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SubjectRe: [patch 2/2] rtmutex: Detect changes in the pi lock chain


hehe, I can almost follow this code :-)

How about something like this on top?

---
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -260,6 +260,11 @@ static void rt_mutex_adjust_prio(struct
*/
int max_lock_depth = 1024;

+static inline struct rt_mutex *task_blocked_on(struct task_struct *p)
+{
+ return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+}
+
/*
* Adjust the priority chain. Also used for deadlock detection.
* Decreases task's usage by one - may thus free the task.
@@ -443,10 +448,7 @@ static int rt_mutex_adjust_prio_chain(st
* blocked itself. If yes we store a pointer to the lock for
* the lock chain change detection above.
*/
- if (task->pi_blocked_on)
- next_lock = task->pi_blocked_on->lock;
- else
- next_lock = NULL;
+ next_lock = task_blocked_on(task);

raw_spin_unlock_irqrestore(&task->pi_lock, flags);

@@ -569,7 +571,7 @@ static int task_blocks_on_rt_mutex(struc
{
struct task_struct *owner = rt_mutex_owner(lock);
struct rt_mutex_waiter *top_waiter = waiter;
- struct rt_mutex *next_lock = NULL;
+ struct rt_mutex *next_lock;
unsigned long flags;
int chain_walk, res;

@@ -614,8 +616,8 @@ static int task_blocks_on_rt_mutex(struc
} else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) {
chain_walk = 1;
}
- if (owner->pi_blocked_on)
- next_lock = owner->pi_blocked_on->lock;
+
+ next_lock = task_blocked_on(owner);

raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
if (!chain_walk)
@@ -705,8 +707,7 @@ static void remove_waiter(struct rt_mute
}
__rt_mutex_adjust_prio(owner);

- if (owner->pi_blocked_on)
- next_lock = owner->pi_blocked_on->lock;
+ next_lock = task_blocked_on(owner);

raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
}[unhandled content-type:application/pgp-signature]
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