// SPDX-License-Identifier: GPL-2.0-or-later/* * linear.c : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc * ZYNGIER <zyngier@ufr-info-p7.ibp.fr> or <maz@gloups.fdn.fr> */ #include <linux/blkdev.h>#include <linux/seq_file.h>#include <linux/module.h>#include <linux/slab.h>#include <trace/events/block.h>#include "md.h" struct dev_info {	struct md_rdev	*rdev;	sector_t	end_sector;}; struct linear_conf {	struct rcu_head         rcu;	sector_t                array_sectors;	/* a copy of mddev->raid_disks */	int                     raid_disks;	struct dev_info         disks[] __counted_by(raid_disks);}; /* * 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;} 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 int linear_set_limits(struct mddev *mddev){	struct queue_limits lim;	int err; 	md_init_stacking_limits(&lim);	lim.features |= BLK_FEAT_NOWAIT;	lim.max_hw_sectors = mddev->chunk_sectors;	lim.logical_block_size = mddev->logical_block_size;	lim.max_write_zeroes_sectors = mddev->chunk_sectors;	lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors;	lim.io_min = mddev->chunk_sectors << 9;	lim.features |= BLK_FEAT_ATOMIC_WRITES;	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);	if (err)		return err; 	return queue_limits_set(mddev->gendisk->queue, &lim);} static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks){	struct linear_conf *conf;	struct md_rdev *rdev;	int ret = -EINVAL;	int cnt;	int i; 	conf = kzalloc_flex(*conf, disks, raid_disks);	if (!conf)		return ERR_PTR(-ENOMEM); 	/*	 * 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; 	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;		} 		conf->array_sectors += rdev->sectors;		cnt++;	}	if (cnt != raid_disks) {		pr_warn("md/linear:%s: not enough drives present. Aborting!\n",			mdname(mddev));		goto out;	} 	/*	 * 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; 	if (!mddev_is_dm(mddev)) {		ret = linear_set_limits(mddev);		if (ret)			goto out;	} 	return conf; out:	kfree(conf);	return ERR_PTR(ret);} 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 (IS_ERR(conf))		return PTR_ERR(conf); 	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 (IS_ERR(newconf))		return PTR_ERR(newconf); 	/* 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.	 */	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_and_notify(mddev->gendisk, mddev->array_sectors);	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){	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(is_rdev_broken(tmp_dev->rdev))) {		md_error(mddev, tmp_dev->rdev);		bio_io_error(bio);		return true;	} 	if (unlikely(bio_end_sector(bio) > end_sector)) {		/* This bio crosses a device boundary, so we have to split it */		bio = bio_submit_split_bioset(bio, end_sector - bio_sector,					      &mddev->bio_set);		if (!bio)			return true;	} 	md_account_bio(mddev, &bio);	bio_set_dev(bio, 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) &&		     !bdev_max_discard_sectors(bio->bi_bdev))) {		/* Just ignore it */		bio_endio(bio);	} else {		if (mddev->gendisk)			trace_block_bio_remap(bio, disk_devt(mddev->gendisk),					      bio_sector);		mddev_check_write_zeroes(mddev, bio);		submit_bio_noacct(bio);	}	return true; out_of_bounds:	pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %pg: %llu sectors, offset %llu\n",	       mdname(mddev),	       (unsigned long long)bio->bi_iter.bi_sector,	       tmp_dev->rdev->bdev,	       (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_error(struct mddev *mddev, struct md_rdev *rdev){	if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {		char *md_name = mdname(mddev); 		pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n",			md_name, rdev->bdev);	}} static void linear_quiesce(struct mddev *mddev, int state){} static struct md_personality linear_personality = {	.head = {		.type	= MD_PERSONALITY,		.id	= ID_LINEAR,		.name	= "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,	.error_handler	= linear_error,}; static int __init linear_init(void){	return register_md_submodule(&linear_personality.head);} static void linear_exit(void){	unregister_md_submodule(&linear_personality.head);} module_init(linear_init);module_exit(linear_exit);MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)");MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/MODULE_ALIAS("md-linear");MODULE_ALIAS("md-level--1");