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Message-ID: <KL1P15301MB0006C96F94181FFB93A222D8BFD00@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM>
Date: Thu, 15 Mar 2018 14:20:53 +0000
From: Dexuan Cui <decui@...rosoft.com>
To: "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
KY Srinivasan <kys@...rosoft.com>,
Stephen Hemminger <sthemmin@...rosoft.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"driverdev-devel@...uxdriverproject.org"
<driverdev-devel@...uxdriverproject.org>,
Haiyang Zhang <haiyangz@...rosoft.com>,
"olaf@...fle.de" <olaf@...fle.de>,
"apw@...onical.com" <apw@...onical.com>,
"jasowang@...hat.com" <jasowang@...hat.com>,
"vkuznets@...hat.com" <vkuznets@...hat.com>,
"marcelo.cerri@...onical.com" <marcelo.cerri@...onical.com>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@...rosoft.com>
Subject: [PATCH v4 1/2] PCI: hv: Serialize the present and eject work items
When we hot-remove the device, we first receive a PCI_EJECT message and
then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0.
The first message is offloaded to hv_eject_device_work(), and the second
is offloaded to pci_devices_present_work(). Both the paths can be running
list_del(&hpdev->list_entry), causing general protection fault, because
system_wq can run them concurrently.
The patch eliminates the race condition.
Tested-by: Adrian Suhov <v-adsuho@...rosoft.com>
Tested-by: Chris Valean <v-chvale@...rosoft.com>
Signed-off-by: Dexuan Cui <decui@...rosoft.com>
Reviewed-by: Michael Kelley <mikelley@...rosoft.com>
Acked-by: Haiyang Zhang <haiyangz@...rosoft.com>
Cc: stable@...r.kernel.org
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Jack Morgenstein <jackm@...lanox.com>
Cc: Stephen Hemminger <sthemmin@...rosoft.com>
Cc: K. Y. Srinivasan <kys@...rosoft.com>
---
drivers/pci/host/pci-hyperv.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 2faf38eab785..5e67dff779a7 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -461,6 +461,8 @@ struct hv_pcibus_device {
struct retarget_msi_interrupt retarget_msi_interrupt_params;
spinlock_t retarget_msi_interrupt_lock;
+
+ struct workqueue_struct *wq;
};
/*
@@ -1770,7 +1772,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
spin_unlock_irqrestore(&hbus->device_list_lock, flags);
get_hvpcibus(hbus);
- schedule_work(&dr_wrk->wrk);
+ queue_work(hbus->wq, &dr_wrk->wrk);
}
/**
@@ -1848,7 +1850,7 @@ static void hv_pci_eject_device(struct hv_pci_dev *hpdev)
get_pcichild(hpdev, hv_pcidev_ref_pnp);
INIT_WORK(&hpdev->wrk, hv_eject_device_work);
get_hvpcibus(hpdev->hbus);
- schedule_work(&hpdev->wrk);
+ queue_work(hpdev->hbus->wq, &hpdev->wrk);
}
/**
@@ -2463,11 +2465,17 @@ static int hv_pci_probe(struct hv_device *hdev,
spin_lock_init(&hbus->retarget_msi_interrupt_lock);
sema_init(&hbus->enum_sem, 1);
init_completion(&hbus->remove_event);
+ hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,
+ hbus->sysdata.domain);
+ if (!hbus->wq) {
+ ret = -ENOMEM;
+ goto free_bus;
+ }
ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
hv_pci_onchannelcallback, hbus);
if (ret)
- goto free_bus;
+ goto destroy_wq;
hv_set_drvdata(hdev, hbus);
@@ -2536,6 +2544,8 @@ static int hv_pci_probe(struct hv_device *hdev,
hv_free_config_window(hbus);
close:
vmbus_close(hdev->channel);
+destroy_wq:
+ destroy_workqueue(hbus->wq);
free_bus:
free_page((unsigned long)hbus);
return ret;
@@ -2615,6 +2625,7 @@ static int hv_pci_remove(struct hv_device *hdev)
irq_domain_free_fwnode(hbus->sysdata.fwnode);
put_hvpcibus(hbus);
wait_for_completion(&hbus->remove_event);
+ destroy_workqueue(hbus->wq);
free_page((unsigned long)hbus);
return 0;
}
--
2.7.4
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