block: allow partitions on host aware zone devices

Host-aware SMR drives can be used with the commands to explicitly manage zone state, but they can also be used as normal disks. In the former case it makes perfect sense to allow partitions on them, in the latter it does not, just like for host managed devices. Add a check to add_partition to allow partitions on host aware devices, but give up any zone management capabilities in that case, which also catches the previously missed case of adding a partition vs just scanning it. Because sd can rescan the attribute at runtime it needs to check if a disk has partitions, for which a new helper is added to genhd.h.

Christoph Hellwig committed 6 years ago

Commit b7205301 parent ad6bf883 files · +39 −8Browse files

Showing the changes to include/linux (1 of 3 files). Show all

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include/linux/genhd.h+12−0

@@ -245,6 +245,18 @@ static inline bool disk_part_scan_enabled(struct gendisk *disk) · 244 unmodified lines
245	!(disk->flags & GENHD_FL_NO_PART_SCAN);	245	!(disk->flags & GENHD_FL_NO_PART_SCAN);
246	}	246	}
247		247
		248	static inline bool disk_has_partitions(struct gendisk *disk)
		249	{
		250	bool ret = false;
		251
		252	rcu_read_lock();
		253	if (rcu_dereference(disk->part_tbl)->len > 1)
		254	ret = true;
		255	rcu_read_unlock();
		256
		257	return ret;
		258	}
		259
248	static inline dev_t disk_devt(struct gendisk *disk)	260	static inline dev_t disk_devt(struct gendisk *disk)
249	{	261	{
250	return MKDEV(disk->major, disk->first_minor);	262	return MKDEV(disk->major, disk->first_minor);