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Commit 114e7b52 authored by Filipe Brandenburger's avatar Filipe Brandenburger Committed by Steven Rostedt
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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: default avatarFilipe Brandenburger <filbranden@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 5859fa1a

include/trace/ftrace.h

+4 −2
Original line number Diff line number Diff line
@@ -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;							\