This patch makes PCI host bridge/bus creating and destroying logic
symmetric by using device_initialize()/device_add()/device_del()/put_device()
pairs as discussed in thread at:
http://comments.gmane.org/gmane.linux.kernel.pci/22073

It also fixes a bug in error recovery path in pci_create_root_bus()
which may kfree() an in-use host bridge object.

Signed-off-by: Jiang Liu <jiang....@huawei.com>
Cc: Yinghai Lu <ying...@kernel.org>
---
 drivers/pci/probe.c  | 84 +++++++++++++++++++++++-----------------------------
 drivers/pci/remove.c |  3 +-
 2 files changed, 39 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d5d18a0..c9a5ce7 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -451,7 +451,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
        }
 }
 
-static struct pci_bus * pci_alloc_bus(void)
+static struct pci_bus *pci_alloc_bus(struct pci_ops *ops, void *sd, int bus)
 {
        struct pci_bus *b;
 
@@ -464,10 +464,32 @@ static struct pci_bus * pci_alloc_bus(void)
                INIT_LIST_HEAD(&b->resources);
                b->max_bus_speed = PCI_SPEED_UNKNOWN;
                b->cur_bus_speed = PCI_SPEED_UNKNOWN;
+               b->sysdata = sd;
+               b->ops = ops;
+               b->number = bus;
+               b->busn_res.start = bus;
+               b->busn_res.end = 0xff;
+               b->busn_res.flags = IORESOURCE_BUS;
+               b->dev.class = &pcibus_class;
+               dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
+               device_initialize(&b->dev);
        }
+
        return b;
 }
 
+static void pci_release_host_bridge_dev(struct device *dev)
+{
+       struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
+
+       if (bridge->release_fn)
+               bridge->release_fn(bridge);
+
+       pci_free_resource_list(&bridge->windows);
+
+       kfree(bridge);
+}
+
 static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
 {
        struct pci_host_bridge *bridge;
@@ -476,6 +498,10 @@ static struct pci_host_bridge 
*pci_alloc_host_bridge(struct pci_bus *b)
        if (bridge) {
                INIT_LIST_HEAD(&bridge->windows);
                bridge->bus = b;
+               bridge->dev.release = pci_release_host_bridge_dev;
+               dev_set_name(&bridge->dev, "pci%04x:%02x",
+                            pci_domain_nr(b), b->number);
+               device_initialize(&bridge->dev);
        }
 
        return bridge;
@@ -628,28 +654,13 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus 
*parent,
        /*
         * Allocate a new bus, and inherit stuff from the parent..
         */
-       child = pci_alloc_bus();
+       child = pci_alloc_bus(parent->ops, parent->sysdata, busnr);
        if (!child)
                return NULL;
 
        child->parent = parent;
-       child->ops = parent->ops;
-       child->sysdata = parent->sysdata;
        child->bus_flags = parent->bus_flags;
-
-       /* initialize some portions of the bus device, but don't register it
-        * now as the parent is not properly set up yet.
-        */
-       child->dev.class = &pcibus_class;
-       dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);
-
-       /*
-        * Set up the primary, secondary and subordinate
-        * bus numbers.
-        */
-       child->number = child->busn_res.start = busnr;
        child->primary = parent->busn_res.start;
-       child->busn_res.end = 0xff;
 
        if (!bridge) {
                child->dev.parent = parent->bridge;
@@ -670,7 +681,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus 
*parent,
        bridge->subordinate = child;
 
 add_dev:
-       ret = device_register(&child->dev);
+       ret = device_add(&child->dev);
        WARN_ON(ret < 0);
 
        pcibios_add_bus(child);
@@ -1189,18 +1200,6 @@ int pci_cfg_space_size(struct pci_dev *dev)
        return PCI_CFG_SPACE_SIZE;
 }
 
-static void pci_release_bus_bridge_dev(struct device *dev)
-{
-       struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
-
-       if (bridge->release_fn)
-               bridge->release_fn(bridge);
-
-       pci_free_resource_list(&bridge->windows);
-
-       kfree(bridge);
-}
-
 struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
 {
        struct pci_dev *dev;
@@ -1688,13 +1687,10 @@ struct pci_bus *pci_create_root_bus(struct device 
*parent, int bus,
        char bus_addr[64];
        char *fmt;
 
-       b = pci_alloc_bus();
+       b = pci_alloc_bus(ops, sysdata, bus);
        if (!b)
                return NULL;
 
-       b->sysdata = sysdata;
-       b->ops = ops;
-       b->number = b->busn_res.start = bus;
        b2 = pci_find_bus(pci_domain_nr(b), bus);
        if (b2) {
                /* If we already got to this bus through a different bridge, 
ignore it */
@@ -1706,27 +1702,22 @@ struct pci_bus *pci_create_root_bus(struct device 
*parent, int bus,
        if (!bridge)
                goto err_out;
 
-       bridge->dev.parent = parent;
-       bridge->dev.release = pci_release_bus_bridge_dev;
-       dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
        error = pcibios_root_bridge_prepare(bridge);
        if (error)
                goto bridge_dev_reg_err;
 
-       error = device_register(&bridge->dev);
+       bridge->dev.parent = parent;
+       error = device_add(&bridge->dev);
        if (error)
                goto bridge_dev_reg_err;
+
        b->bridge = get_device(&bridge->dev);
        device_enable_async_suspend(b->bridge);
        pci_set_bus_of_node(b);
-
        if (!parent)
                set_dev_node(b->bridge, pcibus_to_node(b));
-
-       b->dev.class = &pcibus_class;
        b->dev.parent = b->bridge;
-       dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
-       error = device_register(&b->dev);
+       error = device_add(&b->dev);
        if (error)
                goto class_dev_reg_err;
 
@@ -1769,12 +1760,11 @@ struct pci_bus *pci_create_root_bus(struct device 
*parent, int bus,
        return b;
 
 class_dev_reg_err:
-       put_device(&bridge->dev);
-       device_unregister(&bridge->dev);
+       device_del(&bridge->dev);
 bridge_dev_reg_err:
-       kfree(bridge);
+       put_device(&bridge->dev);
 err_out:
-       kfree(b);
+       put_device(&b->dev);
        return NULL;
 }
 
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 8fc54b7..b0ce875 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -52,7 +52,8 @@ void pci_remove_bus(struct pci_bus *bus)
        up_write(&pci_bus_sem);
        pci_remove_legacy_files(bus);
        pcibios_remove_bus(bus);
-       device_unregister(&bus->dev);
+       device_del(&bus->dev);
+       put_device(&bus->dev);
 }
 EXPORT_SYMBOL(pci_remove_bus);
 
-- 
1.8.1.2

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