Documentation/usb/mass-storage.rst

2 Mass Storage Gadget (MSG)
8   Mass Storage Gadget (or MSG) acts as a USB Mass Storage device,
12   to read-only, and gadget can indicate that it is removable and/or
26   This document describes how to use the gadget from user space, its
28   using it, and how it differs from File Storage Gadget (or FSG)
35   The mass storage gadget accepts the following mass storage specific
62     If this option is set for a logical unit, gadget will accept an
75     true.  This has been changed to better match File Storage Gadget
83     reader).  It does *not* mean that the entire gadget can be
99     backing file could not be opened in read/write mode, the gadget
125     This parameter specifies number of logical units the gadget will
140     Specifies whether the gadget is allowed to halt bulk endpoints.
144   In addition to the above, the gadget also accepts the following
158   For each logical unit, the gadget creates a directory in the sysfs
199   The Mass Storage Gadget uses the Mass Storage Function to handle
207   consult the gadget's documentation or its source code.
213 Relation to file storage gadget
216   The Mass Storage Function and thus the Mass Storage Gadget has been
217   based on the File Storage Gadget.  The difference between the two is
218   that MSG is a composite gadget (ie. uses the composite framework)
219   while file storage gadget was a traditional gadget.  From userspace
223   (ii) MSF can be used in any other composite gadget.
225   Because of that, File Storage Gadget has been removed in Linux 3.8.
226   All users need to transition to the Mass Storage Gadget.  The two