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From: Juri Lelli <juri.lelli@gmail.com>
To: mingo@kernel.org, williams@redhat.com
Cc: linux-kernel@vger.kernel.org, Juri Lelli <juri.lelli@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH] rtmutex: document rt_mutex_adjust_prio_chain()
Date: Wed, 15 May 2013 11:04:10 +0200	[thread overview]
Message-ID: <1368608650-7935-1-git-send-email-juri.lelli@gmail.com> (raw)

Parameters and usage of rt_mutex_adjust_prio_chain() are already
documented in Documentation/rt-mutex-design.txt. However, since this
function is called from several paths with different semantics (related
to the arguments), it is handy to have a quick reference directly in
the code.

Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 kernel/rtmutex.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 1e09308..0dd6aec 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -145,6 +145,19 @@ int max_lock_depth = 1024;
 /*
  * Adjust the priority chain. Also used for deadlock detection.
  * Decreases task's usage by one - may thus free the task.
+ *
+ * @task: the task owning the mutex (owner) for which a chain walk is probably
+ *	  needed
+ * @deadlock_detect: do we have to carry out deadlock detection?
+ * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck
+ * 	       things for a task that has just got its priority adjusted, and
+ *	       is waiting on a mutex)
+ * @orig_waiter: rt_mutex_waiter struct for the task that has just donated
+ *		 its priority to the mutex owner (can be NULL in the case
+ *		 depicted above or if the top waiter is gone away and we are
+ *		 actually deboosting the owner)
+ * @top_task: the current top waiter
+ *
  * Returns 0 or -EDEADLK.
  */
 static int rt_mutex_adjust_prio_chain(struct task_struct *task,
-- 
1.7.9.5


             reply	other threads:[~2013-05-15  9:05 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-15  9:04 Juri Lelli [this message]
2013-05-28 13:04 ` [tip:core/locking] rtmutex: Document rt_mutex_adjust_prio_chain() tip-bot for Juri Lelli

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