1 files changed, 115 insertions, 29 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5feb886c3392..f2a72d33132c 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/blkdev.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/init.h>
@@ -52,21 +53,100 @@ static struct class shost_class = {
 };
 
 /**
- * scsi_host_cancel - cancel outstanding IO to this host
- * @shost:	pointer to struct Scsi_Host
- * recovery:	recovery requested to run.
+ *	scsi_host_set_state - Take the given host through the host
+ *		state model.
+ *	@shost:	scsi host to change the state of.
+ *	@state:	state to change to.
+ *
+ *	Returns zero if unsuccessful or an error if the requested
+ *	transition is illegal.
  **/
-static void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
+int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
 {
-	struct scsi_device *sdev;
+	enum scsi_host_state oldstate = shost->shost_state;
+
+	if (state == oldstate)
+		return 0;
+
+	switch (state) {
+	case SHOST_CREATED:
+		/* There are no legal states that come back to
+		 * created.  This is the manually initialised start
+		 * state */
+		goto illegal;
+
+	case SHOST_RUNNING:
+		switch (oldstate) {
+		case SHOST_CREATED:
+		case SHOST_RECOVERY:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
+
+	case SHOST_RECOVERY:
+		switch (oldstate) {
+		case SHOST_RUNNING:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
 
-	set_bit(SHOST_CANCEL, &shost->shost_state);
-	shost_for_each_device(sdev, shost) {
-		scsi_device_cancel(sdev, recovery);
+	case SHOST_CANCEL:
+		switch (oldstate) {
+		case SHOST_CREATED:
+		case SHOST_RUNNING:
+		case SHOST_CANCEL_RECOVERY:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
+
+	case SHOST_DEL:
+		switch (oldstate) {
+		case SHOST_CANCEL:
+		case SHOST_DEL_RECOVERY:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
+
+	case SHOST_CANCEL_RECOVERY:
+		switch (oldstate) {
+		case SHOST_CANCEL:
+		case SHOST_RECOVERY:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
+
+	case SHOST_DEL_RECOVERY:
+		switch (oldstate) {
+		case SHOST_CANCEL_RECOVERY:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
 	}
-	wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
-						&shost->shost_state)));
+	shost->shost_state = state;
+	return 0;
+
+ illegal:
+	SCSI_LOG_ERROR_RECOVERY(1,
+				dev_printk(KERN_ERR, &shost->shost_gendev,
+					   "Illegal host state transition"
+					   "%s->%s\n",
+					   scsi_host_state_name(oldstate),
+					   scsi_host_state_name(state)));
+	return -EINVAL;
 }
+EXPORT_SYMBOL(scsi_host_set_state);
 
 /**
  * scsi_remove_host - remove a scsi host
@@ -74,11 +154,24 @@ static void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
  **/
 void scsi_remove_host(struct Scsi_Host *shost)
 {
+	unsigned long flags;
+	down(&shost->scan_mutex);
+	spin_lock_irqsave(shost->host_lock, flags);
+	if (scsi_host_set_state(shost, SHOST_CANCEL))
+		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
+			spin_unlock_irqrestore(shost->host_lock, flags);
+			up(&shost->scan_mutex);
+			return;
+		}
+	spin_unlock_irqrestore(shost->host_lock, flags);
+	up(&shost->scan_mutex);
 	scsi_forget_host(shost);
-	scsi_host_cancel(shost, 0);
 	scsi_proc_host_rm(shost);
 
-	set_bit(SHOST_DEL, &shost->shost_state);
+	spin_lock_irqsave(shost->host_lock, flags);
+	if (scsi_host_set_state(shost, SHOST_DEL))
+		BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
+	spin_unlock_irqrestore(shost->host_lock, flags);
 
 	transport_unregister_device(&shost->shost_gendev);
 	class_device_unregister(&shost->shost_classdev);
@@ -115,7 +208,7 @@ int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 	if (error)
 		goto out;
 
-	set_bit(SHOST_ADD, &shost->shost_state);
+	scsi_host_set_state(shost, SHOST_RUNNING);
 	get_device(shost->shost_gendev.parent);
 
 	error = class_device_add(&shost->shost_classdev);
@@ -164,15 +257,8 @@ static void scsi_host_dev_release(struct device *dev)
 	struct Scsi_Host *shost = dev_to_shost(dev);
 	struct device *parent = dev->parent;
 
-	if (shost->ehandler) {
-		DECLARE_COMPLETION(sem);
-		shost->eh_notify = &sem;
-		shost->eh_kill = 1;
-		up(shost->eh_wait);
-		wait_for_completion(&sem);
-		shost->eh_notify = NULL;
-	}
-
+	if (shost->ehandler)
+		kthread_stop(shost->ehandler);
 	if (shost->work_q)
 		destroy_workqueue(shost->work_q);
 
@@ -202,7 +288,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 {
 	struct Scsi_Host *shost;
 	int gfp_mask = GFP_KERNEL, rval;
-	DECLARE_COMPLETION(complete);
 
 	if (sht->unchecked_isa_dma && privsize)
 		gfp_mask |= __GFP_DMA;
@@ -226,6 +311,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 
 	spin_lock_init(&shost->default_lock);
 	scsi_assign_lock(shost, &shost->default_lock);
+	shost->shost_state = SHOST_CREATED;
 	INIT_LIST_HEAD(&shost->__devices);
 	INIT_LIST_HEAD(&shost->__targets);
 	INIT_LIST_HEAD(&shost->eh_cmd_q);
@@ -307,12 +393,12 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 		  shost->host_no);
 
-	shost->eh_notify = &complete;
-	rval = kernel_thread(scsi_error_handler, shost, 0);
-	if (rval < 0)
+	shost->ehandler = kthread_run(scsi_error_handler, shost,
+			"scsi_eh_%d", shost->host_no);
+	if (IS_ERR(shost->ehandler)) {
+		rval = PTR_ERR(shost->ehandler);
 		goto fail_destroy_freelist;
-	wait_for_completion(&complete);
-	shost->eh_notify = NULL;
+	}
 
 	scsi_proc_hostdir_add(shost->hostt);
 	return shost;
@@ -382,7 +468,7 @@ EXPORT_SYMBOL(scsi_host_lookup);
  **/
 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 {
-	if (test_bit(SHOST_DEL, &shost->shost_state) ||
+	if ((shost->shost_state == SHOST_DEL) ||
 		!get_device(&shost->shost_gendev))
 		return NULL;
 	return shost;