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

Previously, pci_scan_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_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_bus() and do it after any
resource assignment in the callers.

[bhelgaas: changelog, check for failure in mcf_pci_init()]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
CC: Guan Xuetao <gxt@mprc.pku.edu.cn>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>

6 files changed, 19 insertions, 11 deletions

diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c
index 837c0fa58317..700686d04869 100644
--- a/arch/alpha/kernel/sys_nautilus.c
+++ b/arch/alpha/kernel/sys_nautilus.c
@@ -207,6 +207,9 @@ nautilus_init_pci(void)
 
         /* Scan our single hose.  */
         bus = pci_scan_bus(0, alpha_mv.pci_ops, hose);
+        if (!bus)
+                return;
+
         hose->bus = bus;
         pcibios_claim_one_bus(bus);
 
@@ -253,6 +256,7 @@ nautilus_init_pci(void)
            for the root bus, so just clear it. */
         bus->self = NULL;
         pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq);
+        pci_bus_add_devices(bus);
 }
 
 /*
diff --git a/arch/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c
index df9679238b6d..821de928dc3f 100644
--- a/arch/m68k/coldfire/pci.c
+++ b/arch/m68k/coldfire/pci.c
@@ -313,12 +313,16 @@ static int __init mcf_pci_init(void)
         schedule_timeout(msecs_to_jiffies(200));
 
         rootbus = pci_scan_bus(0, &mcf_pci_ops, NULL);
+        if (!rootbus)
+                return -ENODEV;
+
         rootbus->resource[0] = &mcf_pci_io;
         rootbus->resource[1] = &mcf_pci_mem;
 
         pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq);
         pci_bus_size_bridges(rootbus);
         pci_bus_assign_resources(rootbus);
+        pci_bus_add_devices(rootbus);
         return 0;
 }
 
diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
index 6cc78c213c01..24384e1dc33d 100644
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -391,12 +391,16 @@ static void __init pcic_pbm_scan_bus(struct linux_pcic *pcic)
         struct linux_pbm_info *pbm = &pcic->pbm;
 
         pbm->pci_bus = pci_scan_bus(pbm->pci_first_busno, &pcic_ops, pbm);
+        if (!pbm->pci_bus)
+                return;
+
 #if 0 /* deadwood transplanted from sparc64 */
         pci_fill_in_pbm_cookies(pbm->pci_bus, pbm, pbm->prom_node);
         pci_record_assignments(pbm, pbm->pci_bus);
         pci_assign_unassigned(pbm, pbm->pci_bus);
         pci_fixup_irq(pbm, pbm->pci_bus);
 #endif
+        pci_bus_add_devices(pbm->pci_bus);
 }
 
 /*
diff --git a/arch/unicore32/kernel/pci.c b/arch/unicore32/kernel/pci.c
index 374a055a8e6b..d45fa5f3e9c4 100644
--- a/arch/unicore32/kernel/pci.c
+++ b/arch/unicore32/kernel/pci.c
@@ -266,17 +266,10 @@ static int __init pci_common_init(void)
         pci_fixup_irqs(pci_common_swizzle, pci_puv3_map_irq);
 
         if (!pci_has_flag(PCI_PROBE_ONLY)) {
-                /*
-                 * Size the bridge windows.
-                 */
                 pci_bus_size_bridges(puv3_bus);
-
-                /*
-                 * Assign resources.
-                 */
                 pci_bus_assign_resources(puv3_bus);
         }
-
+        pci_bus_add_devices(puv3_bus);
         return 0;
 }
 subsys_initcall(pci_common_init);
diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c
index 96c5c729cdbc..15302475f5b7 100644
--- a/drivers/pci/hotplug/ibmphp_core.c
+++ b/drivers/pci/hotplug/ibmphp_core.c
@@ -738,7 +738,7 @@ static void ibm_unconfigure_device(struct pci_func *func)
  */
 static u8 bus_structure_fixup(u8 busno)
 {
-        struct pci_bus *bus;
+        struct pci_bus *bus, *b;
         struct pci_dev *dev;
         u16 l;
 
@@ -765,7 +765,11 @@ static u8 bus_structure_fixup(u8 busno)
                                         (l != 0x0000) && (l != 0xffff)) {
                         debug("%s - Inside bus_structure_fixup()\n",
                                                         __func__);
-                        pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL);
+                        b = pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL);
+                        if (!b)
+                                continue;
+
+                        pci_bus_add_devices(b);
                         break;
                 }
         }
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8d2f400e96cb..88604f29d140 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2123,7 +2123,6 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops,
         b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources);
         if (b) {
                 pci_scan_child_bus(b);
-                pci_bus_add_devices(b);
         } else {
                 pci_free_resource_list(&resources);
         }