Shan Wei said, at 2012/11/13 9:53:
> From: Shan Wei <davids...@tencent.com>
>
> typeof(&buffer) is a pointer to array of 1024 char, or char (*)[1024].
> But, typeof(&buffer[0]) is a pointer to char which match the return type of
> get_trace_buf().
> As well-known, the value of &buffer is equal to &buffer[0].
> so return this_cpu_ptr(&percpu_buffer->buffer[0]) can avoid type cast.
>
> Signed-off-by: Shan Wei <davids...@tencent.com>
Steven Rostedt, would you like to pick it up to your tree?
> ---
> v4: avoid type cast using &percpu_buffer->buffer[0].
> ---
> kernel/trace/blktrace.c | 2 +-
> kernel/trace/trace.c | 5 +----
> 2 files changed, 2 insertions(+), 5 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);
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 31e4f55..65cb003 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -1495,7 +1495,6 @@ static struct trace_buffer_struct
> *trace_percpu_nmi_buffer;
> static char *get_trace_buf(void)
> {
> struct trace_buffer_struct *percpu_buffer;
> - struct trace_buffer_struct *buffer;
>
> /*
> * If we have allocated per cpu buffers, then we do not
> @@ -1513,9 +1512,7 @@ static char *get_trace_buf(void)
> if (!percpu_buffer)
> return NULL;
>
> - buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
> -
> - return buffer->buffer;
> + return this_cpu_ptr(&percpu_buffer->buffer[0]);
> }
>
> static int alloc_percpu_trace_buffer(void)
>
--
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