block: print offending values when cloned rq limits are exceeded

While troubleshooting issues where cloned request limits have been
exceeded, it is often beneficial to know the actual values that
have been breached.  Print these values, assisting in ease of
identification of root cause of the breach.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -1138,7 +1138,9 @@ static int blk_cloned_rq_check_limits(struct request_queue *q,
 				      struct request *rq)
 {
 	if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) {
-		printk(KERN_ERR "%s: over max size limit.\n", __func__);
+		printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
+			__func__, blk_rq_sectors(rq),
+			blk_queue_get_max_sectors(q, req_op(rq)));
 		return -EIO;
 	}
 
@@ -1150,7 +1152,8 @@ static int blk_cloned_rq_check_limits(struct request_queue *q,
 	 */
 	blk_recalc_rq_segments(rq);
 	if (rq->nr_phys_segments > queue_max_segments(q)) {
-		printk(KERN_ERR "%s: over max segments limit.\n", __func__);
+		printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
+			__func__, rq->nr_phys_segments, queue_max_segments(q));
 		return -EIO;
 	}