Linus Torvalds wrote:
>
> On Fri, 18 Dec 2009, Yinghai Lu wrote:
>> ok, please check attached is right or not
>>
>> +static void __release_child_resources(struct resource *r)
>> +{
>> + struct resource *tmp, *p;
>> + resource_size_t size;
>> +
>> + p = r->child;
>> + r->child = NULL;
>> + while (p) {
>> + tmp = p;
>> + p = p->sibling;
>> +
>> + tmp->parent = NULL;
>> + tmp->sibling = NULL;
>> + __release_child_resources(tmp);
>> +
>> + printk(KERN_DEBUG "release child resource %pR\n", tmp);
>> + /* need to restore size, and keep flags */
>> + size = resource_size(tmp);
>> + tmp->start = 0;
>> + tmp->end = size - 1;
>> + }
>> +}
>
> Ok, this looks mostly right. I do worry about the alignment information:
> you lose that thing for any resource that had IORESOURCE_STARTALIGN set
> when you do this thing. That's pretty fundamental to the whole resource
> code, I suspect we should just finally add a 'alignment' field to the
> resource struct, so that alignment doesn't get lost when a resource is
> allocated.
>
> (Do a "git grep IORESOURCE_.*ALIGN" to see the kind of stuff I'm talking
> about, and look at he PCI 'setup-bus.c' code that sets that STARTALIGN
> thing).
>
> So a preliminary ack on the resource.c parts. The rest I'm still a bit
> dubious about, and the whole "we've lost alignment on the resources" is
> probably indicative of how none of the resource code has ever really been
> designed for this kind of "tear down and build back up again" behavior.
arch/powerpc/kernel/pci_of_scan.c: flags |= IORESOURCE_SIZEALIGN;
drivers/pci/probe.c: res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
drivers/pci/probe.c: IORESOURCE_SIZEALIGN;
drivers/pci/setup-bus.c: b_res->flags |= IORESOURCE_STARTALIGN;
drivers/pci/setup-bus.c: b_res->flags |= IORESOURCE_STARTALIGN;
drivers/pci/setup-bus.c: b_res[0].flags |= IORESOURCE_IO | IORESOURCE_SIZEALIGN;
drivers/pci/setup-bus.c: b_res[1].flags |= IORESOURCE_IO | IORESOURCE_SIZEALIGN;
drivers/pci/setup-bus.c: b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH | IORESOURCE_SIZEALIGN;
drivers/pci/setup-bus.c: b_res[3].flags |= IORESOURCE_MEM | IORESOURCE_SIZEALIGN;
drivers/pci/setup-bus.c: b_res[3].flags |= IORESOURCE_MEM | IORESOURCE_SIZEALIGN;
drivers/pci/setup-res.c: res->flags &= ~IORESOURCE_STARTALIGN;
drivers/staging/b3dfg/b3dfg.c: != (IORESOURCE_MEM | IORESOURCE_SIZEALIGN)) {
include/linux/ioport.h:#define IORESOURCE_SIZEALIGN 0x00020000 /* size indicates alignment */
include/linux/ioport.h:#define IORESOURCE_STARTALIGN 0x00040000 /* start field is alignment */
kernel/resource.c: switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
kernel/resource.c: case IORESOURCE_SIZEALIGN:
kernel/resource.c: case IORESOURCE_STARTALIGN:
looks like IORESOURCE_SIZEALIGN is only used by bridge.
and next round. pbus_size_mem will add that back again.
YH
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