Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: gcc-4.6: kernel/*: Fix unused but set warnings mutex: Fix annotations to include it in kernel-locking docbook pid: make setpgid() system call use RCU read-side critical section MAINTAINERS: Add RCU's public git tree

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
…/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: gcc-4.6: kernel/*: Fix unused but set warnings mutex: Fix annotations to include it in kernel-locking docbook pid: make setpgid() system call use RCU read-side critical section MAINTAINERS: Add RCU's public git tree
Linus Torvalds
2 parents 899edae615 b3bd3de66f
Showing 11 changed files Side-by-side Diff
Documentation/DocBook/kernel-locking.tmpl
Documentation/mutex-design.txt
MAINTAINERS
include/linux/mutex.h
kernel/debug/kdb/kdb_bp.c
kernel/hrtimer.c
kernel/mutex.c
kernel/sched_fair.c
kernel/sys.c
kernel/sysctl.c
kernel/trace/ring_buffer.c
@@ -1961,6 +1961,12 @@
    </sect1>
   </chapter>
  
+  <chapter id="apiref">
+   <title>Mutex API reference</title>
+!Iinclude/linux/mutex.h
+!Ekernel/mutex.c
+  </chapter>
+
   <chapter id="references">
    <title>Further reading</title>
  
@@ -9,7 +9,7 @@
 mutex semantics are sufficient for your code, then there are a couple
 of advantages of mutexes:
  
- - 'struct mutex' is smaller on most architectures: .e.g on x86,
+ - 'struct mutex' is smaller on most architectures: E.g. on x86,
    'struct semaphore' is 20 bytes, 'struct mutex' is 16 bytes.
    A smaller structure size means less RAM footprint, and better
    CPU-cache utilization.
@@ -136,4 +136,5 @@
  void mutex_lock_nested(struct mutex *lock, unsigned int subclass);
  int  mutex_lock_interruptible_nested(struct mutex *lock,
                                       unsigned int subclass);
+ int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
@@ -4810,6 +4810,7 @@
 M:	Josh Triplett <josh@freedesktop.org>
 M:	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
 S:	Supported
+T:	git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
 F:	Documentation/RCU/torture.txt
 F:	kernel/rcutorture.c
  
@@ -4834,6 +4835,7 @@
 M:	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
 W:	http://www.rdrop.com/users/paulmck/rclock/
 S:	Supported
+T:	git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
 F:	Documentation/RCU/
 F:	include/linux/rcu*
 F:	include/linux/srcu*
@@ -78,6 +78,14 @@
 # include <linux/mutex-debug.h>
 #else
 # define __DEBUG_MUTEX_INITIALIZER(lockname)
+/**
+ * mutex_init - initialize the mutex
+ * @mutex: the mutex to be initialized
+ *
+ * Initialize the mutex to unlocked state.
+ *
+ * It is not allowed to initialize an already locked mutex.
+ */
 # define mutex_init(mutex) \
 do {							\
 	static struct lock_class_key __key;		\
@@ -274,7 +274,6 @@
 	int i, bpno;
 	kdb_bp_t *bp, *bp_check;
 	int diag;
-	int free;
 	char *symname = NULL;
 	long offset = 0ul;
 	int nextarg;
@@ -305,7 +304,6 @@
 	/*
 	 * Find an empty bp structure to allocate
 	 */
-	free = KDB_MAXBPT;
 	for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
 		if (bp->bp_free)
 			break;
@@ -1091,11 +1091,10 @@
  */
 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
 {
-	struct hrtimer_clock_base *base;
 	unsigned long flags;
 	ktime_t rem;
  
-	base = lock_hrtimer_base(timer, &flags);
+	lock_hrtimer_base(timer, &flags);
 	rem = hrtimer_expires_remaining(timer);
 	unlock_hrtimer_base(timer, &flags);
  
@@ -36,15 +36,6 @@
 # include <asm/mutex.h>
 #endif
  
-/***
- * mutex_init - initialize the mutex
- * @lock: the mutex to be initialized
- * @key: the lock_class_key for the class; used by mutex lock debugging
- *
- * Initialize the mutex to unlocked state.
- *
- * It is not allowed to initialize an already locked mutex.
- */
 void
 __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
 {
@@ -68,7 +59,7 @@
 static __used noinline void __sched
 __mutex_lock_slowpath(atomic_t *lock_count);
  
-/***
+/**
  * mutex_lock - acquire the mutex
  * @lock: the mutex to be acquired
  *
@@ -105,7 +96,7 @@
  
 static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
  
-/***
+/**
  * mutex_unlock - release the mutex
  * @lock: the mutex to be released
  *
@@ -364,8 +355,8 @@
 static noinline int __sched
 __mutex_lock_interruptible_slowpath(atomic_t *lock_count);
  
-/***
- * mutex_lock_interruptible - acquire the mutex, interruptable
+/**
+ * mutex_lock_interruptible - acquire the mutex, interruptible
  * @lock: the mutex to be acquired
  *
  * Lock the mutex like mutex_lock(), and return 0 if the mutex has
  
@@ -456,15 +447,15 @@
 	return prev == 1;
 }
  
-/***
- * mutex_trylock - try acquire the mutex, without waiting
+/**
+ * mutex_trylock - try to acquire the mutex, without waiting
  * @lock: the mutex to be acquired
  *
  * Try to acquire the mutex atomically. Returns 1 if the mutex
  * has been acquired successfully, and 0 on contention.
  *
  * NOTE: this function follows the spin_trylock() convention, so
- * it is negated to the down_trylock() return values! Be careful
+ * it is negated from the down_trylock() return values! Be careful
  * about this when converting semaphore users to mutexes.
  *
  * This function must not be used in interrupt context. The
@@ -1313,7 +1313,7 @@
 find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 		  int this_cpu, int load_idx)
 {
-	struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
+	struct sched_group *idlest = NULL, *group = sd->groups;
 	unsigned long min_load = ULONG_MAX, this_load = 0;
 	int imbalance = 100 + (sd->imbalance_pct-100)/2;
  
@@ -1348,7 +1348,6 @@
  
 		if (local_group) {
 			this_load = avg_load;
-			this = group;
 		} else if (avg_load < min_load) {
 			min_load = avg_load;
 			idlest = group;
@@ -931,6 +931,7 @@
 		pgid = pid;
 	if (pgid < 0)
 		return -EINVAL;
+	rcu_read_lock();
  
 	/* From this point forward we keep holding onto the tasklist lock
 	 * so that our parent does not change from under us. -DaveM
@@ -984,6 +985,7 @@
 out:
 	/* All paths lead to here, thus we are safe. -DaveM */
 	write_unlock_irq(&tasklist_lock);
+	rcu_read_unlock();
 	return err;
 }
  
@@ -1713,10 +1713,7 @@
 {
 	sysctl_set_parent(NULL, root_table);
 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
-	{
-		int err;
-		err = sysctl_check_table(current->nsproxy, root_table);
-	}
+	sysctl_check_table(current->nsproxy, root_table);
 #endif
 	return 0;
 }
@@ -2985,13 +2985,11 @@
  
 static void rb_advance_iter(struct ring_buffer_iter *iter)
 {
-	struct ring_buffer *buffer;
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct ring_buffer_event *event;
 	unsigned length;
  
 	cpu_buffer = iter->cpu_buffer;
-	buffer = cpu_buffer->buffer;
  
 	/*
 	 * Check if we are at the end of the buffer.
...	...	@@ -1961,6 +1961,12 @@
1961	1961	</sect1>
1962	1962	</chapter>
1963	1963
	1964	+ <chapter id="apiref">
	1965	+ <title>Mutex API reference</title>
	1966	+!Iinclude/linux/mutex.h
	1967	+!Ekernel/mutex.c
	1968	+ </chapter>
	1969	+
1964	1970	<chapter id="references">
1965	1971	<title>Further reading</title>
1966	1972
...	...	@@ -9,7 +9,7 @@
9	9	mutex semantics are sufficient for your code, then there are a couple
10	10	of advantages of mutexes:
11	11
12		- - 'struct mutex' is smaller on most architectures: .e.g on x86,
	12	+ - 'struct mutex' is smaller on most architectures: E.g. on x86,
13	13	'struct semaphore' is 20 bytes, 'struct mutex' is 16 bytes.
14	14	A smaller structure size means less RAM footprint, and better
15	15	CPU-cache utilization.
...	...	@@ -136,4 +136,5 @@
136	136	void mutex_lock_nested(struct mutex *lock, unsigned int subclass);
137	137	int mutex_lock_interruptible_nested(struct mutex *lock,
138	138	unsigned int subclass);
	139	+ int atomic_dec_and_mutex_lock(atomic_t cnt, struct mutex lock);
...	...	@@ -4810,6 +4810,7 @@
4810	4810	M: Josh Triplett <josh@freedesktop.org>
4811	4811	M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
4812	4812	S: Supported
	4813	+T: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
4813	4814	F: Documentation/RCU/torture.txt
4814	4815	F: kernel/rcutorture.c
4815	4816
...	...	@@ -4834,6 +4835,7 @@
4834	4835	M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
4835	4836	W: http://www.rdrop.com/users/paulmck/rclock/
4836	4837	S: Supported
	4838	+T: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
4837	4839	F: Documentation/RCU/
4838	4840	F: include/linux/rcu*
4839	4841	F: include/linux/srcu*
...	...	@@ -78,6 +78,14 @@
78	78	# include <linux/mutex-debug.h>
79	79	#else
80	80	# define __DEBUG_MUTEX_INITIALIZER(lockname)
	81	+/**
	82	+ * mutex_init - initialize the mutex
	83	+ * @mutex: the mutex to be initialized
	84	+ *
	85	+ * Initialize the mutex to unlocked state.
	86	+ *
	87	+ * It is not allowed to initialize an already locked mutex.
	88	+ */
81	89	# define mutex_init(mutex) \
82	90	do { \
83	91	static struct lock_class_key __key; \
...	...	@@ -274,7 +274,6 @@
274	274	int i, bpno;
275	275	kdb_bp_t bp, bp_check;
276	276	int diag;
277		- int free;
278	277	char *symname = NULL;
279	278	long offset = 0ul;
280	279	int nextarg;
...	...	@@ -305,7 +304,6 @@
305	304	/*
306	305	* Find an empty bp structure to allocate
307	306	*/
308		- free = KDB_MAXBPT;
309	307	for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
310	308	if (bp->bp_free)
311	309	break;
...	...	@@ -1091,11 +1091,10 @@
1091	1091	*/
1092	1092	ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1093	1093	{
1094		- struct hrtimer_clock_base *base;
1095	1094	unsigned long flags;
1096	1095	ktime_t rem;
1097	1096
1098		- base = lock_hrtimer_base(timer, &flags);
	1097	+ lock_hrtimer_base(timer, &flags);
1099	1098	rem = hrtimer_expires_remaining(timer);
1100	1099	unlock_hrtimer_base(timer, &flags);
1101	1100
...	...	@@ -36,15 +36,6 @@
36	36	# include <asm/mutex.h>
37	37	#endif
38	38
39		-/***
40		- * mutex_init - initialize the mutex
41		- * @lock: the mutex to be initialized
42		- * @key: the lock_class_key for the class; used by mutex lock debugging
43		- *
44		- * Initialize the mutex to unlocked state.
45		- *
46		- * It is not allowed to initialize an already locked mutex.
47		- */
48	39	void
49	40	__mutex_init(struct mutex lock, const char name, struct lock_class_key *key)
50	41	{
...	...	@@ -68,7 +59,7 @@
68	59	static __used noinline void __sched
69	60	__mutex_lock_slowpath(atomic_t *lock_count);
70	61
71		-/***
	62	+/**
72	63	* mutex_lock - acquire the mutex
73	64	* @lock: the mutex to be acquired
74	65	*
...	...	@@ -105,7 +96,7 @@
105	96
106	97	static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
107	98
108		-/***
	99	+/**
109	100	* mutex_unlock - release the mutex
110	101	* @lock: the mutex to be released
111	102	*
...	...	@@ -364,8 +355,8 @@
364	355	static noinline int __sched
365	356	__mutex_lock_interruptible_slowpath(atomic_t *lock_count);
366	357
367		-/***
368		- * mutex_lock_interruptible - acquire the mutex, interruptable
	358	+/**
	359	+ * mutex_lock_interruptible - acquire the mutex, interruptible
369	360	* @lock: the mutex to be acquired
370	361	*
371	362	* Lock the mutex like mutex_lock(), and return 0 if the mutex has
372	363
...	...	@@ -456,15 +447,15 @@
456	447	return prev == 1;
457	448	}
458	449
459		-/***
460		- * mutex_trylock - try acquire the mutex, without waiting
	450	+/**
	451	+ * mutex_trylock - try to acquire the mutex, without waiting
461	452	* @lock: the mutex to be acquired
462	453	*
463	454	* Try to acquire the mutex atomically. Returns 1 if the mutex
464	455	* has been acquired successfully, and 0 on contention.
465	456	*
466	457	* NOTE: this function follows the spin_trylock() convention, so
467		- * it is negated to the down_trylock() return values! Be careful
	458	+ * it is negated from the down_trylock() return values! Be careful
468	459	* about this when converting semaphore users to mutexes.
469	460	*
470	461	* This function must not be used in interrupt context. The
...	...	@@ -1313,7 +1313,7 @@
1313	1313	find_idlest_group(struct sched_domain sd, struct task_struct p,
1314	1314	int this_cpu, int load_idx)
1315	1315	{
1316		- struct sched_group idlest = NULL, this = NULL, *group = sd->groups;
	1316	+ struct sched_group idlest = NULL, group = sd->groups;
1317	1317	unsigned long min_load = ULONG_MAX, this_load = 0;
1318	1318	int imbalance = 100 + (sd->imbalance_pct-100)/2;
1319	1319
...	...	@@ -1348,7 +1348,6 @@
1348	1348
1349	1349	if (local_group) {
1350	1350	this_load = avg_load;
1351		- this = group;
1352	1351	} else if (avg_load < min_load) {
1353	1352	min_load = avg_load;
1354	1353	idlest = group;
...	...	@@ -931,6 +931,7 @@
931	931	pgid = pid;
932	932	if (pgid < 0)
933	933	return -EINVAL;
	934	+ rcu_read_lock();
934	935
935	936	/* From this point forward we keep holding onto the tasklist lock
936	937	* so that our parent does not change from under us. -DaveM
...	...	@@ -984,6 +985,7 @@
984	985	out:
985	986	/* All paths lead to here, thus we are safe. -DaveM */
986	987	write_unlock_irq(&tasklist_lock);
	988	+ rcu_read_unlock();
987	989	return err;
988	990	}
989	991
...	...	@@ -1713,10 +1713,7 @@
1713	1713	{
1714	1714	sysctl_set_parent(NULL, root_table);
1715	1715	#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1716		- {
1717		- int err;
1718		- err = sysctl_check_table(current->nsproxy, root_table);
1719		- }
	1716	+ sysctl_check_table(current->nsproxy, root_table);
1720	1717	#endif
1721	1718	return 0;
1722	1719	}