[PATCH] reduce nr of ptr derefs in drivers/pci/hotplug/acpiphp_core.c

[Jesper Juhl]

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

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

Please consider applying.


Signed-off-by: Jesper Juhl <jesper.juhl@xxxxxxxxx>
---

 drivers/pci/hotplug/acpiphp_core.c |   44 ++++++++++++++++++++-----------------
 1 files changed, 24 insertions(+), 20 deletions(-)

orig:
   text    data     bss     dec     hex filename
   2018      88      16    2122     84a drivers/pci/hotplug/acpiphp_core.o
patched:
   text    data     bss     dec     hex filename
   1967      88      16    2071     817 drivers/pci/hotplug/acpiphp_core.o

--- linux-2.6.15-rc5-git1-orig/drivers/pci/hotplug/acpiphp_core.c	2005-10-28 02:02:08.000000000 +0200
+++ linux-2.6.15-rc5-git1/drivers/pci/hotplug/acpiphp_core.c	2005-12-11 03:35:53.000000000 +0100
@@ -348,6 +348,8 @@ static void release_slot(struct hotplug_
 static int __init init_slots(void)
 {
 	struct slot *slot;
+	struct hotplug_slot *hotplug_slot;
+	struct hotplug_slot_info *hotplug_slot_info;
 	int retval = -ENOMEM;
 	int i;
 
@@ -360,34 +362,36 @@ static int __init init_slots(void)
 		slot->hotplug_slot = kmalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
 		if (!slot->hotplug_slot)
 			goto error_slot;
-		memset(slot->hotplug_slot, 0, sizeof(struct hotplug_slot));
+		hotplug_slot = slot->hotplug_slot;
+		memset(hotplug_slot, 0, sizeof(struct hotplug_slot));
 
-		slot->hotplug_slot->info = kmalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
-		if (!slot->hotplug_slot->info)
+		hotplug_slot->info = kmalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
+		if (!hotplug_slot->info)
 			goto error_hpslot;
-		memset(slot->hotplug_slot->info, 0, sizeof(struct hotplug_slot_info));
+		hotplug_slot_info = hotplug_slot->info;
+		memset(hotplug_slot_info, 0, sizeof(struct hotplug_slot_info));
 
-		slot->hotplug_slot->name = kmalloc(SLOT_NAME_SIZE, GFP_KERNEL);
-		if (!slot->hotplug_slot->name)
+		hotplug_slot->name = kmalloc(SLOT_NAME_SIZE, GFP_KERNEL);
+		if (!hotplug_slot->name)
 			goto error_info;
 
 		slot->number = i;
 
-		slot->hotplug_slot->private = slot;
-		slot->hotplug_slot->release = &release_slot;
-		slot->hotplug_slot->ops = &acpi_hotplug_slot_ops;
+		hotplug_slot->private = slot;
+		hotplug_slot->release = &release_slot;
+		hotplug_slot->ops = &acpi_hotplug_slot_ops;
 
 		slot->acpi_slot = get_slot_from_id(i);
-		slot->hotplug_slot->info->power_status = acpiphp_get_power_status(slot->acpi_slot);
-		slot->hotplug_slot->info->attention_status = 0;
-		slot->hotplug_slot->info->latch_status = acpiphp_get_latch_status(slot->acpi_slot);
-		slot->hotplug_slot->info->adapter_status = acpiphp_get_adapter_status(slot->acpi_slot);
-		slot->hotplug_slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
-		slot->hotplug_slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;
+		hotplug_slot_info->power_status = acpiphp_get_power_status(slot->acpi_slot);
+		hotplug_slot_info->attention_status = 0;
+		hotplug_slot_info->latch_status = acpiphp_get_latch_status(slot->acpi_slot);
+		hotplug_slot_info->adapter_status = acpiphp_get_adapter_status(slot->acpi_slot);
+		hotplug_slot_info->max_bus_speed = PCI_SPEED_UNKNOWN;
+		hotplug_slot_info->cur_bus_speed = PCI_SPEED_UNKNOWN;
 
 		make_slot_name(slot);
 
-		retval = pci_hp_register(slot->hotplug_slot);
+		retval = pci_hp_register(hotplug_slot);
 		if (retval) {
 			err("pci_hp_register failed with error %d\n", retval);
 			goto error_name;
@@ -395,16 +399,16 @@ static int __init init_slots(void)
 
 		/* add slot to our internal list */
 		list_add(&slot->slot_list, &slot_list);
-		info("Slot [%s] registered\n", slot->hotplug_slot->name);
+		info("Slot [%s] registered\n", hotplug_slot->name);
 	}
 
 	return 0;
 error_name:
-	kfree(slot->hotplug_slot->name);
+	kfree(hotplug_slot->name);
 error_info:
-	kfree(slot->hotplug_slot->info);
+	kfree(hotplug_slot_info);
 error_hpslot:
-	kfree(slot->hotplug_slot);
+	kfree(hotplug_slot);
 error_slot:
 	kfree(slot);
 error:



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/