block: first batch of add_disk() error handling conversions

This v2 drops two of the scsi patches which  Christoph pointed out were
not needed. It also fixes the nvme driver change to account for the
missing put of the ctrl. It also just appends the commits with the
respective reviewed tags. I've also dropped the mmc and dm patches
from this series as that is still pending discussion. I'll roll that
into the my next series after discussion is done.

The only patch which goes without a review tag is the nvme driver change.

These changes go rebased on Jen's latest axboe/for-next. The respective
full queue of my changes can be found on my git branch [0].

[0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/log/?h=20210827-for-axboe-add-disk-error-handling-next

Luis Chamberlain (6):
  scsi/sd: add error handling support for add_disk()
  scsi/sr: add error handling support for add_disk()
  nvme: add error handling support for add_disk()
  md: add error handling support for add_disk()
  loop: add error handling support for add_disk()
  nbd: add error handling support for add_disk()

 drivers/block/loop.c     | 9 ++++++++-
 drivers/block/nbd.c      | 6 +++++-
 drivers/md/md.c          | 7 ++++++-
 drivers/nvme/host/core.c | 9 ++++++++-
 drivers/scsi/sd.c        | 6 +++++-
 drivers/scsi/sr.c        | 5 ++++-
 6 files changed, 36 insertions(+), 6 deletions(-)

-- 
2.30.2

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

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/scsi/sd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 610ebba0d66e..8c1273fff23e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c

@@ -3487,7 +3487,11 @@ static int sd_probe(struct device *dev)
 		pm_runtime_set_autosuspend_delay(dev,
 			sdp->host->hostt->rpm_autosuspend_delay);
 	}
-	device_add_disk(dev, gd, NULL);
+
+	error = device_add_disk(dev, gd, NULL);
+	if (error)
+		goto out_free_index;
+
 	if (sdkp->capacity)
 		sd_dif_config_host(sdkp);
 

-- 
2.30.2

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

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/block/nbd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 5170a630778d..741365295157 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c

@@ -1757,7 +1757,9 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 	disk->fops = &nbd_fops;
 	disk->private_data = nbd;
 	sprintf(disk->disk_name, "nbd%d", index);
-	add_disk(disk);
+	err = add_disk(disk);
+	if (err)
+		goto out_err_disk;
 
 	/*
 	 * Now publish the device.

@@ -1766,6 +1768,8 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 	nbd_total_devices++;
 	return nbd;
 
+out_err_disk:
+	blk_cleanup_disk(disk);
 out_free_idr:
 	mutex_lock(&nbd_index_mutex);
 	idr_remove(&nbd_index_idr, index);

-- 
2.30.2

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

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/block/loop.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index fa1c298a8cfb..b8b9e2349e77 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c

@@ -2393,10 +2393,17 @@ static int loop_add(int i)
 	disk->events		= DISK_EVENT_MEDIA_CHANGE;
 	disk->event_flags	= DISK_EVENT_FLAG_UEVENT;
 	sprintf(disk->disk_name, "loop%d", i);
-	add_disk(disk);
+
+	err = add_disk(disk);
+	if (err)
+		goto out_cleanup_disk;
+
 	mutex_unlock(&loop_ctl_mutex);
+
 	return i;
 
+out_cleanup_disk:
+	blk_cleanup_disk(disk);
 out_cleanup_tags:
 	blk_mq_free_tag_set(&lo->tag_set);
 out_free_idr:

-- 
2.30.2

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

We just do the unwinding of what was not done before, and are
sure to unlock prior to bailing.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/md/md.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index ae8fe54ea358..5c0d3536d7c7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -5704,7 +5704,11 @@ static int md_alloc(dev_t dev, char *name)
 	 * through to md_open, so make sure it doesn't get too far
 	 */
 	mutex_lock(&mddev->open_mutex);
-	add_disk(disk);
+	error = add_disk(disk);
+	if (error) {
+		blk_cleanup_disk(disk);
+		goto abort_unlock;
+	}
 
 	error = kobject_add(&mddev->kobj, &disk_to_dev(disk)->kobj, "%s", "md");
 	if (error) {

@@ -5718,6 +5722,7 @@ static int md_alloc(dev_t dev, char *name)
 	if (mddev->kobj.sd &&
 	    sysfs_create_group(&mddev->kobj, &md_bitmap_group))
 		pr_debug("pointless warning\n");
+ abort_unlock:
 	mutex_unlock(&mddev->open_mutex);
  abort:
 	mutex_unlock(&disks_mutex);

-- 
2.30.2

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/nvme/host/core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 8679a108f571..687d3be563a3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c

@@ -3763,7 +3763,9 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 
 	nvme_get_ctrl(ctrl);
 
-	device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups);
+	if (device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups))
+		goto out_cleanup_ns_from_list;
+
 	if (!nvme_ns_head_multipath(ns->head))
 		nvme_add_ns_cdev(ns);
 

@@ -3773,6 +3775,11 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 
 	return;
 
+ out_cleanup_ns_from_list:
+	nvme_put_ctrl(ctrl);
+	down_write(&ctrl->namespaces_rwsem);
+	list_del_init(&ns->list);
+	up_write(&ctrl->namespaces_rwsem);
  out_unlink_ns:
 	mutex_lock(&ctrl->subsys->lock);
 	list_del_rcu(&ns->siblings);

-- 
2.30.2

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

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/scsi/sr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 2942a4ec9bdd..72fd21844367 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c

@@ -779,7 +779,10 @@ static int sr_probe(struct device *dev)
 	dev_set_drvdata(dev, cd);
 	disk->flags |= GENHD_FL_REMOVABLE;
 	sr_revalidate_disk(cd);
-	device_add_disk(&sdev->sdev_gendev, disk, NULL);
+
+	error = device_add_disk(&sdev->sdev_gendev, disk, NULL);
+	if (error)
+		goto fail_minor;
 
 	sdev_printk(KERN_DEBUG, sdev,
 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);

-- 
2.30.2

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>