diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-01-04 15:09:01 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-01-13 09:06:01 +0100 |
| commit | 559569acf94f538b56bd6eead80b439d6a78cdff (patch) | |
| tree | 36ff850b4bfd45cdeb102092f4cf00c48ca86434 | |
| parent | f96e9232e04856c781d4f71923a46dd3f7b429fa (diff) | |
| download | linux-559569acf94f538b56bd6eead80b439d6a78cdff.tar.bz2 | |
rcu: Adjust force_quiescent_state() locking, step 2
This patch releases rnp->lock after the end of
force_quiescent_state()'s switch statement. This is a second
step towards prohibiting starting grace periods while
force_quiescent_state() is executing, which will reduce the
number and complexity of races that force_quiescent_state() is
involved in.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12626465501994-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/rcutree.c | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index eae331da6bee..d42ad30c4d70 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1219,7 +1219,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_GP_IDLE: case RCU_GP_INIT: - spin_unlock(&rnp->lock); break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: @@ -1246,10 +1245,8 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->completed_fqs = lastcomp; forcenow = signaled == RCU_SAVE_COMPLETED; } - if (!forcenow) { - spin_unlock(&rnp->lock); + if (!forcenow) break; - } /* fall into next case. */ case RCU_FORCE_QS: @@ -1262,14 +1259,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Leave state in case more forcing is required. */ - break; - - default: - - spin_unlock(&rnp->lock); - WARN_ON_ONCE(1); + spin_lock(&rnp->lock); break; } + spin_unlock(&rnp->lock); unlock_fqs_ret: spin_unlock_irqrestore(&rsp->fqslock, flags); } |