forked from Minki/linux
9fe79ad1e4
* We add ebitmap_for_each_positive_bit() which enables to walk on
any positive bit on the given ebitmap, to improve its performance
using common bit-operations defined in linux/bitops.h.
In the previous version, this logic was implemented using a combination
of ebitmap_for_each_bit() and ebitmap_node_get_bit(), but is was worse
in performance aspect.
This logic is most frequestly used to compute a new AVC entry,
so this patch can improve SELinux performance when AVC misses are happen.
* struct ebitmap_node is redefined as an array of "unsigned long", to get
suitable for using find_next_bit() which is fasted than iteration of
shift and logical operation, and to maximize memory usage allocated
from general purpose slab.
* Any ebitmap_for_each_bit() are repleced by the new implementation
in ss/service.c and ss/mls.c. Some of related implementation are
changed, however, there is no incompatibility with the previous
version.
* The width of any new line are less or equal than 80-chars.
The following benchmark shows the effect of this patch, when we
access many files which have different security context one after
another. The number is more than /selinux/avc/cache_threshold, so
any access always causes AVC misses.
selinux-2.6 selinux-2.6-ebitmap
AVG: 22.763 [s] 8.750 [s]
STD: 0.265 0.019
------------------------------------------
1st: 22.558 [s] 8.786 [s]
2nd: 22.458 [s] 8.750 [s]
3rd: 22.478 [s] 8.754 [s]
4th: 22.724 [s] 8.745 [s]
5th: 22.918 [s] 8.748 [s]
6th: 22.905 [s] 8.764 [s]
7th: 23.238 [s] 8.726 [s]
8th: 22.822 [s] 8.729 [s]
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
144 lines
4.0 KiB
C
144 lines
4.0 KiB
C
/*
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* An extensible bitmap is a bitmap that supports an
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* arbitrary number of bits. Extensible bitmaps are
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* used to represent sets of values, such as types,
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* roles, categories, and classes.
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*
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* Each extensible bitmap is implemented as a linked
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* list of bitmap nodes, where each bitmap node has
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* an explicitly specified starting bit position within
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* the total bitmap.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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#ifndef _SS_EBITMAP_H_
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#define _SS_EBITMAP_H_
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#include <net/netlabel.h>
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#define EBITMAP_UNIT_NUMS ((32 - sizeof(void *) - sizeof(u32)) \
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/ sizeof(unsigned long))
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#define EBITMAP_UNIT_SIZE BITS_PER_LONG
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#define EBITMAP_SIZE (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
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#define EBITMAP_BIT 1ULL
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struct ebitmap_node {
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struct ebitmap_node *next;
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unsigned long maps[EBITMAP_UNIT_NUMS];
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u32 startbit;
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};
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struct ebitmap {
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struct ebitmap_node *node; /* first node in the bitmap */
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u32 highbit; /* highest position in the total bitmap */
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};
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#define ebitmap_length(e) ((e)->highbit)
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#define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
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static inline unsigned int ebitmap_start_positive(struct ebitmap *e,
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struct ebitmap_node **n)
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{
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unsigned int ofs;
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for (*n = e->node; *n; *n = (*n)->next) {
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ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
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if (ofs < EBITMAP_SIZE)
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return (*n)->startbit + ofs;
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}
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return ebitmap_length(e);
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}
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static inline void ebitmap_init(struct ebitmap *e)
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{
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memset(e, 0, sizeof(*e));
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}
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static inline unsigned int ebitmap_next_positive(struct ebitmap *e,
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struct ebitmap_node **n,
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unsigned int bit)
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{
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unsigned int ofs;
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ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
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if (ofs < EBITMAP_SIZE)
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return ofs + (*n)->startbit;
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for (*n = (*n)->next; *n; *n = (*n)->next) {
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ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
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if (ofs < EBITMAP_SIZE)
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return ofs + (*n)->startbit;
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}
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return ebitmap_length(e);
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}
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#define EBITMAP_NODE_INDEX(node, bit) \
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(((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
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#define EBITMAP_NODE_OFFSET(node, bit) \
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(((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
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static inline int ebitmap_node_get_bit(struct ebitmap_node *n,
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unsigned int bit)
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{
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unsigned int index = EBITMAP_NODE_INDEX(n, bit);
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unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
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BUG_ON(index >= EBITMAP_UNIT_NUMS);
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if ((n->maps[index] & (EBITMAP_BIT << ofs)))
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return 1;
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return 0;
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}
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static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
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unsigned int bit)
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{
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unsigned int index = EBITMAP_NODE_INDEX(n, bit);
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unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
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BUG_ON(index >= EBITMAP_UNIT_NUMS);
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n->maps[index] |= (EBITMAP_BIT << ofs);
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}
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static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
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unsigned int bit)
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{
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unsigned int index = EBITMAP_NODE_INDEX(n, bit);
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unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
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BUG_ON(index >= EBITMAP_UNIT_NUMS);
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n->maps[index] &= ~(EBITMAP_BIT << ofs);
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}
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#define ebitmap_for_each_positive_bit(e, n, bit) \
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for (bit = ebitmap_start_positive(e, &n); \
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bit < ebitmap_length(e); \
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bit = ebitmap_next_positive(e, &n, bit)) \
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int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
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int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
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int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
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int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
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int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
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void ebitmap_destroy(struct ebitmap *e);
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int ebitmap_read(struct ebitmap *e, void *fp);
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#ifdef CONFIG_NETLABEL
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int ebitmap_netlbl_export(struct ebitmap *ebmap,
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struct netlbl_lsm_secattr_catmap **catmap);
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int ebitmap_netlbl_import(struct ebitmap *ebmap,
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struct netlbl_lsm_secattr_catmap *catmap);
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#else
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static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
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struct netlbl_lsm_secattr_catmap **catmap)
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{
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return -ENOMEM;
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}
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static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
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struct netlbl_lsm_secattr_catmap *catmap)
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{
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return -ENOMEM;
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}
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#endif
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#endif /* _SS_EBITMAP_H_ */
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