Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751274AbaJONlv (ORCPT ); Wed, 15 Oct 2014 09:41:51 -0400 Received: from mail-qc0-f175.google.com ([209.85.216.175]:49840 "EHLO mail-qc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbaJONlu (ORCPT ); Wed, 15 Oct 2014 09:41:50 -0400 From: Patrick Palka To: linux-kernel@vger.kernel.org Cc: Patrick Palka , Steven Rostedt , Ingo Molnar Subject: [PATCH] ring-buffer: use atomic_[set|clear]_mask in place of a cmpxchg loop Date: Wed, 15 Oct 2014 09:41:40 -0400 Message-Id: <1413380500-3914-1-git-send-email-patrick@parcs.ath.cx> X-Mailer: git-send-email 2.1.2.443.g670a3c1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Ingo Molnar Signed-off-by: Patrick Palka --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/