1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/murmurhash3.c b/drivers/md/dm-vdo/murmurhash3.c
new file mode 100644
index 000000000000..00c9b9c05001
--- /dev/null
+++ b/drivers/md/dm-vdo/murmurhash3.c
@@ -0,0 +1,175 @@
+// 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"
+
+static inline u64 rotl64(u64 x, s8 r)
+{
+	return (x << r) | (x >> (64 - r));
+}
+
+#define ROTL64(x, y) rotl64(x, y)
+static __always_inline u64 getblock64(const u64 *p, int i)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return p[i];
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	return __builtin_bswap64(p[i]);
+#else
+#error "can't figure out byte order"
+#endif
+}
+
+static __always_inline void putblock64(u64 *p, int i, u64 value)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	p[i] = value;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	p[i] = __builtin_bswap64(value);
+#else
+#error "can't figure out byte order"
+#endif
+}
+
+/* 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;
+
+	/* body */
+
+	const u64 *blocks = (const u64 *)(data);
+
+	int i;
+
+	for (i = 0; i < nblocks; i++) {
+		u64 k1 = getblock64(blocks, i * 2 + 0);
+		u64 k2 = getblock64(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;
+
+	putblock64((u64 *)out, 0, h1);
+	putblock64((u64 *)out, 1, h2);
+}