mmap() interface for device special files?

Jeff Newbern (
Sun, 23 Jul 1995 17:36:57 EDT

Is there any documentation around on the correct implementation of
*_mmap() in a character device driver? I looked through the existing
drivers, but could not find any that fill in the *_mmap field in the
*_fops structure. Is this because the mmap() functionality is
incomplete, or just because no one feels like supporting an mmap()
interface, or just that the drivers were written before mmap()?

Thanks for any tips or pointers,
Jeff Newbern

PS. I looked in the Linux Kernel Hacker's Guide (great job, mjohnson!)
but that section has yet to be completed.

Jeff Newbern Linux Publicity Project