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>

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 454e74e..8786c35 100644 (file)
--- 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);