linux/drivers/scsi/raid_class.c
James Bottomley 2f3edc6936 [SCSI] transport_class: BUG if we can't release the attribute container
Every current transport class calls transport_container_release but
ignores the return value.  This is catastrophic if it returns an error
because the containers are part of a global list and the next action of
almost every transport class is to free the memory used by the
container.

Fix this by making transport_container_release a void, but making it BUG
if attribute_container_release returns an error ... this catches the
root cause of a system panic much earlier.  If we don't do this, we get
an eventual BUG when the attribute container list notices the corruption
caused by the freed memory it's still referencing.

Also made attribute_container_release __must_check as a reminder.

Cc: Greg KH <greg@kroah.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-04-07 12:19:10 -05:00

315 lines
7.7 KiB
C

/*
* raid_class.c - implementation of a simple raid visualisation class
*
* Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
*
* This file is licensed under GPLv2
*
* This class is designed to allow raid attributes to be visualised and
* manipulated in a form independent of the underlying raid. Ultimately this
* should work for both hardware and software raids.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/raid_class.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#define RAID_NUM_ATTRS 3
struct raid_internal {
struct raid_template r;
struct raid_function_template *f;
/* The actual attributes */
struct class_device_attribute private_attrs[RAID_NUM_ATTRS];
/* The array of null terminated pointers to attributes
* needed by scsi_sysfs.c */
struct class_device_attribute *attrs[RAID_NUM_ATTRS + 1];
};
struct raid_component {
struct list_head node;
struct class_device cdev;
int num;
};
#define to_raid_internal(tmpl) container_of(tmpl, struct raid_internal, r)
#define tc_to_raid_internal(tcont) ({ \
struct raid_template *r = \
container_of(tcont, struct raid_template, raid_attrs); \
to_raid_internal(r); \
})
#define ac_to_raid_internal(acont) ({ \
struct transport_container *tc = \
container_of(acont, struct transport_container, ac); \
tc_to_raid_internal(tc); \
})
#define class_device_to_raid_internal(cdev) ({ \
struct attribute_container *ac = \
attribute_container_classdev_to_container(cdev); \
ac_to_raid_internal(ac); \
})
static int raid_match(struct attribute_container *cont, struct device *dev)
{
/* We have to look for every subsystem that could house
* emulated RAID devices, so start with SCSI */
struct raid_internal *i = ac_to_raid_internal(cont);
if (scsi_is_sdev_device(dev)) {
struct scsi_device *sdev = to_scsi_device(dev);
if (i->f->cookie != sdev->host->hostt)
return 0;
return i->f->is_raid(dev);
}
/* FIXME: look at other subsystems too */
return 0;
}
static int raid_setup(struct transport_container *tc, struct device *dev,
struct class_device *cdev)
{
struct raid_data *rd;
BUG_ON(class_get_devdata(cdev));
rd = kzalloc(sizeof(*rd), GFP_KERNEL);
if (!rd)
return -ENOMEM;
INIT_LIST_HEAD(&rd->component_list);
class_set_devdata(cdev, rd);
return 0;
}
static int raid_remove(struct transport_container *tc, struct device *dev,
struct class_device *cdev)
{
struct raid_data *rd = class_get_devdata(cdev);
struct raid_component *rc, *next;
dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
class_set_devdata(cdev, NULL);
list_for_each_entry_safe(rc, next, &rd->component_list, node) {
list_del(&rc->node);
dev_printk(KERN_ERR, rc->cdev.dev, "RAID COMPONENT REMOVE\n");
class_device_unregister(&rc->cdev);
}
dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
kfree(rd);
return 0;
}
static DECLARE_TRANSPORT_CLASS(raid_class,
"raid_devices",
raid_setup,
raid_remove,
NULL);
static const struct {
enum raid_state value;
char *name;
} raid_states[] = {
{ RAID_STATE_UNKNOWN, "unknown" },
{ RAID_STATE_ACTIVE, "active" },
{ RAID_STATE_DEGRADED, "degraded" },
{ RAID_STATE_RESYNCING, "resyncing" },
{ RAID_STATE_OFFLINE, "offline" },
};
static const char *raid_state_name(enum raid_state state)
{
int i;
char *name = NULL;
for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
if (raid_states[i].value == state) {
name = raid_states[i].name;
break;
}
}
return name;
}
static struct {
enum raid_level value;
char *name;
} raid_levels[] = {
{ RAID_LEVEL_UNKNOWN, "unknown" },
{ RAID_LEVEL_LINEAR, "linear" },
{ RAID_LEVEL_0, "raid0" },
{ RAID_LEVEL_1, "raid1" },
{ RAID_LEVEL_10, "raid10" },
{ RAID_LEVEL_3, "raid3" },
{ RAID_LEVEL_4, "raid4" },
{ RAID_LEVEL_5, "raid5" },
{ RAID_LEVEL_50, "raid50" },
{ RAID_LEVEL_6, "raid6" },
};
static const char *raid_level_name(enum raid_level level)
{
int i;
char *name = NULL;
for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
if (raid_levels[i].value == level) {
name = raid_levels[i].name;
break;
}
}
return name;
}
#define raid_attr_show_internal(attr, fmt, var, code) \
static ssize_t raid_show_##attr(struct class_device *cdev, char *buf) \
{ \
struct raid_data *rd = class_get_devdata(cdev); \
code \
return snprintf(buf, 20, #fmt "\n", var); \
}
#define raid_attr_ro_states(attr, states, code) \
raid_attr_show_internal(attr, %s, name, \
const char *name; \
code \
name = raid_##states##_name(rd->attr); \
) \
static CLASS_DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
#define raid_attr_ro_internal(attr, code) \
raid_attr_show_internal(attr, %d, rd->attr, code) \
static CLASS_DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
#define ATTR_CODE(attr) \
struct raid_internal *i = class_device_to_raid_internal(cdev); \
if (i->f->get_##attr) \
i->f->get_##attr(cdev->dev);
#define raid_attr_ro(attr) raid_attr_ro_internal(attr, )
#define raid_attr_ro_fn(attr) raid_attr_ro_internal(attr, ATTR_CODE(attr))
#define raid_attr_ro_state(attr) raid_attr_ro_states(attr, attr, )
#define raid_attr_ro_state_fn(attr) raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
raid_attr_ro_state(level);
raid_attr_ro_fn(resync);
raid_attr_ro_state_fn(state);
static void raid_component_release(struct class_device *cdev)
{
struct raid_component *rc = container_of(cdev, struct raid_component,
cdev);
dev_printk(KERN_ERR, rc->cdev.dev, "COMPONENT RELEASE\n");
put_device(rc->cdev.dev);
kfree(rc);
}
int raid_component_add(struct raid_template *r,struct device *raid_dev,
struct device *component_dev)
{
struct class_device *cdev =
attribute_container_find_class_device(&r->raid_attrs.ac,
raid_dev);
struct raid_component *rc;
struct raid_data *rd = class_get_devdata(cdev);
int err;
rc = kzalloc(sizeof(*rc), GFP_KERNEL);
if (!rc)
return -ENOMEM;
INIT_LIST_HEAD(&rc->node);
class_device_initialize(&rc->cdev);
rc->cdev.release = raid_component_release;
rc->cdev.dev = get_device(component_dev);
rc->num = rd->component_count++;
snprintf(rc->cdev.class_id, sizeof(rc->cdev.class_id),
"component-%d", rc->num);
list_add_tail(&rc->node, &rd->component_list);
rc->cdev.parent = cdev;
rc->cdev.class = &raid_class.class;
err = class_device_add(&rc->cdev);
if (err)
goto err_out;
return 0;
err_out:
list_del(&rc->node);
rd->component_count--;
put_device(component_dev);
kfree(rc);
return err;
}
EXPORT_SYMBOL(raid_component_add);
struct raid_template *
raid_class_attach(struct raid_function_template *ft)
{
struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
GFP_KERNEL);
int count = 0;
if (unlikely(!i))
return NULL;
i->f = ft;
i->r.raid_attrs.ac.class = &raid_class.class;
i->r.raid_attrs.ac.match = raid_match;
i->r.raid_attrs.ac.attrs = &i->attrs[0];
attribute_container_register(&i->r.raid_attrs.ac);
i->attrs[count++] = &class_device_attr_level;
i->attrs[count++] = &class_device_attr_resync;
i->attrs[count++] = &class_device_attr_state;
i->attrs[count] = NULL;
BUG_ON(count > RAID_NUM_ATTRS);
return &i->r;
}
EXPORT_SYMBOL(raid_class_attach);
void
raid_class_release(struct raid_template *r)
{
struct raid_internal *i = to_raid_internal(r);
BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
kfree(i);
}
EXPORT_SYMBOL(raid_class_release);
static __init int raid_init(void)
{
return transport_class_register(&raid_class);
}
static __exit void raid_exit(void)
{
transport_class_unregister(&raid_class);
}
MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("RAID device class");
MODULE_LICENSE("GPL");
module_init(raid_init);
module_exit(raid_exit);