/*   pdcraid.c  Copyright (C) 2001 Red Hat, Inc. All rights reserved.   This program is free software; you can redistribute it and/or modify   it under the terms of the GNU General Public License as published by   the Free Software Foundation; either version 2, or (at your option)   any later version.      You should have received a copy of the GNU General Public License   (for example /usr/src/linux/COPYING); if not, write to the Free   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.        Authors: 	Arjan van de Ven <arjanv@redhat.com>   		   Based on work done by S鴕en Schmidt for FreeBSD  */#include <linux/module.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/sched.h>#include <linux/smp_lock.h>#include <linux/blkdev.h>#include <linux/blkpg.h>#include <linux/genhd.h>#include <linux/ioctl.h>#include <linux/ide.h>#include <asm/uaccess.h>#include "ataraid.h"static int pdcraid_open(struct inode * inode, struct file * filp);static int pdcraid_release(struct inode * inode, struct file * filp);static int pdcraid_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);static int pdcraid0_make_request (request_queue_t *q, int rw, struct buffer_head * bh);static int pdcraid1_make_request (request_queue_t *q, int rw, struct buffer_head * bh);struct disk_dev {	int major;	int minor;	int device;};static struct disk_dev devlist[]= {	{IDE0_MAJOR,  0,  -1 },	{IDE0_MAJOR, 64,  -1 },	{IDE1_MAJOR,  0,  -1 },	{IDE1_MAJOR, 64,  -1 },	{IDE2_MAJOR,  0,  -1 },	{IDE2_MAJOR, 64,  -1 },	{IDE3_MAJOR,  0,  -1 },	{IDE3_MAJOR, 64,  -1 },	{IDE4_MAJOR,  0,  -1 },	{IDE4_MAJOR, 64,  -1 },	{IDE5_MAJOR,  0,  -1 },	{IDE5_MAJOR, 64,  -1 },	{IDE6_MAJOR,  0,  -1 },	{IDE6_MAJOR, 64,  -1 },};struct pdcdisk {	kdev_t	device;	unsigned long sectors;	struct block_device *bdev;	unsigned long last_pos;};struct pdcraid {	unsigned int stride;	unsigned int disks;	unsigned long sectors;	struct geom geom;		struct pdcdisk disk[8];		unsigned long cutoff[8];	unsigned int cutoff_disks[8];};static struct raid_device_operations pdcraid0_ops = {        open:                   pdcraid_open,	release:                pdcraid_release,	ioctl:			pdcraid_ioctl,	make_request:		pdcraid0_make_request};static struct raid_device_operations pdcraid1_ops = {        open:                   pdcraid_open,	release:                pdcraid_release,	ioctl:			pdcraid_ioctl,	make_request:		pdcraid1_make_request};static struct pdcraid raid[16];static int pdcraid_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg){	unsigned int minor;   	unsigned long sectors;	if (!inode || !inode->i_rdev) 		return -EINVAL;	minor = MINOR(inode->i_rdev)>>SHIFT;		switch (cmd) {         	case BLKGETSIZE:   /* Return device size */ 			if (!arg)  return -EINVAL;			sectors = ataraid_gendisk.part[MINOR(inode->i_rdev)].nr_sects;			if (MINOR(inode->i_rdev)&15)				return put_user(sectors, (unsigned long *) arg);			return put_user(raid[minor].sectors , (unsigned long *) arg);			break;					case HDIO_GETGEO:		{			struct hd_geometry *loc = (struct hd_geometry *) arg;			unsigned short bios_cyl = raid[minor].geom.cylinders; /* truncate */						if (!loc) return -EINVAL;			if (put_user(raid[minor].geom.heads, (byte *) &loc->heads)) return -EFAULT;			if (put_user(raid[minor].geom.sectors, (byte *) &loc->sectors)) return -EFAULT;			if (put_user(bios_cyl, (unsigned short *) &loc->cylinders)) return -EFAULT;			if (put_user((unsigned)ataraid_gendisk.part[MINOR(inode->i_rdev)].start_sect,				(unsigned long *) &loc->start)) return -EFAULT;			return 0;		}		case HDIO_GETGEO_BIG:		{			struct hd_big_geometry *loc = (struct hd_big_geometry *) arg;			if (!loc) return -EINVAL;			if (put_user(raid[minor].geom.heads, (byte *) &loc->heads)) return -EFAULT;			if (put_user(raid[minor].geom.sectors, (byte *) &loc->sectors)) return -EFAULT;			if (put_user(raid[minor].geom.cylinders, (unsigned int *) &loc->cylinders)) return -EFAULT;			if (put_user((unsigned)ataraid_gendisk.part[MINOR(inode->i_rdev)].start_sect,				(unsigned long *) &loc->start)) return -EFAULT;			return 0;		}		default:			return blk_ioctl(inode->i_rdev, cmd, arg);	};	return 0;}static unsigned long partition_map_normal(unsigned long block, unsigned long partition_off, unsigned long partition_size, int stride){	return block + partition_off;}static int pdcraid0_make_request (request_queue_t *q, int rw, struct buffer_head * bh){	unsigned long rsect;	unsigned long rsect_left,rsect_accum = 0;	unsigned long block;	unsigned int disk=0,real_disk=0;	int i;	int device;	struct pdcraid *thisraid;	rsect = bh->b_rsector;		/* Ok. We need to modify this sector number to a new disk + new sector number. 	 * If there are disks of different sizes, this gets tricky. 	 * Example with 3 disks (1Gb, 4Gb and 5 GB):	 * The first 3 Gb of the "RAID" are evenly spread over the 3 disks.	 * Then things get interesting. The next 2Gb (RAID view) are spread across disk 2 and 3	 * and the last 1Gb is disk 3 only.	 *	 * the way this is solved is like this: We have a list of "cutoff" points where everytime	 * a disk falls out of the "higher" count, we mark the max sector. So once we pass a cutoff	 * point, we have to divide by one less.	 */		device = (bh->b_rdev >> SHIFT)&MAJOR_MASK;	thisraid = &raid[device];	if (thisraid->stride==0)		thisraid->stride=1;	/* Partitions need adding of the start sector of the partition to the requested sector */		rsect = partition_map_normal(rsect, ataraid_gendisk.part[MINOR(bh->b_rdev)].start_sect, ataraid_gendisk.part[MINOR(bh->b_rdev)].nr_sects, thisraid->stride);	/* Woops we need to split the request to avoid crossing a stride barrier */	if ((rsect/thisraid->stride) != ((rsect+(bh->b_size/512)-1)/thisraid->stride)) {		return -1;  	}		rsect_left = rsect;		for (i=0;i<8;i++) {		if (thisraid->cutoff_disks[i]==0)			break;		if (rsect > thisraid->cutoff[i]) {			/* we're in the wrong area so far */			rsect_left -= thisraid->cutoff[i];			rsect_accum += thisraid->cutoff[i]/thisraid->cutoff_disks[i];		} else {			block = rsect_left / thisraid->stride;			disk = block % thisraid->cutoff_disks[i];			block = (block / thisraid->cutoff_disks[i]) * thisraid->stride;			rsect = rsect_accum + (rsect_left % thisraid->stride) + block;			break;		}	}		for (i=0;i<8;i++) {		if ((disk==0) && (thisraid->disk[i].sectors > rsect_accum)) {			real_disk = i;			break;		}		if ((disk>0) && (thisraid->disk[i].sectors >= rsect_accum)) {			disk--;		}			}	disk = real_disk;				/*	 * The new BH_Lock semantics in ll_rw_blk.c guarantee that this	 * is the only IO operation happening on this bh.	 */	bh->b_rdev = thisraid->disk[disk].device;	bh->b_rsector = rsect;	/*	 * Let the main block layer submit the IO and resolve recursion:	 */	return 1;}static int pdcraid1_write_request(request_queue_t *q, int rw, struct buffer_head * bh){	struct buffer_head *bh1;	struct ataraid_bh_private *private;	int device;	int i;	device = (bh->b_rdev >> SHIFT)&MAJOR_MASK;	private = ataraid_get_private();	if (private==NULL)		BUG();	private->parent = bh;		atomic_set(&private->count,raid[device].disks);	for (i = 0; i< raid[device].disks; i++) { 		bh1=ataraid_get_bhead();		/* If this ever fails we're doomed */		if (!bh1)			BUG();			/* dupe the bufferhead and update the parts that need to be different */		memcpy(bh1, bh, sizeof(*bh));				bh1->b_end_io = ataraid_end_request;		bh1->b_private = private;		bh1->b_rsector += ataraid_gendisk.part[MINOR(bh->b_rdev)].start_sect; /* partition offset */		bh1->b_rdev = raid[device].disk[i].device;		/* update the last known head position for the drive */		raid[device].disk[i].last_pos = bh1->b_rsector+(bh1->b_size>>9);		generic_make_request(rw,bh1);	}	return 0;}static int pdcraid1_read_request (request_queue_t *q, int rw, struct buffer_head * bh){	int device;	int dist;	int bestsofar,bestdist,i;	static int previous;	/* Reads are simple in principle. Pick a disk and go. 	   Initially I cheat by just picking the one which the last known	   head position is closest by.	   Later on, online/offline checking and performance needs adding */		device = (bh->b_rdev >> SHIFT)&MAJOR_MASK;	bh->b_rsector += ataraid_gendisk.part[MINOR(bh->b_rdev)].start_sect;	bestsofar = 0; 	bestdist = raid[device].disk[0].last_pos - bh->b_rsector;	if (bestdist<0) 		bestdist=-bestdist;	if (bestdist>4095)		bestdist=4095;