linux-stable/drivers/misc/enclosure.c
James Bottomley 11e52a699a enclosure: fix WARN_ON removing an adapter in multi-path devices
We have peculiar problems with multi-path and enclosures: physically, we know
each bay can only be occupied by a single disk device.  However in multi-path,
it appears we have many (because each path to the device appears in Linux as a
different kernel device).  We try to fix this by only having the last seen
device show up in the bay.

Sysfs gets very annoyed if we try to manipulate links when the kobject sysfs
directory (kobj.sd) doesn't exist and drops a huge WARN_ON which most users
panic and report an oops for.  This happens on a few path removal situations
and IBM reports seeing it when one of their multi-path adapters is removed.

Add a check to enclosure device removal for the existence the sysfs directory
containing both the forward and back links so that the remnants (if any) get
removed in either direction but no scary warnings are dumped.

Reported-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Tested-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2015-03-31 08:53:36 +03:00

691 lines
19 KiB
C

/*
* Enclosure Services
*
* Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
*
**-----------------------------------------------------------------------------
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License
** version 2 as published by the Free Software Foundation.
**
** 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. 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.
**
**-----------------------------------------------------------------------------
*/
#include <linux/device.h>
#include <linux/enclosure.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
static LIST_HEAD(container_list);
static DEFINE_MUTEX(container_list_lock);
static struct class enclosure_class;
/**
* enclosure_find - find an enclosure given a parent device
* @dev: the parent to match against
* @start: Optional enclosure device to start from (NULL if none)
*
* Looks through the list of registered enclosures to find all those
* with @dev as a parent. Returns NULL if no enclosure is
* found. @start can be used as a starting point to obtain multiple
* enclosures per parent (should begin with NULL and then be set to
* each returned enclosure device). Obtains a reference to the
* enclosure class device which must be released with device_put().
* If @start is not NULL, a reference must be taken on it which is
* released before returning (this allows a loop through all
* enclosures to exit with only the reference on the enclosure of
* interest held). Note that the @dev may correspond to the actual
* device housing the enclosure, in which case no iteration via @start
* is required.
*/
struct enclosure_device *enclosure_find(struct device *dev,
struct enclosure_device *start)
{
struct enclosure_device *edev;
mutex_lock(&container_list_lock);
edev = list_prepare_entry(start, &container_list, node);
if (start)
put_device(&start->edev);
list_for_each_entry_continue(edev, &container_list, node) {
struct device *parent = edev->edev.parent;
/* parent might not be immediate, so iterate up to
* the root of the tree if necessary */
while (parent) {
if (parent == dev) {
get_device(&edev->edev);
mutex_unlock(&container_list_lock);
return edev;
}
parent = parent->parent;
}
}
mutex_unlock(&container_list_lock);
return NULL;
}
EXPORT_SYMBOL_GPL(enclosure_find);
/**
* enclosure_for_each_device - calls a function for each enclosure
* @fn: the function to call
* @data: the data to pass to each call
*
* Loops over all the enclosures calling the function.
*
* Note, this function uses a mutex which will be held across calls to
* @fn, so it must have non atomic context, and @fn may (although it
* should not) sleep or otherwise cause the mutex to be held for
* indefinite periods
*/
int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
void *data)
{
int error = 0;
struct enclosure_device *edev;
mutex_lock(&container_list_lock);
list_for_each_entry(edev, &container_list, node) {
error = fn(edev, data);
if (error)
break;
}
mutex_unlock(&container_list_lock);
return error;
}
EXPORT_SYMBOL_GPL(enclosure_for_each_device);
/**
* enclosure_register - register device as an enclosure
*
* @dev: device containing the enclosure
* @components: number of components in the enclosure
*
* This sets up the device for being an enclosure. Note that @dev does
* not have to be a dedicated enclosure device. It may be some other type
* of device that additionally responds to enclosure services
*/
struct enclosure_device *
enclosure_register(struct device *dev, const char *name, int components,
struct enclosure_component_callbacks *cb)
{
struct enclosure_device *edev =
kzalloc(sizeof(struct enclosure_device) +
sizeof(struct enclosure_component)*components,
GFP_KERNEL);
int err, i;
BUG_ON(!cb);
if (!edev)
return ERR_PTR(-ENOMEM);
edev->components = components;
edev->edev.class = &enclosure_class;
edev->edev.parent = get_device(dev);
edev->cb = cb;
dev_set_name(&edev->edev, "%s", name);
err = device_register(&edev->edev);
if (err)
goto err;
for (i = 0; i < components; i++) {
edev->component[i].number = -1;
edev->component[i].slot = -1;
edev->component[i].power_status = 1;
}
mutex_lock(&container_list_lock);
list_add_tail(&edev->node, &container_list);
mutex_unlock(&container_list_lock);
return edev;
err:
put_device(edev->edev.parent);
kfree(edev);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(enclosure_register);
static struct enclosure_component_callbacks enclosure_null_callbacks;
/**
* enclosure_unregister - remove an enclosure
*
* @edev: the registered enclosure to remove;
*/
void enclosure_unregister(struct enclosure_device *edev)
{
int i;
mutex_lock(&container_list_lock);
list_del(&edev->node);
mutex_unlock(&container_list_lock);
for (i = 0; i < edev->components; i++)
if (edev->component[i].number != -1)
device_unregister(&edev->component[i].cdev);
/* prevent any callbacks into service user */
edev->cb = &enclosure_null_callbacks;
device_unregister(&edev->edev);
}
EXPORT_SYMBOL_GPL(enclosure_unregister);
#define ENCLOSURE_NAME_SIZE 64
#define COMPONENT_NAME_SIZE 64
static void enclosure_link_name(struct enclosure_component *cdev, char *name)
{
strcpy(name, "enclosure_device:");
strcat(name, dev_name(&cdev->cdev));
}
static void enclosure_remove_links(struct enclosure_component *cdev)
{
char name[ENCLOSURE_NAME_SIZE];
enclosure_link_name(cdev, name);
/*
* In odd circumstances, like multipath devices, something else may
* already have removed the links, so check for this condition first.
*/
if (cdev->dev->kobj.sd)
sysfs_remove_link(&cdev->dev->kobj, name);
if (cdev->cdev.kobj.sd)
sysfs_remove_link(&cdev->cdev.kobj, "device");
}
static int enclosure_add_links(struct enclosure_component *cdev)
{
int error;
char name[ENCLOSURE_NAME_SIZE];
error = sysfs_create_link(&cdev->cdev.kobj, &cdev->dev->kobj, "device");
if (error)
return error;
enclosure_link_name(cdev, name);
error = sysfs_create_link(&cdev->dev->kobj, &cdev->cdev.kobj, name);
if (error)
sysfs_remove_link(&cdev->cdev.kobj, "device");
return error;
}
static void enclosure_release(struct device *cdev)
{
struct enclosure_device *edev = to_enclosure_device(cdev);
put_device(cdev->parent);
kfree(edev);
}
static void enclosure_component_release(struct device *dev)
{
struct enclosure_component *cdev = to_enclosure_component(dev);
if (cdev->dev) {
enclosure_remove_links(cdev);
put_device(cdev->dev);
}
put_device(dev->parent);
}
static struct enclosure_component *
enclosure_component_find_by_name(struct enclosure_device *edev,
const char *name)
{
int i;
const char *cname;
struct enclosure_component *ecomp;
if (!edev || !name || !name[0])
return NULL;
for (i = 0; i < edev->components; i++) {
ecomp = &edev->component[i];
cname = dev_name(&ecomp->cdev);
if (ecomp->number != -1 &&
cname && cname[0] &&
!strcmp(cname, name))
return ecomp;
}
return NULL;
}
static const struct attribute_group *enclosure_component_groups[];
/**
* enclosure_component_alloc - prepare a new enclosure component
* @edev: the enclosure to add the component
* @num: the device number
* @type: the type of component being added
* @name: an optional name to appear in sysfs (leave NULL if none)
*
* The name is optional for enclosures that give their components a unique
* name. If not, leave the field NULL and a name will be assigned.
*
* Returns a pointer to the enclosure component or an error.
*/
struct enclosure_component *
enclosure_component_alloc(struct enclosure_device *edev,
unsigned int number,
enum enclosure_component_type type,
const char *name)
{
struct enclosure_component *ecomp;
struct device *cdev;
int i;
char newname[COMPONENT_NAME_SIZE];
if (number >= edev->components)
return ERR_PTR(-EINVAL);
ecomp = &edev->component[number];
if (ecomp->number != -1)
return ERR_PTR(-EINVAL);
ecomp->type = type;
ecomp->number = number;
cdev = &ecomp->cdev;
cdev->parent = get_device(&edev->edev);
if (name && name[0]) {
/* Some hardware (e.g. enclosure in RX300 S6) has components
* with non unique names. Registering duplicates in sysfs
* will lead to warnings during bootup. So make the names
* unique by appending consecutive numbers -1, -2, ... */
i = 1;
snprintf(newname, COMPONENT_NAME_SIZE,
"%s", name);
while (enclosure_component_find_by_name(edev, newname))
snprintf(newname, COMPONENT_NAME_SIZE,
"%s-%i", name, i++);
dev_set_name(cdev, "%s", newname);
} else
dev_set_name(cdev, "%u", number);
cdev->release = enclosure_component_release;
cdev->groups = enclosure_component_groups;
return ecomp;
}
EXPORT_SYMBOL_GPL(enclosure_component_alloc);
/**
* enclosure_component_register - publishes an initialized enclosure component
* @ecomp: component to add
*
* Returns 0 on successful registration, releases the component otherwise
*/
int enclosure_component_register(struct enclosure_component *ecomp)
{
struct device *cdev;
int err;
cdev = &ecomp->cdev;
err = device_register(cdev);
if (err) {
ecomp->number = -1;
put_device(cdev);
return err;
}
return 0;
}
EXPORT_SYMBOL_GPL(enclosure_component_register);
/**
* enclosure_add_device - add a device as being part of an enclosure
* @edev: the enclosure device being added to.
* @num: the number of the component
* @dev: the device being added
*
* Declares a real device to reside in slot (or identifier) @num of an
* enclosure. This will cause the relevant sysfs links to appear.
* This function may also be used to change a device associated with
* an enclosure without having to call enclosure_remove_device() in
* between.
*
* Returns zero on success or an error.
*/
int enclosure_add_device(struct enclosure_device *edev, int component,
struct device *dev)
{
struct enclosure_component *cdev;
if (!edev || component >= edev->components)
return -EINVAL;
cdev = &edev->component[component];
if (cdev->dev == dev)
return -EEXIST;
if (cdev->dev)
enclosure_remove_links(cdev);
put_device(cdev->dev);
cdev->dev = get_device(dev);
return enclosure_add_links(cdev);
}
EXPORT_SYMBOL_GPL(enclosure_add_device);
/**
* enclosure_remove_device - remove a device from an enclosure
* @edev: the enclosure device
* @num: the number of the component to remove
*
* Returns zero on success or an error.
*
*/
int enclosure_remove_device(struct enclosure_device *edev, struct device *dev)
{
struct enclosure_component *cdev;
int i;
if (!edev || !dev)
return -EINVAL;
for (i = 0; i < edev->components; i++) {
cdev = &edev->component[i];
if (cdev->dev == dev) {
enclosure_remove_links(cdev);
device_del(&cdev->cdev);
put_device(dev);
cdev->dev = NULL;
return device_add(&cdev->cdev);
}
}
return -ENODEV;
}
EXPORT_SYMBOL_GPL(enclosure_remove_device);
/*
* sysfs pieces below
*/
static ssize_t components_show(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev);
return snprintf(buf, 40, "%d\n", edev->components);
}
static DEVICE_ATTR_RO(components);
static ssize_t id_show(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev);
if (edev->cb->show_id)
return edev->cb->show_id(edev, buf);
return -EINVAL;
}
static DEVICE_ATTR_RO(id);
static struct attribute *enclosure_class_attrs[] = {
&dev_attr_components.attr,
&dev_attr_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(enclosure_class);
static struct class enclosure_class = {
.name = "enclosure",
.owner = THIS_MODULE,
.dev_release = enclosure_release,
.dev_groups = enclosure_class_groups,
};
static const char *const enclosure_status [] = {
[ENCLOSURE_STATUS_UNSUPPORTED] = "unsupported",
[ENCLOSURE_STATUS_OK] = "OK",
[ENCLOSURE_STATUS_CRITICAL] = "critical",
[ENCLOSURE_STATUS_NON_CRITICAL] = "non-critical",
[ENCLOSURE_STATUS_UNRECOVERABLE] = "unrecoverable",
[ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
[ENCLOSURE_STATUS_UNKNOWN] = "unknown",
[ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
[ENCLOSURE_STATUS_MAX] = NULL,
};
static const char *const enclosure_type [] = {
[ENCLOSURE_COMPONENT_DEVICE] = "device",
[ENCLOSURE_COMPONENT_ARRAY_DEVICE] = "array device",
};
static ssize_t get_component_fault(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
if (edev->cb->get_fault)
edev->cb->get_fault(edev, ecomp);
return snprintf(buf, 40, "%d\n", ecomp->fault);
}
static ssize_t set_component_fault(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int val = simple_strtoul(buf, NULL, 0);
if (edev->cb->set_fault)
edev->cb->set_fault(edev, ecomp, val);
return count;
}
static ssize_t get_component_status(struct device *cdev,
struct device_attribute *attr,char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
if (edev->cb->get_status)
edev->cb->get_status(edev, ecomp);
return snprintf(buf, 40, "%s\n", enclosure_status[ecomp->status]);
}
static ssize_t set_component_status(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int i;
for (i = 0; enclosure_status[i]; i++) {
if (strncmp(buf, enclosure_status[i],
strlen(enclosure_status[i])) == 0 &&
(buf[strlen(enclosure_status[i])] == '\n' ||
buf[strlen(enclosure_status[i])] == '\0'))
break;
}
if (enclosure_status[i] && edev->cb->set_status) {
edev->cb->set_status(edev, ecomp, i);
return count;
} else
return -EINVAL;
}
static ssize_t get_component_active(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
if (edev->cb->get_active)
edev->cb->get_active(edev, ecomp);
return snprintf(buf, 40, "%d\n", ecomp->active);
}
static ssize_t set_component_active(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int val = simple_strtoul(buf, NULL, 0);
if (edev->cb->set_active)
edev->cb->set_active(edev, ecomp, val);
return count;
}
static ssize_t get_component_locate(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
if (edev->cb->get_locate)
edev->cb->get_locate(edev, ecomp);
return snprintf(buf, 40, "%d\n", ecomp->locate);
}
static ssize_t set_component_locate(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int val = simple_strtoul(buf, NULL, 0);
if (edev->cb->set_locate)
edev->cb->set_locate(edev, ecomp, val);
return count;
}
static ssize_t get_component_power_status(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
if (edev->cb->get_power_status)
edev->cb->get_power_status(edev, ecomp);
return snprintf(buf, 40, "%s\n", ecomp->power_status ? "on" : "off");
}
static ssize_t set_component_power_status(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct enclosure_device *edev = to_enclosure_device(cdev->parent);
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int val;
if (strncmp(buf, "on", 2) == 0 &&
(buf[2] == '\n' || buf[2] == '\0'))
val = 1;
else if (strncmp(buf, "off", 3) == 0 &&
(buf[3] == '\n' || buf[3] == '\0'))
val = 0;
else
return -EINVAL;
if (edev->cb->set_power_status)
edev->cb->set_power_status(edev, ecomp, val);
return count;
}
static ssize_t get_component_type(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_component *ecomp = to_enclosure_component(cdev);
return snprintf(buf, 40, "%s\n", enclosure_type[ecomp->type]);
}
static ssize_t get_component_slot(struct device *cdev,
struct device_attribute *attr, char *buf)
{
struct enclosure_component *ecomp = to_enclosure_component(cdev);
int slot;
/* if the enclosure does not override then use 'number' as a stand-in */
if (ecomp->slot >= 0)
slot = ecomp->slot;
else
slot = ecomp->number;
return snprintf(buf, 40, "%d\n", slot);
}
static DEVICE_ATTR(fault, S_IRUGO | S_IWUSR, get_component_fault,
set_component_fault);
static DEVICE_ATTR(status, S_IRUGO | S_IWUSR, get_component_status,
set_component_status);
static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, get_component_active,
set_component_active);
static DEVICE_ATTR(locate, S_IRUGO | S_IWUSR, get_component_locate,
set_component_locate);
static DEVICE_ATTR(power_status, S_IRUGO | S_IWUSR, get_component_power_status,
set_component_power_status);
static DEVICE_ATTR(type, S_IRUGO, get_component_type, NULL);
static DEVICE_ATTR(slot, S_IRUGO, get_component_slot, NULL);
static struct attribute *enclosure_component_attrs[] = {
&dev_attr_fault.attr,
&dev_attr_status.attr,
&dev_attr_active.attr,
&dev_attr_locate.attr,
&dev_attr_power_status.attr,
&dev_attr_type.attr,
&dev_attr_slot.attr,
NULL
};
ATTRIBUTE_GROUPS(enclosure_component);
static int __init enclosure_init(void)
{
int err;
err = class_register(&enclosure_class);
if (err)
return err;
return 0;
}
static void __exit enclosure_exit(void)
{
class_unregister(&enclosure_class);
}
module_init(enclosure_init);
module_exit(enclosure_exit);
MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("Enclosure Services");
MODULE_LICENSE("GPL v2");