[PATCH 0/3] Introduce device_add_disk() to kill gendisk.driverfs_dev

[PATCH 0/3] Introduce device_add_disk() to kill gendisk.driverfs_dev

[Dan Williams]

Answer the "// FIXME: remove" include/linux/genhd.h.  This should be
functionally equivalent to the previous state.  Now that the WARN_ON()
for the registration failure case is up-levelled to some drivers, they
can take on the follow on work to handle device_add_disk() failures.

Note, a full run from the kbuild robot is still pending.  I'll post v2
if it reports anything against this set on top of current -next.

---

Dan Williams (3):
      block: introduce device_add_disk()
      block: convert to device_add_disk()
      block: remove ->driverfs_dev


 arch/powerpc/sysdev/axonram.c       |    3 +--
 arch/um/drivers/ubd_kern.c          |    3 +--
 block/genhd.c                       |   27 ++++++++++++---------------
 drivers/block/cciss.c               |    3 +--
 drivers/block/floppy.c              |    4 ++--
 drivers/block/mtip32xx/mtip32xx.c   |    5 ++---
 drivers/block/ps3disk.c             |    3 +--
 drivers/block/ps3vram.c             |    3 +--
 drivers/block/rsxx/dev.c            |    4 +---
 drivers/block/skd_main.c            |    8 +++-----
 drivers/block/sunvdc.c              |    3 +--
 drivers/block/virtio_blk.c          |    3 +--
 drivers/block/xen-blkfront.c        |    3 +--
 drivers/ide/ide-cd.c                |    3 +--
 drivers/ide/ide-gd.c                |    3 +--
 drivers/memstick/core/ms_block.c    |    3 +--
 drivers/memstick/core/mspro_block.c |    3 +--
 drivers/mmc/card/block.c            |    3 +--
 drivers/mtd/mtd_blkdevs.c           |    4 +---
 drivers/nvdimm/blk.c                |    3 +--
 drivers/nvdimm/btt.c                |    3 +--
 drivers/nvdimm/bus.c                |    2 +-
 drivers/nvdimm/pmem.c               |    3 +--
 drivers/nvme/host/core.c            |    3 +--
 drivers/s390/block/dasd_genhd.c     |    3 +--
 drivers/s390/block/dcssblk.c        |    3 +--
 drivers/s390/block/scm_blk.c        |    3 +--
 drivers/scsi/sd.c                   |    3 +--
 drivers/scsi/sr.c                   |    3 +--
 include/linux/genhd.h               |    8 ++++++--
 30 files changed, 50 insertions(+), 78 deletions(-)

[PATCH 1/3] block: introduce device_add_disk()

[Dan Williams]

In preparation for removing the ->driverfs_dev member of a gendisk, add
an api that takes the parent device as a parameter to add_disk().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 block/genhd.c         |   22 ++++++++++------------
 include/linux/genhd.h |    8 +++++++-
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index eb05dfc1dffe..3fa2654ada52 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -506,7 +506,7 @@ static int exact_lock(dev_t devt, void *data)
 	return 0;
 }
 
-static void register_disk(struct gendisk *disk)
+static void register_disk(struct device *parent, struct gendisk *disk)
 {
 	struct device *ddev = disk_to_dev(disk);
 	struct block_device *bdev;
@@ -514,7 +514,7 @@ static void register_disk(struct gendisk *disk)
 	struct hd_struct *part;
 	int err;
 
-	ddev->parent = disk->driverfs_dev;
+	ddev->parent = parent;
 
 	dev_set_name(ddev, "%s", disk->disk_name);
 
@@ -573,7 +573,8 @@ exit:
 }
 
 /**
- * add_disk - add partitioning information to kernel list
+ * device_add_disk - add partitioning information to kernel list
+ * @parent: parent device for the disk
  * @disk: per-device partitioning information
  *
  * This function registers the partitioning information in @disk
@@ -581,7 +582,7 @@ exit:
  *
  * FIXME: error handling
  */
-void add_disk(struct gendisk *disk)
+int device_add_disk(struct device *parent, struct gendisk *disk)
 {
 	struct backing_dev_info *bdi;
 	dev_t devt;
@@ -597,10 +598,8 @@ void add_disk(struct gendisk *disk)
 	disk->flags |= GENHD_FL_UP;
 
 	retval = blk_alloc_devt(&disk->part0, &devt);
-	if (retval) {
-		WARN_ON(1);
-		return;
-	}
+	if (retval)
+		return retval;
 	disk_to_dev(disk)->devt = devt;
 
 	/* ->major and ->first_minor aren't supposed to be
@@ -617,7 +616,7 @@ void add_disk(struct gendisk *disk)
 
 	blk_register_region(disk_devt(disk), disk->minors, NULL,
 			    exact_match, exact_lock, disk);
-	register_disk(disk);
+	register_disk(parent, disk);
 	blk_register_queue(disk);
 
 	/*
@@ -628,12 +627,11 @@ void add_disk(struct gendisk *disk)
 
 	retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
 				   "bdi");
-	WARN_ON(retval);
-
 	disk_add_events(disk);
 	blk_integrity_add(disk);
+	return retval;
 }
-EXPORT_SYMBOL(add_disk);
+EXPORT_SYMBOL(device_add_disk);
 
 void del_gendisk(struct gendisk *disk)
 {
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 5c706765404a..6fa03fe589ad 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -431,7 +431,13 @@ static inline void free_part_info(struct hd_struct *part)
 extern void part_round_stats(int cpu, struct hd_struct *part);
 
 /* block/genhd.c */
-extern void add_disk(struct gendisk *disk);
+extern int device_add_disk(struct device *parent, struct gendisk *disk);
+static inline void add_disk(struct gendisk *disk)
+{
+	/* temporary while we convert callers to device_add_disk */
+	WARN_ON(device_add_disk(disk->driverfs_dev, disk) != 0);
+}
+
 extern void del_gendisk(struct gendisk *gp);
 extern struct gendisk *get_gendisk(dev_t dev, int *partno);
 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);

[PATCH 2/3] block: convert to device_add_disk()

[Dan Williams]

For block drivers that specify a parent device, convert them to use
device_add_disk().  For now this is functionally equivalent to the
previous state in that errors are just reported with a WARN_ON().

This conversion was done with the following semantic patch:

    @@
    struct gendisk *disk;
    expression E;
    @@

    - disk->driverfs_dev = E;
    ...
    - add_disk(disk);
    + WARN_ON(device_add_disk(E, disk) != 0);

    @@
    struct gendisk *disk;
    expression E1, E2;
    @@

    - disk->driverfs_dev = E1;
    ...
    E2 = disk;
    ...
    - add_disk(E2);
    + WARN_ON(device_add_disk(E1, E2));

...plus some manual fixups for a few missed conversions.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: James E.J. Bottomley <JBottomley@odin.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/powerpc/sysdev/axonram.c       |    3 +--
 arch/um/drivers/ubd_kern.c          |    3 +--
 drivers/block/cciss.c               |    3 +--
 drivers/block/floppy.c              |    4 ++--
 drivers/block/mtip32xx/mtip32xx.c   |    5 ++---
 drivers/block/ps3disk.c             |    3 +--
 drivers/block/ps3vram.c             |    3 +--
 drivers/block/rsxx/dev.c            |    4 +---
 drivers/block/skd_main.c            |    8 +++-----
 drivers/block/sunvdc.c              |    3 +--
 drivers/block/virtio_blk.c          |    3 +--
 drivers/block/xen-blkfront.c        |    3 +--
 drivers/ide/ide-cd.c                |    3 +--
 drivers/ide/ide-gd.c                |    3 +--
 drivers/memstick/core/ms_block.c    |    3 +--
 drivers/memstick/core/mspro_block.c |    3 +--
 drivers/mmc/card/block.c            |    3 +--
 drivers/mtd/mtd_blkdevs.c           |    4 +---
 drivers/nvdimm/blk.c                |    3 +--
 drivers/nvdimm/btt.c                |    3 +--
 drivers/nvdimm/pmem.c               |    3 +--
 drivers/nvme/host/core.c            |    3 +--
 drivers/s390/block/dasd_genhd.c     |    3 +--
 drivers/s390/block/dcssblk.c        |    3 +--
 drivers/s390/block/scm_blk.c        |    3 +--
 drivers/scsi/sd.c                   |    3 +--
 drivers/scsi/sr.c                   |    3 +--
 27 files changed, 31 insertions(+), 60 deletions(-)

diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index 0d112b94d91d..01837c08b605 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -223,7 +223,6 @@ static int axon_ram_probe(struct platform_device *device)
 	bank->disk->first_minor = azfs_minor;
 	bank->disk->fops = &axon_ram_devops;
 	bank->disk->private_data = bank;
-	bank->disk->driverfs_dev = &device->dev;
 
 	sprintf(bank->disk->disk_name, "%s%d",
 			AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
@@ -238,7 +237,7 @@ static int axon_ram_probe(struct platform_device *device)
 	set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
 	blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
 	blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
-	add_disk(bank->disk);
+	WARN_ON(device_add_disk(&device->dev, bank->disk) != 0);
 
 	bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
 	if (bank->irq_id == NO_IRQ) {
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 39ba20755e03..6eed85f0508f 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -823,12 +823,11 @@ static int ubd_disk_register(int major, u64 size, int unit,
 		ubd_devs[unit].pdev.dev.release = ubd_device_release;
 		dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
 		platform_device_register(&ubd_devs[unit].pdev);
-		disk->driverfs_dev = &ubd_devs[unit].pdev.dev;
 	}
 
 	disk->private_data = &ubd_devs[unit];
 	disk->queue = ubd_devs[unit].queue;
-	add_disk(disk);
+	WARN_ON(device_add_disk(&ubd_devs[unit].pdev.dev, disk) != 0);
 
 	*disk_out = disk;
 	return 0;
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 63c2064689f8..7f7324fee7d6 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -1951,7 +1951,6 @@ static int cciss_add_disk(ctlr_info_t *h, struct gendisk *disk,
 	if (cciss_create_ld_sysfs_entry(h, drv_index))
 		goto cleanup_queue;
 	disk->private_data = h->drv[drv_index];
-	disk->driverfs_dev = &h->drv[drv_index]->dev;
 
 	/* Set up queue information */
 	blk_queue_bounce_limit(disk->queue, h->pdev->dma_mask);
@@ -1973,7 +1972,7 @@ static int cciss_add_disk(ctlr_info_t *h, struct gendisk *disk,
 	/* allows the interrupt handler to start the queue */
 	wmb();
 	h->drv[drv_index]->queue = disk->queue;
-	add_disk(disk);
+	WARN_ON(device_add_disk(&h->drv[drv_index]->dev, disk) != 0);
 	return 0;
 
 cleanup_queue:
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 84708a5f8c52..d0b397a80c5c 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4349,8 +4349,8 @@ static int __init do_floppy_init(void)
 		/* to be cleaned up... */
 		disks[drive]->private_data = (void *)(long)drive;
 		disks[drive]->flags |= GENHD_FL_REMOVABLE;
-		disks[drive]->driverfs_dev = &floppy_device[drive].dev;
-		add_disk(disks[drive]);
+		WARN_ON(device_add_disk(&floppy_device[drive].dev,
+					disks[drive]) != 0);
 	}
 
 	return 0;
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 9b180dbbd03c..098ed0cb8b9f 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3840,7 +3840,6 @@ static int mtip_block_initialize(struct driver_data *dd)
 	if (rv)
 		goto disk_index_error;
 
-	dd->disk->driverfs_dev	= &dd->pdev->dev;
 	dd->disk->major		= dd->major;
 	dd->disk->first_minor	= index * MTIP_MAX_MINORS;
 	dd->disk->minors 	= MTIP_MAX_MINORS;
@@ -3891,7 +3890,7 @@ skip_create_disk:
 
 	/*
 	 * if rebuild pending, start the service thread, and delay the block
-	 * queue creation and add_disk()
+	 * queue creation and device_add_disk()
 	 */
 	if (wait_for_rebuild == MTIP_FTL_REBUILD_MAGIC)
 		goto start_service_thread;
@@ -3931,7 +3930,7 @@ skip_create_disk:
 	set_capacity(dd->disk, capacity);
 
 	/* Enable the block device and add it to /dev */
-	add_disk(dd->disk);
+	WARN_ON(device_add_disk(&dd->pdev->dev, dd->disk) != 0);
 
 	dd->bdev = bdget_disk(dd->disk, 0);
 	/*
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index c120d70d3fb3..6d8181d79733 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -487,7 +487,6 @@ static int ps3disk_probe(struct ps3_system_bus_device *_dev)
 	gendisk->fops = &ps3disk_fops;
 	gendisk->queue = queue;
 	gendisk->private_data = dev;
-	gendisk->driverfs_dev = &dev->sbd.core;
 	snprintf(gendisk->disk_name, sizeof(gendisk->disk_name), PS3DISK_NAME,
 		 devidx+'a');
 	priv->blocking_factor = dev->blk_size >> 9;
@@ -499,7 +498,7 @@ static int ps3disk_probe(struct ps3_system_bus_device *_dev)
 		 gendisk->disk_name, priv->model, priv->raw_capacity >> 11,
 		 get_capacity(gendisk) >> 11);
 
-	add_disk(gendisk);
+	WARN_ON(device_add_disk(&dev->sbd.core, gendisk) != 0);
 	return 0;
 
 fail_cleanup_queue:
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index 56847fcda086..38da9070321b 100644
--- a/drivers/block/ps3vram.c
+++ b/drivers/block/ps3vram.c
@@ -773,14 +773,13 @@ static int ps3vram_probe(struct ps3_system_bus_device *dev)
 	gendisk->fops = &ps3vram_fops;
 	gendisk->queue = queue;
 	gendisk->private_data = dev;
-	gendisk->driverfs_dev = &dev->core;
 	strlcpy(gendisk->disk_name, DEVICE_NAME, sizeof(gendisk->disk_name));
 	set_capacity(gendisk, priv->size >> 9);
 
 	dev_info(&dev->core, "%s: Using %lu MiB of GPU memory\n",
 		 gendisk->disk_name, get_capacity(gendisk) >> 11);
 
-	add_disk(gendisk);
+	WARN_ON(device_add_disk(&dev->core, gendisk) != 0);
 	return 0;
 
 fail_cleanup_queue:
diff --git a/drivers/block/rsxx/dev.c b/drivers/block/rsxx/dev.c
index e1b8b7061d2f..de69939eb421 100644
--- a/drivers/block/rsxx/dev.c
+++ b/drivers/block/rsxx/dev.c
@@ -230,8 +230,7 @@ int rsxx_attach_dev(struct rsxx_cardinfo *card)
 			set_capacity(card->gendisk, card->size8 >> 9);
 		else
 			set_capacity(card->gendisk, 0);
-		add_disk(card->gendisk);
-
+		WARN_ON(device_add_disk(&card->dev->dev, card->gendisk) != 0);
 		card->bdev_attached = 1;
 	}
 
@@ -308,7 +307,6 @@ int rsxx_setup_dev(struct rsxx_cardinfo *card)
 
 	snprintf(card->gendisk->disk_name, sizeof(card->gendisk->disk_name),
 		 "rsxx%d", card->disk_id);
-	card->gendisk->driverfs_dev = &card->dev->dev;
 	card->gendisk->major = card->major;
 	card->gendisk->first_minor = 0;
 	card->gendisk->fops = &rsxx_fops;
diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index 586f9168ffa4..7e02311a2dde 100644
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -4747,10 +4747,10 @@ static int skd_bdev_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 	return -EIO;
 }
 
-static int skd_bdev_attach(struct skd_device *skdev)
+static int skd_bdev_attach(struct device *parent, struct skd_device *skdev)
 {
 	pr_debug("%s:%s:%d add_disk\n", skdev->name, __func__, __LINE__);
-	add_disk(skdev->disk);
+	WARN_ON(device_add_disk(parent, skdev->disk) != 0);
 	return 0;
 }
 
@@ -4869,8 +4869,6 @@ static int skd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	pci_set_drvdata(pdev, skdev);
 
-	skdev->disk->driverfs_dev = &pdev->dev;
-
 	for (i = 0; i < SKD_MAX_BARS; i++) {
 		skdev->mem_phys[i] = pci_resource_start(pdev, i);
 		skdev->mem_size[i] = (u32)pci_resource_len(pdev, i);
@@ -4908,7 +4906,7 @@ static int skd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 					      (SKD_START_WAIT_SECONDS * HZ));
 	if (skdev->gendisk_on > 0) {
 		/* device came on-line after reset */
-		skd_bdev_attach(skdev);
+		skd_bdev_attach(&pdev->dev, skdev);
 		rc = 0;
 	} else {
 		/* we timed out, something is wrong with the device,
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 4b911ed96ea3..2f8770d714cd 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -804,7 +804,6 @@ static int probe_disk(struct vdc_port *port)
 	g->fops = &vdc_fops;
 	g->queue = q;
 	g->private_data = port;
-	g->driverfs_dev = &port->vio.vdev->dev;
 
 	set_capacity(g, port->vdisk_size);
 
@@ -835,7 +834,7 @@ static int probe_disk(struct vdc_port *port)
 	       port->vdisk_size, (port->vdisk_size >> (20 - 9)),
 	       port->vio.ver.major, port->vio.ver.minor);
 
-	add_disk(g);
+	WARN_ON(device_add_disk(&port->vio.vdev->dev, g) != 0);
 
 	return 0;
 }
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 6ca35495a5be..c7d4e8675140 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -655,7 +655,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	vblk->disk->first_minor = index_to_minor(index);
 	vblk->disk->private_data = vblk;
 	vblk->disk->fops = &virtblk_fops;
-	vblk->disk->driverfs_dev = &vdev->dev;
 	vblk->disk->flags |= GENHD_FL_EXT_DEVT;
 	vblk->index = index;
 
@@ -732,7 +731,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 
 	virtio_device_ready(vdev);
 
-	add_disk(vblk->disk);
+	WARN_ON(device_add_disk(&vdev->dev, vblk->disk) != 0);
 	err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
 	if (err)
 		goto out_del_disk;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 83eb9e6bf8b0..2a5b21f8137e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1139,7 +1139,6 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 	gd->first_minor = minor;
 	gd->fops = &xlvbd_block_fops;
 	gd->private_data = info;
-	gd->driverfs_dev = &(info->xbdev->dev);
 	set_capacity(gd, capacity);
 
 	if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
@@ -2453,7 +2452,7 @@ static void blkfront_connect(struct blkfront_info *info)
 	for (i = 0; i < info->nr_rings; i++)
 		kick_pending_request_queues(&info->rinfo[i]);
 
-	add_disk(info->gd);
+	WARN_ON(device_add_disk(&info->xbdev->dev, info->gd) != 0);
 
 	info->is_ready = 1;
 }
diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index ef907fd5ba98..36eaccf572fb 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -1770,7 +1770,6 @@ static int ide_cd_probe(ide_drive_t *drive)
 	drive->driver_data = info;
 
 	g->minors = 1;
-	g->driverfs_dev = &drive->gendev;
 	g->flags = GENHD_FL_CD | GENHD_FL_REMOVABLE;
 	if (ide_cdrom_setup(drive)) {
 		put_device(&info->dev);
@@ -1780,7 +1779,7 @@ static int ide_cd_probe(ide_drive_t *drive)
 	ide_cd_read_toc(drive, &sense);
 	g->fops = &idecd_ops;
 	g->flags |= GENHD_FL_REMOVABLE | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
-	add_disk(g);
+	WARN_ON(device_add_disk(&drive->gendev, g) != 0);
 	return 0;
 
 out_free_disk:
diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
index 838996a0039e..640777188285 100644
--- a/drivers/ide/ide-gd.c
+++ b/drivers/ide/ide-gd.c
@@ -412,12 +412,11 @@ static int ide_gd_probe(ide_drive_t *drive)
 	set_capacity(g, ide_gd_capacity(drive));
 
 	g->minors = IDE_DISK_MINORS;
-	g->driverfs_dev = &drive->gendev;
 	g->flags |= GENHD_FL_EXT_DEVT;
 	if (drive->dev_flags & IDE_DFLAG_REMOVABLE)
 		g->flags = GENHD_FL_REMOVABLE;
 	g->fops = &ide_gd_ops;
-	add_disk(g);
+	WARN_ON(device_add_disk(&drive->gendev, g) != 0);
 	return 0;
 
 out_free_disk:
diff --git a/drivers/memstick/core/ms_block.c b/drivers/memstick/core/ms_block.c
index 84abf9d3c24e..3028a0f72adf 100644
--- a/drivers/memstick/core/ms_block.c
+++ b/drivers/memstick/core/ms_block.c
@@ -2146,7 +2146,6 @@ static int msb_init_disk(struct memstick_dev *card)
 	msb->disk->fops = &msb_bdops;
 	msb->disk->private_data = msb;
 	msb->disk->queue = msb->queue;
-	msb->disk->driverfs_dev = &card->dev;
 	msb->disk->flags |= GENHD_FL_EXT_DEVT;
 
 	capacity = msb->pages_in_block * msb->logical_block_count;
@@ -2163,7 +2162,7 @@ static int msb_init_disk(struct memstick_dev *card)
 		set_disk_ro(msb->disk, 1);
 
 	msb_start(card);
-	add_disk(msb->disk);
+	WARN_ON(device_add_disk(&card->dev, msb->disk) != 0);
 	dbg("Disk added");
 	return 0;
 
diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index 922a750640e8..b068f8aa9648 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -1244,7 +1244,6 @@ static int mspro_block_init_disk(struct memstick_dev *card)
 	msb->usage_count = 1;
 	msb->disk->private_data = msb;
 	msb->disk->queue = msb->queue;
-	msb->disk->driverfs_dev = &card->dev;
 
 	sprintf(msb->disk->disk_name, "mspblk%d", disk_id);
 
@@ -1256,7 +1255,7 @@ static int mspro_block_init_disk(struct memstick_dev *card)
 	set_capacity(msb->disk, capacity);
 	dev_dbg(&card->dev, "capacity set %ld\n", capacity);
 
-	add_disk(msb->disk);
+	WARN_ON(device_add_disk(&card->dev, msb->disk) != 0);
 	msb->active = 1;
 	return 0;
 
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 47bc87dafb00..a1aafd9a1731 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2237,7 +2237,6 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	md->disk->fops = &mmc_bdops;
 	md->disk->private_data = md;
 	md->disk->queue = md->queue.queue;
-	md->disk->driverfs_dev = parent;
 	set_disk_ro(md->disk, md->read_only || default_ro);
 	md->disk->flags = GENHD_FL_EXT_DEVT;
 	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
@@ -2423,7 +2422,7 @@ static int mmc_add_disk(struct mmc_blk_data *md)
 	int ret;
 	struct mmc_card *card = md->queue.card;
 
-	add_disk(md->disk);
+	WARN_ON(device_add_disk(&card->dev, md->disk) != 0);
 	md->force_ro.show = force_ro_show;
 	md->force_ro.store = force_ro_store;
 	sysfs_attr_init(&md->force_ro.attr);
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index f4701182b558..e37feb5c9d07 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -431,12 +431,10 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 		goto error4;
 	INIT_WORK(&new->work, mtd_blktrans_work);
 
-	gd->driverfs_dev = &new->mtd->dev;
-
 	if (new->readonly)
 		set_disk_ro(gd, 1);
 
-	add_disk(gd);
+	WARN_ON(device_add_disk(&new->mtd->dev, gd) != 0);
 
 	if (new->disk_attributes) {
 		ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c
index 91a336ea8c4f..475d07e3fc59 100644
--- a/drivers/nvdimm/blk.c
+++ b/drivers/nvdimm/blk.c
@@ -263,7 +263,6 @@ static int nd_blk_attach_disk(struct nd_namespace_common *ndns,
 		return -ENOMEM;
 	}
 
-	disk->driverfs_dev	= &ndns->dev;
 	disk->major		= nd_blk_major;
 	disk->first_minor	= 0;
 	disk->fops		= &nd_blk_fops;
@@ -272,7 +271,7 @@ static int nd_blk_attach_disk(struct nd_namespace_common *ndns,
 	disk->flags		= GENHD_FL_EXT_DEVT;
 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
 	set_capacity(disk, 0);
-	add_disk(disk);
+	WARN_ON(device_add_disk(&ndns->dev, disk) != 0);
 
 	if (nd_blk_meta_size(blk_dev)) {
 		int rc = nd_integrity_init(disk, nd_blk_meta_size(blk_dev));
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index efb2c1ceef98..46ff074b2389 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1245,7 +1245,6 @@ static int btt_blk_init(struct btt *btt)
 	}
 
 	nvdimm_namespace_disk_name(ndns, btt->btt_disk->disk_name);
-	btt->btt_disk->driverfs_dev = &btt->nd_btt->dev;
 	btt->btt_disk->major = btt_major;
 	btt->btt_disk->first_minor = 0;
 	btt->btt_disk->fops = &btt_fops;
@@ -1261,7 +1260,7 @@ static int btt_blk_init(struct btt *btt)
 	btt->btt_queue->queuedata = btt;
 
 	set_capacity(btt->btt_disk, 0);
-	add_disk(btt->btt_disk);
+	WARN_ON(device_add_disk(&btt->nd_btt->dev, btt->btt_disk) != 0);
 	if (btt_meta_size(btt)) {
 		int rc = nd_integrity_init(btt->btt_disk, btt_meta_size(btt));
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 7edf31671dab..75ab1da55724 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -235,7 +235,6 @@ static int pmem_attach_disk(struct device *dev,
 	disk->queue		= pmem->pmem_queue;
 	disk->flags		= GENHD_FL_EXT_DEVT;
 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
-	disk->driverfs_dev = dev;
 	set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
 	pmem->pmem_disk = disk;
 	devm_exit_badblocks(dev, &pmem->bb);
@@ -244,7 +243,7 @@ static int pmem_attach_disk(struct device *dev,
 	nvdimm_namespace_add_poison(ndns, &pmem->bb, pmem->data_offset);
 
 	disk->bb = &pmem->bb;
-	add_disk(disk);
+	WARN_ON(device_add_disk(dev, disk) != 0);
 	revalidate_disk(disk);
 
 	return 0;
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 504a6045985c..01c54f2f7202 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1186,7 +1186,6 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	disk->fops = &nvme_fops;
 	disk->private_data = ns;
 	disk->queue = ns->queue;
-	disk->driverfs_dev = ctrl->device;
 	disk->flags = GENHD_FL_EXT_DEVT;
 	sprintf(disk->disk_name, "nvme%dn%d", ctrl->instance, nsid);
 
@@ -1198,7 +1197,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	if (ns->type == NVME_NS_LIGHTNVM)
 		return;
 
-	add_disk(ns->disk);
+	WARN_ON(device_add_disk(ctrl->device, ns->disk));
 	if (sysfs_create_group(&disk_to_dev(ns->disk)->kobj,
 					&nvme_ns_attr_group))
 		pr_warn("%s: failed to create sysfs group for identification\n",
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index ef1d9fb06cab..1d18e31e86ae 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -45,7 +45,6 @@ int dasd_gendisk_alloc(struct dasd_block *block)
 	gdp->major = DASD_MAJOR;
 	gdp->first_minor = base->devindex << DASD_PARTN_BITS;
 	gdp->fops = &dasd_device_operations;
-	gdp->driverfs_dev = &base->cdev->dev;
 
 	/*
 	 * Set device name.
@@ -76,7 +75,7 @@ int dasd_gendisk_alloc(struct dasd_block *block)
 	gdp->queue = block->request_queue;
 	block->gdp = gdp;
 	set_capacity(block->gdp, 0);
-	add_disk(block->gdp);
+	WARN_ON(device_add_disk(&base->cdev->dev, block->gdp));
 	return 0;
 }
 
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index ce7b70181740..7d3d91553c7f 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -615,7 +615,6 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 	dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 	dev_info->gd->queue = dev_info->dcssblk_queue;
 	dev_info->gd->private_data = dev_info;
-	dev_info->gd->driverfs_dev = &dev_info->dev;
 	blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 	blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
 
@@ -655,7 +654,7 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 		goto put_dev;
 
 	get_device(&dev_info->dev);
-	add_disk(dev_info->gd);
+	WARN_ON(device_add_disk(&dev_info->dev, dev_info->gd) != 0);
 
 	switch (dev_info->segment_type) {
 		case SEG_TYPE_SR:
diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index 75d9896deccb..846c4ec4f811 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -512,7 +512,6 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 		goto out_queue;
 
 	rq->queuedata = scmdev;
-	bdev->gendisk->driverfs_dev = &scmdev->dev;
 	bdev->gendisk->private_data = scmdev;
 	bdev->gendisk->fops = &scm_blk_devops;
 	bdev->gendisk->queue = rq;
@@ -531,7 +530,7 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 
 	/* 512 byte sectors */
 	set_capacity(bdev->gendisk, scmdev->size >> 9);
-	add_disk(bdev->gendisk);
+	WARN_ON(device_add_disk(&scmdev->dev, bdev->gendisk) != 0);
 	return 0;
 
 out_queue:
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d749da765df1..1b06f3e6a210 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3012,7 +3012,6 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 
 	sd_revalidate_disk(gd);
 
-	gd->driverfs_dev = &sdp->sdev_gendev;
 	gd->flags = GENHD_FL_EXT_DEVT;
 	if (sdp->removable) {
 		gd->flags |= GENHD_FL_REMOVABLE;
@@ -3020,7 +3019,7 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 	}
 
 	blk_pm_runtime_init(sdp->request_queue, dev);
-	add_disk(gd);
+	WARN_ON(device_add_disk(&sdp->sdev_gendev, gd) != 0);
 	if (sdkp->capacity)
 		sd_dif_config_host(sdkp);
 
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 64c867405ad4..ab89f983862a 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -713,7 +713,6 @@ static int sr_probe(struct device *dev)
 	get_capabilities(cd);
 	sr_vendor_init(cd);
 
-	disk->driverfs_dev = &sdev->sdev_gendev;
 	set_capacity(disk, cd->capacity);
 	disk->private_data = &cd->driver;
 	disk->queue = sdev->request_queue;
@@ -730,7 +729,7 @@ static int sr_probe(struct device *dev)
 
 	dev_set_drvdata(dev, cd);
 	disk->flags |= GENHD_FL_REMOVABLE;
-	add_disk(disk);
+	WARN_ON(device_add_disk(&sdev->sdev_gendev, disk) != 0);
 
 	sdev_printk(KERN_DEBUG, sdev,
 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);

[PATCH 3/3] block: remove ->driverfs_dev

[Dan Williams]

Now that all drivers that specify a ->driverfs_dev have been converted
to device_add_disk(), the pointer can be removed from struct gendisk.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 block/genhd.c         |    5 ++---
 drivers/nvdimm/bus.c  |    2 +-
 include/linux/genhd.h |    4 +---
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 3fa2654ada52..d20f36bf42fa 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -797,10 +797,9 @@ void __init printk_all_partitions(void)
 			       , disk_name(disk, part->partno, name_buf),
 			       part->info ? part->info->uuid : "");
 			if (is_part0) {
-				if (disk->driverfs_dev != NULL &&
-				    disk->driverfs_dev->driver != NULL)
+				if (dev->parent && dev->parent->driver)
 					printk(" driver: %s\n",
-					      disk->driverfs_dev->driver->name);
+					      dev->parent->driver->name);
 				else
 					printk(" (driver?)\n");
 			} else
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 2b2181cdeb63..f2540bfaa65a 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -235,7 +235,7 @@ EXPORT_SYMBOL(__nd_driver_register);
 
 int nvdimm_revalidate_disk(struct gendisk *disk)
 {
-	struct device *dev = disk->driverfs_dev;
+	struct device *dev = disk_to_dev(disk)->parent;
 	struct nd_region *nd_region = to_nd_region(dev->parent);
 	const char *pol = nd_region->ro ? "only" : "write";
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6fa03fe589ad..0c065e8549f1 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -204,7 +204,6 @@ struct gendisk {
 	void *private_data;
 
 	int flags;
-	struct device *driverfs_dev;  // FIXME: remove
 	struct kobject *slave_dir;
 
 	struct timer_rand_state *random;
@@ -434,8 +433,7 @@ extern void part_round_stats(int cpu, struct hd_struct *part);
 extern int device_add_disk(struct device *parent, struct gendisk *disk);
 static inline void add_disk(struct gendisk *disk)
 {
-	/* temporary while we convert callers to device_add_disk */
-	WARN_ON(device_add_disk(disk->driverfs_dev, disk) != 0);
+	WARN_ON(device_add_disk(NULL, disk) != 0);
 }
 
 extern void del_gendisk(struct gendisk *gp);

Re: [PATCH 0/3] Introduce device_add_disk() to kill gendisk.driverfs_dev

[Dan Williams]

On Thu, Feb 25, 2016 at 12:04 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> Answer the "// FIXME: remove" include/linux/genhd.h.  This should be
> functionally equivalent to the previous state.  Now that the WARN_ON()
> for the registration failure case is up-levelled to some drivers, they
> can take on the follow on work to handle device_add_disk() failures.
>
> Note, a full run from the kbuild robot is still pending.  I'll post v2
> if it reports anything against this set on top of current -next.
>
> ---
>
> Dan Williams (3):
>       block: introduce device_add_disk()
>       block: convert to device_add_disk()
>       block: remove ->driverfs_dev
>

Yes, no, maybe so for 4.6?

Re: [PATCH 1/3] block: introduce device_add_disk()

[Christoph Hellwig]

>  /**
> - * add_disk - add partitioning information to kernel list
> + * device_add_disk - add partitioning information to kernel list
> + * @parent: parent device for the disk
>   * @disk: per-device partitioning information
>   *
>   * This function registers the partitioning information in @disk
> @@ -581,7 +582,7 @@ exit:
>   *
>   * FIXME: error handling
>   */
> -void add_disk(struct gendisk *disk)
> +int device_add_disk(struct device *parent, struct gendisk *disk)
>  {
>  	struct backing_dev_info *bdi;
>  	dev_t devt;
> @@ -597,10 +598,8 @@ void add_disk(struct gendisk *disk)
>  	disk->flags |= GENHD_FL_UP;
>  
>  	retval = blk_alloc_devt(&disk->part0, &devt);
> -	if (retval) {
> -		WARN_ON(1);
> -		return;
> -	}
> +	if (retval)
> +		return retval;
>  	disk_to_dev(disk)->devt = devt;
>  
>  	/* ->major and ->first_minor aren't supposed to be
> @@ -617,7 +616,7 @@ void add_disk(struct gendisk *disk)
>  
>  	blk_register_region(disk_devt(disk), disk->minors, NULL,
>  			    exact_match, exact_lock, disk);
> -	register_disk(disk);
> +	register_disk(parent, disk);
>  	blk_register_queue(disk);
>  
>  	/*
> @@ -628,12 +627,11 @@ void add_disk(struct gendisk *disk)
>  
>  	retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
>  				   "bdi");
> -	WARN_ON(retval);
> -
>  	disk_add_events(disk);
>  	blk_integrity_add(disk);
> +	return retval;

How are the callers expected to unwind after already having added the
disk?

Re: [PATCH 1/3] block: introduce device_add_disk()

[Dan Williams]

On Thu, Mar 10, 2016 at 12:09 AM, Christoph Hellwig <hch@lst.de> wrote:
>>  /**
>> - * add_disk - add partitioning information to kernel list
>> + * device_add_disk - add partitioning information to kernel list
>> + * @parent: parent device for the disk
>>   * @disk: per-device partitioning information
>>   *
>>   * This function registers the partitioning information in @disk
>> @@ -581,7 +582,7 @@ exit:
>>   *
>>   * FIXME: error handling
>>   */
>> -void add_disk(struct gendisk *disk)
>> +int device_add_disk(struct device *parent, struct gendisk *disk)
>>  {
>>       struct backing_dev_info *bdi;
>>       dev_t devt;
>> @@ -597,10 +598,8 @@ void add_disk(struct gendisk *disk)
>>       disk->flags |= GENHD_FL_UP;
>>
>>       retval = blk_alloc_devt(&disk->part0, &devt);
>> -     if (retval) {
>> -             WARN_ON(1);
>> -             return;
>> -     }
>> +     if (retval)
>> +             return retval;
>>       disk_to_dev(disk)->devt = devt;
>>
>>       /* ->major and ->first_minor aren't supposed to be
>> @@ -617,7 +616,7 @@ void add_disk(struct gendisk *disk)
>>
>>       blk_register_region(disk_devt(disk), disk->minors, NULL,
>>                           exact_match, exact_lock, disk);
>> -     register_disk(disk);
>> +     register_disk(parent, disk);
>>       blk_register_queue(disk);
>>
>>       /*
>> @@ -628,12 +627,11 @@ void add_disk(struct gendisk *disk)
>>
>>       retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
>>                                  "bdi");
>> -     WARN_ON(retval);
>> -
>>       disk_add_events(disk);
>>       blk_integrity_add(disk);
>> +     return retval;
>
> How are the callers expected to unwind after already having added the
> disk?

True, I overlooked making add_disk() unwind-able, will re-spin...

Re: [PATCH 1/3] block: introduce device_add_disk()

[Christoph Hellwig]

On Thu, Mar 10, 2016 at 07:15:19AM -0800, Dan Williams wrote:
> > How are the callers expected to unwind after already having added the
> > disk?
> 
> True, I overlooked making add_disk() unwind-able, will re-spin...

I think this will take more work than we can finish in the next
days.  It would be good to simply respin it without adding the error
propagation.

Re: [PATCH 1/3] block: introduce device_add_disk()

[Dan Williams]

On Thu, Mar 10, 2016 at 7:18 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Thu, Mar 10, 2016 at 07:15:19AM -0800, Dan Williams wrote:
>> > How are the callers expected to unwind after already having added the
>> > disk?
>>
>> True, I overlooked making add_disk() unwind-able, will re-spin...
>
> I think this will take more work than we can finish in the next
> days.  It would be good to simply respin it without adding the error
> propagation.

Sounds good.