Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 546970bc authored by Rusty Russell's avatar Rusty Russell
Browse files

param: add kerneldoc to moduleparam.h



Also reorders the macros with the most common ones at the top.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: default avatarTakashi Iwai <tiwai@suse.de>
Tested-by: default avatarPhil Carmody <ext-phil.2.carmody@nokia.com>
parent 907b29eb
Loading
Loading
Loading
Loading
+95 −26
Original line number Diff line number Diff line
@@ -71,6 +71,62 @@ struct kparam_array
	void *elem;
};

/**
 * module_param - typesafe helper for a module/cmdline parameter
 * @value: the variable to alter, and exposed parameter name.
 * @type: the type of the parameter
 * @perm: visibility in sysfs.
 *
 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
 * ".") the kernel commandline parameter.  Note that - is changed to _, so
 * the user can use "foo-bar=1" even for variable "foo_bar".
 *
 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
 * for world-readable, 0644 for root-writable, etc.  Note that if it
 * is writable, you may need to use kparam_block_sysfs_write() around
 * accesses (esp. charp, which can be kfreed when it changes).
 *
 * The @type is simply pasted to refer to a param_ops_##type and a
 * param_check_##type: for convenience many standard types are provided but
 * you can create your own by defining those variables.
 *
 * Standard types are:
 *	byte, short, ushort, int, uint, long, ulong
 *	charp: a character pointer
 *	bool: a bool, values 0/1, y/n, Y/N.
 *	invbool: the above, only sense-reversed (N = true).
 */
#define module_param(name, type, perm)				\
	module_param_named(name, name, type, perm)

/**
 * module_param_named - typesafe helper for a renamed module/cmdline parameter
 * @name: a valid C identifier which is the parameter name.
 * @value: the actual lvalue to alter.
 * @type: the type of the parameter
 * @perm: visibility in sysfs.
 *
 * Usually it's a good idea to have variable names and user-exposed names the
 * same, but that's harder if the variable must be non-static or is inside a
 * structure.  This allows exposure under a different name.
 */
#define module_param_named(name, value, type, perm)			   \
	param_check_##type(name, &(value));				   \
	module_param_cb(name, &param_ops_##type, &value, perm);		   \
	__MODULE_PARM_TYPE(name, #type)

/**
 * module_param_cb - general callback for a module/cmdline parameter
 * @name: a valid C identifier which is the parameter name.
 * @ops: the set & get operations for this parameter.
 * @perm: visibility in sysfs.
 *
 * The ops can have NULL set or get functions.
 */
#define module_param_cb(name, ops, arg, perm)				      \
	__module_param_call(MODULE_PARAM_PREFIX,			      \
			    name, ops, arg, __same_type(*(arg), bool), perm)

/* On alpha, ia64 and ppc64 relocations to global data cannot go into
   read-only sections (which is part of respective UNIX ABI on these
   platforms). So 'const' makes no sense and even causes compile failures
@@ -82,9 +138,7 @@ struct kparam_array
#endif

/* This is the fundamental function for registering boot/module
   parameters.  perm sets the visibility in sysfs: 000 means it's
   not there, read bits mean it's readable, write bits mean it's
   writable. */
   parameters. */
#define __module_param_call(prefix, name, ops, arg, isbool, perm)	\
	/* Default value instead of permissions? */			\
	static int __param_perm_check_##name __attribute__((unused)) =	\
@@ -113,23 +167,6 @@ __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
	return 0;
}

#define module_param_cb(name, ops, arg, perm)				      \
	__module_param_call(MODULE_PARAM_PREFIX,			      \
			    name, ops, arg, __same_type(*(arg), bool), perm)

/*
 * Helper functions: type is byte, short, ushort, int, uint, long,
 * ulong, charp, bool or invbool, or XXX if you define param_ops_XXX
 * and param_check_XXX.
 */
#define module_param_named(name, value, type, perm)			   \
	param_check_##type(name, &(value));				   \
	module_param_cb(name, &param_ops_##type, &value, perm);		   \
	__MODULE_PARM_TYPE(name, #type)

#define module_param(name, type, perm)				\
	module_param_named(name, name, type, perm)

/**
 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
 * @name: the name of the parameter
@@ -191,7 +228,7 @@ static inline void __kernel_param_unlock(void)
 * core_param - define a historical core kernel parameter.
 * @name: the name of the cmdline and sysfs parameter (often the same as var)
 * @var: the variable
 * @type: the type (for param_set_##type and param_get_##type)
 * @type: the type of the parameter
 * @perm: visibility in sysfs
 *
 * core_param is just like module_param(), but cannot be modular and
@@ -205,7 +242,16 @@ static inline void __kernel_param_unlock(void)
			    &var, __same_type(var, bool), perm)
#endif /* !MODULE */

/* Actually copy string: maxlen param is usually sizeof(string). */
/**
 * module_param_string - a char array parameter
 * @name: the name of the parameter
 * @string: the string variable
 * @len: the maximum length of the string, incl. terminator
 * @perm: visibility in sysfs.
 *
 * This actually copies the string when it's set (unlike type charp).
 * @len is usually just sizeof(string).
 */
#define module_param_string(name, string, len, perm)			\
	static const struct kparam_string __param_string_##name		\
		= { len, string };					\
@@ -294,7 +340,33 @@ extern int param_set_invbool(const char *val, const struct kernel_param *kp);
extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
#define param_check_invbool(name, p) __param_check(name, p, bool)

/* Comma-separated array: *nump is set to number they actually specified. */
/**
 * module_param_array - a parameter which is an array of some type
 * @name: the name of the array variable
 * @type: the type, as per module_param()
 * @nump: optional pointer filled in with the number written
 * @perm: visibility in sysfs
 *
 * Input and output are as comma-separated values.  Commas inside values
 * don't work properly (eg. an array of charp).
 *
 * ARRAY_SIZE(@name) is used to determine the number of elements in the
 * array, so the definition must be visible.
 */
#define module_param_array(name, type, nump, perm)		\
	module_param_array_named(name, name, type, nump, perm)

/**
 * module_param_array_named - renamed parameter which is an array of some type
 * @name: a valid C identifier which is the parameter name
 * @array: the name of the array variable
 * @type: the type, as per module_param()
 * @nump: optional pointer filled in with the number written
 * @perm: visibility in sysfs
 *
 * This exposes a different name than the actual variable name.  See
 * module_param_named() for why this might be necessary.
 */
#define module_param_array_named(name, array, type, nump, perm)		\
	static const struct kparam_array __param_arr_##name		\
	= { ARRAY_SIZE(array), nump, &param_ops_##type,			\
@@ -305,9 +377,6 @@ extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
			    __same_type(array[0], bool), perm);		\
	__MODULE_PARM_TYPE(name, "array of " #type)

#define module_param_array(name, type, nump, perm)		\
	module_param_array_named(name, name, type, nump, perm)

extern struct kernel_param_ops param_array_ops;

extern struct kernel_param_ops param_ops_string;