1 files changed, 132 insertions, 30 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 62307bd794a9..e5a9526d2037 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -114,6 +114,7 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 {
 	struct Scsi_Host *host = cmd->device->host;
 	struct scsi_device *device = cmd->device;
+	struct scsi_target *starget = scsi_target(device);
 	struct request_queue *q = device->request_queue;
 	unsigned long flags;
 
@@ -133,10 +134,17 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 	 * if a command is requeued with no other commands outstanding
 	 * either for the device or for the host.
 	 */
-	if (reason == SCSI_MLQUEUE_HOST_BUSY)
+	switch (reason) {
+	case SCSI_MLQUEUE_HOST_BUSY:
 		host->host_blocked = host->max_host_blocked;
-	else if (reason == SCSI_MLQUEUE_DEVICE_BUSY)
+		break;
+	case SCSI_MLQUEUE_DEVICE_BUSY:
 		device->device_blocked = device->max_device_blocked;
+		break;
+	case SCSI_MLQUEUE_TARGET_BUSY:
+		starget->target_blocked = starget->max_target_blocked;
+		break;
+	}
 
 	/*
 	 * Decrement the counters, since these commands are no longer
@@ -460,10 +468,12 @@ static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
 void scsi_device_unbusy(struct scsi_device *sdev)
 {
 	struct Scsi_Host *shost = sdev->host;
+	struct scsi_target *starget = scsi_target(sdev);
 	unsigned long flags;
 
 	spin_lock_irqsave(shost->host_lock, flags);
 	shost->host_busy--;
+	starget->target_busy--;
 	if (unlikely(scsi_host_in_recovery(shost) &&
 		     (shost->host_failed || shost->host_eh_scheduled)))
 		scsi_eh_wakeup(shost);
@@ -519,6 +529,13 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev)
 	spin_unlock_irqrestore(shost->host_lock, flags);
 }
 
+static inline int scsi_target_is_busy(struct scsi_target *starget)
+{
+	return ((starget->can_queue > 0 &&
+		 starget->target_busy >= starget->can_queue) ||
+		 starget->target_blocked);
+}
+
 /*
  * Function:	scsi_run_queue()
  *
@@ -533,7 +550,7 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev)
  */
 static void scsi_run_queue(struct request_queue *q)
 {
-	struct scsi_device *sdev = q->queuedata;
+	struct scsi_device *starved_head = NULL, *sdev = q->queuedata;
 	struct Scsi_Host *shost = sdev->host;
 	unsigned long flags;
 
@@ -560,6 +577,21 @@ static void scsi_run_queue(struct request_queue *q)
 		 */
 		sdev = list_entry(shost->starved_list.next,
 					  struct scsi_device, starved_entry);
+		/*
+		 * The *queue_ready functions can add a device back onto the
+		 * starved list's tail, so we must check for a infinite loop.
+		 */
+		if (sdev == starved_head)
+			break;
+		if (!starved_head)
+			starved_head = sdev;
+
+		if (scsi_target_is_busy(scsi_target(sdev))) {
+			list_move_tail(&sdev->starved_entry,
+				       &shost->starved_list);
+			continue;
+		}
+
 		list_del_init(&sdev->starved_entry);
 		spin_unlock(shost->host_lock);
 
@@ -575,13 +607,6 @@ static void scsi_run_queue(struct request_queue *q)
 		spin_unlock(sdev->request_queue->queue_lock);
 
 		spin_lock(shost->host_lock);
-		if (unlikely(!list_empty(&sdev->starved_entry)))
-			/*
-			 * sdev lost a race, and was put back on the
-			 * starved list. This is unlikely but without this
-			 * in theory we could loop forever.
-			 */
-			break;
 	}
 	spin_unlock_irqrestore(shost->host_lock, flags);
 
@@ -681,7 +706,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
 			leftover = req->data_len;
 
 		/* kill remainder if no retrys */
-		if (error && blk_noretry_request(req))
+		if (error && scsi_noretry_cmd(cmd))
 			blk_end_request(req, error, leftover);
 		else {
 			if (requeue) {
@@ -1181,7 +1206,6 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 	
 	cmd->transfersize = req->data_len;
 	cmd->allowed = req->retries;
-	cmd->timeout_per_command = req->timeout;
 	return BLKPREP_OK;
 }
 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
@@ -1251,6 +1275,7 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 			break;
 		case SDEV_QUIESCE:
 		case SDEV_BLOCK:
+		case SDEV_CREATED_BLOCK:
 			/*
 			 * If the devices is blocked we defer normal commands.
 			 */
@@ -1344,6 +1369,52 @@ static inline int scsi_dev_queue_ready(struct request_queue *q,
 	return 1;
 }
 
+
+/*
+ * scsi_target_queue_ready: checks if there we can send commands to target
+ * @sdev: scsi device on starget to check.
+ *
+ * Called with the host lock held.
+ */
+static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
+					   struct scsi_device *sdev)
+{
+	struct scsi_target *starget = scsi_target(sdev);
+
+	if (starget->single_lun) {
+		if (starget->starget_sdev_user &&
+		    starget->starget_sdev_user != sdev)
+			return 0;
+		starget->starget_sdev_user = sdev;
+	}
+
+	if (starget->target_busy == 0 && starget->target_blocked) {
+		/*
+		 * unblock after target_blocked iterates to zero
+		 */
+		if (--starget->target_blocked == 0) {
+			SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
+					 "unblocking target at zero depth\n"));
+		} else {
+			blk_plug_device(sdev->request_queue);
+			return 0;
+		}
+	}
+
+	if (scsi_target_is_busy(starget)) {
+		if (list_empty(&sdev->starved_entry)) {
+			list_add_tail(&sdev->starved_entry,
+				      &shost->starved_list);
+			return 0;
+		}
+	}
+
+	/* We're OK to process the command, so we can't be starved */
+	if (!list_empty(&sdev->starved_entry))
+		list_del_init(&sdev->starved_entry);
+	return 1;
+}
+
 /*
  * scsi_host_queue_ready: if we can send requests to shost, return 1 else
  * return 0. We must end up running the queue again whenever 0 is
@@ -1390,6 +1461,7 @@ static void scsi_kill_request(struct request *req, struct request_queue *q)
 {
 	struct scsi_cmnd *cmd = req->special;
 	struct scsi_device *sdev = cmd->device;
+	struct scsi_target *starget = scsi_target(sdev);
 	struct Scsi_Host *shost = sdev->host;
 
 	blkdev_dequeue_request(req);
@@ -1413,20 +1485,30 @@ static void scsi_kill_request(struct request *req, struct request_queue *q)
 	spin_unlock(sdev->request_queue->queue_lock);
 	spin_lock(shost->host_lock);
 	shost->host_busy++;
+	starget->target_busy++;
 	spin_unlock(shost->host_lock);
 	spin_lock(sdev->request_queue->queue_lock);
 
-	__scsi_done(cmd);
+	blk_complete_request(req);
 }
 
 static void scsi_softirq_done(struct request *rq)
 {
-	struct scsi_cmnd *cmd = rq->completion_data;
-	unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
+	struct scsi_cmnd *cmd = rq->special;
+	unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
 	int disposition;
 
 	INIT_LIST_HEAD(&cmd->eh_entry);
 
+	/*
+	 * Set the serial numbers back to zero
+	 */
+	cmd->serial_number = 0;
+
+	atomic_inc(&cmd->device->iodone_cnt);
+	if (cmd->result)
+		atomic_inc(&cmd->device->ioerr_cnt);
+
 	disposition = scsi_decide_disposition(cmd);
 	if (disposition != SUCCESS &&
 	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
@@ -1541,14 +1623,13 @@ static void scsi_request_fn(struct request_queue *q)
 			goto not_ready;
 		}
 
+		if (!scsi_target_queue_ready(shost, sdev))
+			goto not_ready;
+
 		if (!scsi_host_queue_ready(q, shost, sdev))
 			goto not_ready;
-		if (scsi_target(sdev)->single_lun) {
-			if (scsi_target(sdev)->starget_sdev_user &&
-			    scsi_target(sdev)->starget_sdev_user != sdev)
-				goto not_ready;
-			scsi_target(sdev)->starget_sdev_user = sdev;
-		}
+
+		scsi_target(sdev)->target_busy++;
 		shost->host_busy++;
 
 		/*
@@ -1675,6 +1756,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
 
 	blk_queue_prep_rq(q, scsi_prep_fn);
 	blk_queue_softirq_done(q, scsi_softirq_done);
+	blk_queue_rq_timed_out(q, scsi_times_out);
 	return q;
 }
 
@@ -2064,10 +2146,13 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 
 	switch (state) {
 	case SDEV_CREATED:
-		/* There are no legal states that come back to
-		 * created.  This is the manually initialised start
-		 * state */
-		goto illegal;
+		switch (oldstate) {
+		case SDEV_CREATED_BLOCK:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
 			
 	case SDEV_RUNNING:
 		switch (oldstate) {
@@ -2105,8 +2190,17 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 
 	case SDEV_BLOCK:
 		switch (oldstate) {
-		case SDEV_CREATED:
 		case SDEV_RUNNING:
+		case SDEV_CREATED_BLOCK:
+			break;
+		default:
+			goto illegal;
+		}
+		break;
+
+	case SDEV_CREATED_BLOCK:
+		switch (oldstate) {
+		case SDEV_CREATED:
 			break;
 		default:
 			goto illegal;
@@ -2394,8 +2488,12 @@ scsi_internal_device_block(struct scsi_device *sdev)
 	int err = 0;
 
 	err = scsi_device_set_state(sdev, SDEV_BLOCK);
-	if (err)
-		return err;
+	if (err) {
+		err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
+
+		if (err)
+			return err;
+	}
 
 	/* 
 	 * The device has transitioned to SDEV_BLOCK.  Stop the
@@ -2438,8 +2536,12 @@ scsi_internal_device_unblock(struct scsi_device *sdev)
 	 * and goose the device queue if successful.  
 	 */
 	err = scsi_device_set_state(sdev, SDEV_RUNNING);
-	if (err)
-		return err;
+	if (err) {
+		err = scsi_device_set_state(sdev, SDEV_CREATED);
+
+		if (err)
+			return err;
+	}
 
 	spin_lock_irqsave(q->queue_lock, flags);
 	blk_start_queue(q);