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a767f680e3
Currently, the ebitmap_node structure has a fixed size of 32 bytes. On a 32-bit system, the overhead is 8 bytes, leaving 24 bytes for being used as bitmaps. The overhead ratio is 1/4. On a 64-bit system, the overhead is 16 bytes. Therefore, only 16 bytes are left for bitmap purpose and the overhead ratio is 1/2. With a 3.8.2 kernel, a boot-up operation will cause the ebitmap_get_bit() function to be called about 9 million times. The average number of ebitmap_node traversal is about 3.7. This patch increases the size of the ebitmap_node structure to 64 bytes for 64-bit system to keep the overhead ratio at 1/4. This may also improve performance a little bit by making node to node traversal less frequent (< 2) as more bits are available in each node. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
152 lines
4.2 KiB
C
152 lines
4.2 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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#ifdef CONFIG_64BIT
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#define EBITMAP_NODE_SIZE 64
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#else
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#define EBITMAP_NODE_SIZE 32
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#endif
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#define EBITMAP_UNIT_NUMS ((EBITMAP_NODE_SIZE-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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#define EBITMAP_SHIFT_UNIT_SIZE(x) \
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(((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
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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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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, u32 last_e2bit);
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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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int ebitmap_write(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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