Drop all 00-INDEX files from Documentation/

This is a respin with a wider audience (all that get_maintainer returned)
and I know this spams a *lot* of people. Not sure what would be the correct
way, so my apologies for ruining your inbox.

The 00-INDEX files are supposed to give a summary of all files present
in a directory, but these files are horribly out of date and their
usefulness is brought into question. Often a simple "ls" would reveal
the same information as the filenames are generally quite descriptive as
a short introduction to what the file covers (it should not surprise
anyone what Documentation/sched/sched-design-CFS.txt covers)

A few years back it was mentioned that these files were no longer really
needed, and they have since then grown further out of date, so perhaps
it is time to just throw them out.

A short status yields the following _outdated_ 00-INDEX files, first
counter is files listed in 00-INDEX but missing in the directory, last
is files present but not listed in 00-INDEX.

List of outdated 00-INDEX:
Documentation: (4/10)
Documentation/sysctl: (0/1)
Documentation/timers: (1/0)
Documentation/blockdev: (3/1)
Documentation/w1/slaves: (0/1)
Documentation/locking: (0/1)
Documentation/devicetree: (0/5)
Documentation/power: (1/1)
Documentation/powerpc: (0/5)
Documentation/arm: (1/0)
Documentation/x86: (0/9)
Documentation/x86/x86_64: (1/1)
Documentation/scsi: (4/4)
Documentation/filesystems: (2/9)
Documentation/filesystems/nfs: (0/2)
Documentation/cgroup-v1: (0/2)
Documentation/kbuild: (0/4)
Documentation/spi: (1/0)
Documentation/virtual/kvm: (1/0)
Documentation/scheduler: (0/2)
Documentation/fb: (0/1)
Documentation/block: (0/1)
Documentation/networking: (6/37)
Documentation/vm: (1/3)

Then there are 364 subdirectories in Documentation/ with several files that
are missing 00-INDEX alltogether (and another 120 with a single file and no
00-INDEX).

I don't really have an opinion to whether or not we /should/ have 00-INDEX,
but the above 00-INDEX should either be removed or be kept up to date. If
we should keep the files, I can try to keep them updated, but I rather not
if we just want to delete them anyway.

As a starting point, remove all index-files and references to 00-INDEX and
see where the discussion is going.

Signed-off-by: Henrik Austad <henrik@austad.us>
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Just-do-it-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: [Almost everybody else]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/virtual/00-INDEX

-Virtualization support in the Linux kernel.
-
-00-INDEX
-	- this file.
-
-paravirt_ops.txt
-	- Describes the Linux kernel pv_ops to support different hypervisors
-kvm/
-	- Kernel Virtual Machine.  See also http://linux-kvm.org
-uml/
-	- User Mode Linux, builds/runs Linux kernel as a userspace program.

Documentation/virtual/kvm/00-INDEX

-00-INDEX
-	- this file.
-amd-memory-encryption.rst
-	- notes on AMD Secure Encrypted Virtualization feature and SEV firmware
-	  command description
-api.txt
-	- KVM userspace API.
-arm
-	- internal ABI between the kernel and HYP (for arm/arm64)
-cpuid.txt
-	- KVM-specific cpuid leaves (x86).
-devices/
-	- KVM_CAP_DEVICE_CTRL userspace API.
-halt-polling.txt
-	- notes on halt-polling
-hypercalls.txt
-	- KVM hypercalls.
-locking.txt
-	- notes on KVM locks.
-mmu.txt
-	- the x86 kvm shadow mmu.
-msr.txt
-	- KVM-specific MSRs (x86).
-nested-vmx.txt
-	- notes on nested virtualization for Intel x86 processors.
-ppc-pv.txt
-	- the paravirtualization interface on PowerPC.
-review-checklist.txt
-	- review checklist for KVM patches.
-s390-diag.txt
-	- Diagnose hypercall description (for IBM S/390)
-timekeeping.txt
-	- timekeeping virtualization for x86-based architectures.
-vcpu-requests.rst
-	- internal VCPU request API

Documentation/vm/00-INDEX

-00-INDEX
-	- this file.
-active_mm.rst
-	- An explanation from Linus about tsk->active_mm vs tsk->mm.
-balance.rst
-	- various information on memory balancing.
-cleancache.rst
-	- Intro to cleancache and page-granularity victim cache.
-frontswap.rst
-	- Outline frontswap, part of the transcendent memory frontend.
-highmem.rst
-	- Outline of highmem and common issues.
-hmm.rst
-	- Documentation of heterogeneous memory management
-hugetlbfs_reserv.rst
-	- A brief overview of hugetlbfs reservation design/implementation.
-hwpoison.rst
-	- explains what hwpoison is
-ksm.rst
-	- how to use the Kernel Samepage Merging feature.
-mmu_notifier.rst
-	- a note about clearing pte/pmd and mmu notifications
-numa.rst
-	- information about NUMA specific code in the Linux vm.
-overcommit-accounting.rst
-	- description of the Linux kernels overcommit handling modes.
-page_frags.rst
-	- description of page fragments allocator
-page_migration.rst
-	- description of page migration in NUMA systems.
-page_owner.rst
-	- tracking about who allocated each page
-remap_file_pages.rst
-	- a note about remap_file_pages() system call
-slub.rst
-	- a short users guide for SLUB.
-split_page_table_lock.rst
-	- Separate per-table lock to improve scalability of the old page_table_lock.
-swap_numa.rst
-	- automatic binding of swap device to numa node
-transhuge.rst
-	- Transparent Hugepage Support, alternative way of using hugepages.
-unevictable-lru.rst
-	- Unevictable LRU infrastructure
-z3fold.txt
-	- outline of z3fold allocator for storing compressed pages
-zsmalloc.rst
-	- outline of zsmalloc allocator for storing compressed pages
-zswap.rst
-	- Intro to compressed cache for swap pages

Documentation/w1/00-INDEX

-00-INDEX
-	- This file
-slaves/
-	- Drivers that provide support for specific family codes.
-masters/
-	- Individual chips providing 1-wire busses.
-w1.generic
-	- The 1-wire (w1) bus
-w1.netlink
-	- Userspace communication protocol over connector [1].

Documentation/w1/masters/00-INDEX

-00-INDEX
-	- This file
-ds2482
-	- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
-ds2490
-	- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.
-mxc-w1
-	- W1 master controller driver found on Freescale MX2/MX3 SoCs
-omap-hdq
-	- HDQ/1-wire module of TI OMAP 2430/3430.
-w1-gpio
-	- GPIO 1-wire bus master driver.

Documentation/w1/slaves/00-INDEX

-00-INDEX
-	- This file
-w1_therm
-	- The Maxim/Dallas Semiconductor ds18*20 temperature sensor.
-w1_ds2413
-	- The Maxim/Dallas Semiconductor ds2413 dual channel addressable switch.
-w1_ds2423
-	- The Maxim/Dallas Semiconductor ds2423 counter device.
-w1_ds2438
-	- The Maxim/Dallas Semiconductor ds2438 smart battery monitor.
-w1_ds28e04
-	- The Maxim/Dallas Semiconductor ds28e04 eeprom.
-w1_ds28e17
-	- The Maxim/Dallas Semiconductor ds28e17 1-Wire-to-I2C Master Bridge.

Documentation/x86/00-INDEX

-00-INDEX
-	- this file
-boot.txt
-	- List of boot protocol versions
-earlyprintk.txt
-	- Using earlyprintk with a USB2 debug port key.
-entry_64.txt
-	- Describe (some of the) kernel entry points for x86.
-exception-tables.txt
-	- why and how Linux kernel uses exception tables on x86
-microcode.txt
-	- How to load microcode from an initrd-CPIO archive early to fix CPU issues.
-mtrr.txt
-	- how to use x86 Memory Type Range Registers to increase performance
-pat.txt
-	- Page Attribute Table intro and API
-usb-legacy-support.txt
-	- how to fix/avoid quirks when using emulated PS/2 mouse/keyboard.
-zero-page.txt
-	- layout of the first page of memory.

Documentation/x86/x86_64/00-INDEX

-00-INDEX
-	- This file
-boot-options.txt
-	- AMD64-specific boot options.
-cpu-hotplug-spec
-	- Firmware support for CPU hotplug under Linux/x86-64
-fake-numa-for-cpusets
-	- Using numa=fake and CPUSets for Resource Management
-kernel-stacks
-	- Context-specific per-processor interrupt stacks.
-machinecheck
-	- Configurable sysfs parameters for the x86-64 machine check code.
-mm.txt
-	- Memory layout of x86-64 (4 level page tables, 46 bits physical).
-uefi.txt
-	- Booting Linux via Unified Extensible Firmware Interface.

README

@@ -12,7 +12,6 @@ In order to build the documentation, use ``make htmldocs`` or
 
 There are various text files in the Documentation/ subdirectory,
 several of them using the Restructured Text markup notation.
-See Documentation/00-INDEX for a list of what is contained in each file.
 
 Please read the Documentation/process/changes.rst file, as it contains the
 requirements for building and running the kernel, and information about

scripts/check_00index.sh

-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-
-cd Documentation/
-
-# Check entries that should be removed
-
-obsolete=""
-for i in $(tail -n +12 00-INDEX |grep -E '^[a-zA-Z0-9]+'); do
-	if [ ! -e $i ]; then
-		obsolete="$obsolete $i"
-	fi
-done
-
-# Check directory entries that should be added
-search=""
-dir=""
-for i in $(find . -maxdepth 1 -type d); do
-	if [ "$i" != "." ]; then
-		new=$(echo $i|perl -ne 's,./(.*),$1/,; print $_')
-		search="$search $new"
-	fi
-done
-
-for i in $search; do
-	if [ "$(grep -P "^$i" 00-INDEX)" == "" ]; then
-		dir="$dir $i"
-	fi
-done
-
-# Check file entries that should be added
-search=""
-file=""
-for i in $(find . -maxdepth 1 -type f); do
-	if [ "$i" != "./.gitignore" ]; then
-		new=$(echo $i|perl -ne 's,./(.*),$1,; print $_')
-		search="$search $new"
-	fi
-done
-
-for i in $search; do
-	if [ "$(grep -P "^$i\$" 00-INDEX)" == "" ]; then
-		file="$file $i"
-	fi
-done
-
-# Output its findings
-
-echo -e "Documentation/00-INDEX check results:\n"
-
-if [ "$obsolete" != "" ]; then
-	echo -e "- Should remove those entries:\n\t$obsolete\n"
-else
-	echo -e "- No obsolete entries\n"
-fi
-
-if [ "$dir" != "" ]; then
-	echo -e "- Should document those directories:\n\t$dir\n"
-else
-	echo -e "- No new directories to add\n"
-fi
-
-if [ "$file" != "" ]; then
-	echo -e "- Should document those files:\n\t$file"
-else
-	echo "- No new files to add"
-fi