Peter Zijlstra 8d53fa1904 locking/qspinlock: Clarify xchg_tail() ordering ...

While going over the code I noticed that xchg_tail() is a RELEASE but
had no obvious pairing commented.

It pairs with a somewhat unique address dependency through
decode_tail().

So the store-release of xchg_tail() is paired by the address
dependency of the load of xchg_tail followed by the dereference from
the pointer computed from that load.

The @old -> @prev transformation itself is pure, and therefore does
not depend on external state, so that is immaterial wrt. ordering.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <waiman.long@hpe.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2016-06-08 14:44:00 +02:00

..

lglock.c

sched/stop_machine: Fix deadlock between multiple stop_two_cpus()

2015-06-19 10:03:12 +02:00

lockdep_internals.h

lockdep: Increase static allocations

2014-04-18 14:20:50 +02:00

lockdep_proc.c

lockdep: Fix lock_chain::base size

2016-04-23 13:53:03 +02:00

lockdep_states.h

…

lockdep.c

locking/lockdep: Use __jhash_mix() for iterate_chain_key()

2016-06-08 14:22:00 +02:00

locktorture.c

lcoking/locktorture: Simplify the torture_runnable computation

2016-04-28 10:57:51 +02:00

Makefile

kernel: add kcov code coverage

2016-03-22 15:36:02 -07:00

mcs_spinlock.h

locking/mcs: Fix mcs_spin_lock() ordering

2016-02-29 10:02:41 +01:00

mutex-debug.c

mutex: Always clear owner field upon mutex_unlock()

2015-01-09 11:20:39 +01:00

mutex-debug.h

locking/mutex: Set and clear owner using WRITE_ONCE()

2016-06-03 12:06:10 +02:00

mutex.c

locking/ww_mutex: Report recursive ww_mutex locking early

2016-06-03 08:37:26 +02:00

mutex.h

locking/mutex: Set and clear owner using WRITE_ONCE()

2016-06-03 12:06:10 +02:00

osq_lock.c

locking/osq: Fix ordering of node initialisation in osq_lock

2015-12-17 11:40:29 -08:00

percpu-rwsem.c

ext4: fix races between changing inode journal mode and ext4_writepages

2016-04-25 23:22:35 -04:00

qrwlock.c

locking/qrwlock: Rename ->lock to ->wait_lock

2015-09-18 09:27:29 +02:00

qspinlock_paravirt.h

locking/pvqspinlock: Enable slowpath locking count tracking

2016-02-29 10:02:42 +01:00

qspinlock_stat.h

locking/pvqspinlock: Robustify init_qspinlock_stat()

2016-05-05 09:58:51 +02:00

qspinlock.c

locking/qspinlock: Clarify xchg_tail() ordering

2016-06-08 14:44:00 +02:00

rtmutex_common.h

rtmutex: Delete scriptable tester

2015-07-20 11:45:45 +02:00

rtmutex-debug.c

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rtmutex-debug.h

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rtmutex.c

locking/rtmutex: Only warn once on a trylock from bad context

2016-06-08 14:22:00 +02:00

rtmutex.h

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rwsem-spinlock.c

locking/rwsem: Introduce basis for down_write_killable()

2016-04-13 10:42:20 +02:00

rwsem-xadd.c

locking/rwsem: Optimize write lock by reducing operations in slowpath

2016-06-03 09:47:13 +02:00

rwsem.c

add down_write_killable_nested()

2016-05-26 00:04:58 -04:00

rwsem.h

locking/rwsem: Set lock ownership ASAP

2015-02-18 16:57:13 +01:00

semaphore.c

locking/semaphore: Resolve some shadow warnings

2014-09-04 07:17:24 +02:00

spinlock_debug.c

locking: Move the spinlock code to kernel/locking/

2013-11-06 07:55:21 +01:00

spinlock.c

spinlock: Add spin_lock_bh_nested()

2015-01-03 14:32:57 -05:00