Messages in this thread Patch in this message | | | From | Patrick Palka <> | Subject | [PATCH] ring-buffer: use atomic_[set|clear]_mask in place of a cmpxchg loop | Date | Wed, 15 Oct 2014 09:41:40 -0400 |
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Instead of open-coding the equivalent cmpxchg loop we can just use atomic_set_mask and atomic_clear_mask to atomically OR or AND the value in &buffer->record_disabled.
Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Patrick Palka <patrick@parcs.ath.cx> ---
NB: I have only tested this patch on x86_64 by booting with CONFIG_RING_BUFFER_STARTUP_TEST=y.
kernel/trace/ring_buffer.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 2d75c94..e15ce2a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3050,13 +3050,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_enable); */ void ring_buffer_record_off(struct ring_buffer *buffer) { - unsigned int rd; - unsigned int new_rd; - - do { - rd = atomic_read(&buffer->record_disabled); - new_rd = rd | RB_BUFFER_OFF; - } while (atomic_cmpxchg(&buffer->record_disabled, rd, new_rd) != rd); + atomic_set_mask(RB_BUFFER_OFF, &buffer->record_disabled); } EXPORT_SYMBOL_GPL(ring_buffer_record_off); @@ -3073,13 +3067,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_off); */ void ring_buffer_record_on(struct ring_buffer *buffer) { - unsigned int rd; - unsigned int new_rd; - - do { - rd = atomic_read(&buffer->record_disabled); - new_rd = rd & ~RB_BUFFER_OFF; - } while (atomic_cmpxchg(&buffer->record_disabled, rd, new_rd) != rd); + atomic_clear_mask(RB_BUFFER_OFF, &buffer->record_disabled); } EXPORT_SYMBOL_GPL(ring_buffer_record_on); -- 2.1.2.443.g670a3c1
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