Initial import

3 files changed, 246 insertions, 0 deletions

diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
new file mode 100644
index 000000000..48a1a7d10
--- /dev/null
+++ b/include/linux/crush/crush.h
@@ -0,0 +1,209 @@
+#ifndef CEPH_CRUSH_CRUSH_H
+#define CEPH_CRUSH_CRUSH_H
+
+#include <linux/types.h>
+
+/*
+ * CRUSH is a pseudo-random data distribution algorithm that
+ * efficiently distributes input values (typically, data objects)
+ * across a heterogeneous, structured storage cluster.
+ *
+ * The algorithm was originally described in detail in this paper
+ * (although the algorithm has evolved somewhat since then):
+ *
+ *     http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
+ *
+ * LGPL2
+ */
+
+
+#define CRUSH_MAGIC 0x00010000ul   /* for detecting algorithm revisions */
+
+#define CRUSH_MAX_DEPTH 10  /* max crush hierarchy depth */
+
+
+#define CRUSH_ITEM_UNDEF  0x7ffffffe  /* undefined result (internal use only) */
+#define CRUSH_ITEM_NONE   0x7fffffff  /* no result */
+
+/*
+ * CRUSH uses user-defined "rules" to describe how inputs should be
+ * mapped to devices.  A rule consists of sequence of steps to perform
+ * to generate the set of output devices.
+ */
+struct crush_rule_step {
+	__u32 op;
+	__s32 arg1;
+	__s32 arg2;
+};
+
+/* step op codes */
+enum {
+	CRUSH_RULE_NOOP = 0,
+	CRUSH_RULE_TAKE = 1,          /* arg1 = value to start with */
+	CRUSH_RULE_CHOOSE_FIRSTN = 2, /* arg1 = num items to pick */
+				      /* arg2 = type */
+	CRUSH_RULE_CHOOSE_INDEP = 3,  /* same */
+	CRUSH_RULE_EMIT = 4,          /* no args */
+	CRUSH_RULE_CHOOSELEAF_FIRSTN = 6,
+	CRUSH_RULE_CHOOSELEAF_INDEP = 7,
+
+	CRUSH_RULE_SET_CHOOSE_TRIES = 8, /* override choose_total_tries */
+	CRUSH_RULE_SET_CHOOSELEAF_TRIES = 9, /* override chooseleaf_descend_once */
+	CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES = 10,
+	CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES = 11,
+	CRUSH_RULE_SET_CHOOSELEAF_VARY_R = 12
+};
+
+/*
+ * for specifying choose num (arg1) relative to the max parameter
+ * passed to do_rule
+ */
+#define CRUSH_CHOOSE_N            0
+#define CRUSH_CHOOSE_N_MINUS(x)   (-(x))
+
+/*
+ * The rule mask is used to describe what the rule is intended for.
+ * Given a ruleset and size of output set, we search through the
+ * rule list for a matching rule_mask.
+ */
+struct crush_rule_mask {
+	__u8 ruleset;
+	__u8 type;
+	__u8 min_size;
+	__u8 max_size;
+};
+
+struct crush_rule {
+	__u32 len;
+	struct crush_rule_mask mask;
+	struct crush_rule_step steps[0];
+};
+
+#define crush_rule_size(len) (sizeof(struct crush_rule) + \
+			      (len)*sizeof(struct crush_rule_step))
+
+
+
+/*
+ * A bucket is a named container of other items (either devices or
+ * other buckets).  Items within a bucket are chosen using one of a
+ * few different algorithms.  The table summarizes how the speed of
+ * each option measures up against mapping stability when items are
+ * added or removed.
+ *
+ *  Bucket Alg     Speed       Additions    Removals
+ *  ------------------------------------------------
+ *  uniform         O(1)       poor         poor
+ *  list            O(n)       optimal      poor
+ *  tree            O(log n)   good         good
+ *  straw           O(n)       better       better
+ *  straw2          O(n)       optimal      optimal
+ */
+enum {
+	CRUSH_BUCKET_UNIFORM = 1,
+	CRUSH_BUCKET_LIST = 2,
+	CRUSH_BUCKET_TREE = 3,
+	CRUSH_BUCKET_STRAW = 4,
+	CRUSH_BUCKET_STRAW2 = 5,
+};
+extern const char *crush_bucket_alg_name(int alg);
+
+struct crush_bucket {
+	__s32 id;        /* this'll be negative */
+	__u16 type;      /* non-zero; type=0 is reserved for devices */
+	__u8 alg;        /* one of CRUSH_BUCKET_* */
+	__u8 hash;       /* which hash function to use, CRUSH_HASH_* */
+	__u32 weight;    /* 16-bit fixed point */
+	__u32 size;      /* num items */
+	__s32 *items;
+
+	/*
+	 * cached random permutation: used for uniform bucket and for
+	 * the linear search fallback for the other bucket types.
+	 */
+	__u32 perm_x;  /* @x for which *perm is defined */
+	__u32 perm_n;  /* num elements of *perm that are permuted/defined */
+	__u32 *perm;
+};
+
+struct crush_bucket_uniform {
+	struct crush_bucket h;
+	__u32 item_weight;  /* 16-bit fixed point; all items equally weighted */
+};
+
+struct crush_bucket_list {
+	struct crush_bucket h;
+	__u32 *item_weights;  /* 16-bit fixed point */
+	__u32 *sum_weights;   /* 16-bit fixed point.  element i is sum
+				 of weights 0..i, inclusive */
+};
+
+struct crush_bucket_tree {
+	struct crush_bucket h;  /* note: h.size is _tree_ size, not number of
+				   actual items */
+	__u8 num_nodes;
+	__u32 *node_weights;
+};
+
+struct crush_bucket_straw {
+	struct crush_bucket h;
+	__u32 *item_weights;   /* 16-bit fixed point */
+	__u32 *straws;         /* 16-bit fixed point */
+};
+
+struct crush_bucket_straw2 {
+	struct crush_bucket h;
+	__u32 *item_weights;   /* 16-bit fixed point */
+};
+
+
+
+/*
+ * CRUSH map includes all buckets, rules, etc.
+ */
+struct crush_map {
+	struct crush_bucket **buckets;
+	struct crush_rule **rules;
+
+	__s32 max_buckets;
+	__u32 max_rules;
+	__s32 max_devices;
+
+	/* choose local retries before re-descent */
+	__u32 choose_local_tries;
+	/* choose local attempts using a fallback permutation before
+	 * re-descent */
+	__u32 choose_local_fallback_tries;
+	/* choose attempts before giving up */ 
+	__u32 choose_total_tries;
+	/* attempt chooseleaf inner descent once for firstn mode; on
+	 * reject retry outer descent.  Note that this does *not*
+	 * apply to a collision: in that case we will retry as we used
+	 * to. */
+	__u32 chooseleaf_descend_once;
+
+	/* if non-zero, feed r into chooseleaf, bit-shifted right by (r-1)
+	 * bits.  a value of 1 is best for new clusters.  for legacy clusters
+	 * that want to limit reshuffling, a value of 3 or 4 will make the
+	 * mappings line up a bit better with previous mappings. */
+	__u8 chooseleaf_vary_r;
+};
+
+
+/* crush.c */
+extern int crush_get_bucket_item_weight(const struct crush_bucket *b, int pos);
+extern void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b);
+extern void crush_destroy_bucket_list(struct crush_bucket_list *b);
+extern void crush_destroy_bucket_tree(struct crush_bucket_tree *b);
+extern void crush_destroy_bucket_straw(struct crush_bucket_straw *b);
+extern void crush_destroy_bucket_straw2(struct crush_bucket_straw2 *b);
+extern void crush_destroy_bucket(struct crush_bucket *b);
+extern void crush_destroy_rule(struct crush_rule *r);
+extern void crush_destroy(struct crush_map *map);
+
+static inline int crush_calc_tree_node(int i)
+{
+	return ((i+1) << 1)-1;
+}
+
+#endif
diff --git a/include/linux/crush/hash.h b/include/linux/crush/hash.h
new file mode 100644
index 000000000..91e884230
--- /dev/null
+++ b/include/linux/crush/hash.h
@@ -0,0 +1,17 @@
+#ifndef CEPH_CRUSH_HASH_H
+#define CEPH_CRUSH_HASH_H
+
+#define CRUSH_HASH_RJENKINS1   0
+
+#define CRUSH_HASH_DEFAULT CRUSH_HASH_RJENKINS1
+
+extern const char *crush_hash_name(int type);
+
+extern __u32 crush_hash32(int type, __u32 a);
+extern __u32 crush_hash32_2(int type, __u32 a, __u32 b);
+extern __u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c);
+extern __u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d);
+extern __u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d,
+			    __u32 e);
+
+#endif
diff --git a/include/linux/crush/mapper.h b/include/linux/crush/mapper.h
new file mode 100644
index 000000000..eab367446
--- /dev/null
+++ b/include/linux/crush/mapper.h
@@ -0,0 +1,20 @@
+#ifndef CEPH_CRUSH_MAPPER_H
+#define CEPH_CRUSH_MAPPER_H
+
+/*
+ * CRUSH functions for find rules and then mapping an input to an
+ * output set.
+ *
+ * LGPL2
+ */
+
+#include <linux/crush/crush.h>
+
+extern int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size);
+extern int crush_do_rule(const struct crush_map *map,
+			 int ruleno,
+			 int x, int *result, int result_max,
+			 const __u32 *weights, int weight_max,
+			 int *scratch);
+
+#endif