fs/bcachefs/bkey_cmp.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_BKEY_CMP_H
   3 #define _BCACHEFS_BKEY_CMP_H
   4
   5 #include "bkey.h"
   6
   7 #ifdef CONFIG_X86_64
   8 static inline int __bkey_cmp_bits(const u64 *l, const u64 *r,
   9                                   unsigned nr_key_bits)
  10 {
  11         long d0, d1, d2, d3;
  12         int cmp;
  13
  14         /* we shouldn't need asm for this, but gcc is being retarded: */
  15
  16         asm(".intel_syntax noprefix;"
  17             "xor eax, eax;"
  18             "xor edx, edx;"
  19             "1:;"
  20             "mov r8, [rdi];"
  21             "mov r9, [rsi];"
  22             "sub ecx, 64;"
  23             "jl 2f;"
  24
  25             "cmp r8, r9;"
  26             "jnz 3f;"
  27
  28             "lea rdi, [rdi - 8];"
  29             "lea rsi, [rsi - 8];"
  30             "jmp 1b;"
  31
  32             "2:;"
  33             "not ecx;"
  34             "shr r8, 1;"
  35             "shr r9, 1;"
  36             "shr r8, cl;"
  37             "shr r9, cl;"
  38             "cmp r8, r9;"
  39
  40             "3:\n"
  41             "seta al;"
  42             "setb dl;"
  43             "sub eax, edx;"
  44             ".att_syntax prefix;"
  45             : "=&D" (d0), "=&S" (d1), "=&d" (d2), "=&c" (d3), "=&a" (cmp)
  46             : "0" (l), "1" (r), "3" (nr_key_bits)
  47             : "r8", "r9", "cc", "memory");
  48
  49         return cmp;
  50 }
  51 #else
  52 static inline int __bkey_cmp_bits(const u64 *l, const u64 *r,
  53                                   unsigned nr_key_bits)
  54 {
  55         u64 l_v, r_v;
  56
  57         if (!nr_key_bits)
  58                 return 0;
  59
  60         /* for big endian, skip past header */
  61         nr_key_bits += high_bit_offset;
  62         l_v = *l & (~0ULL >> high_bit_offset);
  63         r_v = *r & (~0ULL >> high_bit_offset);
  64
  65         while (1) {
  66                 if (nr_key_bits < 64) {
  67                         l_v >>= 64 - nr_key_bits;
  68                         r_v >>= 64 - nr_key_bits;
  69                         nr_key_bits = 0;
  70                 } else {
  71                         nr_key_bits -= 64;
  72                 }
  73
  74                 if (!nr_key_bits || l_v != r_v)
  75                         break;
  76
  77                 l = next_word(l);
  78                 r = next_word(r);
  79
  80                 l_v = *l;
  81                 r_v = *r;
  82         }
  83
  84         return cmp_int(l_v, r_v);
  85 }
  86 #endif
  87
  88 static inline __pure __flatten
  89 int __bch2_bkey_cmp_packed_format_checked_inlined(const struct bkey_packed *l,
  90                                           const struct bkey_packed *r,
  91                                           const struct btree *b)
  92 {
  93         const struct bkey_format *f = &b->format;
  94         int ret;
  95
  96         EBUG_ON(!bkey_packed(l) || !bkey_packed(r));
  97         EBUG_ON(b->nr_key_bits != bkey_format_key_bits(f));
  98
  99         ret = __bkey_cmp_bits(high_word(f, l),
 100                               high_word(f, r),
 101                               b->nr_key_bits);
 102
 103         EBUG_ON(ret != bpos_cmp(bkey_unpack_pos(b, l),
 104                                 bkey_unpack_pos(b, r)));
 105         return ret;
 106 }
 107
 108 static inline __pure __flatten
 109 int bch2_bkey_cmp_packed_inlined(const struct btree *b,
 110                          const struct bkey_packed *l,
 111                          const struct bkey_packed *r)
 112 {
 113         struct bkey unpacked;
 114
 115         if (likely(bkey_packed(l) && bkey_packed(r)))
 116                 return __bch2_bkey_cmp_packed_format_checked_inlined(l, r, b);
 117
 118         if (bkey_packed(l)) {
 119                 __bkey_unpack_key_format_checked(b, &unpacked, l);
 120                 l = (void *) &unpacked;
 121         } else if (bkey_packed(r)) {
 122                 __bkey_unpack_key_format_checked(b, &unpacked, r);
 123                 r = (void *) &unpacked;
 124         }
 125
 126         return bpos_cmp(((struct bkey *) l)->p, ((struct bkey *) r)->p);
 127 }
 128
 129 #endif /* _BCACHEFS_BKEY_CMP_H */