ring-buffer: consolidate interface of rb_buffer_peek()

rb_buffer_peek() operates with struct ring_buffer_per_cpu *cpu_buffer
only. Thus, instead of passing variables buffer and cpu it is better
to use cpu_buffer directly. This also reduces the risk of races since
cpu_buffer is not calculated twice.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1249045084-3028-1-git-send-email-robert.richter@amd.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 4 insertions, 7 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 454e74e718cf..8786c350b4ca 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2997,15 +2997,12 @@ static void rb_advance_iter(struct ring_buffer_iter *iter)
 }
 
 static struct ring_buffer_event *
-rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
+rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts)
 {
-        struct ring_buffer_per_cpu *cpu_buffer;
         struct ring_buffer_event *event;
         struct buffer_page *reader;
         int nr_loops = 0;
 
-        cpu_buffer = buffer->buffers[cpu];
-
  again:
         /*
          * We repeat when a timestamp is encountered. It is possible
@@ -3049,7 +3046,7 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
         case RINGBUF_TYPE_DATA:
                 if (ts) {
                         *ts = cpu_buffer->read_stamp + event->time_delta;
-                        ring_buffer_normalize_time_stamp(buffer,
+                        ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
                                                          cpu_buffer->cpu, ts);
                 }
                 return event;
@@ -3168,7 +3165,7 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
         local_irq_save(flags);
         if (dolock)
                 spin_lock(&cpu_buffer->reader_lock);
-        event = rb_buffer_peek(buffer, cpu, ts);
+        event = rb_buffer_peek(cpu_buffer, ts);
         if (event && event->type_len == RINGBUF_TYPE_PADDING)
                 rb_advance_reader(cpu_buffer);
         if (dolock)
@@ -3237,7 +3234,7 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
         if (dolock)
                 spin_lock(&cpu_buffer->reader_lock);
 
-        event = rb_buffer_peek(buffer, cpu, ts);
+        event = rb_buffer_peek(cpu_buffer, ts);
         if (event)
                 rb_advance_reader(cpu_buffer);