linux-kernel - Re: [PATCH 12/13] PCI: kill pci_fixup_parent_subordinate

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Message-ID: <CAErSpo6JuJ-2u4KptUyx0N623f5X29CiqkzWEFTKnSFKQ6sP_w@mail.gmail.com>
Date:	Mon, 30 Jan 2012 08:09:19 -0800
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Tony Luck <tony.luck@...el.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org
Subject: Re: [PATCH 12/13] PCI: kill pci_fixup_parent_subordinate_busnr()

On Fri, Jan 27, 2012 at 6:49 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> Now we can safely extend parent top and shrink them according iobusn_resource tree.
>
> Don't need that any more.
>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
>  drivers/pci/probe.c |   45 +++++++++------------------------------------
>  1 files changed, 9 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 23c2f0d..54615a9 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -608,22 +608,6 @@ struct pci_bus *__ref pci_add_new_bus(struct pci_bus *parent, struct pci_dev *de
>        return child;
>  }
>
> -static void pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
> -{
> -       struct pci_bus *parent = child->parent;
> -
> -       /* Attempts to fix that up are really dangerous unless
> -          we're going to re-assign all bus numbers. */
> -       if (!pcibios_assign_all_busses())
> -               return;
> -
> -       while (parent->parent && parent->subordinate < max) {
> -               parent->subordinate = max;
> -               pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
> -               parent = parent->parent;
> -       }
> -}
> -
>  static void __devinit pci_bus_extend_top(struct pci_bus *parent,
>                 resource_size_t size, struct resource *parent_res)
>  {
> @@ -925,6 +909,13 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
>                /* Clear errors */
>                pci_write_config_word(dev, PCI_STATUS, 0xffff);
>
> +               /*
> +                * For CardBus bridges, we leave 4 bus numbers
> +                * as cards with a PCI-to-PCI bridge can be
> +                * inserted later.
> +                * other just allocate 8 bus to avoid we fall into
> +                *  small hole in the middle.
> +                */

This comment addition is in the wrong patch; it should go in the one
that added the code.

>                ret = pci_bridge_probe_busn_res(bus, dev, &busn_res,
>                                is_cardbus ? (CARDBUS_RESERVE_BUSNR + 1) : 8,
>                                &parent_res);
> @@ -963,29 +954,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
>
>                if (!is_cardbus) {
>                        child->bridge_ctl = bctl;
> -                       /*
> -                        * Adjust subordinate busnr in parent buses.
> -                        * We do this before scanning for children because
> -                        * some devices may not be detected if the bios
> -                        * was lazy.
> -                        */
> -                       pci_fixup_parent_subordinate_busnr(child, max);
> +
>                        /* Now we can scan all subordinate buses... */
>                        max = pci_scan_child_bus(child);
> -                       /*
> -                        * now fix it up again since we have found
> -                        * the real value of max.
> -                        */
> -                       pci_fixup_parent_subordinate_busnr(child, max);
> -
> -               } else {
> -                       /*
> -                        * For CardBus bridges, we leave 4 bus numbers
> -                        * as cards with a PCI-to-PCI bridge can be
> -                        * inserted later.
> -                        */
> -                       pci_fixup_parent_subordinate_busnr(child, max);
>                }
> +
>                /*
>                 * Set the subordinate bus number to its real value.
>                 */
> --
> 1.7.7
>
--
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