scsi: core: Avoid printing an error if target_alloc() returns -ENXIO

Avoid printing a 'target allocation failed' error if the driver
target_alloc() callback function returns -ENXIO. This return value
indicates that the corresponding H:C:T:L entry is empty.

Removing this error reduces the scan time if the user issues SCAN_WILD_CARD
scan operation through sysfs parameter on a host with a lot of empty
H:C:T:L entries.

Avoiding the printk on -ENXIO matches the behavior of the other callback
functions during scanning.

Link: https://lore.kernel.org/r/20210726115402.1936-1-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_scan.c

@@ -475,7 +475,8 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
 		error = shost->hostt->target_alloc(starget);
 
 		if(error) {
-			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
+			if (error != -ENXIO)
+				dev_err(dev, "target allocation failed, error %d\n", error);
 			/* don't want scsi_target_reap to do the final
 			 * put because it will be under the host lock */
 			scsi_target_destroy(starget);