Merge tag 'docs-4.10' of git://git.lwn.net/linux

Pull documentation update from Jonathan Corbet:
 "These are the documentation changes for 4.10.

  It's another busy cycle for the docs tree, as the sphinx conversion
  continues. Highlights include:

   - Further work on PDF output, which remains a bit of a pain but
     should be more solid now.

   - Five more DocBook template files converted to Sphinx. Only 27 to
     go... Lots of plain-text files have also been converted and
     integrated.

   - Images in binary formats have been replaced with more
     source-friendly versions.

   - Various bits of organizational work, including the renaming of
     various files discussed at the kernel summit.

   - New documentation for the device_link mechanism.

  ... and, of course, lots of typo fixes and small updates"

* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
  dma-buf: Extract dma-buf.rst
  Update Documentation/00-INDEX
  docs: 00-INDEX: document directories/files with no docs
  docs: 00-INDEX: remove non-existing entries
  docs: 00-INDEX: add missing entries for documentation files/dirs
  docs: 00-INDEX: consolidate process/ and admin-guide/ description
  scripts: add a script to check if Documentation/00-INDEX is sane
  Docs: change sh -> awk in REPORTING-BUGS
  Documentation/core-api/device_link: Add initial documentation
  core-api: remove an unexpected unident
  ppc/idle: Add documentation for powersave=off
  Doc: Correct typo, "Introdution" => "Introduction"
  Documentation/atomic_ops.txt: convert to ReST markup
  Documentation/local_ops.txt: convert to ReST markup
  Documentation/assoc_array.txt: convert to ReST markup
  docs-rst: parse-headers.pl: cleanup the documentation
  docs-rst: fix media cleandocs target
  docs-rst: media/Makefile: reorganize the rules
  docs-rst: media: build SVG from graphviz files
  docs-rst: replace bayer.png by a SVG image
  ...

1 files changed, 0 insertions, 184 deletions

diff --git a/Documentation/sysfs-rules.txt b/Documentation/sysfs-rules.txt
deleted file mode 100644
index ce60ffa94d2d..000000000000
--- a/Documentation/sysfs-rules.txt
+++ /dev/null
@@ -1,184 +0,0 @@
-Rules on how to access information in the Linux kernel sysfs
-
-The kernel-exported sysfs exports internal kernel implementation details
-and depends on internal kernel structures and layout. It is agreed upon
-by the kernel developers that the Linux kernel does not provide a stable
-internal API. Therefore, there are aspects of the sysfs interface that
-may not be stable across kernel releases.
-
-To minimize the risk of breaking users of sysfs, which are in most cases
-low-level userspace applications, with a new kernel release, the users
-of sysfs must follow some rules to use an as-abstract-as-possible way to
-access this filesystem. The current udev and HAL programs already
-implement this and users are encouraged to plug, if possible, into the
-abstractions these programs provide instead of accessing sysfs directly.
-
-But if you really do want or need to access sysfs directly, please follow
-the following rules and then your programs should work with future
-versions of the sysfs interface.
-
-- Do not use libsysfs
-  It makes assumptions about sysfs which are not true. Its API does not
-  offer any abstraction, it exposes all the kernel driver-core
-  implementation details in its own API. Therefore it is not better than
-  reading directories and opening the files yourself.
-  Also, it is not actively maintained, in the sense of reflecting the
-  current kernel development. The goal of providing a stable interface
-  to sysfs has failed; it causes more problems than it solves. It
-  violates many of the rules in this document.
-
-- sysfs is always at /sys
-  Parsing /proc/mounts is a waste of time. Other mount points are a
-  system configuration bug you should not try to solve. For test cases,
-  possibly support a SYSFS_PATH environment variable to overwrite the
-  application's behavior, but never try to search for sysfs. Never try
-  to mount it, if you are not an early boot script.
-
-- devices are only "devices"
-  There is no such thing like class-, bus-, physical devices,
-  interfaces, and such that you can rely on in userspace. Everything is
-  just simply a "device". Class-, bus-, physical, ... types are just
-  kernel implementation details which should not be expected by
-  applications that look for devices in sysfs.
-
-  The properties of a device are:
-    o devpath (/devices/pci0000:00/0000:00:1d.1/usb2/2-2/2-2:1.0)
-      - identical to the DEVPATH value in the event sent from the kernel
-        at device creation and removal
-      - the unique key to the device at that point in time
-      - the kernel's path to the device directory without the leading
-        /sys, and always starting with a slash
-      - all elements of a devpath must be real directories. Symlinks
-        pointing to /sys/devices must always be resolved to their real
-        target and the target path must be used to access the device.
-        That way the devpath to the device matches the devpath of the
-        kernel used at event time.
-      - using or exposing symlink values as elements in a devpath string
-        is a bug in the application
-
-    o kernel name (sda, tty, 0000:00:1f.2, ...)
-      - a directory name, identical to the last element of the devpath
-      - applications need to handle spaces and characters like '!' in
-        the name
-
-    o subsystem (block, tty, pci, ...)
-      - simple string, never a path or a link
-      - retrieved by reading the "subsystem"-link and using only the
-        last element of the target path
-
-    o driver (tg3, ata_piix, uhci_hcd)
-      - a simple string, which may contain spaces, never a path or a
-        link
-      - it is retrieved by reading the "driver"-link and using only the
-        last element of the target path
-      - devices which do not have "driver"-link just do not have a
-        driver; copying the driver value in a child device context is a
-        bug in the application
-
-    o attributes
-      - the files in the device directory or files below subdirectories
-        of the same device directory
-      - accessing attributes reached by a symlink pointing to another device,
-        like the "device"-link, is a bug in the application
-
-  Everything else is just a kernel driver-core implementation detail
-  that should not be assumed to be stable across kernel releases.
-
-- Properties of parent devices never belong into a child device.
-  Always look at the parent devices themselves for determining device
-  context properties. If the device 'eth0' or 'sda' does not have a
-  "driver"-link, then this device does not have a driver. Its value is empty.
-  Never copy any property of the parent-device into a child-device. Parent
-  device properties may change dynamically without any notice to the
-  child device.
-
-- Hierarchy in a single device tree
-  There is only one valid place in sysfs where hierarchy can be examined
-  and this is below: /sys/devices.
-  It is planned that all device directories will end up in the tree
-  below this directory.
-
-- Classification by subsystem
-  There are currently three places for classification of devices:
-  /sys/block, /sys/class and /sys/bus. It is planned that these will
-  not contain any device directories themselves, but only flat lists of
-  symlinks pointing to the unified /sys/devices tree.
-  All three places have completely different rules on how to access
-  device information. It is planned to merge all three
-  classification directories into one place at /sys/subsystem,
-  following the layout of the bus directories. All buses and
-  classes, including the converted block subsystem, will show up
-  there.
-  The devices belonging to a subsystem will create a symlink in the
-  "devices" directory at /sys/subsystem/<name>/devices.
-
-  If /sys/subsystem exists, /sys/bus, /sys/class and /sys/block can be
-  ignored. If it does not exist, you always have to scan all three
-  places, as the kernel is free to move a subsystem from one place to
-  the other, as long as the devices are still reachable by the same
-  subsystem name.
-
-  Assuming /sys/class/<subsystem> and /sys/bus/<subsystem>, or
-  /sys/block and /sys/class/block are not interchangeable is a bug in
-  the application.
-
-- Block
-  The converted block subsystem at /sys/class/block or
-  /sys/subsystem/block will contain the links for disks and partitions
-  at the same level, never in a hierarchy. Assuming the block subsystem to
-  contain only disks and not partition devices in the same flat list is
-  a bug in the application.
-
-- "device"-link and <subsystem>:<kernel name>-links
-  Never depend on the "device"-link. The "device"-link is a workaround
-  for the old layout, where class devices are not created in
-  /sys/devices/ like the bus devices. If the link-resolving of a
-  device directory does not end in /sys/devices/, you can use the
-  "device"-link to find the parent devices in /sys/devices/. That is the
-  single valid use of the "device"-link; it must never appear in any
-  path as an element. Assuming the existence of the "device"-link for
-  a device in /sys/devices/ is a bug in the application.
-  Accessing /sys/class/net/eth0/device is a bug in the application.
-
-  Never depend on the class-specific links back to the /sys/class
-  directory.  These links are also a workaround for the design mistake
-  that class devices are not created in /sys/devices. If a device
-  directory does not contain directories for child devices, these links
-  may be used to find the child devices in /sys/class. That is the single
-  valid use of these links; they must never appear in any path as an
-  element. Assuming the existence of these links for devices which are
-  real child device directories in the /sys/devices tree is a bug in
-  the application.
-
-  It is planned to remove all these links when all class device
-  directories live in /sys/devices.
-
-- Position of devices along device chain can change.
-  Never depend on a specific parent device position in the devpath,
-  or the chain of parent devices. The kernel is free to insert devices into
-  the chain. You must always request the parent device you are looking for
-  by its subsystem value. You need to walk up the chain until you find
-  the device that matches the expected subsystem. Depending on a specific
-  position of a parent device or exposing relative paths using "../" to
-  access the chain of parents is a bug in the application.
-
-- When reading and writing sysfs device attribute files, avoid dependency
-  on specific error codes wherever possible. This minimizes coupling to
-  the error handling implementation within the kernel.
-
-  In general, failures to read or write sysfs device attributes shall
-  propagate errors wherever possible. Common errors include, but are not
-  limited to:
-
-  -EIO: The read or store operation is not supported, typically returned by
-        the sysfs system itself if the read or store pointer is NULL.
-
-  -ENXIO: The read or store operation failed
-
-  Error codes will not be changed without good reason, and should a change
-  to error codes result in user-space breakage, it will be fixed, or the
-  the offending change will be reverted.
-
-  Userspace applications can, however, expect the format and contents of
-  the attribute files to remain consistent in the absence of a version
-  attribute change in the context of a given attribute.