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Subjectmodule: sysfs - add 'uevent' file to allow coldplug
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Date
From: Kay Sievers <kay.sievers@vrfy.org>
Subject: module: sysfs - add 'uevent' file to allow built-in coldplug

Userspace wants to manage module parameters with udev rules.
This currently only works for loaded modules, but not for
built-in ones.

To allow access to the built-in modules we need to
re-trigger all module load events that happened before any
userspace was running. We already do the same thing for all
devices, subsystems(buses) and drivers.

This adds the currently missing /sys/module/<name>/uevent files
to all module entries.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
---

include/linux/module.h | 24 +++++++++++++-----------
kernel/module.c | 31 ++++++++++++++++++++++++-------
kernel/params.c | 12 +++++++-----
3 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index d9ca2d5..ac6975c 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -48,10 +48,18 @@ struct modversion_info

struct module;

+struct module_kobject
+{
+ struct kobject kobj;
+ struct module *mod;
+ struct kobject *drivers_dir;
+ struct module_param_attrs *mp;
+};
+
struct module_attribute {
- struct attribute attr;
- ssize_t (*show)(struct module_attribute *, struct module *, char *);
- ssize_t (*store)(struct module_attribute *, struct module *,
+ struct attribute attr;
+ ssize_t (*show)(struct module_attribute *, struct module_kobject *, char *);
+ ssize_t (*store)(struct module_attribute *, struct module_kobject *,
const char *, size_t count);
void (*setup)(struct module *, const char *);
int (*test)(struct module *);
@@ -65,15 +73,9 @@ struct module_version_attribute {
} __attribute__ ((__aligned__(sizeof(void *))));

extern ssize_t __modver_version_show(struct module_attribute *,
- struct module *, char *);
+ struct module_kobject *, char *);

-struct module_kobject
-{
- struct kobject kobj;
- struct module *mod;
- struct kobject *drivers_dir;
- struct module_param_attrs *mp;
-};
+extern struct module_attribute module_uevent;

/* These are either module local, or the kernel's dummy ones. */
extern int init_module(void);
diff --git a/kernel/module.c b/kernel/module.c
index 795bdc7..2f0d562 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -545,9 +545,9 @@ static void setup_modinfo_##field(struct module *mod, const char *s) \
mod->field = kstrdup(s, GFP_KERNEL); \
} \
static ssize_t show_modinfo_##field(struct module_attribute *mattr, \
- struct module *mod, char *buffer) \
+ struct module_kobject *mk, char *buffer) \
{ \
- return sprintf(buffer, "%s\n", mod->field); \
+ return sprintf(buffer, "%s\n", mk->mod->field); \
} \
static int modinfo_##field##_exists(struct module *mod) \
{ \
@@ -902,9 +902,9 @@ void symbol_put_addr(void *addr)
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
- struct module *mod, char *buffer)
+ struct module_kobject *mk, char *buffer)
{
- return sprintf(buffer, "%u\n", module_refcount(mod));
+ return sprintf(buffer, "%u\n", module_refcount(mk->mod));
}

static struct module_attribute refcnt = {
@@ -952,11 +952,11 @@ static inline int module_unload_init(struct module *mod)
#endif /* CONFIG_MODULE_UNLOAD */

static ssize_t show_initstate(struct module_attribute *mattr,
- struct module *mod, char *buffer)
+ struct module_kobject *mk, char *buffer)
{
const char *state = "unknown";

- switch (mod->state) {
+ switch (mk->mod->state) {
case MODULE_STATE_LIVE:
state = "live";
break;
@@ -975,10 +975,27 @@ static struct module_attribute initstate = {
.show = show_initstate,
};

+static ssize_t store_uevent(struct module_attribute *mattr,
+ struct module_kobject *mk,
+ const char *buffer, size_t count)
+{
+ enum kobject_action action;
+
+ if (kobject_action_type(buffer, count, &action) == 0)
+ kobject_uevent(&mk->kobj, action);
+ return count;
+}
+
+struct module_attribute module_uevent = {
+ .attr = { .name = "uevent", .mode = 0200 },
+ .store = store_uevent,
+};
+
static struct module_attribute *modinfo_attrs[] = {
&modinfo_version,
&modinfo_srcversion,
&initstate,
+ &module_uevent,
#ifdef CONFIG_MODULE_UNLOAD
&refcnt,
#endif
@@ -1187,7 +1204,7 @@ struct module_sect_attrs
};

static ssize_t module_sect_show(struct module_attribute *mattr,
- struct module *mod, char *buf)
+ struct module_kobject *mk, char *buf)
{
struct module_sect_attr *sattr =
container_of(mattr, struct module_sect_attr, mattr);
diff --git a/kernel/params.c b/kernel/params.c
index ed72e13..d2f02ca 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -511,7 +511,7 @@ struct module_param_attrs
#define to_param_attr(n) container_of(n, struct param_attribute, mattr)

static ssize_t param_attr_show(struct module_attribute *mattr,
- struct module *mod, char *buf)
+ struct module_kobject *mk, char *buf)
{
int count;
struct param_attribute *attribute = to_param_attr(mattr);
@@ -531,7 +531,7 @@ static ssize_t param_attr_show(struct module_attribute *mattr,

/* sysfs always hands a nul-terminated string in buf. We rely on that. */
static ssize_t param_attr_store(struct module_attribute *mattr,
- struct module *owner,
+ struct module_kobject *km,
const char *buf, size_t len)
{
int err;
@@ -730,6 +730,8 @@ static struct module_kobject * __init locate_module_kobject(const char *name)
mk->kobj.kset = module_kset;
err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
"%s", name);
+ if (!err)
+ err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
if (err) {
kobject_put(&mk->kobj);
printk(KERN_ERR
@@ -807,7 +809,7 @@ static void __init param_sysfs_builtin(void)
}

ssize_t __modver_version_show(struct module_attribute *mattr,
- struct module *mod, char *buf)
+ struct module_kobject *mk, char *buf)
{
struct module_version_attribute *vattr =
container_of(mattr, struct module_version_attribute, mattr);
@@ -852,7 +854,7 @@ static ssize_t module_attr_show(struct kobject *kobj,
if (!attribute->show)
return -EIO;

- ret = attribute->show(attribute, mk->mod, buf);
+ ret = attribute->show(attribute, mk, buf);

return ret;
}
@@ -871,7 +873,7 @@ static ssize_t module_attr_store(struct kobject *kobj,
if (!attribute->store)
return -EIO;

- ret = attribute->store(attribute, mk->mod, buf, len);
+ ret = attribute->store(attribute, mk, buf, len);

return ret;
}



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