1 files changed, 437 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c
new file mode 100644
index 000000000000..0a2168e69bbc
--- /dev/null
+++ b/drivers/scsi/scsi_dh.c
@@ -0,0 +1,437 @@
+/*
+ * 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_remove_device(struct scsi_device *sdev)
+{
+	if (sdev->handler)
+		scsi_dh_handler_detach(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);