add error handling to add_disk / device_add_disk

add error handling to add_disk / device_add_disk

[Christoph Hellwig]

Hi Jens,

this series does some refactoring and then adds support to return errors
from add_disk (rebasing a patch from Luis).  I think that alone is a huge
improvement as it leaves a disk for which add_disk failed in a defined
status, but the real improvement will be actually handling the errors in
the drivers.  This series contains two trivial conversions.  Luis has
a tree with conversions for all drivers in the tree, which will be fed
incrementally once this goes in.  Hopefully we can convert all the
commonly used drivers in this merge window.

This series sits on top of:

   "ensure each gendisk always has a request_queue reference v2"

A git tree is available here:

    git://git.infradead.org/users/hch/block.git

Gitweb:

    http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/add-disk-error-handling

Diffstat:
 block/blk-integrity.c         |   12 +-
 block/blk-sysfs.c             |    9 --
 block/blk.h                   |    7 -
 block/disk-events.c           |    7 -
 block/genhd.c                 |  186 ++++++++++++++++++++++--------------------
 drivers/block/null_blk/main.c |    3 
 drivers/block/virtio_blk.c    |    7 +
 include/linux/genhd.h         |    8 -
 8 files changed, 125 insertions(+), 114 deletions(-)

[PATCH 01/11] block: add a sanity check for a live disk in del_gendisk

[Christoph Hellwig]

Add a sanity check to del_gendisk to do nothing when the disk wasn't
successfully added.  This papers over the complete lack of add_disk
error handling, which is about to get fixed gradually.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 02cd9ec93e52..935f74c652f1 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -579,7 +579,7 @@ void del_gendisk(struct gendisk *disk)
 {
 	might_sleep();
 
-	if (WARN_ON_ONCE(!disk->queue))
+	if (WARN_ON_ONCE(!disk_live(disk)))
 		return;
 
 	blk_integrity_del(disk);
-- 
2.30.2

[PATCH 02/11] block: fold register_disk into device_add_disk

[Christoph Hellwig]

There is no real reason these should be separate.  Also simplify the
groups assignment a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 131 +++++++++++++++++++++++---------------------------
 1 file changed, 60 insertions(+), 71 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 935f74c652f1..ec4be5889fbf 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -409,71 +409,6 @@ static void disk_scan_partitions(struct gendisk *disk)
 		blkdev_put(bdev, FMODE_READ);
 }
 
-static void register_disk(struct device *parent, struct gendisk *disk,
-			  const struct attribute_group **groups)
-{
-	struct device *ddev = disk_to_dev(disk);
-	int err;
-
-	ddev->parent = parent;
-
-	dev_set_name(ddev, "%s", disk->disk_name);
-
-	/* delay uevents, until we scanned partition table */
-	dev_set_uevent_suppress(ddev, 1);
-
-	if (groups) {
-		WARN_ON(ddev->groups);
-		ddev->groups = groups;
-	}
-	if (device_add(ddev))
-		return;
-	if (!sysfs_deprecated) {
-		err = sysfs_create_link(block_depr, &ddev->kobj,
-					kobject_name(&ddev->kobj));
-		if (err) {
-			device_del(ddev);
-			return;
-		}
-	}
-
-	/*
-	 * avoid probable deadlock caused by allocating memory with
-	 * GFP_KERNEL in runtime_resume callback of its all ancestor
-	 * devices
-	 */
-	pm_runtime_set_memalloc_noio(ddev, true);
-
-	disk->part0->bd_holder_dir =
-		kobject_create_and_add("holders", &ddev->kobj);
-	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
-
-	/*
-	 * XXX: this is a mess, can't wait for real error handling in add_disk.
-	 * Make sure ->slave_dir is NULL if we failed some of the registration
-	 * so that the cleanup in bd_unlink_disk_holder works properly.
-	 */
-	if (bd_register_pending_holders(disk) < 0) {
-		kobject_put(disk->slave_dir);
-		disk->slave_dir = NULL;
-	}
-
-	if (disk->flags & GENHD_FL_HIDDEN)
-		return;
-
-	disk_scan_partitions(disk);
-
-	/* announce the disk and partitions after all partitions are created */
-	dev_set_uevent_suppress(ddev, 0);
-	disk_uevent(disk, KOBJ_ADD);
-
-	if (disk->bdi->dev) {
-		err = sysfs_create_link(&ddev->kobj, &disk->bdi->dev->kobj,
-					"bdi");
-		WARN_ON(err);
-	}
-}
-
 /**
  * device_add_disk - add disk information to kernel list
  * @parent: parent device for the disk
@@ -490,6 +425,7 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		     const struct attribute_group **groups)
 
 {
+	struct device *ddev = disk_to_dev(disk);
 	int ret;
 
 	/*
@@ -538,17 +474,70 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 		disk->flags |= GENHD_FL_NO_PART_SCAN;
 	} else {
-		struct device *dev = disk_to_dev(disk);
-
 		/* Register BDI before referencing it from bdev */
-		dev->devt = MKDEV(disk->major, disk->first_minor);
+		ddev->devt = MKDEV(disk->major, disk->first_minor);
 		ret = bdi_register(disk->bdi, "%u:%u",
 				   disk->major, disk->first_minor);
 		WARN_ON(ret);
-		bdi_set_owner(disk->bdi, dev);
-		bdev_add(disk->part0, dev->devt);
+		bdi_set_owner(disk->bdi, ddev);
+		bdev_add(disk->part0, ddev->devt);
+	}
+
+	/* delay uevents, until we scanned partition table */
+	dev_set_uevent_suppress(ddev, 1);
+
+	ddev->parent = parent;
+	ddev->groups = groups;
+	dev_set_name(ddev, "%s", disk->disk_name);
+	if (device_add(ddev))
+		return;
+	if (!sysfs_deprecated) {
+		ret = sysfs_create_link(block_depr, &ddev->kobj,
+					kobject_name(&ddev->kobj));
+		if (ret) {
+			device_del(ddev);
+			return;
+		}
 	}
-	register_disk(parent, disk, groups);
+
+	/*
+	 * avoid probable deadlock caused by allocating memory with
+	 * GFP_KERNEL in runtime_resume callback of its all ancestor
+	 * devices
+	 */
+	pm_runtime_set_memalloc_noio(ddev, true);
+
+	disk->part0->bd_holder_dir =
+		kobject_create_and_add("holders", &ddev->kobj);
+	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
+
+	/*
+	 * XXX: this is a mess, can't wait for real error handling in add_disk.
+	 * Make sure ->slave_dir is NULL if we failed some of the registration
+	 * so that the cleanup in bd_unlink_disk_holder works properly.
+	 */
+	if (bd_register_pending_holders(disk) < 0) {
+		kobject_put(disk->slave_dir);
+		disk->slave_dir = NULL;
+	}
+
+	if (!(disk->flags & GENHD_FL_HIDDEN)) {
+		disk_scan_partitions(disk);
+
+		/*
+		 * Announce the disk and partitions after all partitions are
+		 * created.
+		 */
+		dev_set_uevent_suppress(ddev, 0);
+		disk_uevent(disk, KOBJ_ADD);
+
+		if (disk->bdi->dev) {
+			ret = sysfs_create_link(&ddev->kobj,
+						&disk->bdi->dev->kobj, "bdi");
+			WARN_ON(ret);
+		}
+	}
+
 	blk_register_queue(disk);
 
 	disk_add_events(disk);
-- 
2.30.2

[PATCH 03/11] block: call bdev_add later in device_add_disk

[Christoph Hellwig]

Once bdev_add is called userspace can open the block device.  Ensure
that the struct device, which is used for refcounting of the disk
besides various other things, is fully setup at that point.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index ec4be5889fbf..ab455f110be2 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -466,29 +466,14 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk_alloc_events(disk);
 
-	if (disk->flags & GENHD_FL_HIDDEN) {
-		/*
-		 * Don't let hidden disks show up in /proc/partitions,
-		 * and don't bother scanning for partitions either.
-		 */
-		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
-		disk->flags |= GENHD_FL_NO_PART_SCAN;
-	} else {
-		/* Register BDI before referencing it from bdev */
-		ddev->devt = MKDEV(disk->major, disk->first_minor);
-		ret = bdi_register(disk->bdi, "%u:%u",
-				   disk->major, disk->first_minor);
-		WARN_ON(ret);
-		bdi_set_owner(disk->bdi, ddev);
-		bdev_add(disk->part0, ddev->devt);
-	}
-
 	/* delay uevents, until we scanned partition table */
 	dev_set_uevent_suppress(ddev, 1);
 
 	ddev->parent = parent;
 	ddev->groups = groups;
 	dev_set_name(ddev, "%s", disk->disk_name);
+	if (!(disk->flags & GENHD_FL_HIDDEN))
+		ddev->devt = MKDEV(disk->major, disk->first_minor);
 	if (device_add(ddev))
 		return;
 	if (!sysfs_deprecated) {
@@ -521,12 +506,25 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		disk->slave_dir = NULL;
 	}
 
-	if (!(disk->flags & GENHD_FL_HIDDEN)) {
+	if (disk->flags & GENHD_FL_HIDDEN) {
+		/*
+		 * Don't let hidden disks show up in /proc/partitions,
+		 * and don't bother scanning for partitions either.
+		 */
+		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
+		disk->flags |= GENHD_FL_NO_PART_SCAN;
+	} else {
+		ret = bdi_register(disk->bdi, "%u:%u",
+				   disk->major, disk->first_minor);
+		WARN_ON(ret);
+		bdi_set_owner(disk->bdi, ddev);
+		bdev_add(disk->part0, ddev->devt);
+
 		disk_scan_partitions(disk);
 
 		/*
 		 * Announce the disk and partitions after all partitions are
-		 * created.
+		 * created. (for hidden disks uevents remain suppressed forever)
 		 */
 		dev_set_uevent_suppress(ddev, 0);
 		disk_uevent(disk, KOBJ_ADD);
-- 
2.30.2

[PATCH 04/11] block: create the bdi link earlier in device_add_disk

[Christoph Hellwig]

This will simplify error handling going forward.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index ab455f110be2..f05e58f214d2 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -518,8 +518,13 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 				   disk->major, disk->first_minor);
 		WARN_ON(ret);
 		bdi_set_owner(disk->bdi, ddev);
-		bdev_add(disk->part0, ddev->devt);
+		if (disk->bdi->dev) {
+			ret = sysfs_create_link(&ddev->kobj,
+						&disk->bdi->dev->kobj, "bdi");
+			WARN_ON(ret);
+		}
 
+		bdev_add(disk->part0, ddev->devt);
 		disk_scan_partitions(disk);
 
 		/*
@@ -528,12 +533,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		 */
 		dev_set_uevent_suppress(ddev, 0);
 		disk_uevent(disk, KOBJ_ADD);
-
-		if (disk->bdi->dev) {
-			ret = sysfs_create_link(&ddev->kobj,
-						&disk->bdi->dev->kobj, "bdi");
-			WARN_ON(ret);
-		}
 	}
 
 	blk_register_queue(disk);
-- 
2.30.2

[PATCH 05/11] block: call blk_integrity_add earlier in device_add_disk

[Christoph Hellwig]

Doing all the sysfs file creation before adding the bdev and thus
allowing it to be opened will simplify the about to be added error
handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index f05e58f214d2..75d900e4c82f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -492,6 +492,8 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	 */
 	pm_runtime_set_memalloc_noio(ddev, true);
 
+	blk_integrity_add(disk);
+
 	disk->part0->bd_holder_dir =
 		kobject_create_and_add("holders", &ddev->kobj);
 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
@@ -538,7 +540,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	blk_register_queue(disk);
 
 	disk_add_events(disk);
-	blk_integrity_add(disk);
 }
 EXPORT_SYMBOL(device_add_disk);
 
-- 
2.30.2

[PATCH 06/11] block: call blk_register_queue earlier in device_add_disk

[Christoph Hellwig]

Ensure that all the sysfs bits are set up before bdev_add is called,
as that will make the upcomding error handling much easier.  However
this means the call to disk_update_readahead has to be split as that
requires a bdi.  Also remove various sanity checks that don't make
sense now that blk_register_queue only has a single caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-sysfs.c | 9 ---------
 block/genhd.c     | 5 +++--
 2 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 7fd99487300c..614d9d47de36 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -856,15 +856,6 @@ int blk_register_queue(struct gendisk *disk)
 	struct device *dev = disk_to_dev(disk);
 	struct request_queue *q = disk->queue;
 
-	if (WARN_ON(!q))
-		return -ENXIO;
-
-	WARN_ONCE(blk_queue_registered(q),
-		  "%s is registering an already registered queue\n",
-		  kobject_name(&dev->kobj));
-
-	disk_update_readahead(disk);
-
 	ret = blk_trace_init_sysfs(dev);
 	if (ret)
 		return ret;
diff --git a/block/genhd.c b/block/genhd.c
index 75d900e4c82f..a54b4849242c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -508,6 +508,8 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		disk->slave_dir = NULL;
 	}
 
+	blk_register_queue(disk);
+
 	if (disk->flags & GENHD_FL_HIDDEN) {
 		/*
 		 * Don't let hidden disks show up in /proc/partitions,
@@ -537,8 +539,7 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		disk_uevent(disk, KOBJ_ADD);
 	}
 
-	blk_register_queue(disk);
-
+	disk_update_readahead(disk);
 	disk_add_events(disk);
 }
 EXPORT_SYMBOL(device_add_disk);
-- 
2.30.2

[PATCH 07/11] block: return errors from blk_integrity_add

[Christoph Hellwig]

From: Luis Chamberlain <mcgrof@kernel.org>

Prepare for proper error handling in add_disk.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-integrity.c | 12 +++++++-----
 block/blk.h           |  5 +++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 410da060d1f5..69a12177dfb6 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -431,13 +431,15 @@ void blk_integrity_unregister(struct gendisk *disk)
 }
 EXPORT_SYMBOL(blk_integrity_unregister);
 
-void blk_integrity_add(struct gendisk *disk)
+int blk_integrity_add(struct gendisk *disk)
 {
-	if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
-				 &disk_to_dev(disk)->kobj, "%s", "integrity"))
-		return;
+	int ret;
 
-	kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
+	ret = kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
+				   &disk_to_dev(disk)->kobj, "%s", "integrity");
+	if (!ret)
+		kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
+	return ret;
 }
 
 void blk_integrity_del(struct gendisk *disk)
diff --git a/block/blk.h b/block/blk.h
index 148bdcd3aa08..c9727dd56da7 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -132,7 +132,7 @@ static inline bool integrity_req_gap_front_merge(struct request *req,
 				bip_next->bip_vec[0].bv_offset);
 }
 
-void blk_integrity_add(struct gendisk *);
+int blk_integrity_add(struct gendisk *disk);
 void blk_integrity_del(struct gendisk *);
 #else /* CONFIG_BLK_DEV_INTEGRITY */
 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
@@ -166,8 +166,9 @@ static inline bool bio_integrity_endio(struct bio *bio)
 static inline void bio_integrity_free(struct bio *bio)
 {
 }
-static inline void blk_integrity_add(struct gendisk *disk)
+static inline int blk_integrity_add(struct gendisk *disk)
 {
+	return 0;
 }
 static inline void blk_integrity_del(struct gendisk *disk)
 {
-- 
2.30.2

[PATCH 08/11] block: return errors from disk_alloc_events

[Christoph Hellwig]

From: Luis Chamberlain <mcgrof@kernel.org>

Prepare for proper error handling in add_disk.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h         | 2 +-
 block/disk-events.c | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index c9727dd56da7..bbbcc1a64a2d 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -362,7 +362,7 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 
 struct request_queue *blk_alloc_queue(int node_id);
 
-void disk_alloc_events(struct gendisk *disk);
+int disk_alloc_events(struct gendisk *disk);
 void disk_add_events(struct gendisk *disk);
 void disk_del_events(struct gendisk *disk);
 void disk_release_events(struct gendisk *disk);
diff --git a/block/disk-events.c b/block/disk-events.c
index 7445b8ff2775..8d5496e7592a 100644
--- a/block/disk-events.c
+++ b/block/disk-events.c
@@ -444,17 +444,17 @@ module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
 /*
  * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
  */
-void disk_alloc_events(struct gendisk *disk)
+int disk_alloc_events(struct gendisk *disk)
 {
 	struct disk_events *ev;
 
 	if (!disk->fops->check_events || !disk->events)
-		return;
+		return 0;
 
 	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
 	if (!ev) {
 		pr_warn("%s: failed to initialize events\n", disk->disk_name);
-		return;
+		return -ENOMEM;
 	}
 
 	INIT_LIST_HEAD(&ev->node);
@@ -466,6 +466,7 @@ void disk_alloc_events(struct gendisk *disk)
 	INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
 
 	disk->ev = ev;
+	return 0;
 }
 
 void disk_add_events(struct gendisk *disk)
-- 
2.30.2

[PATCH 09/11] block: add error handling for device_add_disk / add_disk

[Christoph Hellwig]

From: Luis Chamberlain <mcgrof@kernel.org>

Properly unwind on errors in device_add_disk.  This is the initial work
as drivers are not converted yet, which will follow in separate patches.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: major rebase.  All bugs are probably mine]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c         | 92 +++++++++++++++++++++++++++----------------
 include/linux/genhd.h |  8 ++--
 2 files changed, 62 insertions(+), 38 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index a54b4849242c..a925f773145f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -417,11 +417,8 @@ static void disk_scan_partitions(struct gendisk *disk)
  *
  * This function registers the partitioning information in @disk
  * with the kernel.
- *
- * FIXME: error handling
  */
-
-void device_add_disk(struct device *parent, struct gendisk *disk,
+int device_add_disk(struct device *parent, struct gendisk *disk,
 		     const struct attribute_group **groups)
 
 {
@@ -444,7 +441,8 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	 * and all partitions from the extended dev_t space.
 	 */
 	if (disk->major) {
-		WARN_ON(!disk->minors);
+		if (WARN_ON(!disk->minors))
+			return -EINVAL;
 
 		if (disk->minors > DISK_MAX_PARTS) {
 			pr_err("block: can't allocate more than %d partitions\n",
@@ -452,19 +450,20 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 			disk->minors = DISK_MAX_PARTS;
 		}
 	} else {
-		WARN_ON(disk->minors);
+		if (WARN_ON(disk->minors))
+			return -EINVAL;
 
 		ret = blk_alloc_ext_minor();
-		if (ret < 0) {
-			WARN_ON(1);
-			return;
-		}
+		if (ret < 0)
+			return ret;
 		disk->major = BLOCK_EXT_MAJOR;
 		disk->first_minor = MINOR(ret);
 		disk->flags |= GENHD_FL_EXT_DEVT;
 	}
 
-	disk_alloc_events(disk);
+	ret = disk_alloc_events(disk);
+	if (ret)
+		goto out_free_ext_minor;
 
 	/* delay uevents, until we scanned partition table */
 	dev_set_uevent_suppress(ddev, 1);
@@ -474,15 +473,14 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	dev_set_name(ddev, "%s", disk->disk_name);
 	if (!(disk->flags & GENHD_FL_HIDDEN))
 		ddev->devt = MKDEV(disk->major, disk->first_minor);
-	if (device_add(ddev))
-		return;
+	ret = device_add(ddev);
+	if (ret)
+		goto out_disk_release_events;
 	if (!sysfs_deprecated) {
 		ret = sysfs_create_link(block_depr, &ddev->kobj,
 					kobject_name(&ddev->kobj));
-		if (ret) {
-			device_del(ddev);
-			return;
-		}
+		if (ret)
+			goto out_device_del;
 	}
 
 	/*
@@ -492,23 +490,25 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	 */
 	pm_runtime_set_memalloc_noio(ddev, true);
 
-	blk_integrity_add(disk);
+	ret = blk_integrity_add(disk);
+	if (ret)
+		goto out_del_block_link;
 
 	disk->part0->bd_holder_dir =
 		kobject_create_and_add("holders", &ddev->kobj);
+	if (!disk->part0->bd_holder_dir)
+		goto out_del_integrity;
 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
+	if (!disk->slave_dir)
+		goto out_put_holder_dir;
 
-	/*
-	 * XXX: this is a mess, can't wait for real error handling in add_disk.
-	 * Make sure ->slave_dir is NULL if we failed some of the registration
-	 * so that the cleanup in bd_unlink_disk_holder works properly.
-	 */
-	if (bd_register_pending_holders(disk) < 0) {
-		kobject_put(disk->slave_dir);
-		disk->slave_dir = NULL;
-	}
+	ret = bd_register_pending_holders(disk);
+	if (ret < 0)
+		goto out_put_slave_dir;
 
-	blk_register_queue(disk);
+	ret = blk_register_queue(disk);
+	if (ret)
+		goto out_put_slave_dir;
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
 		/*
@@ -520,13 +520,13 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 	} else {
 		ret = bdi_register(disk->bdi, "%u:%u",
 				   disk->major, disk->first_minor);
-		WARN_ON(ret);
+		if (ret)
+			goto out_unregister_queue;
 		bdi_set_owner(disk->bdi, ddev);
-		if (disk->bdi->dev) {
-			ret = sysfs_create_link(&ddev->kobj,
-						&disk->bdi->dev->kobj, "bdi");
-			WARN_ON(ret);
-		}
+		ret = sysfs_create_link(&ddev->kobj,
+					&disk->bdi->dev->kobj, "bdi");
+		if (ret)
+			goto out_unregister_bdi;
 
 		bdev_add(disk->part0, ddev->devt);
 		disk_scan_partitions(disk);
@@ -541,6 +541,30 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk_update_readahead(disk);
 	disk_add_events(disk);
+	return 0;
+
+out_unregister_bdi:
+	if (!(disk->flags & GENHD_FL_HIDDEN))
+		bdi_unregister(disk->bdi);
+out_unregister_queue:
+	blk_unregister_queue(disk);
+out_put_slave_dir:
+	kobject_put(disk->slave_dir);
+out_put_holder_dir:
+	kobject_put(disk->part0->bd_holder_dir);
+out_del_integrity:
+	blk_integrity_del(disk);
+out_del_block_link:
+	if (!sysfs_deprecated)
+		sysfs_remove_link(block_depr, dev_name(ddev));
+out_device_del:
+	device_del(ddev);
+out_disk_release_events:
+	disk_release_events(disk);
+out_free_ext_minor:
+	if (disk->major == BLOCK_EXT_MAJOR)
+		blk_free_ext_minor(disk->first_minor);
+	return WARN_ON_ONCE(ret); /* keep until all callers handle errors */
 }
 EXPORT_SYMBOL(device_add_disk);
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 55acefdd8a20..c68d83c87f83 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -214,11 +214,11 @@ static inline dev_t disk_devt(struct gendisk *disk)
 void disk_uevent(struct gendisk *disk, enum kobject_action action);
 
 /* block/genhd.c */
-extern void device_add_disk(struct device *parent, struct gendisk *disk,
-			    const struct attribute_group **groups);
-static inline void add_disk(struct gendisk *disk)
+int device_add_disk(struct device *parent, struct gendisk *disk,
+		const struct attribute_group **groups);
+static inline int add_disk(struct gendisk *disk)
 {
-	device_add_disk(NULL, disk, NULL);
+	return device_add_disk(NULL, disk, NULL);
 }
 extern void del_gendisk(struct gendisk *gp);
 
-- 
2.30.2

[PATCH 10/11] virtio_blk: add error handling support for add_disk()

[Christoph Hellwig]

From: Luis Chamberlain <mcgrof@kernel.org>

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/block/virtio_blk.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 767b4f72a54d..63dc121a4c43 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -875,9 +875,14 @@ static int virtblk_probe(struct virtio_device *vdev)
 	virtblk_update_capacity(vblk, false);
 	virtio_device_ready(vdev);
 
-	device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
+	err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
+	if (err)
+		goto out_cleanup_disk;
+
 	return 0;
 
+out_cleanup_disk:
+	blk_cleanup_disk(vblk->disk);
 out_free_tags:
 	blk_mq_free_tag_set(&vblk->tag_set);
 out_free_vq:
-- 
2.30.2

[PATCH 11/11] null_blk: add error handling support for add_disk()

[Christoph Hellwig]

From: Luis Chamberlain <mcgrof@kernel.org>

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling. The actual cleanup in case of error is
already handled by the caller of null_gendisk_register().

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/null_blk/main.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index f128242d1170..187d779c8ca0 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1717,8 +1717,7 @@ static int null_gendisk_register(struct nullb *nullb)
 			return ret;
 	}
 
-	add_disk(disk);
-	return 0;
+	return add_disk(disk);
 }
 
 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
-- 
2.30.2

Re: [PATCH 01/11] block: add a sanity check for a live disk in del_gendisk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> Add a sanity check to del_gendisk to do nothing when the disk wasn't
> successfully added.  This papers over the complete lack of add_disk
> error handling, which is about to get fixed gradually.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 02cd9ec93e52..935f74c652f1 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -579,7 +579,7 @@ void del_gendisk(struct gendisk *disk)
>   {
>   	might_sleep();
>   
> -	if (WARN_ON_ONCE(!disk->queue))
> +	if (WARN_ON_ONCE(!disk_live(disk)))
>   		return;
>   
>   	blk_integrity_del(disk);
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 02/11] block: fold register_disk into device_add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> There is no real reason these should be separate.  Also simplify the
> groups assignment a bit.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 131 +++++++++++++++++++++++---------------------------
>   1 file changed, 60 insertions(+), 71 deletions(-)
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 03/11] block: call bdev_add later in device_add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> Once bdev_add is called userspace can open the block device.  Ensure
> that the struct device, which is used for refcounting of the disk
> besides various other things, is fully setup at that point.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 36 +++++++++++++++++-------------------
>   1 file changed, 17 insertions(+), 19 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 04/11] block: create the bdi link earlier in device_add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> This will simplify error handling going forward.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 05/11] block: call blk_integrity_add earlier in device_add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> Doing all the sysfs file creation before adding the bdev and thus
> allowing it to be opened will simplify the about to be added error
> handling.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 06/11] block: call blk_register_queue earlier in device_add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> Ensure that all the sysfs bits are set up before bdev_add is called,
> as that will make the upcomding error handling much easier.  However
> this means the call to disk_update_readahead has to be split as that
> requires a bdi.  Also remove various sanity checks that don't make
> sense now that blk_register_queue only has a single caller.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-sysfs.c | 9 ---------
>   block/genhd.c     | 5 +++--
>   2 files changed, 3 insertions(+), 11 deletions(-)
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 07/11] block: return errors from blk_integrity_add

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> Prepare for proper error handling in add_disk.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> [hch: split from a larger patch]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-integrity.c | 12 +++++++-----
>   block/blk.h           |  5 +++--
>   2 files changed, 10 insertions(+), 7 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 08/11] block: return errors from disk_alloc_events

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> Prepare for proper error handling in add_disk.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> [hch: split from a larger patch]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk.h         | 2 +-
>   block/disk-events.c | 7 ++++---
>   2 files changed, 5 insertions(+), 4 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 09/11] block: add error handling for device_add_disk / add_disk

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> Properly unwind on errors in device_add_disk.  This is the initial work
> as drivers are not converted yet, which will follow in separate patches.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> [hch: major rebase.  All bugs are probably mine]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c         | 92 +++++++++++++++++++++++++++----------------
>   include/linux/genhd.h |  8 ++--
>   2 files changed, 62 insertions(+), 38 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 10/11] virtio_blk: add error handling support for add_disk()

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> We never checked for errors on add_disk() as this function
> returned void. Now that this is fixed, use the shiny new
> error handling.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>   drivers/block/virtio_blk.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH 11/11] null_blk: add error handling support for add_disk()

[Hannes Reinecke]

On 8/18/21 4:45 PM, Christoph Hellwig wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> We never checked for errors on add_disk() as this function
> returned void. Now that this is fixed, use the shiny new
> error handling. The actual cleanup in case of error is
> already handled by the caller of null_gendisk_register().
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/block/null_blk/main.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: add error handling to add_disk / device_add_disk

[Jens Axboe]

On 8/18/21 8:45 AM, Christoph Hellwig wrote:
> Hi Jens,
> 
> this series does some refactoring and then adds support to return errors
> from add_disk (rebasing a patch from Luis).  I think that alone is a huge
> improvement as it leaves a disk for which add_disk failed in a defined
> status, but the real improvement will be actually handling the errors in
> the drivers.  This series contains two trivial conversions.  Luis has
> a tree with conversions for all drivers in the tree, which will be fed
> incrementally once this goes in.  Hopefully we can convert all the
> commonly used drivers in this merge window.

Applied, thanks.

-- 
Jens Axboe

Re: add error handling to add_disk / device_add_disk

[Luis Chamberlain]

On Mon, Aug 23, 2021 at 12:57:41PM -0600, Jens Axboe wrote:
> On 8/18/21 8:45 AM, Christoph Hellwig wrote:
> > Hi Jens,
> > 
> > this series does some refactoring and then adds support to return errors
> > from add_disk (rebasing a patch from Luis).  I think that alone is a huge
> > improvement as it leaves a disk for which add_disk failed in a defined
> > status, but the real improvement will be actually handling the errors in
> > the drivers.  This series contains two trivial conversions.  Luis has
> > a tree with conversions for all drivers in the tree, which will be fed
> > incrementally once this goes in.  Hopefully we can convert all the
> > commonly used drivers in this merge window.
> 
> Applied, thanks.

Do you have a branch published which has this by any chance? I checked
but can't see anything obvious.

  Luis

Re: add error handling to add_disk / device_add_disk

[Jens Axboe]

On 8/23/21 1:44 PM, Luis Chamberlain wrote:
> On Mon, Aug 23, 2021 at 12:57:41PM -0600, Jens Axboe wrote:
>> On 8/18/21 8:45 AM, Christoph Hellwig wrote:
>>> Hi Jens,
>>>
>>> this series does some refactoring and then adds support to return errors
>>> from add_disk (rebasing a patch from Luis).  I think that alone is a huge
>>> improvement as it leaves a disk for which add_disk failed in a defined
>>> status, but the real improvement will be actually handling the errors in
>>> the drivers.  This series contains two trivial conversions.  Luis has
>>> a tree with conversions for all drivers in the tree, which will be fed
>>> incrementally once this goes in.  Hopefully we can convert all the
>>> commonly used drivers in this merge window.
>>
>> Applied, thanks.
> 
> Do you have a branch published which has this by any chance? I checked
> but can't see anything obvious.

It's in the core branch, just hadn't been pushed out yet. Now it is,
find it in for-5.15/block

-- 
Jens Axboe