From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754158AbcCRXiB (ORCPT ); Fri, 18 Mar 2016 19:38:01 -0400 Received: from p3plsmtps2ded01.prod.phx3.secureserver.net ([208.109.80.58]:59005 "EHLO p3plsmtps2ded01.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753407AbcCRXht (ORCPT ); Fri, 18 Mar 2016 19:37:49 -0400 x-originating-ip: 72.167.245.219 From: "K. Y. Srinivasan" To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.c Cc: "K. Y. Srinivasan" Subject: [PATCH 2/5] Drivers: hv: vmbus: Use READ_ONCE() to read variables that are volatile Date: Fri, 18 Mar 2016 18:14:22 -0700 Message-Id: <1458350065-32666-2-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1458350065-32666-1-git-send-email-kys@microsoft.com> References: <1458350038-32624-1-git-send-email-kys@microsoft.com> <1458350065-32666-1-git-send-email-kys@microsoft.com> X-CMAE-Envelope: MS4wfDuEFjVjLsCdWx6eJKXxJnQjkYbEwhIc9qYIB/ZIErtgZqIsGCKQ3LvVnSsBBDCqireZSM7/LCSwcjo3B7fR+Cy3MZS8t8ZjVwsLDVc0HWTUBpC8MrNH f9q1RWtIxpXRsj3y/Wmh+FGZ4Y/SdUbE/SZNLjv0bAUp4KQfKbPUd50J2Cwrub6PwYjhxAe2v60Je3Mb3ElVHZ+S6BwQ/agYERhLQbzKFL2pSBjXNzuK0Tek qNwGx+8WjtJyTwkak1DMKNTLt4ChhgakvROZCz2nSCV62/aLCvdRkY5d5i6cbZFtNxdMtk5oNW7JVFdoFFRzWJ0cvAFpU6bi8ruVmUylG5jgnyBk9fXarC/n V/EO68/zANregcgX+a1E2UU43qOlHXUrBuqn2xmYUuhZe9zg9g8A8N/BrPw0zhqY7zpCZJQd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the READ_ONCE macro to access variabes that can change asynchronously. Signed-off-by: K. Y. Srinivasan --- drivers/hv/ring_buffer.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 902375b..2919395 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -69,7 +69,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi) static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi) { mb(); - if (rbi->ring_buffer->interrupt_mask) + if (READ_ONCE(rbi->ring_buffer->interrupt_mask)) return false; /* check interrupt_mask before read_index */ @@ -78,7 +78,7 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi) * This is the only case we need to signal when the * ring transitions from being empty to non-empty. */ - if (old_write == rbi->ring_buffer->read_index) + if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) return true; return false; @@ -102,8 +102,9 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi) static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi) { u32 cur_write_sz; - u32 pending_sz = rbi->ring_buffer->pending_send_sz; + u32 pending_sz; + pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); /* If the other end is not blocked on write don't bother. */ if (pending_sz == 0) return false; -- 1.7.4.1