rbtree: Add generic add and find helpers

I've always been bothered by the endless (fragile) boilerplate for
rbtree, and I recently wrote some rbtree helpers for objtool and
figured I should lift them into the kernel and use them more widely.

Provide:

partial-order; less() based:
- rb_add(): add a new entry to the rbtree
- rb_add_cached(): like rb_add(), but for a rb_root_cached

total-order; cmp() based:
- rb_find(): find an entry in an rbtree
- rb_find_add(): find an entry, and add if not found

- rb_find_first(): find the first (leftmost) matching entry
- rb_next_match(): continue from rb_find_first()
- rb_for_each(): iterate a sub-tree using the previous two

Inlining and constant propagation should see the compiler inline the
whole thing, including the various compare functions.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Michel Lespinasse <walken@google.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>

docs: Add rbtree documentation to the core-api

This file is close enough to being in rst format that I didn't feel
the need to alter it in any way.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michel Lespinasse <walken@google.com>
Link: https://lore.kernel.org/r/20200401173343.17472-1-willy@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

rbtree: avoid generating code twice for the cached versions (tools copy)

As was already noted in rbtree.h, the logic to cache rb_first (or
rb_last) can easily be implemented externally to the core rbtree api.

This commit takes the changes applied to the include/linux/ and lib/
rbtree files in 9f973cb38088 ("lib/rbtree: avoid generating code twice
for the cached versions"), and applies these to the
tools/include/linux/ and tools/lib/ files as well to keep them
synchronized.

Link: http://lkml.kernel.org/r/20190703034812.53002-1-walken@google.com
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools: Update rbtree implementation

There have been a number of changes in the kernel's rbrtee
implementation, including loose lockless searching guarantees and
rb_root_cached, which later patches will use as an optimization.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181206191819.30182-2-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools: Move rbtree.h from tools/perf/

The previous step, copying the contents minus the rcupdate.h parts, was
done as a minimal fix, now do the move from tools/perf/.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-52fllxtsgmtke66pmv98mcma@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>