| # | 
 | # Block layer core configuration | 
 | # | 
 | menuconfig BLOCK | 
 |        bool "Enable the block layer" if EMBEDDED | 
 |        default y | 
 |        help | 
 | 	 Provide block layer support for the kernel. | 
 |  | 
 | 	 Disable this option to remove the block layer support from the | 
 | 	 kernel. This may be useful for embedded devices. | 
 |  | 
 | 	 If this option is disabled: | 
 |  | 
 | 	   - block device files will become unusable | 
 | 	   - some filesystems (such as ext3) will become unavailable. | 
 |  | 
 | 	 Also, SCSI character devices and USB storage will be disabled since | 
 | 	 they make use of various block layer definitions and facilities. | 
 |  | 
 | 	 Say Y here unless you know you really don't want to mount disks and | 
 | 	 suchlike. | 
 |  | 
 | if BLOCK | 
 |  | 
 | config LBD | 
 | 	bool "Support for large block devices and files" | 
 | 	depends on !64BIT | 
 | 	help | 
 | 	  Enable block devices or files of size 2TB and larger. | 
 |  | 
 | 	  This option is required to support the full capacity of large | 
 | 	  (2TB+) block devices, including RAID, disk, Network Block Device, | 
 | 	  Logical Volume Manager (LVM) and loopback. | 
 | 	 | 
 | 	  This option also enables support for single files larger than | 
 | 	  2TB. | 
 |  | 
 | 	  The ext4 filesystem requires that this feature be enabled in | 
 | 	  order to support filesystems that have the huge_file feature | 
 | 	  enabled.    Otherwise, it will refuse to mount any filesystems | 
 | 	  that use the huge_file feature, which is enabled by default | 
 | 	  by mke2fs.ext4.   The GFS2 filesystem also requires this feature. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config BLK_DEV_IO_TRACE | 
 | 	bool "Support for tracing block io actions" | 
 | 	depends on SYSFS | 
 | 	select RELAY | 
 | 	select DEBUG_FS | 
 | 	select TRACEPOINTS | 
 | 	help | 
 | 	  Say Y here if you want to be able to trace the block layer actions | 
 | 	  on a given queue. Tracing allows you to see any traffic happening | 
 | 	  on a block device queue. For more information (and the userspace | 
 | 	  support tools needed), fetch the blktrace tools from: | 
 |  | 
 | 	  git://git.kernel.dk/blktrace.git | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config BLK_DEV_BSG | 
 | 	bool "Block layer SG support v4 (EXPERIMENTAL)" | 
 | 	depends on EXPERIMENTAL | 
 | 	---help--- | 
 | 	  Saying Y here will enable generic SG (SCSI generic) v4 support | 
 | 	  for any block device. | 
 |  | 
 | 	  Unlike SG v3 (aka block/scsi_ioctl.c drivers/scsi/sg.c), SG v4 | 
 | 	  can handle complicated SCSI commands: tagged variable length cdbs | 
 | 	  with bidirectional data transfers and generic request/response | 
 | 	  protocols (e.g. Task Management Functions and SMP in Serial | 
 | 	  Attached SCSI). | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config BLK_DEV_INTEGRITY | 
 | 	bool "Block layer data integrity support" | 
 | 	---help--- | 
 | 	Some storage devices allow extra information to be | 
 | 	stored/retrieved to help protect the data.  The block layer | 
 | 	data integrity option provides hooks which can be used by | 
 | 	filesystems to ensure better data integrity. | 
 |  | 
 | 	Say yes here if you have a storage device that provides the | 
 | 	T10/SCSI Data Integrity Field or the T13/ATA External Path | 
 | 	Protection.  If in doubt, say N. | 
 |  | 
 | endif # BLOCK | 
 |  | 
 | config BLOCK_COMPAT | 
 | 	bool | 
 | 	depends on BLOCK && COMPAT | 
 | 	default y | 
 |  | 
 | source block/Kconfig.iosched |