:22	1.123

 @@ -1,14 +1,14 @@
-/*	$NetBSD: libkern.h,v 1.122 2016/05/02 19:18:29 christos Exp $	*/
+/*	$NetBSD: libkern.h,v 1.123 2016/05/11 03:17:22 rtr Exp $	*/
 /*-
  * Copyright (c) 1992, 1993
  *	The Regents of the University of California.  All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
 @@ -327,35 +327,42 @@ tolower(int ch)
  *	struct bar b;
  *	struct foo *fp = b.b_foo;
+ *
  * Now we can get at b from fp by:
+ *
  *	struct bar *bp = container_of(fp, struct bar, b_foo);
+ *
  * The 0*sizeof((PTR) - ...) causes the compiler to warn if the type of
  * *fp does not match the type of struct bar::b_foo.
  * We skip the validation for coverity runs to avoid warnings.
  */
 #ifdef __COVERITY__
 #define __validate_container_of(PTR, TYPE, FIELD) 0
 #define __validate_const_container_of(PTR, TYPE, FIELD) 0
 #else
 #define __validate_container_of(PTR, TYPE, FIELD)			\
     (0 * sizeof((PTR) - &((TYPE *)(((char *)(PTR)) -			\
     offsetof(TYPE, FIELD)))->FIELD))
 #define __validate_const_container_of(PTR, TYPE, FIELD)			\
     (0 * sizeof((PTR) - &((const TYPE *)(((const char *)(PTR)) -	\
     offsetof(TYPE, FIELD)))->FIELD))
 #endif
 #define	container_of(PTR, TYPE, FIELD)					\
     ((TYPE *)(((char *)(PTR)) - offsetof(TYPE, FIELD))			\
 	+ __validate_container_of(PTR, TYPE, FIELD))
 #define	const_container_of(PTR, TYPE, FIELD)				\
     ((const TYPE *)(((const char *)(PTR)) - offsetof(TYPE, FIELD))	\
 	+ __validate_const_container_of(PTR, TYPE, FIELD))
 #define	MTPRNG_RLEN		624
 struct mtprng_state {
 	unsigned int mt_idx;
 	uint32_t mt_elem[MTPRNG_RLEN];
 	uint32_t mt_count;
 	uint32_t mt_sparse[3];
 };
 /* Prototypes for which GCC built-ins exist. */
 void	*memcpy(void *, const void *, size_t);
 int	 memcmp(const void *, const void *, size_t);
 void	*memset(void *, int, size_t);