[tip:perf/core] tracing: Use this_cpu_ptr per-cpu helper

From: tip-bot for Shan Wei
Date: Thu Jan 24 2013 - 14:36:39 EST


Commit-ID: d8a0349c0cea477322c66ea9362f10c62fad5f62
Gitweb: http://git.kernel.org/tip/d8a0349c0cea477322c66ea9362f10c62fad5f62
Author: Shan Wei <davidshan@xxxxxxxxxxx>
AuthorDate: Tue, 13 Nov 2012 09:53:04 +0800
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Mon, 21 Jan 2013 13:22:30 -0500

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@xxxxxxxxx

Reviewed-by: Christoph Lameter <cl@xxxxxxxxx>
Signed-off-by: Shan Wei <davidshan@xxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
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 3c13e46..f8b7c62 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/