core/locking changes for v3.1

Linus,

Please pull the latest core-locking-for-linus git tree from:

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-locking-for-linus

 Thanks,

       Ingo

------------------>
Anton Blanchard (1):
     lockup detector: Fix reference to the non-existent CONFIG_DETECT_SOFTLOCKUP option

Dima Zavin (1):
     plist: Remove the need to supply locks to plist heads

Jean Delvare (1):
     mutex: Make mutex_destroy() an inline function

Peter Zijlstra (1):
     lockdep: Fix lockdep_no_validate against IRQ states

 include/linux/mutex.h   |    2 +-
 include/linux/plist.h   |   55 ++-------------------------------------------- include/linux/rtmutex.h |    4 +-
 kernel/fork.c           |    2 +-
 kernel/futex.c          |    2 +-
 kernel/lockdep.c        |    3 ++
 kernel/pm_qos_params.c  |    6 ++--
 kernel/rtmutex.c        |    2 +-
 kernel/sched.c          |    4 +-
 lib/Kconfig.debug       |    4 +-
 lib/plist.c             |    7 +-----

 11 files changed, 20 insertions(+), 71 deletions(-)

include/linux/mutex.h +1 -1

index a940fe4..7f87217 100644
@@ -92,7 +92,7 @@ do {                                                  \
                                                        \
        __mutex_init((mutex), #mutex, &__key);          \
  } while (0)
-# define mutex_destroy(mutex)                          do { } while (0)
+static inline void mutex_destroy(struct mutex *lock) {}
  #endif
 
  #ifdef CONFIG_DEBUG_LOCK_ALLOC

include/linux/plist.h +2 -32

index c9b9f32..aa0fb39 100644
@@ -77,14 +77,9 @@
 
  #include <linux/kernel.h>
  #include <linux/list.h>
-#include <linux/spinlock_types.h>
 
  struct plist_head {
        struct list_head node_list;
-#ifdef CONFIG_DEBUG_PI_LIST
-       raw_spinlock_t *rawlock;
-       spinlock_t *spinlock;
-#endif
  };
 
  struct plist_node {

@@ -93,37 +88,13 @@ struct plist_node {
        struct list_head        node_list;
  };
 
-#ifdef CONFIG_DEBUG_PI_LIST
-# define PLIST_HEAD_LOCK_INIT(_lock)           .spinlock = _lock
-# define PLIST_HEAD_LOCK_INIT_RAW(_lock)       .rawlock = _lock
-#else
-# define PLIST_HEAD_LOCK_INIT(_lock)
-# define PLIST_HEAD_LOCK_INIT_RAW(_lock)
-#endif
-
-#define _PLIST_HEAD_INIT(head)                         \
-       .node_list = LIST_HEAD_INIT((head).node_list)
-
  /**
  * PLIST_HEAD_INIT - static struct plist_head initializer
  * @head:      struct plist_head variable name
- * @_lock:     lock to initialize for this list
- */
-#define PLIST_HEAD_INIT(head, _lock)                   \
-{                                                      \
-       _PLIST_HEAD_INIT(head),                         \
-       PLIST_HEAD_LOCK_INIT(&(_lock))                  \
-}
-
-/**
- * PLIST_HEAD_INIT_RAW - static struct plist_head initializer
- * @head:      struct plist_head variable name
- * @_lock:     lock to initialize for this list
  */
-#define PLIST_HEAD_INIT_RAW(head, _lock)               \
+#define PLIST_HEAD_INIT(head)                          \
  {                                                      \
-       _PLIST_HEAD_INIT(head),                         \
-       PLIST_HEAD_LOCK_INIT_RAW(&(_lock))              \
+       .node_list = LIST_HEAD_INIT((head).node_list)   \
  }
 
  /**

@@ -141,31 +112,11 @@ struct plist_node {
  /**
  * plist_head_init - dynamic struct plist_head initializer
  * @head:      &struct plist_head pointer
- * @lock:      spinlock protecting the list (debugging)
  */

 static inline void

include/linux/plist.h +1 -1

-plist_head_init(struct plist_head *head, spinlock_t *lock)
+plist_head_init(struct plist_head *head)

 {
       INIT_LIST_HEAD(&head->node_list);

include/linux/plist.h +0 -19

-#ifdef CONFIG_DEBUG_PI_LIST
-       head->spinlock = lock;
-       head->rawlock = NULL;
-#endif
-}
-
-/**
- * plist_head_init_raw - dynamic struct plist_head initializer
- * @head:      &struct plist_head pointer
- * @lock:      raw_spinlock protecting the list (debugging)
- */
-static inline void
-plist_head_init_raw(struct plist_head *head, raw_spinlock_t *lock)
-{
-       INIT_LIST_HEAD(&head->node_list);
-#ifdef CONFIG_DEBUG_PI_LIST
-       head->rawlock = lock;
-       head->spinlock = NULL;
-#endif

 }

 /**

include/linux/rtmutex.h +2 -2

index 8d522ff..de17134 100644
@@ -66,7 +66,7 @@ struct hrtimer_sleeper;
 
  #define __RT_MUTEX_INITIALIZER(mutexname) \
        { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
-       , .wait_list = PLIST_HEAD_INIT_RAW(mutexname.wait_list, mutexname.wait_lock) \
+       , .wait_list = PLIST_HEAD_INIT(mutexname.wait_list) \
        , .owner = NULL \
        __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
 

@@ -100,7 +100,7 @@ extern void rt_mutex_unlock(struct rt_mutex *lock);
 
  #ifdef CONFIG_RT_MUTEXES
  # define INIT_RT_MUTEXES(tsk)                                          \
-       .pi_waiters     = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
+       .pi_waiters     = PLIST_HEAD_INIT(tsk.pi_waiters),      \
        INIT_RT_MUTEX_DEBUG(tsk)
  #else
  # define INIT_RT_MUTEXES(tsk)

kernel/fork.c +1 -1

index 0276c30..7517a53 100644
@@ -1013,7 +1013,7 @@ static void rt_mutex_init_task(struct task_struct *p)
  {
        raw_spin_lock_init(&p->pi_lock);
  #ifdef CONFIG_RT_MUTEXES
-       plist_head_init_raw(&p->pi_waiters, &p->pi_lock);
+       plist_head_init(&p->pi_waiters);
        p->pi_blocked_on = NULL;
  #endif
  }

kernel/futex.c +1 -1

index fe28dc2..3fbc76c 100644
@@ -2697,7 +2697,7 @@ static int __init futex_init(void)
                futex_cmpxchg_enabled = 1;
 
        for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
-               plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
+               plist_head_init(&futex_queues[i].chain);
                spin_lock_init(&futex_queues[i].lock);
        }
 

kernel/lockdep.c +3 -0

index 298c927..628276d 100644
@@ -2468,6 +2468,9 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark)
 
                BUG_ON(usage_bit >= LOCK_USAGE_STATES);
 
+               if (hlock_class(hlock)->key == &__lockdep_no_validate__)
+                       continue;
+
                if (!mark_lock(curr, hlock, usage_bit))
                        return 0;
        }

kernel/pm_qos_params.c +3 -3

index 6824ca7..37f05d0 100644
@@ -74,7 +74,7 @@ static DEFINE_SPINLOCK(pm_qos_lock);
  static struct pm_qos_object null_pm_qos;
  static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
  static struct pm_qos_object cpu_dma_pm_qos = {
-       .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
+       .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests),
        .notifiers = &cpu_dma_lat_notifier,
        .name = "cpu_dma_latency",
        .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,

@@ -84,7 +84,7 @@ static struct pm_qos_object cpu_dma_pm_qos = {
 
  static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
  static struct pm_qos_object network_lat_pm_qos = {
-       .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
+       .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests),
        .notifiers = &network_lat_notifier,
        .name = "network_latency",
        .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,

@@ -95,7 +95,7 @@ static struct pm_qos_object network_lat_pm_qos = {
 
  static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
  static struct pm_qos_object network_throughput_pm_qos = {
-       .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
+       .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests),
        .notifiers = &network_throughput_notifier,
        .name = "network_throughput",
        .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,

kernel/rtmutex.c +1 -1

index ab44911..255e166 100644
@@ -890,7 +890,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name)
  {
        lock->owner = NULL;
        raw_spin_lock_init(&lock->wait_lock);
-       plist_head_init_raw(&lock->wait_list, &lock->wait_lock);
+       plist_head_init(&lock->wait_list);
 
        debug_rt_mutex_init(lock, name);
  }

kernel/sched.c +2 -2

index 3f2e502..71bc127 100644
@@ -7781,7 +7781,7 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
  #ifdef CONFIG_SMP
        rt_rq->rt_nr_migratory = 0;
        rt_rq->overloaded = 0;
-       plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock);
+       plist_head_init(&rt_rq->pushable_tasks);
  #endif
 
        rt_rq->rt_time = 0;

@@ -7986,7 +7986,7 @@ void __init sched_init(void)
  #endif
 
  #ifdef CONFIG_RT_MUTEXES
-       plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock);
+       plist_head_init(&init_task.pi_waiters);
  #endif
 
        /*

lib/Kconfig.debug +0 -0

index dd373c8..9c28fa4 100644
@@ -227,7 +227,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE

 config DETECT_HUNG_TASK
       bool "Detect Hung Tasks"
       depends on DEBUG_KERNEL
-       default DETECT_SOFTLOCKUP
+       default LOCKUP_DETECTOR
       help
         Say Y here to enable the kernel to detect "hung tasks", which are bugs that cause the task to be stuck in

lib/Kconfig.debug +0 -0

@@ -866,7 +866,7 @@ config BOOT_PRINTK_DELAY

         system, and then set "lpj=M" before setting "boot_delay=N".
         NOTE:  Using this option may adversely affect SMP systems. I.e., processors other than the first one may not boot up.
-         BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
+         BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect what it believes to be lockup conditions.

 config RCU_TORTURE_TEST

lib/plist.c +1 -7

index 0ae7e64..a0a4da4 100644
@@ -56,11 +56,6 @@ static void plist_check_list(struct list_head *top)
 
  static void plist_check_head(struct plist_head *head)
  {
-       WARN_ON(head != &test_head && !head->rawlock && !head->spinlock);
-       if (head->rawlock)
-               WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));
-       if (head->spinlock)
-               WARN_ON_SMP(!spin_is_locked(head->spinlock));
        if (!plist_head_empty(head))
                plist_check_list(&plist_first(head)->prio_list);
        plist_check_list(&head->node_list);

@@ -180,7 +175,7 @@ static int  __init plist_test(void)
        unsigned int r = local_clock();
 
        printk(KERN_INFO "start plist test\n");
-       plist_head_init(&test_head, NULL);
+       plist_head_init(&test_head);
        for (i = 0; i < ARRAY_SIZE(test_node); i++)
                plist_node_init(test_node + i, 0);
 
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Quoted 3 lines

Peter Zijlstra (1):
lockdep: Fix lockdep_no_validate against IRQ states

from today's master, this last commit triggers:

/src/linux/linux/kernel/lockdep.c: In function 'mark_held_locks':
/src/linux/linux/kernel/lockdep.c:2471:31: warning: comparison of distinct pointer types lacks a cast

I'm not sure if both struct member and variable's type are correct nor the comparability between struct lockdep_subclass_key *' and struct lock_class_key *'. So I'll let you fix this.

Argh, I really need -Werror to even see warnings, compiler output just flies by waaaaaay too fast.

Quoted 3 lines · Peter Zijlstra

Argh, I really need -Werror to even see warnings, compiler output just flies by waaaaaay too fast.

Do what I do:

make -j32 > ../makes

that way the only thing you see is the warnings (and the final link report).

That pattern was one reason why I wanted me default compile to be warning-clean. Of course, then gcc started adding more warnings, and it's not clean any more ("warning: statement with no effect" from the fact that we just define many functions to '(0)' when they are disabled) but my current personal compile config only gets four warnings.

I realize there are *many* more warnings once you start enabling more special code - as usual, the core code tends to be better quality, and the further away from that base you get, the worse things get.

But it would definitely be good if most kernel developers did the above. Do it for just your personal config - at least you'll see the warnings in code you write (because presumably your personal config will have that code enabled ;)

..
net/netfilter/nf_conntrack_core.c: In function ‘nf_conntrack_init’:
net/netfilter/nf_conntrack_core.c:1579:3: warning: the comparison will always evaluate as ‘true’ for the address of ‘nf_conntrack_attach’ will never be NULL [-Waddress]

Quoted 5 lines · Ingo Molnar

..
net/netfilter/nf_conntrack_core.c: In function ‘nf_conntrack_init’:
net/netfilter/nf_conntrack_core.c:1579:3: warning: the comparison will always evaluate as ‘true’ for the address of ‘nf_conntrack_attach’ will never be NULL [-Waddress]

These all seem to be essentially compiler bugs.

We have macros that do generic things (in this case "rcu_assign_pointer()" and tests their values. The fact that the tests sometimes end up being statically true (or false) is not something the compiler should complain about - it should use it to optimize the code.

Sad.

We can make a compiler bug-report, or disable -Waddress. Or maybe we can write the tests in a way that doesn't trigger the compiler bug.

This same issue is why I hated -Wsign-compare. Some of the things gcc complained about were just technically moronic. So compiler warnings are not always a good thing.

Quoted 15 lines · Linus Torvalds

Quoted 5 lines · Ingo Molnar

..
net/netfilter/nf_conntrack_core.c: In function ‘nf_conntrack_init’:
net/netfilter/nf_conntrack_core.c:1579:3: warning: the comparison will always evaluate as ‘true’ for the address of ‘nf_conntrack_attach’ will never be NULL [-Waddress]

These all seem to be essentially compiler bugs.

We have macros that do generic things (in this case "rcu_assign_pointer()" and tests their values. The fact that the tests sometimes end up being statically true (or false) is not something the compiler should complain about - it should use it to optimize the code.

Quoted 8 lines

Sad.

We can make a compiler bug-report, or disable -Waddress. Or maybe we can write the tests in a way that doesn't trigger the compiler bug.

This same issue is why I hated -Wsign-compare. Some of the things gcc complained about were just technically moronic. So compiler warnings are not always a good thing.

With -Wno-address added (see the first patch below) it looks a lot more useful:

aldebaran:~/linux/linux> make -j32 >e sound/pci/hda/patch_sigmatel.c: In function ‘stac92xx_init’:
sound/pci/hda/patch_sigmatel.c:4385:3: warning: statement with no effect [-Wunused-value]
sound/pci/hda/patch_sigmatel.c: In function ‘stac92xx_resume’:
sound/pci/hda/patch_sigmatel.c:4925:3: warning: statement with no effect [-Wunused-value]
sound/pci/hda/patch_realtek.c: In function ‘alc_init’:
sound/pci/hda/patch_realtek.c:4176:2: warning: statement with no effect [-Wunused-value]
sound/pci/hda/patch_realtek.c: In function ‘alc_resume’:
sound/pci/hda/patch_realtek.c:4558:2: warning: statement with no effect [-Wunused-value]
sound/pci/hda/hda_codec.c: In function ‘snd_hda_mixer_amp_switch_put’:
sound/pci/hda/hda_codec.c:2320:2: warning: statement with no effect [-Wunused-value]
sound/pci/hda/patch_realtek.c: In function ‘alc269_resume’:
sound/pci/hda/patch_realtek.c:14878:2: warning: statement with no effect [-Wunused-value]
drivers/md/dm.c: In function ‘split_bvec’:
drivers/md/dm.c:1052:3: warning: statement with no effect [-Wunused-value]
drivers/md/dm.c: In function ‘clone_bio’:
drivers/md/dm.c:1079:3: warning: statement with no effect [-Wunused-value]
drivers/md/dm-table.c: In function ‘dm_table_set_integrity’:
drivers/md/dm-table.c:1193:2: warning: statement with no effect [-Wunused-value]
Setup is 15260 bytes (padded to 15360 bytes).
System is 4654 kB
CRC 6d1b94ea

those unused-x warnings seem legit and should be fixed. For example the second patch below fixed the dm.c warnings.

That's with:

 gcc version 4.6.0 20110509 (Red Hat 4.6.0-7) (GCC)

so a reasonably recent GCC. I think we should kill -Waddress.

Thanks,

       Ingo

Makefile +0 -0

index d018956..e651294 100644
@@ -559,9 +559,9 @@ endif # $(dot-config)

 all: vmlinux

 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE

Makefile +1 -1

-KBUILD_CFLAGS  += -Os
+KBUILD_CFLAGS  += -Os -Wno-address

 else

Makefile +1 -1

-KBUILD_CFLAGS  += -O2
+KBUILD_CFLAGS  += -O2 -Wno-address

 endif

 include $(srctree)/arch/$(SRCARCH)/Makefile

include/linux/bio.h +0 -0

index ce33e68..283250a 100644

Quoted 5 lines · Ingo Molnar

..
net/netfilter/nf_conntrack_core.c: In function ‘nf_conntrack_init’:
net/netfilter/nf_conntrack_core.c:1579:3: warning: the comparison will always evaluate as ‘true’ for the address of ‘nf_conntrack_attach’ will never be NULL [-Waddress]

These all seem to be essentially compiler bugs.

We have macros that do generic things (in this case "rcu_assign_pointer()" and tests their values. The fact that the tests sometimes end up being statically true (or false) is not something the compiler should complain about - it should use it to optimize the code.

Sad.

We can make a compiler bug-report, or disable -Waddress. Or maybe we can write the tests in a way that doesn't trigger the compiler bug.

This same issue is why I hated -Wsign-compare. Some of the things gcc complained about were just technically moronic. So compiler warnings are not always a good thing.

                 Linus

/src/linux/linux/kernel/lockdep.c: In function 'mark_held_locks':
/src/linux/linux/kernel/lockdep.c:2471:31: warning: comparison of distinct pointer types lacks a cast