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>
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index bd10f9f..c6f1392 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -269,6 +269,8 @@
int (*write) (struct tomoyo_io_buffer *);
/* Exclusive lock for this structure. */
struct mutex io_sem;
+ /* Index returned by tomoyo_read_lock(). */
+ int reader_idx;
/* The position currently reading from. */
struct list_head *read_var1;
/* Extra variables for reading. */
@@ -446,16 +448,28 @@
* @cookie: the &struct list_head to use as a cookie.
* @head: the head for your list.
*
- * Same with list_for_each() except that this primitive uses @cookie
+ * Same with list_for_each_rcu() except that this primitive uses @cookie
* so that we can continue iteration.
* @cookie must be NULL when iteration starts, and @cookie will become
* NULL when iteration finishes.
*/
-#define list_for_each_cookie(pos, cookie, head) \
- for (({ if (!cookie) \
- cookie = head; }), \
- pos = (cookie)->next; \
- prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
- (cookie) = pos, pos = pos->next)
+#define list_for_each_cookie(pos, cookie, head) \
+ for (({ if (!cookie) \
+ cookie = head; }), \
+ pos = rcu_dereference((cookie)->next); \
+ prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
+ (cookie) = pos, pos = rcu_dereference(pos->next))
+
+extern struct srcu_struct tomoyo_ss;
+
+static inline int tomoyo_read_lock(void)
+{
+ return srcu_read_lock(&tomoyo_ss);
+}
+
+static inline void tomoyo_read_unlock(int idx)
+{
+ srcu_read_unlock(&tomoyo_ss, idx);
+}
#endif /* !defined(_SECURITY_TOMOYO_COMMON_H) */
