staging: zcache: rename ramster to zcache

[V2: no code changes, patchset now generated via git format-patch -M]

In staging, rename ramster to zcache

The original zcache in staging was a "demo" version, and this new zcache
is a significant rewrite.  While certain disagreements were being resolved,
both "old zcache" and "new zcache" needed to reside in the staging tree
simultaneously.  In order to minimize code change and churn, the newer
version of zcache was temporarily merged into the "ramster" staging driver
which, prior to that, had at one time heavily leveraged the older version
of zcache.  So, recently, "new zcache" resided in the ramster directory.

Got that? No? Sorry, temporary political compromises are rarely pretty.

The older version of zcache is no longer being maintained and has now
been removed from the staging tree.  So now the newer version of zcache
can rightfully reclaim sole possession of the name "zcache".

FYI, this [PATCH 2/5] is simply a "git mv" generated by "git format-patch -M".

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 259 insertions, 0 deletions

diff --git a/drivers/staging/zcache/tmem.h b/drivers/staging/zcache/tmem.h
new file mode 100644
index 000000000000..adbe5a8f28aa
--- /dev/null
+++ b/drivers/staging/zcache/tmem.h
@@ -0,0 +1,259 @@
+/*
+ * tmem.h
+ *
+ * Transcendent memory
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _TMEM_H_
+#define _TMEM_H_
+
+#include <linux/types.h>
+#include <linux/highmem.h>
+#include <linux/hash.h>
+#include <linux/atomic.h>
+
+/*
+ * These are defined by the Xen<->Linux ABI so should remain consistent
+ */
+#define TMEM_POOL_PERSIST		1
+#define TMEM_POOL_SHARED		2
+#define TMEM_POOL_PRECOMPRESSED		4
+#define TMEM_POOL_PAGESIZE_SHIFT	4
+#define TMEM_POOL_PAGESIZE_MASK		0xf
+#define TMEM_POOL_RESERVED_BITS		0x00ffff00
+
+/*
+ * sentinels have proven very useful for debugging but can be removed
+ * or disabled before final merge.
+ */
+#undef SENTINELS
+#ifdef SENTINELS
+#define DECL_SENTINEL uint32_t sentinel;
+#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
+#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
+#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
+#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
+#else
+#define DECL_SENTINEL
+#define SET_SENTINEL(_x, _y) do { } while (0)
+#define INVERT_SENTINEL(_x, _y) do { } while (0)
+#define ASSERT_SENTINEL(_x, _y) do { } while (0)
+#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
+#endif
+
+#define ASSERT_SPINLOCK(_l)	lockdep_assert_held(_l)
+
+/*
+ * A pool is the highest-level data structure managed by tmem and
+ * usually corresponds to a large independent set of pages such as
+ * a filesystem.  Each pool has an id, and certain attributes and counters.
+ * It also contains a set of hash buckets, each of which contains an rbtree
+ * of objects and a lock to manage concurrency within the pool.
+ */
+
+#define TMEM_HASH_BUCKET_BITS	8
+#define TMEM_HASH_BUCKETS	(1<<TMEM_HASH_BUCKET_BITS)
+
+struct tmem_hashbucket {
+	struct rb_root obj_rb_root;
+	spinlock_t lock;
+};
+
+struct tmem_pool {
+	void *client; /* "up" for some clients, avoids table lookup */
+	struct list_head pool_list;
+	uint32_t pool_id;
+	bool persistent;
+	bool shared;
+	atomic_t obj_count;
+	atomic_t refcount;
+	struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
+	DECL_SENTINEL
+};
+
+#define is_persistent(_p)  (_p->persistent)
+#define is_ephemeral(_p)   (!(_p->persistent))
+
+/*
+ * An object id ("oid") is large: 192-bits (to ensure, for example, files
+ * in a modern filesystem can be uniquely identified).
+ */
+
+struct tmem_oid {
+	uint64_t oid[3];
+};
+
+static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
+{
+	oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
+}
+
+static inline bool tmem_oid_valid(struct tmem_oid *oidp)
+{
+	return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL ||
+		oidp->oid[2] != -1UL;
+}
+
+static inline int tmem_oid_compare(struct tmem_oid *left,
+					struct tmem_oid *right)
+{
+	int ret;
+
+	if (left->oid[2] == right->oid[2]) {
+		if (left->oid[1] == right->oid[1]) {
+			if (left->oid[0] == right->oid[0])
+				ret = 0;
+			else if (left->oid[0] < right->oid[0])
+				ret = -1;
+			else
+				return 1;
+		} else if (left->oid[1] < right->oid[1])
+			ret = -1;
+		else
+			ret = 1;
+	} else if (left->oid[2] < right->oid[2])
+		ret = -1;
+	else
+		ret = 1;
+	return ret;
+}
+
+static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
+{
+	return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
+				TMEM_HASH_BUCKET_BITS);
+}
+
+#ifdef CONFIG_RAMSTER
+struct tmem_xhandle {
+	uint8_t client_id;
+	uint8_t xh_data_cksum;
+	uint16_t xh_data_size;
+	uint16_t pool_id;
+	struct tmem_oid oid;
+	uint32_t index;
+	void *extra;
+};
+
+static inline struct tmem_xhandle tmem_xhandle_fill(uint16_t client_id,
+					struct tmem_pool *pool,
+					struct tmem_oid *oidp,
+					uint32_t index)
+{
+	struct tmem_xhandle xh;
+	xh.client_id = client_id;
+	xh.xh_data_cksum = (uint8_t)-1;
+	xh.xh_data_size = (uint16_t)-1;
+	xh.pool_id = pool->pool_id;
+	xh.oid = *oidp;
+	xh.index = index;
+	return xh;
+}
+#endif
+
+
+/*
+ * A tmem_obj contains an identifier (oid), pointers to the parent
+ * pool and the rb_tree to which it belongs, counters, and an ordered
+ * set of pampds, structured in a radix-tree-like tree.  The intermediate
+ * nodes of the tree are called tmem_objnodes.
+ */
+
+struct tmem_objnode;
+
+struct tmem_obj {
+	struct tmem_oid oid;
+	struct tmem_pool *pool;
+	struct rb_node rb_tree_node;
+	struct tmem_objnode *objnode_tree_root;
+	unsigned int objnode_tree_height;
+	unsigned long objnode_count;
+	long pampd_count;
+#ifdef CONFIG_RAMSTER
+	/*
+	 * for current design of ramster, all pages belonging to
+	 * an object reside on the same remotenode and extra is
+	 * used to record the number of the remotenode so a
+	 * flush-object operation can specify it
+	 */
+	void *extra; /* for private use by pampd implementation */
+#endif
+	DECL_SENTINEL
+};
+
+#define OBJNODE_TREE_MAP_SHIFT 6
+#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
+#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
+#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
+#define OBJNODE_TREE_MAX_PATH \
+		(OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)
+
+struct tmem_objnode {
+	struct tmem_obj *obj;
+	DECL_SENTINEL
+	void *slots[OBJNODE_TREE_MAP_SIZE];
+	unsigned int slots_in_use;
+};
+
+struct tmem_handle {
+	struct tmem_oid oid; /* 24 bytes */
+	uint32_t index;
+	uint16_t pool_id;
+	uint16_t client_id;
+};
+
+
+/* pampd abstract datatype methods provided by the PAM implementation */
+struct tmem_pamops {
+	void (*create_finish)(void *, bool);
+	int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *,
+				struct tmem_oid *, uint32_t);
+	int (*get_data_and_free)(char *, size_t *, bool, void *,
+				struct tmem_pool *, struct tmem_oid *,
+				uint32_t);
+	void (*free)(void *, struct tmem_pool *,
+				struct tmem_oid *, uint32_t, bool);
+#ifdef CONFIG_RAMSTER
+	void (*new_obj)(struct tmem_obj *);
+	void (*free_obj)(struct tmem_pool *, struct tmem_obj *, bool);
+	void *(*repatriate_preload)(void *, struct tmem_pool *,
+					struct tmem_oid *, uint32_t, bool *);
+	int (*repatriate)(void *, void *, struct tmem_pool *,
+				struct tmem_oid *, uint32_t, bool, void *);
+	bool (*is_remote)(void *);
+	int (*replace_in_obj)(void *, struct tmem_obj *);
+#endif
+};
+extern void tmem_register_pamops(struct tmem_pamops *m);
+
+/* memory allocation methods provided by the host implementation */
+struct tmem_hostops {
+	struct tmem_obj *(*obj_alloc)(struct tmem_pool *);
+	void (*obj_free)(struct tmem_obj *, struct tmem_pool *);
+	struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *);
+	void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *);
+};
+extern void tmem_register_hostops(struct tmem_hostops *m);
+
+/* core tmem accessor functions */
+extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+			bool, void *);
+extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+			char *, size_t *, bool, int);
+extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
+			uint32_t index);
+extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
+extern int tmem_destroy_pool(struct tmem_pool *);
+extern void tmem_new_pool(struct tmem_pool *, uint32_t);
+#ifdef CONFIG_RAMSTER
+extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+			void *);
+extern void *tmem_localify_get_pampd(struct tmem_pool *, struct tmem_oid *,
+				   uint32_t index, struct tmem_obj **,
+				   void **);
+extern void tmem_localify_finish(struct tmem_obj *, uint32_t index,
+				 void *, void *, bool);
+#endif
+#endif /* _TMEM_H */