Extension Methods FTW!

var query = context.Songs
                            .WhereIf(request.Artist.IsNotNull(), b => b.Artist == request.Artist)
                            .WhereIf(request.Genre.IsNotNull(), b => b.Genre == request.Genre)
                            .WhereIf(request.Title.IsNotNull(), b => b.Title == request.Title)
                            .WhereIf(request.Label.IsNotNull(), b => b.Label == request.Label);