When you design a local SSRS report you are forced to use a Dataset as part of the design process, however, this does not mean that you have to keep the dependancy on a dataset or even retain the dataset in your project once you have completed the design.
Simply use code similar to the C# example that follows to clear the dataset the report is expecting to use and specify the new collection of data it is to use instead:
var context = new AWEntities();
var vendors = from v in context.Vendors
where v.CreditRating != 1
ReportDataSource datasource = new ReportDataSource("VendorList", vendors);
You can use the same method to substitute data from Linq to SQL or ADO.NET if they are your DAL technology of choice.