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/*
* SCSI device handler infrastruture.
*
* 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. 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.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2007
* Authors:
* Chandra Seetharaman <sekharan@us.ibm.com>
* Mike Anderson <andmike@linux.vnet.ibm.com>
*/
#include <scsi/scsi_dh.h>
#include "../scsi_priv.h"
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(scsi_dh_list);
static struct scsi_device_handler *get_device_handler(const char *name)
{
struct scsi_device_handler *tmp, *found = NULL;
spin_lock(&list_lock);
list_for_each_entry(tmp, &scsi_dh_list, list) {
if (!strcmp(tmp->name, name)) {
found = tmp;
break;
}
}
spin_unlock(&list_lock);
return found;
}
static int scsi_dh_notifier_add(struct device *dev, void *data)
{
struct scsi_device_handler *scsi_dh = data;
scsi_dh->nb.notifier_call(&scsi_dh->nb, BUS_NOTIFY_ADD_DEVICE, dev);
return 0;
}
/*
* scsi_register_device_handler - register a device handler personality
* module.
* @scsi_dh - device handler to be registered.
*
* Returns 0 on success, -EBUSY if handler already registered.
*/
int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
{
int ret = -EBUSY;
struct scsi_device_handler *tmp;
tmp = get_device_handler(scsi_dh->name);
if (tmp)
goto done;
ret = bus_register_notifier(&scsi_bus_type, &scsi_dh->nb);
bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
spin_lock(&list_lock);
list_add(&scsi_dh->list, &scsi_dh_list);
spin_unlock(&list_lock);
done:
return ret;
}
EXPORT_SYMBOL_GPL(scsi_register_device_handler);
static int scsi_dh_notifier_remove(struct device *dev, void *data)
{
struct scsi_device_handler *scsi_dh = data;
scsi_dh->nb.notifier_call(&scsi_dh->nb, BUS_NOTIFY_DEL_DEVICE, dev);
return 0;
}
/*
* scsi_unregister_device_handler - register a device handler personality
* module.
* @scsi_dh - device handler to be unregistered.
*
* Returns 0 on success, -ENODEV if handler not registered.
*/
int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
{
int ret = -ENODEV;
struct scsi_device_handler *tmp;
tmp = get_device_handler(scsi_dh->name);
if (!tmp)
goto done;
ret = bus_unregister_notifier(&scsi_bus_type, &scsi_dh->nb);
bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
scsi_dh_notifier_remove);
spin_lock(&list_lock);
list_del(&scsi_dh->list);
spin_unlock(&list_lock);
done:
return ret;
}
EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
/*
* scsi_dh_activate - activate the path associated with the scsi_device
* corresponding to the given request queue.
* @q - Request queue that is associated with the scsi_device to be
* activated.
*/
int scsi_dh_activate(struct request_queue *q)
{
int err = 0;
unsigned long flags;
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (sdev && sdev->scsi_dh_data)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (!scsi_dh || !get_device(&sdev->sdev_gendev))
err = SCSI_DH_NOSYS;
spin_unlock_irqrestore(q->queue_lock, flags);
if (err)
return err;
if (scsi_dh->activate)
err = scsi_dh->activate(sdev);
put_device(&sdev->sdev_gendev);
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_activate);
/*
* scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for
* the given name. FALSE(0) otherwise.
* @name - name of the device handler.
*/
int scsi_dh_handler_exist(const char *name)
{
return (get_device_handler(name) != NULL);
}
EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
MODULE_DESCRIPTION("SCSI device handler");
MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
MODULE_LICENSE("GPL");
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