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    SubjectRe: [RESEND PATCH v2 2/4] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources
    On Thu, Jun 02, 2016 at 01:46:49PM +0800, Yongji Xie wrote:
    > Now we use the IORESOURCE_STARTALIGN to identify bridge resources
    > in __assign_resources_sorted(). That's quite fragile. We can't
    > make sure that the PCI devices' resources will not use
    > IORESOURCE_STARTALIGN any more.

    Can you explain this a little more? I don't quite understand the
    problem. Maybe you can give an example of the problem?

    > In this patch, we try to use a more robust way to identify
    > bridge resources.
    >
    > Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
    > ---
    > drivers/pci/setup-bus.c | 9 ++++++---
    > 1 file changed, 6 insertions(+), 3 deletions(-)
    >
    > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
    > index 55641a3..216ddbc 100644
    > --- a/drivers/pci/setup-bus.c
    > +++ b/drivers/pci/setup-bus.c
    > @@ -390,6 +390,7 @@ static void __assign_resources_sorted(struct list_head *head,
    > struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
    > unsigned long fail_type;
    > resource_size_t add_align, align;
    > + int index;
    >
    > /* Check if optional add_size is there */
    > if (!realloc_head || list_empty(realloc_head))
    > @@ -410,11 +411,13 @@ static void __assign_resources_sorted(struct list_head *head,
    >
    > /*
    > * There are two kinds of additional resources in the list:
    > - * 1. bridge resource -- IORESOURCE_STARTALIGN
    > - * 2. SR-IOV resource -- IORESOURCE_SIZEALIGN
    > + * 1. bridge resource
    > + * 2. SR-IOV resource
    > * Here just fix the additional alignment for bridge
    > */
    > - if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
    > + index = dev_res->res - dev_res->dev->resource;
    > + if (index < PCI_BRIDGE_RESOURCES ||
    > + index > PCI_BRIDGE_RESOURCE_END)

    I think the code looks OK; at least, it seems to match the comment.
    I'd just like to understand the problem a little better.

    > continue;
    >
    > add_align = get_res_add_align(realloc_head, dev_res->res);
    > --
    > 1.7.9.5
    >

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