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From:   Dexuan Cui <decui@microsoft.com>
To:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>
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        "driverdev-devel@linuxdriverproject.org" 
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        Haiyang Zhang <haiyangz@microsoft.com>,
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        "vkuznets@redhat.com" <vkuznets@redhat.com>,
        "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
        Dexuan Cui <decui@microsoft.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: [PATCH] Drivers: hv: vmbus: do not mark HV_PCIE as perf_device
Thread-Topic: [PATCH] Drivers: hv: vmbus: do not mark HV_PCIE as perf_device
Thread-Index: AQHTsoWxPZWSmwkLCUq7k/Ya55+f/A==
Date:   Sat, 3 Mar 2018 00:22:19 +0000
Message-ID: <20180303002155.20689-2-decui@microsoft.com>
References: <20180303002155.20689-1-decui@microsoft.com>
In-Reply-To: <20180303002155.20689-1-decui@microsoft.com>
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The pci-hyperv driver's channel callback hv_pci_onchannelcallback() is not
really a hot path, so we don't need to mark it as a perf_device, meaning
with this patch all HV_PCIE channels' target_cpu will be CPU0.

This patch can help to avoid a potential ABBA deadlock in the busy loop
of Hyper-V PCI driver's hv_compose_msi_msg().

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel_mgmt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index c21020b69114..55ee5e87073a 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -71,7 +71,7 @@ static const struct vmbus_device vmbus_devs[] =3D {
 	/* PCIE */
 	{ .dev_type =3D HV_PCIE,
 	  HV_PCIE_GUID,
-	  .perf_device =3D true,
+	  .perf_device =3D false,
 	},
=20
 	/* Synthetic Frame Buffer */
--=20
2.7.4