/*
* 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 <linux/slab.h>
#include <linux/module.h>
#include <scsi/scsi_dh.h>
#include "scsi_priv.h"
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(scsi_dh_list);
struct scsi_dh_blist {
const char *vendor;
const char *model;
const char *driver;
};
static const struct scsi_dh_blist scsi_dh_blist[] = {
{"DGC", "RAID", "emc" },
{"DGC", "DISK", "emc" },
{"DGC", "VRAID", "emc" },
{"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
{"COMPAQ", "HSV110", "hp_sw" },
{"HP", "HSV100", "hp_sw"},
{"DEC", "HSG80", "hp_sw"},
{"IBM", "1722", "rdac", },
{"IBM", "1724", "rdac", },
{"IBM", "1726", "rdac", },
{"IBM", "1742", "rdac", },
{"IBM", "1745", "rdac", },
{"IBM", "1746", "rdac", },
{"IBM", "1813", "rdac", },
{"IBM", "1814", "rdac", },
{"IBM", "1815", "rdac", },
{"IBM", "1818", "rdac", },
{"IBM", "3526", "rdac", },
{"SGI", "TP9", "rdac", },
{"SGI", "IS", "rdac", },
{"STK", "OPENstorage D280", "rdac", },
{"STK", "FLEXLINE 380", "rdac", },
{"SUN", "CSM", "rdac", },
{"SUN", "LCSM100", "rdac", },
{"SUN", "STK6580_6780", "rdac", },
{"SUN", "SUN_6180", "rdac", },
{"SUN", "ArrayStorage", "rdac", },
{"DELL", "MD3", "rdac", },
{"NETAPP", "INF-01-00", "rdac", },
{"LSI", "INF-01-00", "rdac", },
{"ENGENIO", "INF-01-00", "rdac", },
{NULL, NULL, NULL },
};
static const char *
scsi_dh_find_driver(struct scsi_device *sdev)
{
const struct scsi_dh_blist *b;
if (scsi_device_tpgs(sdev))
return "alua";
for (b = scsi_dh_blist; b->vendor; b++) {
if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
!strncmp(sdev->model, b->model, strlen(b->model))) {
return b->driver;
}
}
return NULL;
}
static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
{
struct scsi_device_handler *tmp, *found = NULL;
spin_lock(&list_lock);
list_for_each_entry(tmp, &scsi_dh_list, list) {
if (!strncmp(tmp->name, name, strlen(tmp->name))) {
found = tmp;
break;
}
}
spin_unlock(&list_lock);
return found;
}
static struct scsi_device_handler *scsi_dh_lookup(const char *name)
{
struct scsi_device_handler *dh;
dh = __scsi_dh_lookup(name);
if (!dh) {
request_module("scsi_dh_%s", name);
dh = __scsi_dh_lookup(name);
}
return dh;
}
/*
* scsi_dh_handler_attach - Attach a device handler to a device
* @sdev - SCSI device the device handler should attach to
* @scsi_dh - The device handler to attach
*/
static int scsi_dh_handler_attach(struct scsi_device *sdev,
struct scsi_device_handler *scsi_dh)
{
int error, ret = 0;
if (!try_module_get(scsi_dh->module))
return -EINVAL;
error = scsi_dh->attach(sdev);
if (error != SCSI_DH_OK) {
switch (error) {
case SCSI_DH_NOMEM:
ret = -ENOMEM;
break;
case SCSI_DH_RES_TEMP_UNAVAIL:
ret = -EAGAIN;
break;
case SCSI_DH_DEV_UNSUPP:
case SCSI_DH_NOSYS:
ret = -ENODEV;
break;
default:
ret = -EINVAL;
break;
}
if (ret != -ENODEV)
sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
scsi_dh->name, error);
module_put(scsi_dh->module);
} else
sdev->handler = scsi_dh;
return ret;
}
/*
* scsi_dh_handler_detach - Detach a device handler from a device
* @sdev - SCSI device the device handler should be detached from
*/
static void scsi_dh_handler_detach(struct scsi_device *sdev)
{
sdev->handler->detach(sdev);
sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
module_put(sdev->handler->module);
}
void scsi_dh_add_device(struct scsi_device *sdev)
{
struct scsi_device_handler *devinfo = NULL;
const char *drv;
drv = scsi_dh_find_driver(sdev);
if (drv)
devinfo = __scsi_dh_lookup(drv);
/*
* device_handler is optional, so ignore errors
* from scsi_dh_handler_attach()
*/
if (devinfo)
(void)scsi_dh_handler_attach(sdev, devinfo);
}
void scsi_dh_release_device(struct scsi_device *sdev)
{
if (sdev->handler)
scsi_dh_handler_detach(sdev);
}
/*
* 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)
{
if (__scsi_dh_lookup(scsi_dh->name))
return -EBUSY;
if (!scsi_dh->attach || !scsi_dh->detach)
return -EINVAL;
spin_lock(&list_lock);
list_add(&scsi_dh->list, &scsi_dh_list);
spin_unlock(&list_lock);
printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_register_device_handler);
/*
* 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)
{
if (!__scsi_dh_lookup(scsi_dh->name))
return -ENODEV;
spin_lock(&list_lock);
list_del(&scsi_dh->list);
spin_unlock(&list_lock);
printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
/*
* scsi_dh_activate - activate the path associated with the scsi_device
* corresponding to the given request queue.
* Returns immediately without waiting for activation to be completed.
* @q - Request queue that is associated with the scsi_device to be
* activated.
* @fn - Function to be called upon completion of the activation.
* Function fn is called with data (below) and the error code.
* Function fn may be called from the same calling context. So,
* do not hold the lock in the caller which may be needed in fn.
* @data - data passed to the function fn upon completion.
*
*/
int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
{
struct scsi_device *sdev;
int err = SCSI_DH_NOSYS;
sdev = scsi_device_from_queue(q);
if (!sdev) {
if (fn)
fn(data, err);
return err;
}
if (!sdev->handler)
goto out_fn;
err = SCSI_DH_NOTCONN;
if (sdev->sdev_state == SDEV_CANCEL ||
sdev->sdev_state == SDEV_DEL)
goto out_fn;
err = SCSI_DH_DEV_OFFLINED;
if (sdev->sdev_state == SDEV_OFFLINE)
goto out_fn;
if (sdev->handler->activate)
err = sdev->handler->activate(sdev, fn, data);
out_put_device:
put_device(&sdev->sdev_gendev);
return err;
out_fn:
if (fn)
fn(data, err);
goto out_put_device;
}
EXPORT_SYMBOL_GPL(scsi_dh_activate);
/*
* scsi_dh_set_params - set the parameters for the device as per the
* string specified in params.
* @q - Request queue that is associated with the scsi_device for
* which the parameters to be set.
* @params - parameters in the following format
* "no_of_params\0param1\0param2\0param3\0...\0"
* for example, string for 2 parameters with value 10 and 21
* is specified as "2\010\021\0".
*/
int scsi_dh_set_params(struct request_queue *q, const char *params)
{
struct scsi_device *sdev;
int err = -SCSI_DH_NOSYS;
sdev = scsi_device_from_queue(q);
if (!sdev)
return err;
if (sdev->handler && sdev->handler->set_params)
err = sdev->handler->set_params(sdev, params);
put_device(&sdev->sdev_gendev);
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_set_params);
/*
* scsi_dh_attach - Attach device handler
* @q - Request queue that is associated with the scsi_device
* the handler should be attached to
* @name - name of the handler to attach
*/
int scsi_dh_attach(struct request_queue *q, const char *name)
{
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh;
int err = 0;
sdev = scsi_device_from_queue(q);
if (!sdev)
return -ENODEV;
scsi_dh = scsi_dh_lookup(name);
if (!scsi_dh) {
err = -EINVAL;
goto out_put_device;
}
if (sdev->handler) {
if (sdev->handler != scsi_dh)
err = -EBUSY;
goto out_put_device;
}
err = scsi_dh_handler_attach(sdev, scsi_dh);
out_put_device:
put_device(&sdev->sdev_gendev);
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_attach);
/*
* scsi_dh_attached_handler_name - Get attached device handler's name
* @q - Request queue that is associated with the scsi_device
* that may have a device handler attached
* @gfp - the GFP mask used in the kmalloc() call when allocating memory
*
* Returns name of attached handler, NULL if no handler is attached.
* Caller must take care to free the returned string.
*/
const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
{
struct scsi_device *sdev;
const char *handler_name = NULL;
sdev = scsi_device_from_queue(q);
if (!sdev)
return NULL;
if (sdev->handler)
handler_name = kstrdup(sdev->handler->name, gfp);
put_device(&sdev->sdev_gendev);
return handler_name;
}
EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
