diff options
| -rw-r--r-- | Documentation/block/capability.rst | 16 | ||||
| -rw-r--r-- | include/linux/genhd.h | 69 |
2 files changed, 62 insertions, 23 deletions
diff --git a/Documentation/block/capability.rst b/Documentation/block/capability.rst index 2cf258d64bbe..160a5148b915 100644 --- a/Documentation/block/capability.rst +++ b/Documentation/block/capability.rst @@ -2,17 +2,9 @@ Generic Block Device Capability =============================== -This file documents the sysfs file block/<disk>/capability +This file documents the sysfs file ``block/<disk>/capability``. -capability is a hex word indicating which capabilities a specific disk -supports. For more information on bits not listed here, see -include/linux/genhd.h +``capability`` is a bitfield, printed in hexadecimal, indicating which +capabilities a specific block device supports: -GENHD_FL_MEDIA_CHANGE_NOTIFY ----------------------------- - -Value: 4 - -When this bit is set, the disk supports Asynchronous Notification -of media change events. These events will be broadcast to user -space via kernel uevent. +.. kernel-doc:: include/linux/genhd.h diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 6fbe58538ad6..e7244fb6b6ad 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -133,17 +133,64 @@ struct hd_struct { struct rcu_work rcu_work; }; -#define GENHD_FL_REMOVABLE 1 -/* 2 is unused */ -#define GENHD_FL_MEDIA_CHANGE_NOTIFY 4 -#define GENHD_FL_CD 8 -#define GENHD_FL_UP 16 -#define GENHD_FL_SUPPRESS_PARTITION_INFO 32 -#define GENHD_FL_EXT_DEVT 64 /* allow extended devt */ -#define GENHD_FL_NATIVE_CAPACITY 128 -#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 256 -#define GENHD_FL_NO_PART_SCAN 512 -#define GENHD_FL_HIDDEN 1024 +/** + * DOC: genhd capability flags + * + * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device + * gives access to removable media. + * When set, the device remains present even when media is not + * inserted. + * Must not be set for devices which are removed entirely when the + * media is removed. + * + * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style + * 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(). + * Used for the null block device and some MMC devices. + * + * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended + * dynamic ``dev_t``, i.e. it wants extended device numbers + * (``BLOCK_EXT_MAJOR``). + * This affects the maximum number of partitions. + * + * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the + * partition table, the device's capacity has been extended to its + * native capacity; i.e. the device has hidden capacity used by one + * of the partitions (this is a flag used so that native capacity is + * only ever unlocked once). + * + * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is + * blocked whenever a writer holds an exclusive lock. + * + * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled. + * Used for loop devices in their default settings and some MMC + * devices. + * + * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it + * doesn't produce events, doesn't appear in sysfs, and doesn't have + * an associated ``bdev``. + * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and + * ``GENHD_FL_NO_PART_SCAN``. + * Used for multipath devices. + */ +#define GENHD_FL_REMOVABLE 0x0001 +/* 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 +#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 0x0100 +#define GENHD_FL_NO_PART_SCAN 0x0200 +#define GENHD_FL_HIDDEN 0x0400 enum { DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */ |