Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.2/block

Pull MD fixes from Song.

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid1: stop mdx_raid1 thread when raid1 array run failed
  md/raid5: use bdev_write_cache instead of open coding it
  md: fix a crash in mempool_free
  md/raid0, raid10: Don't set discard sectors for request queue
  md/bitmap: Fix bitmap chunk size overflow issues
  md: introduce md_ro_state
  md: factor out __md_set_array_info()
  lib/raid6: drop RAID6_USE_EMPTY_ZERO_PAGE
  raid5-cache: use try_cmpxchg in r5l_wake_reclaim
  drivers/md/md-bitmap: check the return value of md_bitmap_get_counter()

9 files changed, 156 insertions, 146 deletions

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index bf6dffadbe6f..e7cc6ba1b657 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -486,7 +486,7 @@ void md_bitmap_print_sb(struct bitmap *bitmap)
 	sb = kmap_atomic(bitmap->storage.sb_page);
 	pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 	pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
-	pr_debug("       version: %d\n", le32_to_cpu(sb->version));
+	pr_debug("       version: %u\n", le32_to_cpu(sb->version));
 	pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 		 le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 		 le32_to_cpu(*(__le32 *)(sb->uuid+4)),
@@ -497,11 +497,11 @@ void md_bitmap_print_sb(struct bitmap *bitmap)
 	pr_debug("events cleared: %llu\n",
 		 (unsigned long long) le64_to_cpu(sb->events_cleared));
 	pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
-	pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
-	pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
+	pr_debug("     chunksize: %u B\n", le32_to_cpu(sb->chunksize));
+	pr_debug("  daemon sleep: %us\n", le32_to_cpu(sb->daemon_sleep));
 	pr_debug("     sync size: %llu KB\n",
 		 (unsigned long long)le64_to_cpu(sb->sync_size)/2);
-	pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
+	pr_debug("max write behind: %u\n", le32_to_cpu(sb->write_behind));
 	kunmap_atomic(sb);
 }
 
@@ -2105,7 +2105,8 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 			bytes = DIV_ROUND_UP(chunks, 8);
 			if (!bitmap->mddev->bitmap_info.external)
 				bytes += sizeof(bitmap_super_t);
-		} while (bytes > (space << 9));
+		} while (bytes > (space << 9) && (chunkshift + BITMAP_BLOCK_SHIFT) <
+			(BITS_PER_BYTE * sizeof(((bitmap_super_t *)0)->chunksize) - 1));
 	} else
 		chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
 
@@ -2150,7 +2151,7 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 	bitmap->counts.missing_pages = pages;
 	bitmap->counts.chunkshift = chunkshift;
 	bitmap->counts.chunks = chunks;
-	bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
+	bitmap->mddev->bitmap_info.chunksize = 1UL << (chunkshift +
 						     BITMAP_BLOCK_SHIFT);
 
 	blocks = min(old_counts.chunks << old_counts.chunkshift,
@@ -2176,8 +2177,8 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 				bitmap->counts.missing_pages = old_counts.pages;
 				bitmap->counts.chunkshift = old_counts.chunkshift;
 				bitmap->counts.chunks = old_counts.chunks;
-				bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
-									     BITMAP_BLOCK_SHIFT);
+				bitmap->mddev->bitmap_info.chunksize =
+					1UL << (old_counts.chunkshift + BITMAP_BLOCK_SHIFT);
 				blocks = old_counts.chunks << old_counts.chunkshift;
 				pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
 				break;
@@ -2195,20 +2196,23 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 
 		if (set) {
 			bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
-			if (*bmc_new == 0) {
-				/* need to set on-disk bits too. */
-				sector_t end = block + new_blocks;
-				sector_t start = block >> chunkshift;
-				start <<= chunkshift;
-				while (start < end) {
-					md_bitmap_file_set_bit(bitmap, block);
-					start += 1 << chunkshift;
+			if (bmc_new) {
+				if (*bmc_new == 0) {
+					/* need to set on-disk bits too. */
+					sector_t end = block + new_blocks;
+					sector_t start = block >> chunkshift;
+
+					start <<= chunkshift;
+					while (start < end) {
+						md_bitmap_file_set_bit(bitmap, block);
+						start += 1 << chunkshift;
+					}
+					*bmc_new = 2;
+					md_bitmap_count_page(&bitmap->counts, block, 1);
+					md_bitmap_set_pending(&bitmap->counts, block);
 				}
-				*bmc_new = 2;
-				md_bitmap_count_page(&bitmap->counts, block, 1);
-				md_bitmap_set_pending(&bitmap->counts, block);
+				*bmc_new |= NEEDED_MASK;
 			}
-			*bmc_new |= NEEDED_MASK;
 			if (new_blocks < old_blocks)
 				old_blocks = new_blocks;
 		}
@@ -2534,6 +2538,9 @@ chunksize_store(struct mddev *mddev, const char *buf, size_t len)
 	if (csize < 512 ||
 	    !is_power_of_2(csize))
 		return -EINVAL;
+	if (BITS_PER_LONG > 32 && csize >= (1ULL << (BITS_PER_BYTE *
+		sizeof(((bitmap_super_t *)0)->chunksize))))
+		return -EOVERFLOW;
 	mddev->bitmap_info.chunksize = csize;
 	return len;
 }
diff --git a/drivers/md/md.c b/drivers/md/md.c
index a467b492d4ad..f95b86440485 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -93,6 +93,18 @@ static int remove_and_add_spares(struct mddev *mddev,
 				 struct md_rdev *this);
 static void mddev_detach(struct mddev *mddev);
 
+enum md_ro_state {
+	MD_RDWR,
+	MD_RDONLY,
+	MD_AUTO_READ,
+	MD_MAX_STATE
+};
+
+static bool md_is_rdwr(struct mddev *mddev)
+{
+	return (mddev->ro == MD_RDWR);
+}
+
 /*
  * Default number of read corrections we'll attempt on an rdev
  * before ejecting it from the array. We divide the read error
@@ -444,7 +456,7 @@ static void md_submit_bio(struct bio *bio)
 
 	bio = bio_split_to_limits(bio);
 
-	if (mddev->ro == 1 && unlikely(rw == WRITE)) {
+	if (mddev->ro == MD_RDONLY && unlikely(rw == WRITE)) {
 		if (bio_sectors(bio) != 0)
 			bio->bi_status = BLK_STS_IOERR;
 		bio_endio(bio);
@@ -509,13 +521,14 @@ static void md_end_flush(struct bio *bio)
 	struct md_rdev *rdev = bio->bi_private;
 	struct mddev *mddev = rdev->mddev;
 
+	bio_put(bio);
+
 	rdev_dec_pending(rdev, mddev);
 
 	if (atomic_dec_and_test(&mddev->flush_pending)) {
 		/* The pre-request flush has finished */
 		queue_work(md_wq, &mddev->flush_work);
 	}
-	bio_put(bio);
 }
 
 static void md_submit_flush_data(struct work_struct *ws);
@@ -913,10 +926,12 @@ static void super_written(struct bio *bio)
 	} else
 		clear_bit(LastDev, &rdev->flags);
 
+	bio_put(bio);
+
+	rdev_dec_pending(rdev, mddev);
+
 	if (atomic_dec_and_test(&mddev->pending_writes))
 		wake_up(&mddev->sb_wait);
-	rdev_dec_pending(rdev, mddev);
-	bio_put(bio);
 }
 
 void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
@@ -2639,7 +2654,7 @@ void md_update_sb(struct mddev *mddev, int force_change)
 	int any_badblocks_changed = 0;
 	int ret = -1;
 
-	if (mddev->ro) {
+	if (!md_is_rdwr(mddev)) {
 		if (force_change)
 			set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
 		return;
@@ -3901,7 +3916,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
 		goto out_unlock;
 	}
 	rv = -EROFS;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
 		goto out_unlock;
 
 	/* request to change the personality.  Need to ensure:
@@ -4107,7 +4122,7 @@ layout_store(struct mddev *mddev, const char *buf, size_t len)
 	if (mddev->pers) {
 		if (mddev->pers->check_reshape == NULL)
 			err = -EBUSY;
-		else if (mddev->ro)
+		else if (!md_is_rdwr(mddev))
 			err = -EROFS;
 		else {
 			mddev->new_layout = n;
@@ -4216,7 +4231,7 @@ chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
 	if (mddev->pers) {
 		if (mddev->pers->check_reshape == NULL)
 			err = -EBUSY;
-		else if (mddev->ro)
+		else if (!md_is_rdwr(mddev))
 			err = -EROFS;
 		else {
 			mddev->new_chunk_sectors = n >> 9;
@@ -4339,13 +4354,13 @@ array_state_show(struct mddev *mddev, char *page)
 
 	if (mddev->pers && !test_bit(MD_NOT_READY, &mddev->flags)) {
 		switch(mddev->ro) {
-		case 1:
+		case MD_RDONLY:
 			st = readonly;
 			break;
-		case 2:
+		case MD_AUTO_READ:
 			st = read_auto;
 			break;
-		case 0:
+		case MD_RDWR:
 			spin_lock(&mddev->lock);
 			if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
 				st = write_pending;
@@ -4381,7 +4396,8 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
 	int err = 0;
 	enum array_state st = match_word(buf, array_states);
 
-	if (mddev->pers && (st == active || st == clean) && mddev->ro != 1) {
+	if (mddev->pers && (st == active || st == clean) &&
+	    mddev->ro != MD_RDONLY) {
 		/* don't take reconfig_mutex when toggling between
 		 * clean and active
 		 */
@@ -4425,23 +4441,23 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
 		if (mddev->pers)
 			err = md_set_readonly(mddev, NULL);
 		else {
-			mddev->ro = 1;
+			mddev->ro = MD_RDONLY;
 			set_disk_ro(mddev->gendisk, 1);
 			err = do_md_run(mddev);
 		}
 		break;
 	case read_auto:
 		if (mddev->pers) {
-			if (mddev->ro == 0)
+			if (md_is_rdwr(mddev))
 				err = md_set_readonly(mddev, NULL);
-			else if (mddev->ro == 1)
+			else if (mddev->ro == MD_RDONLY)
 				err = restart_array(mddev);
 			if (err == 0) {
-				mddev->ro = 2;
+				mddev->ro = MD_AUTO_READ;
 				set_disk_ro(mddev->gendisk, 0);
 			}
 		} else {
-			mddev->ro = 2;
+			mddev->ro = MD_AUTO_READ;
 			err = do_md_run(mddev);
 		}
 		break;
@@ -4466,7 +4482,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
 			wake_up(&mddev->sb_wait);
 			err = 0;
 		} else {
-			mddev->ro = 0;
+			mddev->ro = MD_RDWR;
 			set_disk_ro(mddev->gendisk, 0);
 			err = do_md_run(mddev);
 		}
@@ -4765,7 +4781,7 @@ action_show(struct mddev *mddev, char *page)
 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
 		type = "frozen";
 	else if (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
-	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
+	    (md_is_rdwr(mddev) && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
 			type = "reshape";
 		else if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
@@ -4851,11 +4867,11 @@ action_store(struct mddev *mddev, const char *page, size_t len)
 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 	}
-	if (mddev->ro == 2) {
+	if (mddev->ro == MD_AUTO_READ) {
 		/* A write to sync_action is enough to justify
 		 * canceling read-auto mode
 		 */
-		mddev->ro = 0;
+		mddev->ro = MD_RDWR;
 		md_wakeup_thread(mddev->sync_thread);
 	}
 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -5083,8 +5099,7 @@ max_sync_store(struct mddev *mddev, const char *buf, size_t len)
 			goto out_unlock;
 
 		err = -EBUSY;
-		if (max < mddev->resync_max &&
-		    mddev->ro == 0 &&
+		if (max < mddev->resync_max && md_is_rdwr(mddev) &&
 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
 			goto out_unlock;
 
@@ -5813,8 +5828,8 @@ int md_run(struct mddev *mddev)
 			continue;
 		sync_blockdev(rdev->bdev);
 		invalidate_bdev(rdev->bdev);
-		if (mddev->ro != 1 && rdev_read_only(rdev)) {
-			mddev->ro = 1;
+		if (mddev->ro != MD_RDONLY && rdev_read_only(rdev)) {
+			mddev->ro = MD_RDONLY;
 			if (mddev->gendisk)
 				set_disk_ro(mddev->gendisk, 1);
 		}
@@ -5917,8 +5932,8 @@ int md_run(struct mddev *mddev)
 
 	mddev->ok_start_degraded = start_dirty_degraded;
 
-	if (start_readonly && mddev->ro == 0)
-		mddev->ro = 2; /* read-only, but switch on first write */
+	if (start_readonly && md_is_rdwr(mddev))
+		mddev->ro = MD_AUTO_READ; /* read-only, but switch on first write */
 
 	err = pers->run(mddev);
 	if (err)
@@ -5996,8 +6011,8 @@ int md_run(struct mddev *mddev)
 		mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
 		mddev->sysfs_completed = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_completed");
 		mddev->sysfs_degraded = sysfs_get_dirent_safe(mddev->kobj.sd, "degraded");
-	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
-		mddev->ro = 0;
+	} else if (mddev->ro == MD_AUTO_READ)
+		mddev->ro = MD_RDWR;
 
 	atomic_set(&mddev->max_corr_read_errors,
 		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
@@ -6015,7 +6030,7 @@ int md_run(struct mddev *mddev)
 		if (rdev->raid_disk >= 0)
 			sysfs_link_rdev(mddev, rdev); /* failure here is OK */
 
-	if (mddev->degraded && !mddev->ro)
+	if (mddev->degraded && md_is_rdwr(mddev))
 		/* This ensures that recovering status is reported immediately
 		 * via sysfs - until a lack of spares is confirmed.
 		 */
@@ -6105,7 +6120,7 @@ static int restart_array(struct mddev *mddev)
 		return -ENXIO;
 	if (!mddev->pers)
 		return -EINVAL;
-	if (!mddev->ro)
+	if (md_is_rdwr(mddev))
 		return -EBUSY;
 
 	rcu_read_lock();
@@ -6124,7 +6139,7 @@ static int restart_array(struct mddev *mddev)
 		return -EROFS;
 
 	mddev->safemode = 0;
-	mddev->ro = 0;
+	mddev->ro = MD_RDWR;
 	set_disk_ro(disk, 0);
 	pr_debug("md: %s switched to read-write mode.\n", mdname(mddev));
 	/* Kick recovery or resync if necessary */
@@ -6151,7 +6166,7 @@ static void md_clean(struct mddev *mddev)
 	mddev->clevel[0] = 0;
 	mddev->flags = 0;
 	mddev->sb_flags = 0;
-	mddev->ro = 0;
+	mddev->ro = MD_RDWR;
 	mddev->metadata_type[0] = 0;
 	mddev->chunk_sectors = 0;
 	mddev->ctime = mddev->utime = 0;
@@ -6203,7 +6218,7 @@ static void __md_stop_writes(struct mddev *mddev)
 	}
 	md_bitmap_flush(mddev);
 
-	if (mddev->ro == 0 &&
+	if (md_is_rdwr(mddev) &&
 	    ((!mddev->in_sync && !mddev_is_clustered(mddev)) ||
 	     mddev->sb_flags)) {
 		/* mark array as shutdown cleanly */
@@ -6312,9 +6327,9 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 		__md_stop_writes(mddev);
 
 		err  = -ENXIO;
-		if (mddev->ro==1)
+		if (mddev->ro == MD_RDONLY)
 			goto out;
-		mddev->ro = 1;
+		mddev->ro = MD_RDONLY;
 		set_disk_ro(mddev->gendisk, 1);
 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -6371,7 +6386,7 @@ static int do_md_stop(struct mddev *mddev, int mode,
 		return -EBUSY;
 	}
 	if (mddev->pers) {
-		if (mddev->ro)
+		if (!md_is_rdwr(mddev))
 			set_disk_ro(disk, 0);
 
 		__md_stop_writes(mddev);
@@ -6388,8 +6403,8 @@ static int do_md_stop(struct mddev *mddev, int mode,
 		mutex_unlock(&mddev->open_mutex);
 		mddev->changed = 1;
 
-		if (mddev->ro)
-			mddev->ro = 0;
+		if (!md_is_rdwr(mddev))
+			mddev->ro = MD_RDWR;
 	} else
 		mutex_unlock(&mddev->open_mutex);
 	/*
@@ -7204,7 +7219,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
 	    mddev->sync_thread)
 		return -EBUSY;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
 		return -EROFS;
 
 	rdev_for_each(rdev, mddev) {
@@ -7234,7 +7249,7 @@ static int update_raid_disks(struct mddev *mddev, int raid_disks)
 	/* change the number of raid disks */
 	if (mddev->pers->check_reshape == NULL)
 		return -EINVAL;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
 		return -EROFS;
 	if (raid_disks <= 0 ||
 	    (mddev->max_disks && raid_disks >= mddev->max_disks))
@@ -7464,6 +7479,40 @@ static inline bool md_ioctl_valid(unsigned int cmd)
 	}
 }
 
+static int __md_set_array_info(struct mddev *mddev, void __user *argp)
+{
+	mdu_array_info_t info;
+	int err;
+
+	if (!argp)
+		memset(&info, 0, sizeof(info));
+	else if (copy_from_user(&info, argp, sizeof(info)))
+		return -EFAULT;
+
+	if (mddev->pers) {
+		err = update_array_info(mddev, &info);
+		if (err)
+			pr_warn("md: couldn't update array info. %d\n", err);
+		return err;
+	}
+
+	if (!list_empty(&mddev->disks)) {
+		pr_warn("md: array %s already has disks!\n", mdname(mddev));
+		return -EBUSY;
+	}
+
+	if (mddev->raid_disks) {
+		pr_warn("md: array %s already initialised!\n", mdname(mddev));
+		return -EBUSY;
+	}
+
+	err = md_set_array_info(mddev, &info);
+	if (err)
+		pr_warn("md: couldn't set array info. %d\n", err);
+
+	return err;
+}
+
 static int md_ioctl(struct block_device *bdev, fmode_t mode,
 			unsigned int cmd, unsigned long arg)
 {
@@ -7569,36 +7618,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 	}
 
 	if (cmd == SET_ARRAY_INFO) {
-		mdu_array_info_t info;
-		if (!arg)
-			memset(&info, 0, sizeof(info));
-		else if (copy_from_user(&info, argp, sizeof(info))) {
-			err = -EFAULT;
-			goto unlock;
-		}
-		if (mddev->pers) {
-			err = update_array_info(mddev, &info);
-			if (err) {
-				pr_warn("md: couldn't update array info. %d\n", err);
-				goto unlock;
-			}
-			goto unlock;
-		}
-		if (!list_empty(&mddev->disks)) {
-			pr_warn("md: array %s already has disks!\n", mdname(mddev));
-			err = -EBUSY;
-			goto unlock;
-		}
-		if (mddev->raid_disks) {
-			pr_warn("md: array %s already initialised!\n", mdname(mddev));
-			err = -EBUSY;
-			goto unlock;
-		}
-		err = md_set_array_info(mddev, &info);
-		if (err) {
-			pr_warn("md: couldn't set array info. %d\n", err);
-			goto unlock;
-		}
+		err = __md_set_array_info(mddev, argp);
 		goto unlock;
 	}
 
@@ -7658,26 +7678,25 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 	 * The remaining ioctls are changing the state of the
 	 * superblock, so we do not allow them on read-only arrays.
 	 */
-	if (mddev->ro && mddev->pers) {
-		if (mddev->ro == 2) {
-			mddev->ro = 0;
-			sysfs_notify_dirent_safe(mddev->sysfs_state);
-			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-			/* mddev_unlock will wake thread */
-			/* If a device failed while we were read-only, we
-			 * need to make sure the metadata is updated now.
-			 */
-			if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
-				mddev_unlock(mddev);
-				wait_event(mddev->sb_wait,
-					   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
-					   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
-				mddev_lock_nointr(mddev);
-			}
-		} else {
+	if (!md_is_rdwr(mddev) && mddev->pers) {
+		if (mddev->ro != MD_AUTO_READ) {
 			err = -EROFS;
 			goto unlock;
 		}
+		mddev->ro = MD_RDWR;
+		sysfs_notify_dirent_safe(mddev->sysfs_state);
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		/* mddev_unlock will wake thread */
+		/* If a device failed while we were read-only, we
+		 * need to make sure the metadata is updated now.
+		 */
+		if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
+			mddev_unlock(mddev);
+			wait_event(mddev->sb_wait,
+				   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
+				   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
+			mddev_lock_nointr(mddev);
+		}
 	}
 
 	switch (cmd) {
@@ -7763,11 +7782,11 @@ static int md_set_read_only(struct block_device *bdev, bool ro)
 	 * Transitioning to read-auto need only happen for arrays that call
 	 * md_write_start and which are not ready for writes yet.
 	 */
-	if (!ro && mddev->ro == 1 && mddev->pers) {
+	if (!ro && mddev->ro == MD_RDONLY && mddev->pers) {
 		err = restart_array(mddev);
 		if (err)
 			goto out_unlock;
-		mddev->ro = 2;
+		mddev->ro = MD_AUTO_READ;
 	}
 
 out_unlock:
@@ -8241,9 +8260,9 @@ static int md_seq_show(struct seq_file *seq, void *v)
 		seq_printf(seq, "%s : %sactive", mdname(mddev),
 						mddev->pers ? "" : "in");
 		if (mddev->pers) {
-			if (mddev->ro==1)
+			if (mddev->ro == MD_RDONLY)
 				seq_printf(seq, " (read-only)");
-			if (mddev->ro==2)
+			if (mddev->ro == MD_AUTO_READ)
 				seq_printf(seq, " (auto-read-only)");
 			seq_printf(seq, " %s", mddev->pers->name);
 		}
@@ -8502,10 +8521,10 @@ bool md_write_start(struct mddev *mddev, struct bio *bi)
 	if (bio_data_dir(bi) != WRITE)
 		return true;
 
-	BUG_ON(mddev->ro == 1);
-	if (mddev->ro == 2) {
+	BUG_ON(mddev->ro == MD_RDONLY);
+	if (mddev->ro == MD_AUTO_READ) {
 		/* need to switch to read/write */
-		mddev->ro = 0;
+		mddev->ro = MD_RDWR;
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		md_wakeup_thread(mddev->thread);
 		md_wakeup_thread(mddev->sync_thread);
@@ -8556,7 +8575,7 @@ void md_write_inc(struct mddev *mddev, struct bio *bi)
 {
 	if (bio_data_dir(bi) != WRITE)
 		return;
-	WARN_ON_ONCE(mddev->in_sync || mddev->ro);
+	WARN_ON_ONCE(mddev->in_sync || !md_is_rdwr(mddev));
 	percpu_ref_get(&mddev->writes_pending);
 }
 EXPORT_SYMBOL(md_write_inc);
@@ -8661,7 +8680,7 @@ void md_allow_write(struct mddev *mddev)
 {
 	if (!mddev->pers)
 		return;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
 		return;
 	if (!mddev->pers->sync_request)
 		return;
@@ -8709,7 +8728,7 @@ void md_do_sync(struct md_thread *thread)
 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
 	    test_bit(MD_RECOVERY_WAIT, &mddev->recovery))
 		return;
-	if (mddev->ro) {/* never try to sync a read-only array */
+	if (!md_is_rdwr(mddev)) {/* never try to sync a read-only array */
 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 		return;
 	}
@@ -9178,9 +9197,9 @@ static int remove_and_add_spares(struct mddev *mddev,
 		if (test_bit(Faulty, &rdev->flags))
 			continue;
 		if (!test_bit(Journal, &rdev->flags)) {
-			if (mddev->ro &&
-			    ! (rdev->saved_raid_disk >= 0 &&
-			       !test_bit(Bitmap_sync, &rdev->flags)))
+			if (!md_is_rdwr(mddev) &&
+			    !(rdev->saved_raid_disk >= 0 &&
+			      !test_bit(Bitmap_sync, &rdev->flags)))
 				continue;
 
 			rdev->recovery_offset = 0;
@@ -9278,7 +9297,8 @@ void md_check_recovery(struct mddev *mddev)
 		flush_signals(current);
 	}
 
-	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+	if (!md_is_rdwr(mddev) &&
+	    !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
 		return;
 	if ( ! (
 		(mddev->sb_flags & ~ (1<<MD_SB_CHANGE_PENDING)) ||
@@ -9297,7 +9317,7 @@ void md_check_recovery(struct mddev *mddev)
 		if (!mddev->external && mddev->safemode == 1)
 			mddev->safemode = 0;
 
-		if (mddev->ro) {
+		if (!md_is_rdwr(mddev)) {
 			struct md_rdev *rdev;
 			if (!mddev->external && mddev->in_sync)
 				/* 'Blocked' flag not needed as failed devices
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 857c49399c28..b536befd8898 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -398,7 +398,6 @@ static int raid0_run(struct mddev *mddev)
 
 		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
 		blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
-		blk_queue_max_discard_sectors(mddev->queue, UINT_MAX);
 
 		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
 		blk_queue_io_opt(mddev->queue,
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 05d8438cfec8..58f705f42948 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -3159,6 +3159,7 @@ static int raid1_run(struct mddev *mddev)
 	 * RAID1 needs at least one disk in active
 	 */
 	if (conf->raid_disks - mddev->degraded < 1) {
+		md_unregister_thread(&conf->thread);
 		ret = -EINVAL;
 		goto abort;
 	}
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 3aa8b6e11d58..9a6503f5cb98 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4145,8 +4145,6 @@ static int raid10_run(struct mddev *mddev)
 	conf->thread = NULL;
 
 	if (mddev->queue) {
-		blk_queue_max_discard_sectors(mddev->queue,
-					      UINT_MAX);
 		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
 		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
 		raid10_set_io_opt(conf);
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 832d8566e165..46182b955aef 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1565,11 +1565,12 @@ void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
 
 	if (!log)
 		return;
+
+	target = READ_ONCE(log->reclaim_target);
 	do {
-		target = log->reclaim_target;
 		if (new < target)
 			return;
-	} while (cmpxchg(&log->reclaim_target, target, new) != target);
+	} while (!try_cmpxchg(&log->reclaim_target, &target, new));
 	md_wakeup_thread(log->reclaim_thread);
 }
 
@@ -3061,7 +3062,6 @@ void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
 
 int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 {
-	struct request_queue *q = bdev_get_queue(rdev->bdev);
 	struct r5l_log *log;
 	int ret;
 
@@ -3090,9 +3090,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 	if (!log)
 		return -ENOMEM;
 	log->rdev = rdev;
-
-	log->need_cache_flush = test_bit(QUEUE_FLAG_WC, &q->queue_flags) != 0;
-
+	log->need_cache_flush = bdev_write_cache(rdev->bdev);
 	log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
 				       sizeof(rdev->mddev->uuid));
 
diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
index 31b9157bc9ae..e495939bb3e0 100644
--- a/drivers/md/raid5-ppl.c
+++ b/drivers/md/raid5-ppl.c
@@ -1301,8 +1301,6 @@ static int ppl_validate_rdev(struct md_rdev *rdev)
 
 static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
 {
-	struct request_queue *q;
-
 	if ((rdev->ppl.size << 9) >= (PPL_SPACE_SIZE +
 				      PPL_HEADER_SIZE) * 2) {
 		log->use_multippl = true;
@@ -1316,8 +1314,7 @@ static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
 	}
 	log->next_io_sector = rdev->ppl.sector;
 
-	q = bdev_get_queue(rdev->bdev);
-	if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
+	if (bdev_write_cache(rdev->bdev))
 		log->wb_cache_on = true;
 }
 
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index d6e5a1feb947..f29aaaf2eb21 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -10,17 +10,9 @@
 
 #ifdef __KERNEL__
 
-/* Set to 1 to use kernel-wide empty_zero_page */
-#define RAID6_USE_EMPTY_ZERO_PAGE 0
 #include <linux/blkdev.h>
 
-/* We need a pre-zeroed page... if we don't want to use the kernel-provided
-   one define it here */
-#if RAID6_USE_EMPTY_ZERO_PAGE
-# define raid6_empty_zero_page empty_zero_page
-#else
 extern const char raid6_empty_zero_page[PAGE_SIZE];
-#endif
 
 #else /* ! __KERNEL__ */
 /* Used for testing in user space */
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 39b74221f4a7..a22a05c9af8a 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -18,12 +18,10 @@
 #else
 #include <linux/module.h>
 #include <linux/gfp.h>
-#if !RAID6_USE_EMPTY_ZERO_PAGE
 /* In .bss so it's zeroed */
 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
 EXPORT_SYMBOL(raid6_empty_zero_page);
 #endif
-#endif
 
 struct raid6_calls raid6_call;
 EXPORT_SYMBOL_GPL(raid6_call);