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authorRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:23 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:23 +1100
commit67e67ceaac5bf55dbdceb704ff2d763d438b5373 (patch)
tree59523536661c93dce7a02557ca6ac5827a7bf75f
parent9b473de87209fa86eb421b23386693b461612f30 (diff)
core_param() for genuinely core kernel parameters
There are a lot of one-liner uses of __setup() in the kernel: they're cumbersome and not queryable (definitely not settable) via /sys. Yet it's ugly to simplify them to module_param(), because by default that inserts a prefix of the module name (usually filename). So, introduce a "core_param". The parameter gets no prefix, but appears in /sys/module/kernel/parameters/ (if non-zero perms arg). I thought about using the name "core", but that's more common than "kernel". And if you create a module called "kernel", you will die a horrible death. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--include/linux/moduleparam.h19
-rw-r--r--kernel/params.c14
2 files changed, 26 insertions, 7 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 1eefe6d61b8..e4af3399ef4 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -104,6 +104,25 @@ struct kparam_array
#define module_param(name, type, perm) \
module_param_named(name, name, type, perm)
+#ifndef MODULE
+/**
+ * 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)
+ * @perm: visibility in sysfs
+ *
+ * core_param is just like module_param(), but cannot be modular and
+ * doesn't add a prefix (such as "printk."). This is for compatibility
+ * with __setup(), and it makes sense as truly core parameters aren't
+ * tied to the particular file they're in.
+ */
+#define core_param(name, var, type, perm) \
+ param_check_##type(name, &(var)); \
+ __module_param_call("", name, param_set_##type, param_get_##type, \
+ &var, perm)
+#endif /* !MODULE */
+
/* Actually copy string: maxlen param is usually sizeof(string). */
#define module_param_string(name, string, len, perm) \
static const struct kparam_string __param_string_##name \
diff --git a/kernel/params.c b/kernel/params.c
index f27c992a462..b077f1b045d 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -637,14 +637,14 @@ static void __init param_sysfs_builtin(void)
dot = strchr(kp->name, '.');
if (!dot) {
- DEBUGP("couldn't find period in first %d characters "
- "of %s\n", MODULE_NAME_LEN, kp->name);
- continue;
+ /* This happens for core_param() */
+ strcpy(modname, "kernel");
+ name_len = 0;
+ } else {
+ name_len = dot - kp->name + 1;
+ strlcpy(modname, kp->name, name_len);
}
- name_len = dot - kp->name;
- strncpy(modname, kp->name, name_len);
- modname[name_len] = '\0';
- kernel_add_sysfs_param(modname, kp, name_len+1);
+ kernel_add_sysfs_param(modname, kp, name_len);
}
}