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-rw-r--r--drivers/md/dm-vdo/murmurhash3.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/murmurhash3.c b/drivers/md/dm-vdo/murmurhash3.c
new file mode 100644
index 0000000000..3a989efae1
--- /dev/null
+++ b/drivers/md/dm-vdo/murmurhash3.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: LGPL-2.1+
+/*
+ * MurmurHash3 was written by Austin Appleby, and is placed in the public
+ * domain. The author hereby disclaims copyright to this source code.
+ *
+ * Adapted by John Wiele (jwiele@redhat.com).
+ */
+
+#include "murmurhash3.h"
+
+#include <asm/unaligned.h>
+
+static inline u64 rotl64(u64 x, s8 r)
+{
+ return (x << r) | (x >> (64 - r));
+}
+
+#define ROTL64(x, y) rotl64(x, y)
+
+/* Finalization mix - force all bits of a hash block to avalanche */
+
+static __always_inline u64 fmix64(u64 k)
+{
+ k ^= k >> 33;
+ k *= 0xff51afd7ed558ccdLLU;
+ k ^= k >> 33;
+ k *= 0xc4ceb9fe1a85ec53LLU;
+ k ^= k >> 33;
+
+ return k;
+}
+
+void murmurhash3_128(const void *key, const int len, const u32 seed, void *out)
+{
+ const u8 *data = key;
+ const int nblocks = len / 16;
+
+ u64 h1 = seed;
+ u64 h2 = seed;
+
+ const u64 c1 = 0x87c37b91114253d5LLU;
+ const u64 c2 = 0x4cf5ad432745937fLLU;
+
+ u64 *hash_out = out;
+
+ /* body */
+
+ const u64 *blocks = (const u64 *)(data);
+
+ int i;
+
+ for (i = 0; i < nblocks; i++) {
+ u64 k1 = get_unaligned_le64(&blocks[i * 2]);
+ u64 k2 = get_unaligned_le64(&blocks[i * 2 + 1]);
+
+ k1 *= c1;
+ k1 = ROTL64(k1, 31);
+ k1 *= c2;
+ h1 ^= k1;
+
+ h1 = ROTL64(h1, 27);
+ h1 += h2;
+ h1 = h1 * 5 + 0x52dce729;
+
+ k2 *= c2;
+ k2 = ROTL64(k2, 33);
+ k2 *= c1;
+ h2 ^= k2;
+
+ h2 = ROTL64(h2, 31);
+ h2 += h1;
+ h2 = h2 * 5 + 0x38495ab5;
+ }
+
+ /* tail */
+
+ {
+ const u8 *tail = (const u8 *)(data + nblocks * 16);
+
+ u64 k1 = 0;
+ u64 k2 = 0;
+
+ switch (len & 15) {
+ case 15:
+ k2 ^= ((u64)tail[14]) << 48;
+ fallthrough;
+ case 14:
+ k2 ^= ((u64)tail[13]) << 40;
+ fallthrough;
+ case 13:
+ k2 ^= ((u64)tail[12]) << 32;
+ fallthrough;
+ case 12:
+ k2 ^= ((u64)tail[11]) << 24;
+ fallthrough;
+ case 11:
+ k2 ^= ((u64)tail[10]) << 16;
+ fallthrough;
+ case 10:
+ k2 ^= ((u64)tail[9]) << 8;
+ fallthrough;
+ case 9:
+ k2 ^= ((u64)tail[8]) << 0;
+ k2 *= c2;
+ k2 = ROTL64(k2, 33);
+ k2 *= c1;
+ h2 ^= k2;
+ fallthrough;
+
+ case 8:
+ k1 ^= ((u64)tail[7]) << 56;
+ fallthrough;
+ case 7:
+ k1 ^= ((u64)tail[6]) << 48;
+ fallthrough;
+ case 6:
+ k1 ^= ((u64)tail[5]) << 40;
+ fallthrough;
+ case 5:
+ k1 ^= ((u64)tail[4]) << 32;
+ fallthrough;
+ case 4:
+ k1 ^= ((u64)tail[3]) << 24;
+ fallthrough;
+ case 3:
+ k1 ^= ((u64)tail[2]) << 16;
+ fallthrough;
+ case 2:
+ k1 ^= ((u64)tail[1]) << 8;
+ fallthrough;
+ case 1:
+ k1 ^= ((u64)tail[0]) << 0;
+ k1 *= c1;
+ k1 = ROTL64(k1, 31);
+ k1 *= c2;
+ h1 ^= k1;
+ break;
+ default:
+ break;
+ }
+ }
+ /* finalization */
+
+ h1 ^= len;
+ h2 ^= len;
+
+ h1 += h2;
+ h2 += h1;
+
+ h1 = fmix64(h1);
+ h2 = fmix64(h2);
+
+ h1 += h2;
+ h2 += h1;
+
+ put_unaligned_le64(h1, &hash_out[0]);
+ put_unaligned_le64(h2, &hash_out[1]);
+}