Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-block.git] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f58c9ad15830777ded600f8af31138b31d17d172..2326b04c95c493fec48418746c0194980ad4b4fa 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1193,9 +1193,6 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
        struct list_head *p;
        unsigned i;
 
-       atomic_inc(&cpu_buffer->record_disabled);
-       synchronize_sched();
-
        spin_lock_irq(&cpu_buffer->reader_lock);
        rb_head_page_deactivate(cpu_buffer);
 
@@ -1211,12 +1208,9 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
                return;
 
        rb_reset_cpu(cpu_buffer);
-       spin_unlock_irq(&cpu_buffer->reader_lock);
-
        rb_check_pages(cpu_buffer);
 
-       atomic_dec(&cpu_buffer->record_disabled);
-
+       spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
 static void
@@ -1227,9 +1221,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
        struct list_head *p;
        unsigned i;
 
-       atomic_inc(&cpu_buffer->record_disabled);
-       synchronize_sched();
-
        spin_lock_irq(&cpu_buffer->reader_lock);
        rb_head_page_deactivate(cpu_buffer);
 
@@ -1242,11 +1233,9 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
                list_add_tail(&bpage->list, cpu_buffer->pages);
        }
        rb_reset_cpu(cpu_buffer);
-       spin_unlock_irq(&cpu_buffer->reader_lock);
-
        rb_check_pages(cpu_buffer);
 
-       atomic_dec(&cpu_buffer->record_disabled);
+       spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
 /**
@@ -1254,11 +1243,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
  * @buffer: the buffer to resize.
  * @size: the new size.
  *
- * The tracer is responsible for making sure that the buffer is
- * not being used while changing the size.
- * Note: We may be able to change the above requirement by using
- *  RCU synchronizations.
- *
  * Minimum size is 2 * BUF_PAGE_SIZE.
  *
  * Returns -1 on failure.
@@ -1290,6 +1274,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
        if (size == buffer_size)
                return size;
 
+       atomic_inc(&buffer->record_disabled);
+
+       /* Make sure all writers are done with this buffer. */
+       synchronize_sched();
+
        mutex_lock(&buffer->mutex);
        get_online_cpus();
 
@@ -1352,6 +1341,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
        put_online_cpus();
        mutex_unlock(&buffer->mutex);
 
+       atomic_dec(&buffer->record_disabled);
+
        return size;
 
  free_pages:
@@ -1361,6 +1352,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
        }
        put_online_cpus();
        mutex_unlock(&buffer->mutex);
+       atomic_dec(&buffer->record_disabled);
        return -ENOMEM;
 
        /*
@@ -1370,6 +1362,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
  out_fail:
        put_online_cpus();
        mutex_unlock(&buffer->mutex);
+       atomic_dec(&buffer->record_disabled);
        return -1;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_resize);