linux/Documentation/ABI
Linus Torvalds 9ab97aea85 f2fs-for-4.21-rc1
In this round, we've focused on bug fixes since Pixel devices have been
 shipping with f2fs. Some of them were related to hardware encryption support
 which are actually not an issue in mainline, but would be better to merge
 them in order to avoid potential bugs.
 
 Enhancement:
  - do GC sub-sections when the section is large
  - add a flag in ioctl(SHUTDOWN) to trigger fsck for QA
  - use kvmalloc() in order to give another chance to avoid ENOMEM
 
 Bug fix:
  - fix accessing memory boundaries in a malformed iamge
  - GC gives stale unencrypted block
  - GC counts in large sections
  - detect idle time more precisely
  - block allocation of DIO writes
  - race conditions between write_begin and write_checkpoint
  - allow GCs for node segments via ioctl()
 
 There are various clean-ups and minor bug fixes as well.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEE00UqedjCtOrGVvQiQBSofoJIUNIFAlwmkzcACgkQQBSofoJI
 UNLIlw//RUd8rH8VMW/BcXQ3fwB8qFCk296cIVlWQu12BV7vmMKY886Sc+C9uAuR
 9Lze4D6Iyg1k2KLkaWKhnE2E4ZWQ2O5zVf11r4amm1bN9glPJAKfLWbenJhMfeGa
 IdWo1ksntxgjfqLim2QlGSv5cBUjEo8zf32D446BbQURQMD/mm/lndywItS5vTx1
 2eGKJ3pSXX6geFzyf1pD/wmC/7j6roKaTKAIMBagIuINNukeHctT/gRfklmYmOFC
 lRbXlsYhjIfGln6gktY6r4qyZbouOMad2fDl+dkp+UewQM4/2xLUaMqiN2eqd7Hr
 cag9LGe80MGgWwesqS6VOJHQviOlNd78Ie//iO1+ZsaIxKrvgzocRSDdxZswv+Vq
 reZNsEKH0s4/0ik9hiprW1NdQLvtg7e/UWPyrRvVRlDVitW/BXOWRBpGVgkdg01K
 OmAxNrVcr2+Gxp8jZL7M+rQdpApL/ms31x9HE/8u5ABBZfmCy3zhpICTZ6Hdngp1
 3iUi2PvKUg+Y7KgII1nK2HLDpmZZ5UkLm8NhxLI0ntBWExjQjOBasOxPJf4en/UR
 TAtK3ozNKim3fQ01NCBy3B8WMKRtovxLK6PgqNPROJparlKJ3FEHnPIrYKglDUPg
 sxWCm1gFSraRGP86TaeGeD+v+PP6erI9CTaf6F/U3pWFgIpHoPg=
 =NEns
 -----END PGP SIGNATURE-----

Merge tag 'f2fs-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've focused on bug fixes since Pixel devices have
  been shipping with f2fs. Some of them were related to hardware
  encryption support which are actually not an issue in mainline, but
  would be better to merge them in order to avoid potential bugs.

  Enhancements:
   - do GC sub-sections when the section is large
   - add a flag in ioctl(SHUTDOWN) to trigger fsck for QA
   - use kvmalloc() in order to give another chance to avoid ENOMEM

  Bug fixes:
   - fix accessing memory boundaries in a malformed iamge
   - GC gives stale unencrypted block
   - GC counts in large sections
   - detect idle time more precisely
   - block allocation of DIO writes
   - race conditions between write_begin and write_checkpoint
   - allow GCs for node segments via ioctl()

  There are various clean-ups and minor bug fixes as well"

* tag 'f2fs-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (43 commits)
  f2fs: sanity check of xattr entry size
  f2fs: fix use-after-free issue when accessing sbi->stat_info
  f2fs: check PageWriteback flag for ordered case
  f2fs: fix validation of the block count in sanity_check_raw_super
  f2fs: fix missing unlock(sbi->gc_mutex)
  f2fs: fix to dirty inode synchronously
  f2fs: clean up structure extent_node
  f2fs: fix block address for __check_sit_bitmap
  f2fs: fix sbi->extent_list corruption issue
  f2fs: clean up checkpoint flow
  f2fs: flush stale issued discard candidates
  f2fs: correct wrong spelling, issing_*
  f2fs: use kvmalloc, if kmalloc is failed
  f2fs: remove redundant comment of unused wio_mutex
  f2fs: fix to reorder set_page_dirty and wait_on_page_writeback
  f2fs: clear PG_writeback if IPU failed
  f2fs: add an ioctl() to explicitly trigger fsck later
  f2fs: avoid frequent costly fsck triggers
  f2fs: fix m_may_create to make OPU DIO write correctly
  f2fs: fix to update new block address correctly for OPU
  ...
2018-12-31 09:41:37 -08:00
..
obsolete usb: typec: Bus type for alternate modes 2018-07-02 17:42:36 +02:00
removed acpi, nfit: Remove ecc_unit_size 2018-06-03 12:49:15 -07:00
stable Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces 2018-12-10 17:54:41 -08:00
testing f2fs-for-4.21-rc1 2018-12-31 09:41:37 -08:00
README

README

This directory attempts to document the ABI between the Linux kernel and
userspace, and the relative stability of these interfaces.  Due to the
everchanging nature of Linux, and the differing maturity levels, these
interfaces should be used by userspace programs in different ways.

We have four different levels of ABI stability, as shown by the four
different subdirectories in this location.  Interfaces may change levels
of stability according to the rules described below.

The different levels of stability are:

  stable/
	This directory documents the interfaces that the developer has
	defined to be stable.  Userspace programs are free to use these
	interfaces with no restrictions, and backward compatibility for
	them will be guaranteed for at least 2 years.  Most interfaces
	(like syscalls) are expected to never change and always be
	available.

  testing/
	This directory documents interfaces that are felt to be stable,
	as the main development of this interface has been completed.
	The interface can be changed to add new features, but the
	current interface will not break by doing this, unless grave
	errors or security problems are found in them.  Userspace
	programs can start to rely on these interfaces, but they must be
	aware of changes that can occur before these interfaces move to
	be marked stable.  Programs that use these interfaces are
	strongly encouraged to add their name to the description of
	these interfaces, so that the kernel developers can easily
	notify them if any changes occur (see the description of the
	layout of the files below for details on how to do this.)

  obsolete/
  	This directory documents interfaces that are still remaining in
	the kernel, but are marked to be removed at some later point in
	time.  The description of the interface will document the reason
	why it is obsolete and when it can be expected to be removed.

  removed/
	This directory contains a list of the old interfaces that have
	been removed from the kernel.

Every file in these directories will contain the following information:

What:		Short description of the interface
Date:		Date created
KernelVersion:	Kernel version this feature first showed up in.
Contact:	Primary contact for this interface (may be a mailing list)
Description:	Long description of the interface and how to use it.
Users:		All users of this interface who wish to be notified when
		it changes.  This is very important for interfaces in
		the "testing" stage, so that kernel developers can work
		with userspace developers to ensure that things do not
		break in ways that are unacceptable.  It is also
		important to get feedback for these interfaces to make
		sure they are working in a proper way and do not need to
		be changed further.


How things move between levels:

Interfaces in stable may move to obsolete, as long as the proper
notification is given.

Interfaces may be removed from obsolete and the kernel as long as the
documented amount of time has gone by.

Interfaces in the testing state can move to the stable state when the
developers feel they are finished.  They cannot be removed from the
kernel tree without going through the obsolete state first.

It's up to the developer to place their interfaces in the category they
wish for it to start out in.


Notable bits of non-ABI, which should not under any circumstances be considered
stable:

- Kconfig.  Userspace should not rely on the presence or absence of any
  particular Kconfig symbol, in /proc/config.gz, in the copy of .config
  commonly installed to /boot, or in any invocation of the kernel build
  process.

- Kernel-internal symbols.  Do not rely on the presence, absence, location, or
  type of any kernel symbol, either in System.map files or the kernel binary
  itself.  See Documentation/process/stable-api-nonsense.rst.