RE: [PATCH 4.18 101/135] hv_netvsc: pair VF based on serial number

Haiyang Zhang
2018-10-17T13:02:26Z

> -----Original Message-----
> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Sent: Wednesday, October 17, 2018 3:46 AM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: linux-kernel@vger.kernel.org; stable@vger.kernel.org; Stephen Hemminger
> <sthemmin@microsoft.com>; David S. Miller <davem@davemloft.net>; Sasha
> Levin <Alexander.Levin@microsoft.com>
> Subject: Re: [PATCH 4.18 101/135] hv_netvsc: pair VF based on serial number
>
> On Tue, Oct 16, 2018 at 07:13:12PM +0000, Haiyang Zhang wrote:
> >
> >
> > > -----Original Message-----
> > > From: linux-kernel-owner@vger.kernel.org <linux-kernel-
> > > owner@vger.kernel.org> On Behalf Of Greg Kroah-Hartman
> > > Sent: Tuesday, October 16, 2018 1:06 PM
> > > To: linux-kernel@vger.kernel.org
> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>;
> > > stable@vger.kernel.org; Stephen Hemminger <sthemmin@microsoft.com>;
> > > David S. Miller <davem@davemloft.net>; Sasha Levin
> > > <Alexander.Levin@microsoft.com>
> > > Subject: [PATCH 4.18 101/135] hv_netvsc: pair VF based on serial
> > > number
> > >
> > > 4.18-stable review patch. If anyone has any objections, please let me know.
> > >
> > > ------------------
> > >
> > > From: Stephen Hemminger <stephen@networkplumber.org>
> > >
> > > [ Upstream commit 00d7ddba1143623b31bc2c15d18216e2da031b14 ]
> > >
> > > Matching network device based on MAC address is problematic since a
> > > non VF network device can be creted with a duplicate MAC address
> > > causing confusion and problems. The VMBus API does provide a serial
> > > number that is a better matching method.
> > >
> > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
> > > Signed-off-by: David S. Miller <davem@davemloft.net>
> > > Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > ---
> > > drivers/net/hyperv/netvsc.c | 3 ++
> > > drivers/net/hyperv/netvsc_drv.c | 58 ++++++++++++++++++++++------------
> -----
> > > -
> > > 2 files changed, 36 insertions(+), 25 deletions(-)
> > >
> > > --- a/drivers/net/hyperv/netvsc.c
> > > +++ b/drivers/net/hyperv/netvsc.c
> > > @@ -1203,6 +1203,9 @@ static void netvsc_send_vf(struct net_de
> > >
> > > net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
> > > net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
> > > + netdev_info(ndev, "VF slot %u %s\n",
> > > + net_device_ctx->vf_serial,
> > > + net_device_ctx->vf_alloc ? "added" : "removed");
> > > }
> > >
> > > static void netvsc_receive_inband(struct net_device *ndev,
> > > --- a/drivers/net/hyperv/netvsc_drv.c
> > > +++ b/drivers/net/hyperv/netvsc_drv.c
> > > @@ -1794,20 +1794,6 @@ out_unlock:
> > > rtnl_unlock();
> > > }
> > >
> > > -static struct net_device *get_netvsc_bymac(const u8 *mac) -{
> > > - struct net_device_context *ndev_ctx;
> > > -
> > > - list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
> > > - struct net_device *dev = hv_get_drvdata(ndev_ctx-
> > > >device_ctx);
> > > -
> > > - if (ether_addr_equal(mac, dev->perm_addr))
> > > - return dev;
> > > - }
> > > -
> > > - return NULL;
> > > -}
> > > -
> > > static struct net_device *get_netvsc_byref(struct net_device *vf_netdev) {
> > > struct net_device_context *net_device_ctx; @@ -1936,26 +1922,48
> @@
> > > static void netvsc_vf_setup(struct work_
> > > rtnl_unlock();
> > > }
> > >
> > > +/* Find netvsc by VMBus serial number.
> > > + * The PCI hyperv controller records the serial number as the slot.
> > > + */
> > > +static struct net_device *get_netvsc_byslot(const struct net_device
> > > +*vf_netdev) {
> > > + struct device *parent = vf_netdev->dev.parent;
> > > + struct net_device_context *ndev_ctx;
> > > + struct pci_dev *pdev;
> > > +
> > > + if (!parent || !dev_is_pci(parent))
> > > + return NULL; /* not a PCI device */
> > > +
> > > + pdev = to_pci_dev(parent);
> > > + if (!pdev->slot) {
> > > + netdev_notice(vf_netdev, "no PCI slot information\n");
> > > + return NULL;
> > > + }
> > > +
> > > + list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
> > > + if (!ndev_ctx->vf_alloc)
> > > + continue;
> > > +
> > > + if (ndev_ctx->vf_serial == pdev->slot->number)
> > > + return hv_get_drvdata(ndev_ctx->device_ctx);
> >
> > Greg,
> >
> > I had a fix to this patch. If not already, Could you include my following fix
> together?
> > hv_netvsc: fix vf serial matching with pci slot info
> > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.k
> > ernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fdavem%2Fnet-
> next.git%2F
> >
> commit%2F%3Fid%3D005479556197f80139771960dda0dfdcd2d2aad5&amp;da
> ta=02%
> >
> 7C01%7Chaiyangz%40microsoft.com%7C6ce194a47449435fe82a08d63404a94e
> %7C7
> >
> 2f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636753591959679786&amp
> ;sdata
> >
> =ReWYMZW%2FYtoFSbFSxny9VGw6V8v9J4sGanfJjbVd34A%3D&amp;reserved=
> 0
>
> I can not take a patch that is not "upstream" yet, sorry.
>
> Also, this really feels like a "new feature" to me. Can someone explain what
> bug this is fixing?

Patch #A: hv_netvsc: pair VF based on serial number
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=00d7ddba1143623b31bc2c15d18216e2da031b14

Patch #B: hv_netvsc: fix vf serial matching with pci slot info
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=005479556197f80139771960dda0dfdcd2d2aad5

The patch #A is a feature that use VF serial number for matching. But #A has a bug causing mismatch.

Patch #B, upstream now (see the link to Linux-next), is a fix to #A.

So, if #A is ported to 4.18, we need to port #B together. Otherwise, not porting both the #A and #B is also fine.

Thanks,
- Haiyang