1 files changed, 415 insertions, 31 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index ab6c21cd968..a518f2eff19 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -24,8 +24,16 @@
 #include <scsi/scsi_dh.h>
 #include "../scsi_priv.h"
 
+struct scsi_dh_devinfo_list {
+	struct list_head node;
+	char vendor[9];
+	char model[17];
+	struct scsi_device_handler *handler;
+};
+
 static DEFINE_SPINLOCK(list_lock);
 static LIST_HEAD(scsi_dh_list);
+static LIST_HEAD(scsi_dh_dev_list);
 
 static struct scsi_device_handler *get_device_handler(const char *name)
 {
@@ -33,7 +41,7 @@ static struct scsi_device_handler *get_device_handler(const char *name)
 
 	spin_lock(&list_lock);
 	list_for_each_entry(tmp, &scsi_dh_list, list) {
-		if (!strcmp(tmp->name, name)) {
+		if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 			found = tmp;
 			break;
 		}
@@ -42,11 +50,307 @@ static struct scsi_device_handler *get_device_handler(const char *name)
 	return found;
 }
 
+
+static struct scsi_device_handler *
+scsi_dh_cache_lookup(struct scsi_device *sdev)
+{
+	struct scsi_dh_devinfo_list *tmp;
+	struct scsi_device_handler *found_dh = NULL;
+
+	spin_lock(&list_lock);
+	list_for_each_entry(tmp, &scsi_dh_dev_list, node) {
+		if (!strncmp(sdev->vendor, tmp->vendor, strlen(tmp->vendor)) &&
+		    !strncmp(sdev->model, tmp->model, strlen(tmp->model))) {
+			found_dh = tmp->handler;
+			break;
+		}
+	}
+	spin_unlock(&list_lock);
+
+	return found_dh;
+}
+
+static int scsi_dh_handler_lookup(struct scsi_device_handler *scsi_dh,
+				  struct scsi_device *sdev)
+{
+	int i, found = 0;
+
+	for(i = 0; scsi_dh->devlist[i].vendor; i++) {
+		if (!strncmp(sdev->vendor, scsi_dh->devlist[i].vendor,
+			     strlen(scsi_dh->devlist[i].vendor)) &&
+		    !strncmp(sdev->model, scsi_dh->devlist[i].model,
+			     strlen(scsi_dh->devlist[i].model))) {
+			found = 1;
+			break;
+		}
+	}
+	return found;
+}
+
+/*
+ * device_handler_match - Attach a device handler to a device
+ * @scsi_dh - The device handler to match against or NULL
+ * @sdev - SCSI device to be tested against @scsi_dh
+ *
+ * Tests @sdev against the device handler @scsi_dh or against
+ * all registered device_handler if @scsi_dh == NULL.
+ * Returns the found device handler or NULL if not found.
+ */
+static struct scsi_device_handler *
+device_handler_match(struct scsi_device_handler *scsi_dh,
+		     struct scsi_device *sdev)
+{
+	struct scsi_device_handler *found_dh = NULL;
+	struct scsi_dh_devinfo_list *tmp;
+
+	found_dh = scsi_dh_cache_lookup(sdev);
+	if (found_dh)
+		return found_dh;
+
+	if (scsi_dh) {
+		if (scsi_dh_handler_lookup(scsi_dh, sdev))
+			found_dh = scsi_dh;
+	} else {
+		struct scsi_device_handler *tmp_dh;
+
+		spin_lock(&list_lock);
+		list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
+			if (scsi_dh_handler_lookup(tmp_dh, sdev))
+				found_dh = tmp_dh;
+		}
+		spin_unlock(&list_lock);
+	}
+
+	if (found_dh) { /* If device is found, add it to the cache */
+		tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+		if (tmp) {
+			strncpy(tmp->vendor, sdev->vendor, 8);
+			strncpy(tmp->model, sdev->model, 16);
+			tmp->vendor[8] = '\0';
+			tmp->model[16] = '\0';
+			tmp->handler = found_dh;
+			spin_lock(&list_lock);
+			list_add(&tmp->node, &scsi_dh_dev_list);
+			spin_unlock(&list_lock);
+		} else {
+			found_dh = NULL;
+		}
+	}
+
+	return found_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 err = 0;
+
+	if (sdev->scsi_dh_data) {
+		if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
+			err = -EBUSY;
+	} else if (scsi_dh->attach)
+		err = scsi_dh->attach(sdev);
+
+	return err;
+}
+
+/*
+ * scsi_dh_handler_detach - Detach a device handler from a device
+ * @sdev - SCSI device the device handler should be detached from
+ * @scsi_dh - Device handler to be detached
+ *
+ * Detach from a device handler. If a device handler is specified,
+ * only detach if the currently attached handler matches @scsi_dh.
+ */
+static void scsi_dh_handler_detach(struct scsi_device *sdev,
+				   struct scsi_device_handler *scsi_dh)
+{
+	if (!sdev->scsi_dh_data)
+		return;
+
+	if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh)
+		return;
+
+	if (!scsi_dh)
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+
+	if (scsi_dh && scsi_dh->detach)
+		scsi_dh->detach(sdev);
+}
+
+/*
+ * 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->scsi_dh_data) {
+		/*
+		 * Attach to a device handler
+		 */
+		if (!(scsi_dh = get_device_handler(buf)))
+			return err;
+		err = scsi_dh_handler_attach(sdev, scsi_dh);
+	} else {
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+		if (!strncmp(buf, "detach", 6)) {
+			/*
+			 * Detach from a device handler
+			 */
+			scsi_dh_handler_detach(sdev, scsi_dh);
+			err = 0;
+		} else if (!strncmp(buf, "activate", 8)) {
+			/*
+			 * Activate a device handler
+			 */
+			if (scsi_dh->activate)
+				err = scsi_dh->activate(sdev);
+			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->scsi_dh_data)
+		return snprintf(buf, 20, "detached\n");
+
+	return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name);
+}
+
+static struct device_attribute scsi_dh_state_attr =
+	__ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
+	       store_dh_state);
+
+/*
+ * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh
+ */
+static int scsi_dh_sysfs_attr_add(struct device *dev, void *data)
+{
+	struct scsi_device *sdev;
+	int err;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	err = device_create_file(&sdev->sdev_gendev,
+				 &scsi_dh_state_attr);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh
+ */
+static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data)
+{
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	device_remove_file(&sdev->sdev_gendev,
+			   &scsi_dh_state_attr);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_notifier - notifier chain callback
+ */
+static int scsi_dh_notifier(struct notifier_block *nb,
+			    unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev;
+	int err = 0;
+	struct scsi_device_handler *devinfo = NULL;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		devinfo = device_handler_match(NULL, sdev);
+		if (!devinfo)
+			goto out;
+
+		err = scsi_dh_handler_attach(sdev, devinfo);
+		if (!err)
+			err = device_create_file(dev, &scsi_dh_state_attr);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		device_remove_file(dev, &scsi_dh_state_attr);
+		scsi_dh_handler_detach(sdev, NULL);
+	}
+out:
+	return err;
+}
+
+/*
+ * scsi_dh_notifier_add - Callback for scsi_register_device_handler
+ */
 static int scsi_dh_notifier_add(struct device *dev, void *data)
 {
 	struct scsi_device_handler *scsi_dh = data;
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	if (!get_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	if (device_handler_match(scsi_dh, sdev))
+		scsi_dh_handler_attach(sdev, scsi_dh);
+
+	put_device(dev);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler
+ */
+static int scsi_dh_notifier_remove(struct device *dev, void *data)
+{
+	struct scsi_device_handler *scsi_dh = data;
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	if (!get_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	scsi_dh_handler_detach(sdev, scsi_dh);
+
+	put_device(dev);
 
-	scsi_dh->nb.notifier_call(&scsi_dh->nb, BUS_NOTIFY_ADD_DEVICE, dev);
 	return 0;
 }
 
@@ -59,33 +363,19 @@ static int scsi_dh_notifier_add(struct device *dev, void *data)
  */
 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 {
-	int ret = -EBUSY;
-	struct scsi_device_handler *tmp;
+	if (get_device_handler(scsi_dh->name))
+		return -EBUSY;
 
-	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);
+	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
+	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 
-done:
-	return ret;
+	return SCSI_DH_OK;
 }
 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.
@@ -95,23 +385,26 @@ static int scsi_dh_notifier_remove(struct device *dev, void *data)
  */
 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;
+	struct scsi_dh_devinfo_list *tmp, *pos;
 
-	ret = bus_unregister_notifier(&scsi_bus_type, &scsi_dh->nb);
+	if (!get_device_handler(scsi_dh->name))
+		return -ENODEV;
 
 	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
-					scsi_dh_notifier_remove);
+			 scsi_dh_notifier_remove);
+
 	spin_lock(&list_lock);
 	list_del(&scsi_dh->list);
+	list_for_each_entry_safe(pos, tmp, &scsi_dh_dev_list, node) {
+		if (pos->handler == scsi_dh) {
+			list_del(&pos->node);
+			kfree(pos);
+		}
+	}
 	spin_unlock(&list_lock);
+	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 
-done:
-	return ret;
+	return SCSI_DH_OK;
 }
 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 
@@ -157,6 +450,97 @@ int scsi_dh_handler_exist(const char *name)
 }
 EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
 
+/*
+ * scsi_dh_handler_attach - Attach device handler
+ * @sdev - sdev the handler should be attached to
+ * @name - name of the handler to attach
+ */
+int scsi_dh_attach(struct request_queue *q, const char *name)
+{
+	unsigned long flags;
+	struct scsi_device *sdev;
+	struct scsi_device_handler *scsi_dh;
+	int err = 0;
+
+	scsi_dh = get_device_handler(name);
+	if (!scsi_dh)
+		return -EINVAL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (!sdev || !get_device(&sdev->sdev_gendev))
+		err = -ENODEV;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (!err) {
+		err = scsi_dh_handler_attach(sdev, scsi_dh);
+
+		put_device(&sdev->sdev_gendev);
+	}
+	return err;
+}
+EXPORT_SYMBOL_GPL(scsi_dh_attach);
+
+/*
+ * scsi_dh_handler_detach - Detach device handler
+ * @sdev - sdev the handler should be detached from
+ *
+ * This function will detach the device handler only
+ * if the sdev is not part of the internal list, ie
+ * if it has been attached manually.
+ */
+void scsi_dh_detach(struct request_queue *q)
+{
+	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 || !get_device(&sdev->sdev_gendev))
+		sdev = NULL;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (!sdev)
+		return;
+
+	if (sdev->scsi_dh_data) {
+		/* if sdev is not on internal list, detach */
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+		if (!device_handler_match(scsi_dh, sdev))
+			scsi_dh_handler_detach(sdev, scsi_dh);
+	}
+	put_device(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL_GPL(scsi_dh_detach);
+
+static struct notifier_block scsi_dh_nb = {
+	.notifier_call = scsi_dh_notifier
+};
+
+static int __init scsi_dh_init(void)
+{
+	int r;
+
+	r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb);
+
+	if (!r)
+		bus_for_each_dev(&scsi_bus_type, NULL, NULL,
+				 scsi_dh_sysfs_attr_add);
+
+	return r;
+}
+
+static void __exit scsi_dh_exit(void)
+{
+	bus_for_each_dev(&scsi_bus_type, NULL, NULL,
+			 scsi_dh_sysfs_attr_remove);
+	bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb);
+}
+
+module_init(scsi_dh_init);
+module_exit(scsi_dh_exit);
+
 MODULE_DESCRIPTION("SCSI device handler");
 MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
 MODULE_LICENSE("GPL");