82 lines
2.5 KiB
Diff
82 lines
2.5 KiB
Diff
|
From 39f710e222c6e981f751df63b84ecb82b67940d0 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Peter Zijlstra <peterz@infradead.org>
|
||
|
|
Date: Wed, 22 Mar 2017 11:35:53 +0100
|
||
|
|
Subject: [PATCH 010/365] futex: Cleanup refcounting
|
||
|
|
|
||
|
|
Upstream commit bf92cf3a5100f5a0d5f9834787b130159397cb22
|
||
|
|
|
||
|
|
Add a put_pit_state() as counterpart for get_pi_state() so the refcounting
|
||
|
|
becomes consistent.
|
||
|
|
|
||
|
|
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
|
||
|
|
Cc: juri.lelli@arm.com
|
||
|
|
Cc: bigeasy@linutronix.de
|
||
|
|
Cc: xlpang@redhat.com
|
||
|
|
Cc: rostedt@goodmis.org
|
||
|
|
Cc: mathieu.desnoyers@efficios.com
|
||
|
|
Cc: jdesfossez@efficios.com
|
||
|
|
Cc: dvhart@infradead.org
|
||
|
|
Cc: bristot@redhat.com
|
||
|
|
Link: http://lkml.kernel.org/r/20170322104151.801778516@infradead.org
|
||
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
||
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
||
|
|
---
|
||
|
|
kernel/futex.c | 13 +++++++++----
|
||
|
|
1 file changed, 9 insertions(+), 4 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/kernel/futex.c b/kernel/futex.c
|
||
|
|
index c0d5e64b37b2..629db2cd530e 100644
|
||
|
|
--- a/kernel/futex.c
|
||
|
|
+++ b/kernel/futex.c
|
||
|
|
@@ -818,7 +818,7 @@ static int refill_pi_state_cache(void)
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
-static struct futex_pi_state * alloc_pi_state(void)
|
||
|
|
+static struct futex_pi_state *alloc_pi_state(void)
|
||
|
|
{
|
||
|
|
struct futex_pi_state *pi_state = current->pi_state_cache;
|
||
|
|
|
||
|
|
@@ -828,6 +828,11 @@ static struct futex_pi_state * alloc_pi_state(void)
|
||
|
|
return pi_state;
|
||
|
|
}
|
||
|
|
|
||
|
|
+static void get_pi_state(struct futex_pi_state *pi_state)
|
||
|
|
+{
|
||
|
|
+ WARN_ON_ONCE(!atomic_inc_not_zero(&pi_state->refcount));
|
||
|
|
+}
|
||
|
|
+
|
||
|
|
/*
|
||
|
|
* Drops a reference to the pi_state object and frees or caches it
|
||
|
|
* when the last reference is gone.
|
||
|
|
@@ -872,7 +877,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
|
||
|
|
* Look up the task based on what TID userspace gave us.
|
||
|
|
* We dont trust it.
|
||
|
|
*/
|
||
|
|
-static struct task_struct * futex_find_get_task(pid_t pid)
|
||
|
|
+static struct task_struct *futex_find_get_task(pid_t pid)
|
||
|
|
{
|
||
|
|
struct task_struct *p;
|
||
|
|
|
||
|
|
@@ -1119,7 +1124,7 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
|
||
|
|
goto out_einval;
|
||
|
|
|
||
|
|
out_attach:
|
||
|
|
- atomic_inc(&pi_state->refcount);
|
||
|
|
+ get_pi_state(pi_state);
|
||
|
|
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
||
|
|
*ps = pi_state;
|
||
|
|
return 0;
|
||
|
|
@@ -2056,7 +2061,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
|
||
|
|
* refcount on the pi_state and store the pointer in
|
||
|
|
* the futex_q object of the waiter.
|
||
|
|
*/
|
||
|
|
- atomic_inc(&pi_state->refcount);
|
||
|
|
+ get_pi_state(pi_state);
|
||
|
|
this->pi_state = pi_state;
|
||
|
|
ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex,
|
||
|
|
this->rt_waiter,
|
||
|
|
--
|
||
|
|
2.28.0
|
||
|
|
|