  For a finite-dimensional gentle algebra, it is already known that the
functorially finite torsion classes of its category of finite-dimensional
modules can be classified using a combinatorial interpretation, called maximal
non-crossing sets of strings, of the corresponding support $\tau$-tilting
module (or equivalently, two-term silting complexes). In the topological
interpretation of gentle algebras via marked surfaces, such a set can be
interpreted as a dissection (or partial triangulation), or equivalently, a
lamination that does not contain a closed curve. We will refine this
combinatorics, which gives us a classification of torsion classes in the
category of finite length modules over a (possibly infinite-dimensional) gentle
algebra. As a consequence, our result also unifies the functorially finite
torsion class classification of finite-dimensional gentle algebras with certain
classes of special biserial algebras - such as Brauer graph algebras.
