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Commit a solution for the SYSINIT vs C_SYSINIT conundrum. The

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problem and solution is outlined in the comments, but basically
    we needed a way to allow the SYSINIT mechanism to handle const void *
    arguments and function pointers as well as non-const arguments and
    function pointers while still maintaining the compiler's ability to
    issue warnings if you try to use a bad combination.
This commit is contained in:
Matthew Dillon 1999-01-29 08:12:49 +00:00
parent 425c50cf51
commit 12cb7f73a6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=43385
1 changed files with 29 additions and 21 deletions
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50
sys/sys/kernel.h
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@ -39,7 +39,7 @@
* SUCH DAMAGE.
*
* @(#)kernel.h 8.3 (Berkeley) 1/21/94
* $Id: kernel.h,v 1.50 1999/01/28 00:57:54 dillon Exp $
* $Id: kernel.h,v 1.51 1999/01/28 17:30:51 dillon Exp $
*/
#ifndef _SYS_KERNEL_H_
@ -180,28 +180,33 @@ typedef enum sysinit_elem_type {
* want two which is why this code is if'd out, but we definitely want
* to discern SYSINIT's which take non-constant data pointers and
* SYSINIT's which take constant data pointers,
*
* The C_* macros take functions expecting const void * arguments
* while the non-C_* macros take functions expecting just void * arguments.
*
* With -Wcast-qual on, the compiler issues warnings:
* - if we pass non-const data or functions taking non-const data
* to a C_* macro.
*
* - if we pass const data to the normal macros
*
* However, no warning is issued if we pass a function taking const data
* through a normal non-const macro. This is ok because the function is
* saying it won't modify the data so we don't care whether the data is
* modifiable or not.
*/
typedef void (*sysinit_nfunc_t) __P((void *));
typedef void (*sysinit_cfunc_t) __P((const void *));
struct sysinit {
unsigned int subsystem; /* subsystem identifier*/
unsigned int order; /* init order within subsystem*/
void (*func) __P((void *)); /* function */
void *udata; /* multiplexer/argument */
si_elem_t type; /* sysinit_elem_type*/
};
#if 0
struct c_sysinit {
unsigned int subsystem; /* subsystem identifier*/
unsigned int order; /* init order within subsystem*/
void (*func) __P((const void *)); /* function */
sysinit_cfunc_t func; /* function */
const void *udata; /* multiplexer/argument */
si_elem_t type; /* sysinit_elem_type*/
};
#endif
/*
* Default: no special processing
*
@ -210,8 +215,11 @@ struct c_sysinit {
* At the moment it is no different from SYSINIT and thus
* still results in warnings.
*
* The casts are necessary to have the compiler produce the
* correct warnings when -Wcast-qual is used.
*
*/
#define SYSINIT(uniquifier, subsystem, order, func, ident) \
#define C_SYSINIT(uniquifier, subsystem, order, func, ident) \
static struct sysinit uniquifier ## _sys_init = { \
subsystem, \
order, \
@ -221,13 +229,13 @@ struct c_sysinit {
}; \
DATA_SET(sysinit_set,uniquifier ## _sys_init);
#define C_SYSINIT(uniquifier, subsystem, order, func, ident) \
SYSINIT(uniquifier, subsystem, order, func, ident)
#define SYSINIT(uniquifier, subsystem, order, func, ident) \
C_SYSINIT(uniquifier, subsystem, order, (sysinit_cfunc_t)(sysinit_nfunc_t)func, (void *)ident)
/*
* Called on module unload: no special processing
*/
#define SYSUNINIT(uniquifier, subsystem, order, func, ident) \
#define C_SYSUNINIT(uniquifier, subsystem, order, func, ident) \
static struct sysinit uniquifier ## _sys_uninit = { \
subsystem, \
order, \
@ -237,8 +245,8 @@ struct c_sysinit {
}; \
DATA_SET(sysuninit_set,uniquifier ## _sys_uninit)
#define C_SYSUNINIT(uniquifier, subsystem, order, func, ident) \
SYSUNINIT(uniquifier, subsystem, order, func, ident)
#define SYSUNINIT(uniquifier, subsystem, order, func, ident) \
C_SYSUNINIT(uniquifier, subsystem, order, (sysinit_cfunc_t)(sysinit_nfunc_t)func, (void *)ident)
/*
* Call 'fork()' before calling '(*func)(ident)';