9361401eb7
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>
103 lines
3.4 KiB
C
103 lines
3.4 KiB
C
/*
|
|
md.h : Multiple Devices driver for Linux
|
|
Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
|
|
Copyright (C) 1994-96 Marc ZYNGIER
|
|
<zyngier@ufr-info-p7.ibp.fr> or
|
|
<maz@gloups.fdn.fr>
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2, or (at your option)
|
|
any later version.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
(for example /usr/src/linux/COPYING); if not, write to the Free
|
|
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#ifndef _MD_H
|
|
#define _MD_H
|
|
|
|
#include <linux/blkdev.h>
|
|
#include <asm/semaphore.h>
|
|
#include <linux/major.h>
|
|
#include <linux/ioctl.h>
|
|
#include <linux/types.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/module.h>
|
|
#include <linux/hdreg.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/delay.h>
|
|
#include <net/checksum.h>
|
|
#include <linux/random.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <asm/io.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/mempool.h>
|
|
#include <linux/list.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/blkpg.h>
|
|
#include <linux/bio.h>
|
|
|
|
/*
|
|
* 'md_p.h' holds the 'physical' layout of RAID devices
|
|
* 'md_u.h' holds the user <=> kernel API
|
|
*
|
|
* 'md_k.h' holds kernel internal definitions
|
|
*/
|
|
|
|
#include <linux/raid/md_p.h>
|
|
#include <linux/raid/md_u.h>
|
|
#include <linux/raid/md_k.h>
|
|
|
|
#ifdef CONFIG_MD
|
|
|
|
/*
|
|
* Different major versions are not compatible.
|
|
* Different minor versions are only downward compatible.
|
|
* Different patchlevel versions are downward and upward compatible.
|
|
*/
|
|
#define MD_MAJOR_VERSION 0
|
|
#define MD_MINOR_VERSION 90
|
|
/*
|
|
* MD_PATCHLEVEL_VERSION indicates kernel functionality.
|
|
* >=1 means different superblock formats are selectable using SET_ARRAY_INFO
|
|
* and major_version/minor_version accordingly
|
|
* >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT
|
|
* in the super status byte
|
|
* >=3 means that bitmap superblock version 4 is supported, which uses
|
|
* little-ending representation rather than host-endian
|
|
*/
|
|
#define MD_PATCHLEVEL_VERSION 3
|
|
|
|
extern int register_md_personality (struct mdk_personality *p);
|
|
extern int unregister_md_personality (struct mdk_personality *p);
|
|
extern mdk_thread_t * md_register_thread (void (*run) (mddev_t *mddev),
|
|
mddev_t *mddev, const char *name);
|
|
extern void md_unregister_thread (mdk_thread_t *thread);
|
|
extern void md_wakeup_thread(mdk_thread_t *thread);
|
|
extern void md_check_recovery(mddev_t *mddev);
|
|
extern void md_write_start(mddev_t *mddev, struct bio *bi);
|
|
extern void md_write_end(mddev_t *mddev);
|
|
extern void md_handle_safemode(mddev_t *mddev);
|
|
extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
|
|
extern void md_error (mddev_t *mddev, mdk_rdev_t *rdev);
|
|
extern void md_unplug_mddev(mddev_t *mddev);
|
|
|
|
extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
|
|
sector_t sector, int size, struct page *page);
|
|
extern void md_super_wait(mddev_t *mddev);
|
|
extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
|
|
struct page *page, int rw);
|
|
extern void md_do_sync(mddev_t *mddev);
|
|
extern void md_new_event(mddev_t *mddev);
|
|
|
|
extern void md_update_sb(mddev_t * mddev);
|
|
|
|
#endif /* CONFIG_MD */
|
|
#endif
|
|
|