## 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_SCSI_REQUEST	bool config BLK_DEV_BSG	bool "Block layer SG support v4"	default y	select BLK_SCSI_REQUEST	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	select BLK_SCSI_REQUEST	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_DEV_THROTTLING_LOW	bool "Block throttling .low limit interface support (EXPERIMENTAL)"	depends on BLK_DEV_THROTTLING	default n	---help---	Add .low limit interface for block throttling. The low limit is a best	effort limit to prioritize cgroups. Depending on the setting, the limit	can be used to protect cgroups in terms of bandwidth/iops and better	utilize disk resource. 	Note, this is an experimental interface and could be changed someday. 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. config BLK_SED_OPAL	bool "Logic for interfacing with Opal enabled SEDs"	---help---	Builds Logic for interfacing with Opal enabled controllers.	Enabling this option enables users to setup/unlock/lock	Locking ranges for SED devices using the Opal protocol. 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 config BLK_MQ_VIRTIO	bool	depends on BLOCK && VIRTIO	default y source block/Kconfig.iosched