David Howells 9361401eb7 [PATCH] BLOCK: Make it possible to disable the block layer [try #6] ... Make it possible to disable the block layer. Not all embedded devices require it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require the block layer to be present. This patch does the following: (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev support. (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls an item that uses the block layer. This includes: (*) Block I/O tracing. (*) Disk partition code. (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS. (*) The SCSI layer. As far as I can tell, even SCSI chardevs use the block layer to do scheduling. Some drivers that use SCSI facilities - such as USB storage - end up disabled indirectly from this. (*) Various block-based device drivers, such as IDE and the old CDROM drivers. (*) MTD blockdev handling and FTL. (*) JFFS - which uses set_bdev_super(), something it could avoid doing by taking a leaf out of JFFS2's book. (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is, however, still used in places, and so is still available. (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and parts of linux/fs.h. (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK. (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK. (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK is not enabled. (*) fs/no-block.c is created to hold out-of-line stubs and things that are required when CONFIG_BLOCK is not set: (*) Default blockdev file operations (to give error ENODEV on opening). (*) Makes some /proc changes: (*) /proc/devices does not list any blockdevs. (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK. (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK. (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if given command other than Q_SYNC or if a special device is specified. (*) In init/do_mounts.c, no reference is made to the blockdev routines if CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2. (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return error ENOSYS by way of cond_syscall if so). (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if CONFIG_BLOCK is not set, since they can't then happen. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2006-09-30 20:52:31 +02:00
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as-iosched.c	[PATCH] Add blk_start_queueing() helper	2006-09-30 20:29:40 +02:00
blktrace.c	[PATCH] blktrace: cleanup using on_each_cpu	2006-09-30 20:31:19 +02:00
cfq-iosched.c	[PATCH] cfq-iosched: use metadata read flag	2006-09-30 20:29:43 +02:00
deadline-iosched.c	[PATCH] deadline-iosched: remove elevator private drq request type	2006-09-30 20:27:00 +02:00
elevator.c	[PATCH] Make sure all block/io scheduler setups are node aware	2006-09-30 20:29:39 +02:00
genhd.c	[PATCH] block: handle subsystem_register() init errors	2006-09-29 09:18:05 -07:00
ioctl.c	[PATCH] lockdep: annotate the BLKPG_DEL_PARTITION ioctl	2006-07-14 21:53:53 -07:00
Kconfig	[PATCH] BLOCK: Make it possible to disable the block layer [try #6]	2006-09-30 20:52:31 +02:00
Kconfig.iosched	[PATCH] BLOCK: Make it possible to disable the block layer [try #6]	2006-09-30 20:52:31 +02:00
ll_rw_blk.c	[PATCH] exit_io_context: don't disable irqs	2006-09-30 20:31:18 +02:00
Makefile	[PATCH] BLOCK: Make it possible to disable the block layer [try #6]	2006-09-30 20:52:31 +02:00
noop-iosched.c	[PATCH] Make sure all block/io scheduler setups are node aware	2006-09-30 20:29:39 +02:00
scsi_ioctl.c	[PATCH] Split struct request ->flags into two parts	2006-09-30 20:23:37 +02:00