[linux.git] / drivers / block / loop.c

/*
 *  linux/drivers/block/loop.c
 *
 *  Written by Theodore Ts'o, 3/29/93
 *
 * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
 * permitted under the GNU General Public License.
 *
 * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
 * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
 *
 * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
 * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
 *
 * Fixed do_loop_request() re-entrancy - [email protected] Mar 20, 1997
 *
 * Added devfs support - Richard Gooch <[email protected]> 16-Jan-1998
 *
 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
 *
 * Loadable modules and other fixes by AK, 1998
 *
 * Make real block number available to downstream transfer functions, enables
 * CBC (and relatives) mode encryption requiring unique IVs per data block.
 * Reed H. Petty, [email protected]
 *
 * Maximum number of loop devices now dynamic via max_loop module parameter.
 * Russell Kroll <[email protected]> 19990701
 *
 * Maximum number of loop devices when compiled-in now selectable by passing
 * max_loop=<1-255> to the kernel on boot.
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/block/loop.c
	3	*
	4	* Written by Theodore Ts'o, 3/29/93
	5	*
	6	* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
	7	* permitted under the GNU General Public License.
	8	*
	9	* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
	10	* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
	11	*
	12	* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
	13	* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
	14	*
	15	* Fixed do_loop_request() re-entrancy - [email protected] Mar 20, 1997
	16	*
	17	* Added devfs support - Richard Gooch <[email protected]> 16-Jan-1998
	18	*
	19	* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
	20	*
	21	* Loadable modules and other fixes by AK, 1998
	22	*
	23	* Make real block number available to downstream transfer functions, enables
	24	* CBC (and relatives) mode encryption requiring unique IVs per data block.
	25	* Reed H. Petty, [email protected]
	26	*
	27	* Maximum number of loop devices now dynamic via max_loop module parameter.
	28	* Russell Kroll <[email protected]> 19990701
	29	*
	30	* Maximum number of loop devices when compiled-in now selectable by passing
	31	* max_loop=<1-255> to the kernel on boot.
	32