From 3a518b76af7bb411efe6dd090fbf098e29accb2e Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 21 Aug 2015 19:42:50 +0200 Subject: rcu_sync: Add CONFIG_PROVE_RCU checks This commit validates that the caller of rcu_sync_is_idle() holds the corresponding type of RCU read-side lock, but only in kernels built with CONFIG_PROVE_RCU=y. This validation is carried out via a new rcu_sync_ops->held() method that is checked within rcu_sync_is_idle(). Note that although this does add code to the fast path, it only does so in kernels built with CONFIG_PROVE_RCU=y. Suggested-by: "Paul E. McKenney" Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/sync.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel/rcu/sync.c') diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c index 5a9aa4c394f1..01c9807a7f73 100644 --- a/kernel/rcu/sync.c +++ b/kernel/rcu/sync.c @@ -23,21 +23,33 @@ #include #include +#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 *)); +#ifdef CONFIG_PROVE_RCU + int (*held)(void); +#endif } gp_ops[] = { [RCU_SYNC] = { .sync = synchronize_rcu, .call = call_rcu, + __INIT_HELD(rcu_read_lock_held) }, [RCU_SCHED_SYNC] = { .sync = synchronize_sched, .call = call_rcu_sched, + __INIT_HELD(rcu_read_lock_sched_held) }, [RCU_BH_SYNC] = { .sync = synchronize_rcu_bh, .call = call_rcu_bh, + __INIT_HELD(rcu_read_lock_bh_held) }, }; @@ -46,6 +58,14 @@ enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY }; #define rss_lock gp_wait.lock +#ifdef CONFIG_PROVE_RCU +bool __rcu_sync_is_idle(struct rcu_sync *rsp) +{ + WARN_ON(!gp_ops[rsp->gp_type].held()); + return rsp->gp_state == GP_IDLE; +} +#endif + /** * rcu_sync_init() - Initialize an rcu_sync structure * @rsp: Pointer to rcu_sync structure to be initialized -- cgit v1.2.3