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Commit ef2fbe16 authored by Namhyung Kim's avatar Namhyung Kim Committed by Steven Rostedt
Browse files

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: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 1f61be00

kernel/trace/ftrace.c

+7 −5
Original line number Diff line number Diff line
@@ -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;