kernel-ark/drivers/scsi/hosts.c
James Bottomley 9e70592fcd [SCSI] fix potential panic with proc on module removal
There's a problem in our host release in that it calls
scsi_proc_hostdir_rm(). However, if you hold a reference to the host as
you remove the module, the host template (which proc uses) will be freed
and the system will panic when the host device is finally released.

Fix this by moving scsi_proc_hostdir_rm() to where it should be: in
scsi_remove_host().

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-10-02 15:20:03 -05:00

544 lines
13 KiB
C

/*
* hosts.c Copyright (C) 1992 Drew Eckhardt
* Copyright (C) 1993, 1994, 1995 Eric Youngdale
* Copyright (C) 2002-2003 Christoph Hellwig
*
* mid to lowlevel SCSI driver interface
* Initial versions: Drew Eckhardt
* Subsequent revisions: Eric Youngdale
*
* <drew@colorado.edu>
*
* Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
* Added QLOGIC QLA1280 SCSI controller kernel host support.
* August 4, 1999 Fred Lewis, Intel DuPont
*
* Updated to reflect the new initialization scheme for the higher
* level of scsi drivers (sd/sr/st)
* September 17, 2000 Torben Mathiasen <tmm@image.dk>
*
* Restructured scsi_host lists and associated functions.
* September 04, 2002 Mike Anderson (andmike@us.ibm.com)
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/transport_class.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
static int scsi_host_next_hn; /* host_no for next new host */
static void scsi_host_cls_release(struct class_device *class_dev)
{
put_device(&class_to_shost(class_dev)->shost_gendev);
}
static struct class shost_class = {
.name = "scsi_host",
.release = scsi_host_cls_release,
};
/**
* scsi_host_set_state - Take the given host through the host
* state model.
* @shost: scsi host to change the state of.
* @state: state to change to.
*
* Returns zero if unsuccessful or an error if the requested
* transition is illegal.
**/
int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
{
enum scsi_host_state oldstate = shost->shost_state;
if (state == oldstate)
return 0;
switch (state) {
case SHOST_CREATED:
/* There are no legal states that come back to
* created. This is the manually initialised start
* state */
goto illegal;
case SHOST_RUNNING:
switch (oldstate) {
case SHOST_CREATED:
case SHOST_RECOVERY:
break;
default:
goto illegal;
}
break;
case SHOST_RECOVERY:
switch (oldstate) {
case SHOST_RUNNING:
break;
default:
goto illegal;
}
break;
case SHOST_CANCEL:
switch (oldstate) {
case SHOST_CREATED:
case SHOST_RUNNING:
case SHOST_CANCEL_RECOVERY:
break;
default:
goto illegal;
}
break;
case SHOST_DEL:
switch (oldstate) {
case SHOST_CANCEL:
case SHOST_DEL_RECOVERY:
break;
default:
goto illegal;
}
break;
case SHOST_CANCEL_RECOVERY:
switch (oldstate) {
case SHOST_CANCEL:
case SHOST_RECOVERY:
break;
default:
goto illegal;
}
break;
case SHOST_DEL_RECOVERY:
switch (oldstate) {
case SHOST_CANCEL_RECOVERY:
break;
default:
goto illegal;
}
break;
}
shost->shost_state = state;
return 0;
illegal:
SCSI_LOG_ERROR_RECOVERY(1,
dev_printk(KERN_ERR, &shost->shost_gendev,
"Illegal host state transition"
"%s->%s\n",
scsi_host_state_name(oldstate),
scsi_host_state_name(state)));
return -EINVAL;
}
EXPORT_SYMBOL(scsi_host_set_state);
/**
* scsi_remove_host - remove a scsi host
* @shost: a pointer to a scsi host to remove
**/
void scsi_remove_host(struct Scsi_Host *shost)
{
unsigned long flags;
down(&shost->scan_mutex);
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_set_state(shost, SHOST_CANCEL))
if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
spin_unlock_irqrestore(shost->host_lock, flags);
up(&shost->scan_mutex);
return;
}
spin_unlock_irqrestore(shost->host_lock, flags);
up(&shost->scan_mutex);
scsi_forget_host(shost);
scsi_proc_host_rm(shost);
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_set_state(shost, SHOST_DEL))
BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
spin_unlock_irqrestore(shost->host_lock, flags);
transport_unregister_device(&shost->shost_gendev);
class_device_unregister(&shost->shost_classdev);
device_del(&shost->shost_gendev);
scsi_proc_hostdir_rm(shost->hostt);
}
EXPORT_SYMBOL(scsi_remove_host);
/**
* scsi_add_host - add a scsi host
* @shost: scsi host pointer to add
* @dev: a struct device of type scsi class
*
* Return value:
* 0 on success / != 0 for error
**/
int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
{
struct scsi_host_template *sht = shost->hostt;
int error = -EINVAL;
printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
sht->info ? sht->info(shost) : sht->name);
if (!shost->can_queue) {
printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
sht->name);
goto out;
}
if (!shost->shost_gendev.parent)
shost->shost_gendev.parent = dev ? dev : &platform_bus;
error = device_add(&shost->shost_gendev);
if (error)
goto out;
scsi_host_set_state(shost, SHOST_RUNNING);
get_device(shost->shost_gendev.parent);
error = class_device_add(&shost->shost_classdev);
if (error)
goto out_del_gendev;
get_device(&shost->shost_gendev);
if (shost->transportt->host_size &&
(shost->shost_data = kmalloc(shost->transportt->host_size,
GFP_KERNEL)) == NULL)
goto out_del_classdev;
if (shost->transportt->create_work_queue) {
snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
shost->host_no);
shost->work_q = create_singlethread_workqueue(
shost->work_q_name);
if (!shost->work_q)
goto out_free_shost_data;
}
error = scsi_sysfs_add_host(shost);
if (error)
goto out_destroy_host;
scsi_proc_host_add(shost);
return error;
out_destroy_host:
if (shost->work_q)
destroy_workqueue(shost->work_q);
out_free_shost_data:
kfree(shost->shost_data);
out_del_classdev:
class_device_del(&shost->shost_classdev);
out_del_gendev:
device_del(&shost->shost_gendev);
out:
return error;
}
EXPORT_SYMBOL(scsi_add_host);
static void scsi_host_dev_release(struct device *dev)
{
struct Scsi_Host *shost = dev_to_shost(dev);
struct device *parent = dev->parent;
if (shost->ehandler)
kthread_stop(shost->ehandler);
if (shost->work_q)
destroy_workqueue(shost->work_q);
scsi_destroy_command_freelist(shost);
kfree(shost->shost_data);
if (parent)
put_device(parent);
kfree(shost);
}
/**
* scsi_host_alloc - register a scsi host adapter instance.
* @sht: pointer to scsi host template
* @privsize: extra bytes to allocate for driver
*
* Note:
* Allocate a new Scsi_Host and perform basic initialization.
* The host is not published to the scsi midlayer until scsi_add_host
* is called.
*
* Return value:
* Pointer to a new Scsi_Host
**/
struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost;
int gfp_mask = GFP_KERNEL, rval;
if (sht->unchecked_isa_dma && privsize)
gfp_mask |= __GFP_DMA;
/* Check to see if this host has any error handling facilities */
if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
!sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
!sht->eh_host_reset_handler) {
printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
"ERROR: This is not a safe way to run your "
"SCSI host\n"
"ERROR: The error handling must be added to "
"this driver\n", sht->proc_name);
dump_stack();
}
shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
if (!shost)
return NULL;
memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
spin_lock_init(&shost->default_lock);
scsi_assign_lock(shost, &shost->default_lock);
shost->shost_state = SHOST_CREATED;
INIT_LIST_HEAD(&shost->__devices);
INIT_LIST_HEAD(&shost->__targets);
INIT_LIST_HEAD(&shost->eh_cmd_q);
INIT_LIST_HEAD(&shost->starved_list);
init_waitqueue_head(&shost->host_wait);
init_MUTEX(&shost->scan_mutex);
shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
shost->dma_channel = 0xff;
/* These three are default values which can be overridden */
shost->max_channel = 0;
shost->max_id = 8;
shost->max_lun = 8;
/* Give each shost a default transportt */
shost->transportt = &blank_transport_template;
/*
* All drivers right now should be able to handle 12 byte
* commands. Every so often there are requests for 16 byte
* commands, but individual low-level drivers need to certify that
* they actually do something sensible with such commands.
*/
shost->max_cmd_len = 12;
shost->hostt = sht;
shost->this_id = sht->this_id;
shost->can_queue = sht->can_queue;
shost->sg_tablesize = sht->sg_tablesize;
shost->cmd_per_lun = sht->cmd_per_lun;
shost->unchecked_isa_dma = sht->unchecked_isa_dma;
shost->use_clustering = sht->use_clustering;
shost->ordered_flush = sht->ordered_flush;
shost->ordered_tag = sht->ordered_tag;
/*
* hosts/devices that do queueing must support ordered tags
*/
if (shost->can_queue > 1 && shost->ordered_flush) {
printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
shost->ordered_flush = 0;
}
if (sht->max_host_blocked)
shost->max_host_blocked = sht->max_host_blocked;
else
shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
/*
* If the driver imposes no hard sector transfer limit, start at
* machine infinity initially.
*/
if (sht->max_sectors)
shost->max_sectors = sht->max_sectors;
else
shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
/*
* assume a 4GB boundary, if not set
*/
if (sht->dma_boundary)
shost->dma_boundary = sht->dma_boundary;
else
shost->dma_boundary = 0xffffffff;
rval = scsi_setup_command_freelist(shost);
if (rval)
goto fail_kfree;
device_initialize(&shost->shost_gendev);
snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
shost->host_no);
shost->shost_gendev.release = scsi_host_dev_release;
class_device_initialize(&shost->shost_classdev);
shost->shost_classdev.dev = &shost->shost_gendev;
shost->shost_classdev.class = &shost_class;
snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
shost->host_no);
shost->ehandler = kthread_run(scsi_error_handler, shost,
"scsi_eh_%d", shost->host_no);
if (IS_ERR(shost->ehandler)) {
rval = PTR_ERR(shost->ehandler);
goto fail_destroy_freelist;
}
scsi_proc_hostdir_add(shost->hostt);
return shost;
fail_destroy_freelist:
scsi_destroy_command_freelist(shost);
fail_kfree:
kfree(shost);
return NULL;
}
EXPORT_SYMBOL(scsi_host_alloc);
struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
if (!sht->detect) {
printk(KERN_WARNING "scsi_register() called on new-style "
"template for driver %s\n", sht->name);
dump_stack();
}
if (shost)
list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
return shost;
}
EXPORT_SYMBOL(scsi_register);
void scsi_unregister(struct Scsi_Host *shost)
{
list_del(&shost->sht_legacy_list);
scsi_host_put(shost);
}
EXPORT_SYMBOL(scsi_unregister);
/**
* scsi_host_lookup - get a reference to a Scsi_Host by host no
*
* @hostnum: host number to locate
*
* Return value:
* A pointer to located Scsi_Host or NULL.
**/
struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
struct class *class = &shost_class;
struct class_device *cdev;
struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
down_read(&class->subsys.rwsem);
list_for_each_entry(cdev, &class->children, node) {
p = class_to_shost(cdev);
if (p->host_no == hostnum) {
shost = scsi_host_get(p);
break;
}
}
up_read(&class->subsys.rwsem);
return shost;
}
EXPORT_SYMBOL(scsi_host_lookup);
/**
* scsi_host_get - inc a Scsi_Host ref count
* @shost: Pointer to Scsi_Host to inc.
**/
struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
{
if ((shost->shost_state == SHOST_DEL) ||
!get_device(&shost->shost_gendev))
return NULL;
return shost;
}
EXPORT_SYMBOL(scsi_host_get);
/**
* scsi_host_put - dec a Scsi_Host ref count
* @shost: Pointer to Scsi_Host to dec.
**/
void scsi_host_put(struct Scsi_Host *shost)
{
put_device(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_host_put);
int scsi_init_hosts(void)
{
return class_register(&shost_class);
}
void scsi_exit_hosts(void)
{
class_unregister(&shost_class);
}
int scsi_is_host_device(const struct device *dev)
{
return dev->release == scsi_host_dev_release;
}
EXPORT_SYMBOL(scsi_is_host_device);
/**
* scsi_queue_work - Queue work to the Scsi_Host workqueue.
* @shost: Pointer to Scsi_Host.
* @work: Work to queue for execution.
*
* Return value:
* 0 on success / != 0 for error
**/
int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
{
if (unlikely(!shost->work_q)) {
printk(KERN_ERR
"ERROR: Scsi host '%s' attempted to queue scsi-work, "
"when no workqueue created.\n", shost->hostt->name);
dump_stack();
return -EINVAL;
}
return queue_work(shost->work_q, work);
}
EXPORT_SYMBOL_GPL(scsi_queue_work);
/**
* scsi_flush_work - Flush a Scsi_Host's workqueue.
* @shost: Pointer to Scsi_Host.
**/
void scsi_flush_work(struct Scsi_Host *shost)
{
if (!shost->work_q) {
printk(KERN_ERR
"ERROR: Scsi host '%s' attempted to flush scsi-work, "
"when no workqueue created.\n", shost->hostt->name);
dump_stack();
return;
}
flush_workqueue(shost->work_q);
}
EXPORT_SYMBOL_GPL(scsi_flush_work);