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ring-buffer: consolidate interface of rb_buffer_peek()

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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>
This commit is contained in:
Robert Richter 2009-07-31 14:58:04 +02:00 committed by Steven Rostedt
parent d28daf923a
commit d8eeb2d3b2
1 changed files with 4 additions and 7 deletions
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11
kernel/trace/ring_buffer.c
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@ -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);