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

Tomasz Nowicki
2015-03-25T16:42:14Z

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)) {

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;
> };
>