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[RFC,v5,2/7] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources

Message ID 1459863813-2830-3-git-send-email-xyjxie@linux.vnet.ibm.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Yongji Xie April 5, 2016, 1:43 p.m. UTC
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(-)

Comments

Gavin Shan April 6, 2016, 12:55 a.m. UTC | #1
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
Yongji Xie April 6, 2016, 2:16 a.m. UTC | #2
On 2016/4/6 8:55, Gavin Shan wrote:
> 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;

Yes. I made a mistake here. It should be something like
the above code.

Thanks,
Yongji

>> 		add_align = get_res_add_align(realloc_head, dev_res->res);
> Thanks,
> Gavin
>
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diff mbox

Patch

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