[PATCH v1 5/8] block: add initial error handling for *add_disk()* and friends

From: Luis Chamberlain
Date: Wed May 12 2021 - 03:02:15 EST

This adds error handling to the *add_disk*() callers and the functions
it depends on. This is initial work as drivers are not converted. That
is separate work.

Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
block/blk-integrity.c | 12 ++--
block/blk-sysfs.c | 5 +-
block/blk.h | 5 +-
block/genhd.c | 152 +++++++++++++++++++++++++++++-------------
include/linux/genhd.h | 14 ++--
5 files changed, 127 insertions(+), 61 deletions(-)

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 410da060d1f5..e46f47f2dec9 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -431,13 +431,17 @@ 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;
+
+ ret = kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
+ &disk_to_dev(disk)->kobj, "%s", "integrity");
+ if (ret)
+ return ret;

kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
+ return 0;
}

void blk_integrity_del(struct gendisk *disk)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index e03bedf180ab..8a0978a0623c 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -862,9 +862,10 @@ int blk_register_queue(struct gendisk *disk)
if (WARN_ON(!q))
return -ENXIO;

- WARN_ONCE(blk_queue_registered(q),
+ if (WARN_ONCE(blk_queue_registered(q),
"%s is registering an already registered queue\n",
- kobject_name(&dev->kobj));
+ kobject_name(&dev->kobj)))
+ return -ENXIO;

/*
* SCSI probing may synchronously create and destroy a lot of
diff --git a/block/blk.h b/block/blk.h
index 8b3591aee0a5..01ec7aba8d70 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 *);
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)
{
diff --git a/block/genhd.c b/block/genhd.c
index baa68192ebb3..eafcd256fc6f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -37,8 +37,8 @@ static DEFINE_IDA(ext_devt_ida);

static void disk_check_events(struct disk_events *ev,
unsigned int *clearing_ptr);
-static void disk_alloc_events(struct gendisk *disk);
-static void disk_add_events(struct gendisk *disk);
+static int disk_alloc_events(struct gendisk *disk);
+static int disk_add_events(struct gendisk *disk);
static void disk_del_events(struct gendisk *disk);
static void disk_release_events(struct gendisk *disk);

@@ -494,8 +494,9 @@ static void unregister_disk(struct gendisk *disk)
disk_invalidate(disk);
}

-static void register_disk(struct device *parent, struct gendisk *disk,
- const struct attribute_group **groups)
+static int __must_check register_disk(struct device *parent,
+ struct gendisk *disk,
+ const struct attribute_group **groups)
{
struct device *ddev = disk_to_dev(disk);
int err;
@@ -511,15 +512,20 @@ static void register_disk(struct device *parent, struct gendisk *disk,
WARN_ON(ddev->groups);
ddev->groups = groups;
}
- if (device_add(ddev))
- return;
+ err = device_add(ddev);
+ if (err) {
+ /*
+ * We don't put_device(ddev), the driver is responsible to
+ * issue the last put_device(ddev), however it instead uses
+ * put_disk().
+ */
+ return err;
+ }
if (!sysfs_deprecated) {
err = sysfs_create_link(block_depr, &ddev->kobj,
kobject_name(&ddev->kobj));
- if (err) {
- device_del(ddev);
- return;
- }
+ if (err)
+ goto exit_del_device;
}

/*
@@ -534,7 +540,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);

if (disk->flags & GENHD_FL_HIDDEN)
- return;
+ return 0;

disk_scan_partitions(disk);
disk_announce(disk);
@@ -543,8 +549,19 @@ static void register_disk(struct device *parent, struct gendisk *disk,
err = sysfs_create_link(&ddev->kobj,
&disk->queue->backing_dev_info->dev->kobj,
"bdi");
- WARN_ON(err);
+ if (WARN_ON(err))
+ goto exit_del_block_depr;
}
+ return 0;
+
+exit_del_block_depr:
+ unregister_disk_partitions(disk);
+ if (!sysfs_deprecated)
+ sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
+exit_del_device:
+ device_del(ddev);
+
+ return err;
}

/**
@@ -557,20 +574,24 @@ static void register_disk(struct device *parent, struct gendisk *disk,
* This function registers the partitioning information in @disk
* with the kernel.
*
- * FIXME: error handling
*/
-static void __device_add_disk(struct device *parent, struct gendisk *disk,
- const struct attribute_group **groups,
- bool register_queue)
+static int __device_add_disk(struct device *parent, struct gendisk *disk,
+ const struct attribute_group **groups,
+ bool register_queue)
{
dev_t devt;
int retval;

/*
* Take an extra ref on queue which will be put on disk_release()
- * so that it sticks around as long as @disk is there.
+ * so that it sticks around as long as @disk is there. The driver
+ * must call blk_cleanup_queue() and then put_disk() on error from
+ * this function.
*/
- WARN_ON_ONCE(!blk_get_queue(disk->queue));
+ if (WARN_ON_ONCE(!blk_get_queue(disk->queue))) {
+ disk->queue = NULL;
+ return -ESHUTDOWN;
+ }

/*
* The disk queue should now be all set with enough information about
@@ -585,21 +606,24 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
* be accompanied with EXT_DEVT flag. Make sure all
* parameters make sense.
*/
- WARN_ON(disk->minors && !(disk->major || disk->first_minor));
- WARN_ON(!disk->minors &&
- !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
+ if (WARN_ON(disk->minors && !(disk->major || disk->first_minor)))
+ return -EINVAL;
+ if (WARN_ON(!disk->minors &&
+ !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN))))
+ return -EINVAL;

disk->flags |= GENHD_FL_UP;

retval = blk_alloc_devt(disk->part0, &devt);
- if (retval) {
- WARN_ON(1);
- return;
- }
+ if (WARN_ON(retval))
+ return retval;
+
disk->major = MAJOR(devt);
disk->first_minor = MINOR(devt);

- disk_alloc_events(disk);
+ retval = disk_alloc_events(disk);
+ if (retval)
+ goto exit_blk_free_devt;

if (disk->flags & GENHD_FL_HIDDEN) {
/*
@@ -611,34 +635,62 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
} else {
struct backing_dev_info *bdi = disk->queue->backing_dev_info;
struct device *dev = disk_to_dev(disk);
- int ret;

/* Register BDI before referencing it from bdev */
dev->devt = devt;
- ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
- WARN_ON(ret);
+ retval = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
+ if (WARN_ON(retval))
+ goto exit_disk_release_events;
bdi_set_owner(bdi, dev);
bdev_add(disk->part0, devt);
}
- register_disk(parent, disk, groups);
- if (register_queue)
- blk_register_queue(disk);
+ retval = register_disk(parent, disk, groups);
+ if (retval)
+ goto exit_unregister_bdi;
+
+ if (register_queue) {
+ retval = blk_register_queue(disk);
+ if (retval)
+ goto exit_unregister_disk;
+ }

- disk_add_events(disk);
- blk_integrity_add(disk);
+ retval = disk_add_events(disk);
+ if (retval)
+ goto exit_unregister_disk;
+
+ retval = blk_integrity_add(disk);
+ if (retval)
+ goto exit_del_events;
+
+ return 0;
+exit_del_events:
+ disk_del_events(disk);
+exit_unregister_disk:
+ unregister_disk(disk);
+ return retval;
+
+exit_unregister_bdi:
+ if (disk->queue && !(disk->flags & GENHD_FL_HIDDEN))
+ bdi_unregister(disk->queue->backing_dev_info);
+exit_disk_release_events:
+ disk_release_events(disk);
+exit_blk_free_devt:
+ blk_free_devt(disk_devt(disk));
+
+ return retval;
}

-void device_add_disk(struct device *parent, struct gendisk *disk,
- const struct attribute_group **groups)
+int device_add_disk(struct device *parent, struct gendisk *disk,
+ const struct attribute_group **groups)

{
- __device_add_disk(parent, disk, groups, true);
+ return __device_add_disk(parent, disk, groups, true);
}
EXPORT_SYMBOL(device_add_disk);

-void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
+int device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
{
- __device_add_disk(parent, disk, NULL, false);
+ return __device_add_disk(parent, disk, NULL, false);
}
EXPORT_SYMBOL(device_add_disk_no_queue_reg);

@@ -1817,17 +1869,17 @@ 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.
*/
-static void disk_alloc_events(struct gendisk *disk)
+static 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);
@@ -1839,17 +1891,23 @@ static void disk_alloc_events(struct gendisk *disk)
INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);

disk->ev = ev;
+
+ return 0;
}

-static void disk_add_events(struct gendisk *disk)
+static int disk_add_events(struct gendisk *disk)
{
- /* FIXME: error handling */
- if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
+ int ret;
+
+ ret = sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
+ if (ret < 0) {
pr_warn("%s: failed to create sysfs files for events\n",
disk->disk_name);
+ return ret;
+ }

if (!disk->ev)
- return;
+ return 0;

mutex_lock(&disk_events_mutex);
list_add_tail(&disk->ev->node, &disk_events);
@@ -1860,6 +1918,8 @@ static void disk_add_events(struct gendisk *disk)
* unblock kicks it into action.
*/
__disk_unblock_events(disk, true);
+
+ return 0;
}

static void disk_del_events(struct gendisk *disk)
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 7e9660ea967d..5a23d97ccb90 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -205,16 +205,16 @@ 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)
+extern 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 device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
-static inline void add_disk_no_queue_reg(struct gendisk *disk)
+extern int device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
+static inline int add_disk_no_queue_reg(struct gendisk *disk)
{
- device_add_disk_no_queue_reg(NULL, disk);
+ return device_add_disk_no_queue_reg(NULL, disk);
}

extern void del_gendisk(struct gendisk *gp);
--
2.30.2