cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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drbd_interval.c (4160B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <asm/bug.h>
      3#include <linux/rbtree_augmented.h>
      4#include "drbd_interval.h"
      5
      6/*
      7 * interval_end  -  return end of @node
      8 */
      9static inline
     10sector_t interval_end(struct rb_node *node)
     11{
     12	struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
     13	return this->end;
     14}
     15
     16#define NODE_END(node) ((node)->sector + ((node)->size >> 9))
     17
     18RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
     19			 struct drbd_interval, rb, sector_t, end, NODE_END);
     20
     21/*
     22 * drbd_insert_interval  -  insert a new interval into a tree
     23 */
     24bool
     25drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
     26{
     27	struct rb_node **new = &root->rb_node, *parent = NULL;
     28	sector_t this_end = this->sector + (this->size >> 9);
     29
     30	BUG_ON(!IS_ALIGNED(this->size, 512));
     31
     32	while (*new) {
     33		struct drbd_interval *here =
     34			rb_entry(*new, struct drbd_interval, rb);
     35
     36		parent = *new;
     37		if (here->end < this_end)
     38			here->end = this_end;
     39		if (this->sector < here->sector)
     40			new = &(*new)->rb_left;
     41		else if (this->sector > here->sector)
     42			new = &(*new)->rb_right;
     43		else if (this < here)
     44			new = &(*new)->rb_left;
     45		else if (this > here)
     46			new = &(*new)->rb_right;
     47		else
     48			return false;
     49	}
     50
     51	this->end = this_end;
     52	rb_link_node(&this->rb, parent, new);
     53	rb_insert_augmented(&this->rb, root, &augment_callbacks);
     54	return true;
     55}
     56
     57/**
     58 * drbd_contains_interval  -  check if a tree contains a given interval
     59 * @root:	red black tree root
     60 * @sector:	start sector of @interval
     61 * @interval:	may not be a valid pointer
     62 *
     63 * Returns if the tree contains the node @interval with start sector @start.
     64 * Does not dereference @interval until @interval is known to be a valid object
     65 * in @tree.  Returns %false if @interval is in the tree but with a different
     66 * sector number.
     67 */
     68bool
     69drbd_contains_interval(struct rb_root *root, sector_t sector,
     70		       struct drbd_interval *interval)
     71{
     72	struct rb_node *node = root->rb_node;
     73
     74	while (node) {
     75		struct drbd_interval *here =
     76			rb_entry(node, struct drbd_interval, rb);
     77
     78		if (sector < here->sector)
     79			node = node->rb_left;
     80		else if (sector > here->sector)
     81			node = node->rb_right;
     82		else if (interval < here)
     83			node = node->rb_left;
     84		else if (interval > here)
     85			node = node->rb_right;
     86		else
     87			return true;
     88	}
     89	return false;
     90}
     91
     92/*
     93 * drbd_remove_interval  -  remove an interval from a tree
     94 */
     95void
     96drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
     97{
     98	rb_erase_augmented(&this->rb, root, &augment_callbacks);
     99}
    100
    101/**
    102 * drbd_find_overlap  - search for an interval overlapping with [sector, sector + size)
    103 * @root:	red black tree root
    104 * @sector:	start sector
    105 * @size:	size, aligned to 512 bytes
    106 *
    107 * Returns an interval overlapping with [sector, sector + size), or NULL if
    108 * there is none.  When there is more than one overlapping interval in the
    109 * tree, the interval with the lowest start sector is returned, and all other
    110 * overlapping intervals will be on the right side of the tree, reachable with
    111 * rb_next().
    112 */
    113struct drbd_interval *
    114drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
    115{
    116	struct rb_node *node = root->rb_node;
    117	struct drbd_interval *overlap = NULL;
    118	sector_t end = sector + (size >> 9);
    119
    120	BUG_ON(!IS_ALIGNED(size, 512));
    121
    122	while (node) {
    123		struct drbd_interval *here =
    124			rb_entry(node, struct drbd_interval, rb);
    125
    126		if (node->rb_left &&
    127		    sector < interval_end(node->rb_left)) {
    128			/* Overlap if any must be on left side */
    129			node = node->rb_left;
    130		} else if (here->sector < end &&
    131			   sector < here->sector + (here->size >> 9)) {
    132			overlap = here;
    133			break;
    134		} else if (sector >= here->sector) {
    135			/* Overlap if any must be on right side */
    136			node = node->rb_right;
    137		} else
    138			break;
    139	}
    140	return overlap;
    141}
    142
    143struct drbd_interval *
    144drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
    145{
    146	sector_t end = sector + (size >> 9);
    147	struct rb_node *node;
    148
    149	for (;;) {
    150		node = rb_next(&i->rb);
    151		if (!node)
    152			return NULL;
    153		i = rb_entry(node, struct drbd_interval, rb);
    154		if (i->sector >= end)
    155			return NULL;
    156		if (sector < i->sector + (i->size >> 9))
    157			return i;
    158	}
    159}