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haproxy/ebtree/eb32tree.h
Willy Tarreau 41136de58e BUILD: ebtree: improve architecture-specific alignment 
Commit 2c315ee75e ("BUG/MEDIUM: ebtree: don't set attribute packed
without unaligned access support") addressed alignment issues in
ebtrees in a way that is not really optimal since it will leave holes
in eb32trees for example.

This fix is better in that it restores the packed attribute on ebnode
but enforces proper alignment on the carrying nodes where necessary.
This also has the benefit of closing holes wherever possible and to
align data to the minimally required size.

The only thing it cannot close is the 32-bit hole at the end of ebmbnode
due to the required 64-bit on certain archs but at least it guarantees
that the key correctly points to the end of the node and that there is
never a hole after it.

This is a better fix than the one above and should be backported to
branches where the one above will be backported.
2020-02-25 10:34:49 +01:00

501 lines
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/*
* Elastic Binary Trees - macros and structures for operations on 32bit nodes.
* Version 6.0.6
* (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _EB32TREE_H
#define _EB32TREE_H
#include "ebtree.h"
/* Return the structure of type <type> whose member <member> points to <ptr> */
#define eb32_entry(ptr, type, member) container_of(ptr, type, member)
#define EB32_ROOT EB_ROOT
#define EB32_TREE_HEAD EB_TREE_HEAD
/* These types may sometimes already be defined */
typedef unsigned int u32;
typedef signed int s32;
/* This structure carries a node, a leaf, and a key. It must start with the
* eb_node so that it can be cast into an eb_node. We could also have put some
* sort of transparent union here to reduce the indirection level, but the fact
* is, the end user is not meant to manipulate internals, so this is pointless.
*/
struct eb32_node {
struct eb_node node; /* the tree node, must be at the beginning */
MAYBE_ALIGN(sizeof(u32));
u32 key;
} ALIGNED(sizeof(void*));
/*
* Exported functions and macros.
* Many of them are always inlined because they are extremely small, and
* are generally called at most once or twice in a program.
*/
/* Return leftmost node in the tree, or NULL if none */
static inline struct eb32_node *eb32_first(struct eb_root *root)
{
return eb32_entry(eb_first(root), struct eb32_node, node);
}
/* Return rightmost node in the tree, or NULL if none */
static inline struct eb32_node *eb32_last(struct eb_root *root)
{
return eb32_entry(eb_last(root), struct eb32_node, node);
}
/* Return next node in the tree, or NULL if none */
static inline struct eb32_node *eb32_next(struct eb32_node *eb32)
{
return eb32_entry(eb_next(&eb32->node), struct eb32_node, node);
}
/* Return previous node in the tree, or NULL if none */
static inline struct eb32_node *eb32_prev(struct eb32_node *eb32)
{
return eb32_entry(eb_prev(&eb32->node), struct eb32_node, node);
}
/* Return next leaf node within a duplicate sub-tree, or NULL if none. */
static inline struct eb32_node *eb32_next_dup(struct eb32_node *eb32)
{
return eb32_entry(eb_next_dup(&eb32->node), struct eb32_node, node);
}
/* Return previous leaf node within a duplicate sub-tree, or NULL if none. */
static inline struct eb32_node *eb32_prev_dup(struct eb32_node *eb32)
{
return eb32_entry(eb_prev_dup(&eb32->node), struct eb32_node, node);
}
/* Return next node in the tree, skipping duplicates, or NULL if none */
static inline struct eb32_node *eb32_next_unique(struct eb32_node *eb32)
{
return eb32_entry(eb_next_unique(&eb32->node), struct eb32_node, node);
}
/* Return previous node in the tree, skipping duplicates, or NULL if none */
static inline struct eb32_node *eb32_prev_unique(struct eb32_node *eb32)
{
return eb32_entry(eb_prev_unique(&eb32->node), struct eb32_node, node);
}
/* Delete node from the tree if it was linked in. Mark the node unused. Note
* that this function relies on a non-inlined generic function: eb_delete.
*/
static inline void eb32_delete(struct eb32_node *eb32)
{
eb_delete(&eb32->node);
}
/*
* The following functions are not inlined by default. They are declared
* in eb32tree.c, which simply relies on their inline version.
*/
struct eb32_node *eb32_lookup(struct eb_root *root, u32 x);
struct eb32_node *eb32i_lookup(struct eb_root *root, s32 x);
struct eb32_node *eb32_lookup_le(struct eb_root *root, u32 x);
struct eb32_node *eb32_lookup_ge(struct eb_root *root, u32 x);
struct eb32_node *eb32_insert(struct eb_root *root, struct eb32_node *new);
struct eb32_node *eb32i_insert(struct eb_root *root, struct eb32_node *new);
/*
* The following functions are less likely to be used directly, because their
* code is larger. The non-inlined version is preferred.
*/
/* Delete node from the tree if it was linked in. Mark the node unused. */
static forceinline void __eb32_delete(struct eb32_node *eb32)
{
__eb_delete(&eb32->node);
}
/*
* Find the first occurrence of a key in the tree <root>. If none can be
* found, return NULL.
*/
static forceinline struct eb32_node *__eb32_lookup(struct eb_root *root, u32 x)
{
struct eb32_node *node;
eb_troot_t *troot;
u32 y;
int node_bit;
troot = root->b[EB_LEFT];
if (unlikely(troot == NULL))
return NULL;
while (1) {
if ((eb_gettag(troot) == EB_LEAF)) {
node = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
if (node->key == x)
return node;
else
return NULL;
}
node = container_of(eb_untag(troot, EB_NODE),
struct eb32_node, node.branches);
node_bit = node->node.bit;
y = node->key ^ x;
if (!y) {
/* Either we found the node which holds the key, or
* we have a dup tree. In the later case, we have to
* walk it down left to get the first entry.
*/
if (node_bit < 0) {
troot = node->node.branches.b[EB_LEFT];
while (eb_gettag(troot) != EB_LEAF)
troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
node = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
}
return node;
}
if ((y >> node_bit) >= EB_NODE_BRANCHES)
return NULL; /* no more common bits */
troot = node->node.branches.b[(x >> node_bit) & EB_NODE_BRANCH_MASK];
}
}
/*
* Find the first occurrence of a signed key in the tree <root>. If none can
* be found, return NULL.
*/
static forceinline struct eb32_node *__eb32i_lookup(struct eb_root *root, s32 x)
{
struct eb32_node *node;
eb_troot_t *troot;
u32 key = x ^ 0x80000000;
u32 y;
int node_bit;
troot = root->b[EB_LEFT];
if (unlikely(troot == NULL))
return NULL;
while (1) {
if ((eb_gettag(troot) == EB_LEAF)) {
node = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
if (node->key == (u32)x)
return node;
else
return NULL;
}
node = container_of(eb_untag(troot, EB_NODE),
struct eb32_node, node.branches);
node_bit = node->node.bit;
y = node->key ^ x;
if (!y) {
/* Either we found the node which holds the key, or
* we have a dup tree. In the later case, we have to
* walk it down left to get the first entry.
*/
if (node_bit < 0) {
troot = node->node.branches.b[EB_LEFT];
while (eb_gettag(troot) != EB_LEAF)
troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
node = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
}
return node;
}
if ((y >> node_bit) >= EB_NODE_BRANCHES)
return NULL; /* no more common bits */
troot = node->node.branches.b[(key >> node_bit) & EB_NODE_BRANCH_MASK];
}
}
/* Insert eb32_node <new> into subtree starting at node root <root>.
* Only new->key needs be set with the key. The eb32_node is returned.
* If root->b[EB_RGHT]==1, the tree may only contain unique keys.
*/
static forceinline struct eb32_node *
__eb32_insert(struct eb_root *root, struct eb32_node *new) {
struct eb32_node *old;
unsigned int side;
eb_troot_t *troot, **up_ptr;
u32 newkey; /* caching the key saves approximately one cycle */
eb_troot_t *root_right;
eb_troot_t *new_left, *new_rght;
eb_troot_t *new_leaf;
int old_node_bit;
side = EB_LEFT;
troot = root->b[EB_LEFT];
root_right = root->b[EB_RGHT];
if (unlikely(troot == NULL)) {
/* Tree is empty, insert the leaf part below the left branch */
root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
new->node.leaf_p = eb_dotag(root, EB_LEFT);
new->node.node_p = NULL; /* node part unused */
return new;
}
/* The tree descent is fairly easy :
* - first, check if we have reached a leaf node
* - second, check if we have gone too far
* - third, reiterate
* Everywhere, we use <new> for the node node we are inserting, <root>
* for the node we attach it to, and <old> for the node we are
* displacing below <new>. <troot> will always point to the future node
* (tagged with its type). <side> carries the side the node <new> is
* attached to below its parent, which is also where previous node
* was attached. <newkey> carries the key being inserted.
*/
newkey = new->key;
while (1) {
if (eb_gettag(troot) == EB_LEAF) {
/* insert above a leaf */
old = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
new->node.node_p = old->node.leaf_p;
up_ptr = &old->node.leaf_p;
break;
}
/* OK we're walking down this link */
old = container_of(eb_untag(troot, EB_NODE),
struct eb32_node, node.branches);
old_node_bit = old->node.bit;
/* Stop going down when we don't have common bits anymore. We
* also stop in front of a duplicates tree because it means we
* have to insert above.
*/
if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
/* The tree did not contain the key, so we insert <new> before the node
* <old>, and set ->bit to designate the lowest bit position in <new>
* which applies to ->branches.b[].
*/
new->node.node_p = old->node.node_p;
up_ptr = &old->node.node_p;
break;
}
/* walk down */
root = &old->node.branches;
side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
troot = root->b[side];
}
new_left = eb_dotag(&new->node.branches, EB_LEFT);
new_rght = eb_dotag(&new->node.branches, EB_RGHT);
new_leaf = eb_dotag(&new->node.branches, EB_LEAF);
/* We need the common higher bits between new->key and old->key.
* What differences are there between new->key and the node here ?
* NOTE that bit(new) is always < bit(root) because highest
* bit of new->key and old->key are identical here (otherwise they
* would sit on different branches).
*/
// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;
if (new->key == old->key) {
new->node.bit = -1; /* mark as new dup tree, just in case */
if (likely(eb_gettag(root_right))) {
/* we refuse to duplicate this key if the tree is
* tagged as containing only unique keys.
*/
return old;
}
if (eb_gettag(troot) != EB_LEAF) {
/* there was already a dup tree below */
struct eb_node *ret;
ret = eb_insert_dup(&old->node, &new->node);
return container_of(ret, struct eb32_node, node);
}
/* otherwise fall through */
}
if (new->key >= old->key) {
new->node.branches.b[EB_LEFT] = troot;
new->node.branches.b[EB_RGHT] = new_leaf;
new->node.leaf_p = new_rght;
*up_ptr = new_left;
}
else {
new->node.branches.b[EB_LEFT] = new_leaf;
new->node.branches.b[EB_RGHT] = troot;
new->node.leaf_p = new_left;
*up_ptr = new_rght;
}
/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
* parent is already set to <new>, and the <root>'s branch is still in
* <side>. Update the root's leaf till we have it. Note that we can also
* find the side by checking the side of new->node.node_p.
*/
root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
return new;
}
/* Insert eb32_node <new> into subtree starting at node root <root>, using
* signed keys. Only new->key needs be set with the key. The eb32_node
* is returned. If root->b[EB_RGHT]==1, the tree may only contain unique keys.
*/
static forceinline struct eb32_node *
__eb32i_insert(struct eb_root *root, struct eb32_node *new) {
struct eb32_node *old;
unsigned int side;
eb_troot_t *troot, **up_ptr;
int newkey; /* caching the key saves approximately one cycle */
eb_troot_t *root_right;
eb_troot_t *new_left, *new_rght;
eb_troot_t *new_leaf;
int old_node_bit;
side = EB_LEFT;
troot = root->b[EB_LEFT];
root_right = root->b[EB_RGHT];
if (unlikely(troot == NULL)) {
/* Tree is empty, insert the leaf part below the left branch */
root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
new->node.leaf_p = eb_dotag(root, EB_LEFT);
new->node.node_p = NULL; /* node part unused */
return new;
}
/* The tree descent is fairly easy :
* - first, check if we have reached a leaf node
* - second, check if we have gone too far
* - third, reiterate
* Everywhere, we use <new> for the node node we are inserting, <root>
* for the node we attach it to, and <old> for the node we are
* displacing below <new>. <troot> will always point to the future node
* (tagged with its type). <side> carries the side the node <new> is
* attached to below its parent, which is also where previous node
* was attached. <newkey> carries a high bit shift of the key being
* inserted in order to have negative keys stored before positive
* ones.
*/
newkey = new->key + 0x80000000;
while (1) {
if (eb_gettag(troot) == EB_LEAF) {
old = container_of(eb_untag(troot, EB_LEAF),
struct eb32_node, node.branches);
new->node.node_p = old->node.leaf_p;
up_ptr = &old->node.leaf_p;
break;
}
/* OK we're walking down this link */
old = container_of(eb_untag(troot, EB_NODE),
struct eb32_node, node.branches);
old_node_bit = old->node.bit;
/* Stop going down when we don't have common bits anymore. We
* also stop in front of a duplicates tree because it means we
* have to insert above.
*/
if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
/* The tree did not contain the key, so we insert <new> before the node
* <old>, and set ->bit to designate the lowest bit position in <new>
* which applies to ->branches.b[].
*/
new->node.node_p = old->node.node_p;
up_ptr = &old->node.node_p;
break;
}
/* walk down */
root = &old->node.branches;
side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
troot = root->b[side];
}
new_left = eb_dotag(&new->node.branches, EB_LEFT);
new_rght = eb_dotag(&new->node.branches, EB_RGHT);
new_leaf = eb_dotag(&new->node.branches, EB_LEAF);
/* We need the common higher bits between new->key and old->key.
* What differences are there between new->key and the node here ?
* NOTE that bit(new) is always < bit(root) because highest
* bit of new->key and old->key are identical here (otherwise they
* would sit on different branches).
*/
// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;
if (new->key == old->key) {
new->node.bit = -1; /* mark as new dup tree, just in case */
if (likely(eb_gettag(root_right))) {
/* we refuse to duplicate this key if the tree is
* tagged as containing only unique keys.
*/
return old;
}
if (eb_gettag(troot) != EB_LEAF) {
/* there was already a dup tree below */
struct eb_node *ret;
ret = eb_insert_dup(&old->node, &new->node);
return container_of(ret, struct eb32_node, node);
}
/* otherwise fall through */
}
if ((s32)new->key >= (s32)old->key) {
new->node.branches.b[EB_LEFT] = troot;
new->node.branches.b[EB_RGHT] = new_leaf;
new->node.leaf_p = new_rght;
*up_ptr = new_left;
}
else {
new->node.branches.b[EB_LEFT] = new_leaf;
new->node.branches.b[EB_RGHT] = troot;
new->node.leaf_p = new_left;
*up_ptr = new_rght;
}
/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
* parent is already set to <new>, and the <root>'s branch is still in
* <side>. Update the root's leaf till we have it. Note that we can also
* find the side by checking the side of new->node.node_p.
*/
root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
return new;
}
#endif /* _EB32_TREE_H */
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