Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Core kernel parameters and /sys/parameters? | Date | Thu, 31 Jul 2008 13:59:02 +1000 |
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Hi Greg,
Was looking at implementing "core_param" for things like "initcall_debug" (ie. params with no prefix), and wanted to put them in sysfs of course. I hacked in a new "kernel" dir, but /sys/module/kernel/parameters/ is a bit of an odd place for it to end up in.
I noticed this comment in params.c:
* /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
I like the idea of /sys/parameters/ much better (perhaps even with core parameters at the top level). Is this obsolete? Planned?
Thanks, Rusty.
diff -r e7ea7e2ee243 include/linux/moduleparam.h --- a/include/linux/moduleparam.h Thu Jul 31 11:06:10 2008 +1000 +++ b/include/linux/moduleparam.h Thu Jul 31 13:58:16 2008 +1000 @@ -99,6 +99,25 @@ 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 that 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) \ diff -r e7ea7e2ee243 kernel/params.c --- a/kernel/params.c Thu Jul 31 11:06:10 2008 +1000 +++ b/kernel/params.c Thu Jul 31 13:58:16 2008 +1000 @@ -584,12 +584,14 @@ static void __init param_sysfs_builtin(v static void __init param_sysfs_builtin(void) { struct kernel_param *kp, *kp_begin = NULL; - unsigned int i, name_len, count = 0; + unsigned int i, name_len, skip, count = 0; char modname[MODULE_NAME_LEN + 1] = ""; + char core[] = "kernel"; for (i=0; i < __stop___param - __start___param; i++) { char *dot; size_t max_name_len; + const char *name; kp = &__start___param[i]; max_name_len = @@ -597,25 +599,28 @@ static void __init param_sysfs_builtin(v dot = memchr(kp->name, '.', max_name_len); if (!dot) { - DEBUGP("couldn't find period in first %d characters " - "of %s\n", MODULE_NAME_LEN, kp->name); - continue; + name = core; + name_len = strlen(name); + } else { + name = kp->name; + name_len = dot - kp->name; } - name_len = dot - kp->name; /* new kbuild_modname? */ if (strlen(modname) != name_len - || strncmp(modname, kp->name, name_len) != 0) { + || strncmp(modname, name, name_len) != 0) { /* add a new kobject for previous kernel_params. */ if (count) - kernel_param_sysfs_setup(modname, - kp_begin, - count, - strlen(modname)+1); + kernel_param_sysfs_setup(modname, kp_begin, + count, skip); - strncpy(modname, kp->name, name_len); + strncpy(modname, name, name_len); modname[name_len] = '\0'; count = 0; + if (!dot) + skip = 0; + else + skip = name_len + 1; kp_begin = kp; } count++; @@ -623,8 +628,7 @@ static void __init param_sysfs_builtin(v /* last kernel_params need to be registered as well */ if (count) - kernel_param_sysfs_setup(modname, kp_begin, count, - strlen(modname)+1); + kernel_param_sysfs_setup(modname, kp_begin, count, skip); }
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