[PATCH] PCI: Reduce nr of ptr derefs in drivers/pci/hotplug/pciehp_core.c

Here's a small patch to reduce the nr. of pointer dereferences in
drivers/pci/hotplug/pciehp_core.c

Benefits:
 - micro speed optimization due to fewer pointer derefs
 - generated code is slightly smaller
 - small line length cleanup
 - better readability

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 50 insertions, 40 deletions

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 8df704860348..986e202e0b0b 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -103,7 +103,10 @@ static void release_slot(struct hotplug_slot *hotplug_slot)
 
 static int init_slots(struct controller *ctrl)
 {
-        struct slot *new_slot;
+        struct slot *slot;
+        struct hpc_ops *hpc_ops;
+        struct hotplug_slot *hotplug_slot;
+        struct hotplug_slot_info *hotplug_slot_info;
         u8 number_of_slots;
         u8 slot_device;
         u32 slot_number;
@@ -114,59 +117,66 @@ static int init_slots(struct controller *ctrl)
         slot_number = ctrl->first_slot;
 
         while (number_of_slots) {
-                new_slot = kmalloc(sizeof(*new_slot), GFP_KERNEL);
-                if (!new_slot)
+                slot = kmalloc(sizeof(*slot), GFP_KERNEL);
+                if (!slot)
                         goto error;
 
-                memset(new_slot, 0, sizeof(struct slot));
-                new_slot->hotplug_slot =
-                                kmalloc(sizeof(*(new_slot->hotplug_slot)),
+                memset(slot, 0, sizeof(struct slot));
+                slot->hotplug_slot =
+                                kmalloc(sizeof(*(slot->hotplug_slot)),
                                                 GFP_KERNEL);
-                if (!new_slot->hotplug_slot)
+                if (!slot->hotplug_slot)
                         goto error_slot;
-                memset(new_slot->hotplug_slot, 0, sizeof(struct hotplug_slot));
+                hotplug_slot = slot->hotplug_slot;
+                memset(hotplug_slot, 0, sizeof(struct hotplug_slot));
 
-                new_slot->hotplug_slot->info =
-                        kmalloc(sizeof(*(new_slot->hotplug_slot->info)),
+                hotplug_slot->info =
+                        kmalloc(sizeof(*(hotplug_slot->info)),
                                                 GFP_KERNEL);
-                if (!new_slot->hotplug_slot->info)
+                if (!hotplug_slot->info)
                         goto error_hpslot;
-                memset(new_slot->hotplug_slot->info, 0,
+                hotplug_slot_info = hotplug_slot->info;
+                memset(hotplug_slot_info, 0,
                                         sizeof(struct hotplug_slot_info));
-                new_slot->hotplug_slot->name = kmalloc(SLOT_NAME_SIZE,
-                                                GFP_KERNEL);
-                if (!new_slot->hotplug_slot->name)
+                hotplug_slot->name = kmalloc(SLOT_NAME_SIZE, GFP_KERNEL);
+                if (!hotplug_slot->name)
                         goto error_info;
 
-                new_slot->ctrl = ctrl;
-                new_slot->bus = ctrl->slot_bus;
-                new_slot->device = slot_device;
-                new_slot->hpc_ops = ctrl->hpc_ops;
+                slot->ctrl = ctrl;
+                slot->bus = ctrl->slot_bus;
+                slot->device = slot_device;
+                slot->hpc_ops = hpc_ops = ctrl->hpc_ops;
 
-                new_slot->number = ctrl->first_slot;
-                new_slot->hp_slot = slot_device - ctrl->slot_device_offset;
+                slot->number = ctrl->first_slot;
+                slot->hp_slot = slot_device - ctrl->slot_device_offset;
 
                 /* register this slot with the hotplug pci core */
-                new_slot->hotplug_slot->private = new_slot;
-                new_slot->hotplug_slot->release = &release_slot;
-                make_slot_name(new_slot->hotplug_slot->name, SLOT_NAME_SIZE, new_slot);
-                new_slot->hotplug_slot->ops = &pciehp_hotplug_slot_ops;
-
-                new_slot->hpc_ops->get_power_status(new_slot, &(new_slot->hotplug_slot->info->power_status));
-                new_slot->hpc_ops->get_attention_status(new_slot, &(new_slot->hotplug_slot->info->attention_status));
-                new_slot->hpc_ops->get_latch_status(new_slot, &(new_slot->hotplug_slot->info->latch_status));
-                new_slot->hpc_ops->get_adapter_status(new_slot, &(new_slot->hotplug_slot->info->adapter_status));
-
-                dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x slot_device_offset=%x\n", 
-                        new_slot->bus, new_slot->device, new_slot->hp_slot, new_slot->number, ctrl->slot_device_offset);
-                result = pci_hp_register (new_slot->hotplug_slot);
+                hotplug_slot->private = slot;
+                hotplug_slot->release = &release_slot;
+                make_slot_name(hotplug_slot->name, SLOT_NAME_SIZE, slot);
+                hotplug_slot->ops = &pciehp_hotplug_slot_ops;
+
+                hpc_ops->get_power_status(slot,
+                        &(hotplug_slot_info->power_status));
+                hpc_ops->get_attention_status(slot,
+                        &(hotplug_slot_info->attention_status));
+                hpc_ops->get_latch_status(slot,
+                        &(hotplug_slot_info->latch_status));
+                hpc_ops->get_adapter_status(slot,
+                        &(hotplug_slot_info->adapter_status));
+
+                dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
+                        "slot_device_offset=%x\n",
+                        slot->bus, slot->device, slot->hp_slot, slot->number,
+                        ctrl->slot_device_offset);
+                result = pci_hp_register(hotplug_slot);
                 if (result) {
                         err ("pci_hp_register failed with error %d\n", result);
                         goto error_name;
                 }
 
-                new_slot->next = ctrl->slot;
-                ctrl->slot = new_slot;
+                slot->next = ctrl->slot;
+                ctrl->slot = slot;
 
                 number_of_slots--;
                 slot_device++;
@@ -176,13 +186,13 @@ static int init_slots(struct controller *ctrl)
         return 0;
 
 error_name:
-        kfree(new_slot->hotplug_slot->name);
+        kfree(hotplug_slot->name);
 error_info:
-        kfree(new_slot->hotplug_slot->info);
+        kfree(hotplug_slot_info);
 error_hpslot:
-        kfree(new_slot->hotplug_slot);
+        kfree(hotplug_slot);
 error_slot:
-        kfree(new_slot);
+        kfree(slot);
 error:
         return result;
 }