[linux-block.git] / drivers / block / Kconfig

# SPDX-License-Identifier: GPL-2.0
#
# 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

source "drivers/block/null_blk/Kconfig"

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/admin-guide/blockdev/floppy.rst>.
	  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 BLK_DEV_FD_RAWCMD
	bool "Support for raw floppy disk commands (DEPRECATED)"
	depends on BLK_DEV_FD
	help
	  If you want to use actual physical floppies and expect to do
	  special low-level hardware accesses to them (access and use
	  non-standard formats, for example), then enable this.

	  Note that the code enabled by this option is rarely used and
	  might be unstable or insecure, and distros should not enable it.

	  Note: FDRAWCMD is deprecated and will be removed from the kernel
	  in the near future.

	  If unsure, say N.

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 && !HIGHMEM
	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 N64CART
	bool "N64 cart support"
	depends on MACH_NINTENDO64
	help
	  Support for the N64 cart.

config CDROM
	tristate

config GDROM
	tristate "SEGA Dreamcast GD-ROM drive"
	depends on SH_DREAMCAST
	select CDROM
	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/admin-guide/blockdev/paride.rst> 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_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.

	  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.

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/admin-guide/blockdev/nbd.rst> 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_RAM
	tristate "RAM block device support"
	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/admin-guide/blockdev/ramdisk.rst>.

	  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 CDROM_PKTCDVD
	tristate "Packet writing on CD/DVD media (DEPRECATED)"
	depends on !UML
	depends on SCSI
	select CDROM
	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.rst>
	  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 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
	select SG_POOL
	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 BLK_DEV_RBD
	tristate "Rados block device (RBD)"
	depends on INET && BLOCK
	select CEPH_LIB
	select LIBCRC32C
	select CRYPTO_AES
	select CRYPTO
	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_UBLK
	tristate "Userspace block driver (Experimental)"
	select IO_URING
	help
	  io_uring based userspace block driver. Together with ublk server, ublk
	  has been working well, but interface with userspace or command data
	  definition isn't finalized yet, and might change according to future
	  requirement, so mark is as experimental now.

	  Say Y if you want to get better performance because task_work_add()
	  can be used in IO path for replacing io_uring cmd, which will become
	  shared between IO tasks and ubq daemon, meantime task_work_add() can
	  can handle batch more effectively, but task_work_add() isn't exported
	  for module, so ublk has to be built to kernel.

source "drivers/block/rnbd/Kconfig"

endif # BLK_DEV
Commit	Line	Data
b2441318	1	# SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	#
	3	# Block device driver configuration
	4	#
	5
fd11d171 JE	6	menuconfig BLK_DEV
	7	bool "Block devices"
	8	depends on BLOCK
	9	default y
a7f7f624	10	help
06bfb7eb JE	11	Say Y here to get to see options for various different block device
	12	drivers. This option alone does not add any kernel code.
	13
	14	If you say N, all options in this submenu will be skipped and disabled;
	15	only do this if you know what you are doing.
9361401e	16
fd11d171	17	if BLK_DEV
1da177e4	18
eebf34a8	19	source "drivers/block/null_blk/Kconfig"
f2298c04	20
1da177e4 LT	21	config BLK_DEV_FD
1da177e4 LT	22	tristate "Normal floppy disk support"
a08b6b79	23	depends on ARCH_MAY_HAVE_PC_FDC
a7f7f624	24	help
1da177e4 LT	25	If you want to use the floppy disk drive(s) of your PC under Linux,
1da177e4 LT	26	say Y. Information about this driver, especially important for IBM
31c00fc1	27	Thinkpad users, is contained in
e7751617	28	<file:Documentation/admin-guide/blockdev/floppy.rst>.
1da177e4 LT	29	That file also contains the location of the Floppy driver FAQ as
	30	well as location of the fdutils package used to configure additional
	31	parameters of the driver at run time.
	32
	33	To compile this driver as a module, choose M here: the
	34	module will be called floppy.
	35
233087ca WT	36	config BLK_DEV_FD_RAWCMD
	37	bool "Support for raw floppy disk commands (DEPRECATED)"
	38	depends on BLK_DEV_FD
	39	help
	40	If you want to use actual physical floppies and expect to do
	41	special low-level hardware accesses to them (access and use
	42	non-standard formats, for example), then enable this.
	43
	44	Note that the code enabled by this option is rarely used and
	45	might be unstable or insecure, and distros should not enable it.
	46
	47	Note: FDRAWCMD is deprecated and will be removed from the kernel
	48	in the near future.
	49
	50	If unsure, say N.
	51
1da177e4 LT	52	config AMIGA_FLOPPY
	53	tristate "Amiga floppy support"
	54	depends on AMIGA
	55
	56	config ATARI_FLOPPY
	57	tristate "Atari floppy support"
	58	depends on ATARI
	59
1da177e4 LT	60	config MAC_FLOPPY
	61	tristate "Support for PowerMac floppy"
	62	depends on PPC_PMAC && !PPC_PMAC64
	63	help
	64	If you have a SWIM-3 (Super Woz Integrated Machine 3; from Apple)
	65	floppy controller, say Y here. Most commonly found in PowerMacs.
	66
8852ecd9 LV	67	config BLK_DEV_SWIM
8852ecd9 LV	68	tristate "Support for SWIM Macintosh floppy"
4c6e5bc8	69	depends on M68K && MAC && !HIGHMEM
8852ecd9 LV	70	help
	71	You should select this option if you want floppy support
	72	and you don't have a II, IIfx, Q900, Q950 or AV series.
	73
1da177e4 LT	74	config AMIGA_Z2RAM
	75	tristate "Amiga Zorro II ramdisk support"
	76	depends on ZORRO
	77	help
	78	This enables support for using Chip RAM and Zorro II RAM as a
	79	ramdisk or as a swap partition. Say Y if you want to include this
	80	driver in the kernel.
	81
	82	To compile this driver as a module, choose M here: the
	83	module will be called z2ram.
	84
d9b2a2bb LK	85	config N64CART
	86	bool "N64 cart support"
	87	depends on MACH_NINTENDO64
	88	help
	89	Support for the N64 cart.
	90
2a750166	91	config CDROM
a116895f	92	tristate
2a750166	93
2395e463 RD	94	config GDROM
	95	tristate "SEGA Dreamcast GD-ROM drive"
	96	depends on SH_DREAMCAST
2a750166	97	select CDROM
2395e463 RD	98	help
	99	A standard SEGA Dreamcast comes with a modified CD ROM drive called a
	100	"GD-ROM" by SEGA to signify it is capable of reading special disks
	101	with up to 1 GB of data. This drive will also read standard CD ROM
	102	disks. Select this option to access any disks in your GD ROM drive.
	103	Most users will want to say "Y" here.
	104	You can also build this as a module which will be called gdrom.
	105
1da177e4 LT	106	config PARIDE
1da177e4 LT	107	tristate "Parallel port IDE device support"
6a19b41b	108	depends on PARPORT_PC
a7f7f624	109	help
1da177e4 LT	110	There are many external CD-ROM and disk devices that connect through
	111	your computer's parallel port. Most of them are actually IDE devices
	112	using a parallel port IDE adapter. This option enables the PARIDE
	113	subsystem which contains drivers for many of these external drives.
e7751617	114	Read <file:Documentation/admin-guide/blockdev/paride.rst> for more information.
1da177e4 LT	115
	116	If you have said Y to the "Parallel-port support" configuration
	117	option, you may share a single port between your printer and other
	118	parallel port devices. Answer Y to build PARIDE support into your
	119	kernel, or M if you would like to build it as a loadable module. If
	120	your parallel port support is in a loadable module, you must build
	121	PARIDE as a module. If you built PARIDE support into your kernel,
	122	you may still build the individual protocol modules and high-level
	123	drivers as loadable modules. If you build this support as a module,
	124	it will be called paride.
	125
	126	To use the PARIDE support, you must say Y or M here and also to at
	127	least one high-level driver (e.g. "Parallel port IDE disks",
	128	"Parallel port ATAPI CD-ROMs", "Parallel port ATAPI disks" etc.) and
	129	to at least one protocol driver (e.g. "ATEN EH-100 protocol",
	130	"MicroSolutions backpack protocol", "DataStor Commuter protocol"
	131	etc.).
	132
	133	source "drivers/block/paride/Kconfig"
	134
88523a61 SB	135	source "drivers/block/mtip32xx/Kconfig"
88523a61 SB	136
cd67e10a MK	137	source "drivers/block/zram/Kconfig"
cd67e10a MK	138
1da177e4 LT	139	config BLK_DEV_UBD
	140	bool "Virtual block device"
	141	depends on UML
a7f7f624	142	help
1da177e4 LT	143	The User-Mode Linux port includes a driver called UBD which will let
	144	you access arbitrary files on the host computer as block devices.
	145	Unless you know that you do not need such virtual block devices say
	146	Y here.
	147
	148	config BLK_DEV_UBD_SYNC
	149	bool "Always do synchronous disk IO for UBD"
	150	depends on BLK_DEV_UBD
a7f7f624	151	help
1da177e4 LT	152	Writes to the virtual block device are not immediately written to the
	153	host's disk; this may cause problems if, for example, the User-Mode
	154	Linux 'Virtual Machine' uses a journalling filesystem and the host
	155	computer crashes.
	156
	157	Synchronous operation (i.e. always writing data to the host's disk
	158	immediately) is configurable on a per-UBD basis by using a special
	159	kernel command line option. Alternatively, you can say Y here to
	160	turn on synchronous operation by default for all block devices.
	161
	162	If you're running a journalling file system (like reiserfs, for
	163	example) in your virtual machine, you will want to say Y here. If
	164	you care for the safety of the data in your virtual machine, Y is a
	165	wise choice too. In all other cases (for example, if you're just
	166	playing around with User-Mode Linux) you can choose N.
	167
	168	config BLK_DEV_COW_COMMON
	169	bool
	170	default BLK_DEV_UBD
	171
1da177e4 LT	172	config BLK_DEV_LOOP
1da177e4 LT	173	tristate "Loopback device support"
a7f7f624	174	help
1da177e4 LT	175	Saying Y here will allow you to use a regular file as a block
	176	device; you can then create a file system on that block device and
	177	mount it just as you would mount other block devices such as hard
	178	drive partitions, CD-ROM drives or floppy drives. The loop devices
	179	are block special device files with major number 7 and typically
	180	called /dev/loop0, /dev/loop1 etc.
	181
	182	This is useful if you want to check an ISO 9660 file system before
	183	burning the CD, or if you want to use floppy images without first
	184	writing them to floppy. Furthermore, some Linux distributions avoid
	185	the need for a dedicated Linux partition by keeping their complete
	186	root file system inside a DOS FAT file using this loop device
	187	driver.
	188
	189	To use the loop device, you need the losetup utility, found in the
	190	util-linux package, see
4f6cce39	191	<https://www.kernel.org/pub/linux/utils/util-linux/>.
1da177e4 LT	192
	193	The loop device driver can also be used to "hide" a file system in
	194	a disk partition, floppy, or regular file, either using encryption
	195	(scrambling the data) or steganography (hiding the data in the low
	196	bits of, say, a sound file). This is also safe if the file resides
	197	on a remote file server.
	198
1da177e4 LT	199	Note that this loop device has nothing to do with the loopback
	200	device used for network connections from the machine to itself.
	201
	202	To compile this driver as a module, choose M here: the
	203	module will be called loop.
	204
	205	Most users will answer N here.
	206
d134b00b KS	207	config BLK_DEV_LOOP_MIN_COUNT
	208	int "Number of loop devices to pre-create at init time"
	209	depends on BLK_DEV_LOOP
	210	default 8
	211	help
	212	Static number of loop devices to be unconditionally pre-created
	213	at init time.
	214
	215	This default value can be overwritten on the kernel command
	216	line or with module-parameter loop.max_loop.
	217
	218	The historic default is 8. If a late 2011 version of losetup(8)
	219	is used, it can be set to 0, since needed loop devices can be
	220	dynamically allocated with the /dev/loop-control interface.
	221
b411b363 PR	222	source "drivers/block/drbd/Kconfig"
b411b363 PR	223
1da177e4 LT	224	config BLK_DEV_NBD
	225	tristate "Network block device support"
	226	depends on NET
a7f7f624	227	help
1da177e4 LT	228	Saying Y here will allow your computer to be a client for network
	229	block devices, i.e. it will be able to use block devices exported by
	230	servers (mount file systems on them etc.). Communication between
	231	client and server works over TCP/IP networking, but to the client
	232	program this is hidden: it looks like a regular local file access to
	233	a block device special file such as /dev/nd0.
	234
	235	Network block devices also allows you to run a block-device in
	236	userland (making server and client physically the same computer,
	237	communicating using the loopback network device).
	238
e7751617	239	Read <file:Documentation/admin-guide/blockdev/nbd.rst> for more information,
31c00fc1 RD	240	especially about where to find the server code, which runs in user
31c00fc1 RD	241	space and does not need special kernel support.
1da177e4 LT	242
	243	Note that this has nothing to do with the network file systems NFS
	244	or Coda; you can say N here even if you intend to use NFS or Coda.
	245
	246	To compile this driver as a module, choose M here: the
	247	module will be called nbd.
	248
	249	If unsure, say N.
	250
1da177e4	251	config BLK_DEV_RAM
9db5579b	252	tristate "RAM block device support"
a7f7f624	253	help
1da177e4 LT	254	Saying Y here will allow you to use a portion of your RAM memory as
	255	a block device, so that you can make file systems on it, read and
	256	write to it and do all the other things that you can do with normal
	257	block devices (such as hard drives). It is usually used to load and
	258	store a copy of a minimal root file system off of a floppy into RAM
	259	during the initial install of Linux.
	260
31c00fc1	261	Note that the kernel command line option "ramdisk=XX" is now obsolete.
e7751617	262	For details, read <file:Documentation/admin-guide/blockdev/ramdisk.rst>.
1da177e4 LT	263
1da177e4 LT	264	To compile this driver as a module, choose M here: the
a3b25d9b FF	265	module will be called brd. An alias "rd" has been defined
a3b25d9b FF	266	for historical reasons.
1da177e4 LT	267
	268	Most normal users won't need the RAM disk functionality, and can
	269	thus say N here.
	270
	271	config BLK_DEV_RAM_COUNT
a687fb18	272	int "Default number of RAM disks"
1da177e4	273	default "16"
a687fb18	274	depends on BLK_DEV_RAM
1da177e4	275	help
2e977c85	276	The default value is 16 RAM disks. Change this if you know what you
1da177e4 LT	277	are doing. If you boot from a filesystem that needs to be extracted
	278	in memory, you will need at least one RAM disk (e.g. root on cramfs).
	279
	280	config BLK_DEV_RAM_SIZE
	281	int "Default RAM disk size (kbytes)"
	282	depends on BLK_DEV_RAM
	283	default "4096"
	284	help
	285	The default value is 4096 kilobytes. Only change this if you know
2e977c85	286	what you are doing.
1da177e4	287
4b83e99e JA	288	config CDROM_PKTCDVD
	289	tristate "Packet writing on CD/DVD media (DEPRECATED)"
	290	depends on !UML
	291	depends on SCSI
	292	select CDROM
	293	help
	294	Note: This driver is deprecated and will be removed from the
	295	kernel in the near future!
	296
	297	If you have a CDROM/DVD drive that supports packet writing, say
	298	Y to include support. It should work with any MMC/Mt Fuji
	299	compliant ATAPI or SCSI drive, which is just about any newer
	300	DVD/CD writer.
	301
	302	Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs
	303	is possible.
	304	DVD-RW disks must be in restricted overwrite mode.
	305
	306	See the file <file:Documentation/cdrom/packet-writing.rst>
	307	for further information on the use of this driver.
	308
	309	To compile this driver as a module, choose M here: the
	310	module will be called pktcdvd.
	311
	312	config CDROM_PKTCDVD_BUFFERS
	313	int "Free buffers for data gathering"
	314	depends on CDROM_PKTCDVD
	315	default "8"
	316	help
	317	This controls the maximum number of active concurrent packets. More
	318	concurrent packets can increase write performance, but also require
	319	more memory. Each concurrent packet will require approximately 64Kb
	320	of non-swappable kernel memory, memory which will be allocated when
	321	a disc is opened for writing.
	322
	323	config CDROM_PKTCDVD_WCACHE
	324	bool "Enable write caching"
	325	depends on CDROM_PKTCDVD
	326	help
	327	If enabled, write caching will be set for the CD-R/W device. For now
	328	this option is dangerous unless the CD-RW media is known good, as we
	329	don't do deferred write error handling yet.
	330
1da177e4 LT	331	config ATA_OVER_ETH
	332	tristate "ATA over Ethernet support"
	333	depends on NET
	334	help
	335	This driver provides Support for ATA over Ethernet block
	336	devices like the Coraid EtherDrive (R) Storage Blade.
	337
667ef3c3 DM	338	config SUNVDC
	339	tristate "Sun Virtual Disk Client support"
	340	depends on SUN_LDOMS
	341	help
	342	Support for virtual disk devices as a client under Sun
	343	Logical Domains.
	344
61d48c2c	345	source "drivers/s390/block/Kconfig"
74489a91	346
9f27ee59 JF	347	config XEN_BLKDEV_FRONTEND
	348	tristate "Xen virtual block device support"
	349	depends on XEN
	350	default y
2de06cc1	351	select XEN_XENBUS_FRONTEND
9f27ee59 JF	352	help
	353	This driver implements the front-end of the Xen virtual
	354	block device driver. It communicates with a back-end driver
	355	in another domain which drives the actual block device.
	356
dfc07b13	357	config XEN_BLKDEV_BACKEND
ea5e1161	358	tristate "Xen block-device backend driver"
dfc07b13 KRW	359	depends on XEN_BACKEND
	360	help
	361	The block-device backend driver allows the kernel to export its
	362	block devices to other guests via a high-performance shared-memory
	363	interface.
	364
a4c34858 KRW	365	The corresponding Linux frontend driver is enabled by the
	366	CONFIG_XEN_BLKDEV_FRONTEND configuration option.
	367
	368	The backend driver attaches itself to a any block device specified
	369	in the XenBus configuration. There are no limits to what the block
	370	device as long as it has a major and minor.
	371
	372	If you are compiling a kernel to run in a Xen block backend driver
	373	domain (often this is domain 0) you should say Y here. To
	374	compile this driver as a module, chose M here: the module
	375	will be called xen-blkback.
	376
	377
e467cde2	378	config VIRTIO_BLK
b8977285 KC	379	tristate "Virtio block driver"
b8977285 KC	380	depends on VIRTIO
02746e26	381	select SG_POOL
a7f7f624	382	help
0ad07ec1	383	This is the virtual block driver for virtio. It can be used with
ecda85e7	384	QEMU based VMMs (like KVM or Xen). Say Y or M.
e467cde2	385
602adf40 YS	386	config BLK_DEV_RBD
602adf40 YS	387	tristate "Rados block device (RBD)"
b8977285	388	depends on INET && BLOCK
602adf40 YS	389	select CEPH_LIB
	390	select LIBCRC32C
	391	select CRYPTO_AES
	392	select CRYPTO
602adf40 YS	393	help
	394	Say Y here if you want include the Rados block device, which stripes
	395	a block device over objects stored in the Ceph distributed object
	396	store.
	397
	398	More information at http://ceph.newdream.net/.
	399
	400	If unsure, say N.
	401
71f28f31 ML	402	config BLK_DEV_UBLK
	403	tristate "Userspace block driver (Experimental)"
	404	select IO_URING
	405	help
	406	io_uring based userspace block driver. Together with ublk server, ublk
	407	has been working well, but interface with userspace or command data
	408	definition isn't finalized yet, and might change according to future
	409	requirement, so mark is as experimental now.
	410
d57c2c6c ML	411	Say Y if you want to get better performance because task_work_add()
	412	can be used in IO path for replacing io_uring cmd, which will become
	413	shared between IO tasks and ubq daemon, meantime task_work_add() can
	414	can handle batch more effectively, but task_work_add() isn't exported
	415	for module, so ublk has to be built to kernel.
	416
bc018853 JW	417	source "drivers/block/rnbd/Kconfig"
bc018853 JW	418
fd11d171	419	endif # BLK_DEV