1# SPDX-License-Identifier: GPL-2.0 2# 3# Block device driver configuration 4# 5 6menuconfig BLK_DEV 7 bool "Block devices" 8 depends on BLOCK 9 default y 10 help 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. 16 17if BLK_DEV 18 19source "drivers/block/null_blk/Kconfig" 20 21config BLK_DEV_FD 22 tristate "Normal floppy disk support" 23 depends on ARCH_MAY_HAVE_PC_FDC 24 help 25 If you want to use the floppy disk drive(s) of your PC under Linux, 26 say Y. Information about this driver, especially important for IBM 27 Thinkpad users, is contained in 28 <file:Documentation/admin-guide/blockdev/floppy.rst>. 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 36config 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 52config AMIGA_FLOPPY 53 tristate "Amiga floppy support" 54 depends on AMIGA 55 56config ATARI_FLOPPY 57 tristate "Atari floppy support" 58 depends on ATARI 59 60config 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 67config BLK_DEV_SWIM 68 tristate "Support for SWIM Macintosh floppy" 69 depends on M68K && MAC && !HIGHMEM 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 74config 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 85config N64CART 86 bool "N64 cart support" 87 depends on MACH_NINTENDO64 88 help 89 Support for the N64 cart. 90 91config CDROM 92 tristate 93 94config GDROM 95 tristate "SEGA Dreamcast GD-ROM drive" 96 depends on SH_DREAMCAST 97 select CDROM 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 106source "drivers/block/mtip32xx/Kconfig" 107 108source "drivers/block/zram/Kconfig" 109 110config BLK_DEV_UBD 111 bool "Virtual block device" 112 depends on UML 113 help 114 The User-Mode Linux port includes a driver called UBD which will let 115 you access arbitrary files on the host computer as block devices. 116 Unless you know that you do not need such virtual block devices say 117 Y here. 118 119config BLK_DEV_UBD_SYNC 120 bool "Always do synchronous disk IO for UBD" 121 depends on BLK_DEV_UBD 122 help 123 Writes to the virtual block device are not immediately written to the 124 host's disk; this may cause problems if, for example, the User-Mode 125 Linux 'Virtual Machine' uses a journalling filesystem and the host 126 computer crashes. 127 128 Synchronous operation (i.e. always writing data to the host's disk 129 immediately) is configurable on a per-UBD basis by using a special 130 kernel command line option. Alternatively, you can say Y here to 131 turn on synchronous operation by default for all block devices. 132 133 If you're running a journalling file system (like reiserfs, for 134 example) in your virtual machine, you will want to say Y here. If 135 you care for the safety of the data in your virtual machine, Y is a 136 wise choice too. In all other cases (for example, if you're just 137 playing around with User-Mode Linux) you can choose N. 138 139config BLK_DEV_COW_COMMON 140 bool 141 default BLK_DEV_UBD 142 143config BLK_DEV_LOOP 144 tristate "Loopback device support" 145 help 146 Saying Y here will allow you to use a regular file as a block 147 device; you can then create a file system on that block device and 148 mount it just as you would mount other block devices such as hard 149 drive partitions, CD-ROM drives or floppy drives. The loop devices 150 are block special device files with major number 7 and typically 151 called /dev/loop0, /dev/loop1 etc. 152 153 This is useful if you want to check an ISO 9660 file system before 154 burning the CD, or if you want to use floppy images without first 155 writing them to floppy. Furthermore, some Linux distributions avoid 156 the need for a dedicated Linux partition by keeping their complete 157 root file system inside a DOS FAT file using this loop device 158 driver. 159 160 To use the loop device, you need the losetup utility, found in the 161 util-linux package, see 162 <https://www.kernel.org/pub/linux/utils/util-linux/>. 163 164 The loop device driver can also be used to "hide" a file system in 165 a disk partition, floppy, or regular file, either using encryption 166 (scrambling the data) or steganography (hiding the data in the low 167 bits of, say, a sound file). This is also safe if the file resides 168 on a remote file server. 169 170 Note that this loop device has nothing to do with the loopback 171 device used for network connections from the machine to itself. 172 173 To compile this driver as a module, choose M here: the 174 module will be called loop. 175 176 Most users will answer N here. 177 178config BLK_DEV_LOOP_MIN_COUNT 179 int "Number of loop devices to pre-create at init time" 180 depends on BLK_DEV_LOOP 181 default 8 182 help 183 Static number of loop devices to be unconditionally pre-created 184 at init time. 185 186 This default value can be overwritten on the kernel command 187 line or with module-parameter loop.max_loop. 188 189 The historic default is 8. If a late 2011 version of losetup(8) 190 is used, it can be set to 0, since needed loop devices can be 191 dynamically allocated with the /dev/loop-control interface. 192 193source "drivers/block/drbd/Kconfig" 194 195config BLK_DEV_NBD 196 tristate "Network block device support" 197 depends on NET 198 help 199 Saying Y here will allow your computer to be a client for network 200 block devices, i.e. it will be able to use block devices exported by 201 servers (mount file systems on them etc.). Communication between 202 client and server works over TCP/IP networking, but to the client 203 program this is hidden: it looks like a regular local file access to 204 a block device special file such as /dev/nd0. 205 206 Network block devices also allows you to run a block-device in 207 userland (making server and client physically the same computer, 208 communicating using the loopback network device). 209 210 Read <file:Documentation/admin-guide/blockdev/nbd.rst> for more information, 211 especially about where to find the server code, which runs in user 212 space and does not need special kernel support. 213 214 Note that this has nothing to do with the network file systems NFS 215 or Coda; you can say N here even if you intend to use NFS or Coda. 216 217 To compile this driver as a module, choose M here: the 218 module will be called nbd. 219 220 If unsure, say N. 221 222config BLK_DEV_RAM 223 tristate "RAM block device support" 224 help 225 Saying Y here will allow you to use a portion of your RAM memory as 226 a block device, so that you can make file systems on it, read and 227 write to it and do all the other things that you can do with normal 228 block devices (such as hard drives). It is usually used to load and 229 store a copy of a minimal root file system off of a floppy into RAM 230 during the initial install of Linux. 231 232 Note that the kernel command line option "ramdisk=XX" is now obsolete. 233 For details, read <file:Documentation/admin-guide/blockdev/ramdisk.rst>. 234 235 To compile this driver as a module, choose M here: the 236 module will be called brd. An alias "rd" has been defined 237 for historical reasons. 238 239 Most normal users won't need the RAM disk functionality, and can 240 thus say N here. 241 242config BLK_DEV_RAM_COUNT 243 int "Default number of RAM disks" 244 default "16" 245 depends on BLK_DEV_RAM 246 help 247 The default value is 16 RAM disks. Change this if you know what you 248 are doing. If you boot from a filesystem that needs to be extracted 249 in memory, you will need at least one RAM disk (e.g. root on cramfs). 250 251config BLK_DEV_RAM_SIZE 252 int "Default RAM disk size (kbytes)" 253 depends on BLK_DEV_RAM 254 default "4096" 255 help 256 The default value is 4096 kilobytes. Only change this if you know 257 what you are doing. 258 259config CDROM_PKTCDVD 260 tristate "Packet writing on CD/DVD media (DEPRECATED)" 261 depends on !UML 262 depends on SCSI 263 select CDROM 264 help 265 Note: This driver is deprecated and will be removed from the 266 kernel in the near future! 267 268 If you have a CDROM/DVD drive that supports packet writing, say 269 Y to include support. It should work with any MMC/Mt Fuji 270 compliant ATAPI or SCSI drive, which is just about any newer 271 DVD/CD writer. 272 273 Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs 274 is possible. 275 DVD-RW disks must be in restricted overwrite mode. 276 277 See the file <file:Documentation/cdrom/packet-writing.rst> 278 for further information on the use of this driver. 279 280 To compile this driver as a module, choose M here: the 281 module will be called pktcdvd. 282 283config CDROM_PKTCDVD_BUFFERS 284 int "Free buffers for data gathering" 285 depends on CDROM_PKTCDVD 286 default "8" 287 help 288 This controls the maximum number of active concurrent packets. More 289 concurrent packets can increase write performance, but also require 290 more memory. Each concurrent packet will require approximately 64Kb 291 of non-swappable kernel memory, memory which will be allocated when 292 a disc is opened for writing. 293 294config CDROM_PKTCDVD_WCACHE 295 bool "Enable write caching" 296 depends on CDROM_PKTCDVD 297 help 298 If enabled, write caching will be set for the CD-R/W device. For now 299 this option is dangerous unless the CD-RW media is known good, as we 300 don't do deferred write error handling yet. 301 302config ATA_OVER_ETH 303 tristate "ATA over Ethernet support" 304 depends on NET 305 help 306 This driver provides Support for ATA over Ethernet block 307 devices like the Coraid EtherDrive (R) Storage Blade. 308 309config SUNVDC 310 tristate "Sun Virtual Disk Client support" 311 depends on SUN_LDOMS 312 help 313 Support for virtual disk devices as a client under Sun 314 Logical Domains. 315 316source "drivers/s390/block/Kconfig" 317 318config XEN_BLKDEV_FRONTEND 319 tristate "Xen virtual block device support" 320 depends on XEN 321 default y 322 select XEN_XENBUS_FRONTEND 323 help 324 This driver implements the front-end of the Xen virtual 325 block device driver. It communicates with a back-end driver 326 in another domain which drives the actual block device. 327 328config XEN_BLKDEV_BACKEND 329 tristate "Xen block-device backend driver" 330 depends on XEN_BACKEND 331 help 332 The block-device backend driver allows the kernel to export its 333 block devices to other guests via a high-performance shared-memory 334 interface. 335 336 The corresponding Linux frontend driver is enabled by the 337 CONFIG_XEN_BLKDEV_FRONTEND configuration option. 338 339 The backend driver attaches itself to a any block device specified 340 in the XenBus configuration. There are no limits to what the block 341 device as long as it has a major and minor. 342 343 If you are compiling a kernel to run in a Xen block backend driver 344 domain (often this is domain 0) you should say Y here. To 345 compile this driver as a module, chose M here: the module 346 will be called xen-blkback. 347 348 349config VIRTIO_BLK 350 tristate "Virtio block driver" 351 depends on VIRTIO 352 select SG_POOL 353 help 354 This is the virtual block driver for virtio. It can be used with 355 QEMU based VMMs (like KVM or Xen). Say Y or M. 356 357config BLK_DEV_RBD 358 tristate "Rados block device (RBD)" 359 depends on INET && BLOCK 360 select CEPH_LIB 361 select LIBCRC32C 362 select CRYPTO_AES 363 select CRYPTO 364 help 365 Say Y here if you want include the Rados block device, which stripes 366 a block device over objects stored in the Ceph distributed object 367 store. 368 369 More information at http://ceph.newdream.net/. 370 371 If unsure, say N. 372 373config BLK_DEV_UBLK 374 tristate "Userspace block driver (Experimental)" 375 select IO_URING 376 help 377 io_uring based userspace block driver. Together with ublk server, ublk 378 has been working well, but interface with userspace or command data 379 definition isn't finalized yet, and might change according to future 380 requirement, so mark is as experimental now. 381 382 Say Y if you want to get better performance because task_work_add() 383 can be used in IO path for replacing io_uring cmd, which will become 384 shared between IO tasks and ubq daemon, meantime task_work_add() can 385 can handle batch more effectively, but task_work_add() isn't exported 386 for module, so ublk has to be built to kernel. 387 388config BLKDEV_UBLK_LEGACY_OPCODES 389 bool "Support legacy command opcode" 390 depends on BLK_DEV_UBLK 391 default y 392 help 393 ublk driver started to take plain command encoding, which turns out 394 one bad way. The traditional ioctl command opcode encodes more 395 info and basically defines each code uniquely, so opcode conflict 396 is avoided, and driver can handle wrong command easily, meantime it 397 may help security subsystem to audit io_uring command. 398 399 Say Y if your application still uses legacy command opcode. 400 401 Say N if you don't want to support legacy command opcode. It is 402 suggested to enable N if your application(ublk server) switches to 403 ioctl command encoding. 404 405source "drivers/block/rnbd/Kconfig" 406 407endif # BLK_DEV 408