hpsa: correct off-by-one sizing of chained SG block

Correct the size calculation of the chained SG block

Signed-off-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Webb Scales <webbnh@hp.com>
Reviewed-by: Stephen M. Cameron <stephenmcameron@gmail.com>
Reviewed-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index f0984c6..4ca94a5 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -6321,11 +6321,11 @@
 	h->max_cmd_sg_entries = 31;
 	if (h->maxsgentries > 512) {
 		h->max_cmd_sg_entries = 32;
-		h->chainsize = h->maxsgentries - h->max_cmd_sg_entries + 1;
+		h->chainsize = h->maxsgentries - h->max_cmd_sg_entries;
 		h->maxsgentries--; /* save one for chain pointer */
 	} else {
-		h->maxsgentries = 31; /* default to traditional values */
 		h->chainsize = 0;
+		h->maxsgentries = 31; /* default to traditional values */
 	}
 
 	/* Find out what task management functions are supported and cache */