drivers/block/Kconfig - linux-imx - Git at Google


            
            #

            
            # Block device driver configuration

            
            #


            menuconfig BLK_DEV

            
            	bool "Block devices"

            
            	depends on BLOCK

            
            	default y

            
            	---help---

            
            	  Say Y here to get to see options for various different block device

            
            	  drivers. This option alone does not add any kernel code.


            	  If you say N, all options in this submenu will be skipped and disabled;

            
            	  only do this if you know what you are doing.


            if BLK_DEV


            config BLK_DEV_NULL_BLK

            
            	tristate "Null test block driver"

            
            	select CONFIGFS_FS


            config BLK_DEV_FD

            
            	tristate "Normal floppy disk support"

            
            	depends on ARCH_MAY_HAVE_PC_FDC

            
            	---help---

            
            	  If you want to use the floppy disk drive(s) of your PC under Linux,

            
            	  say Y. Information about this driver, especially important for IBM

            
            	  Thinkpad users, is contained in

            
            	  <file:Documentation/blockdev/floppy.txt>.

            
            	  That file also contains the location of the Floppy driver FAQ as

            
            	  well as location of the fdutils package used to configure additional

            
            	  parameters of the driver at run time.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called floppy.


            config AMIGA_FLOPPY

            
            	tristate "Amiga floppy support"

            
            	depends on AMIGA


            config ATARI_FLOPPY

            
            	tristate "Atari floppy support"

            
            	depends on ATARI


            config MAC_FLOPPY

            
            	tristate "Support for PowerMac floppy"

            
            	depends on PPC_PMAC && !PPC_PMAC64

            
            	help

            
            	  If you have a SWIM-3 (Super Woz Integrated Machine 3; from Apple)

            
            	  floppy controller, say Y here. Most commonly found in PowerMacs.


            config BLK_DEV_SWIM

            
            	tristate "Support for SWIM Macintosh floppy"

            
            	depends on M68K && MAC

            
            	help

            
            	  You should select this option if you want floppy support

            
            	  and you don't have a II, IIfx, Q900, Q950 or AV series.


            config AMIGA_Z2RAM

            
            	tristate "Amiga Zorro II ramdisk support"

            
            	depends on ZORRO

            
            	help

            
            	  This enables support for using Chip RAM and Zorro II RAM as a

            
            	  ramdisk or as a swap partition. Say Y if you want to include this

            
            	  driver in the kernel.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called z2ram.


            config GDROM

            
            	tristate "SEGA Dreamcast GD-ROM drive"

            
            	depends on SH_DREAMCAST

            
            	select BLK_SCSI_REQUEST # only for the generic cdrom code

            
            	help

            
            	  A standard SEGA Dreamcast comes with a modified CD ROM drive called a

            
            	  "GD-ROM" by SEGA to signify it is capable of reading special disks

            
            	  with up to 1 GB of data. This drive will also read standard CD ROM

            
            	  disks. Select this option to access any disks in your GD ROM drive.

            
            	  Most users will want to say "Y" here.

            
            	  You can also build this as a module which will be called gdrom.


            config PARIDE

            
            	tristate "Parallel port IDE device support"

            
            	depends on PARPORT_PC

            
            	---help---

            
            	  There are many external CD-ROM and disk devices that connect through

            
            	  your computer's parallel port. Most of them are actually IDE devices

            
            	  using a parallel port IDE adapter. This option enables the PARIDE

            
            	  subsystem which contains drivers for many of these external drives.

            
            	  Read <file:Documentation/blockdev/paride.txt> for more information.


            	  If you have said Y to the "Parallel-port support" configuration

            
            	  option, you may share a single port between your printer and other

            
            	  parallel port devices. Answer Y to build PARIDE support into your

            
            	  kernel, or M if you would like to build it as a loadable module. If

            
            	  your parallel port support is in a loadable module, you must build

            
            	  PARIDE as a module. If you built PARIDE support into your kernel,

            
            	  you may still build the individual protocol modules and high-level

            
            	  drivers as loadable modules. If you build this support as a module,

            
            	  it will be called paride.


            	  To use the PARIDE support, you must say Y or M here and also to at

            
            	  least one high-level driver (e.g. "Parallel port IDE disks",

            
            	  "Parallel port ATAPI CD-ROMs", "Parallel port ATAPI disks" etc.) and

            
            	  to at least one protocol driver (e.g. "ATEN EH-100 protocol",

            
            	  "MicroSolutions backpack protocol", "DataStor Commuter protocol"

            
            	  etc.).


            source "drivers/block/paride/Kconfig"


            source "drivers/block/mtip32xx/Kconfig"


            source "drivers/block/zram/Kconfig"


            config BLK_DEV_DAC960

            
            	tristate "Mylex DAC960/DAC1100 PCI RAID Controller support"

            
            	depends on PCI

            
            	help

            
            	  This driver adds support for the Mylex DAC960, AcceleRAID, and

            
            	  eXtremeRAID PCI RAID controllers.  See the file

            
            	  <file:Documentation/blockdev/README.DAC960> for further information

            
            	  about this driver.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called DAC960.


            config BLK_DEV_UMEM

            
            	tristate "Micro Memory MM5415 Battery Backed RAM support"

            
            	depends on PCI

            
            	---help---

            
            	  Saying Y here will include support for the MM5415 family of

            
            	  battery backed (Non-volatile) RAM cards.

            
            	  <http://www.umem.com/>


            	  The cards appear as block devices that can be partitioned into

            
            	  as many as 15 partitions.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called umem.


            	  The umem driver has not yet been allocated a MAJOR number, so

            
            	  one is chosen dynamically.


            config BLK_DEV_UBD

            
            	bool "Virtual block device"

            
            	depends on UML

            
            	---help---

            
                      The User-Mode Linux port includes a driver called UBD which will let

            
                      you access arbitrary files on the host computer as block devices.

            
                      Unless you know that you do not need such virtual block devices say

            
                      Y here.


            config BLK_DEV_UBD_SYNC

            
            	bool "Always do synchronous disk IO for UBD"

            
            	depends on BLK_DEV_UBD

            
            	---help---

            
            	  Writes to the virtual block device are not immediately written to the

            
            	  host's disk; this may cause problems if, for example, the User-Mode

            
            	  Linux 'Virtual Machine' uses a journalling filesystem and the host

            
            	  computer crashes.


                      Synchronous operation (i.e. always writing data to the host's disk

            
                      immediately) is configurable on a per-UBD basis by using a special

            
                      kernel command line option.  Alternatively, you can say Y here to

            
                      turn on synchronous operation by default for all block devices.


                      If you're running a journalling file system (like reiserfs, for

            
                      example) in your virtual machine, you will want to say Y here.  If

            
                      you care for the safety of the data in your virtual machine, Y is a

            
                      wise choice too.  In all other cases (for example, if you're just

            
                      playing around with User-Mode Linux) you can choose N.


            config BLK_DEV_COW_COMMON

            
            	bool

            
            	default BLK_DEV_UBD


            config BLK_DEV_LOOP

            
            	tristate "Loopback device support"

            
            	---help---

            
            	  Saying Y here will allow you to use a regular file as a block

            
            	  device; you can then create a file system on that block device and

            
            	  mount it just as you would mount other block devices such as hard

            
            	  drive partitions, CD-ROM drives or floppy drives. The loop devices

            
            	  are block special device files with major number 7 and typically

            
            	  called /dev/loop0, /dev/loop1 etc.


            	  This is useful if you want to check an ISO 9660 file system before

            
            	  burning the CD, or if you want to use floppy images without first

            
            	  writing them to floppy. Furthermore, some Linux distributions avoid

            
            	  the need for a dedicated Linux partition by keeping their complete

            
            	  root file system inside a DOS FAT file using this loop device

            
            	  driver.


            	  To use the loop device, you need the losetup utility, found in the

            
            	  util-linux package, see

            
            	  <https://www.kernel.org/pub/linux/utils/util-linux/>.


            	  The loop device driver can also be used to "hide" a file system in

            
            	  a disk partition, floppy, or regular file, either using encryption

            
            	  (scrambling the data) or steganography (hiding the data in the low

            
            	  bits of, say, a sound file). This is also safe if the file resides

            
            	  on a remote file server.


            	  There are several ways of encrypting disks. Some of these require

            
            	  kernel patches. The vanilla kernel offers the cryptoloop option

            
            	  and a Device Mapper target (which is superior, as it supports all

            
            	  file systems). If you want to use the cryptoloop, say Y to both

            
            	  LOOP and CRYPTOLOOP, and make sure you have a recent (version 2.12

            
            	  or later) version of util-linux. Additionally, be aware that

            
            	  the cryptoloop is not safe for storing journaled filesystems.


            	  Note that this loop device has nothing to do with the loopback

            
            	  device used for network connections from the machine to itself.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called loop.


            	  Most users will answer N here.


            config BLK_DEV_LOOP_MIN_COUNT

            
            	int "Number of loop devices to pre-create at init time"

            
            	depends on BLK_DEV_LOOP

            
            	default 8

            
            	help

            
            	  Static number of loop devices to be unconditionally pre-created

            
            	  at init time.


            	  This default value can be overwritten on the kernel command

            
            	  line or with module-parameter loop.max_loop.


            	  The historic default is 8. If a late 2011 version of losetup(8)

            
            	  is used, it can be set to 0, since needed loop devices can be

            
            	  dynamically allocated with the /dev/loop-control interface.


            config BLK_DEV_CRYPTOLOOP

            
            	tristate "Cryptoloop Support"

            
            	select CRYPTO

            
            	select CRYPTO_CBC

            
            	depends on BLK_DEV_LOOP

            
            	---help---

            
            	  Say Y here if you want to be able to use the ciphers that are

            
            	  provided by the CryptoAPI as loop transformation. This might be

            
            	  used as hard disk encryption.


            	  WARNING: This device is not safe for journaled file systems like

            
            	  ext3 or Reiserfs. Please use the Device Mapper crypto module

            
            	  instead, which can be configured to be on-disk compatible with the

            
            	  cryptoloop device.


            source "drivers/block/drbd/Kconfig"


            config BLK_DEV_NBD

            
            	tristate "Network block device support"

            
            	depends on NET

            
            	---help---

            
            	  Saying Y here will allow your computer to be a client for network

            
            	  block devices, i.e. it will be able to use block devices exported by

            
            	  servers (mount file systems on them etc.). Communication between

            
            	  client and server works over TCP/IP networking, but to the client

            
            	  program this is hidden: it looks like a regular local file access to

            
            	  a block device special file such as /dev/nd0.


            	  Network block devices also allows you to run a block-device in

            
            	  userland (making server and client physically the same computer,

            
            	  communicating using the loopback network device).


            	  Read <file:Documentation/blockdev/nbd.txt> for more information,

            
            	  especially about where to find the server code, which runs in user

            
            	  space and does not need special kernel support.


            	  Note that this has nothing to do with the network file systems NFS

            
            	  or Coda; you can say N here even if you intend to use NFS or Coda.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called nbd.


            	  If unsure, say N.


            config BLK_DEV_SKD

            
            	tristate "STEC S1120 Block Driver"

            
            	depends on PCI

            
            	depends on 64BIT

            
            	---help---

            
            	Saying Y or M here will enable support for the

            
            	STEC, Inc. S1120 PCIe SSD.


            	Use device /dev/skd$N amd /dev/skd$Np$M.


            config BLK_DEV_SX8

            
            	tristate "Promise SATA SX8 support"

            
            	depends on PCI

            
            	---help---

            
            	  Saying Y or M here will enable support for the

            
            	  Promise SATA SX8 controllers.


            	  Use devices /dev/sx8/$N and /dev/sx8/$Np$M.


            config BLK_DEV_RAM

            
            	tristate "RAM block device support"

            
            	select DAX if BLK_DEV_RAM_DAX

            
            	---help---

            
            	  Saying Y here will allow you to use a portion of your RAM memory as

            
            	  a block device, so that you can make file systems on it, read and

            
            	  write to it and do all the other things that you can do with normal

            
            	  block devices (such as hard drives). It is usually used to load and

            
            	  store a copy of a minimal root file system off of a floppy into RAM

            
            	  during the initial install of Linux.


            	  Note that the kernel command line option "ramdisk=XX" is now obsolete.

            
            	  For details, read <file:Documentation/blockdev/ramdisk.txt>.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called brd. An alias "rd" has been defined

            
            	  for historical reasons.


            	  Most normal users won't need the RAM disk functionality, and can

            
            	  thus say N here.


            config BLK_DEV_RAM_COUNT

            
            	int "Default number of RAM disks"

            
            	default "16"

            
            	depends on BLK_DEV_RAM

            
            	help

            
            	  The default value is 16 RAM disks. Change this if you know what you

            
            	  are doing. If you boot from a filesystem that needs to be extracted

            
            	  in memory, you will need at least one RAM disk (e.g. root on cramfs).


            config BLK_DEV_RAM_SIZE

            
            	int "Default RAM disk size (kbytes)"

            
            	depends on BLK_DEV_RAM

            
            	default "4096"

            
            	help

            
            	  The default value is 4096 kilobytes. Only change this if you know

            
            	  what you are doing.


            config BLK_DEV_RAM_DAX

            
            	bool "Support Direct Access (DAX) to RAM block devices"

            
            	depends on BLK_DEV_RAM && FS_DAX

            
            	default n

            
            	help

            
            	  Support filesystems using DAX to access RAM block devices.  This

            
            	  avoids double-buffering data in the page cache before copying it

            
            	  to the block device.  Answering Y will slightly enlarge the kernel,

            
            	  and will prevent RAM block device backing store memory from being

            
            	  allocated from highmem (only a problem for highmem systems).


            config CDROM_PKTCDVD

            
            	tristate "Packet writing on CD/DVD media (DEPRECATED)"

            
            	depends on !UML

            
            	select BLK_SCSI_REQUEST

            
            	help

            
            	  Note: This driver is deprecated and will be removed from the

            
            	  kernel in the near future!


            	  If you have a CDROM/DVD drive that supports packet writing, say

            
            	  Y to include support. It should work with any MMC/Mt Fuji

            
            	  compliant ATAPI or SCSI drive, which is just about any newer

            
            	  DVD/CD writer.


            	  Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs

            
            	  is possible.

            
            	  DVD-RW disks must be in restricted overwrite mode.


            	  See the file <file:Documentation/cdrom/packet-writing.txt>

            
            	  for further information on the use of this driver.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called pktcdvd.


            config CDROM_PKTCDVD_BUFFERS

            
            	int "Free buffers for data gathering"

            
            	depends on CDROM_PKTCDVD

            
            	default "8"

            
            	help

            
            	  This controls the maximum number of active concurrent packets. More

            
            	  concurrent packets can increase write performance, but also require

            
            	  more memory. Each concurrent packet will require approximately 64Kb

            
            	  of non-swappable kernel memory, memory which will be allocated when

            
            	  a disc is opened for writing.


            config CDROM_PKTCDVD_WCACHE

            
            	bool "Enable write caching"

            
            	depends on CDROM_PKTCDVD

            
            	help

            
            	  If enabled, write caching will be set for the CD-R/W device. For now

            
            	  this option is dangerous unless the CD-RW media is known good, as we

            
            	  don't do deferred write error handling yet.


            config ATA_OVER_ETH

            
            	tristate "ATA over Ethernet support"

            
            	depends on NET

            
            	help

            
            	This driver provides Support for ATA over Ethernet block

            
            	devices like the Coraid EtherDrive (R) Storage Blade.


            config SUNVDC

            
            	tristate "Sun Virtual Disk Client support"

            
            	depends on SUN_LDOMS

            
            	help

            
            	  Support for virtual disk devices as a client under Sun

            
            	  Logical Domains.


            source "drivers/s390/block/Kconfig"


            config XILINX_SYSACE

            
            	tristate "Xilinx SystemACE support"

            
            	depends on 4xx || MICROBLAZE

            
            	help

            
            	  Include support for the Xilinx SystemACE CompactFlash interface


            config XEN_BLKDEV_FRONTEND

            
            	tristate "Xen virtual block device support"

            
            	depends on XEN

            
            	default y

            
            	select XEN_XENBUS_FRONTEND

            
            	help

            
            	  This driver implements the front-end of the Xen virtual

            
            	  block device driver.  It communicates with a back-end driver

            
            	  in another domain which drives the actual block device.


            config XEN_BLKDEV_BACKEND

            
            	tristate "Xen block-device backend driver"

            
            	depends on XEN_BACKEND

            
            	help

            
            	  The block-device backend driver allows the kernel to export its

            
            	  block devices to other guests via a high-performance shared-memory

            
            	  interface.


            	  The corresponding Linux frontend driver is enabled by the

            
            	  CONFIG_XEN_BLKDEV_FRONTEND configuration option.


            	  The backend driver attaches itself to a any block device specified

            
            	  in the XenBus configuration. There are no limits to what the block

            
            	  device as long as it has a major and minor.


            	  If you are compiling a kernel to run in a Xen block backend driver

            
            	  domain (often this is domain 0) you should say Y here. To

            
            	  compile this driver as a module, chose M here: the module

            
            	  will be called xen-blkback.


            config VIRTIO_BLK

            
            	tristate "Virtio block driver"

            
            	depends on VIRTIO

            
            	---help---

            
            	  This is the virtual block driver for virtio.  It can be used with

            
                      QEMU based VMMs (like KVM or Xen).  Say Y or M.


            config VIRTIO_BLK_SCSI

            
            	bool "SCSI passthrough request for the Virtio block driver"

            
            	depends on VIRTIO_BLK

            
            	select BLK_SCSI_REQUEST

            
            	---help---

            
            	  Enable support for SCSI passthrough (e.g. the SG_IO ioctl) on

            
            	  virtio-blk devices.  This is only supported for the legacy

            
            	  virtio protocol and not enabled by default by any hypervisor.

            
            	  You probably want to use virtio-scsi instead.


            config BLK_DEV_RBD

            
            	tristate "Rados block device (RBD)"

            
            	depends on INET && BLOCK

            
            	select CEPH_LIB

            
            	select LIBCRC32C

            
            	select CRYPTO_AES

            
            	select CRYPTO

            
            	default n

            
            	help

            
            	  Say Y here if you want include the Rados block device, which stripes

            
            	  a block device over objects stored in the Ceph distributed object

            
            	  store.


            	  More information at http://ceph.newdream.net/.


            	  If unsure, say N.


            config BLK_DEV_RSXX

            
            	tristate "IBM Flash Adapter 900GB Full Height PCIe Device Driver"

            
            	depends on PCI

            
            	help

            
            	  Device driver for IBM's high speed PCIe SSD

            
            	  storage device: Flash Adapter 900GB Full Height.


            	  To compile this driver as a module, choose M here: the

            
            	  module will be called rsxx.


            endif # BLK_DEV
	#
	# Block device driver configuration
	#

	menuconfig BLK_DEV
	bool "Block devices"
	depends on BLOCK
	default y
	---help---
	Say Y here to get to see options for various different block device
	drivers. This option alone does not add any kernel code.

	If you say N, all options in this submenu will be skipped and disabled;
	only do this if you know what you are doing.

	if BLK_DEV

	config BLK_DEV_NULL_BLK
	tristate "Null test block driver"
	select CONFIGFS_FS

	config BLK_DEV_FD
	tristate "Normal floppy disk support"
	depends on ARCH_MAY_HAVE_PC_FDC
	---help---
	If you want to use the floppy disk drive(s) of your PC under Linux,
	say Y. Information about this driver, especially important for IBM
	Thinkpad users, is contained in
	<file:Documentation/blockdev/floppy.txt>.
	That file also contains the location of the Floppy driver FAQ as
	well as location of the fdutils package used to configure additional
	parameters of the driver at run time.

	To compile this driver as a module, choose M here: the
	module will be called floppy.

	config AMIGA_FLOPPY
	tristate "Amiga floppy support"
	depends on AMIGA

	config ATARI_FLOPPY
	tristate "Atari floppy support"
	depends on ATARI

	config MAC_FLOPPY
	tristate "Support for PowerMac floppy"
	depends on PPC_PMAC && !PPC_PMAC64
	help
	If you have a SWIM-3 (Super Woz Integrated Machine 3; from Apple)
	floppy controller, say Y here. Most commonly found in PowerMacs.

	config BLK_DEV_SWIM
	tristate "Support for SWIM Macintosh floppy"
	depends on M68K && MAC
	help
	You should select this option if you want floppy support
	and you don't have a II, IIfx, Q900, Q950 or AV series.

	config AMIGA_Z2RAM
	tristate "Amiga Zorro II ramdisk support"
	depends on ZORRO
	help
	This enables support for using Chip RAM and Zorro II RAM as a
	ramdisk or as a swap partition. Say Y if you want to include this
	driver in the kernel.

	To compile this driver as a module, choose M here: the
	module will be called z2ram.

	config GDROM
	tristate "SEGA Dreamcast GD-ROM drive"
	depends on SH_DREAMCAST
	select BLK_SCSI_REQUEST # only for the generic cdrom code
	help
	A standard SEGA Dreamcast comes with a modified CD ROM drive called a
	"GD-ROM" by SEGA to signify it is capable of reading special disks
	with up to 1 GB of data. This drive will also read standard CD ROM
	disks. Select this option to access any disks in your GD ROM drive.
	Most users will want to say "Y" here.
	You can also build this as a module which will be called gdrom.

	config PARIDE
	tristate "Parallel port IDE device support"
	depends on PARPORT_PC
	---help---
	There are many external CD-ROM and disk devices that connect through
	your computer's parallel port. Most of them are actually IDE devices
	using a parallel port IDE adapter. This option enables the PARIDE
	subsystem which contains drivers for many of these external drives.
	Read <file:Documentation/blockdev/paride.txt> for more information.

	If you have said Y to the "Parallel-port support" configuration
	option, you may share a single port between your printer and other
	parallel port devices. Answer Y to build PARIDE support into your
	kernel, or M if you would like to build it as a loadable module. If
	your parallel port support is in a loadable module, you must build
	PARIDE as a module. If you built PARIDE support into your kernel,
	you may still build the individual protocol modules and high-level
	drivers as loadable modules. If you build this support as a module,
	it will be called paride.

	To use the PARIDE support, you must say Y or M here and also to at
	least one high-level driver (e.g. "Parallel port IDE disks",
	"Parallel port ATAPI CD-ROMs", "Parallel port ATAPI disks" etc.) and
	to at least one protocol driver (e.g. "ATEN EH-100 protocol",
	"MicroSolutions backpack protocol", "DataStor Commuter protocol"
	etc.).

	source "drivers/block/paride/Kconfig"

	source "drivers/block/mtip32xx/Kconfig"

	source "drivers/block/zram/Kconfig"

	config BLK_DEV_DAC960
	tristate "Mylex DAC960/DAC1100 PCI RAID Controller support"
	depends on PCI
	help
	This driver adds support for the Mylex DAC960, AcceleRAID, and
	eXtremeRAID PCI RAID controllers. See the file
	<file:Documentation/blockdev/README.DAC960> for further information
	about this driver.

	To compile this driver as a module, choose M here: the
	module will be called DAC960.

	config BLK_DEV_UMEM
	tristate "Micro Memory MM5415 Battery Backed RAM support"
	depends on PCI
	---help---
	Saying Y here will include support for the MM5415 family of
	battery backed (Non-volatile) RAM cards.
	<http://www.umem.com/>

	The cards appear as block devices that can be partitioned into
	as many as 15 partitions.

	To compile this driver as a module, choose M here: the
	module will be called umem.

	The umem driver has not yet been allocated a MAJOR number, so
	one is chosen dynamically.

	config BLK_DEV_UBD
	bool "Virtual block device"
	depends on UML
	---help---
	The User-Mode Linux port includes a driver called UBD which will let
	you access arbitrary files on the host computer as block devices.
	Unless you know that you do not need such virtual block devices say
	Y here.

	config BLK_DEV_UBD_SYNC
	bool "Always do synchronous disk IO for UBD"
	depends on BLK_DEV_UBD
	---help---
	Writes to the virtual block device are not immediately written to the
	host's disk; this may cause problems if, for example, the User-Mode
	Linux 'Virtual Machine' uses a journalling filesystem and the host
	computer crashes.

	Synchronous operation (i.e. always writing data to the host's disk
	immediately) is configurable on a per-UBD basis by using a special
	kernel command line option. Alternatively, you can say Y here to
	turn on synchronous operation by default for all block devices.

	If you're running a journalling file system (like reiserfs, for
	example) in your virtual machine, you will want to say Y here. If
	you care for the safety of the data in your virtual machine, Y is a
	wise choice too. In all other cases (for example, if you're just
	playing around with User-Mode Linux) you can choose N.

	config BLK_DEV_COW_COMMON
	bool
	default BLK_DEV_UBD

	config BLK_DEV_LOOP
	tristate "Loopback device support"
	---help---
	Saying Y here will allow you to use a regular file as a block
	device; you can then create a file system on that block device and
	mount it just as you would mount other block devices such as hard
	drive partitions, CD-ROM drives or floppy drives. The loop devices
	are block special device files with major number 7 and typically
	called /dev/loop0, /dev/loop1 etc.

	This is useful if you want to check an ISO 9660 file system before
	burning the CD, or if you want to use floppy images without first
	writing them to floppy. Furthermore, some Linux distributions avoid
	the need for a dedicated Linux partition by keeping their complete
	root file system inside a DOS FAT file using this loop device
	driver.

	To use the loop device, you need the losetup utility, found in the
	util-linux package, see
	<https://www.kernel.org/pub/linux/utils/util-linux/>.

	The loop device driver can also be used to "hide" a file system in
	a disk partition, floppy, or regular file, either using encryption
	(scrambling the data) or steganography (hiding the data in the low
	bits of, say, a sound file). This is also safe if the file resides
	on a remote file server.

	There are several ways of encrypting disks. Some of these require
	kernel patches. The vanilla kernel offers the cryptoloop option
	and a Device Mapper target (which is superior, as it supports all
	file systems). If you want to use the cryptoloop, say Y to both
	LOOP and CRYPTOLOOP, and make sure you have a recent (version 2.12
	or later) version of util-linux. Additionally, be aware that
	the cryptoloop is not safe for storing journaled filesystems.

	Note that this loop device has nothing to do with the loopback
	device used for network connections from the machine to itself.

	To compile this driver as a module, choose M here: the
	module will be called loop.

	Most users will answer N here.

	config BLK_DEV_LOOP_MIN_COUNT
	int "Number of loop devices to pre-create at init time"
	depends on BLK_DEV_LOOP
	default 8
	help
	Static number of loop devices to be unconditionally pre-created
	at init time.

	This default value can be overwritten on the kernel command
	line or with module-parameter loop.max_loop.

	The historic default is 8. If a late 2011 version of losetup(8)
	is used, it can be set to 0, since needed loop devices can be
	dynamically allocated with the /dev/loop-control interface.

	config BLK_DEV_CRYPTOLOOP
	tristate "Cryptoloop Support"
	select CRYPTO
	select CRYPTO_CBC
	depends on BLK_DEV_LOOP
	---help---
	Say Y here if you want to be able to use the ciphers that are
	provided by the CryptoAPI as loop transformation. This might be
	used as hard disk encryption.

	WARNING: This device is not safe for journaled file systems like
	ext3 or Reiserfs. Please use the Device Mapper crypto module
	instead, which can be configured to be on-disk compatible with the
	cryptoloop device.

	source "drivers/block/drbd/Kconfig"

	config BLK_DEV_NBD
	tristate "Network block device support"
	depends on NET
	---help---
	Saying Y here will allow your computer to be a client for network
	block devices, i.e. it will be able to use block devices exported by
	servers (mount file systems on them etc.). Communication between
	client and server works over TCP/IP networking, but to the client
	program this is hidden: it looks like a regular local file access to
	a block device special file such as /dev/nd0.

	Network block devices also allows you to run a block-device in
	userland (making server and client physically the same computer,
	communicating using the loopback network device).

	Read <file:Documentation/blockdev/nbd.txt> for more information,
	especially about where to find the server code, which runs in user
	space and does not need special kernel support.

	Note that this has nothing to do with the network file systems NFS
	or Coda; you can say N here even if you intend to use NFS or Coda.

	To compile this driver as a module, choose M here: the
	module will be called nbd.

	If unsure, say N.

	config BLK_DEV_SKD
	tristate "STEC S1120 Block Driver"
	depends on PCI
	depends on 64BIT
	---help---
	Saying Y or M here will enable support for the
	STEC, Inc. S1120 PCIe SSD.

	Use device /dev/skd$N amd /dev/skd$Np$M.

	config BLK_DEV_SX8
	tristate "Promise SATA SX8 support"
	depends on PCI
	---help---
	Saying Y or M here will enable support for the
	Promise SATA SX8 controllers.

	Use devices /dev/sx8/$N and /dev/sx8/$Np$M.

	config BLK_DEV_RAM
	tristate "RAM block device support"
	select DAX if BLK_DEV_RAM_DAX
	---help---
	Saying Y here will allow you to use a portion of your RAM memory as
	a block device, so that you can make file systems on it, read and
	write to it and do all the other things that you can do with normal
	block devices (such as hard drives). It is usually used to load and
	store a copy of a minimal root file system off of a floppy into RAM
	during the initial install of Linux.

	Note that the kernel command line option "ramdisk=XX" is now obsolete.
	For details, read <file:Documentation/blockdev/ramdisk.txt>.

	To compile this driver as a module, choose M here: the
	module will be called brd. An alias "rd" has been defined
	for historical reasons.

	Most normal users won't need the RAM disk functionality, and can
	thus say N here.

	config BLK_DEV_RAM_COUNT
	int "Default number of RAM disks"
	default "16"
	depends on BLK_DEV_RAM
	help
	The default value is 16 RAM disks. Change this if you know what you
	are doing. If you boot from a filesystem that needs to be extracted
	in memory, you will need at least one RAM disk (e.g. root on cramfs).

	config BLK_DEV_RAM_SIZE
	int "Default RAM disk size (kbytes)"
	depends on BLK_DEV_RAM
	default "4096"
	help
	The default value is 4096 kilobytes. Only change this if you know
	what you are doing.

	config BLK_DEV_RAM_DAX
	bool "Support Direct Access (DAX) to RAM block devices"
	depends on BLK_DEV_RAM && FS_DAX
	default n
	help
	Support filesystems using DAX to access RAM block devices. This
	avoids double-buffering data in the page cache before copying it
	to the block device. Answering Y will slightly enlarge the kernel,
	and will prevent RAM block device backing store memory from being
	allocated from highmem (only a problem for highmem systems).

	config CDROM_PKTCDVD
	tristate "Packet writing on CD/DVD media (DEPRECATED)"
	depends on !UML
	select BLK_SCSI_REQUEST
	help
	Note: This driver is deprecated and will be removed from the
	kernel in the near future!

	If you have a CDROM/DVD drive that supports packet writing, say
	Y to include support. It should work with any MMC/Mt Fuji
	compliant ATAPI or SCSI drive, which is just about any newer
	DVD/CD writer.

	Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs
	is possible.
	DVD-RW disks must be in restricted overwrite mode.

	See the file <file:Documentation/cdrom/packet-writing.txt>
	for further information on the use of this driver.

	To compile this driver as a module, choose M here: the
	module will be called pktcdvd.

	config CDROM_PKTCDVD_BUFFERS
	int "Free buffers for data gathering"
	depends on CDROM_PKTCDVD
	default "8"
	help
	This controls the maximum number of active concurrent packets. More
	concurrent packets can increase write performance, but also require
	more memory. Each concurrent packet will require approximately 64Kb
	of non-swappable kernel memory, memory which will be allocated when
	a disc is opened for writing.

	config CDROM_PKTCDVD_WCACHE
	bool "Enable write caching"
	depends on CDROM_PKTCDVD
	help
	If enabled, write caching will be set for the CD-R/W device. For now
	this option is dangerous unless the CD-RW media is known good, as we
	don't do deferred write error handling yet.

	config ATA_OVER_ETH
	tristate "ATA over Ethernet support"
	depends on NET
	help
	This driver provides Support for ATA over Ethernet block
	devices like the Coraid EtherDrive (R) Storage Blade.

	config SUNVDC
	tristate "Sun Virtual Disk Client support"
	depends on SUN_LDOMS
	help
	Support for virtual disk devices as a client under Sun
	Logical Domains.

	source "drivers/s390/block/Kconfig"

	config XILINX_SYSACE
	tristate "Xilinx SystemACE support"
	depends on 4xx \|\| MICROBLAZE
	help
	Include support for the Xilinx SystemACE CompactFlash interface

	config XEN_BLKDEV_FRONTEND
	tristate "Xen virtual block device support"
	depends on XEN
	default y
	select XEN_XENBUS_FRONTEND
	help
	This driver implements the front-end of the Xen virtual
	block device driver. It communicates with a back-end driver
	in another domain which drives the actual block device.

	config XEN_BLKDEV_BACKEND
	tristate "Xen block-device backend driver"
	depends on XEN_BACKEND
	help
	The block-device backend driver allows the kernel to export its
	block devices to other guests via a high-performance shared-memory
	interface.

	The corresponding Linux frontend driver is enabled by the
	CONFIG_XEN_BLKDEV_FRONTEND configuration option.

	The backend driver attaches itself to a any block device specified
	in the XenBus configuration. There are no limits to what the block
	device as long as it has a major and minor.

	If you are compiling a kernel to run in a Xen block backend driver
	domain (often this is domain 0) you should say Y here. To
	compile this driver as a module, chose M here: the module
	will be called xen-blkback.


	config VIRTIO_BLK
	tristate "Virtio block driver"
	depends on VIRTIO
	---help---
	This is the virtual block driver for virtio. It can be used with
	QEMU based VMMs (like KVM or Xen). Say Y or M.

	config VIRTIO_BLK_SCSI
	bool "SCSI passthrough request for the Virtio block driver"
	depends on VIRTIO_BLK
	select BLK_SCSI_REQUEST
	---help---
	Enable support for SCSI passthrough (e.g. the SG_IO ioctl) on
	virtio-blk devices. This is only supported for the legacy
	virtio protocol and not enabled by default by any hypervisor.
	You probably want to use virtio-scsi instead.

	config BLK_DEV_RBD
	tristate "Rados block device (RBD)"
	depends on INET && BLOCK
	select CEPH_LIB
	select LIBCRC32C
	select CRYPTO_AES
	select CRYPTO
	default n
	help
	Say Y here if you want include the Rados block device, which stripes
	a block device over objects stored in the Ceph distributed object
	store.

	More information at http://ceph.newdream.net/.

	If unsure, say N.

	config BLK_DEV_RSXX
	tristate "IBM Flash Adapter 900GB Full Height PCIe Device Driver"
	depends on PCI
	help
	Device driver for IBM's high speed PCIe SSD
	storage device: Flash Adapter 900GB Full Height.

	To compile this driver as a module, choose M here: the
	module will be called rsxx.

	endif # BLK_DEV