[ANNOUNCE] 3.14.3-rt5

From: Sebastian Andrzej Siewior
Date: Fri May 09 2014 - 14:12:21 EST

Dear RT folks!

I'm pleased to announce the v3.14.3-rt5 patch set.

Changes since v3.14.3-rt4
- remove one of the two identical rt_mutex_init() definitions. A patch
from Steven Rostedt
- use EXPORT_SYMBOL() on __rt_mutex_init() and
rt_down_write_nested_lock(). The former was dropped accidently and is
needed by some binary only modules, the latter was requsted by the f2fs
module. Patch by Joakim Hernberg.
- during v3.14 porting I accidently dropped preempt_check_resched() in
the non-preempt case which means configs non-preempt configs did not
build. Reported by Yang Honggang.
- NETCONSOLE is no longer disabled on RT. Daniel Bristot de Oliveira did
some testing and did not find anything wrong it. That means it can be
enabled if someone needs/wants it.
- rt_read_lock() uses rwlock_acquire() instead of rwlock_acquire_read()
for lockdep annotation. It was different compared to what the trylock
variant used and on RT both act the same way. Patch by Mike Galbraith.
- the tracing code wrongly disable preemption while shrinking the ring
buffer. Reported by Stanislav Meduna.

Known issues:

- bcache is disabled.

- lazy preempt on x86_64 leads to a crash with some load.

- CPU hotplug works in general. Steven's test script however
deadlocks usually on the second invocation.

The delta patch against v3.14.3-rt4 is appended below and can be found
here:
https://www.kernel.org/pub/linux/kernel/projects/rt/3.14/incr/patch-3.14.3-rt4-rt5.patch.xz

The RT patch against 3.14.3 can be found here:

https://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patch-3.14.3-rt5.patch.xz

The split quilt queue is available at:

https://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patches-3.14.3-rt5.tar.xz

Sebastian

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 33a4a85..494b888 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -160,7 +160,6 @@ config VXLAN

config NETCONSOLE
tristate "Network console logging support"
- depends on !PREEMPT_RT_FULL
---help---
If you want to log kernel messages over the network, enable this.
See <file:Documentation/networking/netconsole.txt> for details.
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 5b2cdf4..66587bf 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -149,6 +149,7 @@ do { \
#define sched_preempt_enable_no_resched() barrier()
#define preempt_enable_no_resched() barrier()
#define preempt_enable() barrier()
+#define preempt_check_resched() do { } while (0)

#define preempt_disable_notrace() barrier()
#define preempt_enable_no_resched_notrace() barrier()
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index f8f3dfdd2..edb77fd 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -59,23 +59,18 @@ struct hrtimer_sleeper;
# define rt_mutex_debug_check_no_locks_held(task) do { } while (0)
#endif

-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
- , .name = #mutexname, .file = __FILE__, .line = __LINE__
# define rt_mutex_init(mutex) \
do { \
raw_spin_lock_init(&(mutex)->wait_lock); \
__rt_mutex_init(mutex, #mutex); \
} while (0)

+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+ , .name = #mutexname, .file = __FILE__, .line = __LINE__
extern void rt_mutex_debug_task_free(struct task_struct *tsk);
#else
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
-# define rt_mutex_init(mutex) \
- do { \
- raw_spin_lock_init(&(mutex)->wait_lock); \
- __rt_mutex_init(mutex, #mutex); \
- } while (0)
# define rt_mutex_debug_task_free(t) do { } while (0)
#endif

diff --git a/kernel/locking/rt.c b/kernel/locking/rt.c
index 055a3df..90b8ba0 100644
--- a/kernel/locking/rt.c
+++ b/kernel/locking/rt.c
@@ -250,7 +250,7 @@ void __lockfunc rt_read_lock(rwlock_t *rwlock)
*/
if (rt_mutex_owner(lock) != current) {
migrate_disable();
- rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+ rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
__rt_spin_lock(lock);
}
rwlock->read_depth++;
@@ -366,6 +366,7 @@ void rt_down_write_nested_lock(struct rw_semaphore *rwsem,
rwsem_acquire_nest(&rwsem->dep_map, 0, 0, nest, _RET_IP_);
rt_mutex_lock(&rwsem->lock);
}
+EXPORT_SYMBOL(rt_down_write_nested_lock);

int rt_down_read_trylock(struct rw_semaphore *rwsem)
{
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 5c5cc76..fbf152b 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1552,7 +1552,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name)

debug_rt_mutex_init(lock, name);
}
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
+EXPORT_SYMBOL(__rt_mutex_init);

/**
* rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fc4da2d..112d4a5 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1682,28 +1682,22 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
* We can't schedule on offline CPUs, but it's not necessary
* since we can change their buffer sizes without any race.
*/
+ migrate_disable();
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
if (!cpu_buffer->nr_pages_to_update)
continue;

/* The update must run on the CPU that is being updated. */
- preempt_disable();
if (cpu == smp_processor_id() || !cpu_online(cpu)) {
rb_update_pages(cpu_buffer);
cpu_buffer->nr_pages_to_update = 0;
} else {
- /*
- * Can not disable preemption for schedule_work_on()
- * on PREEMPT_RT.
- */
- preempt_enable();
schedule_work_on(cpu,
&cpu_buffer->update_pages_work);
- preempt_disable();
}
- preempt_enable();
}
+ migrate_enable();

/* wait for all the updates to complete */
for_each_buffer_cpu(buffer, cpu) {
@@ -1740,22 +1734,16 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,

get_online_cpus();

- preempt_disable();
+ migrate_disable();
/* The update must run on the CPU that is being updated. */
if (cpu_id == smp_processor_id() || !cpu_online(cpu_id))
rb_update_pages(cpu_buffer);
else {
- /*
- * Can not disable preemption for schedule_work_on()
- * on PREEMPT_RT.
- */
- preempt_enable();
schedule_work_on(cpu_id,
&cpu_buffer->update_pages_work);
wait_for_completion(&cpu_buffer->update_done);
- preempt_disable();
}
- preempt_enable();
+ migrate_enable();

cpu_buffer->nr_pages_to_update = 0;
put_online_cpus();
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