TOMOYO: Use RCU primitives for list operation

Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 37 insertions, 26 deletions

diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index fcf52accce2b..2fd190168b7e 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -217,6 +217,8 @@ static DECLARE_RWSEM(tomoyo_domain_initializer_list_lock);
  * @is_delete:  True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_domain_initializer_entry(const char *domainname,
                                                   const char *program,
@@ -246,7 +248,7 @@ static int tomoyo_update_domain_initializer_entry(const char *domainname,
         if (!saved_program)
                 return -ENOMEM;
         down_write(&tomoyo_domain_initializer_list_lock);
-        list_for_each_entry(ptr, &tomoyo_domain_initializer_list, list) {
+        list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
                 if (ptr->is_not != is_not ||
                     ptr->domainname != saved_domainname ||
                     ptr->program != saved_program)
@@ -266,7 +268,7 @@ static int tomoyo_update_domain_initializer_entry(const char *domainname,
         new_entry->program = saved_program;
         new_entry->is_not = is_not;
         new_entry->is_last_name = is_last_name;
-        list_add_tail(&new_entry->list, &tomoyo_domain_initializer_list);
+        list_add_tail_rcu(&new_entry->list, &tomoyo_domain_initializer_list);
         error = 0;
  out:
         up_write(&tomoyo_domain_initializer_list_lock);
@@ -279,13 +281,14 @@ static int tomoyo_update_domain_initializer_entry(const char *domainname,
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
 {
         struct list_head *pos;
         bool done = true;
 
-        down_read(&tomoyo_domain_initializer_list_lock);
         list_for_each_cookie(pos, head->read_var2,
                              &tomoyo_domain_initializer_list) {
                 const char *no;
@@ -308,7 +311,6 @@ bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
                 if (!done)
                         break;
         }
-        up_read(&tomoyo_domain_initializer_list_lock);
         return done;
 }
 
@@ -320,6 +322,8 @@ bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
                                            const bool is_delete)
@@ -345,6 +349,8 @@ int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
  *
  * Returns true if executing @program reinitializes domain transition,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
                                          domainname,
@@ -355,8 +361,7 @@ static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
         struct tomoyo_domain_initializer_entry *ptr;
         bool flag = false;
 
-        down_read(&tomoyo_domain_initializer_list_lock);
-        list_for_each_entry(ptr,  &tomoyo_domain_initializer_list, list) {
+        list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
                 if (ptr->is_deleted)
                         continue;
                 if (ptr->domainname) {
@@ -376,7 +381,6 @@ static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
                 }
                 flag = true;
         }
-        up_read(&tomoyo_domain_initializer_list_lock);
         return flag;
 }
 
@@ -430,6 +434,8 @@ static DECLARE_RWSEM(tomoyo_domain_keeper_list_lock);
  * @is_delete:  True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_domain_keeper_entry(const char *domainname,
                                              const char *program,
@@ -459,7 +465,7 @@ static int tomoyo_update_domain_keeper_entry(const char *domainname,
         if (!saved_domainname)
                 return -ENOMEM;
         down_write(&tomoyo_domain_keeper_list_lock);
-        list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
+        list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
                 if (ptr->is_not != is_not ||
                     ptr->domainname != saved_domainname ||
                     ptr->program != saved_program)
@@ -479,7 +485,7 @@ static int tomoyo_update_domain_keeper_entry(const char *domainname,
         new_entry->program = saved_program;
         new_entry->is_not = is_not;
         new_entry->is_last_name = is_last_name;
-        list_add_tail(&new_entry->list, &tomoyo_domain_keeper_list);
+        list_add_tail_rcu(&new_entry->list, &tomoyo_domain_keeper_list);
         error = 0;
  out:
         up_write(&tomoyo_domain_keeper_list_lock);
@@ -493,6 +499,7 @@ static int tomoyo_update_domain_keeper_entry(const char *domainname,
  * @is_not:    True if it is "no_keep_domain" entry.
  * @is_delete: True if it is a delete request.
  *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
                                       const bool is_delete)
@@ -513,13 +520,14 @@ int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 {
         struct list_head *pos;
         bool done = true;
 
-        down_read(&tomoyo_domain_keeper_list_lock);
         list_for_each_cookie(pos, head->read_var2,
                              &tomoyo_domain_keeper_list) {
                 struct tomoyo_domain_keeper_entry *ptr;
@@ -542,7 +550,6 @@ bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
                 if (!done)
                         break;
         }
-        up_read(&tomoyo_domain_keeper_list_lock);
         return done;
 }
 
@@ -555,6 +562,8 @@ bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
  *
  * Returns true if executing @program supresses domain transition,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
                                     const struct tomoyo_path_info *program,
@@ -563,8 +572,7 @@ static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
         struct tomoyo_domain_keeper_entry *ptr;
         bool flag = false;
 
-        down_read(&tomoyo_domain_keeper_list_lock);
-        list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
+        list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
                 if (ptr->is_deleted)
                         continue;
                 if (!ptr->is_last_name) {
@@ -582,7 +590,6 @@ static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
                 }
                 flag = true;
         }
-        up_read(&tomoyo_domain_keeper_list_lock);
         return flag;
 }
 
@@ -627,6 +634,8 @@ static DECLARE_RWSEM(tomoyo_alias_list_lock);
  * @is_delete:     True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_alias_entry(const char *original_name,
                                      const char *aliased_name,
@@ -646,7 +655,7 @@ static int tomoyo_update_alias_entry(const char *original_name,
         if (!saved_original_name || !saved_aliased_name)
                 return -ENOMEM;
         down_write(&tomoyo_alias_list_lock);
-        list_for_each_entry(ptr, &tomoyo_alias_list, list) {
+        list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
                 if (ptr->original_name != saved_original_name ||
                     ptr->aliased_name != saved_aliased_name)
                         continue;
@@ -663,7 +672,7 @@ static int tomoyo_update_alias_entry(const char *original_name,
                 goto out;
         new_entry->original_name = saved_original_name;
         new_entry->aliased_name = saved_aliased_name;
-        list_add_tail(&new_entry->list, &tomoyo_alias_list);
+        list_add_tail_rcu(&new_entry->list, &tomoyo_alias_list);
         error = 0;
  out:
         up_write(&tomoyo_alias_list_lock);
@@ -676,13 +685,14 @@ static int tomoyo_update_alias_entry(const char *original_name,
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 {
         struct list_head *pos;
         bool done = true;
 
-        down_read(&tomoyo_alias_list_lock);
         list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
                 struct tomoyo_alias_entry *ptr;
 
@@ -695,7 +705,6 @@ bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
                 if (!done)
                         break;
         }
-        up_read(&tomoyo_alias_list_lock);
         return done;
 }
 
@@ -706,6 +715,8 @@ bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 {
@@ -724,6 +735,8 @@ int tomoyo_write_alias_policy(char *data, const bool is_delete)
  * @profile:    Profile number to assign if the domain was newly created.
  *
  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
                                                             domainname,
@@ -742,7 +755,7 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
         if (!saved_domainname)
                 goto out;
         /* Can I reuse memory of deleted domain? */
-        list_for_each_entry(domain, &tomoyo_domain_list, list) {
+        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
                 struct task_struct *p;
                 struct tomoyo_acl_info *ptr;
                 bool flag;
@@ -760,7 +773,7 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
                 read_unlock(&tasklist_lock);
                 if (flag)
                         continue;
-                list_for_each_entry(ptr, &domain->acl_info_list, list) {
+                list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
                         ptr->type |= TOMOYO_ACL_DELETED;
                 }
                 tomoyo_set_domain_flag(domain, true, domain->flags);
@@ -776,7 +789,7 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
                 INIT_LIST_HEAD(&domain->acl_info_list);
                 domain->domainname = saved_domainname;
                 domain->profile = profile;
-                list_add_tail(&domain->list, &tomoyo_domain_list);
+                list_add_tail_rcu(&domain->list, &tomoyo_domain_list);
         }
  out:
         up_write(&tomoyo_domain_list_lock);
@@ -789,6 +802,8 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
  * @bprm: Pointer to "struct linux_binprm".
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 {
@@ -849,8 +864,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
         if (tomoyo_pathcmp(&r, &s)) {
                 struct tomoyo_alias_entry *ptr;
                 /* Is this program allowed to be called via symbolic links? */
-                down_read(&tomoyo_alias_list_lock);
-                list_for_each_entry(ptr, &tomoyo_alias_list, list) {
+                list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
                         if (ptr->is_deleted ||
                             tomoyo_pathcmp(&r, ptr->original_name) ||
                             tomoyo_pathcmp(&s, ptr->aliased_name))
@@ -861,7 +875,6 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
                         tomoyo_fill_path_info(&r);
                         break;
                 }
-                up_read(&tomoyo_alias_list_lock);
         }
 
         /* Check execute permission. */
@@ -892,9 +905,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
         }
         if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
                 goto done;
-        down_read(&tomoyo_domain_list_lock);
         domain = tomoyo_find_domain(new_domain_name);
-        up_read(&tomoyo_domain_list_lock);
         if (domain)
                 goto done;
         if (is_enforce)