From f7194ac32ca241d28765a98e42a7fe13debc85a7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 5 Apr 2018 17:19:17 -0700 Subject: 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 Signed-off-by: Paul E. McKenney Tested-by: Nitzan Carmi Tested-by: Nicholas Piggin --- kernel/rcu/srcutree.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) (limited to 'kernel/rcu/srcutree.c') 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 -- cgit