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locking/percpu-rwsem, lockdep: Make percpu-rwsem use its own lockdep_map

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As preparation for replacing the embedded rwsem, give percpu-rwsem its
own lockdep_map.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/20200131151539.927625541@infradead.org
This commit is contained in:
Peter Zijlstra
2019-10-30 20:01:26 +01:00
committed by Ingo Molnar
parent 810507fe6f
commit 1751060e25
5 changed files with 37 additions and 18 deletions
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16
kernel/locking/percpu-rwsem.c
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@@ -11,7 +11,7 @@
#include "rwsem.h"
int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
const char *name, struct lock_class_key *rwsem_key)
const char *name, struct lock_class_key *key)
{
sem->read_count = alloc_percpu(int);
if (unlikely(!sem->read_count))
@@ -19,9 +19,13 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
/* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
rcu_sync_init(&sem->rss);
__init_rwsem(&sem->rw_sem, name, rwsem_key);
init_rwsem(&sem->rw_sem);
rcuwait_init(&sem->writer);
sem->readers_block = 0;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
debug_check_no_locks_freed((void *)sem, sizeof(*sem));
lockdep_init_map(&sem->dep_map, name, key, 0);
#endif
return 0;
}
EXPORT_SYMBOL_GPL(__percpu_init_rwsem);
@@ -142,10 +146,12 @@ static bool readers_active_check(struct percpu_rw_semaphore *sem)
void percpu_down_write(struct percpu_rw_semaphore *sem)
{
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
/* Notify readers to take the slow path. */
rcu_sync_enter(&sem->rss);
down_write(&sem->rw_sem);
__down_write(&sem->rw_sem);
/*
* Notify new readers to block; up until now, and thus throughout the
@@ -168,6 +174,8 @@ EXPORT_SYMBOL_GPL(percpu_down_write);
void percpu_up_write(struct percpu_rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, _RET_IP_);
/*
* Signal the writer is done, no fast path yet.
*
@@ -183,7 +191,7 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
/*
* Release the write lock, this will allow readers back in the game.
*/
up_write(&sem->rw_sem);
__up_write(&sem->rw_sem);
/*
* Once this completes (at least one RCU-sched grace period hence) the