From: Alexander Aring <aahringo@redhat.com>
To: teigland@redhat.com
Cc: cluster-devel@redhat.com
Subject: [Cluster-devel] [PATCH dlm-tool 1/3] dlm_controld: update rbtree implementation
Date: Mon, 21 Aug 2023 12:25:38 -0400 [thread overview]
Message-ID: <20230821162540.594227-1-aahringo@redhat.com> (raw)
This patch updates the rbtree implementation taken from the Linux
kernel.
---
README.license | 3 +
dlm_controld/linux_helpers.h | 11 +
dlm_controld/list.h | 1 -
dlm_controld/rbtree.c | 724 +++++++++++++++++++++-----------
dlm_controld/rbtree.h | 393 ++++++++++++-----
dlm_controld/rbtree_augmented.h | 303 +++++++++++++
dlm_controld/rbtree_types.h | 34 ++
7 files changed, 1097 insertions(+), 372 deletions(-)
create mode 100644 dlm_controld/linux_helpers.h
create mode 100644 dlm_controld/rbtree_augmented.h
create mode 100644 dlm_controld/rbtree_types.h
diff --git a/README.license b/README.license
index ededf669..d53f5894 100644
--- a/README.license
+++ b/README.license
@@ -7,10 +7,13 @@ libdlm/libdlm_internal.h
GPLv2
dlm_controld/list.h (copied from linux kernel)
+dlm_controld/linux_helpers.h (various GPLv2 functions copied from linux kernel)
GPLv2+
dlm_controld/rbtree.c (copied from linux kernel)
dlm_controld/rbtree.h (copied from linux kernel)
+dlm_controld/rbtree_augmented.h (copied from linux kernel)
+dlm_controld/rbtree_types.h (copied from linux kernel)
all other original files
diff --git a/dlm_controld/linux_helpers.h b/dlm_controld/linux_helpers.h
new file mode 100644
index 00000000..5ef13466
--- /dev/null
+++ b/dlm_controld/linux_helpers.h
@@ -0,0 +1,11 @@
+/* Copied from linux kernel */
+
+#ifndef __DLM_LINUX_HELPERS__
+#define __DLM_LINUX_HELPERS__
+
+#define WRITE_ONCE(x, val) \
+do { \
+ *(volatile typeof(x) *)&(x) = (val); \
+} while (0)
+
+#endif /* __DLM_LINUX_HELPERS__ */
diff --git a/dlm_controld/list.h b/dlm_controld/list.h
index 8100cbc7..a2a5e5f3 100644
--- a/dlm_controld/list.h
+++ b/dlm_controld/list.h
@@ -15,7 +15,6 @@
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
-
/*
* These are non-NULL pointers that will result in page faults
* under normal circumstances, used to verify that nobody uses
diff --git a/dlm_controld/rbtree.c b/dlm_controld/rbtree.c
index 9f49917d..d07ffc29 100644
--- a/dlm_controld/rbtree.c
+++ b/dlm_controld/rbtree.c
@@ -1,284 +1,458 @@
+/* Copied from linux/lib/rbtree.c */
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@suse.de>
(C) 2002 David Woodhouse <dwmw2@infradead.org>
-
- 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.
+ (C) 2012 Michel Lespinasse <walken@google.com>
- 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.
linux/lib/rbtree.c
*/
-#include <stdlib.h>
-#include "rbtree.h"
-
-static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
-{
- struct rb_node *right = node->rb_right;
- struct rb_node *parent = rb_parent(node);
+#include "rbtree_augmented.h"
- if ((node->rb_right = right->rb_left))
- rb_set_parent(right->rb_left, node);
- right->rb_left = node;
+/*
+ * red-black trees properties: https://en.wikipedia.org/wiki/Rbtree
+ *
+ * 1) A node is either red or black
+ * 2) The root is black
+ * 3) All leaves (NULL) are black
+ * 4) Both children of every red node are black
+ * 5) Every simple path from root to leaves contains the same number
+ * of black nodes.
+ *
+ * 4 and 5 give the O(log n) guarantee, since 4 implies you cannot have two
+ * consecutive red nodes in a path and every red node is therefore followed by
+ * a black. So if B is the number of black nodes on every simple path (as per
+ * 5), then the longest possible path due to 4 is 2B.
+ *
+ * We shall indicate color with case, where black nodes are uppercase and red
+ * nodes will be lowercase. Unknown color nodes shall be drawn as red within
+ * parentheses and have some accompanying text comment.
+ */
- rb_set_parent(right, parent);
+/*
+ * Notes on lockless lookups:
+ *
+ * All stores to the tree structure (rb_left and rb_right) must be done using
+ * WRITE_ONCE(). And we must not inadvertently cause (temporary) loops in the
+ * tree structure as seen in program order.
+ *
+ * These two requirements will allow lockless iteration of the tree -- not
+ * correct iteration mind you, tree rotations are not atomic so a lookup might
+ * miss entire subtrees.
+ *
+ * But they do guarantee that any such traversal will only see valid elements
+ * and that it will indeed complete -- does not get stuck in a loop.
+ *
+ * It also guarantees that if the lookup returns an element it is the 'correct'
+ * one. But not returning an element does _NOT_ mean it's not present.
+ *
+ * NOTE:
+ *
+ * Stores to __rb_parent_color are not important for simple lookups so those
+ * are left undone as of now. Nor did I check for loops involving parent
+ * pointers.
+ */
- if (parent)
- {
- if (node == parent->rb_left)
- parent->rb_left = right;
- else
- parent->rb_right = right;
- }
- else
- root->rb_node = right;
- rb_set_parent(node, right);
+static inline void rb_set_black(struct rb_node *rb)
+{
+ rb->__rb_parent_color += RB_BLACK;
}
-static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
+static inline struct rb_node *rb_red_parent(struct rb_node *red)
{
- struct rb_node *left = node->rb_left;
- struct rb_node *parent = rb_parent(node);
-
- if ((node->rb_left = left->rb_right))
- rb_set_parent(left->rb_right, node);
- left->rb_right = node;
-
- rb_set_parent(left, parent);
+ return (struct rb_node *)red->__rb_parent_color;
+}
- if (parent)
- {
- if (node == parent->rb_right)
- parent->rb_right = left;
- else
- parent->rb_left = left;
- }
- else
- root->rb_node = left;
- rb_set_parent(node, left);
+/*
+ * Helper function for rotations:
+ * - old's parent and color get assigned to new
+ * - old gets assigned new as a parent and 'color' as a color.
+ */
+static inline void
+__rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
+ struct rb_root *root, int color)
+{
+ struct rb_node *parent = rb_parent(old);
+ new->__rb_parent_color = old->__rb_parent_color;
+ rb_set_parent_color(old, new, color);
+ __rb_change_child(old, new, parent, root);
}
-void rb_insert_color(struct rb_node *node, struct rb_root *root)
+static __always_inline void
+__rb_insert(struct rb_node *node, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
- struct rb_node *parent, *gparent;
-
- while ((parent = rb_parent(node)) && rb_is_red(parent))
- {
- gparent = rb_parent(parent);
-
- if (parent == gparent->rb_left)
- {
- {
- register struct rb_node *uncle = gparent->rb_right;
- if (uncle && rb_is_red(uncle))
- {
- rb_set_black(uncle);
- rb_set_black(parent);
- rb_set_red(gparent);
- node = gparent;
- continue;
- }
+ struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
+
+ while (true) {
+ /*
+ * Loop invariant: node is red.
+ */
+ if (!parent) {
+ /*
+ * The inserted node is root. Either this is the
+ * first node, or we recursed at Case 1 below and
+ * are no longer violating 4).
+ */
+ rb_set_parent_color(node, NULL, RB_BLACK);
+ break;
+ }
+
+ /*
+ * If there is a black parent, we are done.
+ * Otherwise, take some corrective action as,
+ * per 4), we don't want a red root or two
+ * consecutive red nodes.
+ */
+ if(rb_is_black(parent))
+ break;
+
+ gparent = rb_red_parent(parent);
+
+ tmp = gparent->rb_right;
+ if (parent != tmp) { /* parent == gparent->rb_left */
+ if (tmp && rb_is_red(tmp)) {
+ /*
+ * Case 1 - node's uncle is red (color flips).
+ *
+ * G g
+ * / \ / \
+ * p u --> P U
+ * / /
+ * n n
+ *
+ * However, since g's parent might be red, and
+ * 4) does not allow this, we need to recurse
+ * at g.
+ */
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ rb_set_parent_color(parent, gparent, RB_BLACK);
+ node = gparent;
+ parent = rb_parent(node);
+ rb_set_parent_color(node, parent, RB_RED);
+ continue;
}
- if (parent->rb_right == node)
- {
- register struct rb_node *tmp;
- __rb_rotate_left(parent, root);
- tmp = parent;
+ tmp = parent->rb_right;
+ if (node == tmp) {
+ /*
+ * Case 2 - node's uncle is black and node is
+ * the parent's right child (left rotate at parent).
+ *
+ * G G
+ * / \ / \
+ * p U --> n U
+ * \ /
+ * n p
+ *
+ * This still leaves us in violation of 4), the
+ * continuation into Case 3 will fix that.
+ */
+ tmp = node->rb_left;
+ WRITE_ONCE(parent->rb_right, tmp);
+ WRITE_ONCE(node->rb_left, parent);
+ if (tmp)
+ rb_set_parent_color(tmp, parent,
+ RB_BLACK);
+ rb_set_parent_color(parent, node, RB_RED);
+ augment_rotate(parent, node);
parent = node;
- node = tmp;
+ tmp = node->rb_right;
}
- rb_set_black(parent);
- rb_set_red(gparent);
- __rb_rotate_right(gparent, root);
+ /*
+ * Case 3 - node's uncle is black and node is
+ * the parent's left child (right rotate at gparent).
+ *
+ * G P
+ * / \ / \
+ * p U --> n g
+ * / \
+ * n U
+ */
+ WRITE_ONCE(gparent->rb_left, tmp); /* == parent->rb_right */
+ WRITE_ONCE(parent->rb_right, gparent);
+ if (tmp)
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ __rb_rotate_set_parents(gparent, parent, root, RB_RED);
+ augment_rotate(gparent, parent);
+ break;
} else {
- {
- register struct rb_node *uncle = gparent->rb_left;
- if (uncle && rb_is_red(uncle))
- {
- rb_set_black(uncle);
- rb_set_black(parent);
- rb_set_red(gparent);
- node = gparent;
- continue;
- }
+ tmp = gparent->rb_left;
+ if (tmp && rb_is_red(tmp)) {
+ /* Case 1 - color flips */
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ rb_set_parent_color(parent, gparent, RB_BLACK);
+ node = gparent;
+ parent = rb_parent(node);
+ rb_set_parent_color(node, parent, RB_RED);
+ continue;
}
- if (parent->rb_left == node)
- {
- register struct rb_node *tmp;
- __rb_rotate_right(parent, root);
- tmp = parent;
+ tmp = parent->rb_left;
+ if (node == tmp) {
+ /* Case 2 - right rotate at parent */
+ tmp = node->rb_right;
+ WRITE_ONCE(parent->rb_left, tmp);
+ WRITE_ONCE(node->rb_right, parent);
+ if (tmp)
+ rb_set_parent_color(tmp, parent,
+ RB_BLACK);
+ rb_set_parent_color(parent, node, RB_RED);
+ augment_rotate(parent, node);
parent = node;
- node = tmp;
+ tmp = node->rb_left;
}
- rb_set_black(parent);
- rb_set_red(gparent);
- __rb_rotate_left(gparent, root);
+ /* Case 3 - left rotate at gparent */
+ WRITE_ONCE(gparent->rb_right, tmp); /* == parent->rb_left */
+ WRITE_ONCE(parent->rb_left, gparent);
+ if (tmp)
+ rb_set_parent_color(tmp, gparent, RB_BLACK);
+ __rb_rotate_set_parents(gparent, parent, root, RB_RED);
+ augment_rotate(gparent, parent);
+ break;
}
}
-
- rb_set_black(root->rb_node);
}
-static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
- struct rb_root *root)
+/*
+ * Inline version for rb_erase() use - we want to be able to inline
+ * and eliminate the dummy_rotate callback there
+ */
+static __always_inline void
+____rb_erase_color(struct rb_node *parent, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
- struct rb_node *other;
-
- while ((!node || rb_is_black(node)) && node != root->rb_node)
- {
- if (parent->rb_left == node)
- {
- other = parent->rb_right;
- if (rb_is_red(other))
- {
- rb_set_black(other);
- rb_set_red(parent);
- __rb_rotate_left(parent, root);
- other = parent->rb_right;
- }
- if ((!other->rb_left || rb_is_black(other->rb_left)) &&
- (!other->rb_right || rb_is_black(other->rb_right)))
- {
- rb_set_red(other);
- node = parent;
- parent = rb_parent(node);
+ struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
+
+ while (true) {
+ /*
+ * Loop invariants:
+ * - node is black (or NULL on first iteration)
+ * - node is not the root (parent is not NULL)
+ * - All leaf paths going through parent and node have a
+ * black node count that is 1 lower than other leaf paths.
+ */
+ sibling = parent->rb_right;
+ if (node != sibling) { /* node == parent->rb_left */
+ if (rb_is_red(sibling)) {
+ /*
+ * Case 1 - left rotate at parent
+ *
+ * P S
+ * / \ / \
+ * N s --> p Sr
+ * / \ / \
+ * Sl Sr N Sl
+ */
+ tmp1 = sibling->rb_left;
+ WRITE_ONCE(parent->rb_right, tmp1);
+ WRITE_ONCE(sibling->rb_left, parent);
+ rb_set_parent_color(tmp1, parent, RB_BLACK);
+ __rb_rotate_set_parents(parent, sibling, root,
+ RB_RED);
+ augment_rotate(parent, sibling);
+ sibling = tmp1;
}
- else
- {
- if (!other->rb_right || rb_is_black(other->rb_right))
- {
- rb_set_black(other->rb_left);
- rb_set_red(other);
- __rb_rotate_right(other, root);
- other = parent->rb_right;
+ tmp1 = sibling->rb_right;
+ if (!tmp1 || rb_is_black(tmp1)) {
+ tmp2 = sibling->rb_left;
+ if (!tmp2 || rb_is_black(tmp2)) {
+ /*
+ * Case 2 - sibling color flip
+ * (p could be either color here)
+ *
+ * (p) (p)
+ * / \ / \
+ * N S --> N s
+ * / \ / \
+ * Sl Sr Sl Sr
+ *
+ * This leaves us violating 5) which
+ * can be fixed by flipping p to black
+ * if it was red, or by recursing at p.
+ * p is red when coming from Case 1.
+ */
+ rb_set_parent_color(sibling, parent,
+ RB_RED);
+ if (rb_is_red(parent))
+ rb_set_black(parent);
+ else {
+ node = parent;
+ parent = rb_parent(node);
+ if (parent)
+ continue;
+ }
+ break;
}
- rb_set_color(other, rb_color(parent));
- rb_set_black(parent);
- rb_set_black(other->rb_right);
- __rb_rotate_left(parent, root);
- node = root->rb_node;
- break;
+ /*
+ * Case 3 - right rotate at sibling
+ * (p could be either color here)
+ *
+ * (p) (p)
+ * / \ / \
+ * N S --> N sl
+ * / \ \
+ * sl Sr S
+ * \
+ * Sr
+ *
+ * Note: p might be red, and then both
+ * p and sl are red after rotation(which
+ * breaks property 4). This is fixed in
+ * Case 4 (in __rb_rotate_set_parents()
+ * which set sl the color of p
+ * and set p RB_BLACK)
+ *
+ * (p) (sl)
+ * / \ / \
+ * N sl --> P S
+ * \ / \
+ * S N Sr
+ * \
+ * Sr
+ */
+ tmp1 = tmp2->rb_right;
+ WRITE_ONCE(sibling->rb_left, tmp1);
+ WRITE_ONCE(tmp2->rb_right, sibling);
+ WRITE_ONCE(parent->rb_right, tmp2);
+ if (tmp1)
+ rb_set_parent_color(tmp1, sibling,
+ RB_BLACK);
+ augment_rotate(sibling, tmp2);
+ tmp1 = sibling;
+ sibling = tmp2;
}
- }
- else
- {
- other = parent->rb_left;
- if (rb_is_red(other))
- {
- rb_set_black(other);
- rb_set_red(parent);
- __rb_rotate_right(parent, root);
- other = parent->rb_left;
- }
- if ((!other->rb_left || rb_is_black(other->rb_left)) &&
- (!other->rb_right || rb_is_black(other->rb_right)))
- {
- rb_set_red(other);
- node = parent;
- parent = rb_parent(node);
+ /*
+ * Case 4 - left rotate at parent + color flips
+ * (p and sl could be either color here.
+ * After rotation, p becomes black, s acquires
+ * p's color, and sl keeps its color)
+ *
+ * (p) (s)
+ * / \ / \
+ * N S --> P Sr
+ * / \ / \
+ * (sl) sr N (sl)
+ */
+ tmp2 = sibling->rb_left;
+ WRITE_ONCE(parent->rb_right, tmp2);
+ WRITE_ONCE(sibling->rb_left, parent);
+ rb_set_parent_color(tmp1, sibling, RB_BLACK);
+ if (tmp2)
+ rb_set_parent(tmp2, parent);
+ __rb_rotate_set_parents(parent, sibling, root,
+ RB_BLACK);
+ augment_rotate(parent, sibling);
+ break;
+ } else {
+ sibling = parent->rb_left;
+ if (rb_is_red(sibling)) {
+ /* Case 1 - right rotate at parent */
+ tmp1 = sibling->rb_right;
+ WRITE_ONCE(parent->rb_left, tmp1);
+ WRITE_ONCE(sibling->rb_right, parent);
+ rb_set_parent_color(tmp1, parent, RB_BLACK);
+ __rb_rotate_set_parents(parent, sibling, root,
+ RB_RED);
+ augment_rotate(parent, sibling);
+ sibling = tmp1;
}
- else
- {
- if (!other->rb_left || rb_is_black(other->rb_left))
- {
- rb_set_black(other->rb_right);
- rb_set_red(other);
- __rb_rotate_left(other, root);
- other = parent->rb_left;
+ tmp1 = sibling->rb_left;
+ if (!tmp1 || rb_is_black(tmp1)) {
+ tmp2 = sibling->rb_right;
+ if (!tmp2 || rb_is_black(tmp2)) {
+ /* Case 2 - sibling color flip */
+ rb_set_parent_color(sibling, parent,
+ RB_RED);
+ if (rb_is_red(parent))
+ rb_set_black(parent);
+ else {
+ node = parent;
+ parent = rb_parent(node);
+ if (parent)
+ continue;
+ }
+ break;
}
- rb_set_color(other, rb_color(parent));
- rb_set_black(parent);
- rb_set_black(other->rb_left);
- __rb_rotate_right(parent, root);
- node = root->rb_node;
- break;
+ /* Case 3 - left rotate at sibling */
+ tmp1 = tmp2->rb_left;
+ WRITE_ONCE(sibling->rb_right, tmp1);
+ WRITE_ONCE(tmp2->rb_left, sibling);
+ WRITE_ONCE(parent->rb_left, tmp2);
+ if (tmp1)
+ rb_set_parent_color(tmp1, sibling,
+ RB_BLACK);
+ augment_rotate(sibling, tmp2);
+ tmp1 = sibling;
+ sibling = tmp2;
}
+ /* Case 4 - right rotate at parent + color flips */
+ tmp2 = sibling->rb_right;
+ WRITE_ONCE(parent->rb_left, tmp2);
+ WRITE_ONCE(sibling->rb_right, parent);
+ rb_set_parent_color(tmp1, sibling, RB_BLACK);
+ if (tmp2)
+ rb_set_parent(tmp2, parent);
+ __rb_rotate_set_parents(parent, sibling, root,
+ RB_BLACK);
+ augment_rotate(parent, sibling);
+ break;
}
}
- if (node)
- rb_set_black(node);
}
-void rb_erase(struct rb_node *node, struct rb_root *root)
+/* Non-inline version for rb_erase_augmented() use */
+void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
- struct rb_node *child, *parent;
- int color;
+ ____rb_erase_color(parent, root, augment_rotate);
+}
- if (!node->rb_left)
- child = node->rb_right;
- else if (!node->rb_right)
- child = node->rb_left;
- else
- {
- struct rb_node *old = node, *left;
+/*
+ * Non-augmented rbtree manipulation functions.
+ *
+ * We use dummy augmented callbacks here, and have the compiler optimize them
+ * out of the rb_insert_color() and rb_erase() function definitions.
+ */
- node = node->rb_right;
- while ((left = node->rb_left) != NULL)
- node = left;
-
- if (rb_parent(old)) {
- if (rb_parent(old)->rb_left == old)
- rb_parent(old)->rb_left = node;
- else
- rb_parent(old)->rb_right = node;
- } else
- root->rb_node = node;
-
- child = node->rb_right;
- parent = rb_parent(node);
- color = rb_color(node);
-
- if (parent == old) {
- parent = node;
- } else {
- if (child)
- rb_set_parent(child, parent);
- parent->rb_left = child;
+static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
+static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {}
+static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {}
- node->rb_right = old->rb_right;
- rb_set_parent(old->rb_right, node);
- }
+static const struct rb_augment_callbacks dummy_callbacks = {
+ .propagate = dummy_propagate,
+ .copy = dummy_copy,
+ .rotate = dummy_rotate
+};
- node->rb_parent_color = old->rb_parent_color;
- node->rb_left = old->rb_left;
- rb_set_parent(old->rb_left, node);
+void rb_insert_color(struct rb_node *node, struct rb_root *root)
+{
+ __rb_insert(node, root, dummy_rotate);
+}
- goto color;
- }
+void rb_erase(struct rb_node *node, struct rb_root *root)
+{
+ struct rb_node *rebalance;
+ rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
+ if (rebalance)
+ ____rb_erase_color(rebalance, root, dummy_rotate);
+}
- parent = rb_parent(node);
- color = rb_color(node);
-
- if (child)
- rb_set_parent(child, parent);
- if (parent)
- {
- if (parent->rb_left == node)
- parent->rb_left = child;
- else
- parent->rb_right = child;
- }
- else
- root->rb_node = child;
+/*
+ * Augmented rbtree manipulation functions.
+ *
+ * This instantiates the same __always_inline functions as in the non-augmented
+ * case, but this time with user-defined callbacks.
+ */
- color:
- if (color == RB_BLACK)
- __rb_erase_color(child, parent, root);
+void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+{
+ __rb_insert(node, root, augment_rotate);
}
/*
@@ -312,24 +486,27 @@ struct rb_node *rb_next(const struct rb_node *node)
{
struct rb_node *parent;
- if (rb_parent(node) == node)
+ if (RB_EMPTY_NODE(node))
return NULL;
- /* If we have a right-hand child, go down and then left as far
- as we can. */
+ /*
+ * If we have a right-hand child, go down and then left as far
+ * as we can.
+ */
if (node->rb_right) {
- node = node->rb_right;
+ node = node->rb_right;
while (node->rb_left)
- node=node->rb_left;
+ node = node->rb_left;
return (struct rb_node *)node;
}
- /* No right-hand children. Everything down and left is
- smaller than us, so any 'next' node must be in the general
- direction of our parent. Go up the tree; any time the
- ancestor is a right-hand child of its parent, keep going
- up. First time it's a left-hand child of its parent, said
- parent is our 'next' node. */
+ /*
+ * No right-hand children. Everything down and left is smaller than us,
+ * so any 'next' node must be in the general direction of our parent.
+ * Go up the tree; any time the ancestor is a right-hand child of its
+ * parent, keep going up. First time it's a left-hand child of its
+ * parent, said parent is our 'next' node.
+ */
while ((parent = rb_parent(node)) && node == parent->rb_right)
node = parent;
@@ -340,20 +517,24 @@ struct rb_node *rb_prev(const struct rb_node *node)
{
struct rb_node *parent;
- if (rb_parent(node) == node)
+ if (RB_EMPTY_NODE(node))
return NULL;
- /* If we have a left-hand child, go down and then right as far
- as we can. */
+ /*
+ * If we have a left-hand child, go down and then right as far
+ * as we can.
+ */
if (node->rb_left) {
- node = node->rb_left;
+ node = node->rb_left;
while (node->rb_right)
- node=node->rb_right;
+ node = node->rb_right;
return (struct rb_node *)node;
}
- /* No left-hand children. Go up till we find an ancestor which
- is a right-hand child of its parent */
+ /*
+ * No left-hand children. Go up till we find an ancestor which
+ * is a right-hand child of its parent.
+ */
while ((parent = rb_parent(node)) && node == parent->rb_left)
node = parent;
@@ -365,20 +546,51 @@ void rb_replace_node(struct rb_node *victim, struct rb_node *new,
{
struct rb_node *parent = rb_parent(victim);
+ /* Copy the pointers/colour from the victim to the replacement */
+ *new = *victim;
+
/* Set the surrounding nodes to point to the replacement */
- if (parent) {
- if (victim == parent->rb_left)
- parent->rb_left = new;
- else
- parent->rb_right = new;
- } else {
- root->rb_node = new;
- }
if (victim->rb_left)
rb_set_parent(victim->rb_left, new);
if (victim->rb_right)
rb_set_parent(victim->rb_right, new);
+ __rb_change_child(victim, new, parent, root);
+}
- /* Copy the pointers/colour from the victim to the replacement */
- *new = *victim;
+static struct rb_node *rb_left_deepest_node(const struct rb_node *node)
+{
+ for (;;) {
+ if (node->rb_left)
+ node = node->rb_left;
+ else if (node->rb_right)
+ node = node->rb_right;
+ else
+ return (struct rb_node *)node;
+ }
+}
+
+struct rb_node *rb_next_postorder(const struct rb_node *node)
+{
+ const struct rb_node *parent;
+ if (!node)
+ return NULL;
+ parent = rb_parent(node);
+
+ /* If we're sitting on node, we've already seen our children */
+ if (parent && node == parent->rb_left && parent->rb_right) {
+ /* If we are the parent's left node, go to the parent's right
+ * node then all the way down to the left */
+ return rb_left_deepest_node(parent->rb_right);
+ } else
+ /* Otherwise we are the parent's right node, and the parent
+ * should be next */
+ return (struct rb_node *)parent;
+}
+
+struct rb_node *rb_first_postorder(const struct rb_root *root)
+{
+ if (!root->rb_node)
+ return NULL;
+
+ return rb_left_deepest_node(root->rb_node);
}
diff --git a/dlm_controld/rbtree.h b/dlm_controld/rbtree.h
index 9a4ad606..ddb86ff6 100644
--- a/dlm_controld/rbtree.h
+++ b/dlm_controld/rbtree.h
@@ -1,20 +1,8 @@
+/* Copied from linux/include/linux/rbtree.h */
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@suse.de>
- 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.
linux/include/linux/rbtree.h
@@ -23,138 +11,313 @@
I know it's not the cleaner way, but in C (not in C++) to get
performances and genericity...
- Some example of insert and search follows here. The search is a plain
- normal search over an ordered tree. The insert instead must be implemented
- int two steps: as first thing the code must insert the element in
- order as a red leaf in the tree, then the support library function
- rb_insert_color() must be called. Such function will do the
- not trivial work to rebalance the rbtree if necessary.
+ See Documentation/core-api/rbtree.rst for documentation and samples.
+*/
+
+#ifndef _LINUX_RBTREE_H
+#define _LINUX_RBTREE_H
+
+#include <stdbool.h>
+#include <string.h>
+
+#include "list.h"
+#include "rbtree_types.h"
+
+#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
+
+#define rb_entry(ptr, type, member) container_of(ptr, type, member)
+
+#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
+
+/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
+#define RB_EMPTY_NODE(node) \
+ ((node)->__rb_parent_color == (unsigned long)(node))
+#define RB_CLEAR_NODE(node) \
+ ((node)->__rb_parent_color = (unsigned long)(node))
+
+
+extern void rb_insert_color(struct rb_node *, struct rb_root *);
+extern void rb_erase(struct rb_node *, struct rb_root *);
+
+
+/* Find logical next and previous nodes in a tree */
+extern struct rb_node *rb_next(const struct rb_node *);
+extern struct rb_node *rb_prev(const struct rb_node *);
+extern struct rb_node *rb_first(const struct rb_root *);
+extern struct rb_node *rb_last(const struct rb_root *);
+
+/* Postorder iteration - always visit the parent after its children */
+extern struct rb_node *rb_first_postorder(const struct rb_root *);
+extern struct rb_node *rb_next_postorder(const struct rb_node *);
+
+/* Fast replacement of a single node without remove/rebalance/add/rebalance */
+extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
+ struct rb_root *root);
------------------------------------------------------------------------
-static inline struct page * rb_search_page_cache(struct inode * inode,
- unsigned long offset)
+static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
+ struct rb_node **rb_link)
{
- struct rb_node * n = inode->i_rb_page_cache.rb_node;
- struct page * page;
+ node->__rb_parent_color = (unsigned long)parent;
+ node->rb_left = node->rb_right = NULL;
- while (n)
- {
- page = rb_entry(n, struct page, rb_page_cache);
+ *rb_link = node;
+}
- if (offset < page->offset)
- n = n->rb_left;
- else if (offset > page->offset)
- n = n->rb_right;
- else
- return page;
- }
- return NULL;
+#define rb_entry_safe(ptr, type, member) \
+ ({ typeof(ptr) ____ptr = (ptr); \
+ ____ptr ? rb_entry(____ptr, type, member) : NULL; \
+ })
+
+/**
+ * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
+ * given type allowing the backing memory of @pos to be invalidated
+ *
+ * @pos: the 'type *' to use as a loop cursor.
+ * @n: another 'type *' to use as temporary storage
+ * @root: 'rb_root *' of the rbtree.
+ * @field: the name of the rb_node field within 'type'.
+ *
+ * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
+ * list_for_each_entry_safe() and allows the iteration to continue independent
+ * of changes to @pos by the body of the loop.
+ *
+ * Note, however, that it cannot handle other modifications that re-order the
+ * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
+ * rb_erase() may rebalance the tree, causing us to miss some nodes.
+ */
+#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
+ for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
+ pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
+ typeof(*pos), field); 1; }); \
+ pos = n)
+
+/* Same as rb_first(), but O(1) */
+#define rb_first_cached(root) (root)->rb_leftmost
+
+static inline void rb_insert_color_cached(struct rb_node *node,
+ struct rb_root_cached *root,
+ bool leftmost)
+{
+ if (leftmost)
+ root->rb_leftmost = node;
+ rb_insert_color(node, &root->rb_root);
}
-static inline struct page * __rb_insert_page_cache(struct inode * inode,
- unsigned long offset,
- struct rb_node * node)
+
+static inline struct rb_node *
+rb_erase_cached(struct rb_node *node, struct rb_root_cached *root)
{
- struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
- struct rb_node * parent = NULL;
- struct page * page;
-
- while (*p)
- {
- parent = *p;
- page = rb_entry(parent, struct page, rb_page_cache);
-
- if (offset < page->offset)
- p = &(*p)->rb_left;
- else if (offset > page->offset)
- p = &(*p)->rb_right;
- else
- return page;
- }
+ struct rb_node *leftmost = NULL;
- rb_link_node(node, parent, p);
+ if (root->rb_leftmost == node)
+ leftmost = root->rb_leftmost = rb_next(node);
- return NULL;
+ rb_erase(node, &root->rb_root);
+
+ return leftmost;
}
-static inline struct page * rb_insert_page_cache(struct inode * inode,
- unsigned long offset,
- struct rb_node * node)
+static inline void rb_replace_node_cached(struct rb_node *victim,
+ struct rb_node *new,
+ struct rb_root_cached *root)
{
- struct page * ret;
- if ((ret = __rb_insert_page_cache(inode, offset, node)))
- goto out;
- rb_insert_color(node, &inode->i_rb_page_cache);
- out:
- return ret;
+ if (root->rb_leftmost == victim)
+ root->rb_leftmost = new;
+ rb_replace_node(victim, new, &root->rb_root);
}
------------------------------------------------------------------------
-*/
-#ifndef _LINUX_RBTREE_H
-#define _LINUX_RBTREE_H
-
-#include <linux/stddef.h>
+/*
+ * The below helper functions use 2 operators with 3 different
+ * calling conventions. The operators are related like:
+ *
+ * comp(a->key,b) < 0 := less(a,b)
+ * comp(a->key,b) > 0 := less(b,a)
+ * comp(a->key,b) == 0 := !less(a,b) && !less(b,a)
+ *
+ * If these operators define a partial order on the elements we make no
+ * guarantee on which of the elements matching the key is found. See
+ * rb_find().
+ *
+ * The reason for this is to allow the find() interface without requiring an
+ * on-stack dummy object, which might not be feasible due to object size.
+ */
-struct rb_node
-{
- unsigned long rb_parent_color;
-#define RB_RED 0
-#define RB_BLACK 1
- struct rb_node *rb_right;
- struct rb_node *rb_left;
-} __attribute__((aligned(sizeof(long))));
- /* The alignment might seem pointless, but allegedly CRIS needs it */
-
-struct rb_root
+/**
+ * rb_add_cached() - insert @node into the leftmost cached tree @tree
+ * @node: node to insert
+ * @tree: leftmost cached tree to insert @node into
+ * @less: operator defining the (partial) node order
+ *
+ * Returns @node when it is the new leftmost, or NULL.
+ */
+static __always_inline struct rb_node *
+rb_add_cached(struct rb_node *node, struct rb_root_cached *tree,
+ bool (*less)(struct rb_node *, const struct rb_node *))
{
- struct rb_node *rb_node;
-};
+ struct rb_node **link = &tree->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ bool leftmost = true;
+ while (*link) {
+ parent = *link;
+ if (less(node, parent)) {
+ link = &parent->rb_left;
+ } else {
+ link = &parent->rb_right;
+ leftmost = false;
+ }
+ }
-#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
-#define rb_color(r) ((r)->rb_parent_color & 1)
-#define rb_is_red(r) (!rb_color(r))
-#define rb_is_black(r) rb_color(r)
-#define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
-#define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0)
+ rb_link_node(node, parent, link);
+ rb_insert_color_cached(node, tree, leftmost);
-static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
-{
- rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
+ return leftmost ? node : NULL;
}
-static inline void rb_set_color(struct rb_node *rb, int color)
+
+/**
+ * rb_add() - insert @node into @tree
+ * @node: node to insert
+ * @tree: tree to insert @node into
+ * @less: operator defining the (partial) node order
+ */
+static __always_inline void
+rb_add(struct rb_node *node, struct rb_root *tree,
+ bool (*less)(struct rb_node *, const struct rb_node *))
{
- rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
+ struct rb_node **link = &tree->rb_node;
+ struct rb_node *parent = NULL;
+
+ while (*link) {
+ parent = *link;
+ if (less(node, parent))
+ link = &parent->rb_left;
+ else
+ link = &parent->rb_right;
+ }
+
+ rb_link_node(node, parent, link);
+ rb_insert_color(node, tree);
}
-#define RB_ROOT (struct rb_root) { NULL, }
-#define rb_entry(ptr, type, member) container_of(ptr, type, member)
+/**
+ * rb_find_add() - find equivalent @node in @tree, or add @node
+ * @node: node to look-for / insert
+ * @tree: tree to search / modify
+ * @cmp: operator defining the node order
+ *
+ * Returns the rb_node matching @node, or NULL when no match is found and @node
+ * is inserted.
+ */
+static __always_inline struct rb_node *
+rb_find_add(struct rb_node *node, struct rb_root *tree,
+ int (*cmp)(struct rb_node *, const struct rb_node *))
+{
+ struct rb_node **link = &tree->rb_node;
+ struct rb_node *parent = NULL;
+ int c;
-#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
-#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
-#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
+ while (*link) {
+ parent = *link;
+ c = cmp(node, parent);
-extern void rb_insert_color(struct rb_node *, struct rb_root *);
-extern void rb_erase(struct rb_node *, struct rb_root *);
+ if (c < 0)
+ link = &parent->rb_left;
+ else if (c > 0)
+ link = &parent->rb_right;
+ else
+ return parent;
+ }
-/* Find logical next and previous nodes in a tree */
-extern struct rb_node *rb_next(const struct rb_node *);
-extern struct rb_node *rb_prev(const struct rb_node *);
-extern struct rb_node *rb_first(const struct rb_root *);
-extern struct rb_node *rb_last(const struct rb_root *);
+ rb_link_node(node, parent, link);
+ rb_insert_color(node, tree);
+ return NULL;
+}
-/* Fast replacement of a single node without remove/rebalance/add/rebalance */
-extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
- struct rb_root *root);
+/**
+ * rb_find() - find @key in tree @tree
+ * @key: key to match
+ * @tree: tree to search
+ * @cmp: operator defining the node order
+ *
+ * Returns the rb_node matching @key or NULL.
+ */
+static __always_inline struct rb_node *
+rb_find(const void *key, const struct rb_root *tree,
+ int (*cmp)(const void *key, const struct rb_node *))
+{
+ struct rb_node *node = tree->rb_node;
+
+ while (node) {
+ int c = cmp(key, node);
+
+ if (c < 0)
+ node = node->rb_left;
+ else if (c > 0)
+ node = node->rb_right;
+ else
+ return node;
+ }
+
+ return NULL;
+}
-static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
- struct rb_node ** rb_link)
+/**
+ * rb_find_first() - find the first @key in @tree
+ * @key: key to match
+ * @tree: tree to search
+ * @cmp: operator defining node order
+ *
+ * Returns the leftmost node matching @key, or NULL.
+ */
+static __always_inline struct rb_node *
+rb_find_first(const void *key, const struct rb_root *tree,
+ int (*cmp)(const void *key, const struct rb_node *))
{
- node->rb_parent_color = (unsigned long )parent;
- node->rb_left = node->rb_right = NULL;
+ struct rb_node *node = tree->rb_node;
+ struct rb_node *match = NULL;
- *rb_link = node;
+ while (node) {
+ int c = cmp(key, node);
+
+ if (c <= 0) {
+ if (!c)
+ match = node;
+ node = node->rb_left;
+ } else if (c > 0) {
+ node = node->rb_right;
+ }
+ }
+
+ return match;
}
+/**
+ * rb_next_match() - find the next @key in @tree
+ * @key: key to match
+ * @tree: tree to search
+ * @cmp: operator defining node order
+ *
+ * Returns the next node matching @key, or NULL.
+ */
+static __always_inline struct rb_node *
+rb_next_match(const void *key, struct rb_node *node,
+ int (*cmp)(const void *key, const struct rb_node *))
+{
+ node = rb_next(node);
+ if (node && cmp(key, node))
+ node = NULL;
+ return node;
+}
+
+/**
+ * rb_for_each() - iterates a subtree matching @key
+ * @node: iterator
+ * @key: key to match
+ * @tree: tree to search
+ * @cmp: operator defining node order
+ */
+#define rb_for_each(node, key, tree, cmp) \
+ for ((node) = rb_find_first((key), (tree), (cmp)); \
+ (node); (node) = rb_next_match((key), (node), (cmp)))
+
#endif /* _LINUX_RBTREE_H */
diff --git a/dlm_controld/rbtree_augmented.h b/dlm_controld/rbtree_augmented.h
new file mode 100644
index 00000000..580a4c56
--- /dev/null
+++ b/dlm_controld/rbtree_augmented.h
@@ -0,0 +1,303 @@
+/* Copied from linux/include/linux/rbtree_augmented.h */
+/*
+ Red Black Trees
+ (C) 1999 Andrea Arcangeli <andrea@suse.de>
+ (C) 2002 David Woodhouse <dwmw2@infradead.org>
+ (C) 2012 Michel Lespinasse <walken@google.com>
+
+
+ linux/include/linux/rbtree_augmented.h
+*/
+
+#ifndef _LINUX_RBTREE_AUGMENTED_H
+#define _LINUX_RBTREE_AUGMENTED_H
+
+#include "rbtree.h"
+#include "linux_helpers.h"
+
+/*
+ * Please note - only struct rb_augment_callbacks and the prototypes for
+ * rb_insert_augmented() and rb_erase_augmented() are intended to be public.
+ * The rest are implementation details you are not expected to depend on.
+ *
+ * See Documentation/core-api/rbtree.rst for documentation and samples.
+ */
+
+struct rb_augment_callbacks {
+ void (*propagate)(struct rb_node *node, struct rb_node *stop);
+ void (*copy)(struct rb_node *old, struct rb_node *new);
+ void (*rotate)(struct rb_node *old, struct rb_node *new);
+};
+
+extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
+
+/*
+ * Fixup the rbtree and update the augmented information when rebalancing.
+ *
+ * On insertion, the user must update the augmented information on the path
+ * leading to the inserted node, then call rb_link_node() as usual and
+ * rb_insert_augmented() instead of the usual rb_insert_color() call.
+ * If rb_insert_augmented() rebalances the rbtree, it will callback into
+ * a user provided function to update the augmented information on the
+ * affected subtrees.
+ */
+static inline void
+rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+ const struct rb_augment_callbacks *augment)
+{
+ __rb_insert_augmented(node, root, augment->rotate);
+}
+
+static inline void
+rb_insert_augmented_cached(struct rb_node *node,
+ struct rb_root_cached *root, bool newleft,
+ const struct rb_augment_callbacks *augment)
+{
+ if (newleft)
+ root->rb_leftmost = node;
+ rb_insert_augmented(node, &root->rb_root, augment);
+}
+
+/*
+ * Template for declaring augmented rbtree callbacks (generic case)
+ *
+ * RBSTATIC: 'static' or empty
+ * RBNAME: name of the rb_augment_callbacks structure
+ * RBSTRUCT: struct type of the tree nodes
+ * RBFIELD: name of struct rb_node field within RBSTRUCT
+ * RBAUGMENTED: name of field within RBSTRUCT holding data for subtree
+ * RBCOMPUTE: name of function that recomputes the RBAUGMENTED data
+ */
+
+#define RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \
+ RBSTRUCT, RBFIELD, RBAUGMENTED, RBCOMPUTE) \
+static inline void \
+RBNAME ## _propagate(struct rb_node *rb, struct rb_node *stop) \
+{ \
+ while (rb != stop) { \
+ RBSTRUCT *node = rb_entry(rb, RBSTRUCT, RBFIELD); \
+ if (RBCOMPUTE(node, true)) \
+ break; \
+ rb = rb_parent(&node->RBFIELD); \
+ } \
+} \
+static inline void \
+RBNAME ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
+{ \
+ RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
+ RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
+ new->RBAUGMENTED = old->RBAUGMENTED; \
+} \
+static void \
+RBNAME ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
+{ \
+ RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
+ RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
+ new->RBAUGMENTED = old->RBAUGMENTED; \
+ RBCOMPUTE(old, false); \
+} \
+RBSTATIC const struct rb_augment_callbacks RBNAME = { \
+ .propagate = RBNAME ## _propagate, \
+ .copy = RBNAME ## _copy, \
+ .rotate = RBNAME ## _rotate \
+};
+
+/*
+ * Template for declaring augmented rbtree callbacks,
+ * computing RBAUGMENTED scalar as max(RBCOMPUTE(node)) for all subtree nodes.
+ *
+ * RBSTATIC: 'static' or empty
+ * RBNAME: name of the rb_augment_callbacks structure
+ * RBSTRUCT: struct type of the tree nodes
+ * RBFIELD: name of struct rb_node field within RBSTRUCT
+ * RBTYPE: type of the RBAUGMENTED field
+ * RBAUGMENTED: name of RBTYPE field within RBSTRUCT holding data for subtree
+ * RBCOMPUTE: name of function that returns the per-node RBTYPE scalar
+ */
+
+#define RB_DECLARE_CALLBACKS_MAX(RBSTATIC, RBNAME, RBSTRUCT, RBFIELD, \
+ RBTYPE, RBAUGMENTED, RBCOMPUTE) \
+static inline bool RBNAME ## _compute_max(RBSTRUCT *node, bool exit) \
+{ \
+ RBSTRUCT *child; \
+ RBTYPE max = RBCOMPUTE(node); \
+ if (node->RBFIELD.rb_left) { \
+ child = rb_entry(node->RBFIELD.rb_left, RBSTRUCT, RBFIELD); \
+ if (child->RBAUGMENTED > max) \
+ max = child->RBAUGMENTED; \
+ } \
+ if (node->RBFIELD.rb_right) { \
+ child = rb_entry(node->RBFIELD.rb_right, RBSTRUCT, RBFIELD); \
+ if (child->RBAUGMENTED > max) \
+ max = child->RBAUGMENTED; \
+ } \
+ if (exit && node->RBAUGMENTED == max) \
+ return true; \
+ node->RBAUGMENTED = max; \
+ return false; \
+} \
+RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \
+ RBSTRUCT, RBFIELD, RBAUGMENTED, RBNAME ## _compute_max)
+
+
+#define RB_RED 0
+#define RB_BLACK 1
+
+#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
+
+#define __rb_color(pc) ((pc) & 1)
+#define __rb_is_black(pc) __rb_color(pc)
+#define __rb_is_red(pc) (!__rb_color(pc))
+#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
+#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
+#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
+
+static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
+{
+ rb->__rb_parent_color = rb_color(rb) + (unsigned long)p;
+}
+
+static inline void rb_set_parent_color(struct rb_node *rb,
+ struct rb_node *p, int color)
+{
+ rb->__rb_parent_color = (unsigned long)p + color;
+}
+
+static inline void
+__rb_change_child(struct rb_node *old, struct rb_node *new,
+ struct rb_node *parent, struct rb_root *root)
+{
+ if (parent) {
+ if (parent->rb_left == old)
+ WRITE_ONCE(parent->rb_left, new);
+ else
+ WRITE_ONCE(parent->rb_right, new);
+ } else
+ WRITE_ONCE(root->rb_node, new);
+}
+
+extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
+
+static __always_inline struct rb_node *
+__rb_erase_augmented(struct rb_node *node, struct rb_root *root,
+ const struct rb_augment_callbacks *augment)
+{
+ struct rb_node *child = node->rb_right;
+ struct rb_node *tmp = node->rb_left;
+ struct rb_node *parent, *rebalance;
+ unsigned long pc;
+
+ if (!tmp) {
+ /*
+ * Case 1: node to erase has no more than 1 child (easy!)
+ *
+ * Note that if there is one child it must be red due to 5)
+ * and node must be black due to 4). We adjust colors locally
+ * so as to bypass __rb_erase_color() later on.
+ */
+ pc = node->__rb_parent_color;
+ parent = __rb_parent(pc);
+ __rb_change_child(node, child, parent, root);
+ if (child) {
+ child->__rb_parent_color = pc;
+ rebalance = NULL;
+ } else
+ rebalance = __rb_is_black(pc) ? parent : NULL;
+ tmp = parent;
+ } else if (!child) {
+ /* Still case 1, but this time the child is node->rb_left */
+ tmp->__rb_parent_color = pc = node->__rb_parent_color;
+ parent = __rb_parent(pc);
+ __rb_change_child(node, tmp, parent, root);
+ rebalance = NULL;
+ tmp = parent;
+ } else {
+ struct rb_node *successor = child, *child2;
+
+ tmp = child->rb_left;
+ if (!tmp) {
+ /*
+ * Case 2: node's successor is its right child
+ *
+ * (n) (s)
+ * / \ / \
+ * (x) (s) -> (x) (c)
+ * \
+ * (c)
+ */
+ parent = successor;
+ child2 = successor->rb_right;
+
+ augment->copy(node, successor);
+ } else {
+ /*
+ * Case 3: node's successor is leftmost under
+ * node's right child subtree
+ *
+ * (n) (s)
+ * / \ / \
+ * (x) (y) -> (x) (y)
+ * / /
+ * (p) (p)
+ * / /
+ * (s) (c)
+ * \
+ * (c)
+ */
+ do {
+ parent = successor;
+ successor = tmp;
+ tmp = tmp->rb_left;
+ } while (tmp);
+ child2 = successor->rb_right;
+ WRITE_ONCE(parent->rb_left, child2);
+ WRITE_ONCE(successor->rb_right, child);
+ rb_set_parent(child, successor);
+
+ augment->copy(node, successor);
+ augment->propagate(parent, successor);
+ }
+
+ tmp = node->rb_left;
+ WRITE_ONCE(successor->rb_left, tmp);
+ rb_set_parent(tmp, successor);
+
+ pc = node->__rb_parent_color;
+ tmp = __rb_parent(pc);
+ __rb_change_child(node, successor, tmp, root);
+
+ if (child2) {
+ rb_set_parent_color(child2, parent, RB_BLACK);
+ rebalance = NULL;
+ } else {
+ rebalance = rb_is_black(successor) ? parent : NULL;
+ }
+ successor->__rb_parent_color = pc;
+ tmp = successor;
+ }
+
+ augment->propagate(tmp, NULL);
+ return rebalance;
+}
+
+static __always_inline void
+rb_erase_augmented(struct rb_node *node, struct rb_root *root,
+ const struct rb_augment_callbacks *augment)
+{
+ struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
+ if (rebalance)
+ __rb_erase_color(rebalance, root, augment->rotate);
+}
+
+static __always_inline void
+rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root,
+ const struct rb_augment_callbacks *augment)
+{
+ if (root->rb_leftmost == node)
+ root->rb_leftmost = rb_next(node);
+ rb_erase_augmented(node, &root->rb_root, augment);
+}
+
+#endif /* _LINUX_RBTREE_AUGMENTED_H */
diff --git a/dlm_controld/rbtree_types.h b/dlm_controld/rbtree_types.h
new file mode 100644
index 00000000..d6ed9045
--- /dev/null
+++ b/dlm_controld/rbtree_types.h
@@ -0,0 +1,34 @@
+/* Copied from linux/include/linux/rbtree_types.h */
+#ifndef _LINUX_RBTREE_TYPES_H
+#define _LINUX_RBTREE_TYPES_H
+
+struct rb_node {
+ unsigned long __rb_parent_color;
+ struct rb_node *rb_right;
+ struct rb_node *rb_left;
+} __attribute__((aligned(sizeof(long))));
+/* The alignment might seem pointless, but allegedly CRIS needs it */
+
+struct rb_root {
+ struct rb_node *rb_node;
+};
+
+/*
+ * Leftmost-cached rbtrees.
+ *
+ * We do not cache the rightmost node based on footprint
+ * size vs number of potential users that could benefit
+ * from O(1) rb_last(). Just not worth it, users that want
+ * this feature can always implement the logic explicitly.
+ * Furthermore, users that want to cache both pointers may
+ * find it a bit asymmetric, but that's ok.
+ */
+struct rb_root_cached {
+ struct rb_root rb_root;
+ struct rb_node *rb_leftmost;
+};
+
+#define RB_ROOT (struct rb_root) { NULL, }
+#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
+
+#endif
--
2.31.1
next reply other threads:[~2023-08-21 16:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-21 16:25 Alexander Aring [this message]
2023-08-21 16:25 ` [Cluster-devel] [PATCH dlm-tool 2/3] dlm_controld: update container_of() implementation Alexander Aring
2023-08-21 16:25 ` [Cluster-devel] [PATCH dlm-tool 3/3] dlm_controld: update list implementation Alexander Aring
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