From: Namhyung Kim Date: Wed, 11 Jun 2014 08:06:54 +0000 (+0900) Subject: ftrace: Do not copy hash if O_TRUNC is set X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=ef2fbe16ac176c21e3b3013c169e6fdb71ec56c7;p=deliverable%2Flinux.git ftrace: Do not copy hash if O_TRUNC is set When a filter file is open for writing and O_TRUNC is set, there's no need to copy and free the filter entries. Link: http://lkml.kernel.org/p/1402474014-28655-2-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index e14ff4c1713e..232b898eebbd 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3010,7 +3010,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, hash = ops->filter_hash; if (file->f_mode & FMODE_WRITE) { - iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash); + const int size_bits = FTRACE_HASH_DEFAULT_BITS; + + if (file->f_flags & O_TRUNC) + iter->hash = alloc_ftrace_hash(size_bits); + else + iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); + if (!iter->hash) { trace_parser_put(&iter->parser); kfree(iter); @@ -3019,10 +3025,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, } } - if ((file->f_mode & FMODE_WRITE) && - (file->f_flags & O_TRUNC)) - ftrace_filter_reset(iter->hash); - if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start;