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From: "K. Y. Srinivasan" <kys@microsoft.com>
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" <kys@microsoft.com>, stable@vger.kernel.org
Subject: [PATCH 3/5] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal_on_read()
Date: Fri, 18 Mar 2016 18:14:23 -0700	[thread overview]
Message-ID: <1458350065-32666-3-git-send-email-kys@microsoft.com> (raw)
In-Reply-To: <1458350065-32666-1-git-send-email-kys@microsoft.com>

We need to issue a full memory barrier prior making a signalling decision.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
---
 drivers/hv/ring_buffer.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 2919395..67dc245 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -104,6 +104,7 @@ static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
 	u32 cur_write_sz;
 	u32 pending_sz;
 
+	mb();
 	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)
-- 
1.7.4.1

  parent reply	other threads:[~2016-03-18 23:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-19  1:13 [PATCH 0/5] Drivers: hv: vmbus K. Y. Srinivasan
2016-03-19  1:14 ` [PATCH 1/5] Drivers: hv: vmbus: Introduce functions for estimating room in the ring buffer K. Y. Srinivasan
2016-03-19  1:14   ` [PATCH 2/5] Drivers: hv: vmbus: Use READ_ONCE() to read variables that are volatile K. Y. Srinivasan
2016-03-19  1:14   ` K. Y. Srinivasan [this message]
2016-03-21  8:19     ` [PATCH 3/5] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal_on_read() Vitaly Kuznetsov
2016-03-22  0:04       ` KY Srinivasan
2016-03-22  9:55         ` Vitaly Kuznetsov
2016-03-22 14:37           ` KY Srinivasan
2016-03-22 17:11           ` KY Srinivasan
2016-03-19  1:14   ` [PATCH 4/5] Drivers: hv: vmbus: Use the new virt_xx barrier code K. Y. Srinivasan
2016-03-19  1:14   ` [PATCH 5/5] Drivers: hv: vmbus: Implement copy-free read APIs K. Y. Srinivasan
2016-03-21  8:29     ` Vitaly Kuznetsov
2016-03-21 23:42       ` KY Srinivasan
2016-03-23 19:43 ` [PATCH 0/5] Drivers: hv: vmbus KY Srinivasan

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