WSL2-Linux-Kernel/Documentation/ABI
Linus Torvalds eafdca4d70 Staging/IIO patches for 4.18-rc1
Here is the big staging and IIO driver update for 4.18-rc1.
 
 It was delayed as I wanted to make sure the final driver deletions did
 not cause any major merge issues, and all now looks good.
 
 There are a lot of patches here, just over 1000.  The diffstat summary
 shows the major changes here:
 	1007 files changed, 16828 insertions(+), 227770 deletions(-)
 Because of this, we might be close to shrinking the overall kernel
 source code size for two releases in a row.
 
 There was loads of work in this release cycle, primarily:
 	- tons of ks7010 driver cleanups
 	- lots of mt7621 driver fixes and cleanups
 	- most driver cleanups
 	- wilc1000 fixes and cleanups
 	- lots and lots of IIO driver cleanups and new additions
 	- debugfs cleanups for all staging drivers
 	- lots of other staging driver cleanups and fixes, the shortlog
 	  has the full details.
 
 but the big user-visable things here are the removal of 3 chunks of
 code:
 	- ncpfs and ipx were removed on schedule, no one has cared about
 	  this code since it moved to staging last year, and if it needs
 	  to come back, it can be reverted.
 	- lustre file system is removed.  I've ranted at the lustre
 	  developers about once a year for the past 5 years, with no
 	  real forward progress at all to clean things up and get the
 	  code into the "real" part of the kernel.  Given that the
 	  lustre developers continue to work on an external tree and try
 	  to port those changes to the in-kernel tree every once in a
 	  while, this whole thing really really is not working out at
 	  all.  So I'm deleting it so that the developers can spend the
 	  time working in their out-of-tree location and get things
 	  cleaned up properly to get merged into the tree correctly at a
 	  later date.
 
 Because of these file removals, you will have merge issues on some of
 these files (2 in the ipx code, 1 in the ncpfs code, and 1 in the
 atomisp driver).  Just delete those files, it's a simple merge :)
 
 All of this has been in linux-next for a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging/IIO updates from Greg KH:
 "Here is the big staging and IIO driver update for 4.18-rc1.

  It was delayed as I wanted to make sure the final driver deletions did
  not cause any major merge issues, and all now looks good.

  There are a lot of patches here, just over 1000. The diffstat summary
  shows the major changes here:

	1007 files changed, 16828 insertions(+), 227770 deletions(-)

  Because of this, we might be close to shrinking the overall kernel
  source code size for two releases in a row.

  There was loads of work in this release cycle, primarily:

   - tons of ks7010 driver cleanups

   - lots of mt7621 driver fixes and cleanups

   - most driver cleanups

   - wilc1000 fixes and cleanups

   - lots and lots of IIO driver cleanups and new additions

   - debugfs cleanups for all staging drivers

   - lots of other staging driver cleanups and fixes, the shortlog has
     the full details.

  but the big user-visable things here are the removal of 3 chunks of
  code:

   - ncpfs and ipx were removed on schedule, no one has cared about this
     code since it moved to staging last year, and if it needs to come
     back, it can be reverted.

   - lustre file system is removed.

     I've ranted at the lustre developers about once a year for the past
     5 years, with no real forward progress at all to clean things up
     and get the code into the "real" part of the kernel.

     Given that the lustre developers continue to work on an external
     tree and try to port those changes to the in-kernel tree every once
     in a while, this whole thing really really is not working out at
     all. So I'm deleting it so that the developers can spend the time
     working in their out-of-tree location and get things cleaned up
     properly to get merged into the tree correctly at a later date.

  Because of these file removals, you will have merge issues on some of
  these files (2 in the ipx code, 1 in the ncpfs code, and 1 in the
  atomisp driver). Just delete those files, it's a simple merge :)

  All of this has been in linux-next for a while with no reported
  problems"

* tag 'staging-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (1011 commits)
  staging: ipx: delete it from the tree
  ncpfs: remove uapi .h files
  ncpfs: remove Documentation
  ncpfs: remove compat functionality
  staging: ncpfs: delete it
  staging: lustre: delete the filesystem from the tree.
  staging: vc04_services: no need to save the log debufs dentries
  staging: vc04_services: vchiq_debugfs_log_entry can be a void *
  staging: vc04_services: remove struct vchiq_debugfs_info
  staging: vc04_services: move client dbg directory into static variable
  staging: vc04_services: remove odd vchiq_debugfs_top() wrapper
  staging: vc04_services: no need to check debugfs return values
  staging: mt7621-gpio: reorder includes alphabetically
  staging: mt7621-gpio: change gc_map to don't use pointers
  staging: mt7621-gpio: use GPIOF_DIR_OUT and GPIOF_DIR_IN macros instead of custom values
  staging: mt7621-gpio: change 'to_mediatek_gpio' to make just a one line return
  staging: mt7621-gpio: dt-bindings: update documentation for #interrupt-cells property
  staging: mt7621-gpio: update #interrupt-cells for the gpio node
  staging: mt7621-gpio: dt-bindings: complete documentation for the gpio
  staging: mt7621-dts: add missing properties to gpio node
  ...
2018-06-09 10:32:39 -07:00
..
obsolete This is the bulk of GPIO changes for the v4.15 kernel cycle: 2017-11-14 17:23:44 -08:00
removed acpi, nfit: Remove ecc_unit_size 2018-06-03 12:49:15 -07:00
stable Char/Misc driver patches for 4.18-rc1 2018-06-05 16:20:22 -07:00
testing Staging/IIO patches for 4.18-rc1 2018-06-09 10:32:39 -07:00
README docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00

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.