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Subject[PATCH] Reduce nr of ptr derefs in drivers/pci/hotplug/cpqphp_core.c
Date
Here's a small patch to reduce the nr of pointer dereferences in
drivers/pci/hotplug/cpqphp_core.c

Benefits of this patch:
- micro speed optimization due to fewer pointer derefs
- generated code is slightly smaller
- tiny line length and whitespace cleanup
- better readability

Please consider applying.


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

drivers/pci/hotplug/cpqphp_core.c | 121 +++++++++++++++++++++-----------------
1 files changed, 67 insertions(+), 54 deletions(-)

orig:
text data bss dec hex filename
12813 416 1080 14309 37e5 drivers/pci/hotplug/cpqphp_core.o
patched:
text data bss dec hex filename
12799 416 1080 14295 37d7 drivers/pci/hotplug/cpqphp_core.o

--- linux-2.6.15-rc5-git1-orig/drivers/pci/hotplug/cpqphp_core.c 2005-12-04 18:48:04.000000000 +0100
+++ linux-2.6.15-rc5-git1/drivers/pci/hotplug/cpqphp_core.c 2005-12-11 04:33:05.000000000 +0100
@@ -327,7 +327,9 @@ static int ctrl_slot_setup(struct contro
void __iomem *smbios_start,
void __iomem *smbios_table)
{
- struct slot *new_slot;
+ struct slot *slot;
+ struct hotplug_slot *hotplug_slot;
+ struct hotplug_slot_info *hotplug_slot_info;
u8 number_of_slots;
u8 slot_device;
u8 slot_number;
@@ -345,93 +347,105 @@ static int ctrl_slot_setup(struct contro
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->bus;
- new_slot->device = slot_device;
- new_slot->number = slot_number;
- dbg("slot->number = %d\n",new_slot->number);
+ slot->ctrl = ctrl;
+ slot->bus = ctrl->bus;
+ slot->device = slot_device;
+ slot->number = slot_number;
+ dbg("slot->number = %d\n", slot->number);

slot_entry = get_SMBIOS_entry(smbios_start, smbios_table, 9,
slot_entry);

- while (slot_entry && (readw(slot_entry + SMBIOS_SLOT_NUMBER) != new_slot->number)) {
+ while (slot_entry && (readw(slot_entry + SMBIOS_SLOT_NUMBER) !=
+ slot->number)) {
slot_entry = get_SMBIOS_entry(smbios_start,
smbios_table, 9, slot_entry);
}

- new_slot->p_sm_slot = slot_entry;
+ slot->p_sm_slot = slot_entry;

- init_timer(&new_slot->task_event);
- new_slot->task_event.expires = jiffies + 5 * HZ;
- new_slot->task_event.function = cpqhp_pushbutton_thread;
+ init_timer(&slot->task_event);
+ slot->task_event.expires = jiffies + 5 * HZ;
+ slot->task_event.function = cpqhp_pushbutton_thread;

//FIXME: these capabilities aren't used but if they are
// they need to be correctly implemented
- new_slot->capabilities |= PCISLOT_REPLACE_SUPPORTED;
- new_slot->capabilities |= PCISLOT_INTERLOCK_SUPPORTED;
+ slot->capabilities |= PCISLOT_REPLACE_SUPPORTED;
+ slot->capabilities |= PCISLOT_INTERLOCK_SUPPORTED;

- if (is_slot64bit(new_slot))
- new_slot->capabilities |= PCISLOT_64_BIT_SUPPORTED;
- if (is_slot66mhz(new_slot))
- new_slot->capabilities |= PCISLOT_66_MHZ_SUPPORTED;
+ if (is_slot64bit(slot))
+ slot->capabilities |= PCISLOT_64_BIT_SUPPORTED;
+ if (is_slot66mhz(slot))
+ slot->capabilities |= PCISLOT_66_MHZ_SUPPORTED;
if (ctrl->speed == PCI_SPEED_66MHz)
- new_slot->capabilities |= PCISLOT_66_MHZ_OPERATION;
+ slot->capabilities |= PCISLOT_66_MHZ_OPERATION;

- ctrl_slot = slot_device - (readb(ctrl->hpc_reg + SLOT_MASK) >> 4);
+ ctrl_slot =
+ slot_device - (readb(ctrl->hpc_reg + SLOT_MASK) >> 4);

// Check presence
- new_slot->capabilities |= ((((~tempdword) >> 23) | ((~tempdword) >> 15)) >> ctrl_slot) & 0x02;
+ slot->capabilities |=
+ ((((~tempdword) >> 23) |
+ ((~tempdword) >> 15)) >> ctrl_slot) & 0x02;
// Check the switch state
- new_slot->capabilities |= ((~tempdword & 0xFF) >> ctrl_slot) & 0x01;
+ slot->capabilities |=
+ ((~tempdword & 0xFF) >> ctrl_slot) & 0x01;
// Check the slot enable
- new_slot->capabilities |= ((read_slot_enable(ctrl) << 2) >> ctrl_slot) & 0x04;
+ slot->capabilities |=
+ ((read_slot_enable(ctrl) << 2) >> ctrl_slot) & 0x04;

/* register this slot with the hotplug pci core */
- new_slot->hotplug_slot->release = &release_slot;
- new_slot->hotplug_slot->private = new_slot;
- make_slot_name(new_slot->hotplug_slot->name, SLOT_NAME_SIZE, new_slot);
- new_slot->hotplug_slot->ops = &cpqphp_hotplug_slot_ops;
+ hotplug_slot->release = &release_slot;
+ hotplug_slot->private = slot;
+ make_slot_name(hotplug_slot->name, SLOT_NAME_SIZE, slot);
+ hotplug_slot->ops = &cpqphp_hotplug_slot_ops;

- new_slot->hotplug_slot->info->power_status = get_slot_enabled(ctrl, new_slot);
- new_slot->hotplug_slot->info->attention_status = cpq_get_attention_status(ctrl, new_slot);
- new_slot->hotplug_slot->info->latch_status = cpq_get_latch_status(ctrl, new_slot);
- new_slot->hotplug_slot->info->adapter_status = get_presence_status(ctrl, new_slot);
+ hotplug_slot_info->power_status = get_slot_enabled(ctrl, slot);
+ hotplug_slot_info->attention_status =
+ cpq_get_attention_status(ctrl, slot);
+ hotplug_slot_info->latch_status =
+ cpq_get_latch_status(ctrl, slot);
+ hotplug_slot_info->adapter_status =
+ get_presence_status(ctrl, slot);

- dbg ("registering bus %d, dev %d, number %d, "
+ dbg("registering bus %d, dev %d, number %d, "
"ctrl->slot_device_offset %d, slot %d\n",
- new_slot->bus, new_slot->device,
- new_slot->number, ctrl->slot_device_offset,
+ slot->bus, slot->device,
+ slot->number, ctrl->slot_device_offset,
slot_number);
- result = pci_hp_register (new_slot->hotplug_slot);
+ result = pci_hp_register(hotplug_slot);
if (result) {
- err ("pci_hp_register failed with error %d\n", 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++;
@@ -439,15 +453,14 @@ static int ctrl_slot_setup(struct contro
}

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;
}


-
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