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authorOleg Nesterov <oleg@redhat.com>2019-04-23 14:07:24 +0200
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-05-28 09:05:23 -0700
commit95bf33b55ff4465399bad843f1d8d618c8baf1f3 (patch)
tree9ddcd2a9ed6f70a50a4ff6d7bc0c767b6dc98ae0 /kernel
parenta188339ca5a396acc588e5851ed7e19f66b0ebd9 (diff)
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rcu/sync: Kill rcu_sync_type/gp_type
Now that the RCU flavors have been consolidated, rcu_sync_type makes no sense because none of internal update functions aside from .held() depend on gp_type. This commit therefore removes this field and consolidates the relevant code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> [ paulmck: Added RCU and RCU-bh checks to rcu_sync_is_idle(). ] [ paulmck: And applied subsequent feedback from Oleg Nesterov. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/percpu-rwsem.c2
-rw-r--r--kernel/rcu/sync.c55
2 files changed, 6 insertions, 51 deletions
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index f17dad99eec8..48cab93a47fd 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -17,7 +17,7 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
return -ENOMEM;
/* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
- rcu_sync_init(&sem->rss, RCU_SCHED_SYNC);
+ rcu_sync_init(&sem->rss);
__init_rwsem(&sem->rw_sem, name, rwsem_key);
rcuwait_init(&sem->writer);
sem->readers_block = 0;
diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c
index a8304d90573f..ee427e138dad 100644
--- a/kernel/rcu/sync.c
+++ b/kernel/rcu/sync.c
@@ -10,65 +10,20 @@
#include <linux/rcu_sync.h>
#include <linux/sched.h>
-#ifdef CONFIG_PROVE_RCU
-#define __INIT_HELD(func) .held = func,
-#else
-#define __INIT_HELD(func)
-#endif
-
-static const struct {
- void (*sync)(void);
- void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
- void (*wait)(void);
-#ifdef CONFIG_PROVE_RCU
- int (*held)(void);
-#endif
-} gp_ops[] = {
- [RCU_SYNC] = {
- .sync = synchronize_rcu,
- .call = call_rcu,
- .wait = rcu_barrier,
- __INIT_HELD(rcu_read_lock_held)
- },
- [RCU_SCHED_SYNC] = {
- .sync = synchronize_rcu,
- .call = call_rcu,
- .wait = rcu_barrier,
- __INIT_HELD(rcu_read_lock_sched_held)
- },
- [RCU_BH_SYNC] = {
- .sync = synchronize_rcu,
- .call = call_rcu,
- .wait = rcu_barrier,
- __INIT_HELD(rcu_read_lock_bh_held)
- },
-};
-
enum { GP_IDLE = 0, GP_PENDING, GP_PASSED };
enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY };
#define rss_lock gp_wait.lock
-#ifdef CONFIG_PROVE_RCU
-void rcu_sync_lockdep_assert(struct rcu_sync *rsp)
-{
- RCU_LOCKDEP_WARN(!gp_ops[rsp->gp_type].held(),
- "suspicious rcu_sync_is_idle() usage");
-}
-
-EXPORT_SYMBOL_GPL(rcu_sync_lockdep_assert);
-#endif
-
/**
* rcu_sync_init() - Initialize an rcu_sync structure
* @rsp: Pointer to rcu_sync structure to be initialized
* @type: Flavor of RCU with which to synchronize rcu_sync structure
*/
-void rcu_sync_init(struct rcu_sync *rsp, enum rcu_sync_type type)
+void rcu_sync_init(struct rcu_sync *rsp)
{
memset(rsp, 0, sizeof(*rsp));
init_waitqueue_head(&rsp->gp_wait);
- rsp->gp_type = type;
}
/**
@@ -114,7 +69,7 @@ void rcu_sync_enter(struct rcu_sync *rsp)
WARN_ON_ONCE(need_wait && need_sync);
if (need_sync) {
- gp_ops[rsp->gp_type].sync();
+ synchronize_rcu();
rsp->gp_state = GP_PASSED;
wake_up_all(&rsp->gp_wait);
} else if (need_wait) {
@@ -167,7 +122,7 @@ static void rcu_sync_func(struct rcu_head *rhp)
* to catch a later GP.
*/
rsp->cb_state = CB_PENDING;
- gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
+ call_rcu(&rsp->cb_head, rcu_sync_func);
} else {
/*
* We're at least a GP after rcu_sync_exit(); eveybody will now
@@ -195,7 +150,7 @@ void rcu_sync_exit(struct rcu_sync *rsp)
if (!--rsp->gp_count) {
if (rsp->cb_state == CB_IDLE) {
rsp->cb_state = CB_PENDING;
- gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
+ call_rcu(&rsp->cb_head, rcu_sync_func);
} else if (rsp->cb_state == CB_PENDING) {
rsp->cb_state = CB_REPLAY;
}
@@ -220,7 +175,7 @@ void rcu_sync_dtor(struct rcu_sync *rsp)
spin_unlock_irq(&rsp->rss_lock);
if (cb_state != CB_IDLE) {
- gp_ops[rsp->gp_type].wait();
+ rcu_barrier();
WARN_ON_ONCE(rsp->cb_state != CB_IDLE);
}
}