[PATCH v3 04/13] futex: Consolidate pure pi_state_list add & delete codes to helpers

[Waiman Long]

Two new helper functions (task_pi_list_add & task_pi_list_del)
are created to consolidate all the pure pi_state_list addition and
insertion codes. The set_owner argument in task_pi_list_add() will
be needed in a later patch.

Signed-off-by: Waiman Long <waiman.l...@hpe.com>
---
 kernel/futex.c |   67 +++++++++++++++++++++++++++++++++++---------------------
 1 files changed, 42 insertions(+), 25 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index ebe59fa..0d1b1be 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -813,6 +813,42 @@ static inline int get_futex_value(u32 *dest, u32 __user 
*from)
 /*
  * PI code:
  */
+
+/**
+ * task_pi_list_add - add futex state object to a task's pi_state_list
+ * @task :     task structure
+ * @state:     futex state object
+ * @set_owner: set futex state owner to the given task if true
+ */
+static inline void task_pi_list_add(struct task_struct *task,
+                                   struct futex_state *state,
+                                   const bool set_owner)
+{
+       raw_spin_lock_irq(&task->pi_lock);
+       WARN_ON(!list_empty(&state->list));
+       list_add(&state->list, &task->pi_state_list);
+       if (set_owner)
+               state->owner = task;
+       raw_spin_unlock_irq(&task->pi_lock);
+}
+
+/**
+ * task_pi_list_del - delete futex state object from a task's pi_state_list
+ * @task : task structure
+ * @state: futex state object
+ * @warn : warn if list is empty when set
+ */
+static inline void task_pi_list_del(struct task_struct *task,
+                                   struct futex_state *state,
+                                   const bool warn)
+{
+       raw_spin_lock_irq(&task->pi_lock);
+       if (warn)
+               WARN_ON(list_empty(&state->list));
+       list_del_init(&state->list);
+       raw_spin_unlock_irq(&task->pi_lock);
+}
+
 static int refill_futex_state_cache(void)
 {
        struct futex_state *state;
@@ -865,9 +901,7 @@ static void put_futex_state(struct futex_state *state)
         * and has cleaned up the futex state already
         */
        if (state->owner) {
-               raw_spin_lock_irq(&state->owner->pi_lock);
-               list_del_init(&state->list);
-               raw_spin_unlock_irq(&state->owner->pi_lock);
+               task_pi_list_del(state->owner, state, false);
 
                rt_mutex_proxy_unlock(&state->pi_mutex, state->owner);
        }
@@ -1388,16 +1422,8 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, 
struct futex_q *this,
                return ret;
        }
 
-       raw_spin_lock(&pi_state->owner->pi_lock);
-       WARN_ON(list_empty(&pi_state->list));
-       list_del_init(&pi_state->list);
-       raw_spin_unlock(&pi_state->owner->pi_lock);
-
-       raw_spin_lock(&new_owner->pi_lock);
-       WARN_ON(!list_empty(&pi_state->list));
-       list_add(&pi_state->list, &new_owner->pi_state_list);
-       pi_state->owner = new_owner;
-       raw_spin_unlock(&new_owner->pi_lock);
+       task_pi_list_del(pi_state->owner, pi_state, true);
+       task_pi_list_add(new_owner, pi_state, true);
 
        raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 
@@ -2202,19 +2228,10 @@ retry:
         * We fixed up user space. Now we need to fix the pi_state
         * itself.
         */
-       if (pi_state->owner != NULL) {
-               raw_spin_lock_irq(&pi_state->owner->pi_lock);
-               WARN_ON(list_empty(&pi_state->list));
-               list_del_init(&pi_state->list);
-               raw_spin_unlock_irq(&pi_state->owner->pi_lock);
-       }
+       if (pi_state->owner != NULL)
+               task_pi_list_del(pi_state->owner, pi_state, true);
 
-       pi_state->owner = newowner;
-
-       raw_spin_lock_irq(&newowner->pi_lock);
-       WARN_ON(!list_empty(&pi_state->list));
-       list_add(&pi_state->list, &newowner->pi_state_list);
-       raw_spin_unlock_irq(&newowner->pi_lock);
+       task_pi_list_add(newowner, pi_state, true);
        return 0;
 
        /*
-- 
1.7.1