/*   linear.c : Multiple Devices driver for Linux	      Copyright (C) 1994-96 Marc ZYNGIER	      <zyngier@ufr-info-p7.ibp.fr> or	      <maz@gloups.fdn.fr>    Linear mode management functions.    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.*/ #include <linux/blkdev.h>#include <linux/raid/md_u.h>#include <linux/seq_file.h>#include <linux/module.h>#include <linux/slab.h>#include <trace/events/block.h>#include "md.h"#include "linear.h" /* * find which device holds a particular offset */static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector){	int lo, mid, hi;	struct linear_conf *conf; 	lo = 0;	hi = mddev->raid_disks - 1;	conf = mddev->private; 	/*	 * Binary Search	 */ 	while (hi > lo) { 		mid = (hi + lo) / 2;		if (sector < conf->disks[mid].end_sector)			hi = mid;		else			lo = mid + 1;	} 	return conf->disks + lo;} /* * In linear_congested() conf->raid_disks is used as a copy of * mddev->raid_disks to iterate conf->disks[], because conf->raid_disks * and conf->disks[] are created in linear_conf(), they are always * consitent with each other, but mddev->raid_disks does not. */static int linear_congested(struct mddev *mddev, int bits){	struct linear_conf *conf;	int i, ret = 0; 	rcu_read_lock();	conf = rcu_dereference(mddev->private); 	for (i = 0; i < conf->raid_disks && !ret ; i++) {		struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);		ret |= bdi_congested(q->backing_dev_info, bits);	} 	rcu_read_unlock();	return ret;} static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks){	struct linear_conf *conf;	sector_t array_sectors; 	conf = mddev->private;	WARN_ONCE(sectors || raid_disks,		  "%s does not support generic reshape\n", __func__);	array_sectors = conf->array_sectors; 	return array_sectors;} static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks){	struct linear_conf *conf;	struct md_rdev *rdev;	int i, cnt;	bool discard_supported = false; 	conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info),			GFP_KERNEL);	if (!conf)		return NULL; 	cnt = 0;	conf->array_sectors = 0; 	rdev_for_each(rdev, mddev) {		int j = rdev->raid_disk;		struct dev_info *disk = conf->disks + j;		sector_t sectors; 		if (j < 0 || j >= raid_disks || disk->rdev) {			pr_warn("md/linear:%s: disk numbering problem. Aborting!\n",				mdname(mddev));			goto out;		} 		disk->rdev = rdev;		if (mddev->chunk_sectors) {			sectors = rdev->sectors;			sector_div(sectors, mddev->chunk_sectors);			rdev->sectors = sectors * mddev->chunk_sectors;		} 		disk_stack_limits(mddev->gendisk, rdev->bdev,				  rdev->data_offset << 9); 		conf->array_sectors += rdev->sectors;		cnt++; 		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))			discard_supported = true;	}	if (cnt != raid_disks) {		pr_warn("md/linear:%s: not enough drives present. Aborting!\n",			mdname(mddev));		goto out;	} 	if (!discard_supported)		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);	else		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 	/*	 * Here we calculate the device offsets.	 */	conf->disks[0].end_sector = conf->disks[0].rdev->sectors; 	for (i = 1; i < raid_disks; i++)		conf->disks[i].end_sector =			conf->disks[i-1].end_sector +			conf->disks[i].rdev->sectors; 	/*	 * conf->raid_disks is copy of mddev->raid_disks. The reason to	 * keep a copy of mddev->raid_disks in struct linear_conf is,	 * mddev->raid_disks may not be consistent with pointers number of	 * conf->disks[] when it is updated in linear_add() and used to	 * iterate old conf->disks[] earray in linear_congested().	 * Here conf->raid_disks is always consitent with number of	 * pointers in conf->disks[] array, and mddev->private is updated	 * with rcu_assign_pointer() in linear_addr(), such race can be	 * avoided.	 */	conf->raid_disks = raid_disks; 	return conf; out:	kfree(conf);	return NULL;} static int linear_run (struct mddev *mddev){	struct linear_conf *conf;	int ret; 	if (md_check_no_bitmap(mddev))		return -EINVAL;	conf = linear_conf(mddev, mddev->raid_disks); 	if (!conf)		return 1;	mddev->private = conf;	md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); 	ret =  md_integrity_register(mddev);	if (ret) {		kfree(conf);		mddev->private = NULL;	}	return ret;} static int linear_add(struct mddev *mddev, struct md_rdev *rdev){	/* Adding a drive to a linear array allows the array to grow.	 * It is permitted if the new drive has a matching superblock	 * already on it, with raid_disk equal to raid_disks.	 * It is achieved by creating a new linear_private_data structure	 * and swapping it in in-place of the current one.	 * The current one is never freed until the array is stopped.	 * This avoids races.	 */	struct linear_conf *newconf, *oldconf; 	if (rdev->saved_raid_disk != mddev->raid_disks)		return -EINVAL; 	rdev->raid_disk = rdev->saved_raid_disk;	rdev->saved_raid_disk = -1; 	newconf = linear_conf(mddev,mddev->raid_disks+1); 	if (!newconf)		return -ENOMEM; 	/* newconf->raid_disks already keeps a copy of * the increased	 * value of mddev->raid_disks, WARN_ONCE() is just used to make	 * sure of this. It is possible that oldconf is still referenced	 * in linear_congested(), therefore kfree_rcu() is used to free	 * oldconf until no one uses it anymore.	 */	mddev_suspend(mddev);	oldconf = rcu_dereference_protected(mddev->private,			lockdep_is_held(&mddev->reconfig_mutex));	mddev->raid_disks++;	WARN_ONCE(mddev->raid_disks != newconf->raid_disks,		"copied raid_disks doesn't match mddev->raid_disks");	rcu_assign_pointer(mddev->private, newconf);	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));	set_capacity(mddev->gendisk, mddev->array_sectors);	mddev_resume(mddev);	revalidate_disk(mddev->gendisk);	kfree_rcu(oldconf, rcu);	return 0;} static void linear_free(struct mddev *mddev, void *priv){	struct linear_conf *conf = priv; 	kfree(conf);} static bool linear_make_request(struct mddev *mddev, struct bio *bio){	char b[BDEVNAME_SIZE];	struct dev_info *tmp_dev;	sector_t start_sector, end_sector, data_offset;	sector_t bio_sector = bio->bi_iter.bi_sector; 	if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {		md_flush_request(mddev, bio);		return true;	} 	tmp_dev = which_dev(mddev, bio_sector);	start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;	end_sector = tmp_dev->end_sector;	data_offset = tmp_dev->rdev->data_offset; 	if (unlikely(bio_sector >= end_sector ||		     bio_sector < start_sector))		goto out_of_bounds; 	if (unlikely(bio_end_sector(bio) > end_sector)) {		/* This bio crosses a device boundary, so we have to split it */		struct bio *split = bio_split(bio, end_sector - bio_sector,					      GFP_NOIO, mddev->bio_set);		bio_chain(split, bio);		generic_make_request(bio);		bio = split;	} 	bio->bi_bdev = tmp_dev->rdev->bdev;	bio->bi_iter.bi_sector = bio->bi_iter.bi_sector -		start_sector + data_offset; 	if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&		     !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {		/* Just ignore it */		bio_endio(bio);	} else {		if (mddev->gendisk)			trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),					      bio, disk_devt(mddev->gendisk),					      bio_sector);		mddev_check_writesame(mddev, bio);		mddev_check_write_zeroes(mddev, bio);		generic_make_request(bio);	}	return true; out_of_bounds:	pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %s: %llu sectors, offset %llu\n",	       mdname(mddev),	       (unsigned long long)bio->bi_iter.bi_sector,	       bdevname(tmp_dev->rdev->bdev, b),	       (unsigned long long)tmp_dev->rdev->sectors,	       (unsigned long long)start_sector);	bio_io_error(bio);	return true;} static void linear_status (struct seq_file *seq, struct mddev *mddev){	seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);} static void linear_quiesce(struct mddev *mddev, int state){} static struct md_personality linear_personality ={	.name		= "linear",	.level		= LEVEL_LINEAR,	.owner		= THIS_MODULE,	.make_request	= linear_make_request,	.run		= linear_run,	.free		= linear_free,	.status		= linear_status,	.hot_add_disk	= linear_add,	.size		= linear_size,	.quiesce	= linear_quiesce,	.congested	= linear_congested,}; static int __init linear_init (void){	return register_md_personality (&linear_personality);} static void linear_exit (void){	unregister_md_personality (&linear_personality);} module_init(linear_init);module_exit(linear_exit);MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Linear device concatenation personality for MD");MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/MODULE_ALIAS("md-linear");MODULE_ALIAS("md-level--1");