Re: [PATCH v8 10/30] PCI: Introduce pci_host_bridge_list to manage host bridges

Yijing Wang
2015-03-26T01:34:25Z

On 2015/3/26 0:42, Tomasz Nowicki wrote:
> On 24.03.2015 04:34, Yijing Wang wrote:
>> Introduce pci_host_bridge_list to manage pci host
>> bridges in system, this make us have the ability
>> to check whether the new host would conflict with
>> existing one. Then we could remove bus alreay exist
>> check in __pci_create_root_bus().
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> ---
>> drivers/pci/host-bridge.c | 41 ++++++++++++++++++++++++++++++++++++++++-
>> drivers/pci/probe.c | 9 +--------
>> include/linux/pci.h | 1 +
>> 3 files changed, 42 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
>> index 1a9834b..8af6d51 100644
>> --- a/drivers/pci/host-bridge.c
>> +++ b/drivers/pci/host-bridge.c
>> @@ -8,6 +8,9 @@
>>
>> #include "pci.h"
>>
>> +static LIST_HEAD(pci_host_bridge_list);
>> +static DEFINE_MUTEX(pci_host_mutex);
>> +
>> static void pci_release_host_bridge_dev(struct device *dev)
>> {
>> struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
>> @@ -41,12 +44,29 @@ static void pci_host_update_busn_res(
>> pci_add_resource(resources, &host->busn_res);
>> }
>>
>> +static bool pci_host_busn_res_overlap(
>> + struct pci_host_bridge *new, struct pci_host_bridge *old)
>> +{
>> + struct resource_entry *entry;
>> + struct resource *res1 = NULL, *res2 = NULL;
>> +
>> + resource_list_for_each_entry(entry, &old->windows)
>> + if (entry->res->flags & IORESOURCE_BUS)
>> + res1 = entry->res;
>> +
>> + resource_list_for_each_entry(entry, &new->windows)
>> + if (entry->res->flags & IORESOURCE_BUS)
>> + res2 = entry->res;
>> +
>> + return resource_overlaps(res1, res2);
>> +}
>> +
>> struct pci_host_bridge *pci_create_host_bridge(
>> struct device *parent, int domain, int bus,
>> struct list_head *resources)
>> {
>> int error;
>> - struct pci_host_bridge *host;
>> + struct pci_host_bridge *host, *tmp;
>> struct resource_entry *window, *n;
>>
>> host = kzalloc(sizeof(*host), GFP_KERNEL);
>> @@ -65,6 +85,21 @@ struct pci_host_bridge *pci_create_host_bridge(
>> */
>> host->domain = domain;
>> pci_host_assign_domain_nr(host);
>> + mutex_lock(&pci_host_mutex);
>> + list_for_each_entry(tmp, &pci_host_bridge_list, list) {
>> + if (tmp->domain != host->domain
>> + || pci_host_busn_res_overlap(host, tmp)) {
>
> I think you should construct condition this way:
> + if (tmp->domain == host->domain
> + && pci_host_busn_res_overlap(host, tmp)) {

Good catch! I mistook this in the v8. Tomasz, thanks for your review!

>
> Regards,
> Tomasz
>
>> + pr_warn("pci host bridge pci%04x:%02x exist\n",
>> + host->domain, bus);
>> + mutex_unlock(&pci_host_mutex);
>> + pci_free_resource_list(&host->windows);
>> + kfree(host);
>> + return NULL;
>> + }
>> + }
>> + list_add_tail(&host->list, &pci_host_bridge_list);
>> + mutex_unlock(&pci_host_mutex);
>> +
>> host->dev.release = pci_release_host_bridge_dev;
>> dev_set_name(&host->dev, "pci%04x:%02x",
>> host->domain, bus);
>> @@ -80,6 +115,10 @@ struct pci_host_bridge *pci_create_host_bridge(
>>
>> void pci_free_host_bridge(struct pci_host_bridge *host)
>> {
>> + mutex_lock(&pci_host_mutex);
>> + list_del(&host->list);
>> + mutex_unlock(&pci_host_mutex);
>> +
>> device_unregister(&host->dev);
>> }
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index 25ac741..8517d1b 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -1869,7 +1869,7 @@ static struct pci_bus *__pci_create_root_bus(
>> void *sysdata)
>> {
>> int error;
>> - struct pci_bus *b, *b2;
>> + struct pci_bus *b;
>> struct resource_entry *window;
>> struct device *parent;
>> struct resource *res;
>> @@ -1887,12 +1887,6 @@ static struct pci_bus *__pci_create_root_bus(
>> b->number = b->busn_res.start =
>> pci_host_first_busnr(bridge);
>> pci_bus_assign_domain_nr(b, parent);
>> - b2 = pci_find_bus(pci_domain_nr(b), b->number);
>> - if (b2) {
>> - /* If we already got to this bus through a different bridge, ignore it */
>> - dev_dbg(&b2->dev, "bus already known\n");
>> - goto err_out;
>> - }
>>
>> bridge->bus = b;
>> b->bridge = get_device(&bridge->dev);
>> @@ -1952,7 +1946,6 @@ static struct pci_bus *__pci_create_root_bus(
>>
>> put_dev:
>> put_device(&bridge->dev);
>> -err_out:
>> kfree(b);
>> return NULL;
>> }
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index f189dfb..91cba01 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -407,6 +407,7 @@ struct pci_host_bridge {
>> /* we use default bus resource if no bus resource provided */
>> struct resource busn_res;
>> struct list_head windows; /* resource_entry */
>> + struct list_head list;
>> void (*release_fn)(struct pci_host_bridge *);
>> void *release_data;
>> };
>>
>
> .
>

--
Thanks!
Yijing