On Sat, Feb 4, 2012 at 10:57 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> will use them insert/update busn res in pci_bus
>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> ---
> drivers/pci/probe.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/pci.h | 3 +++
> 2 files changed, 45 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index a114173..8d4de5e 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1622,6 +1622,48 @@ err_out:
> return NULL;
> }
>
> +void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
> +{
> + struct resource *res = &b->busn_res;
> + struct resource *parent_res = &iobusn_resource;
> + int ret;
> +
> + res->start = busn(pci_domain_nr(b), bus);
> + res->end = busn(pci_domain_nr(b), bus_max);
> + res->flags = IORESOURCE_BUS;
> +
> + if (!pci_is_root_bus(b))
> + parent_res = &b->parent->busn_res;
> +
> + ret = insert_resource(parent_res, res);
> +
> + dev_printk(KERN_DEBUG, &b->dev,
> + "busn_res: %pR %s inserted under %pR\n",
> + res, ret ? "can not be" : "is", parent_res);
> +}
> +
> +void pci_bus_update_busn_res_end(struct pci_bus *b, int bus_max)
> +{
> + struct resource *res = &b->busn_res;
> + struct resource old_res = *res;
> +
> + res->end = busn_update_bus_nr(res->end, bus_max);
I think this design is a mistake. Here's what you're doing:
- initialize struct resource (keys are "start" and "end")
- insert into tree (placed in tree by kernel/resource.c based on
"start" and "end")
- update "end"
You "know" in this case that the update is safe because the caller has
validated "bus_max." But that still breaks the kernel/resource.c
encapsulation. If we change the kernel/resource.c implementation,
this code might break.
I think it would be better to remove the bus resource from the tree,
change its "end," then re-insert it.
> + dev_printk(KERN_DEBUG, &b->dev,
> + "busn_res: %pR end updated to %pR\n",
> + &old_res, res);
> +}
> +
> +void pci_bus_release_busn_res(struct pci_bus *b)
> +{
> + struct resource *res = &b->busn_res;
> + int ret;
> +
> + ret = release_resource(res);
> + dev_printk(KERN_DEBUG, &b->dev,
> + "busn_res: %pR %s released\n",
> + res, ret ? "can not be" : "is");
> +}
> +
> struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
> struct pci_ops *ops, void *sysdata, struct list_head *resources)
> {
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 94ad468..3da935c 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -665,6 +665,9 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata);
> struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> struct pci_ops *ops, void *sysdata,
> struct list_head *resources);
> +void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax);
> +void pci_bus_update_busn_res_end(struct pci_bus *b, int busmax);
> +void pci_bus_release_busn_res(struct pci_bus *b);
> struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
> struct pci_ops *ops, void *sysdata,
> struct list_head *resources);
> --
> 1.7.7
>
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