![William Roberts](/assets/img/avatar_default.png)
When count is 0 and the highbit is not zero, the ebitmap is not valid and the internal node is not allocated. This causes issues when routines, like mls_context_isvalid() attempt to use the ebitmap_for_each_bit() and ebitmap_node_get_bit() as they assume a highbit > 0 will have a node allocated. Signed-off-by: William Roberts <william.c.roberts@intel.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
522 lines
10 KiB
C
522 lines
10 KiB
C
/*
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* Implementation of the extensible bitmap type.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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/*
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* Updated: Hewlett-Packard <paul@paul-moore.com>
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*
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* Added support to import/export the NetLabel category bitmap
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*
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* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
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*/
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/*
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* Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
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* Applied standard bit operations to improve bitmap scanning.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <net/netlabel.h>
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#include "ebitmap.h"
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#include "policydb.h"
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#define BITS_PER_U64 (sizeof(u64) * 8)
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int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
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{
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struct ebitmap_node *n1, *n2;
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if (e1->highbit != e2->highbit)
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return 0;
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n1 = e1->node;
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n2 = e2->node;
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while (n1 && n2 &&
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(n1->startbit == n2->startbit) &&
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!memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
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n1 = n1->next;
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n2 = n2->next;
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}
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if (n1 || n2)
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return 0;
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return 1;
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}
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int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src)
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{
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struct ebitmap_node *n, *new, *prev;
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ebitmap_init(dst);
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n = src->node;
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prev = NULL;
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while (n) {
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new = kzalloc(sizeof(*new), GFP_ATOMIC);
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if (!new) {
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ebitmap_destroy(dst);
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return -ENOMEM;
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}
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new->startbit = n->startbit;
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memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
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new->next = NULL;
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if (prev)
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prev->next = new;
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else
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dst->node = new;
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prev = new;
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n = n->next;
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}
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dst->highbit = src->highbit;
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return 0;
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}
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#ifdef CONFIG_NETLABEL
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/**
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* ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
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* @ebmap: the ebitmap to export
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* @catmap: the NetLabel category bitmap
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*
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* Description:
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* Export a SELinux extensibile bitmap into a NetLabel category bitmap.
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* Returns zero on success, negative values on error.
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*
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*/
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int ebitmap_netlbl_export(struct ebitmap *ebmap,
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struct netlbl_lsm_catmap **catmap)
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{
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struct ebitmap_node *e_iter = ebmap->node;
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unsigned long e_map;
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u32 offset;
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unsigned int iter;
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int rc;
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if (e_iter == NULL) {
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*catmap = NULL;
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return 0;
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}
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if (*catmap != NULL)
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netlbl_catmap_free(*catmap);
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*catmap = NULL;
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while (e_iter) {
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offset = e_iter->startbit;
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for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
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e_map = e_iter->maps[iter];
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if (e_map != 0) {
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rc = netlbl_catmap_setlong(catmap,
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offset,
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e_map,
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GFP_ATOMIC);
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if (rc != 0)
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goto netlbl_export_failure;
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}
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offset += EBITMAP_UNIT_SIZE;
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}
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e_iter = e_iter->next;
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}
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return 0;
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netlbl_export_failure:
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netlbl_catmap_free(*catmap);
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return -ENOMEM;
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}
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/**
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* ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
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* @ebmap: the ebitmap to import
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* @catmap: the NetLabel category bitmap
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*
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* Description:
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* Import a NetLabel category bitmap into a SELinux extensibile bitmap.
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* Returns zero on success, negative values on error.
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*
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*/
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int ebitmap_netlbl_import(struct ebitmap *ebmap,
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struct netlbl_lsm_catmap *catmap)
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{
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int rc;
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struct ebitmap_node *e_iter = NULL;
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struct ebitmap_node *e_prev = NULL;
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u32 offset = 0, idx;
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unsigned long bitmap;
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for (;;) {
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rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
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if (rc < 0)
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goto netlbl_import_failure;
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if (offset == (u32)-1)
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return 0;
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/* don't waste ebitmap space if the netlabel bitmap is empty */
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if (bitmap == 0) {
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offset += EBITMAP_UNIT_SIZE;
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continue;
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}
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if (e_iter == NULL ||
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offset >= e_iter->startbit + EBITMAP_SIZE) {
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e_prev = e_iter;
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e_iter = kzalloc(sizeof(*e_iter), GFP_ATOMIC);
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if (e_iter == NULL)
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goto netlbl_import_failure;
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e_iter->startbit = offset - (offset % EBITMAP_SIZE);
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if (e_prev == NULL)
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ebmap->node = e_iter;
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else
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e_prev->next = e_iter;
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ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
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}
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/* offset will always be aligned to an unsigned long */
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idx = EBITMAP_NODE_INDEX(e_iter, offset);
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e_iter->maps[idx] = bitmap;
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/* next */
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offset += EBITMAP_UNIT_SIZE;
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}
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/* NOTE: we should never reach this return */
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return 0;
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netlbl_import_failure:
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ebitmap_destroy(ebmap);
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return -ENOMEM;
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}
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#endif /* CONFIG_NETLABEL */
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/*
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* Check to see if all the bits set in e2 are also set in e1. Optionally,
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* if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
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* last_e2bit.
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*/
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int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit)
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{
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struct ebitmap_node *n1, *n2;
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int i;
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if (e1->highbit < e2->highbit)
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return 0;
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n1 = e1->node;
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n2 = e2->node;
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while (n1 && n2 && (n1->startbit <= n2->startbit)) {
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if (n1->startbit < n2->startbit) {
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n1 = n1->next;
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continue;
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}
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for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
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i--; /* Skip trailing NULL map entries */
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if (last_e2bit && (i >= 0)) {
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u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
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__fls(n2->maps[i]);
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if (lastsetbit > last_e2bit)
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return 0;
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}
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while (i >= 0) {
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if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
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return 0;
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i--;
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}
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n1 = n1->next;
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n2 = n2->next;
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}
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if (n2)
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return 0;
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return 1;
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}
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int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
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{
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struct ebitmap_node *n;
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if (e->highbit < bit)
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return 0;
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n = e->node;
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while (n && (n->startbit <= bit)) {
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if ((n->startbit + EBITMAP_SIZE) > bit)
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return ebitmap_node_get_bit(n, bit);
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n = n->next;
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}
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return 0;
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}
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int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
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{
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struct ebitmap_node *n, *prev, *new;
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prev = NULL;
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n = e->node;
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while (n && n->startbit <= bit) {
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if ((n->startbit + EBITMAP_SIZE) > bit) {
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if (value) {
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ebitmap_node_set_bit(n, bit);
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} else {
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unsigned int s;
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ebitmap_node_clr_bit(n, bit);
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s = find_first_bit(n->maps, EBITMAP_SIZE);
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if (s < EBITMAP_SIZE)
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return 0;
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/* drop this node from the bitmap */
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if (!n->next) {
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/*
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* this was the highest map
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* within the bitmap
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*/
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if (prev)
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e->highbit = prev->startbit
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+ EBITMAP_SIZE;
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else
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e->highbit = 0;
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}
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if (prev)
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prev->next = n->next;
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else
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e->node = n->next;
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kfree(n);
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}
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return 0;
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}
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prev = n;
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n = n->next;
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}
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if (!value)
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return 0;
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new = kzalloc(sizeof(*new), GFP_ATOMIC);
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if (!new)
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return -ENOMEM;
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new->startbit = bit - (bit % EBITMAP_SIZE);
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ebitmap_node_set_bit(new, bit);
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if (!n)
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/* this node will be the highest map within the bitmap */
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e->highbit = new->startbit + EBITMAP_SIZE;
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if (prev) {
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new->next = prev->next;
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prev->next = new;
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} else {
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new->next = e->node;
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e->node = new;
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}
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return 0;
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}
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void ebitmap_destroy(struct ebitmap *e)
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{
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struct ebitmap_node *n, *temp;
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if (!e)
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return;
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n = e->node;
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while (n) {
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temp = n;
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n = n->next;
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kfree(temp);
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}
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e->highbit = 0;
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e->node = NULL;
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return;
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}
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int ebitmap_read(struct ebitmap *e, void *fp)
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{
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struct ebitmap_node *n = NULL;
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u32 mapunit, count, startbit, index;
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u64 map;
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__le32 buf[3];
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int rc, i;
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ebitmap_init(e);
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rc = next_entry(buf, fp, sizeof buf);
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if (rc < 0)
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goto out;
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mapunit = le32_to_cpu(buf[0]);
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e->highbit = le32_to_cpu(buf[1]);
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count = le32_to_cpu(buf[2]);
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if (mapunit != BITS_PER_U64) {
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printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
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"match my size %Zd (high bit was %d)\n",
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mapunit, BITS_PER_U64, e->highbit);
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goto bad;
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}
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/* round up e->highbit */
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e->highbit += EBITMAP_SIZE - 1;
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e->highbit -= (e->highbit % EBITMAP_SIZE);
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if (!e->highbit) {
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e->node = NULL;
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goto ok;
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}
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if (e->highbit && !count)
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goto bad;
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for (i = 0; i < count; i++) {
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rc = next_entry(&startbit, fp, sizeof(u32));
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if (rc < 0) {
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printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
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goto bad;
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}
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startbit = le32_to_cpu(startbit);
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if (startbit & (mapunit - 1)) {
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printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
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"not a multiple of the map unit size (%u)\n",
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startbit, mapunit);
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goto bad;
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}
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if (startbit > e->highbit - mapunit) {
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printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
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"beyond the end of the bitmap (%u)\n",
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startbit, (e->highbit - mapunit));
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goto bad;
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}
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if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
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struct ebitmap_node *tmp;
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tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
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if (!tmp) {
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printk(KERN_ERR
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"SELinux: ebitmap: out of memory\n");
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rc = -ENOMEM;
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goto bad;
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}
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/* round down */
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tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
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if (n)
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n->next = tmp;
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else
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e->node = tmp;
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n = tmp;
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} else if (startbit <= n->startbit) {
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printk(KERN_ERR "SELinux: ebitmap: start bit %d"
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" comes after start bit %d\n",
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startbit, n->startbit);
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goto bad;
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}
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rc = next_entry(&map, fp, sizeof(u64));
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if (rc < 0) {
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printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
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goto bad;
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}
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map = le64_to_cpu(map);
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index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
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while (map) {
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n->maps[index++] = map & (-1UL);
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map = EBITMAP_SHIFT_UNIT_SIZE(map);
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}
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}
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ok:
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rc = 0;
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out:
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return rc;
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bad:
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if (!rc)
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rc = -EINVAL;
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ebitmap_destroy(e);
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goto out;
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}
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int ebitmap_write(struct ebitmap *e, void *fp)
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{
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struct ebitmap_node *n;
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u32 count;
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__le32 buf[3];
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u64 map;
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int bit, last_bit, last_startbit, rc;
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buf[0] = cpu_to_le32(BITS_PER_U64);
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count = 0;
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last_bit = 0;
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last_startbit = -1;
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ebitmap_for_each_positive_bit(e, n, bit) {
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if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
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count++;
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last_startbit = rounddown(bit, BITS_PER_U64);
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}
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last_bit = roundup(bit + 1, BITS_PER_U64);
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}
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buf[1] = cpu_to_le32(last_bit);
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buf[2] = cpu_to_le32(count);
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rc = put_entry(buf, sizeof(u32), 3, fp);
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if (rc)
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return rc;
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map = 0;
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last_startbit = INT_MIN;
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ebitmap_for_each_positive_bit(e, n, bit) {
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if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
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__le64 buf64[1];
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/* this is the very first bit */
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if (!map) {
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last_startbit = rounddown(bit, BITS_PER_U64);
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map = (u64)1 << (bit - last_startbit);
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continue;
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}
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/* write the last node */
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buf[0] = cpu_to_le32(last_startbit);
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rc = put_entry(buf, sizeof(u32), 1, fp);
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if (rc)
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return rc;
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buf64[0] = cpu_to_le64(map);
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rc = put_entry(buf64, sizeof(u64), 1, fp);
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if (rc)
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return rc;
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/* set up for the next node */
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map = 0;
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last_startbit = rounddown(bit, BITS_PER_U64);
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}
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map |= (u64)1 << (bit - last_startbit);
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}
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/* write the last node */
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if (map) {
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__le64 buf64[1];
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/* write the last node */
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buf[0] = cpu_to_le32(last_startbit);
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rc = put_entry(buf, sizeof(u32), 1, fp);
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if (rc)
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return rc;
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buf64[0] = cpu_to_le64(map);
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rc = put_entry(buf64, sizeof(u64), 1, fp);
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if (rc)
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return rc;
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}
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return 0;
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}
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