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tracing: Use this_cpu_ptr per-cpu helper

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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: Christoph Lameter <cl@linux.com>
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Shan Wei 2012-11-13 09:53:04 +08:00 • committed by Steven Rostedt
parent 771e03842a
commit d8a0349c0c
2 changed files with 2 additions and 5 deletions
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2
kernel/trace/blktrace.c
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@ -147,7 +147,7 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
return; return;
local_irq_save(flags); 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); va_start(args, fmt);
n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
va_end(args); va_end(args);

5
kernel/trace/trace.c
View file

@ -1517,7 +1517,6 @@ static struct trace_buffer_struct *trace_percpu_nmi_buffer;
static char *get_trace_buf(void) static char *get_trace_buf(void)
{ {
struct trace_buffer_struct *percpu_buffer; struct trace_buffer_struct *percpu_buffer;
struct trace_buffer_struct *buffer;
/* /*
* If we have allocated per cpu buffers, then we do not * If we have allocated per cpu buffers, then we do not
@ -1535,9 +1534,7 @@ static char *get_trace_buf(void)
if (!percpu_buffer) if (!percpu_buffer)
return NULL; return NULL;
buffer = per_cpu_ptr(percpu_buffer, smp_processor_id()); return this_cpu_ptr(&percpu_buffer->buffer[0]);
return buffer->buffer;
} }
static int alloc_percpu_trace_buffer(void) static int alloc_percpu_trace_buffer(void)