On Tue, Aug 19, 2014 at 09:08:41PM -0600, Bjorn Helgaas wrote:
>On Thu, Jul 24, 2014 at 02:22:14PM +0800, Wei Yang wrote:
>> At resource sizing/assigning stage, resources are divided into two lists,
>> requested list and additional list, while the alignement of the additional
>> IOV BAR is not taken into the sizeing and assigning procedure.
>>
>> This is reasonable in the original implementation, since IOV BAR's alignment is
>> mostly the size of a PF BAR alignemt. This means the alignment is already taken
>> into consideration. While this rule may be violated on some platform.
>>
>> This patch take the additional IOV BAR alignment in sizing and assigning stage
>> explicitly.
>>
>> Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/pci/setup-bus.c | 68 +++++++++++++++++++++++++++++++++++++++++------
>> 1 file changed, 60 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>> index a5a63ec..d83681f 100644
>> --- a/drivers/pci/setup-bus.c
>> +++ b/drivers/pci/setup-bus.c
>> @@ -120,6 +120,28 @@ static resource_size_t get_res_add_size(struct list_head *head,
>> return 0;
>> }
>>
>> +static resource_size_t get_res_add_align(struct list_head *head,
>> + struct resource *res)
>> +{
>> + struct pci_dev_resource *dev_res;
>> +
>> + list_for_each_entry(dev_res, head, list) {
>> + if (dev_res->res == res) {
>> + int idx = res - &dev_res->dev->resource[0];
>> +
>> + dev_printk(KERN_DEBUG, &dev_res->dev->dev,
>> + "res[%d]=%pR get_res_add_align min_align %llx\n",
>> + idx, dev_res->res,
>> + (unsigned long long)dev_res->min_align);
>> +
>> + return dev_res->min_align;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>
>I see that you copied the structure of the existing get_res_add_size()
>here. But I don't understand *that* function. It looks basically like
>this:
>
> resource_size_t get_res_add_size(list, res)
> {
> list_for_each_entry(dev_res, head, list) {
> if (dev_res->res == res)
> return dev_res->add_size;
> }
> return 0;
> }
>
>and we call it like this:
>
> dev_res->res->end += get_res_add_size(realloc_head, dev_res->res);
>
>So we start out with dev_res", pass in dev_res->res, search the
>realloc_head list to find dev_res again, and return dev_res->add_size.
>That looks equivalent to just:
>
> dev_res->res->end += dev_res->add_size;
>
>It looks like get_res_add_size() merely adds a printk and some complexity.
>Am I missing something?
>
Let me try to explain it, if not correct, please let know :-)
dev_res->res->end += get_res_add_size(realloc_head, dev_res->res);
would be expanded to:
dev_res->res->end += dev_res_1->add_size;
with the dev_res_1 is another one from dev_res which is stored in realloc_head.
>I do see that there are other callers where we don't actually start with
>dev_res, which makes it a little more complicated. But I think you should
>either add something like this:
>
> struct pci_dev_resource *res_to_dev_res(list, res)
> {
> list_for_each_entry(dev_res, head, list) {
> if (dev_res->res == res)
> return dev_res;
> }
> return NULL;
> }
>
Ok, we can extract the common part of these two functions.
>which can be used to replace get_res_add_size() and get_res_add_align(), OR
>figure out whether the dev_res of interest is always one we've just added.
>If it is, maybe you can just make add_to_list() return the dev_res pointer
>instead of an errno, and hang onto the pointer. I'd like that much better
>if that's possible.
>
Sorry, I don't get this point.
add_to_list() is used to create the pci_dev_resource list, get_res_add_size()
and get_res_add_align() is to retrieve the information in the list. I am not
sure how to leverage add_to_list() in these two functions?
>> +
>> +
>> /* Sort resources by alignment */
>> static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
>> {
>> @@ -368,8 +390,9 @@ static void __assign_resources_sorted(struct list_head *head,
>> LIST_HEAD(save_head);
>> LIST_HEAD(local_fail_head);
>> struct pci_dev_resource *save_res;
>> - struct pci_dev_resource *dev_res, *tmp_res;
>> + struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
>> unsigned long fail_type;
>> + resource_size_t add_align, align;
>>
>> /* Check if optional add_size is there */
>> if (!realloc_head || list_empty(realloc_head))
>> @@ -384,10 +407,31 @@ static void __assign_resources_sorted(struct list_head *head,
>> }
>>
>> /* Update res in head list with add_size in realloc_head list */
>> - list_for_each_entry(dev_res, head, list)
>> + list_for_each_entry_safe(dev_res, tmp_res, head, list) {
>> dev_res->res->end += get_res_add_size(realloc_head,
>> dev_res->res);
>>
>> + if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
>> + continue;
>> +
>> + add_align = get_res_add_align(realloc_head, dev_res->res);
>> +
>> + if (add_align > dev_res->res->start) {
>> + dev_res->res->start = add_align;
>> + dev_res->res->end = add_align +
>> + resource_size(dev_res->res);
>> +
>> + list_for_each_entry(dev_res2, head, list) {
>> + align = pci_resource_alignment(dev_res2->dev,
>> + dev_res2->res);
>> + if (add_align > align)
>> + list_move_tail(&dev_res->list,
>> + &dev_res2->list);
>> + }
>> + }
>> +
>> + }
>> +
>> /* Try updated head list with add_size added */
>> assign_requested_resources_sorted(head, &local_fail_head);
>>
>> @@ -930,6 +974,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>> struct resource *b_res = find_free_bus_resource(bus,
>> mask | IORESOURCE_PREFETCH, type);
>> resource_size_t children_add_size = 0;
>> + resource_size_t children_add_align = 0;
>> + resource_size_t add_align = 0;
>>
>> if (!b_res)
>> return -ENOSPC;
>> @@ -954,6 +1000,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>> /* put SRIOV requested res to the optional list */
>> if (realloc_head && i >= PCI_IOV_RESOURCES &&
>> i <= PCI_IOV_RESOURCE_END) {
>> + add_align = max(pci_resource_alignment(dev, r), add_align);
>> r->end = r->start - 1;
>> add_to_list(realloc_head, dev, r, r_size, 0/* don't care */);
>> children_add_size += r_size;
>> @@ -984,8 +1031,11 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>> if (order > max_order)
>> max_order = order;
>>
>> - if (realloc_head)
>> + if (realloc_head) {
>> children_add_size += get_res_add_size(realloc_head, r);
>> + children_add_align = get_res_add_align(realloc_head, r);
>> + add_align = max(add_align, children_add_align);
>> + }
>> }
>> }
>>
>> @@ -996,7 +1046,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>> add_size = children_add_size;
>> size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
>> calculate_memsize(size, min_size, add_size,
>> - resource_size(b_res), min_align);
>> + resource_size(b_res), max(min_align, add_align));
>> if (!size0 && !size1) {
>> if (b_res->start || b_res->end)
>> dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n",
>> @@ -1008,10 +1058,12 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>> b_res->end = size0 + min_align - 1;
>> b_res->flags |= IORESOURCE_STARTALIGN;
>> if (size1 > size0 && realloc_head) {
>> - add_to_list(realloc_head, bus->self, b_res, size1-size0, min_align);
>> - dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx\n",
>> - b_res, &bus->busn_res,
>> - (unsigned long long)size1-size0);
>> + add_to_list(realloc_head, bus->self, b_res, size1-size0,
>> + max(min_align, add_align));
>> + dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window "
>> + "%pR to %pR add_size %llx add_align %llx\n", b_res,
>> + &bus->busn_res, (unsigned long long)size1-size0,
>> + max(min_align, add_align));
>
>Factor out this "max(min_align, add_align)" thing so we don't have to
>change these lines. Bonus points if you can also factor it out of the
>calculate_memsize() call above. That one is a pretty complicated ternary
>expression that should probably be turned into an "if" instead anyway.
>
Ok, I get your point. Let me make it more easy to read.
>> }
>> return 0;
>> }
>> --
>> 1.7.9.5
>>
--
Richard Yang
Help you, Help me
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