[GIT PULL] core kernel fixes

From: Ingo Molnar
Date: Wed Sep 08 2010 - 09:04:36 EST


Linus,

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

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

Thanks,

Ingo

------------------>
Andi Kleen (1):
gcc-4.6: kernel/*: Fix unused but set warnings

Paul E. McKenney (2):
MAINTAINERS: Add RCU's public git tree
pid: make setpgid() system call use RCU read-side critical section

Randy Dunlap (1):
mutex: Fix annotations to include it in kernel-locking docbook


Documentation/DocBook/kernel-locking.tmpl | 6 ++++++
Documentation/mutex-design.txt | 3 ++-
MAINTAINERS | 2 ++
include/linux/mutex.h | 8 ++++++++
kernel/debug/kdb/kdb_bp.c | 2 --
kernel/hrtimer.c | 3 +--
kernel/mutex.c | 23 +++++++----------------
kernel/sched_fair.c | 3 +--
kernel/sys.c | 2 ++
kernel/sysctl.c | 5 +----
kernel/trace/ring_buffer.c | 2 --
11 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl
index 0b1a3f9..a0d479d 100644
--- a/Documentation/DocBook/kernel-locking.tmpl
+++ b/Documentation/DocBook/kernel-locking.tmpl
@@ -1961,6 +1961,12 @@ machines due to caching.
</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>

diff --git a/Documentation/mutex-design.txt b/Documentation/mutex-design.txt
index c91ccc0..38c10fd 100644
--- a/Documentation/mutex-design.txt
+++ b/Documentation/mutex-design.txt
@@ -9,7 +9,7 @@ firstly, there's nothing wrong with semaphores. But if the simpler
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.
@@ -136,3 +136,4 @@ the APIs of 'struct mutex' have been streamlined:
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);
diff --git a/MAINTAINERS b/MAINTAINERS
index 5fa8451..614861a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4799,6 +4799,7 @@ RCUTORTURE MODULE
M: Josh Triplett <josh@xxxxxxxxxxxxxxx>
M: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
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

@@ -4823,6 +4824,7 @@ M: Dipankar Sarma <dipankar@xxxxxxxxxx>
M: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
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*
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 878cab4..f363bc8 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -78,6 +78,14 @@ struct mutex_waiter {
# 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; \
diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
index 75bd9b3..20059ef 100644
--- a/kernel/debug/kdb/kdb_bp.c
+++ b/kernel/debug/kdb/kdb_bp.c
@@ -274,7 +274,6 @@ static int kdb_bp(int argc, const char **argv)
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 @@ static int kdb_bp(int argc, const char **argv)
/*
* 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;
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ce66917..1decafb 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1091,11 +1091,10 @@ EXPORT_SYMBOL_GPL(hrtimer_cancel);
*/
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);

diff --git a/kernel/mutex.c b/kernel/mutex.c
index 4c0b7b3..200407c 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -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 @@ EXPORT_SYMBOL(__mutex_init);
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 @@ EXPORT_SYMBOL(mutex_lock);

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 @@ __mutex_lock_killable_slowpath(atomic_t *lock_count);
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 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
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
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ab661eb..134f7ed 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1313,7 +1313,7 @@ static struct sched_group *
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 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,

if (local_group) {
this_load = avg_load;
- this = group;
} else if (avg_load < min_load) {
min_load = avg_load;
idlest = group;
diff --git a/kernel/sys.c b/kernel/sys.c
index e9ad444..7f5a0cd 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -931,6 +931,7 @@ SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
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 @@ SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
out:
/* All paths lead to here, thus we are safe. -DaveM */
write_unlock_irq(&tasklist_lock);
+ rcu_read_unlock();
return err;
}

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ca38e8e..f88552c 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1713,10 +1713,7 @@ static __init int sysctl_init(void)
{
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;
}
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 19cccc3..492197e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2985,13 +2985,11 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)

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.
--
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