linux/block/Kconfig

#
# Block layer core configuration
#
menuconfig BLOCK
       bool "Enable the block layer" if EXPERT
       default y
       select SBITMAP
       select SRCU
       help
	 Provide block layer support for the kernel.

	 Disable this option to remove the block layer support from the
	 kernel. This may be useful for embedded devices.

	 If this option is disabled:

	   - block device files will become unusable
	   - some filesystems (such as ext3) will become unavailable.

	 Also, SCSI character devices and USB storage will be disabled since
	 they make use of various block layer definitions and facilities.

	 Say Y here unless you know you really don't want to mount disks and
	 suchlike.

if BLOCK

config LBDAF
	bool "Support for large (2TB+) block devices and files"
	depends on !64BIT
	default y
	help
	  Enable block devices or files of size 2TB and larger.

	  This option is required to support the full capacity of large
	  (2TB+) block devices, including RAID, disk, Network Block Device,
	  Logical Volume Manager (LVM) and loopback.
	
	  This option also enables support for single files larger than
	  2TB.

	  The ext4 filesystem requires that this feature be enabled in
	  order to support filesystems that have the huge_file feature
	  enabled.  Otherwise, it will refuse to mount in the read-write
	  mode any filesystems that use the huge_file feature, which is
	  enabled by default by mke2fs.ext4.

	  The GFS2 filesystem also requires this feature.

	  If unsure, say Y.

config BLK_DEV_BSG
	bool "Block layer SG support v4"
	default y
	help
	  Saying Y here will enable generic SG (SCSI generic) v4 support
	  for any block device.

	  Unlike SG v3 (aka block/scsi_ioctl.c drivers/scsi/sg.c), SG v4
	  can handle complicated SCSI commands: tagged variable length cdbs
	  with bidirectional data transfers and generic request/response
	  protocols (e.g. Task Management Functions and SMP in Serial
	  Attached SCSI).

	  This option is required by recent UDEV versions to properly
	  access device serial numbers, etc.

	  If unsure, say Y.

config BLK_DEV_BSGLIB
	bool "Block layer SG support v4 helper lib"
	default n
	select BLK_DEV_BSG
	help
	  Subsystems will normally enable this if needed. Users will not
	  normally need to manually enable this.

	  If unsure, say N.

config BLK_DEV_INTEGRITY
	bool "Block layer data integrity support"
	select CRC_T10DIF if BLK_DEV_INTEGRITY
	---help---
	Some storage devices allow extra information to be
	stored/retrieved to help protect the data.  The block layer
	data integrity option provides hooks which can be used by
	filesystems to ensure better data integrity.

	Say yes here if you have a storage device that provides the
	T10/SCSI Data Integrity Field or the T13/ATA External Path
	Protection.  If in doubt, say N.

config BLK_DEV_ZONED
	bool "Zoned block device support"
	---help---
	Block layer zoned block device support. This option enables
	support for ZAC/ZBC host-managed and host-aware zoned block devices.

	Say yes here if you have a ZAC or ZBC storage device.

config BLK_DEV_THROTTLING
	bool "Block layer bio throttling support"
	depends on BLK_CGROUP=y
	default n
	---help---
	Block layer bio throttling support. It can be used to limit
	the IO rate to a device. IO rate policies are per cgroup and
	one needs to mount and use blkio cgroup controller for creating
	cgroups and specifying per device IO rate policies.

	See Documentation/cgroups/blkio-controller.txt for more information.

config BLK_CMDLINE_PARSER
	bool "Block device command line partition parser"
	default n
	---help---
	Enabling this option allows you to specify the partition layout from
	the kernel boot args.  This is typically of use for embedded devices
	which don't otherwise have any standardized method for listing the
	partitions on a block device.

	See Documentation/block/cmdline-partition.txt for more information.

config BLK_WBT
	bool "Enable support for block device writeback throttling"
	default n
	---help---
	Enabling this option enables the block layer to throttle buffered
	background writeback from the VM, making it more smooth and having
	less impact on foreground operations. The throttling is done
	dynamically on an algorithm loosely based on CoDel, factoring in
	the realtime performance of the disk.

config BLK_WBT_SQ
	bool "Single queue writeback throttling"
	default n
	depends on BLK_WBT
	---help---
	Enable writeback throttling by default on legacy single queue devices

config BLK_WBT_MQ
	bool "Multiqueue writeback throttling"
	default y
	depends on BLK_WBT
	---help---
	Enable writeback throttling by default on multiqueue devices.
	Multiqueue currently doesn't have support for IO scheduling,
	enabling this option is recommended.

config BLK_DEBUG_FS
	bool "Block layer debugging information in debugfs"
	default y
	depends on DEBUG_FS
	---help---
	Include block layer debugging information in debugfs. This information
	is mostly useful for kernel developers, but it doesn't incur any cost
	at runtime.

	Unless you are building a kernel for a tiny system, you should
	say Y here.

menu "Partition Types"

source "block/partitions/Kconfig"

endmenu

endif # BLOCK

config BLOCK_COMPAT
	bool
	depends on BLOCK && COMPAT
	default y

config BLK_MQ_PCI
	bool
	depends on BLOCK && PCI
	default y

source block/Kconfig.iosched