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From:   Dexuan Cui <decui@microsoft.com>
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        "bhelgaas@google.com" <bhelgaas@google.com>,
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        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
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CC:     "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
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Subject: [PATCH 2/3] PCI: hv: Add hv_pci_remove_slots() when we unload the
 driver
Thread-Topic: [PATCH 2/3] PCI: hv: Add hv_pci_remove_slots() when we unload
 the driver
Thread-Index: AQHU0tIYYM00GlnBAUeAnbzMfj5zdw==
Date:   Mon, 4 Mar 2019 21:34:48 +0000
Message-ID: <20190304213357.16652-3-decui@microsoft.com>
References: <20190304213357.16652-1-decui@microsoft.com>
In-Reply-To: <20190304213357.16652-1-decui@microsoft.com>
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When we unload pci-hyperv, the host doesn't send us a PCI_EJECT message.
In this case we also need to make sure the sysfs pci slot directory
is removed, otherwise "cat /sys/bus/pci/slots/2/address" will trigger
"BUG: unable to handle kernel paging request" (I noticed the issue when
systemd-dev crashed for me when I unloaded the driver). And, if we
unload/reload the driver several times, we'll have multiple pci slot
directories in /sys/bus/pci/slots/ like this:

root@localhost:~# ls -rtl  /sys/bus/pci/slots/
total 0
drwxr-xr-x 2 root root 0 Feb  7 10:49 2
drwxr-xr-x 2 root root 0 Feb  7 10:49 2-1
drwxr-xr-x 2 root root 0 Feb  7 10:51 2-2

The patch adds the missing code.

Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot info=
rmation")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Acked-by: Stephen Hemminger <sthemmin@microsoft.com>
Cc: stable@vger.kernel.org
---
 drivers/pci/controller/pci-hyperv.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/p=
ci-hyperv.c
index 30f16b882746..b489412e3502 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1486,6 +1486,21 @@ static void hv_pci_assign_slots(struct hv_pcibus_dev=
ice *hbus)
 	}
 }
=20
+/*
+ * Remove entries in sysfs pci slot directory.
+ */
+static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
+{
+	struct hv_pci_dev *hpdev;
+
+	list_for_each_entry(hpdev, &hbus->children, list_entry) {
+		if (!hpdev->pci_slot)
+			continue;
+		pci_destroy_slot(hpdev->pci_slot);
+		hpdev->pci_slot =3D NULL;
+	}
+}
+
 /**
  * create_root_hv_pci_bus() - Expose a new root PCI bus
  * @hbus:	Root PCI bus, as understood by this driver
@@ -2680,6 +2695,7 @@ static int hv_pci_remove(struct hv_device *hdev)
 		pci_lock_rescan_remove();
 		pci_stop_root_bus(hbus->pci_bus);
 		pci_remove_root_bus(hbus->pci_bus);
+		hv_pci_remove_slots(hbus);
 		pci_unlock_rescan_remove();
 		hbus->state =3D hv_pcibus_removed;
 	}
--=20
2.19.1