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Commit d8a0349c authored by Shan Wei's avatar Shan Wei Committed by Steven Rostedt
Browse files

tracing: Use this_cpu_ptr per-cpu helper 

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.

Link: http://lkml.kernel.org/r/50A1A800.3020102@gmail.com



Reviewed-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarShan Wei <davidshan@tencent.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 771e0384

kernel/trace/blktrace.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/trace/trace.c

+1 −4
Original line number Diff line number Diff line
@@ -1517,7 +1517,6 @@ 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
@@ -1535,9 +1534,7 @@ 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)