diff options
Diffstat (limited to 'drivers/scsi/scsi_dh.c')
| -rw-r--r-- | drivers/scsi/scsi_dh.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c new file mode 100644 index 000000000..e7649ed3f --- /dev/null +++ b/drivers/scsi/scsi_dh.c @@ -0,0 +1,441 @@ +/* + * 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); |