ACPI: pci_root: simplify acpi_pci_root_add() control flow

By looking up the segment & bus number earlier, we don't have to
worry about cleaning up if it fails.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 38 insertions, 62 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index a8b250783937..0d69c0348c58 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -161,19 +161,22 @@ get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
         return AE_OK;
 }
 
-static acpi_status try_get_root_bridge_busnr(acpi_handle handle, int *busnum)
+static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
+                                             unsigned long long *bus)
 {
         acpi_status status;
+        int busnum;
 
-        *busnum = -1;
+        busnum = -1;
         status =
             acpi_walk_resources(handle, METHOD_NAME__CRS,
-                                get_root_bridge_busnr_callback, busnum);
+                                get_root_bridge_busnr_callback, &busnum);
         if (ACPI_FAILURE(status))
                 return status;
         /* Check if we really get a bus number from _CRS */
-        if (*busnum == -1)
+        if (busnum == -1)
                 return AE_ERROR;
+        *bus = busnum;
         return AE_OK;
 }
 
@@ -363,24 +366,39 @@ EXPORT_SYMBOL(acpi_pci_osc_control_set);
 
 static int __devinit acpi_pci_root_add(struct acpi_device *device)
 {
-        int result = 0;
-        struct acpi_pci_root *root = NULL;
-        acpi_status status = AE_OK;
-        unsigned long long value = 0;
-        acpi_handle handle = NULL;
+        unsigned long long segment, bus;
+        acpi_status status;
+        int result;
+        struct acpi_pci_root *root;
+        acpi_handle handle;
         struct acpi_device *child;
         u32 flags, base_flags;
-        int bus;
 
+        segment = 0;
+        status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
+                                       &segment);
+        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+                printk(KERN_ERR PREFIX "can't evaluate _SEG\n");
+                return -ENODEV;
+        }
 
-        if (!device)
-                return -EINVAL;
+        /* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
+        bus = 0;
+        status = try_get_root_bridge_busnr(device->handle, &bus);
+        if (ACPI_FAILURE(status)) {
+                status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,                                               NULL, &bus);
+                if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+                        printk(KERN_ERR PREFIX
+                             "no bus number in _CRS and can't evaluate _BBN\n");
+                        return -ENODEV;
+                }
+        }
 
         root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
         if (!root)
                 return -ENOMEM;
-        INIT_LIST_HEAD(&root->node);
 
+        INIT_LIST_HEAD(&root->node);
         root->device = device;
         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
@@ -395,54 +413,13 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
         flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
         acpi_pci_osc_support(root, flags);
 
-        /* 
-         * Segment
-         * -------
-         * Obtained via _SEG, if exists, otherwise assumed to be zero (0).
-         */
-        status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
-                                       &value);
-        switch (status) {
-        case AE_OK:
-                root->id.segment = (u16) value;
-                break;
-        case AE_NOT_FOUND:
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-                                  "Assuming segment 0 (no _SEG)\n"));
-                root->id.segment = 0;
-                break;
-        default:
-                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SEG"));
-                result = -ENODEV;
-                goto end;
-        }
-
-        /* 
-         * Bus
-         * ---
-         * Check _CRS first, then _BBN.  If no _BBN, default to zero.
-         */
-        status = try_get_root_bridge_busnr(device->handle, &bus);
-        if (ACPI_SUCCESS(status))
-                root->id.bus = bus;
-        else {
-                status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,                                               NULL, &value);
-                if (ACPI_SUCCESS(status))
-                        root->id.bus = (u16) value;
-                else if (status == AE_NOT_FOUND)
-                        root->id.bus = 0;
-                else {
-                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BBN"));
-                        result = -ENODEV;
-                        goto end;
-                }
-        }
-
         /*
          * Device & Function
          * -----------------
          * Obtained from _ADR (which has already been evaluated for us).
          */
+        root->id.segment = segment & 0xFFFF;
+        root->id.bus = bus & 0xFF;
         root->id.device = device->pnp.bus_address >> 16;
         root->id.function = device->pnp.bus_address & 0xFFFF;
 
@@ -509,13 +486,12 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
         if (flags != base_flags)
                 acpi_pci_osc_support(root, flags);
 
-      end:
-        if (result) {
-                if (!list_empty(&root->node))
-                        list_del(&root->node);
-                kfree(root);
-        }
+        return 0;
 
+end:
+        if (!list_empty(&root->node))
+                list_del(&root->node);
+        kfree(root);
         return result;
 }