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SubjectRe: [RFC v5 2/7] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources
On Tue, Apr 05, 2016 at 09:43:30PM +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.
>
>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 | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>index 7796d0a..bffcf1e 100644
>--- a/drivers/pci/setup-bus.c
>+++ b/drivers/pci/setup-bus.c
>@@ -391,6 +391,7 @@ 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))
>@@ -411,11 +412,14 @@ 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 (pci_is_bridge(dev_res->dev) &&
>+ index >= PCI_BRIDGE_RESOURCES &&
>+ index <= PCI_BRIDGE_RESOURCE_END)
> continue;

Yongji, the condition seems incorrect. According to the comments in
the code, it's resizing bridge's windows. So I think the code would
be something like below?

if (!pci_is_bridge(dev_res->dev) ||
index < PCI_BRIDGE_RESOURCES ||
index > PCI_BRIDGE_RESOURCE_END)
continue;

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

Thanks,
Gavin

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