diff options
| -rw-r--r-- | kernel/trace/ftrace.c | 55 |
1 files changed, 28 insertions, 27 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dcce0bf9c84..92b6fdf49ae 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -913,6 +913,7 @@ struct ftrace_hash { unsigned long size_bits; struct hlist_head *buckets; unsigned long count; + struct rcu_head rcu; }; /* @@ -1058,6 +1059,21 @@ static void free_ftrace_hash(struct ftrace_hash *hash) kfree(hash); } +static void __free_ftrace_hash_rcu(struct rcu_head *rcu) +{ + struct ftrace_hash *hash; + + hash = container_of(rcu, struct ftrace_hash, rcu); + free_ftrace_hash(hash); +} + +static void free_ftrace_hash_rcu(struct ftrace_hash *hash) +{ + if (!hash || hash == EMPTY_HASH) + return; + call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu); +} + static struct ftrace_hash *alloc_ftrace_hash(int size_bits) { struct ftrace_hash *hash; @@ -1122,7 +1138,8 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) struct ftrace_func_entry *entry; struct hlist_node *tp, *tn; struct hlist_head *hhd; - struct ftrace_hash *hash = *dst; + struct ftrace_hash *old_hash; + struct ftrace_hash *new_hash; unsigned long key; int size = src->count; int bits = 0; @@ -1133,13 +1150,11 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) * the empty_hash. */ if (!src->count) { - free_ftrace_hash(*dst); - *dst = EMPTY_HASH; + free_ftrace_hash_rcu(*dst); + rcu_assign_pointer(*dst, EMPTY_HASH); return 0; } - ftrace_hash_clear(hash); - /* * Make the hash size about 1/2 the # found */ @@ -1150,27 +1165,9 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) if (bits > FTRACE_HASH_MAX_BITS) bits = FTRACE_HASH_MAX_BITS; - /* We can't modify the empty_hash */ - if (hash == EMPTY_HASH) { - /* Create a new hash */ - *dst = alloc_ftrace_hash(bits); - if (!*dst) { - *dst = EMPTY_HASH; - return -ENOMEM; - } - hash = *dst; - } else { - size = 1 << bits; - - /* Use the old hash, but create new buckets */ - hhd = kzalloc(sizeof(*hhd) * size, GFP_KERNEL); - if (!hhd) - return -ENOMEM; - - kfree(hash->buckets); - hash->buckets = hhd; - hash->size_bits = bits; - } + new_hash = alloc_ftrace_hash(bits); + if (!new_hash) + return -ENOMEM; size = 1 << src->size_bits; for (i = 0; i < size; i++) { @@ -1181,10 +1178,14 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) else key = 0; remove_hash_entry(src, entry); - __add_hash_entry(hash, entry); + __add_hash_entry(new_hash, entry); } } + old_hash = *dst; + rcu_assign_pointer(*dst, new_hash); + free_ftrace_hash_rcu(old_hash); + return 0; } |