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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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"source "drivers/block/rnull/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.
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 xfs, 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 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 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.
config BLKDEV_UBLK_LEGACY_OPCODES bool "Support legacy command opcode" depends on BLK_DEV_UBLK default y help ublk driver started to take plain command encoding, which turns out one bad way. The traditional ioctl command opcode encodes more info and basically defines each code uniquely, so opcode conflict is avoided, and driver can handle wrong command easily, meantime it may help security subsystem to audit io_uring command.
Say Y if your application still uses legacy command opcode.
Say N if you don't want to support legacy command opcode. It is suggested to enable N if your application(ublk server) switches to ioctl command encoding.
source "drivers/block/rnbd/Kconfig"
config BLK_DEV_ZONED_LOOP tristate "Zoned loopback device support" depends on BLK_DEV_ZONED help Saying Y here will allow you to use create a zoned block device using regular files for zones (one file per zones). This is useful to test file systems, device mapper and applications that support zoned block devices. To create a zoned loop device, no user utility is needed, a zoned loop device can be created (or re-started) using a command like:
echo "add id=0,zone_size_mb=256,capacity_mb=16384,conv_zones=11" > \ /dev/zloop-control
See Documentation/admin-guide/blockdev/zoned_loop.rst for usage details.
If unsure, say N.
endif # BLK_DEV