From: Filipe Brandenburger Date: Sat, 1 Mar 2014 05:32:17 +0000 (-0800) Subject: tracing: Evaluate len expression only once in __dynamic_array macro X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=114e7b52dee69ce47dd55b8e520e0a48ba7cdae3;p=linux-beck.git 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_. Link: http://lkml.kernel.org/r/1393651938-16418-3-git-send-email-filbranden@google.com Signed-off-by: Filipe Brandenburger Signed-off-by: Steven Rostedt --- 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; \