block: remove GENHD_FL_UP

Just check inode_unhashed on the whole device bdev inode instead,
and provide a helper to check for that information.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210809064028.1198327-9-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -77,7 +77,8 @@ bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
 	 * initial capacity during probing.
 	 */
 	if (size == capacity ||
-	    (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
+	    !disk_live(disk) ||
+	    (disk->flags & GENHD_FL_HIDDEN))
 		return false;
 
 	pr_info("%s: detected capacity change from %lld to %lld\n",
@@ -527,8 +528,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk,
 		disk->flags |= GENHD_FL_EXT_DEVT;
 	}
 
-	disk->flags |= GENHD_FL_UP;
-
 	disk_alloc_events(disk);
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
@@ -597,7 +596,6 @@ void del_gendisk(struct gendisk *disk)
 
 	mutex_lock(&disk->open_mutex);
 	remove_inode_hash(disk->part0->bd_inode);
-	disk->flags &= ~GENHD_FL_UP;
 	blk_drop_partitions(disk);
 	mutex_unlock(&disk->open_mutex);
 

block/partitions/core.c

@@ -459,7 +459,7 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 	int ret;
 
 	mutex_lock(&disk->open_mutex);
-	if (!(disk->flags & GENHD_FL_UP)) {
+	if (!disk_live(disk)) {
 		ret = -ENXIO;
 		goto out;
 	}
@@ -669,7 +669,7 @@ int bdev_disk_changed(struct gendisk *disk, bool invalidate)
 
 	lockdep_assert_held(&disk->open_mutex);
 
-	if (!(disk->flags & GENHD_FL_UP))
+	if (!disk_live(disk))
 		return -ENXIO;
 
 rescan:

drivers/md/md.h

@@ -764,9 +764,7 @@ struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
 
 static inline bool is_mddev_broken(struct md_rdev *rdev, const char *md_type)
 {
-	int flags = rdev->bdev->bd_disk->flags;
-
-	if (!(flags & GENHD_FL_UP)) {
+	if (!disk_live(rdev->bdev->bd_disk)) {
 		if (!test_and_set_bit(MD_BROKEN, &rdev->mddev->flags))
 			pr_warn("md: %s: %s array has a missing/failed member\n",
 				mdname(rdev->mddev), md_type);

drivers/nvme/host/core.c

@@ -1822,7 +1822,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
 static inline bool nvme_first_scan(struct gendisk *disk)
 {
 	/* nvme_alloc_ns() scans the disk prior to adding it */
-	return !(disk->flags & GENHD_FL_UP);
+	return !disk_live(disk);
 }
 
 static void nvme_set_chunk_sectors(struct nvme_ns *ns, struct nvme_id_ns *id)

fs/block_dev.c

@@ -1218,7 +1218,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 
 	mutex_lock(&disk->open_mutex);
 	ret = -ENXIO;
-	if (!(disk->flags & GENHD_FL_UP))
+	if (!disk_live(disk))
 		goto abort_claiming;
 	if (bdev_is_partition(bdev))
 		ret = blkdev_get_part(bdev, mode);

include/linux/genhd.h

@@ -60,9 +60,6 @@ struct partition_meta_info {
  * device.
  * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
  *
- * ``GENHD_FL_UP`` (0x0010): indicates that the block device is "up",
- * with a similar meaning to network interfaces.
- *
  * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
  * partition information in ``/proc/partitions`` or in the output of
  * printk_all_partitions().
@@ -97,7 +94,6 @@ struct partition_meta_info {
 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
 #define GENHD_FL_CD				0x0008
-#define GENHD_FL_UP				0x0010
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
 #define GENHD_FL_NATIVE_CAPACITY		0x0080
@@ -178,6 +174,11 @@ struct gendisk {
 	u64 diskseq;
 };
 
+static inline bool disk_live(struct gendisk *disk)
+{
+	return !inode_unhashed(disk->part0->bd_inode);
+}
+
 /*
  * The gendisk is refcounted by the part0 block_device, and the bd_device
  * therein is also used for device model presentation in sysfs.