linux/Documentation/ABI
Linus Torvalds dab363f938 Staging patches for 3.19-rc1
Here's the big staging tree pull request for 3.19-rc1.
 
 We continued to delete more lines than were added, always a good thing,
 but not at a huge rate this release, only about 70k lines removed
 overall mostly from removing the horrid bcm driver.
 
 Lots of normal staging driver cleanups and fixes all over the place,
 well over a thousand of them, the shortlog shows all the horrid details.
 
 The "contentious" thing here is the movement of the Android binder code
 out of staging into the "real" part of the kernel.  This is code that
 has been stable for a few years now and is working as-is in the tens of
 millions of devices with no issues.  Yes, the code is horrid, and the
 userspace api leaves a lot to be desired, but it's not going to change
 due to legacy issues that we have no control over.  Because so many
 devices and companies rely on this, and the code is stable, might as
 well promote it out of staging.
 
 This was all discussed at the Linux Plumbers conference, and everyone
 participating agreed that this was the best way forward.
 
 There is work happening to replace the binder code with something new
 that is happening right now, but I don't expect to see the results of
 that work for another year at the earliest.  If that ever happens, and
 Android switches over to it, I'll gladly remove this version.
 
 As for maintainers, I'll be glad to maintain this code, I've been doing
 it for the past few years with no problems.  I'll send a MAINTAINERS
 entry for it before 3.19-final is out, still need to talk to the Google
 developers about if they are willing to help with it or not, last I
 checked they were, which was good.
 
 All of these patches have been in linux-next for a while with no
 reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging driver updates from Greg KH:
 "Here's the big staging tree pull request for 3.19-rc1.

  We continued to delete more lines than were added, always a good
  thing, but not at a huge rate this release, only about 70k lines
  removed overall mostly from removing the horrid bcm driver.

  Lots of normal staging driver cleanups and fixes all over the place,
  well over a thousand of them, the shortlog shows all the horrid
  details.

  The "contentious" thing here is the movement of the Android binder
  code out of staging into the "real" part of the kernel.  This is code
  that has been stable for a few years now and is working as-is in the
  tens of millions of devices with no issues.  Yes, the code is horrid,
  and the userspace api leaves a lot to be desired, but it's not going
  to change due to legacy issues that we have no control over.  Because
  so many devices and companies rely on this, and the code is stable,
  might as well promote it out of staging.

  This was all discussed at the Linux Plumbers conference, and everyone
  participating agreed that this was the best way forward.

  There is work happening to replace the binder code with something new
  that is happening right now, but I don't expect to see the results of
  that work for another year at the earliest.  If that ever happens, and
  Android switches over to it, I'll gladly remove this version.

  As for maintainers, I'll be glad to maintain this code, I've been
  doing it for the past few years with no problems.  I'll send a
  MAINTAINERS entry for it before 3.19-final is out, still need to talk
  to the Google developers about if they are willing to help with it or
  not, last I checked they were, which was good.

  All of these patches have been in linux-next for a while with no
  reported issues"

* tag 'staging-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (1382 commits)
  Staging: slicoss: Fix long line issues in slicoss.c
  staging: rtl8712: remove unnecessary else after return
  staging: comedi: change some printk calls to pr_err
  staging: rtl8723au: hal: Removed the extra semicolon
  lustre: Deletion of unnecessary checks before three function calls
  staging: lustre: fix sparse warnings: static function declaration
  staging: lustre: fixed sparse warnings related to static declarations
  staging: unisys: remove duplicate header
  staging: unisys: remove unneeded structure
  staging: ft1000 : replace __attribute ((__packed__) with __packed
  drivers: staging: rtl8192e: Include "asm/unaligned.h" instead of "access_ok.h" in "rtl819x_BAProc.c"
  Drivers:staging:rtl8192e: Fixed checkpatch warning
  Drivers:staging:clocking-wizard: Added a newline
  staging: clocking-wizard: check for a valid clk_name pointer
  staging: rtl8723au: Hal_InitPGData() avoid unnecessary typecasts
  staging: rtl8723au: _DisableAnalog(): Avoid zero-init variables unnecessarily
  staging: rtl8723au: Remove unnecessary wrapper _ResetDigitalProcedure1()
  staging: rtl8723au: _ResetDigitalProcedure1_92C() reduce code obfuscation
  staging: rtl8723au: Remove unnecessary wrapper _DisableRFAFEAndResetBB()
  staging: rtl8723au: _DisableRFAFEAndResetBB8192C(): Reduce code obfuscation
  ...
2014-12-15 18:06:13 -08:00
..
obsolete Merge branches 'for-3.7/upstream-fixes', 'for-3.8/hidraw', 'for-3.8/i2c-hid', 'for-3.8/multitouch', 'for-3.8/roccat', 'for-3.8/sensors' and 'for-3.8/upstream' into for-linus 2012-12-12 21:41:55 +01:00
removed net_dma: simple removal 2014-09-28 07:05:16 -07:00
stable USB patches for 3.19-rc1 2014-12-14 14:57:16 -08:00
testing Staging patches for 3.19-rc1 2014-12-15 18:06:13 -08:00
README Documentation/ABI: document the non-ABI status of Kconfig and symbols 2013-11-13 12:09:32 +09:00

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/stable_api_nonsense.txt.