RE: [E1000-devel] [PATCH 0/2] Remove dead code

From: Brown, Aaron F
Date: Fri Jan 31 2014 - 14:20:41 EST


> From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx]
> Sent: Friday, January 31, 2014 9:59 AM
> To: Brown, Aaron F
> Cc: linux-pci@xxxxxxxxxxxxxxx; e1000-devel@xxxxxxxxxxxxxxxxxxxxx; Arjan
> van de Ven; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [E1000-devel] [PATCH 0/2] Remove dead code
>
> On Fri, Jan 31, 2014 at 2:10 AM, Brown, Aaron F <aaron.f.brown@xxxxxxxxx>
> wrote:
> >> From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx]
> >> Sent: Thursday, January 30, 2014 11:21 AM
> >> To: linux-pci@xxxxxxxxxxxxxxx
> >> Cc: e1000-devel@xxxxxxxxxxxxxxxxxxxxx; Arjan van de Ven; linux-
> >> kernel@xxxxxxxxxxxxxxx
> >> Subject: [E1000-devel] [PATCH 0/2] Remove dead code
> >>
> >> This is a rework of part of Stephen's patch [1].
> >>
> >> This removes the MMIO exclusivity support that was added as part of
> >> an e1000e bug hunt.
> >>
> >> The e1000e driver still uses
> >> pci_request_selected_regions_exclusive(), but there are no callers of
> >> pci_request_region_exclusive() and pci_request_regions_exclusive().
> >> I thought it was cleaner to remove the whole thing than to leave
> >> parts of it in place. But I could easily be convinced to leave part
> >> or all of this in place if people think it's still useful.
> >
> > Thanks Bjorn, I have added these to Jeff's queue.
>
> Let's wait for a bit more discussion on this.
>
> For one thing, Fengguang's autobuilder found a handful of issues,
> including a couple more users of the exclusive mappings. For another,
> Arjan reminded me that the e1000e bug hung was for a problem that bricked
> the device, requiring replacement of the part or significant effort to fix
> the EEPROM. I *suspect* this is a potential issue for many devices, but
> if the e1000e is particularly susceptible for some reason, we might want
> to keep the exclusive mappings for it.
>
> If you want to apply just the e1000e part that removes its use of
> pci_request_selected_regions_exclusive(), I would have no complaints about
> that, of course.

Yes, that was my main intent. I did pull them both in but the second was more as a heads up to our virtualization guys then as a request to test.

> But we can't apply the whole thing as-is without at
> least fixing the build issues.

Thanks for the heads up on that. I'll sort out something that builds with the e1000e parts removed on my end.

>
> >> It also removes SR-IOV migration support, which is completely unused,
> >> as far as I can tell.
> >>
> >> [1]
> >> http://lkml.kernel.org/r/20131227132710.7190647c@xxxxxxxxxxxxxxxxxxxx
> >> ber.n
> >> et
> >>
> >> ---
> >>
> >> Bjorn Helgaas (2):
> >> PCI: Remove unused MMIO exclusivity support
> >> PCI: Remove unused SR-IOV VF Migration support
> >>
> >>
> >> Documentation/PCI/pci-iov-howto.txt | 4 -
> >> Documentation/kernel-parameters.txt | 4 -
> >> arch/x86/mm/init.c | 2
> >> drivers/net/ethernet/intel/e1000e/netdev.c | 3 -
> >> drivers/pci/iov.c | 119 --------------------
> ---
> >> -----
> >> drivers/pci/pci-sysfs.c | 3 -
> >> drivers/pci/pci.c | 112 +++-----------------
> ---
> >> ---
> >> drivers/pci/pci.h | 4 -
> >> include/linux/ioport.h | 5 -
> >> include/linux/pci.h | 7 --
> >> kernel/resource.c | 54 -------------
> >> 11 files changed, 14 insertions(+), 303 deletions(-)
> >>
> >> ---------------------------------------------------------------------
> >> -----
> >> ----
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> >> rk
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> >> E1000-devel@xxxxxxxxxxxxxxxxxxxxx
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