1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
8 #include <linux/blkdev.h>
9 #include <linux/buffer_head.h>
11 #include <linux/nls.h>
17 #define BITS_IN_SIZE_T (sizeof(size_t) * 8)
20 * fill_mask[i] - first i bits are '1' , i = 0,1,2,3,4,5,6,7,8
21 * fill_mask[i] = 0xFF >> (8-i)
23 static const u8 fill_mask[] = { 0x00, 0x01, 0x03, 0x07, 0x0F,
24 0x1F, 0x3F, 0x7F, 0xFF };
27 * zero_mask[i] - first i bits are '0' , i = 0,1,2,3,4,5,6,7,8
28 * zero_mask[i] = 0xFF << i
30 static const u8 zero_mask[] = { 0xFF, 0xFE, 0xFC, 0xF8, 0xF0,
31 0xE0, 0xC0, 0x80, 0x00 };
36 * Return: True if all bits [bit, bit+nbits) are zeros "0".
38 bool are_bits_clear(const ulong *lmap, size_t bit, size_t nbits)
41 const u8 *map = (u8 *)lmap + (bit >> 3);
45 return !nbits || !(*map & fill_mask[pos + nbits] &
48 if (*map++ & zero_mask[pos])
53 pos = ((size_t)map) & (sizeof(size_t) - 1);
55 pos = sizeof(size_t) - pos;
56 if (nbits >= pos * 8) {
57 for (nbits -= pos * 8; pos; pos--, map++) {
64 for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
69 for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
75 if (pos && (*map & fill_mask[pos]))
84 * Return: True if all bits [bit, bit+nbits) are ones "1".
86 bool are_bits_set(const ulong *lmap, size_t bit, size_t nbits)
90 const u8 *map = (u8 *)lmap + (bit >> 3);
93 if (8 - pos >= nbits) {
94 mask = fill_mask[pos + nbits] & zero_mask[pos];
95 return !nbits || (*map & mask) == mask;
98 mask = zero_mask[pos];
99 if ((*map++ & mask) != mask)
104 pos = ((size_t)map) & (sizeof(size_t) - 1);
106 pos = sizeof(size_t) - pos;
107 if (nbits >= pos * 8) {
108 for (nbits -= pos * 8; pos; pos--, map++) {
115 for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
116 if (*((size_t *)map) != MINUS_ONE_T)
120 for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
127 u8 mask = fill_mask[pos];
129 if ((*map & mask) != mask)