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| author | Filipe Brandenburger <filbranden@google.com> | 2014-02-28 21:32:17 -0800 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-03-07 10:06:11 -0500 |
| commit | 114e7b52dee69ce47dd55b8e520e0a48ba7cdae3 (patch) | |
| tree | d7ac31acb21d9427f0bbf87cd9b17c41b8df370b /include/trace/ftrace.h | |
| parent | 5859fa1a146ef5bf79953767f4ceb546fe4214b3 (diff) | |
| download | linux-114e7b52dee69ce47dd55b8e520e0a48ba7cdae3.tar.gz linux-114e7b52dee69ce47dd55b8e520e0a48ba7cdae3.tar.bz2 linux-114e7b52dee69ce47dd55b8e520e0a48ba7cdae3.zip | |
tracing: Evaluate len expression only once in __dynamic_array macro
Use a temporary variable to store the expansion of the len expression.
If the evaluation is expensive, this commit will ensure it is evaluated
only once inside ftrace_get_offsets_<call>.
Link: http://lkml.kernel.org/r/1393651938-16418-3-git-send-email-filbranden@google.com
Signed-off-by: Filipe Brandenburger <filbranden@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/trace/ftrace.h')
| -rw-r--r-- | include/trace/ftrace.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 21250056b7da..e15ae4010d51 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -361,10 +361,11 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \ #undef __dynamic_array #define __dynamic_array(type, item, len) \ + __item_length = (len) * sizeof(type); \ __data_offsets->item = __data_size + \ offsetof(typeof(*entry), __data); \ - __data_offsets->item |= ((len) * sizeof(type)) << 16; \ - __data_size += (len) * sizeof(type); + __data_offsets->item |= __item_length << 16; \ + __data_size += __item_length; #undef __string #define __string(item, src) __dynamic_array(char, item, \ @@ -376,6 +377,7 @@ static inline notrace int ftrace_get_offsets_##call( \ struct ftrace_data_offsets_##call *__data_offsets, proto) \ { \ int __data_size = 0; \ + int __maybe_unused __item_length; \ struct ftrace_raw_##call __maybe_unused *entry; \ \ tstruct; \ |