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linux/drivers/pci/hotplug/pcihp_skeleton.c
Julia Lawall 83d0571073 PCI: hotplug: ensure a consistent return value in error case 
Typically, the return value desired for the failure of a function with an
integer return value is a negative integer.  In these cases, the return
value is sometimes a negative integer and sometimes 0, due to a subsequent
initialization of the return variable within the loop.

A simplified version of the semantic match that finds this problem is:
(http://coccinelle.lip6.fr/)

//<smpl>
@r exists@
identifier ret;
position p;
constant C;
expression e1,e3,e4;
statement S;
@@

ret = -C
... when != ret = e3
    when any
if@p (...) S
... when any
if (\(ret != 0\|ret < 0\|ret > 0\) || ...) { ... return ...; }
... when != ret = e3
    when any
*if@p (...)
{
  ... when != ret = e4
  return ret;
}
//</smpl>

[bhelgaas: squashed into one patch]
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-07-16 09:25:56 -06:00

366 lines
8.8 KiB
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/*
* PCI Hot Plug Controller Skeleton Driver - 0.3
*
* Copyright (C) 2001,2003 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001,2003 IBM Corp.
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* This driver is to be used as a skeleton driver to show how to interface
* with the pci hotplug core easily.
*
* Send feedback to <greg@kroah.com>
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/init.h>
#define SLOT_NAME_SIZE 10
struct slot {
u8 number;
struct hotplug_slot *hotplug_slot;
struct list_head slot_list;
char name[SLOT_NAME_SIZE];
};
static LIST_HEAD(slot_list);
#define MY_NAME "pcihp_skeleton"
#define dbg(format, arg...) \
do { \
if (debug) \
printk (KERN_DEBUG "%s: " format "\n", \
MY_NAME , ## arg); \
} while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME , ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME , ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME , ## arg)
/* local variables */
static bool debug;
static int num_slots;
#define DRIVER_VERSION "0.3"
#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>"
#define DRIVER_DESC "Hot Plug PCI Controller Skeleton Driver"
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
static int enable_slot (struct hotplug_slot *slot);
static int disable_slot (struct hotplug_slot *slot);
static int set_attention_status (struct hotplug_slot *slot, u8 value);
static int hardware_test (struct hotplug_slot *slot, u32 value);
static int get_power_status (struct hotplug_slot *slot, u8 *value);
static int get_attention_status (struct hotplug_slot *slot, u8 *value);
static int get_latch_status (struct hotplug_slot *slot, u8 *value);
static int get_adapter_status (struct hotplug_slot *slot, u8 *value);
static struct hotplug_slot_ops skel_hotplug_slot_ops = {
.enable_slot = enable_slot,
.disable_slot = disable_slot,
.set_attention_status = set_attention_status,
.hardware_test = hardware_test,
.get_power_status = get_power_status,
.get_attention_status = get_attention_status,
.get_latch_status = get_latch_status,
.get_adapter_status = get_adapter_status,
};
static int enable_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in code here to enable the specified slot
*/
return retval;
}
static int disable_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in code here to disable the specified slot
*/
return retval;
}
static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
switch (status) {
case 0:
/*
* Fill in code here to turn light off
*/
break;
case 1:
default:
/*
* Fill in code here to turn light on
*/
break;
}
return retval;
}
static int hardware_test(struct hotplug_slot *hotplug_slot, u32 value)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
switch (value) {
case 0:
/* Specify a test here */
break;
case 1:
/* Specify another test here */
break;
}
return retval;
}
static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in logic to get the current power status of the specific
* slot and store it in the *value location.
*/
return retval;
}
static int get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in logic to get the current attention status of the specific
* slot and store it in the *value location.
*/
return retval;
}
static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in logic to get the current latch status of the specific
* slot and store it in the *value location.
*/
return retval;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
int retval = 0;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
/*
* Fill in logic to get the current adapter status of the specific
* slot and store it in the *value location.
*/
return retval;
}
static void release_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
kfree(slot->hotplug_slot->info);
kfree(slot->hotplug_slot);
kfree(slot);
}
static void make_slot_name(struct slot *slot)
{
/*
* Stupid way to make a filename out of the slot name.
* replace this if your hardware provides a better way to name slots.
*/
snprintf(slot->hotplug_slot->name, SLOT_NAME_SIZE, "%d", slot->number);
}
/**
* init_slots - initialize 'struct slot' structures for each slot
*
*/
static int __init init_slots(void)
{
struct slot *slot;
struct hotplug_slot *hotplug_slot;
struct hotplug_slot_info *info;
int retval;
int i;
/*
* Create a structure for each slot, and register that slot
* with the pci_hotplug subsystem.
*/
for (i = 0; i < num_slots; ++i) {
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot) {
retval = -ENOMEM;
goto error;
}
hotplug_slot = kzalloc(sizeof(*hotplug_slot), GFP_KERNEL);
if (!hotplug_slot) {
retval = -ENOMEM;
goto error_slot;
}
slot->hotplug_slot = hotplug_slot;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
retval = -ENOMEM;
goto error_hpslot;
}
hotplug_slot->info = info;
slot->number = i;
hotplug_slot->name = slot->name;
hotplug_slot->private = slot;
hotplug_slot->release = &release_slot;
make_slot_name(slot);
hotplug_slot->ops = &skel_hotplug_slot_ops;
/*
* Initialize the slot info structure with some known
* good values.
*/
get_power_status(hotplug_slot, &info->power_status);
get_attention_status(hotplug_slot, &info->attention_status);
get_latch_status(hotplug_slot, &info->latch_status);
get_adapter_status(hotplug_slot, &info->adapter_status);
dbg("registering slot %d\n", i);
retval = pci_hp_register(slot->hotplug_slot);
if (retval) {
err("pci_hp_register failed with error %d\n", retval);
goto error_info;
}
/* add slot to our internal list */
list_add(&slot->slot_list, &slot_list);
}
return 0;
error_info:
kfree(info);
error_hpslot:
kfree(hotplug_slot);
error_slot:
kfree(slot);
error:
return retval;
}
static void __exit cleanup_slots(void)
{
struct list_head *tmp;
struct list_head *next;
struct slot *slot;
/*
* Unregister all of our slots with the pci_hotplug subsystem.
* Memory will be freed in release_slot() callback after slot's
* lifespan is finished.
*/
list_for_each_safe(tmp, next, &slot_list) {
slot = list_entry(tmp, struct slot, slot_list);
list_del(&slot->slot_list);
pci_hp_deregister(slot->hotplug_slot);
}
}
static int __init pcihp_skel_init(void)
{
int retval;
info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
/*
* Do specific initialization stuff for your driver here
* like initializing your controller hardware (if any) and
* determining the number of slots you have in the system
* right now.
*/
num_slots = 5;
return init_slots();
}
static void __exit pcihp_skel_exit(void)
{
/*
* Clean everything up.
*/
cleanup_slots();
}
module_init(pcihp_skel_init);
module_exit(pcihp_skel_exit);
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