scsi: don't allow setting of queue_depth bigger than can_queue

We won't ever queue more commands than the host allows.  Instead of
letting drivers either reject or ignore this case handle it in
common code.  Note that various driver use internal constant or
variables that are assigned to both shost->can_queue and checked
in ->change_queue_depth - I did remove those checks as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -2410,14 +2410,8 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 static int
 srp_change_queue_depth(struct scsi_device *sdev, int qdepth, int reason)
 {
-	struct Scsi_Host *shost = sdev->host;
-	int max_depth;
-
-	max_depth = shost->can_queue;
 	if (!sdev->tagged_supported)
-		max_depth = 1;
+		qdepth = 1;
-	if (qdepth > max_depth)
-		qdepth = max_depth;
 	scsi_adjust_queue_depth(sdev, qdepth);
 	return sdev->queue_depth;
 }

drivers/scsi/3w-9xxx.c

@@ -196,8 +196,6 @@ static int twa_change_queue_depth(struct scsi_device *sdev, int queue_depth,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -EOPNOTSUPP;
 
-	if (queue_depth > TW_Q_LENGTH-2)
-		queue_depth = TW_Q_LENGTH-2;
 	scsi_adjust_queue_depth(sdev, queue_depth);
 	return queue_depth;
 } /* End twa_change_queue_depth() */

drivers/scsi/3w-sas.c

@@ -198,8 +198,6 @@ static int twl_change_queue_depth(struct scsi_device *sdev, int queue_depth,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -EOPNOTSUPP;
 
-	if (queue_depth > TW_Q_LENGTH-2)
-		queue_depth = TW_Q_LENGTH-2;
 	scsi_adjust_queue_depth(sdev, queue_depth);
 	return queue_depth;
 } /* End twl_change_queue_depth() */

drivers/scsi/3w-xxxx.c

@@ -530,8 +530,6 @@ static int tw_change_queue_depth(struct scsi_device *sdev, int queue_depth,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -EOPNOTSUPP;
 
-	if (queue_depth > TW_Q_LENGTH-2)
-		queue_depth = TW_Q_LENGTH-2;
 	scsi_adjust_queue_depth(sdev, queue_depth);
 	return queue_depth;
 } /* End tw_change_queue_depth() */

drivers/scsi/hpsa.c

@@ -4082,11 +4082,6 @@ static int hpsa_change_queue_depth(struct scsi_device *sdev,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -ENOTSUPP;
 
-	if (qdepth < 1)
-		qdepth = 1;
-	else
-		if (qdepth > h->nr_cmds)
-			qdepth = h->nr_cmds;
 	scsi_adjust_queue_depth(sdev, qdepth);
 	return sdev->queue_depth;
 }

drivers/scsi/megaraid/megaraid_mbox.c

@@ -347,8 +347,6 @@ static int megaraid_change_queue_depth(struct scsi_device *sdev, int qdepth,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -EOPNOTSUPP;
 
-	if (qdepth > MBOX_MAX_SCSI_CMDS)
-		qdepth = MBOX_MAX_SCSI_CMDS;
 	scsi_adjust_queue_depth(sdev, qdepth);
 	return sdev->queue_depth;
 }

drivers/scsi/megaraid/megaraid_sas_base.c

@@ -2597,8 +2597,6 @@ static int megasas_change_queue_depth(struct scsi_device *sdev,
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		return -EOPNOTSUPP;
 
-	if (queue_depth > sdev->host->can_queue)
-		queue_depth = sdev->host->can_queue;
 	scsi_adjust_queue_depth(sdev, queue_depth);
 
 	return queue_depth;

drivers/scsi/scsi_sysfs.c

@@ -877,7 +877,7 @@ sdev_store_queue_depth(struct device *dev, struct device_attribute *attr,
 
 	depth = simple_strtoul(buf, NULL, 0);
 
-	if (depth < 1)
+	if (depth < 1 || depth > sht->can_queue)
 		return -EINVAL;
 
 	retval = sht->change_queue_depth(sdev, depth,

drivers/scsi/vmw_pvscsi.c

@@ -508,20 +508,14 @@ static int pvscsi_change_queue_depth(struct scsi_device *sdev,
 				     int qdepth,
 				     int reason)
 {
-	int max_depth;
-	struct Scsi_Host *shost = sdev->host;
-
 	if (reason != SCSI_QDEPTH_DEFAULT)
 		/*
 		 * We support only changing default.
 		 */
 		return -EOPNOTSUPP;
 
-	max_depth = shost->can_queue;
 	if (!sdev->tagged_supported)
-		max_depth = 1;
+		qdepth = 1;
-	if (qdepth > max_depth)
-		qdepth = max_depth;
 	scsi_adjust_queue_depth(sdev, qdepth);
 
 	if (sdev->inquiry_len > 7)