From 5c809064a94ddb6b10f9d10b1eb0498c9c02470d Mon Sep 17 00:00:00 2001
From: Wolfram Sang <w.sang@pengutronix.de>
Date: Tue, 4 May 2010 11:09:27 +0200
Subject: [PATCH] --- yaml --- r: 190541 b: refs/heads/master c:
 e4a7b9b04de15f6b63da5ccdd373ffa3057a3681 h: refs/heads/master i:   190539:
 818f51c2362dccb4fd290cd7a3c79906fb3680c4 v: v3

---
 [refs]                                  |  2 +-
 trunk/Documentation/i2c/writing-clients |  5 +++++
 trunk/drivers/i2c/i2c-core.c            |  8 ++++++--
 trunk/kernel/cgroup_freezer.c           |  5 +----
 trunk/kernel/perf_event.c               |  2 +-
 trunk/kernel/sched.c                    | 18 ++++--------------
 6 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/[refs] b/[refs]
index ba24cf1cda73..b52a18d93326 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f5fa05d97252b23b12749a7cd02710870c0762b0
+refs/heads/master: e4a7b9b04de15f6b63da5ccdd373ffa3057a3681
diff --git a/trunk/Documentation/i2c/writing-clients b/trunk/Documentation/i2c/writing-clients
index 3219ee0dbfef..5ebf5af1d716 100644
--- a/trunk/Documentation/i2c/writing-clients
+++ b/trunk/Documentation/i2c/writing-clients
@@ -74,6 +74,11 @@ structure at all.  You should use this to keep device-specific data.
 	/* retrieve the value */
 	void *i2c_get_clientdata(const struct i2c_client *client);
 
+Note that starting with kernel 2.6.34, you don't have to set the `data' field
+to NULL in remove() or if probe() failed anymore. The i2c-core does this
+automatically on these occasions. Those are also the only times the core will
+touch this field.
+
 
 Accessing the client
 ====================
diff --git a/trunk/drivers/i2c/i2c-core.c b/trunk/drivers/i2c/i2c-core.c
index 3202a86f420e..b9306b1a6baa 100644
--- a/trunk/drivers/i2c/i2c-core.c
+++ b/trunk/drivers/i2c/i2c-core.c
@@ -117,8 +117,10 @@ static int i2c_device_probe(struct device *dev)
 	dev_dbg(dev, "probe\n");
 
 	status = driver->probe(client, i2c_match_id(driver->id_table, client));
-	if (status)
+	if (status) {
 		client->driver = NULL;
+		i2c_set_clientdata(client, NULL);
+	}
 	return status;
 }
 
@@ -139,8 +141,10 @@ static int i2c_device_remove(struct device *dev)
 		dev->driver = NULL;
 		status = 0;
 	}
-	if (status == 0)
+	if (status == 0) {
 		client->driver = NULL;
+		i2c_set_clientdata(client, NULL);
+	}
 	return status;
 }
 
diff --git a/trunk/kernel/cgroup_freezer.c b/trunk/kernel/cgroup_freezer.c
index e5c0244962b0..da5e13975531 100644
--- a/trunk/kernel/cgroup_freezer.c
+++ b/trunk/kernel/cgroup_freezer.c
@@ -205,12 +205,9 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 	 * No lock is needed, since the task isn't on tasklist yet,
 	 * so it can't be moved to another cgroup, which means the
 	 * freezer won't be removed and will be valid during this
-	 * function call.  Nevertheless, apply RCU read-side critical
-	 * section to suppress RCU lockdep false positives.
+	 * function call.
 	 */
-	rcu_read_lock();
 	freezer = task_freezer(task);
-	rcu_read_unlock();
 
 	/*
 	 * The root cgroup is non-freezable, so we can skip the
diff --git a/trunk/kernel/perf_event.c b/trunk/kernel/perf_event.c
index 3d1552d3c12b..2f3fbf84215a 100644
--- a/trunk/kernel/perf_event.c
+++ b/trunk/kernel/perf_event.c
@@ -4897,7 +4897,7 @@ SYSCALL_DEFINE5(perf_event_open,
 
 err_free_put_context:
 	if (err < 0)
-		free_event(event);
+		kfree(event);
 
 err_put_context:
 	if (err < 0)
diff --git a/trunk/kernel/sched.c b/trunk/kernel/sched.c
index 3c2a54f70ffe..6af210a7de70 100644
--- a/trunk/kernel/sched.c
+++ b/trunk/kernel/sched.c
@@ -323,15 +323,6 @@ static inline struct task_group *task_group(struct task_struct *p)
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
 {
-	/*
-	 * Strictly speaking this rcu_read_lock() is not needed since the
-	 * task_group is tied to the cgroup, which in turn can never go away
-	 * as long as there are tasks attached to it.
-	 *
-	 * However since task_group() uses task_subsys_state() which is an
-	 * rcu_dereference() user, this quiets CONFIG_PROVE_RCU.
-	 */
-	rcu_read_lock();
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
 	p->se.parent = task_group(p)->se[cpu];
@@ -341,7 +332,6 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
 	p->rt.rt_rq  = task_group(p)->rt_rq[cpu];
 	p->rt.parent = task_group(p)->rt_se[cpu];
 #endif
-	rcu_read_unlock();
 }
 
 #else
@@ -3790,7 +3780,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
 	 * the mutex owner just released it and exited.
 	 */
 	if (probe_kernel_address(&owner->cpu, cpu))
-		return 0;
+		goto out;
 #else
 	cpu = owner->cpu;
 #endif
@@ -3800,14 +3790,14 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
 	 * the cpu field may no longer be valid.
 	 */
 	if (cpu >= nr_cpumask_bits)
-		return 0;
+		goto out;
 
 	/*
 	 * We need to validate that we can do a
 	 * get_cpu() and that we have the percpu area.
 	 */
 	if (!cpu_online(cpu))
-		return 0;
+		goto out;
 
 	rq = cpu_rq(cpu);
 
@@ -3826,7 +3816,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
 
 		cpu_relax();
 	}
-
+out:
 	return 1;
 }
 #endif