On Thu, 12 Jun 2014 12:29:09 +0900, Masami Hiramatsu wrote: > NO, ftrace_lookup_ip() returns NULL if the hash is empty, so adding > !ftrace_hash_empty() is meaningless :) > > Actually, here I intended to have 3 meanings for the new/old_hash arguments, > - If it is NULL, it hits all > - If it is EMPTY_HASH, it hits nothing > - If it has some entries, it hits those entries. > > And in ftrace.c(__ftrace_hash_rec_update), AFAICS, ops->filter_hash has only > 2 meanings, > - If it is EMPTY_HASH or NULL, it hits all > - If it has some entries, it hits those entries.
Then I found an unrelated issue during review. It seems that checking NULL other_hash for the 'all' case in __ftrace_hash_rec_update() is not sufficient. It should check EMPTY_HASH case too, but then it ends up removing the check at all since it can be covered in ftrace_lookup_ip(). Thanks, Namhyung diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 13885590a184..8bd7aa69a479 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1545,7 +1545,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, * Only the filter_hash affects all records. * Update if the record is not in the notrace hash. */ - if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) + if (!ftrace_lookup_ip(other_hash, rec->ip)) match = 1; } else { in_hash = !!ftrace_lookup_ip(hash, rec->ip); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/