revert "rtc: recycle id when unloading a rtc driver"

[platform/adaptation/renesas_rcar/renesas_kernel.git] / security / device_cgroup.c

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 842c254..19ecc8d 100644 (file)
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -82,6 +82,8 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig)
 {
        struct dev_exception_item *ex, *tmp, *new;
 
+       lockdep_assert_held(&devcgroup_mutex);
+
        list_for_each_entry(ex, orig, list) {
                new = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
                if (!new)
@@ -107,6 +109,8 @@ static int dev_exception_add(struct dev_cgroup *dev_cgroup,
 {
        struct dev_exception_item *excopy, *walk;
 
+       lockdep_assert_held(&devcgroup_mutex);
+
        excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
        if (!excopy)
                return -ENOMEM;
@@ -137,6 +141,8 @@ static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
 {
        struct dev_exception_item *walk, *tmp;
 
+       lockdep_assert_held(&devcgroup_mutex);
+
        list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) {
                if (walk->type != ex->type)
                        continue;
@@ -163,16 +169,18 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
 {
        struct dev_exception_item *ex, *tmp;
 
+       lockdep_assert_held(&devcgroup_mutex);
+
        list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
-               list_del(&ex->list);
-               kfree(ex);
+               list_del_rcu(&ex->list);
+               kfree_rcu(ex, rcu);
        }
 }
 
 /*
  * called from kernel/cgroup.c with cgroup_lock() held.
  */
-static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup)
+static struct cgroup_subsys_state *devcgroup_css_alloc(struct cgroup *cgroup)
 {
        struct dev_cgroup *dev_cgroup, *parent_dev_cgroup;
        struct cgroup *parent_cgroup;
@@ -202,7 +210,7 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup)
        return &dev_cgroup->css;
 }
 
-static void devcgroup_destroy(struct cgroup *cgroup)
+static void devcgroup_css_free(struct cgroup *cgroup)
 {
        struct dev_cgroup *dev_cgroup;
 
@@ -298,7 +306,11 @@ static int may_access(struct dev_cgroup *dev_cgroup,
        struct dev_exception_item *ex;
        bool match = false;
 
-       list_for_each_entry(ex, &dev_cgroup->exceptions, list) {
+       rcu_lockdep_assert(rcu_read_lock_held() ||
+                          lockdep_is_held(&devcgroup_mutex),
+                          "device_cgroup::may_access() called without proper synchronization");
+
+       list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) {
                if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
                        continue;
                if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
@@ -352,6 +364,8 @@ static int parent_has_perm(struct dev_cgroup *childcg,
  */
 static inline int may_allow_all(struct dev_cgroup *parent)
 {
+       if (!parent)
+               return 1;
        return parent->behavior == DEVCG_DEFAULT_ALLOW;
 }
 
@@ -376,11 +390,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
        int count, rc;
        struct dev_exception_item ex;
        struct cgroup *p = devcgroup->css.cgroup;
-       struct dev_cgroup *parent = cgroup_to_devcgroup(p->parent);
+       struct dev_cgroup *parent = NULL;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
 
+       if (p->parent)
+               parent = cgroup_to_devcgroup(p->parent);
+
        memset(&ex, 0, sizeof(ex));
        b = buffer;
 
@@ -391,11 +408,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                        if (!may_allow_all(parent))
                                return -EPERM;
                        dev_exception_clean(devcgroup);
+                       devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
+                       if (!parent)
+                               break;
+
                        rc = dev_exceptions_copy(&devcgroup->exceptions,
                                                 &parent->exceptions);
                        if (rc)
                                return rc;
-                       devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
                        break;
                case DEVCG_DENY:
                        dev_exception_clean(devcgroup);
@@ -544,8 +564,8 @@ static struct cftype dev_cgroup_files[] = {
 struct cgroup_subsys devices_subsys = {
        .name = "devices",
        .can_attach = devcgroup_can_attach,
-       .create = devcgroup_create,
-       .destroy = devcgroup_destroy,
+       .css_alloc = devcgroup_css_alloc,
+       .css_free = devcgroup_css_free,
        .subsys_id = devices_subsys_id,
        .base_cftypes = dev_cgroup_files,