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rcu_sync: Simplify rcu_sync using new rcu_sync_ops structure

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This commit adds the new struct rcu_sync_ops which holds sync/call
methods, and turns the function pointers in rcu_sync_struct into an array
of struct rcu_sync_ops.  This simplifies the "init" helpers by collapsing
a switch statement and explicit multiple definitions into a simple
assignment and a helper macro, respectively.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Oleg Nesterov
2015-08-21 19:42:47 +02:00
committed by Paul E. McKenney
parent cc44ca848f
commit 82e8c565be
2 changed files with 45 additions and 57 deletions
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42
kernel/rcu/sync.c
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@@ -23,6 +23,24 @@
#include <linux/rcu_sync.h>
#include <linux/sched.h>
static const struct {
void (*sync)(void);
void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
} gp_ops[] = {
[RCU_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
},
[RCU_SCHED_SYNC] = {
.sync = synchronize_sched,
.call = call_rcu_sched,
},
[RCU_BH_SYNC] = {
.sync = synchronize_rcu_bh,
.call = call_rcu_bh,
},
};
enum { GP_IDLE = 0, GP_PENDING, GP_PASSED };
enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY };
@@ -37,23 +55,7 @@ void rcu_sync_init(struct rcu_sync *rsp, enum rcu_sync_type type)
{
memset(rsp, 0, sizeof(*rsp));
init_waitqueue_head(&rsp->gp_wait);
switch (type) {
case RCU_SYNC:
rsp->sync = synchronize_rcu;
rsp->call = call_rcu;
break;
case RCU_SCHED_SYNC:
rsp->sync = synchronize_sched;
rsp->call = call_rcu_sched;
break;
case RCU_BH_SYNC:
rsp->sync = synchronize_rcu_bh;
rsp->call = call_rcu_bh;
break;
}
rsp->gp_type = type;
}
/**
@@ -85,7 +87,7 @@ void rcu_sync_enter(struct rcu_sync *rsp)
BUG_ON(need_wait && need_sync);
if (need_sync) {
rsp->sync();
gp_ops[rsp->gp_type].sync();
rsp->gp_state = GP_PASSED;
wake_up_all(&rsp->gp_wait);
} else if (need_wait) {
@@ -138,7 +140,7 @@ static void rcu_sync_func(struct rcu_head *rcu)
* to catch a later GP.
*/
rsp->cb_state = CB_PENDING;
rsp->call(&rsp->cb_head, rcu_sync_func);
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else {
/*
* We're at least a GP after rcu_sync_exit(); eveybody will now
@@ -166,7 +168,7 @@ void rcu_sync_exit(struct rcu_sync *rsp)
if (!--rsp->gp_count) {
if (rsp->cb_state == CB_IDLE) {
rsp->cb_state = CB_PENDING;
rsp->call(&rsp->cb_head, rcu_sync_func);
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else if (rsp->cb_state == CB_PENDING) {
rsp->cb_state = CB_REPLAY;
}