On 2016/6/21 9:50, Bjorn Helgaas wrote:
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?
Now there are two kinds of additional resources in the list: bridge
resource and SR-IOV resource. Here we just want to fix the
additional alignment for bridge. But if SR-IOV resource get the
flag IORESOURCE_STARTALIGN which is not only for bridge, the
current check seems to be wrong. And kernel parameter
"resource_alignment" could set IORESOURCE_STARTALIGN for
SR-IOV resource with my next patch applied.
Thanks,
Yongji
In this patch, we try to use a more robust way to identify
bridge resources.
Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
---
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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