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ring-buffer: do not swap if recording is disabled

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If the ring buffer recording has been disabled. Do not let
swapping of ring buffers occur. Simply return -EAGAIN.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2009-01-21 15:24:56 -05:00 committed by Ingo Molnar
parent 5bc4564b22
commit 97b17efe45
2 changed files with 16 additions and 1 deletions
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15
kernel/trace/ring_buffer.c
View File

@ -2266,9 +2266,24 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
if (buffer_a->pages != buffer_b->pages)
return -EINVAL;
if (ring_buffer_flags != RB_BUFFERS_ON)
return -EAGAIN;
if (atomic_read(&buffer_a->record_disabled))
return -EAGAIN;
if (atomic_read(&buffer_b->record_disabled))
return -EAGAIN;
cpu_buffer_a = buffer_a->buffers[cpu];
cpu_buffer_b = buffer_b->buffers[cpu];
if (atomic_read(&cpu_buffer_a->record_disabled))
return -EAGAIN;
if (atomic_read(&cpu_buffer_b->record_disabled))
return -EAGAIN;
/*
* We can't do a synchronize_sched here because this
* function can be called in atomic context.

2
kernel/trace/trace.c
View File

@ -415,7 +415,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
ftrace_enable_cpu();
WARN_ON_ONCE(ret);
WARN_ON_ONCE(ret && ret != -EAGAIN);
__update_max_tr(tr, tsk, cpu);
__raw_spin_unlock(&ftrace_max_lock);