linux/mm
Kay Sievers 2b2af54a5b Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.

Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.

If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.

If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.

It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-15 09:50:49 -07:00
..
allocpercpu.c percpu: __percpu_depopulate_mask can take a const mask 2009-04-06 13:44:15 -07:00
backing-dev.c writeback: check for registered bdi in flusher add and inode dirty 2009-09-11 09:20:26 +02:00
bootmem.c kmemleak: Do not report alloc_bootmem blocks as leaks 2009-08-27 14:29:17 +01:00
bounce.c block: remove some includings of blktrace_api.h 2009-06-16 11:19:36 +02:00
debug-pagealloc.c generic debug pagealloc 2009-04-01 08:59:13 -07:00
dmapool.c dmapools: protect page_list walk in show_pools() 2009-06-30 18:56:00 -07:00
fadvise.c readahead: move max_sane_readahead() calls into force_page_cache_readahead() 2009-06-16 19:47:28 -07:00
failslab.c kmemtrace, mm: fix slab.h dependency problem in mm/failslab.c 2009-04-03 12:23:01 +02:00
filemap_xip.c mm: do_xip_mapping_read: fix length calculation 2009-04-02 19:04:49 -07:00
filemap.c vfs: Remove generic_osync_inode() and sync_page_range{_nolock}() 2009-09-14 17:08:17 +02:00
fremap.c Do not account for the address space used by hugetlbfs using VM_ACCOUNT 2009-02-10 10:48:42 -08:00
highmem.c block: remove some includings of blktrace_api.h 2009-06-16 11:19:36 +02:00
hugetlb.c hugetlbfs: export vma_kernel_pagsize to modules 2009-09-10 08:33:01 +03:00
init-mm.c mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
internal.h vmscan: do not unconditionally treat zones that fail zone_reclaim() as full 2009-06-16 19:47:45 -07:00
Kconfig Security/SELinux: seperate lsm specific mmap_min_addr 2009-08-17 15:09:11 +10:00
Kconfig.debug kmemcheck: enable in the x86 Kconfig 2009-06-15 15:49:15 +02:00
kmemcheck.c kmemcheck: add hooks for the page allocator 2009-06-15 15:48:33 +02:00
kmemleak-test.c kmemleak: Simple testing module for kmemleak 2009-06-11 17:04:19 +01:00
kmemleak.c kmemleak: Improve the "Early log buffer exceeded" error message 2009-09-11 10:42:09 +01:00
maccess.c [S390] maccess: add weak attribute to probe_kernel_write 2009-06-12 10:27:37 +02:00
madvise.c mm: madvise(): correct return code 2009-06-16 19:47:40 -07:00
Makefile writeback: get rid of pdflush completely 2009-09-11 09:20:25 +02:00
memcontrol.c cgroup avoid permanent sleep at rmdir 2009-07-29 19:10:35 -07:00
memory_hotplug.c page-allocator: reset wmark_min and inactive ratio of zone when hotplug happens 2009-06-16 19:47:42 -07:00
memory.c mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
mempolicy.c mm: make set_mempolicy(MPOL_INTERLEAV) N_HIGH_MEMORY aware 2009-08-07 10:39:55 -07:00
mempool.c mempool.c: clean up type-casting 2009-08-10 08:31:16 -07:00
migrate.c migration: only migrate_prep() once per move_pages() 2009-06-16 19:47:41 -07:00
mincore.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
mlock.c mm: remove CONFIG_UNEVICTABLE_LRU config option 2009-06-16 19:47:42 -07:00
mm_init.c mm: mminit_loglevel cannot be __meminitdata anymore 2008-08-20 15:40:30 -07:00
mmap.c Security/SELinux: seperate lsm specific mmap_min_addr 2009-08-17 15:09:11 +10:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c [ARM] Double check memmap is actually valid with a memmap has unexpected holes V2 2009-05-18 11:22:24 +01:00
mprotect.c perf_counter: Add mmap event hooks to mprotect() 2009-06-08 23:10:43 +02:00
mremap.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
msync.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
nommu.c nommu: fix error handling in do_mmap_pgoff() 2009-09-05 11:30:42 -07:00
oom_kill.c mm: revert "oom: move oom_adj value" 2009-08-18 16:31:13 -07:00
page_alloc.c page-allocator: always change pageblock ownership when anti-fragmentation is disabled 2009-09-05 11:30:42 -07:00
page_cgroup.c memcg: remove some redundant checks 2009-06-18 13:03:47 -07:00
page_io.c mm: remove file argument from swap_readpage() 2009-06-16 19:47:44 -07:00
page_isolation.c memory hotplug: fix page_zone() calculation in test_pages_isolated() 2008-11-06 15:41:19 -08:00
page-writeback.c writeback: switch to per-bdi threads for flushing data 2009-09-11 09:20:25 +02:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
percpu.c percpu: don't assume existence of cpu0 2009-09-01 21:23:18 +09:00
prio_tree.c
quicklist.c cpumask: replace node_to_cpumask with cpumask_of_node. 2009-03-13 14:49:46 +10:30
readahead.c readahead: introduce context readahead algorithm 2009-06-16 19:47:30 -07:00
rmap.c mm: fix for infinite churning of mlocked pages 2009-08-26 20:06:52 -07:00
shmem_acl.c shmfs: use 'check_acl' instead of 'permission' 2009-09-08 11:08:46 -07:00
shmem.c Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev 2009-09-15 09:50:49 -07:00
slab.c SLAB: Fix lockdep annotations 2009-06-29 09:57:10 +03:00
slob.c slab: remove duplicate kmem_cache_init_late() declarations 2009-08-06 11:36:25 +03:00
slub.c Merge branches 'slab/cleanups' and 'slab/fixes' into for-linus 2009-09-14 20:19:06 +03:00
sparse-vmemmap.c vmemmap: warn about page_structs with remote distance 2008-11-06 15:41:19 -08:00
sparse.c mm: mminit_validate_memmodel_limits(): remove redundant test 2009-04-01 08:59:11 -07:00
swap_state.c writeback: add name to backing_dev_info 2009-09-11 09:20:26 +02:00
swap.c mm: fix Committed_AS underflow on large NR_CPUS environment 2009-05-02 15:36:10 -07:00
swapfile.c block: use blkdev_issue_discard in blk_ioctl_discard 2009-09-14 08:24:53 +02:00
thrash.c mm: pass mm to grab_swap_token 2009-06-23 12:50:05 -07:00
truncate.c mm: remove __invalidate_mapping_pages variant 2009-06-16 19:47:43 -07:00
util.c Merge branches 'slab/documentation', 'slab/fixes', 'slob/cleanups' and 'slub/fixes' into for-linus 2009-06-17 08:30:15 +03:00
vmalloc.c Merge branch 'for-linus' of git://linux-arm.org/linux-2.6 2009-06-11 14:15:57 -07:00
vmscan.c writeback: switch to per-bdi threads for flushing data 2009-09-11 09:20:25 +02:00
vmstat.c vmscan: count the number of times zone_reclaim() scans and fails 2009-06-16 19:47:46 -07:00