The size of the default reserved buffer can be specified when the sg driver is loaded. If it is built into the kernel then use:

    sg_def_reserved_size=<n>

on the boot line (only supported in 2.4 kernels).

If sg is a module, it can be loaded with modprobe in either manner:

    modprobe sg
    modprobe sg def_reserved_size=<n>

In the second case "<n>" is an integer (non negative). The default value is the value of the SG_DEF_RESERVED_SIZE defined in sg.h . This is currently 32768.

If sg is a module, it can be unloaded with rmmod like this:

    rmmod sg

However if there is a file descriptor still open with the sg driver (or there is an outstanding request awaiting a response) then the sg module is considered to be busy and can't be unloaded.