RDMA/rw: Add info regarding SG count failure

Print the supported and wanted values for SG count during signature
operation.
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/rw.c

@@ -357,7 +357,8 @@ int rdma_rw_ctx_signature_init(struct rdma_rw_ctx *ctx, struct ib_qp *qp,
 	int count = 0, ret;
 
 	if (sg_cnt > pages_per_mr || prot_sg_cnt > pages_per_mr) {
-		pr_err("SG count too large\n");
+		pr_err("SG count too large: sg_cnt=%d, prot_sg_cnt=%d, pages_per_mr=%d\n",
+		       sg_cnt, prot_sg_cnt, pages_per_mr);
 		return -EINVAL;
 	}