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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2018-04-05 17:19:17 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2018-05-15 10:27:56 -0700
commitf7194ac32ca241d28765a98e42a7fe13debc85a7 (patch)
tree788cdde1d2f7abe01e14b37004e89734cc642835 /kernel/rcu/srcutree.c
parent17672480fb1e953f999623b598a98130f8aacfbc (diff)
downloadlinux-f7194ac32ca241d28765a98e42a7fe13debc85a7.tar.bz2
srcu: Add cleanup_srcu_struct_quiesced()
The current cleanup_srcu_struct() flushes work, which prevents it from being invoked from some workqueue contexts, as well as from atomic (non-blocking) contexts. This patch therefore introduced a cleanup_srcu_struct_quiesced(), which can be invoked only after all activity on the specified srcu_struct has completed. This restriction allows cleanup_srcu_struct_quiesced() to be invoked from workqueue contexts as well as from atomic contexts. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Nitzan Carmi <nitzanc@mellanox.com> Tested-by: Nicholas Piggin <npiggin@gmail.com>
Diffstat (limited to 'kernel/rcu/srcutree.c')
-rw-r--r--kernel/rcu/srcutree.c30
1 files changed, 17 insertions, 13 deletions
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index fb560fca9ef4..b4123d7a2cec 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -366,24 +366,28 @@ static unsigned long srcu_get_delay(struct srcu_struct *sp)
return SRCU_INTERVAL;
}
-/**
- * cleanup_srcu_struct - deconstruct a sleep-RCU structure
- * @sp: structure to clean up.
- *
- * Must invoke this after you are finished using a given srcu_struct that
- * was initialized via init_srcu_struct(), else you leak memory.
- */
-void cleanup_srcu_struct(struct srcu_struct *sp)
+/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */
+void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)
{
int cpu;
if (WARN_ON(!srcu_get_delay(sp)))
- return; /* Leakage unless caller handles error. */
+ return; /* Just leak it! */
if (WARN_ON(srcu_readers_active(sp)))
- return; /* Leakage unless caller handles error. */
- flush_delayed_work(&sp->work);
+ return; /* Just leak it! */
+ if (quiesced) {
+ if (WARN_ON(delayed_work_pending(&sp->work)))
+ return; /* Just leak it! */
+ } else {
+ flush_delayed_work(&sp->work);
+ }
for_each_possible_cpu(cpu)
- flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work);
+ if (quiesced) {
+ if (WARN_ON(delayed_work_pending(&per_cpu_ptr(sp->sda, cpu)->work)))
+ return; /* Just leak it! */
+ } else {
+ flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work);
+ }
if (WARN_ON(rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
WARN_ON(srcu_readers_active(sp))) {
pr_info("%s: Active srcu_struct %p state: %d\n", __func__, sp, rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)));
@@ -392,7 +396,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp)
free_percpu(sp->sda);
sp->sda = NULL;
}
-EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
+EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
/*
* Counts the new reader in the appropriate per-CPU element of the