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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 <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Namhyung Kim 2014-06-11 17:06:54 +09:00 committed by Steven Rostedt
parent 1f61be007e
commit ef2fbe16ac
1 changed files with 7 additions and 5 deletions
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12
kernel/trace/ftrace.c
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@ -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;