Merge tag 'md-next-20230927' of...

Merge tag 'md-next-20230927' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.7/block

Pull MD updates from Song:

"1. Make rdev add/remove independent from daemon thread, by Yu Kuai;
 2. Refactor code around quiesce() and mddev_suspend(), by Yu Kuai."

* tag 'md-next-20230927' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: replace deprecated strncpy with memcpy
  md/md-linear: Annotate struct linear_conf with __counted_by
  md: don't check 'mddev->pers' and 'pers->quiesce' from suspend_lo_store()
  md: don't check 'mddev->pers' from suspend_hi_store()
  md-bitmap: suspend array earlier in location_store()
  md-bitmap: remove the checking of 'pers->quiesce' from location_store()
  md: don't rely on 'mddev->pers' to be set in mddev_suspend()
  md: initialize 'writes_pending' while allocating mddev
  md: initialize 'active_io' while allocating mddev
  md: delay remove_and_add_spares() for read only array to md_start_sync()
  md: factor out a helper rdev_addable() from remove_and_add_spares()
  md: factor out a helper rdev_is_spare() from remove_and_add_spares()
  md: factor out a helper rdev_removeable() from remove_and_add_spares()
  md: delay choosing sync action to md_start_sync()
  md: factor out a helper to choose sync action from md_check_recovery()
  md: use separate work_struct for md_start_sync()

drivers/md/dm-raid.c

@@ -749,7 +749,11 @@ static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *r
 		return ERR_PTR(-ENOMEM);
 	}
 
-	mddev_init(&rs->md);
+	if (mddev_init(&rs->md)) {
+		kfree(rs);
+		ti->error = "Cannot initialize raid context";
+		return ERR_PTR(-ENOMEM);
+	}
 
 	rs->raid_disks = raid_devs;
 	rs->delta_disks = 0;
@@ -798,6 +802,7 @@ static void raid_set_free(struct raid_set *rs)
 			dm_put_device(rs->ti, rs->dev[i].data_dev);
 	}
 
+	mddev_destroy(&rs->md);
 	kfree(rs);
 }
 

drivers/md/md-bitmap.c

@@ -2351,11 +2351,9 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
 	rv = mddev_lock(mddev);
 	if (rv)
 		return rv;
+
+	mddev_suspend(mddev);
 	if (mddev->pers) {
-		if (!mddev->pers->quiesce) {
-			rv = -EBUSY;
-			goto out;
-		}
 		if (mddev->recovery || mddev->sync_thread) {
 			rv = -EBUSY;
 			goto out;
@@ -2369,11 +2367,8 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
 			rv = -EBUSY;
 			goto out;
 		}
-		if (mddev->pers) {
-			mddev_suspend(mddev);
-			md_bitmap_destroy(mddev);
-			mddev_resume(mddev);
-		}
+
+		md_bitmap_destroy(mddev);
 		mddev->bitmap_info.offset = 0;
 		if (mddev->bitmap_info.file) {
 			struct file *f = mddev->bitmap_info.file;
@@ -2383,6 +2378,8 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
 	} else {
 		/* No bitmap, OK to set a location */
 		long long offset;
+		struct bitmap *bitmap;
+
 		if (strncmp(buf, "none", 4) == 0)
 			/* nothing to be done */;
 		else if (strncmp(buf, "file:", 5) == 0) {
@@ -2406,25 +2403,20 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
 				rv = -EINVAL;
 				goto out;
 			}
+
 			mddev->bitmap_info.offset = offset;
-			if (mddev->pers) {
-				struct bitmap *bitmap;
-				bitmap = md_bitmap_create(mddev, -1);
-				mddev_suspend(mddev);
-				if (IS_ERR(bitmap))
-					rv = PTR_ERR(bitmap);
-				else {
-					mddev->bitmap = bitmap;
-					rv = md_bitmap_load(mddev);
-					if (rv)
-						mddev->bitmap_info.offset = 0;
-				}
-				if (rv) {
-					md_bitmap_destroy(mddev);
-					mddev_resume(mddev);
-					goto out;
-				}
-				mddev_resume(mddev);
+			bitmap = md_bitmap_create(mddev, -1);
+			if (IS_ERR(bitmap)) {
+				rv = PTR_ERR(bitmap);
+				goto out;
+			}
+
+			mddev->bitmap = bitmap;
+			rv = md_bitmap_load(mddev);
+			if (rv) {
+				mddev->bitmap_info.offset = 0;
+				md_bitmap_destroy(mddev);
+				goto out;
 			}
 		}
 	}
@@ -2437,6 +2429,7 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
 	}
 	rv = 0;
 out:
+	mddev_resume(mddev);
 	mddev_unlock(mddev);
 	if (rv)
 		return rv;

drivers/md/md-linear.c

@@ -69,6 +69,19 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
 	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;
 
@@ -112,19 +125,6 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
 			conf->disks[i-1].end_sector +
 			conf->disks[i].rdev->sectors;
 
-	/*
-	 * conf->raid_disks is copy of mddev->raid_disks. The reason to
-	 * keep a copy of mddev->raid_disks in struct linear_conf is,
-	 * mddev->raid_disks may not be consistent with pointers number of
-	 * conf->disks[] when it is updated in linear_add() and used to
-	 * iterate old conf->disks[] earray in linear_congested().
-	 * Here conf->raid_disks is always consitent with number of
-	 * pointers in conf->disks[] array, and mddev->private is updated
-	 * with rcu_assign_pointer() in linear_addr(), such race can be
-	 * avoided.
-	 */
-	conf->raid_disks = raid_disks;
-
 	return conf;
 
 out:

drivers/md/md-linear.h

@@ -12,6 +12,6 @@ struct linear_conf
 	struct rcu_head		rcu;
 	sector_t		array_sectors;
 	int			raid_disks; /* a copy of mddev->raid_disks */
-	struct dev_info		disks[];
+	struct dev_info		disks[] __counted_by(raid_disks);
 };
 #endif

drivers/md/md.h

@@ -453,7 +453,10 @@ struct mddev {
 	struct kernfs_node		*sysfs_degraded;	/*handle for 'degraded' */
 	struct kernfs_node		*sysfs_level;		/*handle for 'level' */
 
-	struct work_struct del_work;	/* used for delayed sysfs removal */
+	/* used for delayed sysfs removal */
+	struct work_struct del_work;
+	/* used for register new sync thread */
+	struct work_struct sync_work;
 
 	/* "lock" protects:
 	 *   flush_bio transition from NULL to !NULL
@@ -768,7 +771,6 @@ extern void md_unregister_thread(struct mddev *mddev, struct md_thread __rcu **t
 extern void md_wakeup_thread(struct md_thread __rcu *thread);
 extern void md_check_recovery(struct mddev *mddev);
 extern void md_reap_sync_thread(struct mddev *mddev);
-extern int mddev_init_writes_pending(struct mddev *mddev);
 extern bool md_write_start(struct mddev *mddev, struct bio *bi);
 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
 extern void md_write_end(struct mddev *mddev);
@@ -795,7 +797,8 @@ extern int md_integrity_register(struct mddev *mddev);
 extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 
-extern void mddev_init(struct mddev *mddev);
+extern int mddev_init(struct mddev *mddev);
+extern void mddev_destroy(struct mddev *mddev);
 struct mddev *md_alloc(dev_t dev, char *name);
 void mddev_put(struct mddev *mddev);
 extern int md_run(struct mddev *mddev);

drivers/md/raid1.c

@@ -3122,8 +3122,7 @@ static int raid1_run(struct mddev *mddev)
 			mdname(mddev));
 		return -EIO;
 	}
-	if (mddev_init_writes_pending(mddev) < 0)
-		return -ENOMEM;
+
 	/*
 	 * copy the already verified devices into our private RAID1
 	 * bookkeeping area. [whatever we allocate in run(),

drivers/md/raid10.c

@@ -4154,9 +4154,6 @@ static int raid10_run(struct mddev *mddev)
 	sector_t min_offset_diff = 0;
 	int first = 1;
 
-	if (mddev_init_writes_pending(mddev) < 0)
-		return -ENOMEM;
-
 	if (mddev->private == NULL) {
 		conf = setup_conf(mddev);
 		if (IS_ERR(conf))

drivers/md/raid5.c

@@ -7778,9 +7778,6 @@ static int raid5_run(struct mddev *mddev)
 	long long min_offset_diff = 0;
 	int first = 1;
 
-	if (mddev_init_writes_pending(mddev) < 0)
-		return -ENOMEM;
-
 	if (mddev->recovery_cp != MaxSector)
 		pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
 			  mdname(mddev));