PCI: Assign resources before drivers claim devices (pci_scan_root_bus())

Previously, pci_scan_root_bus() created a root PCI bus, enumerated the
devices on it, and called pci_bus_add_devices(), which made the devices
available for drivers to claim them.

Most callers assigned resources to devices after pci_scan_root_bus()
returns, which may be after drivers have claimed the devices.  This is
incorrect; the PCI core should not change device resources while a driver
is managing the device.

Remove pci_bus_add_devices() from pci_scan_root_bus() and do it after any
resource assignment in the callers.

Note that ARM's pci_common_init_dev() already called pci_bus_add_devices()
after pci_scan_root_bus(), so we only need to remove the first call:

  pci_common_init_dev
    pcibios_init_hw
      pci_scan_root_bus
        pci_bus_add_devices        # first call
    pci_bus_assign_resources
    pci_bus_add_devices            # second call

[bhelgaas: changelog, drop "root_bus" var in alpha common_init_pci(),
return failure earlier in mn10300, add "return" in x86 pcibios_scan_root(),
return early if xtensa platform_pcibios_fixup() fails]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>
CC: David Howells <dhowells@redhat.com>
CC: Tony Luck <tony.luck@intel.com>
CC: Michal Simek <monstr@monstr.eu>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Chris Metcalf <cmetcalf@ezchip.com>
CC: Chris Zankel <chris@zankel.net>
CC: Max Filippov <jcmvbkbc@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>

15 files changed, 47 insertions, 6 deletions

diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c
index 98a1525fa164..82f738e5d54c 100644
--- a/arch/alpha/kernel/pci.c
+++ b/arch/alpha/kernel/pci.c
@@ -338,6 +338,8 @@ common_init_pci(void)
 
                 bus = pci_scan_root_bus(NULL, next_busno, alpha_mv.pci_ops,
                                         hose, &resources);
+                if (!bus)
+                        continue;
                 hose->bus = bus;
                 hose->need_domain_info = need_domain_info;
                 next_busno = bus->busn_res.end + 1;
@@ -353,6 +355,11 @@ common_init_pci(void)
 
         pci_assign_unassigned_resources();
         pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq);
+        for (hose = hose_head; hose; hose = hose->next) {
+                bus = hose->bus;
+                if (bus)
+                        pci_bus_add_devices(bus);
+        }
 }
 
 
diff --git a/arch/frv/mb93090-mb00/pci-vdk.c b/arch/frv/mb93090-mb00/pci-vdk.c
index b073f4d771a5..f211839e2cae 100644
--- a/arch/frv/mb93090-mb00/pci-vdk.c
+++ b/arch/frv/mb93090-mb00/pci-vdk.c
@@ -316,6 +316,7 @@ void pcibios_fixup_bus(struct pci_bus *bus)
 
 int __init pcibios_init(void)
 {
+        struct pci_bus *bus;
         struct pci_ops *dir = NULL;
         LIST_HEAD(resources);
 
@@ -383,12 +384,15 @@ int __init pcibios_init(void)
         printk("PCI: Probing PCI hardware\n");
         pci_add_resource(&resources, &pci_ioport_resource);
         pci_add_resource(&resources, &pci_iomem_resource);
-        pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources);
+        bus = pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources);
 
         pcibios_irq_init();
         pcibios_fixup_irqs();
         pcibios_resource_survey();
+        if (!bus)
+                return 0;
 
+        pci_bus_add_devices(bus);
         return 0;
 }
 
diff --git a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c
index 0b5ce82d203d..1be65eb074ec 100644
--- a/arch/ia64/sn/kernel/io_init.c
+++ b/arch/ia64/sn/kernel/io_init.c
@@ -271,7 +271,9 @@ sn_pci_controller_fixup(int segment, int busnum, struct pci_bus *bus)
         if (bus == NULL) {
                 kfree(res);
                 kfree(controller);
+                return;
         }
+        pci_bus_add_devices(bus);
 }
 
 /*
diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index 48528fb81eff..ae838ed5fcf2 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -1382,6 +1382,10 @@ static int __init pcibios_init(void)
 
         /* Call common code to handle resource allocation */
         pcibios_resource_survey();
+        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
+                if (hose->bus)
+                        pci_bus_add_devices(hose->bus);
+        }
 
         return 0;
 }
diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index 1bf60b127377..9eb54b557c9f 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -114,6 +114,7 @@ static void pcibios_scanbus(struct pci_controller *hose)
                         pci_bus_size_bridges(bus);
                         pci_bus_assign_resources(bus);
                 }
+                pci_bus_add_devices(bus);
         }
 }
 
diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c
index 613ca1e55b4b..3dfe2d31c67b 100644
--- a/arch/mn10300/unit-asb2305/pci.c
+++ b/arch/mn10300/unit-asb2305/pci.c
@@ -342,6 +342,7 @@ static int __init pcibios_init(void)
 {
         resource_size_t io_offset, mem_offset;
         LIST_HEAD(resources);
+        struct pci_bus *bus;
 
         ioport_resource.start   = 0xA0000000;
         ioport_resource.end     = 0xDFFFFFFF;
@@ -371,11 +372,14 @@ static int __init pcibios_init(void)
 
         pci_add_resource_offset(&resources, &pci_ioport_resource, io_offset);
         pci_add_resource_offset(&resources, &pci_iomem_resource, mem_offset);
-        pci_scan_root_bus(NULL, 0, &pci_direct_ampci, NULL, &resources);
+        bus = pci_scan_root_bus(NULL, 0, &pci_direct_ampci, NULL, &resources);
+        if (!bus)
+                return 0;
 
         pcibios_irq_init();
         pcibios_fixup_irqs();
         pcibios_resource_survey();
+        pci_bus_add_devices(bus);
         return 0;
 }
 
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 753a56731951..a2a7391c0b9a 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -776,8 +776,8 @@ static int zpci_scan_bus(struct zpci_dev *zdev)
                 zpci_cleanup_bus_resources(zdev);
                 return -EIO;
         }
-
         zdev->bus->max_bus_speed = zdev->max_bus_speed;
+        pci_bus_add_devices(zdev->bus);
         return 0;
 }
 
diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c
index 1bc09ee7948f..efc10519916a 100644
--- a/arch/sh/drivers/pci/pci.c
+++ b/arch/sh/drivers/pci/pci.c
@@ -69,6 +69,7 @@ static void pcibios_scanbus(struct pci_channel *hose)
 
                 pci_bus_size_bridges(bus);
                 pci_bus_assign_resources(bus);
+                pci_bus_add_devices(bus);
         } else {
                 pci_free_resource_list(&resources);
         }
diff --git a/arch/sparc/kernel/leon_pci.c b/arch/sparc/kernel/leon_pci.c
index 899b7203a4e4..297107679fdf 100644
--- a/arch/sparc/kernel/leon_pci.c
+++ b/arch/sparc/kernel/leon_pci.c
@@ -40,6 +40,7 @@ void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
 
                 /* Assign devices with resources */
                 pci_assign_unassigned_resources();
+                pci_bus_add_devices(root_bus);
         } else {
                 pci_free_resource_list(&resources);
         }
diff --git a/arch/tile/kernel/pci.c b/arch/tile/kernel/pci.c
index 325df47f114d..9475a74cd53a 100644
--- a/arch/tile/kernel/pci.c
+++ b/arch/tile/kernel/pci.c
@@ -339,6 +339,8 @@ int __init pcibios_init(void)
                         struct pci_bus *next_bus;
                         struct pci_dev *dev;
 
+                        pci_bus_add_devices(root_bus);
+
                         list_for_each_entry(dev, &root_bus->devices, bus_list) {
                                 /*
                                  * Find the PCI host controller, ie. the 1st
diff --git a/arch/tile/kernel/pci_gx.c b/arch/tile/kernel/pci_gx.c
index 2c95f37ebbed..b1df847d0686 100644
--- a/arch/tile/kernel/pci_gx.c
+++ b/arch/tile/kernel/pci_gx.c
@@ -1030,6 +1030,8 @@ int __init pcibios_init(void)
 alloc_mem_map_failed:
                         break;
                 }
+
+                pci_bus_add_devices(root_bus);
         }
 
         return 0;
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 3d2612b68694..95a0ba70376b 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -490,7 +490,9 @@ void pcibios_scan_root(int busnum)
         if (!bus) {
                 pci_free_resource_list(&resources);
                 kfree(sd);
+                return;
         }
+        pci_bus_add_devices(bus);
 }
 
 void __init pcibios_set_cache_line_size(void)
diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
index 5b3403388d7f..b848cc3dc913 100644
--- a/arch/xtensa/kernel/pci.c
+++ b/arch/xtensa/kernel/pci.c
@@ -174,7 +174,7 @@ static int __init pcibios_init(void)
         struct pci_controller *pci_ctrl;
         struct list_head resources;
         struct pci_bus *bus;
-        int next_busno = 0;
+        int next_busno = 0, ret;
 
         printk("PCI: Probing PCI hardware\n");
 
@@ -185,14 +185,25 @@ static int __init pcibios_init(void)
                 pci_controller_apertures(pci_ctrl, &resources);
                 bus = pci_scan_root_bus(NULL, pci_ctrl->first_busno,
                                         pci_ctrl->ops, pci_ctrl, &resources);
+                if (!bus)
+                        continue;
+
                 pci_ctrl->bus = bus;
                 pci_ctrl->last_busno = bus->busn_res.end;
                 if (next_busno <= pci_ctrl->last_busno)
                         next_busno = pci_ctrl->last_busno+1;
         }
         pci_bus_count = next_busno;
+        ret = platform_pcibios_fixup();
+        if (ret)
+                return ret;
 
-        return platform_pcibios_fixup();
+        for (pci_ctrl = pci_ctrl_head; pci_ctrl; pci_ctrl = pci_ctrl->next) {
+                if (pci_ctrl->bus)
+                        pci_bus_add_devices(pci_ctrl->bus);
+        }
+
+        return 0;
 }
 
 subsys_initcall(pcibios_init);
diff --git a/drivers/pci/host/pci-versatile.c b/drivers/pci/host/pci-versatile.c
index 1ec694a52379..e3a2450db2b8 100644
--- a/drivers/pci/host/pci-versatile.c
+++ b/drivers/pci/host/pci-versatile.c
@@ -214,6 +214,7 @@ static int versatile_pci_probe(struct platform_device *pdev)
 
         pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
         pci_assign_unassigned_bus_resources(bus);
+        pci_bus_add_devices(bus);
 
         return 0;
 }
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 88604f29d140..8ef0375ea314 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2087,7 +2087,6 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
         if (!found)
                 pci_bus_update_busn_res_end(b, max);
 
-        pci_bus_add_devices(b);
         return b;
 }
 EXPORT_SYMBOL(pci_scan_root_bus);