diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4140d0ce25f1..256b5e07c39a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1883,7 +1883,24 @@ static bool ftrace_hash_rec_enable(struct ftrace_ops *ops) return __ftrace_hash_rec_update(ops, true); } -static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, int inc) +/* + * This function will update what functions @ops traces when its filter + * changes. + * + * The @inc states if the @ops callbacks are going to be added or removed. + * When one of the @ops hashes are updated to a "new_hash" the dyn_ftrace + * records are update via: + * + * ftrace_hash_rec_disable_modify(ops); + * ops->hash = new_hash + * ftrace_hash_rec_enable_modify(ops); + * + * Where the @ops is removed from all the records it is tracing using + * its old hash. The @ops hash is updated to the new hash, and then + * the @ops is added back to the records so that it is tracing all + * the new functions. + */ +static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, bool inc) { struct ftrace_ops *op; @@ -1907,12 +1924,12 @@ static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, int inc) static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops) { - ftrace_hash_rec_update_modify(ops, 0); + ftrace_hash_rec_update_modify(ops, false); } static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops) { - ftrace_hash_rec_update_modify(ops, 1); + ftrace_hash_rec_update_modify(ops, true); } /*