It is safe to aquire scheduler lock in rnp->lock since the rcu read lock is
always deadlock-immunity(rnp->lock is always can't be nested in scheduler lock)
it partial revert patch 016a8d5b.
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
kernel/rcutree.c | 17 ++---------------
kernel/rcutree.h | 1 -
2 files changed, 2 insertions(+), 16 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e08abb9..6c91edc 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1524,14 +1524,6 @@ static int __noreturn rcu_gp_kthread(void *arg)
}
}
-static void rsp_wakeup(struct irq_work *work)
-{
- struct rcu_state *rsp = container_of(work, struct rcu_state,
wakeup_work);
-
- /* Wake up rcu_gp_kthread() to start the grace period. */
- wake_up(&rsp->gp_wq);
-}
-
/*
* Start a new RCU grace period if warranted, re-initializing the hierarchy
* in preparation for detecting the next grace period. The caller must hold
@@ -1556,12 +1548,8 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct
rcu_node *rnp,
}
rsp->gp_flags = RCU_GP_FLAG_INIT;
- /*
- * We can't do wakeups while holding the rnp->lock, as that
- * could cause possible deadlocks with the rq->lock. Deter
- * the wakeup to interrupt context.
- */
- irq_work_queue(&rsp->wakeup_work);
+ /* Wake up rcu_gp_kthread() to start the grace period. */
+ wake_up(&rsp->gp_wq);
}
/*
@@ -3153,7 +3141,6 @@ static void __init rcu_init_one(struct rcu_state *rsp,
rsp->rda = rda;
init_waitqueue_head(&rsp->gp_wq);
- init_irq_work(&rsp->wakeup_work, rsp_wakeup);
rnp = rsp->level[rcu_num_lvls - 1];
for_each_possible_cpu(i) {
while (i > rnp->grphi)
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index a5e9643..5892a43 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -449,7 +449,6 @@ struct rcu_state {
char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
struct list_head flavors; /* List of RCU flavors. */
- struct irq_work wakeup_work; /* Postponed wakeups */
};
/* Values for rcu_state structure's gp_flags field. */
--
1.7.4.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
