On Fri, Jul 19, 2013 at 1:14 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> After commit dc087f2f6a2925e81831f3016b9cbb6e470e7423
> (PCI: Simplify IOV implementation and fix reference count races)
> VF need to be removed via virtfn_remove to make sure ref to PF
> is put back.
>
> Some driver (like ixgbe) does not call pci_disable_sriov() if
> sriov is enabled via /sys/.../sriov_numvfs setting.
> ixgbe does allow driver for PF get detached, but still have VFs
> around.
>
> But how about PF get removed via /sys or pciehp?
>
> During hot-remove, VF will still hold one ref to PF and it
> prevent PF to be removed.
> That make the next hot-add fails, as old PF dev struct is still around.
>
> We need to add pci_disable_sriov() calling during pci dev removing.
>
> Need this one for v3.11
Needs explanation. Pretend Linus is asking why we should put this in
after the merge window :)
I think the answer is that dc087f2f introduced a regression in certain
hot-remove/hot-add scenarios, but an example transcript showing the
issue would help a lot.
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> Cc: Jiang Liu <liuj97@xxxxxxxxx>
> Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> Cc: Donald Dutile <ddutile@xxxxxxxxxx>
> Cc: Greg Rose <gregory.v.rose@xxxxxxxxx>
>
> ---
> drivers/pci/remove.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> Index: linux-2.6/drivers/pci/remove.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/remove.c
> +++ linux-2.6/drivers/pci/remove.c
> @@ -34,6 +34,9 @@ static void pci_stop_dev(struct pci_dev
>
> static void pci_destroy_dev(struct pci_dev *dev)
> {
> + /* remove VF, if PF driver skip that */
> + pci_disable_sriov(dev);
How did you decide to call pci_disable_sriov() here rather than, for
example, in pci_stop_dev()? We already have some PME and ASPM cleanup
in pci_stop_dev(), and this seems sort of similar to those.
> down_write(&pci_bus_sem);
> list_del(&dev->bus_list);
> up_write(&pci_bus_sem);
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