Merge tag 'md/3.20' of git://neil.brown.name/md

Pull md updates from Neil Brown:

 - assorted locking changes so that access to /proc/mdstat
   and much of /sys/block/mdXX/md/* is protected by a spinlock
   rather than a mutex and will never block indefinitely.

 - Make an 'if' condition in RAID5 - which has been implicated
   in recent bugs - more readable.

 - misc minor fixes

* tag 'md/3.20' of git://neil.brown.name/md: (28 commits)
  md/raid10: fix conversion from RAID0 to RAID10
  md: wakeup thread upon rdev_dec_pending()
  md: make reconfig_mutex optional for writes to md sysfs files.
  md: move mddev_lock and related to md.h
  md: use mddev->lock to protect updates to resync_{min,max}.
  md: minor cleanup in safe_delay_store.
  md: move GET_BITMAP_FILE ioctl out from mddev_lock.
  md: tidy up set_bitmap_file
  md: remove unnecessary 'buf' from get_bitmap_file.
  md: remove mddev_lock from rdev_attr_show()
  md: remove mddev_lock() from md_attr_show()
  md/raid5: use ->lock to protect accessing raid5 sysfs attributes.
  md: remove need for mddev_lock() in md_seq_show()
  md/bitmap: protect clearing of ->bitmap by mddev->lock
  md: protect ->pers changes with mddev->lock
  md: level_store: group all important changes into one place.
  md: rename ->stop to ->free
  md: split detach operation out from ->stop.
  md/linear: remove rcu protections in favour of suspend/resume
  md: make merge_bvec_fn more robust in face of personality changes.
  ...

arch/x86/Makefile

@@ -148,6 +148,7 @@ cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTI
 
 # does binutils support specific instructions?
 asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1)
+asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
 asinstr += $(call as-instr,crc32l %eax$(comma)%eax,-DCONFIG_AS_CRC32=1)
 avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
 avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)

drivers/md/bitmap.c

@@ -1619,7 +1619,9 @@ void bitmap_destroy(struct mddev *mddev)
 		return;
 
 	mutex_lock(&mddev->bitmap_info.mutex);
+	spin_lock(&mddev->lock);
 	mddev->bitmap = NULL; /* disconnect from the md device */
+	spin_unlock(&mddev->lock);
 	mutex_unlock(&mddev->bitmap_info.mutex);
 	if (mddev->thread)
 		mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
@@ -2209,11 +2211,13 @@ __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
 static ssize_t can_clear_show(struct mddev *mddev, char *page)
 {
 	int len;
+	spin_lock(&mddev->lock);
 	if (mddev->bitmap)
 		len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
 					     "false" : "true"));
 	else
 		len = sprintf(page, "\n");
+	spin_unlock(&mddev->lock);
 	return len;
 }
 
@@ -2238,10 +2242,15 @@ __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
 static ssize_t
 behind_writes_used_show(struct mddev *mddev, char *page)
 {
+	ssize_t ret;
+	spin_lock(&mddev->lock);
 	if (mddev->bitmap == NULL)
-		return sprintf(page, "0\n");
-	return sprintf(page, "%lu\n",
-		       mddev->bitmap->behind_writes_used);
+		ret = sprintf(page, "0\n");
+	else
+		ret = sprintf(page, "%lu\n",
+			      mddev->bitmap->behind_writes_used);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 static ssize_t

drivers/md/dm-raid.c

@@ -746,13 +746,7 @@ static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
 {
 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
 
-	if (rs->raid_type->level == 1)
-		return md_raid1_congested(&rs->md, bits);
-
-	if (rs->raid_type->level == 10)
-		return md_raid10_congested(&rs->md, bits);
-
-	return md_raid5_congested(&rs->md, bits);
+	return mddev_congested(&rs->md, bits);
 }
 
 /*

drivers/md/faulty.c

@@ -332,13 +332,11 @@ static int run(struct mddev *mddev)
 	return 0;
 }
 
-static int stop(struct mddev *mddev)
+static void faulty_free(struct mddev *mddev, void *priv)
 {
-	struct faulty_conf *conf = mddev->private;
+	struct faulty_conf *conf = priv;
 
 	kfree(conf);
-	mddev->private = NULL;
-	return 0;
 }
 
 static struct md_personality faulty_personality =
@@ -348,7 +346,7 @@ static struct md_personality faulty_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= faulty_free,
 	.status		= status,
 	.check_reshape	= reshape,
 	.size		= faulty_size,

drivers/md/linear.c

@@ -34,7 +34,7 @@ static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
 
 	lo = 0;
 	hi = mddev->raid_disks - 1;
-	conf = rcu_dereference(mddev->private);
+	conf = mddev->private;
 
 	/*
 	 * Binary Search
@@ -60,18 +60,16 @@ static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
  *
  *	Return amount of bytes we can take at this offset
  */
-static int linear_mergeable_bvec(struct request_queue *q,
+static int linear_mergeable_bvec(struct mddev *mddev,
 				 struct bvec_merge_data *bvm,
 				 struct bio_vec *biovec)
 {
-	struct mddev *mddev = q->queuedata;
 	struct dev_info *dev0;
 	unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 	int maxbytes = biovec->bv_len;
 	struct request_queue *subq;
 
-	rcu_read_lock();
 	dev0 = which_dev(mddev, sector);
 	maxsectors = dev0->end_sector - sector;
 	subq = bdev_get_queue(dev0->rdev->bdev);
@@ -81,7 +79,6 @@ static int linear_mergeable_bvec(struct request_queue *q,
 		maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm,
 							     biovec));
 	}
-	rcu_read_unlock();
 
 	if (maxsectors < bio_sectors)
 		maxsectors = 0;
@@ -97,24 +94,18 @@ static int linear_mergeable_bvec(struct request_queue *q,
 		return maxsectors << 9;
 }
 
-static int linear_congested(void *data, int bits)
+static int linear_congested(struct mddev *mddev, int bits)
 {
-	struct mddev *mddev = data;
 	struct linear_conf *conf;
 	int i, ret = 0;
 
-	if (mddev_congested(mddev, bits))
-		return 1;
-
-	rcu_read_lock();
-	conf = rcu_dereference(mddev->private);
+	conf = mddev->private;
 
 	for (i = 0; i < mddev->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;
 }
 
@@ -123,12 +114,10 @@ static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disk
 	struct linear_conf *conf;
 	sector_t array_sectors;
 
-	rcu_read_lock();
-	conf = rcu_dereference(mddev->private);
+	conf = mddev->private;
 	WARN_ONCE(sectors || raid_disks,
 		  "%s does not support generic reshape\n", __func__);
 	array_sectors = conf->array_sectors;
-	rcu_read_unlock();
 
 	return array_sectors;
 }
@@ -217,10 +206,6 @@ static int linear_run (struct mddev *mddev)
 	mddev->private = conf;
 	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
 
-	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
-	mddev->queue->backing_dev_info.congested_fn = linear_congested;
-	mddev->queue->backing_dev_info.congested_data = mddev;
-
 	ret =  md_integrity_register(mddev);
 	if (ret) {
 		kfree(conf);
@@ -252,38 +237,23 @@ static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
 	if (!newconf)
 		return -ENOMEM;
 
-	oldconf = rcu_dereference_protected(mddev->private,
-					    lockdep_is_held(
-						    &mddev->reconfig_mutex));
+	mddev_suspend(mddev);
+	oldconf = mddev->private;
 	mddev->raid_disks++;
-	rcu_assign_pointer(mddev->private, newconf);
+	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);
+	kfree(oldconf);
 	return 0;
 }
 
-static int linear_stop (struct mddev *mddev)
+static void linear_free(struct mddev *mddev, void *priv)
 {
-	struct linear_conf *conf =
-		rcu_dereference_protected(mddev->private,
-					  lockdep_is_held(
-						  &mddev->reconfig_mutex));
+	struct linear_conf *conf = priv;
 
-	/*
-	 * We do not require rcu protection here since
-	 * we hold reconfig_mutex for both linear_add and
-	 * linear_stop, so they cannot race.
-	 * We should make sure any old 'conf's are properly
-	 * freed though.
-	 */
-	rcu_barrier();
-	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	kfree(conf);
-	mddev->private = NULL;
-
-	return 0;
 }
 
 static void linear_make_request(struct mddev *mddev, struct bio *bio)
@@ -299,16 +269,12 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
 	}
 
 	do {
-		rcu_read_lock();
-
 		tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector);
 		start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
 		end_sector = tmp_dev->end_sector;
 		data_offset = tmp_dev->rdev->data_offset;
 		bio->bi_bdev = tmp_dev->rdev->bdev;
 
-		rcu_read_unlock();
-
 		if (unlikely(bio->bi_iter.bi_sector >= end_sector ||
 			     bio->bi_iter.bi_sector < start_sector))
 			goto out_of_bounds;
@@ -355,6 +321,10 @@ 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",
@@ -362,10 +332,13 @@ static struct md_personality linear_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= linear_make_request,
 	.run		= linear_run,
-	.stop		= linear_stop,
+	.free		= linear_free,
 	.status		= linear_status,
 	.hot_add_disk	= linear_add,
 	.size		= linear_size,
+	.quiesce	= linear_quiesce,
+	.congested	= linear_congested,
+	.mergeable_bvec	= linear_mergeable_bvec,
 };
 
 static int __init linear_init (void)

drivers/md/md.h

@@ -386,7 +386,18 @@ struct mddev {
 
 	struct work_struct del_work;	/* used for delayed sysfs removal */
 
-	spinlock_t			write_lock;
+	/* "lock" protects:
+	 *   flush_bio transition from NULL to !NULL
+	 *   rdev superblocks, events
+	 *   clearing MD_CHANGE_*
+	 *   in_sync - and related safemode and MD_CHANGE changes
+	 *   pers (also protected by reconfig_mutex and pending IO).
+	 *   clearing ->bitmap
+	 *   clearing ->bitmap_info.file
+	 *   changing ->resync_{min,max}
+	 *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
+	 */
+	spinlock_t			lock;
 	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
 	atomic_t			pending_writes;	/* number of active superblock writes */
 
@@ -439,13 +450,30 @@ struct mddev {
 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 };
 
-static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
+static inline int __must_check mddev_lock(struct mddev *mddev)
 {
-	int faulty = test_bit(Faulty, &rdev->flags);
-	if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
-		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	return mutex_lock_interruptible(&mddev->reconfig_mutex);
+}
+
+/* Sometimes we need to take the lock in a situation where
+ * failure due to interrupts is not acceptable.
+ */
+static inline void mddev_lock_nointr(struct mddev *mddev)
+{
+	mutex_lock(&mddev->reconfig_mutex);
+}
+
+static inline int mddev_is_locked(struct mddev *mddev)
+{
+	return mutex_is_locked(&mddev->reconfig_mutex);
 }
 
+static inline int mddev_trylock(struct mddev *mddev)
+{
+	return mutex_trylock(&mddev->reconfig_mutex);
+}
+extern void mddev_unlock(struct mddev *mddev);
+
 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 {
 	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
@@ -459,7 +487,7 @@ struct md_personality
 	struct module *owner;
 	void (*make_request)(struct mddev *mddev, struct bio *bio);
 	int (*run)(struct mddev *mddev);
-	int (*stop)(struct mddev *mddev);
+	void (*free)(struct mddev *mddev, void *priv);
 	void (*status)(struct seq_file *seq, struct mddev *mddev);
 	/* error_handler must set ->faulty and clear ->in_sync
 	 * if appropriate, and should abort recovery if needed
@@ -490,6 +518,13 @@ struct md_personality
 	 * array.
 	 */
 	void *(*takeover) (struct mddev *mddev);
+	/* congested implements bdi.congested_fn().
+	 * Will not be called while array is 'suspended' */
+	int (*congested)(struct mddev *mddev, int bits);
+	/* mergeable_bvec is use to implement ->merge_bvec_fn */
+	int (*mergeable_bvec)(struct mddev *mddev,
+			      struct bvec_merge_data *bvm,
+			      struct bio_vec *biovec);
 };
 
 struct md_sysfs_entry {
@@ -624,4 +659,14 @@ static inline int mddev_check_plugged(struct mddev *mddev)
 	return !!blk_check_plugged(md_unplug, mddev,
 				   sizeof(struct blk_plug_cb));
 }
+
+static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
+{
+	int faulty = test_bit(Faulty, &rdev->flags);
+	if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		md_wakeup_thread(mddev->thread);
+	}
+}
+
 #endif /* _MD_MD_H */

drivers/md/multipath.c

@@ -153,15 +153,11 @@ static void multipath_status (struct seq_file *seq, struct mddev *mddev)
 	seq_printf (seq, "]");
 }
 
-static int multipath_congested(void *data, int bits)
+static int multipath_congested(struct mddev *mddev, int bits)
 {
-	struct mddev *mddev = data;
 	struct mpconf *conf = mddev->private;
 	int i, ret = 0;
 
-	if (mddev_congested(mddev, bits))
-		return 1;
-
 	rcu_read_lock();
 	for (i = 0; i < mddev->raid_disks ; i++) {
 		struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
@@ -403,7 +399,7 @@ static int multipath_run (struct mddev *mddev)
 	/*
 	 * copy the already verified devices into our private MULTIPATH
 	 * bookkeeping area. [whatever we allocate in multipath_run(),
-	 * should be freed in multipath_stop()]
+	 * should be freed in multipath_free()]
 	 */
 
 	conf = kzalloc(sizeof(struct mpconf), GFP_KERNEL);
@@ -489,9 +485,6 @@ static int multipath_run (struct mddev *mddev)
 	 */
 	md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
 
-	mddev->queue->backing_dev_info.congested_fn = multipath_congested;
-	mddev->queue->backing_dev_info.congested_data = mddev;
-
 	if (md_integrity_register(mddev))
 		goto out_free_conf;
 
@@ -507,17 +500,13 @@ static int multipath_run (struct mddev *mddev)
 	return -EIO;
 }
 
-static int multipath_stop (struct mddev *mddev)
+static void multipath_free(struct mddev *mddev, void *priv)
 {
-	struct mpconf *conf = mddev->private;
+	struct mpconf *conf = priv;
 
-	md_unregister_thread(&mddev->thread);
-	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	mempool_destroy(conf->pool);
 	kfree(conf->multipaths);
 	kfree(conf);
-	mddev->private = NULL;
-	return 0;
 }
 
 static struct md_personality multipath_personality =
@@ -527,12 +516,13 @@ static struct md_personality multipath_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= multipath_make_request,
 	.run		= multipath_run,
-	.stop		= multipath_stop,
+	.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,
+	.congested	= multipath_congested,
 };
 
 static int __init multipath_init (void)

drivers/md/raid0.c

@@ -25,17 +25,13 @@
 #include "raid0.h"
 #include "raid5.h"
 
-static int raid0_congested(void *data, int bits)
+static int raid0_congested(struct mddev *mddev, int bits)
 {
-	struct mddev *mddev = data;
 	struct r0conf *conf = mddev->private;
 	struct md_rdev **devlist = conf->devlist;
 	int raid_disks = conf->strip_zone[0].nb_dev;
 	int i, ret = 0;
 
-	if (mddev_congested(mddev, bits))
-		return 1;
-
 	for (i = 0; i < raid_disks && !ret ; i++) {
 		struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
 
@@ -263,8 +259,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 			 mdname(mddev),
 			 (unsigned long long)smallest->sectors);
 	}
-	mddev->queue->backing_dev_info.congested_fn = raid0_congested;
-	mddev->queue->backing_dev_info.congested_data = mddev;
 
 	/*
 	 * now since we have the hard sector sizes, we can make sure
@@ -356,17 +350,16 @@ static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
 
 /**
  *	raid0_mergeable_bvec -- tell bio layer if two requests can be merged
- *	@q: request queue
+ *	@mddev: the md device
  *	@bvm: properties of new bio
  *	@biovec: the request that could be merged to it.
  *
  *	Return amount of bytes we can accept at this offset
  */
-static int raid0_mergeable_bvec(struct request_queue *q,
+static int raid0_mergeable_bvec(struct mddev *mddev,
 				struct bvec_merge_data *bvm,
 				struct bio_vec *biovec)
 {
-	struct mddev *mddev = q->queuedata;
 	struct r0conf *conf = mddev->private;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 	sector_t sector_offset = sector;
@@ -422,7 +415,7 @@ static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks
 	return array_sectors;
 }
 
-static int raid0_stop(struct mddev *mddev);
+static void raid0_free(struct mddev *mddev, void *priv);
 
 static int raid0_run(struct mddev *mddev)
 {
@@ -471,26 +464,22 @@ static int raid0_run(struct mddev *mddev)
 			mddev->queue->backing_dev_info.ra_pages = 2* stripe;
 	}
 
-	blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
 	dump_zones(mddev);
 
 	ret = md_integrity_register(mddev);
 	if (ret)
-		raid0_stop(mddev);
+		raid0_free(mddev, conf);
 
 	return ret;
 }
 
-static int raid0_stop(struct mddev *mddev)
+static void raid0_free(struct mddev *mddev, void *priv)
 {
-	struct r0conf *conf = mddev->private;
+	struct r0conf *conf = priv;
 
-	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	kfree(conf->strip_zone);
 	kfree(conf->devlist);
 	kfree(conf);
-	mddev->private = NULL;
-	return 0;
 }
 
 /*
@@ -724,11 +713,13 @@ static struct md_personality raid0_personality=
 	.owner		= THIS_MODULE,
 	.make_request	= raid0_make_request,
 	.run		= raid0_run,
-	.stop		= raid0_stop,
+	.free		= raid0_free,
 	.status		= raid0_status,
 	.size		= raid0_size,
 	.takeover	= raid0_takeover,
 	.quiesce	= raid0_quiesce,
+	.congested	= raid0_congested,
+	.mergeable_bvec	= raid0_mergeable_bvec,
 };
 
 static int __init raid0_init (void)

drivers/md/raid1.c

@@ -701,11 +701,10 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
 	return best_disk;
 }
 
-static int raid1_mergeable_bvec(struct request_queue *q,
+static int raid1_mergeable_bvec(struct mddev *mddev,
 				struct bvec_merge_data *bvm,
 				struct bio_vec *biovec)
 {
-	struct mddev *mddev = q->queuedata;
 	struct r1conf *conf = mddev->private;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 	int max = biovec->bv_len;
@@ -734,7 +733,7 @@ static int raid1_mergeable_bvec(struct request_queue *q,
 
 }
 
-int md_raid1_congested(struct mddev *mddev, int bits)
+static int raid1_congested(struct mddev *mddev, int bits)
 {
 	struct r1conf *conf = mddev->private;
 	int i, ret = 0;
@@ -763,15 +762,6 @@ int md_raid1_congested(struct mddev *mddev, int bits)
 	rcu_read_unlock();
 	return ret;
 }
-EXPORT_SYMBOL_GPL(md_raid1_congested);
-
-static int raid1_congested(void *data, int bits)
-{
-	struct mddev *mddev = data;
-
-	return mddev_congested(mddev, bits) ||
-		md_raid1_congested(mddev, bits);
-}
 
 static void flush_pending_writes(struct r1conf *conf)
 {
@@ -2882,7 +2872,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
 	return ERR_PTR(err);
 }
 
-static int stop(struct mddev *mddev);
+static void raid1_free(struct mddev *mddev, void *priv);
 static int run(struct mddev *mddev)
 {
 	struct r1conf *conf;
@@ -2904,7 +2894,7 @@ static int run(struct mddev *mddev)
 	/*
 	 * copy the already verified devices into our private RAID1
 	 * bookkeeping area. [whatever we allocate in run(),
-	 * should be freed in stop()]
+	 * should be freed in raid1_free()]
 	 */
 	if (mddev->private == NULL)
 		conf = setup_conf(mddev);
@@ -2955,10 +2945,6 @@ static int run(struct mddev *mddev)
 	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
 
 	if (mddev->queue) {
-		mddev->queue->backing_dev_info.congested_fn = raid1_congested;
-		mddev->queue->backing_dev_info.congested_data = mddev;
-		blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
-
 		if (discard_supported)
 			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
 						mddev->queue);
@@ -2968,37 +2954,23 @@ static int run(struct mddev *mddev)
 	}
 
 	ret =  md_integrity_register(mddev);
-	if (ret)
-		stop(mddev);
+	if (ret) {
+		md_unregister_thread(&mddev->thread);
+		raid1_free(mddev, conf);
+	}
 	return ret;
 }
 
-static int stop(struct mddev *mddev)
+static void raid1_free(struct mddev *mddev, void *priv)
 {
-	struct r1conf *conf = mddev->private;
-	struct bitmap *bitmap = mddev->bitmap;
+	struct r1conf *conf = priv;
 
-	/* wait for behind writes to complete */
-	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
-		printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
-		       mdname(mddev));
-		/* need to kick something here to make sure I/O goes? */
-		wait_event(bitmap->behind_wait,
-			   atomic_read(&bitmap->behind_writes) == 0);
-	}
-
-	freeze_array(conf, 0);
-	unfreeze_array(conf);
-
-	md_unregister_thread(&mddev->thread);
 	if (conf->r1bio_pool)
 		mempool_destroy(conf->r1bio_pool);
 	kfree(conf->mirrors);
 	safe_put_page(conf->tmppage);
 	kfree(conf->poolinfo);
 	kfree(conf);
-	mddev->private = NULL;
-	return 0;
 }
 
 static int raid1_resize(struct mddev *mddev, sector_t sectors)
@@ -3181,7 +3153,7 @@ static struct md_personality raid1_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= raid1_free,
 	.status		= status,
 	.error_handler	= error,
 	.hot_add_disk	= raid1_add_disk,
@@ -3193,6 +3165,8 @@ static struct md_personality raid1_personality =
 	.check_reshape	= raid1_reshape,
 	.quiesce	= raid1_quiesce,
 	.takeover	= raid1_takeover,
+	.congested	= raid1_congested,
+	.mergeable_bvec	= raid1_mergeable_bvec,
 };
 
 static int __init raid_init(void)

drivers/md/raid1.h

@@ -170,7 +170,4 @@ struct r1bio {
  */
 #define	R1BIO_MadeGood 7
 #define	R1BIO_WriteError 8
-
-extern int md_raid1_congested(struct mddev *mddev, int bits);
-
 #endif

drivers/md/raid10.c

@@ -674,7 +674,7 @@ static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 
 /**
  *	raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
- *	@q: request queue
+ *	@mddev: the md device
  *	@bvm: properties of new bio
  *	@biovec: the request that could be merged to it.
  *
@@ -682,11 +682,10 @@ static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
  *	This requires checking for end-of-chunk if near_copies != raid_disks,
  *	and for subordinate merge_bvec_fns if merge_check_needed.
  */
-static int raid10_mergeable_bvec(struct request_queue *q,
+static int raid10_mergeable_bvec(struct mddev *mddev,
 				 struct bvec_merge_data *bvm,
 				 struct bio_vec *biovec)
 {
-	struct mddev *mddev = q->queuedata;
 	struct r10conf *conf = mddev->private;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 	int max;
@@ -910,7 +909,7 @@ static struct md_rdev *read_balance(struct r10conf *conf,
 	return rdev;
 }
 
-int md_raid10_congested(struct mddev *mddev, int bits)
+static int raid10_congested(struct mddev *mddev, int bits)
 {
 	struct r10conf *conf = mddev->private;
 	int i, ret = 0;
@@ -934,15 +933,6 @@ int md_raid10_congested(struct mddev *mddev, int bits)
 	rcu_read_unlock();
 	return ret;
 }
-EXPORT_SYMBOL_GPL(md_raid10_congested);
-
-static int raid10_congested(void *data, int bits)
-{
-	struct mddev *mddev = data;
-
-	return mddev_congested(mddev, bits) ||
-		md_raid10_congested(mddev, bits);
-}
 
 static void flush_pending_writes(struct r10conf *conf)
 {
@@ -3757,8 +3747,6 @@ static int run(struct mddev *mddev)
 	if (mddev->queue) {
 		int stripe = conf->geo.raid_disks *
 			((mddev->chunk_sectors << 9) / PAGE_SIZE);
-		mddev->queue->backing_dev_info.congested_fn = raid10_congested;
-		mddev->queue->backing_dev_info.congested_data = mddev;
 
 		/* Calculate max read-ahead size.
 		 * We need to readahead at least twice a whole stripe....
@@ -3767,7 +3755,6 @@ static int run(struct mddev *mddev)
 		stripe /= conf->geo.near_copies;
 		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
 			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
-		blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
 	}
 
 	if (md_integrity_register(mddev))
@@ -3811,17 +3798,9 @@ static int run(struct mddev *mddev)
 	return -EIO;
 }
 
-static int stop(struct mddev *mddev)
+static void raid10_free(struct mddev *mddev, void *priv)
 {
-	struct r10conf *conf = mddev->private;
-
-	raise_barrier(conf, 0);
-	lower_barrier(conf);
-
-	md_unregister_thread(&mddev->thread);
-	if (mddev->queue)
-		/* the unplug fn references 'conf'*/
-		blk_sync_queue(mddev->queue);
+	struct r10conf *conf = priv;
 
 	if (conf->r10bio_pool)
 		mempool_destroy(conf->r10bio_pool);
@@ -3830,8 +3809,6 @@ static int stop(struct mddev *mddev)
 	kfree(conf->mirrors_old);
 	kfree(conf->mirrors_new);
 	kfree(conf);
-	mddev->private = NULL;
-	return 0;
 }
 
 static void raid10_quiesce(struct mddev *mddev, int state)
@@ -3895,7 +3872,7 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
 	return 0;
 }
 
-static void *raid10_takeover_raid0(struct mddev *mddev)
+static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
 {
 	struct md_rdev *rdev;
 	struct r10conf *conf;
@@ -3905,6 +3882,7 @@ static void *raid10_takeover_raid0(struct mddev *mddev)
 		       mdname(mddev));
 		return ERR_PTR(-EINVAL);
 	}
+	sector_div(size, devs);
 
 	/* Set new parameters */
 	mddev->new_level = 10;
@@ -3915,12 +3893,15 @@ static void *raid10_takeover_raid0(struct mddev *mddev)
 	mddev->raid_disks *= 2;
 	/* make sure it will be not marked as dirty */
 	mddev->recovery_cp = MaxSector;
+	mddev->dev_sectors = size;
 
 	conf = setup_conf(mddev);
 	if (!IS_ERR(conf)) {
 		rdev_for_each(rdev, mddev)
-			if (rdev->raid_disk >= 0)
+			if (rdev->raid_disk >= 0) {
 				rdev->new_raid_disk = rdev->raid_disk * 2;
+				rdev->sectors = size;
+			}
 		conf->barrier = 1;
 	}
 
@@ -3943,7 +3924,9 @@ static void *raid10_takeover(struct mddev *mddev)
 			       mdname(mddev));
 			return ERR_PTR(-EINVAL);
 		}
-		return raid10_takeover_raid0(mddev);
+		return raid10_takeover_raid0(mddev,
+			raid0_conf->strip_zone->zone_end,
+			raid0_conf->strip_zone->nb_dev);
 	}
 	return ERR_PTR(-EINVAL);
 }
@@ -4713,7 +4696,7 @@ static struct md_personality raid10_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= raid10_free,
 	.status		= status,
 	.error_handler	= error,
 	.hot_add_disk	= raid10_add_disk,
@@ -4727,6 +4710,8 @@ static struct md_personality raid10_personality =
 	.check_reshape	= raid10_check_reshape,
 	.start_reshape	= raid10_start_reshape,
 	.finish_reshape	= raid10_finish_reshape,
+	.congested	= raid10_congested,
+	.mergeable_bvec	= raid10_mergeable_bvec,
 };
 
 static int __init raid_init(void)

drivers/md/raid10.h

@@ -150,7 +150,4 @@ enum r10bio_state {
  */
 	R10BIO_Previous,
 };
-
-extern int md_raid10_congested(struct mddev *mddev, int bits);
-
 #endif

drivers/md/raid5.c

@@ -296,12 +296,9 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 	BUG_ON(atomic_read(&conf->active_stripes)==0);
 	if (test_bit(STRIPE_HANDLE, &sh->state)) {
 		if (test_bit(STRIPE_DELAYED, &sh->state) &&
-		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 			list_add_tail(&sh->lru, &conf->delayed_list);
-			if (atomic_read(&conf->preread_active_stripes)
-			    < IO_THRESHOLD)
-				md_wakeup_thread(conf->mddev->thread);
-		} else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
+		else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 			   sh->bm_seq - conf->seq_write > 0)
 			list_add_tail(&sh->lru, &conf->bitmap_list);
 		else {
@@ -2898,31 +2895,102 @@ static int want_replace(struct stripe_head *sh, int disk_idx)
  * Returns 1 when no more member devices need to be checked, otherwise returns
  * 0 to tell the loop in handle_stripe_fill to continue
  */
-static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
-		       int disk_idx, int disks)
+
+static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
+			   int disk_idx, int disks)
 {
 	struct r5dev *dev = &sh->dev[disk_idx];
 	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
 				  &sh->dev[s->failed_num[1]] };
+	int i;
+
+
+	if (test_bit(R5_LOCKED, &dev->flags) ||
+	    test_bit(R5_UPTODATE, &dev->flags))
+		/* No point reading this as we already have it or have
+		 * decided to get it.
+		 */
+		return 0;
+
+	if (dev->toread ||
+	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
+		/* We need this block to directly satisfy a request */
+		return 1;
+
+	if (s->syncing || s->expanding ||
+	    (s->replacing && want_replace(sh, disk_idx)))
+		/* When syncing, or expanding we read everything.
+		 * When replacing, we need the replaced block.
+		 */
+		return 1;
+
+	if ((s->failed >= 1 && fdev[0]->toread) ||
+	    (s->failed >= 2 && fdev[1]->toread))
+		/* If we want to read from a failed device, then
+		 * we need to actually read every other device.
+		 */
+		return 1;
+
+	/* Sometimes neither read-modify-write nor reconstruct-write
+	 * cycles can work.  In those cases we read every block we
+	 * can.  Then the parity-update is certain to have enough to
+	 * work with.
+	 * This can only be a problem when we need to write something,
+	 * and some device has failed.  If either of those tests
+	 * fail we need look no further.
+	 */
+	if (!s->failed || !s->to_write)
+		return 0;
+
+	if (test_bit(R5_Insync, &dev->flags) &&
+	    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+		/* Pre-reads at not permitted until after short delay
+		 * to gather multiple requests.  However if this
+		 * device is no Insync, the block could only be be computed
+		 * and there is no need to delay that.
+		 */
+		return 0;
+
+	for (i = 0; i < s->failed; i++) {
+		if (fdev[i]->towrite &&
+		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
+		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
+			/* If we have a partial write to a failed
+			 * device, then we will need to reconstruct
+			 * the content of that device, so all other
+			 * devices must be read.
+			 */
+			return 1;
+	}
+
+	/* If we are forced to do a reconstruct-write, either because
+	 * the current RAID6 implementation only supports that, or
+	 * or because parity cannot be trusted and we are currently
+	 * recovering it, there is extra need to be careful.
+	 * If one of the devices that we would need to read, because
+	 * it is not being overwritten (and maybe not written at all)
+	 * is missing/faulty, then we need to read everything we can.
+	 */
+	if (sh->raid_conf->level != 6 &&
+	    sh->sector < sh->raid_conf->mddev->recovery_cp)
+		/* reconstruct-write isn't being forced */
+		return 0;
+	for (i = 0; i < s->failed; i++) {
+		if (!test_bit(R5_UPTODATE, &fdev[i]->flags) &&
+		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
+		       int disk_idx, int disks)
+{
+	struct r5dev *dev = &sh->dev[disk_idx];
 
 	/* is the data in this block needed, and can we get it? */
-	if (!test_bit(R5_LOCKED, &dev->flags) &&
-	    !test_bit(R5_UPTODATE, &dev->flags) &&
-	    (dev->toread ||
-	     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
-	     s->syncing || s->expanding ||
-	     (s->replacing && want_replace(sh, disk_idx)) ||
-	     (s->failed >= 1 && fdev[0]->toread) ||
-	     (s->failed >= 2 && fdev[1]->toread) ||
-	     (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
-	      (!test_bit(R5_Insync, &dev->flags) || test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) &&
-	      !test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
-	     ((sh->raid_conf->level == 6 ||
-	       sh->sector >= sh->raid_conf->mddev->recovery_cp)
-	      && s->failed && s->to_write &&
-	      (s->to_write - s->non_overwrite <
-	       sh->raid_conf->raid_disks - sh->raid_conf->max_degraded) &&
-	      (!test_bit(R5_Insync, &dev->flags) || test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))))) {
+	if (need_this_block(sh, s, disk_idx, disks)) {
 		/* we would like to get this block, possibly by computing it,
 		 * otherwise read it if the backing disk is insync
 		 */
@@ -4081,7 +4149,7 @@ static void activate_bit_delay(struct r5conf *conf,
 	}
 }
 
-int md_raid5_congested(struct mddev *mddev, int bits)
+static int raid5_congested(struct mddev *mddev, int bits)
 {
 	struct r5conf *conf = mddev->private;
 
@@ -4098,24 +4166,14 @@ int md_raid5_congested(struct mddev *mddev, int bits)
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(md_raid5_congested);
-
-static int raid5_congested(void *data, int bits)
-{
-	struct mddev *mddev = data;
-
-	return mddev_congested(mddev, bits) ||
-		md_raid5_congested(mddev, bits);
-}
 
 /* We want read requests to align with chunks where possible,
  * but write requests don't need to.
  */
-static int raid5_mergeable_bvec(struct request_queue *q,
+static int raid5_mergeable_bvec(struct mddev *mddev,
 				struct bvec_merge_data *bvm,
 				struct bio_vec *biovec)
 {
-	struct mddev *mddev = q->queuedata;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 	int max;
 	unsigned int chunk_sectors = mddev->chunk_sectors;
@@ -5296,11 +5354,14 @@ static void raid5d(struct md_thread *thread)
 static ssize_t
 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
+	int ret = 0;
+	spin_lock(&mddev->lock);
+	conf = mddev->private;
 	if (conf)
-		return sprintf(page, "%d\n", conf->max_nr_stripes);
-	else
-		return 0;
+		ret = sprintf(page, "%d\n", conf->max_nr_stripes);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 int
@@ -5339,21 +5400,25 @@ EXPORT_SYMBOL(raid5_set_cache_size);
 static ssize_t
 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
 	unsigned long new;
 	int err;
 
 	if (len >= PAGE_SIZE)
 		return -EINVAL;
-	if (!conf)
-		return -ENODEV;
-
 	if (kstrtoul(page, 10, &new))
 		return -EINVAL;
-	err = raid5_set_cache_size(mddev, new);
+	err = mddev_lock(mddev);
 	if (err)
 		return err;
-	return len;
+	conf = mddev->private;
+	if (!conf)
+		err = -ENODEV;
+	else
+		err = raid5_set_cache_size(mddev, new);
+	mddev_unlock(mddev);
+
+	return err ?: len;
 }
 
 static struct md_sysfs_entry
@@ -5364,29 +5429,40 @@ raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
 static ssize_t
 raid5_show_preread_threshold(struct mddev *mddev, char *page)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
+	int ret = 0;
+	spin_lock(&mddev->lock);
+	conf = mddev->private;
 	if (conf)
-		return sprintf(page, "%d\n", conf->bypass_threshold);
-	else
-		return 0;
+		ret = sprintf(page, "%d\n", conf->bypass_threshold);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 static ssize_t
 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
 	unsigned long new;
+	int err;
+
 	if (len >= PAGE_SIZE)
 		return -EINVAL;
-	if (!conf)
-		return -ENODEV;
-
 	if (kstrtoul(page, 10, &new))
 		return -EINVAL;
-	if (new > conf->max_nr_stripes)
-		return -EINVAL;
-	conf->bypass_threshold = new;
-	return len;
+
+	err = mddev_lock(mddev);
+	if (err)
+		return err;
+	conf = mddev->private;
+	if (!conf)
+		err = -ENODEV;
+	else if (new > conf->max_nr_stripes)
+		err = -EINVAL;
+	else
+		conf->bypass_threshold = new;
+	mddev_unlock(mddev);
+	return err ?: len;
 }
 
 static struct md_sysfs_entry
@@ -5398,39 +5474,48 @@ raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
 static ssize_t
 raid5_show_skip_copy(struct mddev *mddev, char *page)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
+	int ret = 0;
+	spin_lock(&mddev->lock);
+	conf = mddev->private;
 	if (conf)
-		return sprintf(page, "%d\n", conf->skip_copy);
-	else
-		return 0;
+		ret = sprintf(page, "%d\n", conf->skip_copy);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 static ssize_t
 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
 	unsigned long new;
+	int err;
+
 	if (len >= PAGE_SIZE)
 		return -EINVAL;
-	if (!conf)
-		return -ENODEV;
-
 	if (kstrtoul(page, 10, &new))
 		return -EINVAL;
 	new = !!new;
-	if (new == conf->skip_copy)
-		return len;
 
-	mddev_suspend(mddev);
-	conf->skip_copy = new;
-	if (new)
-		mddev->queue->backing_dev_info.capabilities |=
-						BDI_CAP_STABLE_WRITES;
-	else
-		mddev->queue->backing_dev_info.capabilities &=
-						~BDI_CAP_STABLE_WRITES;
-	mddev_resume(mddev);
-	return len;
+	err = mddev_lock(mddev);
+	if (err)
+		return err;
+	conf = mddev->private;
+	if (!conf)
+		err = -ENODEV;
+	else if (new != conf->skip_copy) {
+		mddev_suspend(mddev);
+		conf->skip_copy = new;
+		if (new)
+			mddev->queue->backing_dev_info.capabilities |=
+				BDI_CAP_STABLE_WRITES;
+		else
+			mddev->queue->backing_dev_info.capabilities &=
+				~BDI_CAP_STABLE_WRITES;
+		mddev_resume(mddev);
+	}
+	mddev_unlock(mddev);
+	return err ?: len;
 }
 
 static struct md_sysfs_entry
@@ -5454,11 +5539,14 @@ raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
 static ssize_t
 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
+	int ret = 0;
+	spin_lock(&mddev->lock);
+	conf = mddev->private;
 	if (conf)
-		return sprintf(page, "%d\n", conf->worker_cnt_per_group);
-	else
-		return 0;
+		ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 static int alloc_thread_groups(struct r5conf *conf, int cnt,
@@ -5468,7 +5556,7 @@ static int alloc_thread_groups(struct r5conf *conf, int cnt,
 static ssize_t
 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf;
 	unsigned long new;
 	int err;
 	struct r5worker_group *new_groups, *old_groups;
@@ -5476,41 +5564,41 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
 
 	if (len >= PAGE_SIZE)
 		return -EINVAL;
-	if (!conf)
-		return -ENODEV;
-
 	if (kstrtoul(page, 10, &new))
 		return -EINVAL;
 
-	if (new == conf->worker_cnt_per_group)
-		return len;
-
-	mddev_suspend(mddev);
+	err = mddev_lock(mddev);
+	if (err)
+		return err;
+	conf = mddev->private;
+	if (!conf)
+		err = -ENODEV;
+	else if (new != conf->worker_cnt_per_group) {
+		mddev_suspend(mddev);
 
-	old_groups = conf->worker_groups;
-	if (old_groups)
-		flush_workqueue(raid5_wq);
+		old_groups = conf->worker_groups;
+		if (old_groups)
+			flush_workqueue(raid5_wq);
 
-	err = alloc_thread_groups(conf, new,
-				  &group_cnt, &worker_cnt_per_group,
-				  &new_groups);
-	if (!err) {
-		spin_lock_irq(&conf->device_lock);
-		conf->group_cnt = group_cnt;
-		conf->worker_cnt_per_group = worker_cnt_per_group;
-		conf->worker_groups = new_groups;
-		spin_unlock_irq(&conf->device_lock);
+		err = alloc_thread_groups(conf, new,
+					  &group_cnt, &worker_cnt_per_group,
+					  &new_groups);
+		if (!err) {
+			spin_lock_irq(&conf->device_lock);
+			conf->group_cnt = group_cnt;
+			conf->worker_cnt_per_group = worker_cnt_per_group;
+			conf->worker_groups = new_groups;
+			spin_unlock_irq(&conf->device_lock);
 
-		if (old_groups)
-			kfree(old_groups[0].workers);
-		kfree(old_groups);
+			if (old_groups)
+				kfree(old_groups[0].workers);
+			kfree(old_groups);
+		}
+		mddev_resume(mddev);
 	}
+	mddev_unlock(mddev);
 
-	mddev_resume(mddev);
-
-	if (err)
-		return err;
-	return len;
+	return err ?: len;
 }
 
 static struct md_sysfs_entry
@@ -6178,11 +6266,6 @@ static int run(struct mddev *mddev)
 		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
 			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
 
-		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
-
-		mddev->queue->backing_dev_info.congested_data = mddev;
-		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
-
 		chunk_size = mddev->chunk_sectors << 9;
 		blk_queue_io_min(mddev->queue, chunk_size);
 		blk_queue_io_opt(mddev->queue, chunk_size *
@@ -6260,17 +6343,12 @@ static int run(struct mddev *mddev)
 	return -EIO;
 }
 
-static int stop(struct mddev *mddev)
+static void raid5_free(struct mddev *mddev, void *priv)
 {
-	struct r5conf *conf = mddev->private;
+	struct r5conf *conf = priv;
 
-	md_unregister_thread(&mddev->thread);
-	if (mddev->queue)
-		mddev->queue->backing_dev_info.congested_fn = NULL;
 	free_conf(conf);
-	mddev->private = NULL;
 	mddev->to_remove = &raid5_attrs_group;
-	return 0;
 }
 
 static void status(struct seq_file *seq, struct mddev *mddev)
@@ -7044,7 +7122,7 @@ static struct md_personality raid6_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= raid5_free,
 	.status		= status,
 	.error_handler	= error,
 	.hot_add_disk	= raid5_add_disk,
@@ -7058,6 +7136,8 @@ static struct md_personality raid6_personality =
 	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid6_takeover,
+	.congested	= raid5_congested,
+	.mergeable_bvec	= raid5_mergeable_bvec,
 };
 static struct md_personality raid5_personality =
 {
@@ -7066,7 +7146,7 @@ static struct md_personality raid5_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= raid5_free,
 	.status		= status,
 	.error_handler	= error,
 	.hot_add_disk	= raid5_add_disk,
@@ -7080,6 +7160,8 @@ static struct md_personality raid5_personality =
 	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid5_takeover,
+	.congested	= raid5_congested,
+	.mergeable_bvec	= raid5_mergeable_bvec,
 };
 
 static struct md_personality raid4_personality =
@@ -7089,7 +7171,7 @@ static struct md_personality raid4_personality =
 	.owner		= THIS_MODULE,
 	.make_request	= make_request,
 	.run		= run,
-	.stop		= stop,
+	.free		= raid5_free,
 	.status		= status,
 	.error_handler	= error,
 	.hot_add_disk	= raid5_add_disk,
@@ -7103,6 +7185,8 @@ static struct md_personality raid4_personality =
 	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid4_takeover,
+	.congested	= raid5_congested,
+	.mergeable_bvec	= raid5_mergeable_bvec,
 };
 
 static int __init raid5_init(void)

drivers/md/raid5.h

@@ -558,7 +558,6 @@ static inline int algorithm_is_DDF(int layout)
 	return layout >= 8 && layout <= 10;
 }
 
-extern int md_raid5_congested(struct mddev *mddev, int bits);
 extern void md_raid5_kick_device(struct r5conf *conf);
 extern int raid5_set_cache_size(struct mddev *mddev, int size);
 #endif

lib/raid6/algos.c

@@ -89,10 +89,10 @@ void (*raid6_datap_recov)(int, size_t, int, void **);
 EXPORT_SYMBOL_GPL(raid6_datap_recov);
 
 const struct raid6_recov_calls *const raid6_recov_algos[] = {
-#if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
 #ifdef CONFIG_AS_AVX2
 	&raid6_recov_avx2,
 #endif
+#ifdef CONFIG_AS_SSSE3
 	&raid6_recov_ssse3,
 #endif
 	&raid6_recov_intx1,

lib/raid6/recov_avx2.c

@@ -8,7 +8,7 @@
  * of the License.
  */
 
-#if CONFIG_AS_AVX2
+#ifdef CONFIG_AS_AVX2
 
 #include <linux/raid/pq.h>
 #include "x86.h"

lib/raid6/recov_ssse3.c

@@ -7,6 +7,8 @@
  * of the License.
  */
 
+#ifdef CONFIG_AS_SSSE3
+
 #include <linux/raid/pq.h>
 #include "x86.h"
 
@@ -330,3 +332,7 @@ const struct raid6_recov_calls raid6_recov_ssse3 = {
 #endif
 	.priority = 1,
 };
+
+#else
+#warning "your version of binutils lacks SSSE3 support"
+#endif