Merge tag 'md-next-20231219' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.8/block

Pull MD updates from Song:

"1. Remove deprecated flavors, by Song Liu;
 2. raid1 read error check support, by Li Nan;
 3. Better handle events off-by-1 case, by Alex Lyakas."

* tag 'md-next-20231219' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: Remove deprecated CONFIG_MD_FAULTY
  md: Remove deprecated CONFIG_MD_MULTIPATH
  md: Remove deprecated CONFIG_MD_LINEAR
  md/raid1: support read error check
  md: factor out a helper exceed_read_errors() to check read_errors
  md: Whenassemble the array, consult the superblock of the freshest device
  md/raid1: remove unnecessary null checking

12 files changed, 201 insertions, 1378 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 2a8b081bce7d..f6dc2acdf1ed 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -61,19 +61,6 @@ config MD_BITMAP_FILE
 	  various kernel APIs and can only work with files on a file system not
 	  actually sitting on the MD device.
 
-config MD_LINEAR
-	tristate "Linear (append) mode (deprecated)"
-	depends on BLK_DEV_MD
-	help
-	  If you say Y here, then your multiple devices driver will be able to
-	  use the so-called linear mode, i.e. it will combine the hard disk
-	  partitions by simply appending one to the other.
-
-	  To compile this as a module, choose M here: the module
-	  will be called linear.
-
-	  If unsure, say Y.
-
 config MD_RAID0
 	tristate "RAID-0 (striping) mode"
 	depends on BLK_DEV_MD
@@ -172,27 +159,6 @@ config MD_RAID456
 
 	  If unsure, say Y.
 
-config MD_MULTIPATH
-	tristate "Multipath I/O support (deprecated)"
-	depends on BLK_DEV_MD
-	help
-	  MD_MULTIPATH provides a simple multi-path personality for use
-	  the MD framework.  It is not under active development.  New
-	  projects should consider using DM_MULTIPATH which has more
-	  features and more testing.
-
-	  If unsure, say N.
-
-config MD_FAULTY
-	tristate "Faulty test module for MD (deprecated)"
-	depends on BLK_DEV_MD
-	help
-	  The "faulty" module allows for a block device that occasionally returns
-	  read or write errors.  It is useful for testing.
-
-	  In unsure, say N.
-
-
 config MD_CLUSTER
 	tristate "Cluster Support for MD"
 	depends on BLK_DEV_MD
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 84291e38dca8..027d7cfeca3f 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -29,22 +29,16 @@ dm-zoned-y	+= dm-zoned-target.o dm-zoned-metadata.o dm-zoned-reclaim.o
 
 md-mod-y	+= md.o md-bitmap.o
 raid456-y	+= raid5.o raid5-cache.o raid5-ppl.o
-linear-y	+= md-linear.o
-multipath-y	+= md-multipath.o
-faulty-y	+= md-faulty.o
 
 # Note: link order is important.  All raid personalities
-# and must come before md.o, as they each initialise 
-# themselves, and md.o may use the personalities when it 
+# and must come before md.o, as they each initialise
+# themselves, and md.o may use the personalities when it
 # auto-initialised.
 
-obj-$(CONFIG_MD_LINEAR)		+= linear.o
 obj-$(CONFIG_MD_RAID0)		+= raid0.o
 obj-$(CONFIG_MD_RAID1)		+= raid1.o
 obj-$(CONFIG_MD_RAID10)		+= raid10.o
 obj-$(CONFIG_MD_RAID456)	+= raid456.o
-obj-$(CONFIG_MD_MULTIPATH)	+= multipath.o
-obj-$(CONFIG_MD_FAULTY)		+= faulty.o
 obj-$(CONFIG_MD_CLUSTER)	+= md-cluster.o
 obj-$(CONFIG_BCACHE)		+= bcache/
 obj-$(CONFIG_BLK_DEV_MD)	+= md-mod.o
diff --git a/drivers/md/md-autodetect.c b/drivers/md/md-autodetect.c
index 4b80165afd23..b2a00f213c2c 100644
--- a/drivers/md/md-autodetect.c
+++ b/drivers/md/md-autodetect.c
@@ -49,7 +49,6 @@ static int md_setup_ents __initdata;
  *             instead of just one.  -- KTK
  * 18May2000: Added support for persistent-superblock arrays:
  *             md=n,0,factor,fault,device-list   uses RAID0 for device n
- *             md=n,-1,factor,fault,device-list  uses LINEAR for device n
  *             md=n,device-list      reads a RAID superblock from the devices
  *             elements in device-list are read by name_to_kdev_t so can be
  *             a hex number or something like /dev/hda1 /dev/sdb
@@ -88,7 +87,7 @@ static int __init md_setup(char *str)
 		md_setup_ents++;
 	switch (get_option(&str, &level)) {	/* RAID level */
 	case 2: /* could be 0 or -1.. */
-		if (level == 0 || level == LEVEL_LINEAR) {
+		if (level == 0) {
 			if (get_option(&str, &factor) != 2 ||	/* Chunk Size */
 					get_option(&str, &fault) != 2) {
 				printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
@@ -96,10 +95,7 @@ static int __init md_setup(char *str)
 			}
 			md_setup_args[ent].level = level;
 			md_setup_args[ent].chunk = 1 << (factor+12);
-			if (level ==  LEVEL_LINEAR)
-				pername = "linear";
-			else
-				pername = "raid0";
+			pername = "raid0";
 			break;
 		}
 		fallthrough;
diff --git a/drivers/md/md-faulty.c b/drivers/md/md-faulty.c
deleted file mode 100644
index a039e8e20f55..000000000000
--- a/drivers/md/md-faulty.c
+++ /dev/null
@@ -1,365 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * faulty.c : Multiple Devices driver for Linux
- *
- * Copyright (C) 2004 Neil Brown
- *
- * fautly-device-simulator personality for md
- */
-
-
-/*
- * The "faulty" personality causes some requests to fail.
- *
- * Possible failure modes are:
- *   reads fail "randomly" but succeed on retry
- *   writes fail "randomly" but succeed on retry
- *   reads for some address fail and then persist until a write
- *   reads for some address fail and then persist irrespective of write
- *   writes for some address fail and persist
- *   all writes fail
- *
- * Different modes can be active at a time, but only
- * one can be set at array creation.  Others can be added later.
- * A mode can be one-shot or recurrent with the recurrence being
- * once in every N requests.
- * The bottom 5 bits of the "layout" indicate the mode.  The
- * remainder indicate a period, or 0 for one-shot.
- *
- * There is an implementation limit on the number of concurrently
- * persisting-faulty blocks. When a new fault is requested that would
- * exceed the limit, it is ignored.
- * All current faults can be clear using a layout of "0".
- *
- * Requests are always sent to the device.  If they are to fail,
- * we clone the bio and insert a new b_end_io into the chain.
- */
-
-#define	WriteTransient	0
-#define	ReadTransient	1
-#define	WritePersistent	2
-#define	ReadPersistent	3
-#define	WriteAll	4 /* doesn't go to device */
-#define	ReadFixable	5
-#define	Modes	6
-
-#define	ClearErrors	31
-#define	ClearFaults	30
-
-#define AllPersist	100 /* internal use only */
-#define	NoPersist	101
-
-#define	ModeMask	0x1f
-#define	ModeShift	5
-
-#define MaxFault	50
-#include <linux/blkdev.h>
-#include <linux/module.h>
-#include <linux/raid/md_u.h>
-#include <linux/slab.h>
-#include "md.h"
-#include <linux/seq_file.h>
-
-
-static void faulty_fail(struct bio *bio)
-{
-	struct bio *b = bio->bi_private;
-
-	b->bi_iter.bi_size = bio->bi_iter.bi_size;
-	b->bi_iter.bi_sector = bio->bi_iter.bi_sector;
-
-	bio_put(bio);
-
-	bio_io_error(b);
-}
-
-struct faulty_conf {
-	int period[Modes];
-	atomic_t counters[Modes];
-	sector_t faults[MaxFault];
-	int	modes[MaxFault];
-	int nfaults;
-	struct md_rdev *rdev;
-};
-
-static int check_mode(struct faulty_conf *conf, int mode)
-{
-	if (conf->period[mode] == 0 &&
-	    atomic_read(&conf->counters[mode]) <= 0)
-		return 0; /* no failure, no decrement */
-
-
-	if (atomic_dec_and_test(&conf->counters[mode])) {
-		if (conf->period[mode])
-			atomic_set(&conf->counters[mode], conf->period[mode]);
-		return 1;
-	}
-	return 0;
-}
-
-static int check_sector(struct faulty_conf *conf, sector_t start, sector_t end, int dir)
-{
-	/* If we find a ReadFixable sector, we fix it ... */
-	int i;
-	for (i=0; i<conf->nfaults; i++)
-		if (conf->faults[i] >= start &&
-		    conf->faults[i] < end) {
-			/* found it ... */
-			switch (conf->modes[i] * 2 + dir) {
-			case WritePersistent*2+WRITE: return 1;
-			case ReadPersistent*2+READ: return 1;
-			case ReadFixable*2+READ: return 1;
-			case ReadFixable*2+WRITE:
-				conf->modes[i] = NoPersist;
-				return 0;
-			case AllPersist*2+READ:
-			case AllPersist*2+WRITE: return 1;
-			default:
-				return 0;
-			}
-		}
-	return 0;
-}
-
-static void add_sector(struct faulty_conf *conf, sector_t start, int mode)
-{
-	int i;
-	int n = conf->nfaults;
-	for (i=0; i<conf->nfaults; i++)
-		if (conf->faults[i] == start) {
-			switch(mode) {
-			case NoPersist: conf->modes[i] = mode; return;
-			case WritePersistent:
-				if (conf->modes[i] == ReadPersistent ||
-				    conf->modes[i] == ReadFixable)
-					conf->modes[i] = AllPersist;
-				else
-					conf->modes[i] = WritePersistent;
-				return;
-			case ReadPersistent:
-				if (conf->modes[i] == WritePersistent)
-					conf->modes[i] = AllPersist;
-				else
-					conf->modes[i] = ReadPersistent;
-				return;
-			case ReadFixable:
-				if (conf->modes[i] == WritePersistent ||
-				    conf->modes[i] == ReadPersistent)
-					conf->modes[i] = AllPersist;
-				else
-					conf->modes[i] = ReadFixable;
-				return;
-			}
-		} else if (conf->modes[i] == NoPersist)
-			n = i;
-
-	if (n >= MaxFault)
-		return;
-	conf->faults[n] = start;
-	conf->modes[n] = mode;
-	if (conf->nfaults == n)
-		conf->nfaults = n+1;
-}
-
-static bool faulty_make_request(struct mddev *mddev, struct bio *bio)
-{
-	struct faulty_conf *conf = mddev->private;
-	int failit = 0;
-
-	if (bio_data_dir(bio) == WRITE) {
-		/* write request */
-		if (atomic_read(&conf->counters[WriteAll])) {
-			/* special case - don't decrement, don't submit_bio_noacct,
-			 * just fail immediately
-			 */
-			bio_io_error(bio);
-			return true;
-		}
-
-		if (check_sector(conf, bio->bi_iter.bi_sector,
-				 bio_end_sector(bio), WRITE))
-			failit = 1;
-		if (check_mode(conf, WritePersistent)) {
-			add_sector(conf, bio->bi_iter.bi_sector,
-				   WritePersistent);
-			failit = 1;
-		}
-		if (check_mode(conf, WriteTransient))
-			failit = 1;
-	} else {
-		/* read request */
-		if (check_sector(conf, bio->bi_iter.bi_sector,
-				 bio_end_sector(bio), READ))
-			failit = 1;
-		if (check_mode(conf, ReadTransient))
-			failit = 1;
-		if (check_mode(conf, ReadPersistent)) {
-			add_sector(conf, bio->bi_iter.bi_sector,
-				   ReadPersistent);
-			failit = 1;
-		}
-		if (check_mode(conf, ReadFixable)) {
-			add_sector(conf, bio->bi_iter.bi_sector,
-				   ReadFixable);
-			failit = 1;
-		}
-	}
-
-	md_account_bio(mddev, &bio);
-	if (failit) {
-		struct bio *b = bio_alloc_clone(conf->rdev->bdev, bio, GFP_NOIO,
-						&mddev->bio_set);
-
-		b->bi_private = bio;
-		b->bi_end_io = faulty_fail;
-		bio = b;
-	} else
-		bio_set_dev(bio, conf->rdev->bdev);
-
-	submit_bio_noacct(bio);
-	return true;
-}
-
-static void faulty_status(struct seq_file *seq, struct mddev *mddev)
-{
-	struct faulty_conf *conf = mddev->private;
-	int n;
-
-	if ((n=atomic_read(&conf->counters[WriteTransient])) != 0)
-		seq_printf(seq, " WriteTransient=%d(%d)",
-			   n, conf->period[WriteTransient]);
-
-	if ((n=atomic_read(&conf->counters[ReadTransient])) != 0)
-		seq_printf(seq, " ReadTransient=%d(%d)",
-			   n, conf->period[ReadTransient]);
-
-	if ((n=atomic_read(&conf->counters[WritePersistent])) != 0)
-		seq_printf(seq, " WritePersistent=%d(%d)",
-			   n, conf->period[WritePersistent]);
-
-	if ((n=atomic_read(&conf->counters[ReadPersistent])) != 0)
-		seq_printf(seq, " ReadPersistent=%d(%d)",
-			   n, conf->period[ReadPersistent]);
-
-
-	if ((n=atomic_read(&conf->counters[ReadFixable])) != 0)
-		seq_printf(seq, " ReadFixable=%d(%d)",
-			   n, conf->period[ReadFixable]);
-
-	if ((n=atomic_read(&conf->counters[WriteAll])) != 0)
-		seq_printf(seq, " WriteAll");
-
-	seq_printf(seq, " nfaults=%d", conf->nfaults);
-}
-
-
-static int faulty_reshape(struct mddev *mddev)
-{
-	int mode = mddev->new_layout & ModeMask;
-	int count = mddev->new_layout >> ModeShift;
-	struct faulty_conf *conf = mddev->private;
-
-	if (mddev->new_layout < 0)
-		return 0;
-
-	/* new layout */
-	if (mode == ClearFaults)
-		conf->nfaults = 0;
-	else if (mode == ClearErrors) {
-		int i;
-		for (i=0 ; i < Modes ; i++) {
-			conf->period[i] = 0;
-			atomic_set(&conf->counters[i], 0);
-		}
-	} else if (mode < Modes) {
-		conf->period[mode] = count;
-		if (!count) count++;
-		atomic_set(&conf->counters[mode], count);
-	} else
-		return -EINVAL;
-	mddev->new_layout = -1;
-	mddev->layout = -1; /* makes sure further changes come through */
-	return 0;
-}
-
-static sector_t faulty_size(struct mddev *mddev, sector_t sectors, int raid_disks)
-{
-	WARN_ONCE(raid_disks,
-		  "%s does not support generic reshape\n", __func__);
-
-	if (sectors == 0)
-		return mddev->dev_sectors;
-
-	return sectors;
-}
-
-static int faulty_run(struct mddev *mddev)
-{
-	struct md_rdev *rdev;
-	int i;
-	struct faulty_conf *conf;
-
-	if (md_check_no_bitmap(mddev))
-		return -EINVAL;
-
-	conf = kmalloc(sizeof(*conf), GFP_KERNEL);
-	if (!conf)
-		return -ENOMEM;
-
-	for (i=0; i<Modes; i++) {
-		atomic_set(&conf->counters[i], 0);
-		conf->period[i] = 0;
-	}
-	conf->nfaults = 0;
-
-	rdev_for_each(rdev, mddev) {
-		conf->rdev = rdev;
-		disk_stack_limits(mddev->gendisk, rdev->bdev,
-				  rdev->data_offset << 9);
-	}
-
-	md_set_array_sectors(mddev, faulty_size(mddev, 0, 0));
-	mddev->private = conf;
-
-	faulty_reshape(mddev);
-
-	return 0;
-}
-
-static void faulty_free(struct mddev *mddev, void *priv)
-{
-	struct faulty_conf *conf = priv;
-
-	kfree(conf);
-}
-
-static struct md_personality faulty_personality =
-{
-	.name		= "faulty",
-	.level		= LEVEL_FAULTY,
-	.owner		= THIS_MODULE,
-	.make_request	= faulty_make_request,
-	.run		= faulty_run,
-	.free		= faulty_free,
-	.status		= faulty_status,
-	.check_reshape	= faulty_reshape,
-	.size		= faulty_size,
-};
-
-static int __init raid_init(void)
-{
-	return register_md_personality(&faulty_personality);
-}
-
-static void raid_exit(void)
-{
-	unregister_md_personality(&faulty_personality);
-}
-
-module_init(raid_init);
-module_exit(raid_exit);
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Fault injection personality for MD (deprecated)");
-MODULE_ALIAS("md-personality-10"); /* faulty */
-MODULE_ALIAS("md-faulty");
-MODULE_ALIAS("md-level--5");
diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
deleted file mode 100644
index 8eca7693b793..000000000000
--- a/drivers/md/md-linear.c
+++ /dev/null
@@ -1,318 +0,0 @@
-// 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>
-
-   Linear mode management functions.
-
-*/
-
-#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 "md-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;
-}
-
-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;
-
-	conf = kzalloc(struct_size(conf, disks, raid_disks), GFP_KERNEL);
-	if (!conf)
-		return NULL;
-
-	/*
-	 * 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;
-		}
-
-		disk_stack_limits(mddev->gendisk, rdev->bdev,
-				  rdev->data_offset << 9);
-
-		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;
-
-	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.
-	 */
-	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 */
-		struct bio *split = bio_split(bio, end_sector - bio_sector,
-					      GFP_NOIO, &mddev->bio_set);
-		bio_chain(split, bio);
-		submit_bio_noacct(bio);
-		bio = split;
-	}
-
-	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 =
-{
-	.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,
-	.error_handler	= linear_error,
-};
-
-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 (deprecated)");
-MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
-MODULE_ALIAS("md-linear");
-MODULE_ALIAS("md-level--1");
diff --git a/drivers/md/md-multipath.c b/drivers/md/md-multipath.c
deleted file mode 100644
index 19c8625ea642..000000000000
--- a/drivers/md/md-multipath.c
+++ /dev/null
@@ -1,463 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * multipath.c : Multiple Devices driver for Linux
- *
- * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
- *
- * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
- *
- * MULTIPATH management functions.
- *
- * derived from raid1.c.
- */
-
-#include <linux/blkdev.h>
-#include <linux/module.h>
-#include <linux/raid/md_u.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-#include "md.h"
-#include "md-multipath.h"
-
-#define MAX_WORK_PER_DISK 128
-
-#define	NR_RESERVED_BUFS	32
-
-static int multipath_map (struct mpconf *conf)
-{
-	int i, disks = conf->raid_disks;
-
-	/*
-	 * Later we do read balancing on the read side
-	 * now we use the first available disk.
-	 */
-
-	for (i = 0; i < disks; i++) {
-		struct md_rdev *rdev = conf->multipaths[i].rdev;
-
-		if (rdev && test_bit(In_sync, &rdev->flags) &&
-		    !test_bit(Faulty, &rdev->flags)) {
-			atomic_inc(&rdev->nr_pending);
-			return i;
-		}
-	}
-
-	pr_crit_ratelimited("multipath_map(): no more operational IO paths?\n");
-	return (-1);
-}
-
-static void multipath_reschedule_retry (struct multipath_bh *mp_bh)
-{
-	unsigned long flags;
-	struct mddev *mddev = mp_bh->mddev;
-	struct mpconf *conf = mddev->private;
-
-	spin_lock_irqsave(&conf->device_lock, flags);
-	list_add(&mp_bh->retry_list, &conf->retry_list);
-	spin_unlock_irqrestore(&conf->device_lock, flags);
-	md_wakeup_thread(mddev->thread);
-}
-
-/*
- * multipath_end_bh_io() is called when we have finished servicing a multipathed
- * operation and are ready to return a success/failure code to the buffer
- * cache layer.
- */
-static void multipath_end_bh_io(struct multipath_bh *mp_bh, blk_status_t status)
-{
-	struct bio *bio = mp_bh->master_bio;
-	struct mpconf *conf = mp_bh->mddev->private;
-
-	bio->bi_status = status;
-	bio_endio(bio);
-	mempool_free(mp_bh, &conf->pool);
-}
-
-static void multipath_end_request(struct bio *bio)
-{
-	struct multipath_bh *mp_bh = bio->bi_private;
-	struct mpconf *conf = mp_bh->mddev->private;
-	struct md_rdev *rdev = conf->multipaths[mp_bh->path].rdev;
-
-	if (!bio->bi_status)
-		multipath_end_bh_io(mp_bh, 0);
-	else if (!(bio->bi_opf & REQ_RAHEAD)) {
-		/*
-		 * oops, IO error:
-		 */
-		md_error (mp_bh->mddev, rdev);
-		pr_info("multipath: %pg: rescheduling sector %llu\n",
-			rdev->bdev,
-			(unsigned long long)bio->bi_iter.bi_sector);
-		multipath_reschedule_retry(mp_bh);
-	} else
-		multipath_end_bh_io(mp_bh, bio->bi_status);
-	rdev_dec_pending(rdev, conf->mddev);
-}
-
-static bool multipath_make_request(struct mddev *mddev, struct bio * bio)
-{
-	struct mpconf *conf = mddev->private;
-	struct multipath_bh * mp_bh;
-	struct multipath_info *multipath;
-
-	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
-	    && md_flush_request(mddev, bio))
-		return true;
-
-	md_account_bio(mddev, &bio);
-	mp_bh = mempool_alloc(&conf->pool, GFP_NOIO);
-
-	mp_bh->master_bio = bio;
-	mp_bh->mddev = mddev;
-
-	mp_bh->path = multipath_map(conf);
-	if (mp_bh->path < 0) {
-		bio_io_error(bio);
-		mempool_free(mp_bh, &conf->pool);
-		return true;
-	}
-	multipath = conf->multipaths + mp_bh->path;
-
-	bio_init_clone(multipath->rdev->bdev, &mp_bh->bio, bio, GFP_NOIO);
-
-	mp_bh->bio.bi_iter.bi_sector += multipath->rdev->data_offset;
-	mp_bh->bio.bi_opf |= REQ_FAILFAST_TRANSPORT;
-	mp_bh->bio.bi_end_io = multipath_end_request;
-	mp_bh->bio.bi_private = mp_bh;
-	mddev_check_write_zeroes(mddev, &mp_bh->bio);
-	submit_bio_noacct(&mp_bh->bio);
-	return true;
-}
-
-static void multipath_status(struct seq_file *seq, struct mddev *mddev)
-{
-	struct mpconf *conf = mddev->private;
-	int i;
-
-	lockdep_assert_held(&mddev->lock);
-
-	seq_printf (seq, " [%d/%d] [", conf->raid_disks,
-		    conf->raid_disks - mddev->degraded);
-	for (i = 0; i < conf->raid_disks; i++) {
-		struct md_rdev *rdev = READ_ONCE(conf->multipaths[i].rdev);
-
-		seq_printf(seq, "%s",
-			   rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
-	}
-	seq_putc(seq, ']');
-}
-
-/*
- * Careful, this can execute in IRQ contexts as well!
- */
-static void multipath_error (struct mddev *mddev, struct md_rdev *rdev)
-{
-	struct mpconf *conf = mddev->private;
-
-	if (conf->raid_disks - mddev->degraded <= 1) {
-		/*
-		 * Uh oh, we can do nothing if this is our last path, but
-		 * first check if this is a queued request for a device
-		 * which has just failed.
-		 */
-		pr_warn("multipath: only one IO path left and IO error.\n");
-		/* leave it active... it's all we have */
-		return;
-	}
-	/*
-	 * Mark disk as unusable
-	 */
-	if (test_and_clear_bit(In_sync, &rdev->flags)) {
-		unsigned long flags;
-		spin_lock_irqsave(&conf->device_lock, flags);
-		mddev->degraded++;
-		spin_unlock_irqrestore(&conf->device_lock, flags);
-	}
-	set_bit(Faulty, &rdev->flags);
-	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
-	pr_err("multipath: IO failure on %pg, disabling IO path.\n"
-	       "multipath: Operation continuing on %d IO paths.\n",
-	       rdev->bdev,
-	       conf->raid_disks - mddev->degraded);
-}
-
-static void print_multipath_conf(struct mpconf *conf)
-{
-	int i;
-	struct multipath_info *tmp;
-
-	pr_debug("MULTIPATH conf printout:\n");
-	if (!conf) {
-		pr_debug("(conf==NULL)\n");
-		return;
-	}
-	pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
-		 conf->raid_disks);
-
-	lockdep_assert_held(&conf->mddev->reconfig_mutex);
-	for (i = 0; i < conf->raid_disks; i++) {
-		tmp = conf->multipaths + i;
-		if (tmp->rdev)
-			pr_debug(" disk%d, o:%d, dev:%pg\n",
-				 i,!test_bit(Faulty, &tmp->rdev->flags),
-				 tmp->rdev->bdev);
-	}
-}
-
-static int multipath_add_disk(struct mddev *mddev, struct md_rdev *rdev)
-{
-	struct mpconf *conf = mddev->private;
-	int err = -EEXIST;
-	int path;
-	struct multipath_info *p;
-	int first = 0;
-	int last = mddev->raid_disks - 1;
-
-	if (rdev->raid_disk >= 0)
-		first = last = rdev->raid_disk;
-
-	print_multipath_conf(conf);
-
-	for (path = first; path <= last; path++)
-		if ((p=conf->multipaths+path)->rdev == NULL) {
-			disk_stack_limits(mddev->gendisk, rdev->bdev,
-					  rdev->data_offset << 9);
-
-			err = md_integrity_add_rdev(rdev, mddev);
-			if (err)
-				break;
-			spin_lock_irq(&conf->device_lock);
-			mddev->degraded--;
-			rdev->raid_disk = path;
-			set_bit(In_sync, &rdev->flags);
-			spin_unlock_irq(&conf->device_lock);
-			WRITE_ONCE(p->rdev, rdev);
-			err = 0;
-			break;
-		}
-
-	print_multipath_conf(conf);
-
-	return err;
-}
-
-static int multipath_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
-{
-	struct mpconf *conf = mddev->private;
-	int err = 0;
-	int number = rdev->raid_disk;
-	struct multipath_info *p = conf->multipaths + number;
-
-	print_multipath_conf(conf);
-
-	if (rdev == p->rdev) {
-		if (test_bit(In_sync, &rdev->flags) ||
-		    atomic_read(&rdev->nr_pending)) {
-			pr_warn("hot-remove-disk, slot %d is identified but is still operational!\n", number);
-			err = -EBUSY;
-			goto abort;
-		}
-		WRITE_ONCE(p->rdev, NULL);
-		err = md_integrity_register(mddev);
-	}
-abort:
-
-	print_multipath_conf(conf);
-	return err;
-}
-
-/*
- * This is a kernel thread which:
- *
- *	1.	Retries failed read operations on working multipaths.
- *	2.	Updates the raid superblock when problems encounter.
- *	3.	Performs writes following reads for array syncronising.
- */
-
-static void multipathd(struct md_thread *thread)
-{
-	struct mddev *mddev = thread->mddev;
-	struct multipath_bh *mp_bh;
-	struct bio *bio;
-	unsigned long flags;
-	struct mpconf *conf = mddev->private;
-	struct list_head *head = &conf->retry_list;
-
-	md_check_recovery(mddev);
-	for (;;) {
-		spin_lock_irqsave(&conf->device_lock, flags);
-		if (list_empty(head))
-			break;
-		mp_bh = list_entry(head->prev, struct multipath_bh, retry_list);
-		list_del(head->prev);
-		spin_unlock_irqrestore(&conf->device_lock, flags);
-
-		bio = &mp_bh->bio;
-		bio->bi_iter.bi_sector = mp_bh->master_bio->bi_iter.bi_sector;
-
-		if ((mp_bh->path = multipath_map (conf))<0) {
-			pr_err("multipath: %pg: unrecoverable IO read error for block %llu\n",
-			       bio->bi_bdev,
-			       (unsigned long long)bio->bi_iter.bi_sector);
-			multipath_end_bh_io(mp_bh, BLK_STS_IOERR);
-		} else {
-			pr_err("multipath: %pg: redirecting sector %llu to another IO path\n",
-			       bio->bi_bdev,
-			       (unsigned long long)bio->bi_iter.bi_sector);
-			*bio = *(mp_bh->master_bio);
-			bio->bi_iter.bi_sector +=
-				conf->multipaths[mp_bh->path].rdev->data_offset;
-			bio_set_dev(bio, conf->multipaths[mp_bh->path].rdev->bdev);
-			bio->bi_opf |= REQ_FAILFAST_TRANSPORT;
-			bio->bi_end_io = multipath_end_request;
-			bio->bi_private = mp_bh;
-			submit_bio_noacct(bio);
-		}
-	}
-	spin_unlock_irqrestore(&conf->device_lock, flags);
-}
-
-static sector_t multipath_size(struct mddev *mddev, sector_t sectors, int raid_disks)
-{
-	WARN_ONCE(sectors || raid_disks,
-		  "%s does not support generic reshape\n", __func__);
-
-	return mddev->dev_sectors;
-}
-
-static int multipath_run (struct mddev *mddev)
-{
-	struct mpconf *conf;
-	int disk_idx;
-	struct multipath_info *disk;
-	struct md_rdev *rdev;
-	int working_disks;
-	int ret;
-
-	if (md_check_no_bitmap(mddev))
-		return -EINVAL;
-
-	if (mddev->level != LEVEL_MULTIPATH) {
-		pr_warn("multipath: %s: raid level not set to multipath IO (%d)\n",
-			mdname(mddev), mddev->level);
-		goto out;
-	}
-	/*
-	 * copy the already verified devices into our private MULTIPATH
-	 * bookkeeping area. [whatever we allocate in multipath_run(),
-	 * should be freed in multipath_free()]
-	 */
-
-	conf = kzalloc(sizeof(struct mpconf), GFP_KERNEL);
-	mddev->private = conf;
-	if (!conf)
-		goto out;
-
-	conf->multipaths = kcalloc(mddev->raid_disks,
-				   sizeof(struct multipath_info),
-				   GFP_KERNEL);
-	if (!conf->multipaths)
-		goto out_free_conf;
-
-	working_disks = 0;
-	rdev_for_each(rdev, mddev) {
-		disk_idx = rdev->raid_disk;
-		if (disk_idx < 0 ||
-		    disk_idx >= mddev->raid_disks)
-			continue;
-
-		disk = conf->multipaths + disk_idx;
-		disk->rdev = rdev;
-		disk_stack_limits(mddev->gendisk, rdev->bdev,
-				  rdev->data_offset << 9);
-
-		if (!test_bit(Faulty, &rdev->flags))
-			working_disks++;
-	}
-
-	conf->raid_disks = mddev->raid_disks;
-	conf->mddev = mddev;
-	spin_lock_init(&conf->device_lock);
-	INIT_LIST_HEAD(&conf->retry_list);
-
-	if (!working_disks) {
-		pr_warn("multipath: no operational IO paths for %s\n",
-			mdname(mddev));
-		goto out_free_conf;
-	}
-	mddev->degraded = conf->raid_disks - working_disks;
-
-	ret = mempool_init_kmalloc_pool(&conf->pool, NR_RESERVED_BUFS,
-					sizeof(struct multipath_bh));
-	if (ret)
-		goto out_free_conf;
-
-	rcu_assign_pointer(mddev->thread,
-			   md_register_thread(multipathd, mddev, "multipath"));
-	if (!mddev->thread)
-		goto out_free_conf;
-
-	pr_info("multipath: array %s active with %d out of %d IO paths\n",
-		mdname(mddev), conf->raid_disks - mddev->degraded,
-		mddev->raid_disks);
-	/*
-	 * Ok, everything is just fine now
-	 */
-	md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
-
-	if (md_integrity_register(mddev))
-		goto out_free_conf;
-
-	return 0;
-
-out_free_conf:
-	mempool_exit(&conf->pool);
-	kfree(conf->multipaths);
-	kfree(conf);
-	mddev->private = NULL;
-out:
-	return -EIO;
-}
-
-static void multipath_free(struct mddev *mddev, void *priv)
-{
-	struct mpconf *conf = priv;
-
-	mempool_exit(&conf->pool);
-	kfree(conf->multipaths);
-	kfree(conf);
-}
-
-static struct md_personality multipath_personality =
-{
-	.name		= "multipath",
-	.level		= LEVEL_MULTIPATH,
-	.owner		= THIS_MODULE,
-	.make_request	= multipath_make_request,
-	.run		= multipath_run,
-	.free		= multipath_free,
-	.status		= multipath_status,
-	.error_handler	= multipath_error,
-	.hot_add_disk	= multipath_add_disk,
-	.hot_remove_disk= multipath_remove_disk,
-	.size		= multipath_size,
-};
-
-static int __init multipath_init (void)
-{
-	return register_md_personality (&multipath_personality);
-}
-
-static void __exit multipath_exit (void)
-{
-	unregister_md_personality (&multipath_personality);
-}
-
-module_init(multipath_init);
-module_exit(multipath_exit);
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("simple multi-path personality for MD (deprecated)");
-MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
-MODULE_ALIAS("md-multipath");
-MODULE_ALIAS("md-level--4");
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4e9fe5cbeedc..e351e6c51cc7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1206,6 +1206,7 @@ struct super_type  {
 					  struct md_rdev *refdev,
 					  int minor_version);
 	int		    (*validate_super)(struct mddev *mddev,
+					      struct md_rdev *freshest,
 					      struct md_rdev *rdev);
 	void		    (*sync_super)(struct mddev *mddev,
 					  struct md_rdev *rdev);
@@ -1286,17 +1287,11 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
 	rdev->sb_size = MD_SB_BYTES;
 	rdev->badblocks.shift = -1;
 
-	if (sb->level == LEVEL_MULTIPATH)
-		rdev->desc_nr = -1;
-	else
-		rdev->desc_nr = sb->this_disk.number;
-
-	/* not spare disk, or LEVEL_MULTIPATH */
-	if (sb->level == LEVEL_MULTIPATH ||
-		(rdev->desc_nr >= 0 &&
-		 rdev->desc_nr < MD_SB_DISKS &&
-		 sb->disks[rdev->desc_nr].state &
-		 ((1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE))))
+	rdev->desc_nr = sb->this_disk.number;
+
+	/* not spare disk */
+	if (rdev->desc_nr >= 0 && rdev->desc_nr < MD_SB_DISKS &&
+	    sb->disks[rdev->desc_nr].state & ((1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
 		spare_disk = false;
 
 	if (!refdev) {
@@ -1343,8 +1338,9 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
 
 /*
  * validate_super for 0.90.0
+ * note: we are not using "freshest" for 0.9 superblock
  */
-static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
+static int super_90_validate(struct mddev *mddev, struct md_rdev *freshest, struct md_rdev *rdev)
 {
 	mdp_disk_t *desc;
 	mdp_super_t *sb = page_address(rdev->sb_page);
@@ -1442,31 +1438,28 @@ static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
 			return 0;
 	}
 
-	if (mddev->level != LEVEL_MULTIPATH) {
-		desc = sb->disks + rdev->desc_nr;
+	desc = sb->disks + rdev->desc_nr;
 
-		if (desc->state & (1<<MD_DISK_FAULTY))
-			set_bit(Faulty, &rdev->flags);
-		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
-			    desc->raid_disk < mddev->raid_disks */) {
-			set_bit(In_sync, &rdev->flags);
+	if (desc->state & (1<<MD_DISK_FAULTY))
+		set_bit(Faulty, &rdev->flags);
+	else if (desc->state & (1<<MD_DISK_SYNC)) {
+		set_bit(In_sync, &rdev->flags);
+		rdev->raid_disk = desc->raid_disk;
+		rdev->saved_raid_disk = desc->raid_disk;
+	} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
+		/* active but not in sync implies recovery up to
+		 * reshape position.  We don't know exactly where
+		 * that is, so set to zero for now
+		 */
+		if (mddev->minor_version >= 91) {
+			rdev->recovery_offset = 0;
 			rdev->raid_disk = desc->raid_disk;
-			rdev->saved_raid_disk = desc->raid_disk;
-		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
-			/* active but not in sync implies recovery up to
-			 * reshape position.  We don't know exactly where
-			 * that is, so set to zero for now */
-			if (mddev->minor_version >= 91) {
-				rdev->recovery_offset = 0;
-				rdev->raid_disk = desc->raid_disk;
-			}
 		}
-		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
-			set_bit(WriteMostly, &rdev->flags);
-		if (desc->state & (1<<MD_DISK_FAILFAST))
-			set_bit(FailFast, &rdev->flags);
-	} else /* MULTIPATH are always insync */
-		set_bit(In_sync, &rdev->flags);
+	}
+	if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
+		set_bit(WriteMostly, &rdev->flags);
+	if (desc->state & (1<<MD_DISK_FAILFAST))
+		set_bit(FailFast, &rdev->flags);
 	return 0;
 }
 
@@ -1756,10 +1749,7 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 	    && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
 		return -EINVAL;
 
-	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
-		rdev->desc_nr = -1;
-	else
-		rdev->desc_nr = le32_to_cpu(sb->dev_number);
+	rdev->desc_nr = le32_to_cpu(sb->dev_number);
 
 	if (!rdev->bb_page) {
 		rdev->bb_page = alloc_page(GFP_KERNEL);
@@ -1812,12 +1802,10 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 	    sb->level != 0)
 		return -EINVAL;
 
-	/* not spare disk, or LEVEL_MULTIPATH */
-	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH) ||
-		(rdev->desc_nr >= 0 &&
-		rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
-		(le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < MD_DISK_ROLE_MAX ||
-		 le16_to_cpu(sb->dev_roles[rdev->desc_nr]) == MD_DISK_ROLE_JOURNAL)))
+	/* not spare disk */
+	if (rdev->desc_nr >= 0 && rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
+	    (le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < MD_DISK_ROLE_MAX ||
+	     le16_to_cpu(sb->dev_roles[rdev->desc_nr]) == MD_DISK_ROLE_JOURNAL))
 		spare_disk = false;
 
 	if (!refdev) {
@@ -1856,10 +1844,11 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 	return ret;
 }
 
-static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
+static int super_1_validate(struct mddev *mddev, struct md_rdev *freshest, struct md_rdev *rdev)
 {
 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
 	__u64 ev1 = le64_to_cpu(sb->events);
+	int role;
 
 	rdev->raid_disk = -1;
 	clear_bit(Faulty, &rdev->flags);
@@ -1952,13 +1941,15 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
 		}
 	} else if (mddev->pers == NULL) {
 		/* Insist of good event counter while assembling, except for
-		 * spares (which don't need an event count) */
-		++ev1;
+		 * spares (which don't need an event count).
+		 * Similar to mdadm, we allow event counter difference of 1
+		 * from the freshest device.
+		 */
 		if (rdev->desc_nr >= 0 &&
 		    rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
 		    (le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < MD_DISK_ROLE_MAX ||
 		     le16_to_cpu(sb->dev_roles[rdev->desc_nr]) == MD_DISK_ROLE_JOURNAL))
-			if (ev1 < mddev->events)
+			if (ev1 + 1 < mddev->events)
 				return -EINVAL;
 	} else if (mddev->bitmap) {
 		/* If adding to array with a bitmap, then we can accept an
@@ -1973,58 +1964,85 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
 			/* just a hot-add of a new device, leave raid_disk at -1 */
 			return 0;
 	}
-	if (mddev->level != LEVEL_MULTIPATH) {
-		int role;
-		if (rdev->desc_nr < 0 ||
-		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
-			role = MD_DISK_ROLE_SPARE;
-			rdev->desc_nr = -1;
-		} else
-			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
-		switch(role) {
-		case MD_DISK_ROLE_SPARE: /* spare */
-			break;
-		case MD_DISK_ROLE_FAULTY: /* faulty */
-			set_bit(Faulty, &rdev->flags);
-			break;
-		case MD_DISK_ROLE_JOURNAL: /* journal device */
-			if (!(le32_to_cpu(sb->feature_map) & MD_FEATURE_JOURNAL)) {
-				/* journal device without journal feature */
-				pr_warn("md: journal device provided without journal feature, ignoring the device\n");
-				return -EINVAL;
-			}
-			set_bit(Journal, &rdev->flags);
-			rdev->journal_tail = le64_to_cpu(sb->journal_tail);
-			rdev->raid_disk = 0;
-			break;
-		default:
-			rdev->saved_raid_disk = role;
-			if ((le32_to_cpu(sb->feature_map) &
-			     MD_FEATURE_RECOVERY_OFFSET)) {
-				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
-				if (!(le32_to_cpu(sb->feature_map) &
-				      MD_FEATURE_RECOVERY_BITMAP))
-					rdev->saved_raid_disk = -1;
-			} else {
-				/*
-				 * If the array is FROZEN, then the device can't
-				 * be in_sync with rest of array.
-				 */
-				if (!test_bit(MD_RECOVERY_FROZEN,
-					      &mddev->recovery))
-					set_bit(In_sync, &rdev->flags);
-			}
-			rdev->raid_disk = role;
-			break;
+
+	if (rdev->desc_nr < 0 ||
+	    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
+		role = MD_DISK_ROLE_SPARE;
+		rdev->desc_nr = -1;
+	} else if (mddev->pers == NULL && freshest && ev1 < mddev->events) {
+		/*
+		 * If we are assembling, and our event counter is smaller than the
+		 * highest event counter, we cannot trust our superblock about the role.
+		 * It could happen that our rdev was marked as Faulty, and all other
+		 * superblocks were updated with +1 event counter.
+		 * Then, before the next superblock update, which typically happens when
+		 * remove_and_add_spares() removes the device from the array, there was
+		 * a crash or reboot.
+		 * If we allow current rdev without consulting the freshest superblock,
+		 * we could cause data corruption.
+		 * Note that in this case our event counter is smaller by 1 than the
+		 * highest, otherwise, this rdev would not be allowed into array;
+		 * both kernel and mdadm allow event counter difference of 1.
+		 */
+		struct mdp_superblock_1 *freshest_sb = page_address(freshest->sb_page);
+		u32 freshest_max_dev = le32_to_cpu(freshest_sb->max_dev);
+
+		if (rdev->desc_nr >= freshest_max_dev) {
+			/* this is unexpected, better not proceed */
+			pr_warn("md: %s: rdev[%pg]: desc_nr(%d) >= freshest(%pg)->sb->max_dev(%u)\n",
+				mdname(mddev), rdev->bdev, rdev->desc_nr,
+				freshest->bdev, freshest_max_dev);
+			return -EUCLEAN;
 		}
-		if (sb->devflags & WriteMostly1)
-			set_bit(WriteMostly, &rdev->flags);
-		if (sb->devflags & FailFast1)
-			set_bit(FailFast, &rdev->flags);
-		if (le32_to_cpu(sb->feature_map) & MD_FEATURE_REPLACEMENT)
-			set_bit(Replacement, &rdev->flags);
-	} else /* MULTIPATH are always insync */
-		set_bit(In_sync, &rdev->flags);
+
+		role = le16_to_cpu(freshest_sb->dev_roles[rdev->desc_nr]);
+		pr_debug("md: %s: rdev[%pg]: role=%d(0x%x) according to freshest %pg\n",
+			 mdname(mddev), rdev->bdev, role, role, freshest->bdev);
+	} else {
+		role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
+	}
+	switch (role) {
+	case MD_DISK_ROLE_SPARE: /* spare */
+		break;
+	case MD_DISK_ROLE_FAULTY: /* faulty */
+		set_bit(Faulty, &rdev->flags);
+		break;
+	case MD_DISK_ROLE_JOURNAL: /* journal device */
+		if (!(le32_to_cpu(sb->feature_map) & MD_FEATURE_JOURNAL)) {
+			/* journal device without journal feature */
+			pr_warn("md: journal device provided without journal feature, ignoring the device\n");
+			return -EINVAL;
+		}
+		set_bit(Journal, &rdev->flags);
+		rdev->journal_tail = le64_to_cpu(sb->journal_tail);
+		rdev->raid_disk = 0;
+		break;
+	default:
+		rdev->saved_raid_disk = role;
+		if ((le32_to_cpu(sb->feature_map) &
+		     MD_FEATURE_RECOVERY_OFFSET)) {
+			rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
+			if (!(le32_to_cpu(sb->feature_map) &
+			      MD_FEATURE_RECOVERY_BITMAP))
+				rdev->saved_raid_disk = -1;
+		} else {
+			/*
+			 * If the array is FROZEN, then the device can't
+			 * be in_sync with rest of array.
+			 */
+			if (!test_bit(MD_RECOVERY_FROZEN,
+				      &mddev->recovery))
+				set_bit(In_sync, &rdev->flags);
+		}
+		rdev->raid_disk = role;
+		break;
+	}
+	if (sb->devflags & WriteMostly1)
+		set_bit(WriteMostly, &rdev->flags);
+	if (sb->devflags & FailFast1)
+		set_bit(FailFast, &rdev->flags);
+	if (le32_to_cpu(sb->feature_map) & MD_FEATURE_REPLACEMENT)
+		set_bit(Replacement, &rdev->flags);
 
 	return 0;
 }
@@ -2842,10 +2860,6 @@ rewrite:
 		} else
 			pr_debug("md: %pg (skipping faulty)\n",
 				 rdev->bdev);
-
-		if (mddev->level == LEVEL_MULTIPATH)
-			/* only need to write one superblock... */
-			break;
 	}
 	if (md_super_wait(mddev) < 0)
 		goto rewrite;
@@ -2887,7 +2901,7 @@ static int add_bound_rdev(struct md_rdev *rdev)
 		 * and should be added immediately.
 		 */
 		super_types[mddev->major_version].
-			validate_super(mddev, rdev);
+			validate_super(mddev, NULL/*freshest*/, rdev);
 		err = mddev->pers->hot_add_disk(mddev, rdev);
 		if (err) {
 			md_kick_rdev_from_array(rdev);
@@ -3824,7 +3838,7 @@ static int analyze_sbs(struct mddev *mddev)
 	}
 
 	super_types[mddev->major_version].
-		validate_super(mddev, freshest);
+		validate_super(mddev, NULL/*freshest*/, freshest);
 
 	i = 0;
 	rdev_for_each_safe(rdev, tmp, mddev) {
@@ -3839,20 +3853,15 @@ static int analyze_sbs(struct mddev *mddev)
 		}
 		if (rdev != freshest) {
 			if (super_types[mddev->major_version].
-			    validate_super(mddev, rdev)) {
+			    validate_super(mddev, freshest, rdev)) {
 				pr_warn("md: kicking non-fresh %pg from array!\n",
 					rdev->bdev);
 				md_kick_rdev_from_array(rdev);
 				continue;
 			}
 		}
-		if (mddev->level == LEVEL_MULTIPATH) {
-			rdev->desc_nr = i++;
-			rdev->raid_disk = rdev->desc_nr;
-			set_bit(In_sync, &rdev->flags);
-		} else if (rdev->raid_disk >=
-			    (mddev->raid_disks - min(0, mddev->delta_disks)) &&
-			   !test_bit(Journal, &rdev->flags)) {
+		if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks)) &&
+		    !test_bit(Journal, &rdev->flags)) {
 			rdev->raid_disk = -1;
 			clear_bit(In_sync, &rdev->flags);
 		}
@@ -6847,7 +6856,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 			rdev->saved_raid_disk = rdev->raid_disk;
 		} else
 			super_types[mddev->major_version].
-				validate_super(mddev, rdev);
+				validate_super(mddev, NULL/*freshest*/, rdev);
 		if ((info->state & (1<<MD_DISK_SYNC)) &&
 		     rdev->raid_disk != info->raid_disk) {
 			/* This was a hot-add request, but events doesn't
@@ -8090,7 +8099,7 @@ void md_error(struct mddev *mddev, struct md_rdev *rdev)
 		return;
 	mddev->pers->error_handler(mddev, rdev);
 
-	if (mddev->pers->level == 0 || mddev->pers->level == LEVEL_LINEAR)
+	if (mddev->pers->level == 0)
 		return;
 
 	if (mddev->degraded && !test_bit(MD_BROKEN, &mddev->flags))
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
index 3f22edec70e7..512746551f36 100644
--- a/drivers/md/raid1-10.c
+++ b/drivers/md/raid1-10.c
@@ -173,3 +173,57 @@ static inline void raid1_prepare_flush_writes(struct bitmap *bitmap)
 	else
 		md_bitmap_unplug(bitmap);
 }
+
+/*
+ * Used by fix_read_error() to decay the per rdev read_errors.
+ * We halve the read error count for every hour that has elapsed
+ * since the last recorded read error.
+ */
+static inline void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
+{
+	long cur_time_mon;
+	unsigned long hours_since_last;
+	unsigned int read_errors = atomic_read(&rdev->read_errors);
+
+	cur_time_mon = ktime_get_seconds();
+
+	if (rdev->last_read_error == 0) {
+		/* first time we've seen a read error */
+		rdev->last_read_error = cur_time_mon;
+		return;
+	}
+
+	hours_since_last = (long)(cur_time_mon -
+			    rdev->last_read_error) / 3600;
+
+	rdev->last_read_error = cur_time_mon;
+
+	/*
+	 * if hours_since_last is > the number of bits in read_errors
+	 * just set read errors to 0. We do this to avoid
+	 * overflowing the shift of read_errors by hours_since_last.
+	 */
+	if (hours_since_last >= 8 * sizeof(read_errors))
+		atomic_set(&rdev->read_errors, 0);
+	else
+		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
+}
+
+static inline bool exceed_read_errors(struct mddev *mddev, struct md_rdev *rdev)
+{
+	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
+	int read_errors;
+
+	check_decay_read_errors(mddev, rdev);
+	read_errors =  atomic_inc_return(&rdev->read_errors);
+	if (read_errors > max_read_errors) {
+		pr_notice("md/"RAID_1_10_NAME":%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
+			  mdname(mddev), rdev->bdev, read_errors, max_read_errors);
+		pr_notice("md/"RAID_1_10_NAME":%s: %pg: Failing raid device\n",
+			  mdname(mddev), rdev->bdev);
+		md_error(mddev, rdev);
+		return true;
+	}
+
+	return false;
+}
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 9348f1709512..aaa434f0c175 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -49,6 +49,7 @@ static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
 #define raid1_log(md, fmt, args...)				\
 	do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid1 " fmt, ##args); } while (0)
 
+#define RAID_1_10_NAME "raid1"
 #include "raid1-10.c"
 
 #define START(node) ((node)->start)
@@ -1124,8 +1125,6 @@ static void alloc_behind_master_bio(struct r1bio *r1_bio,
 
 	behind_bio = bio_alloc_bioset(NULL, vcnt, 0, GFP_NOIO,
 				      &r1_bio->mddev->bio_set);
-	if (!behind_bio)
-		return;
 
 	/* discard op, we don't support writezero/writesame yet */
 	if (!bio_has_data(bio)) {
@@ -2257,16 +2256,24 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
  *	3.	Performs writes following reads for array synchronising.
  */
 
-static void fix_read_error(struct r1conf *conf, int read_disk,
-			   sector_t sect, int sectors)
+static void fix_read_error(struct r1conf *conf, struct r1bio *r1_bio)
 {
+	sector_t sect = r1_bio->sector;
+	int sectors = r1_bio->sectors;
+	int read_disk = r1_bio->read_disk;
 	struct mddev *mddev = conf->mddev;
+	struct md_rdev *rdev = rcu_dereference(conf->mirrors[read_disk].rdev);
+
+	if (exceed_read_errors(mddev, rdev)) {
+		r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
+		return;
+	}
+
 	while(sectors) {
 		int s = sectors;
 		int d = read_disk;
 		int success = 0;
 		int start;
-		struct md_rdev *rdev;
 
 		if (s > (PAGE_SIZE>>9))
 			s = PAGE_SIZE >> 9;
@@ -2507,8 +2514,7 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
 	if (mddev->ro == 0
 	    && !test_bit(FailFast, &rdev->flags)) {
 		freeze_array(conf, 1);
-		fix_read_error(conf, r1_bio->read_disk,
-			       r1_bio->sector, r1_bio->sectors);
+		fix_read_error(conf, r1_bio);
 		unfreeze_array(conf);
 	} else if (mddev->ro == 0 && test_bit(FailFast, &rdev->flags)) {
 		md_error(mddev, rdev);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 375c11d6159f..7412066ea22c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -19,6 +19,8 @@
 #include <linux/raid/md_p.h>
 #include <trace/events/block.h>
 #include "md.h"
+
+#define RAID_1_10_NAME "raid10"
 #include "raid10.h"
 #include "raid0.h"
 #include "md-bitmap.h"
@@ -2592,42 +2594,6 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 	}
 }
 
-/*
- * Used by fix_read_error() to decay the per rdev read_errors.
- * We halve the read error count for every hour that has elapsed
- * since the last recorded read error.
- *
- */
-static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
-{
-	long cur_time_mon;
-	unsigned long hours_since_last;
-	unsigned int read_errors = atomic_read(&rdev->read_errors);
-
-	cur_time_mon = ktime_get_seconds();
-
-	if (rdev->last_read_error == 0) {
-		/* first time we've seen a read error */
-		rdev->last_read_error = cur_time_mon;
-		return;
-	}
-
-	hours_since_last = (long)(cur_time_mon -
-			    rdev->last_read_error) / 3600;
-
-	rdev->last_read_error = cur_time_mon;
-
-	/*
-	 * if hours_since_last is > the number of bits in read_errors
-	 * just set read errors to 0. We do this to avoid
-	 * overflowing the shift of read_errors by hours_since_last.
-	 */
-	if (hours_since_last >= 8 * sizeof(read_errors))
-		atomic_set(&rdev->read_errors, 0);
-	else
-		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
-}
-
 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
 			    int sectors, struct page *page, enum req_op op)
 {
@@ -2665,7 +2631,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
 	int sect = 0; /* Offset from r10_bio->sector */
 	int sectors = r10_bio->sectors, slot = r10_bio->read_slot;
 	struct md_rdev *rdev;
-	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
 	int d = r10_bio->devs[slot].devnum;
 
 	/* still own a reference to this rdev, so it cannot
@@ -2678,15 +2643,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
 		   more fix_read_error() attempts */
 		return;
 
-	check_decay_read_errors(mddev, rdev);
-	atomic_inc(&rdev->read_errors);
-	if (atomic_read(&rdev->read_errors) > max_read_errors) {
-		pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
-			  mdname(mddev), rdev->bdev,
-			  atomic_read(&rdev->read_errors), max_read_errors);
-		pr_notice("md/raid10:%s: %pg: Failing raid device\n",
-			  mdname(mddev), rdev->bdev);
-		md_error(mddev, rdev);
+	if (exceed_read_errors(mddev, rdev)) {
 		r10_bio->devs[slot].bio = IO_BLOCKED;
 		return;
 	}
diff --git a/include/uapi/linux/raid/md_p.h b/include/uapi/linux/raid/md_p.h
index 6c0aa577730f..5a43c23f53bf 100644
--- a/include/uapi/linux/raid/md_p.h
+++ b/include/uapi/linux/raid/md_p.h
@@ -2,15 +2,11 @@
 /*
    md_p.h : physical layout of Linux RAID devices
           Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
-	  
+
    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.  
 */
 
 #ifndef _MD_P_H
@@ -237,7 +233,7 @@ struct mdp_superblock_1 {
 	char	set_name[32];	/* set and interpreted by user-space */
 
 	__le64	ctime;		/* lo 40 bits are seconds, top 24 are microseconds or 0*/
-	__le32	level;		/* -4 (multipath), -1 (linear), 0,1,4,5 */
+	__le32	level;		/* 0,1,4,5 */
 	__le32	layout;		/* only for raid5 and raid10 currently */
 	__le64	size;		/* used size of component devices, in 512byte sectors */
 
diff --git a/include/uapi/linux/raid/md_u.h b/include/uapi/linux/raid/md_u.h
index 105307244961..7be89a4906e7 100644
--- a/include/uapi/linux/raid/md_u.h
+++ b/include/uapi/linux/raid/md_u.h
@@ -2,15 +2,11 @@
 /*
    md_u.h : user <=> kernel API between Linux raidtools and RAID drivers
           Copyright (C) 1998 Ingo Molnar
-	  
+
    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.  
 */
 
 #ifndef _UAPI_MD_U_H
@@ -107,11 +103,6 @@ typedef struct mdu_array_info_s {
 
 } mdu_array_info_t;
 
-/* non-obvious values for 'level' */
-#define	LEVEL_MULTIPATH		(-4)
-#define	LEVEL_LINEAR		(-1)
-#define	LEVEL_FAULTY		(-5)
-
 /* we need a value for 'no level specified' and 0
  * means 'raid0', so we need something else.  This is
  * for internal use only