Re: [PATCH 8/9] trace: use this_cpu_ptr per-cpu helper

[Christoph Lameter]

On Wed, 31 Oct 2012, Shan Wei wrote:

> From: Shan Wei <davidshan@xxxxxxxxxxx>
>
>
> Signed-off-by: Shan Wei <davidshan@xxxxxxxxxxx>
> ---
>  kernel/trace/blktrace.c |    2 +-
>  kernel/trace/trace.c    |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index c0bd030..71259e2 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -147,7 +147,7 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
>  		return;
>
>  	local_irq_save(flags);
> -	buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
> +	buf = this_cpu_ptr(bt->msg_data);
>  	va_start(args, fmt);
>  	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
>  	va_end(args);

Ok

> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 31e4f55..81ae35b 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -1513,7 +1513,7 @@ static char *get_trace_buf(void)
>  	if (!percpu_buffer)
>  		return NULL;
>
> -	buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
> +	buffer = this_cpu_ptr(percpu_buffer);
>
>  	return buffer->buffer;


Just do a

	return this_cpu_read(percpu_buffer->buffer);

and get rid of the this_cpu_ptr op
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