Re: [PATCH] PCI: pci-hyperv: fix build errors on non-SYSFS config

[Bjorn Helgaas <helgaas@kernel.org>]

On Sat, Jul 13, 2019 at 11:03:53AM -0400, Sasha Levin wrote:
> On Fri, Jul 12, 2019 at 04:04:17PM +0000, Haiyang Zhang wrote:
> > > -----Original Message-----
> > > From: Randy Dunlap <rdunlap@infradead.org>
> > > Sent: Friday, July 12, 2019 11:53 AM
> > > To: linux-pci <linux-pci@vger.kernel.org>; LKML <linux-
> > > kernel@vger.kernel.org>
> > > Cc: Matthew Wilcox <willy@infradead.org>; Jake Oshins
> > > <jakeo@microsoft.com>; KY Srinivasan <kys@microsoft.com>; Haiyang
> > > Zhang <haiyangz@microsoft.com>; Stephen Hemminger
> > > <sthemmin@microsoft.com>; Stephen Hemminger
> > > <stephen@networkplumber.org>; Sasha Levin <sashal@kernel.org>; Bjorn
> > > Helgaas <bhelgaas@google.com>; Dexuan Cui <decui@microsoft.com>
> > > Subject: [PATCH] PCI: pci-hyperv: fix build errors on non-SYSFS config

Whoever merges this (see below), please update the subject line to
match:

  $ git log --oneline drivers/pci/controller/pci-hyperv.c | head -5
  4df591b20b80 PCI: hv: Fix a use-after-free bug in hv_eject_device_work()
  340d45569940 PCI: hv: Add pci_destroy_slot() in pci_devices_present_work(), if necessary
  15becc2b56c6 PCI: hv: Add hv_pci_remove_slots() when we unload the driver
  05f151a73ec2 PCI: hv: Fix a memory leak in hv_eject_device_work()
  c8ccf7599dda PCI: hv: Refactor hv_irq_unmask() to use cpumask_to_vpset()

> > > From: Randy Dunlap <rdunlap@infradead.org>
> > > 
> > > Fix build errors when building almost-allmodconfig but with SYSFS
> > > not set (not enabled).  Fixes these build errors:
> > > 
> > > ERROR: "pci_destroy_slot" [drivers/pci/controller/pci-hyperv.ko] undefined!
> > > ERROR: "pci_create_slot" [drivers/pci/controller/pci-hyperv.ko] undefined!
> > > 
> > > drivers/pci/slot.o is only built when SYSFS is enabled, so
> > > pci-hyperv.o has an implicit dependency on SYSFS.
> > > Make that explicit.
> > > 
> > > Also, depending on X86 && X86_64 is not needed, so just change that
> > > to depend on X86_64.
> > > 
> > > Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot
> > > information")
> > > 
> > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > Cc: Matthew Wilcox <willy@infradead.org>
> > > Cc: Jake Oshins <jakeo@microsoft.com>
> > > Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> > > Cc: Haiyang Zhang <haiyangz@microsoft.com>
> > > Cc: Stephen Hemminger <sthemmin@microsoft.com>
> > > Cc: Stephen Hemminger <stephen@networkplumber.org>
> > > Cc: Sasha Levin <sashal@kernel.org>
> > > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > > Cc: linux-pci@vger.kernel.org
> > > Cc: linux-hyperv@vger.kernel.org
> > > Cc: Dexuan Cui <decui@microsoft.com>
> > > ---
> > > v3: corrected Fixes: tag [Dexuan Cui <decui@microsoft.com>]
> > >     This is the Microsoft-preferred version of the patch.
> > > 
> > >  drivers/pci/Kconfig |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > --- lnx-52.orig/drivers/pci/Kconfig
> > > +++ lnx-52/drivers/pci/Kconfig
> > > @@ -181,7 +181,7 @@ config PCI_LABEL
> > > 
> > >  config PCI_HYPERV
> > >          tristate "Hyper-V PCI Frontend"
> > > -        depends on X86 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN
> > > && X86_64
> > > +        depends on X86_64 && HYPERV && PCI_MSI &&
> > > PCI_MSI_IRQ_DOMAIN && SYSFS
> > >          help
> > >            The PCI device frontend driver allows the kernel to import arbitrary
> > >            PCI devices from a PCI backend to support PCI driver domains.
> > > 
> > 
> > Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
> 
> Queued up for hyperv-fixes, thank you!

What merge strategy do you envision for this?  Previous
drivers/pci/controller/pci-hyperv.c changes have generally been merged
by Lorenzo and incorporated into my PCI tree.

This particular patch doesn't actually touch pci-hyperv.c; it touches
drivers/pci/Kconfig, so should somehow be coordinated with me.

Does this need to be tagged for stable?  a15f2c08c708 appeared in
v4.19, so my first guess is that it's not stable material.

Bjorn