linux/drivers/scsi/scsi_dh.c
Christoph Hellwig d6a32b9809 scsi_dh: don't try to load a device handler during async probing
Request_module gets really unhappy when called from async probing, so
revert to not auto load device handler modules during the SCSI bus
scan.  While autoloading would be really useful we never did this
until 4.3-rc and it turns out that functionality doesn't actually
work.

Fixes: 566079 ("dm-mpath, scsi_dh: request scsi_dh modules in scsi_dh, not dm-mpath")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Paul Mackerras <paulus@ozlabs.org>
Tested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-10-27 15:03:31 +09:00

442 lines
11 KiB
C

/*
* 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", "clariion" },
{"DGC", "DISK", "clariion" },
{"DGC", "VRAID", "clariion" },
{"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;
if (!try_module_get(scsi_dh->module))
return -EINVAL;
error = scsi_dh->attach(sdev);
if (error) {
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 error;
}
/*
* 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);
}
/*
* Functions for sysfs attribute 'dh_state'
*/
static ssize_t
store_dh_state(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct scsi_device *sdev = to_scsi_device(dev);
struct scsi_device_handler *scsi_dh;
int err = -EINVAL;
if (sdev->sdev_state == SDEV_CANCEL ||
sdev->sdev_state == SDEV_DEL)
return -ENODEV;
if (!sdev->handler) {
/*
* Attach to a device handler
*/
scsi_dh = scsi_dh_lookup(buf);
if (!scsi_dh)
return err;
err = scsi_dh_handler_attach(sdev, scsi_dh);
} else {
if (!strncmp(buf, "detach", 6)) {
/*
* Detach from a device handler
*/
sdev_printk(KERN_WARNING, sdev,
"can't detach handler %s.\n",
sdev->handler->name);
err = -EINVAL;
} else if (!strncmp(buf, "activate", 8)) {
/*
* Activate a device handler
*/
if (sdev->handler->activate)
err = sdev->handler->activate(sdev, NULL, NULL);
else
err = 0;
}
}
return err<0?err:count;
}
static ssize_t
show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_device *sdev = to_scsi_device(dev);
if (!sdev->handler)
return snprintf(buf, 20, "detached\n");
return snprintf(buf, 20, "%s\n", sdev->handler->name);
}
static struct device_attribute scsi_dh_state_attr =
__ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
store_dh_state);
int scsi_dh_add_device(struct scsi_device *sdev)
{
struct scsi_device_handler *devinfo = NULL;
const char *drv;
int err;
err = device_create_file(&sdev->sdev_gendev, &scsi_dh_state_attr);
if (err)
return err;
drv = scsi_dh_find_driver(sdev);
if (drv)
devinfo = __scsi_dh_lookup(drv);
if (devinfo)
err = scsi_dh_handler_attach(sdev, devinfo);
return err;
}
void scsi_dh_release_device(struct scsi_device *sdev)
{
if (sdev->handler)
scsi_dh_handler_detach(sdev);
}
void scsi_dh_remove_device(struct scsi_device *sdev)
{
device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr);
}
/*
* 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);
static struct scsi_device *get_sdev_from_queue(struct request_queue *q)
{
struct scsi_device *sdev;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (!sdev || !get_device(&sdev->sdev_gendev))
sdev = NULL;
spin_unlock_irqrestore(q->queue_lock, flags);
return sdev;
}
/*
* 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 = get_sdev_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 = get_sdev_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 = get_sdev_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 = get_sdev_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);