linux-stable/kernel/locking
Hou Tao e6b1a44ecc locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.

However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.

Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.

If any such is reported, we can consider alternative solutions.

Fixes: 70fe2f4815 ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
2020-09-16 16:26:56 +02:00
..
lock_events.c locking/lock_events: Don't show pvqspinlock events on bare metal 2019-04-10 10:56:05 +02:00
lock_events.h locking/lock_events: Use raw_cpu_{add,inc}() for stats 2019-06-03 12:32:56 +02:00
lock_events_list.h locking/rwsem: Adaptive disabling of reader optimistic spinning 2019-06-17 12:28:09 +02:00
lockdep.c locking/lockdep: Fix "USED" <- "IN-NMI" inversions 2020-09-03 11:19:42 +02:00
lockdep_internals.h locking/lockdep: Fix "USED" <- "IN-NMI" inversions 2020-09-03 11:19:42 +02:00
lockdep_proc.c locking/lockdep: Fix overflow in presentation of average lock-time 2020-07-25 21:47:42 +02:00
lockdep_states.h locking/lockdep: Rework FS_RECLAIM annotation 2017-08-10 12:29:03 +02:00
locktorture.c This tree adds the sched_set_fifo*() encapsulation APIs to remove 2020-08-06 11:55:43 -07:00
Makefile kcsan: Make KCSAN compatible with lockdep 2020-03-21 09:41:16 +01:00
mcs_spinlock.h locking/mcs: Use smp_cond_load_acquire() in MCS spin loop 2018-04-27 09:48:49 +02:00
mutex-debug.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
mutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mutex.c Revert "locking/mutex: Complain upon mutex API misuse in IRQ contexts" 2019-12-11 00:27:43 +01:00
mutex.h mutex: Fix up mutex_waiter usage 2019-08-08 09:09:25 +02:00
osq_lock.c locking/osq_lock: Annotate a data race in osq_lock 2020-06-29 12:04:48 -07:00
percpu-rwsem.c locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count 2020-09-16 16:26:56 +02:00
qrwlock.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock.c x86/kvm: Add "nopvspin" parameter to disable PV spinlocks 2020-07-08 16:21:57 -04:00
qspinlock_paravirt.h Revert "locking/pvqspinlock: Don't wait if vCPU is preempted" 2019-09-25 10:22:37 +02:00
qspinlock_stat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
rtmutex-debug.c kernel: rename show_stack_loglvl() => show_stack() 2020-06-09 09:39:13 -07:00
rtmutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex.c locking/rtmutex: Remove unused rt_mutex_cmpxchg_relaxed() 2020-04-27 12:26:40 +02:00
rtmutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex_common.h locking/rtmutex: Handle non enqueued waiters gracefully in remove_waiter() 2018-03-28 23:01:30 +02:00
rwsem.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
rwsem.h locking/percpu-rwsem: Remove the embedded rwsem 2020-02-11 13:10:56 +01:00
semaphore.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436 2019-06-05 17:37:17 +02:00
spinlock.c asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
spinlock_debug.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
test-ww_mutex.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9 2019-05-21 11:28:40 +02:00