[PATCH 4.9 082/153] PCI: hv: Fix wslot_to_devfn() to fix warnings on device removal

Greg Kroah-Hartman
2017-03-10T11:16:05Z

From: Dexuan Cui <decui@microsoft.com>

commit 60e2e2fbafdd1285ae1b4ad39ded41603e0c74d0 upstream.

The devfn of 00:02.0 is 0x10. devfn_to_wslot(0x10) == 0x2, and
wslot_to_devfn(0x2) should be 0x10, while it's 0x2 in the current code.

Due to this, hv_eject_device_work() -> pci_get_domain_bus_and_slot()
returns NULL and pci_stop_and_remove_bus_device() is not called.

Later when the real device driver's .remove() is invoked by
hv_pci_remove() -> pci_stop_root_bus(), some warnings can be noticed
because the VM has lost the access to the underlying device at that
time.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
CC: K. Y. Srinivasan <kys@microsoft.com>
CC: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/host/pci-hyperv.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -130,7 +130,8 @@ union pci_version {
*/
union win_slot_encoding {
struct {
- u32 func:8;
+ u32 dev:5;
+ u32 func:3;
u32 reserved:24;
} bits;
u32 slot;
@@ -483,7 +484,8 @@ static u32 devfn_to_wslot(int devfn)
union win_slot_encoding wslot;

wslot.slot = 0;
- wslot.bits.func = PCI_SLOT(devfn) | (PCI_FUNC(devfn) << 5);
+ wslot.bits.dev = PCI_SLOT(devfn);
+ wslot.bits.func = PCI_FUNC(devfn);

return wslot.slot;
}
@@ -501,7 +503,7 @@ static int wslot_to_devfn(u32 wslot)
union win_slot_encoding slot_no;

slot_no.slot = wslot;
- return PCI_DEVFN(0, slot_no.bits.func);
+ return PCI_DEVFN(slot_no.bits.dev, slot_no.bits.func);
}

/*