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authorDavid S. Miller <davem@davemloft.net>2010-04-06 23:53:30 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-06 23:53:30 -0700
commit4a35ecf8bf1c4b039503fa554100fe85c761de76 (patch)
tree9b75f5d5636004d9a9aa496924377379be09aa1f /fs/ceph/crush/hash.c
parentb4d562e3c3553ac58c7120555c4e4aefbb090a2a (diff)
parentfb9e2d887243499b8d28efcf80821c4f6a092395 (diff)
downloadlinux-4a35ecf8bf1c4b039503fa554100fe85c761de76.tar.bz2
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts: drivers/net/bonding/bond_main.c drivers/net/via-velocity.c drivers/net/wireless/iwlwifi/iwl-agn.c
Diffstat (limited to 'fs/ceph/crush/hash.c')
-rw-r--r--fs/ceph/crush/hash.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/fs/ceph/crush/hash.c b/fs/ceph/crush/hash.c
new file mode 100644
index 000000000000..5873aed694bf
--- /dev/null
+++ b/fs/ceph/crush/hash.c
@@ -0,0 +1,149 @@
+
+#include <linux/types.h>
+#include "hash.h"
+
+/*
+ * Robert Jenkins' function for mixing 32-bit values
+ * http://burtleburtle.net/bob/hash/evahash.html
+ * a, b = random bits, c = input and output
+ */
+#define crush_hashmix(a, b, c) do { \
+ a = a-b; a = a-c; a = a^(c>>13); \
+ b = b-c; b = b-a; b = b^(a<<8); \
+ c = c-a; c = c-b; c = c^(b>>13); \
+ a = a-b; a = a-c; a = a^(c>>12); \
+ b = b-c; b = b-a; b = b^(a<<16); \
+ c = c-a; c = c-b; c = c^(b>>5); \
+ a = a-b; a = a-c; a = a^(c>>3); \
+ b = b-c; b = b-a; b = b^(a<<10); \
+ c = c-a; c = c-b; c = c^(b>>15); \
+ } while (0)
+
+#define crush_hash_seed 1315423911
+
+static __u32 crush_hash32_rjenkins1(__u32 a)
+{
+ __u32 hash = crush_hash_seed ^ a;
+ __u32 b = a;
+ __u32 x = 231232;
+ __u32 y = 1232;
+ crush_hashmix(b, x, hash);
+ crush_hashmix(y, a, hash);
+ return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_2(__u32 a, __u32 b)
+{
+ __u32 hash = crush_hash_seed ^ a ^ b;
+ __u32 x = 231232;
+ __u32 y = 1232;
+ crush_hashmix(a, b, hash);
+ crush_hashmix(x, a, hash);
+ crush_hashmix(b, y, hash);
+ return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_3(__u32 a, __u32 b, __u32 c)
+{
+ __u32 hash = crush_hash_seed ^ a ^ b ^ c;
+ __u32 x = 231232;
+ __u32 y = 1232;
+ crush_hashmix(a, b, hash);
+ crush_hashmix(c, x, hash);
+ crush_hashmix(y, a, hash);
+ crush_hashmix(b, x, hash);
+ crush_hashmix(y, c, hash);
+ return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_4(__u32 a, __u32 b, __u32 c, __u32 d)
+{
+ __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;
+ __u32 x = 231232;
+ __u32 y = 1232;
+ crush_hashmix(a, b, hash);
+ crush_hashmix(c, d, hash);
+ crush_hashmix(a, x, hash);
+ crush_hashmix(y, b, hash);
+ crush_hashmix(c, x, hash);
+ crush_hashmix(y, d, hash);
+ return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_5(__u32 a, __u32 b, __u32 c, __u32 d,
+ __u32 e)
+{
+ __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;
+ __u32 x = 231232;
+ __u32 y = 1232;
+ crush_hashmix(a, b, hash);
+ crush_hashmix(c, d, hash);
+ crush_hashmix(e, x, hash);
+ crush_hashmix(y, a, hash);
+ crush_hashmix(b, x, hash);
+ crush_hashmix(y, c, hash);
+ crush_hashmix(d, x, hash);
+ crush_hashmix(y, e, hash);
+ return hash;
+}
+
+
+__u32 crush_hash32(int type, __u32 a)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return crush_hash32_rjenkins1(a);
+ default:
+ return 0;
+ }
+}
+
+__u32 crush_hash32_2(int type, __u32 a, __u32 b)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return crush_hash32_rjenkins1_2(a, b);
+ default:
+ return 0;
+ }
+}
+
+__u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return crush_hash32_rjenkins1_3(a, b, c);
+ default:
+ return 0;
+ }
+}
+
+__u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return crush_hash32_rjenkins1_4(a, b, c, d);
+ default:
+ return 0;
+ }
+}
+
+__u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d, __u32 e)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return crush_hash32_rjenkins1_5(a, b, c, d, e);
+ default:
+ return 0;
+ }
+}
+
+const char *crush_hash_name(int type)
+{
+ switch (type) {
+ case CRUSH_HASH_RJENKINS1:
+ return "rjenkins1";
+ default:
+ return "unknown";
+ }
+}