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1 | #include <linux/compiler.h> |
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2 | #include <linux/types.h> |
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3 | #include <asm/intrinsics.h> |
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4 | #include <linux/module.h> |
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5 | #include <linux/bitops.h> |
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6 | |
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7 | /* |
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8 | * Find next zero bit in a bitmap reasonably efficiently.. |
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9 | */ |
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10 | |
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11 | int __find_next_zero_bit (const void *addr, unsigned long size, unsigned long offset) |
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12 | { |
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13 | unsigned long *p = ((unsigned long *) addr) + (offset >> 6); |
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14 | unsigned long result = offset & ~63UL; |
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15 | unsigned long tmp; |
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16 | |
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17 | if (offset >= size) |
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18 | return size; |
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19 | size -= result; |
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20 | offset &= 63UL; |
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21 | if (offset) { |
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22 | tmp = *(p++); |
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23 | tmp |= ~0UL >> (64-offset); |
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24 | if (size < 64) |
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25 | goto found_first; |
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26 | if (~tmp) |
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27 | goto found_middle; |
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28 | size -= 64; |
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29 | result += 64; |
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30 | } |
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31 | while (size & ~63UL) { |
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32 | if (~(tmp = *(p++))) |
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33 | goto found_middle; |
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34 | result += 64; |
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35 | size -= 64; |
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36 | } |
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37 | if (!size) |
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38 | return result; |
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39 | tmp = *p; |
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40 | found_first: |
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41 | tmp |= ~0UL << size; |
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42 | if (tmp == ~0UL) /* any bits zero? */ |
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43 | return result + size; /* nope */ |
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44 | found_middle: |
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45 | return result + ffz(tmp); |
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46 | } |
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47 | EXPORT_SYMBOL(__find_next_zero_bit); |
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48 | |
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49 | /* |
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50 | * Find next bit in a bitmap reasonably efficiently.. |
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51 | */ |
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52 | int __find_next_bit(const void *addr, unsigned long size, unsigned long offset) |
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53 | { |
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54 | unsigned long *p = ((unsigned long *) addr) + (offset >> 6); |
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55 | unsigned long result = offset & ~63UL; |
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56 | unsigned long tmp; |
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57 | |
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58 | if (offset >= size) |
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59 | return size; |
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60 | size -= result; |
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61 | offset &= 63UL; |
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62 | if (offset) { |
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63 | tmp = *(p++); |
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64 | tmp &= ~0UL << offset; |
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65 | if (size < 64) |
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66 | goto found_first; |
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67 | if (tmp) |
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68 | goto found_middle; |
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69 | size -= 64; |
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70 | result += 64; |
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71 | } |
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72 | while (size & ~63UL) { |
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73 | if ((tmp = *(p++))) |
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74 | goto found_middle; |
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75 | result += 64; |
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76 | size -= 64; |
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77 | } |
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78 | if (!size) |
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79 | return result; |
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80 | tmp = *p; |
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81 | found_first: |
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82 | tmp &= ~0UL >> (64-size); |
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83 | if (tmp == 0UL) /* Are any bits set? */ |
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84 | return result + size; /* Nope. */ |
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85 | found_middle: |
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86 | return result + __ffs(tmp); |
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87 | } |
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88 | EXPORT_SYMBOL(__find_next_bit); |
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