# Block layer core configuration
bool "Enable the block layer" if EXPERT
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
bool "Support for large (2TB+) block devices and files"
depends on !64BIT
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
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.
bool "Block layer SG support v4"
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
This option is required by recent UDEV versions to properly
access device serial numbers, etc.
If unsure, say Y.
bool "Block layer SG support v4 helper lib"
Subsystems will normally enable this if needed. Users will not
normally need to manually enable this.
If unsure, say N.
bool "Block layer data integrity support"
select CRC_T10DIF if BLK_DEV_INTEGRITY
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.
bool "Zoned block device support"
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.
bool "Block layer bio throttling support"
depends on BLK_CGROUP=y
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.
bool "Block throttling .low limit interface support (EXPERIMENTAL)"
depends on BLK_DEV_THROTTLING
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.
bool "Block device command line partition parser"
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.
bool "Enable support for block device writeback throttling"
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.
bool "Single queue writeback throttling"
depends on BLK_WBT
Enable writeback throttling by default on legacy single queue devices
bool "Multiqueue writeback throttling"
depends on BLK_WBT
Enable writeback throttling by default on multiqueue devices.
Multiqueue currently doesn't have support for IO scheduling,
enabling this option is recommended.
bool "Block layer debugging information in debugfs"
depends on DEBUG_FS
Include block layer debugging information in debugfs. This information
is mostly useful for kernel developers, but it doesn't incur any cost
Unless you are building a kernel for a tiny system, you should
say Y here.
bool "Logic for interfacing with Opal enabled SEDs"
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"
endif # BLOCK
depends on BLOCK && COMPAT
depends on BLOCK && PCI
depends on BLOCK && VIRTIO