aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:22 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:23 +1100
commit9b473de87209fa86eb421b23386693b461612f30 (patch)
tree7fe30a3f37347d5bb6f2ade2cc09133ae158ea3d /kernel
parent730b69d225259565c705f5f5a11cb1aba69568f1 (diff)
downloadlinux-linaro-9b473de87209fa86eb421b23386693b461612f30.tar.gz
param: Fix duplicate module prefixes
Instead of insisting each new module_param sysfs entry is unique, handle the case where it already exists (for builtin modules). The current code assumes that all identical prefixes are together in the section: true for normal uses, but not necessarily so if someone overrides MODULE_PARAM_PREFIX. More importantly, it's not true with the new "core_param()" code which uses "kernel" as a prefix. This simplifies the caller for the builtin case, at a slight loss of efficiency (we do the lookup every time to see if the directory exists). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/params.c261
1 files changed, 141 insertions, 120 deletions
diff --git a/kernel/params.c b/kernel/params.c
index aca07e1a050..f27c992a462 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -373,6 +373,8 @@ int param_get_string(char *buffer, struct kernel_param *kp)
}
/* sysfs output in /sys/modules/XYZ/parameters/ */
+#define to_module_attr(n) container_of(n, struct module_attribute, attr);
+#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
extern struct kernel_param __start___param[], __stop___param[];
@@ -384,6 +386,7 @@ struct param_attribute
struct module_param_attrs
{
+ unsigned int num;
struct attribute_group grp;
struct param_attribute attrs[0];
};
@@ -434,69 +437,84 @@ static ssize_t param_attr_store(struct module_attribute *mattr,
#ifdef CONFIG_SYSFS
/*
- * param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
- * @mk: struct module_kobject (contains parent kobject)
- * @kparam: array of struct kernel_param, the actual parameter definitions
- * @num_params: number of entries in array
- * @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
+ * add_sysfs_param - add a parameter to sysfs
+ * @mk: struct module_kobject
+ * @kparam: the actual parameter definition to add to sysfs
+ * @name: name of parameter
*
- * Create a kobject for a (per-module) group of parameters, and create files
- * in sysfs. A pointer to the param_kobject is returned on success,
- * NULL if there's no parameter to export, or other ERR_PTR(err).
+ * Create a kobject if for a (per-module) parameter if mp NULL, and
+ * create file in sysfs. Returns an error on out of memory. Always cleans up
+ * if there's an error.
*/
-static __modinit struct module_param_attrs *
-param_sysfs_setup(struct module_kobject *mk,
- struct kernel_param *kparam,
- unsigned int num_params,
- unsigned int name_skip)
+static __modinit int add_sysfs_param(struct module_kobject *mk,
+ struct kernel_param *kp,
+ const char *name)
{
- struct module_param_attrs *mp;
- unsigned int valid_attrs = 0;
- unsigned int i, size[2];
- struct param_attribute *pattr;
- struct attribute **gattr;
- int err;
-
- for (i=0; i<num_params; i++) {
- if (kparam[i].perm)
- valid_attrs++;
+ struct module_param_attrs *new;
+ struct attribute **attrs;
+ int err, num;
+
+ /* We don't bother calling this with invisible parameters. */
+ BUG_ON(!kp->perm);
+
+ if (!mk->mp) {
+ num = 0;
+ attrs = NULL;
+ } else {
+ num = mk->mp->num;
+ attrs = mk->mp->grp.attrs;
}
- if (!valid_attrs)
- return NULL;
-
- size[0] = ALIGN(sizeof(*mp) +
- valid_attrs * sizeof(mp->attrs[0]),
- sizeof(mp->grp.attrs[0]));
- size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);
-
- mp = kzalloc(size[0] + size[1], GFP_KERNEL);
- if (!mp)
- return ERR_PTR(-ENOMEM);
+ /* Enlarge. */
+ new = krealloc(mk->mp,
+ sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
+ GFP_KERNEL);
+ if (!new) {
+ kfree(mk->mp);
+ err = -ENOMEM;
+ goto fail;
+ }
+ attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
+ if (!attrs) {
+ err = -ENOMEM;
+ goto fail_free_new;
+ }
- mp->grp.name = "parameters";
- mp->grp.attrs = (void *)mp + size[0];
+ /* Sysfs wants everything zeroed. */
+ memset(new, 0, sizeof(*new));
+ memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
+ memset(&attrs[num], 0, sizeof(attrs[num]));
+ new->grp.name = "parameters";
+ new->grp.attrs = attrs;
+
+ /* Tack new one on the end. */
+ new->attrs[num].param = kp;
+ new->attrs[num].mattr.show = param_attr_show;
+ new->attrs[num].mattr.store = param_attr_store;
+ new->attrs[num].mattr.attr.name = (char *)name;
+ new->attrs[num].mattr.attr.mode = kp->perm;
+ new->num = num+1;
+
+ /* Fix up all the pointers, since krealloc can move us */
+ for (num = 0; num < new->num; num++)
+ new->grp.attrs[num] = &new->attrs[num].mattr.attr;
+ new->grp.attrs[num] = NULL;
+
+ mk->mp = new;
+ return 0;
- pattr = &mp->attrs[0];
- gattr = &mp->grp.attrs[0];
- for (i = 0; i < num_params; i++) {
- struct kernel_param *kp = &kparam[i];
- if (kp->perm) {
- pattr->param = kp;
- pattr->mattr.show = param_attr_show;
- pattr->mattr.store = param_attr_store;
- pattr->mattr.attr.name = (char *)&kp->name[name_skip];
- pattr->mattr.attr.mode = kp->perm;
- *(gattr++) = &(pattr++)->mattr.attr;
- }
- }
- *gattr = NULL;
+fail_free_new:
+ kfree(new);
+fail:
+ mk->mp = NULL;
+ return err;
+}
- if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
- kfree(mp);
- return ERR_PTR(err);
- }
- return mp;
+static void free_module_param_attrs(struct module_kobject *mk)
+{
+ kfree(mk->mp->grp.attrs);
+ kfree(mk->mp);
+ mk->mp = NULL;
}
#ifdef CONFIG_MODULES
@@ -506,21 +524,33 @@ param_sysfs_setup(struct module_kobject *mk,
* @kparam: module parameters (array)
* @num_params: number of module parameters
*
- * Adds sysfs entries for module parameters, and creates a link from
- * /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
+ * Adds sysfs entries for module parameters under
+ * /sys/module/[mod->name]/parameters/
*/
int module_param_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
- struct module_param_attrs *mp;
+ int i, err;
+ bool params = false;
+
+ for (i = 0; i < num_params; i++) {
+ if (kparam[i].perm == 0)
+ continue;
+ err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
+ if (err)
+ return err;
+ params = true;
+ }
- mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
- if (IS_ERR(mp))
- return PTR_ERR(mp);
+ if (!params)
+ return 0;
- mod->param_attrs = mp;
- return 0;
+ /* Create the param group. */
+ err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
+ if (err)
+ free_module_param_attrs(&mod->mkobj);
+ return err;
}
/*
@@ -532,43 +562,55 @@ int module_param_sysfs_setup(struct module *mod,
*/
void module_param_sysfs_remove(struct module *mod)
{
- if (mod->param_attrs) {
- sysfs_remove_group(&mod->mkobj.kobj,
- &mod->param_attrs->grp);
+ if (mod->mkobj.mp) {
+ sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
/* We are positive that no one is using any param
* attrs at this point. Deallocate immediately. */
- kfree(mod->param_attrs);
- mod->param_attrs = NULL;
+ free_module_param_attrs(&mod->mkobj);
}
}
#endif
-/*
- * kernel_param_sysfs_setup - wrapper for built-in params support
- */
-static void __init kernel_param_sysfs_setup(const char *name,
- struct kernel_param *kparam,
- unsigned int num_params,
- unsigned int name_skip)
+static void __init kernel_add_sysfs_param(const char *name,
+ struct kernel_param *kparam,
+ unsigned int name_skip)
{
struct module_kobject *mk;
- int ret;
+ struct kobject *kobj;
+ int err;
- mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
- BUG_ON(!mk);
-
- mk->mod = THIS_MODULE;
- mk->kobj.kset = module_kset;
- ret = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, "%s", name);
- if (ret) {
- kobject_put(&mk->kobj);
- printk(KERN_ERR "Module '%s' failed to be added to sysfs, "
- "error number %d\n", name, ret);
- printk(KERN_ERR "The system will be unstable now.\n");
- return;
+ kobj = kset_find_obj(module_kset, name);
+ if (kobj) {
+ /* We already have one. Remove params so we can add more. */
+ mk = to_module_kobject(kobj);
+ /* We need to remove it before adding parameters. */
+ sysfs_remove_group(&mk->kobj, &mk->mp->grp);
+ } else {
+ mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
+ BUG_ON(!mk);
+
+ mk->mod = THIS_MODULE;
+ mk->kobj.kset = module_kset;
+ err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
+ "%s", name);
+ if (err) {
+ kobject_put(&mk->kobj);
+ printk(KERN_ERR "Module '%s' failed add to sysfs, "
+ "error number %d\n", name, err);
+ printk(KERN_ERR "The system will be unstable now.\n");
+ return;
+ }
+ /* So that exit path is even. */
+ kobject_get(&mk->kobj);
}
- param_sysfs_setup(mk, kparam, num_params, name_skip);
+
+ /* These should not fail at boot. */
+ err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
+ BUG_ON(err);
+ err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
+ BUG_ON(err);
kobject_uevent(&mk->kobj, KOBJ_ADD);
+ kobject_put(&mk->kobj);
}
/*
@@ -579,18 +621,19 @@ static void __init kernel_param_sysfs_setup(const char *name,
* The "module" name (KBUILD_MODNAME) is stored before a dot, the
* "parameter" name is stored behind a dot in kernel_param->name. So,
* extract the "module" name for all built-in kernel_param-eters,
- * and for all who have the same, call kernel_param_sysfs_setup.
+ * and for all who have the same, call kernel_add_sysfs_param.
*/
static void __init param_sysfs_builtin(void)
{
- struct kernel_param *kp, *kp_begin = NULL;
- unsigned int i, name_len, count = 0;
- char modname[MODULE_NAME_LEN] = "";
+ struct kernel_param *kp;
+ unsigned int name_len;
+ char modname[MODULE_NAME_LEN];
- for (i=0; i < __stop___param - __start___param; i++) {
+ for (kp = __start___param; kp < __stop___param; kp++) {
char *dot;
- kp = &__start___param[i];
+ if (kp->perm == 0)
+ continue;
dot = strchr(kp->name, '.');
if (!dot) {
@@ -599,37 +642,15 @@ static void __init param_sysfs_builtin(void)
continue;
}
name_len = dot - kp->name;
-
- /* new kbuild_modname? */
- if (strlen(modname) != name_len
- || strncmp(modname, kp->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);
-
- strncpy(modname, kp->name, name_len);
- modname[name_len] = '\0';
- count = 0;
- kp_begin = kp;
- }
- count++;
+ strncpy(modname, kp->name, name_len);
+ modname[name_len] = '\0';
+ kernel_add_sysfs_param(modname, kp, name_len+1);
}
-
- /* last kernel_params need to be registered as well */
- if (count)
- kernel_param_sysfs_setup(modname, kp_begin, count,
- strlen(modname)+1);
}
/* module-related sysfs stuff */
-#define to_module_attr(n) container_of(n, struct module_attribute, attr);
-#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
-
static ssize_t module_attr_show(struct kobject *kobj,
struct attribute *attr,
char *buf)