[linux-2.6-block.git] / drivers / xen / tmem.c

/*
 * Xen implementation for transcendent memory (tmem)
 *
 * Copyright (C) 2009-2011 Oracle Corp.  All rights reserved.
 * Author: Dan Magenheimer
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/cleancache.h>

/* temporary ifdef until include/linux/frontswap.h is upstream */
#ifdef CONFIG_FRONTSWAP
#include <linux/frontswap.h>
#endif

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
#include <asm/xen/hypervisor.h>

#define TMEM_CONTROL               0
#define TMEM_NEW_POOL              1
#define TMEM_DESTROY_POOL          2
#define TMEM_NEW_PAGE              3
#define TMEM_PUT_PAGE              4
#define TMEM_GET_PAGE              5
#define TMEM_FLUSH_PAGE            6
#define TMEM_FLUSH_OBJECT          7
#define TMEM_READ                  8
#define TMEM_WRITE                 9
#define TMEM_XCHG                 10

/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
#define TMEM_POOL_PERSIST          1
#define TMEM_POOL_SHARED           2
#define TMEM_POOL_PAGESIZE_SHIFT   4
#define TMEM_VERSION_SHIFT        24


struct tmem_pool_uuid {
	u64 uuid_lo;
	u64 uuid_hi;
};

struct tmem_oid {
	u64 oid[3];
};

#define TMEM_POOL_PRIVATE_UUID	{ 0, 0 }

/* flags for tmem_ops.new_pool */
#define TMEM_POOL_PERSIST          1
#define TMEM_POOL_SHARED           2

/* xen tmem foundation ops/hypercalls */

static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
{
	struct tmem_op op;
	int rc = 0;

	op.cmd = tmem_cmd;
	op.pool_id = tmem_pool;
	op.u.gen.oid[0] = oid.oid[0];
	op.u.gen.oid[1] = oid.oid[1];
	op.u.gen.oid[2] = oid.oid[2];
	op.u.gen.index = index;
	op.u.gen.tmem_offset = tmem_offset;
	op.u.gen.pfn_offset = pfn_offset;
	op.u.gen.len = len;
	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	rc = HYPERVISOR_tmem_op(&op);
	return rc;
}

static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
				u32 flags, unsigned long pagesize)
{
	struct tmem_op op;
	int rc = 0, pageshift;

	for (pageshift = 0; pagesize != 1; pageshift++)
		pagesize >>= 1;
	flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
	flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
	op.cmd = TMEM_NEW_POOL;
	op.u.new.uuid[0] = uuid.uuid_lo;
	op.u.new.uuid[1] = uuid.uuid_hi;
	op.u.new.flags = flags;
	rc = HYPERVISOR_tmem_op(&op);
	return rc;
}

/* xen generic tmem ops */

static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
			     u32 index, unsigned long pfn)
{
	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;

	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
		gmfn, 0, 0, 0);
}

static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
			     u32 index, unsigned long pfn)
{
	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;

	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
		gmfn, 0, 0, 0);
}

static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
{
	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
		0, 0, 0, 0);
}

static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
{
	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
}

bool __read_mostly tmem_enabled = false;

static int __init enable_tmem(char *s)
{
	tmem_enabled = true;
	return 1;
}
__setup("tmem", enable_tmem);

#ifdef CONFIG_CLEANCACHE
static int xen_tmem_destroy_pool(u32 pool_id)
{
	struct tmem_oid oid = { { 0 } };

	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
}

/* cleancache ops */

static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
				     pgoff_t index, struct page *page)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;
	unsigned long pfn = page_to_pfn(page);

	if (pool < 0)
		return;
	if (ind != index)
		return;
	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
}

static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
				    pgoff_t index, struct page *page)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;
	unsigned long pfn = page_to_pfn(page);
	int ret;

	/* translate return values to linux semantics */
	if (pool < 0)
		return -1;
	if (ind != index)
		return -1;
	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	if (ret == 1)
		return 0;
	else
		return -1;
}

static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
				       pgoff_t index)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;

	if (pool < 0)
		return;
	if (ind != index)
		return;
	(void)xen_tmem_flush_page((u32)pool, oid, ind);
}

static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
{
	struct tmem_oid oid = *(struct tmem_oid *)&key;

	if (pool < 0)
		return;
	(void)xen_tmem_flush_object((u32)pool, oid);
}

static void tmem_cleancache_flush_fs(int pool)
{
	if (pool < 0)
		return;
	(void)xen_tmem_destroy_pool((u32)pool);
}

static int tmem_cleancache_init_fs(size_t pagesize)
{
	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;

	return xen_tmem_new_pool(uuid_private, 0, pagesize);
}

static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
{
	struct tmem_pool_uuid shared_uuid;

	shared_uuid.uuid_lo = *(u64 *)uuid;
	shared_uuid.uuid_hi = *(u64 *)(&uuid[8]);
	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
}

static bool __initdata use_cleancache = true;

static int __init no_cleancache(char *s)
{
	use_cleancache = false;
	return 1;
}
__setup("nocleancache", no_cleancache);

static struct cleancache_ops __initdata tmem_cleancache_ops = {
	.put_page = tmem_cleancache_put_page,
	.get_page = tmem_cleancache_get_page,
	.invalidate_page = tmem_cleancache_flush_page,
	.invalidate_inode = tmem_cleancache_flush_inode,
	.invalidate_fs = tmem_cleancache_flush_fs,
	.init_shared_fs = tmem_cleancache_init_shared_fs,
	.init_fs = tmem_cleancache_init_fs
};
#endif

#ifdef CONFIG_FRONTSWAP
/* frontswap tmem operations */

/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
static int tmem_frontswap_poolid;

/*
 * Swizzling increases objects per swaptype, increasing tmem concurrency
 * for heavy swaploads.  Later, larger nr_cpus -> larger SWIZ_BITS
 */
#define SWIZ_BITS		4
#define SWIZ_MASK		((1 << SWIZ_BITS) - 1)
#define _oswiz(_type, _ind)	((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
#define iswiz(_ind)		(_ind >> SWIZ_BITS)

static inline struct tmem_oid oswiz(unsigned type, u32 ind)
{
	struct tmem_oid oid = { .oid = { 0 } };
	oid.oid[0] = _oswiz(type, ind);
	return oid;
}

/* returns 0 if the page was successfully put into frontswap, -1 if not */
static int tmem_frontswap_store(unsigned type, pgoff_t offset,
				   struct page *page)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	unsigned long pfn = page_to_pfn(page);
	int pool = tmem_frontswap_poolid;
	int ret;

	if (pool < 0)
		return -1;
	if (ind64 != ind)
		return -1;
	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	/* translate Xen tmem return values to linux semantics */
	if (ret == 1)
		return 0;
	else
		return -1;
}

/*
 * returns 0 if the page was successfully gotten from frontswap, -1 if
 * was not present (should never happen!)
 */
static int tmem_frontswap_load(unsigned type, pgoff_t offset,
				   struct page *page)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	unsigned long pfn = page_to_pfn(page);
	int pool = tmem_frontswap_poolid;
	int ret;

	if (pool < 0)
		return -1;
	if (ind64 != ind)
		return -1;
	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	/* translate Xen tmem return values to linux semantics */
	if (ret == 1)
		return 0;
	else
		return -1;
}

/* flush a single page from frontswap */
static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	int pool = tmem_frontswap_poolid;

	if (pool < 0)
		return;
	if (ind64 != ind)
		return;
	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
}

/* flush all pages from the passed swaptype */
static void tmem_frontswap_flush_area(unsigned type)
{
	int pool = tmem_frontswap_poolid;
	int ind;

	if (pool < 0)
		return;
	for (ind = SWIZ_MASK; ind >= 0; ind--)
		(void)xen_tmem_flush_object(pool, oswiz(type, ind));
}

static void tmem_frontswap_init(unsigned ignored)
{
	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;

	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	if (tmem_frontswap_poolid < 0)
		tmem_frontswap_poolid =
		    xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
}

static bool __initdata use_frontswap = true;

static int __init no_frontswap(char *s)
{
	use_frontswap = false;
	return 1;
}
__setup("nofrontswap", no_frontswap);

static struct frontswap_ops __initdata tmem_frontswap_ops = {
	.store = tmem_frontswap_store,
	.load = tmem_frontswap_load,
	.invalidate_page = tmem_frontswap_flush_page,
	.invalidate_area = tmem_frontswap_flush_area,
	.init = tmem_frontswap_init
};
#endif

static int __init xen_tmem_init(void)
{
	if (!xen_domain())
		return 0;
#ifdef CONFIG_FRONTSWAP
	if (tmem_enabled && use_frontswap) {
		char *s = "";
		struct frontswap_ops old_ops =
			frontswap_register_ops(&tmem_frontswap_ops);

		tmem_frontswap_poolid = -1;
		if (old_ops.init != NULL)
			s = " (WARNING: frontswap_ops overridden)";
		printk(KERN_INFO "frontswap enabled, RAM provided by "
				 "Xen Transcendent Memory\n");
	}
#endif
#ifdef CONFIG_CLEANCACHE
	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
	if (tmem_enabled && use_cleancache) {
		char *s = "";
		struct cleancache_ops old_ops =
			cleancache_register_ops(&tmem_cleancache_ops);
		if (old_ops.init_fs != NULL)
			s = " (WARNING: cleancache_ops overridden)";
		printk(KERN_INFO "cleancache enabled, RAM provided by "
				 "Xen Transcendent Memory%s\n", s);
	}
#endif
	return 0;
}

module_init(xen_tmem_init)
Commit	Line	Data
5bc20fc5 DM	1	/*
	2	* Xen implementation for transcendent memory (tmem)
	3	*
afec6e04	4	* Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
5bc20fc5 DM	5	* Author: Dan Magenheimer
	6	*/
	7
	8	#include <linux/kernel.h>
	9	#include <linux/types.h>
	10	#include <linux/init.h>
	11	#include <linux/pagemap.h>
	12	#include <linux/cleancache.h>
	13
afec6e04 DM	14	/* temporary ifdef until include/linux/frontswap.h is upstream */
	15	#ifdef CONFIG_FRONTSWAP
	16	#include <linux/frontswap.h>
	17	#endif
	18
5bc20fc5 DM	19	#include <xen/xen.h>
	20	#include <xen/interface/xen.h>
	21	#include <asm/xen/hypercall.h>
	22	#include <asm/xen/page.h>
	23	#include <asm/xen/hypervisor.h>
	24
	25	#define TMEM_CONTROL 0
	26	#define TMEM_NEW_POOL 1
	27	#define TMEM_DESTROY_POOL 2
	28	#define TMEM_NEW_PAGE 3
	29	#define TMEM_PUT_PAGE 4
	30	#define TMEM_GET_PAGE 5
	31	#define TMEM_FLUSH_PAGE 6
	32	#define TMEM_FLUSH_OBJECT 7
	33	#define TMEM_READ 8
	34	#define TMEM_WRITE 9
	35	#define TMEM_XCHG 10
	36
	37	/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
	38	#define TMEM_POOL_PERSIST 1
	39	#define TMEM_POOL_SHARED 2
	40	#define TMEM_POOL_PAGESIZE_SHIFT 4
	41	#define TMEM_VERSION_SHIFT 24
	42
	43
	44	struct tmem_pool_uuid {
	45	u64 uuid_lo;
	46	u64 uuid_hi;
	47	};
	48
	49	struct tmem_oid {
	50	u64 oid[3];
	51	};
	52
	53	#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
	54
	55	/* flags for tmem_ops.new_pool */
	56	#define TMEM_POOL_PERSIST 1
	57	#define TMEM_POOL_SHARED 2
	58
	59	/* xen tmem foundation ops/hypercalls */
	60
	61	static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	62	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
	63	{
	64	struct tmem_op op;
	65	int rc = 0;
	66
	67	op.cmd = tmem_cmd;
	68	op.pool_id = tmem_pool;
	69	op.u.gen.oid[0] = oid.oid[0];
	70	op.u.gen.oid[1] = oid.oid[1];
	71	op.u.gen.oid[2] = oid.oid[2];
	72	op.u.gen.index = index;
	73	op.u.gen.tmem_offset = tmem_offset;
	74	op.u.gen.pfn_offset = pfn_offset;
	75	op.u.gen.len = len;
	76	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	77	rc = HYPERVISOR_tmem_op(&op);
	78	return rc;
	79	}
	80
	81	static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
	82	u32 flags, unsigned long pagesize)
83	{
84	struct tmem_op op;
85	int rc = 0, pageshift;
86
87	for (pageshift = 0; pagesize != 1; pageshift++)
88	pagesize >>= 1;
89	flags \|= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
90	flags \|= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
91	op.cmd = TMEM_NEW_POOL;
92	op.u.new.uuid[0] = uuid.uuid_lo;
93	op.u.new.uuid[1] = uuid.uuid_hi;
94	op.u.new.flags = flags;
95	rc = HYPERVISOR_tmem_op(&op);
96	return rc;
97	}
98
99	/* xen generic tmem ops */
100
101	static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
102	u32 index, unsigned long pfn)
103	{
104	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
105
106	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
107	gmfn, 0, 0, 0);
108	}
109
110	static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
111	u32 index, unsigned long pfn)
112	{
113	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
114
115	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
116	gmfn, 0, 0, 0);
117	}
118
119	static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
120	{
121	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
122	0, 0, 0, 0);
123	}
124
125	static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
126	{
127	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
128	}
129
8e6f7c23	130	bool __read_mostly tmem_enabled = false;
5bc20fc5 DM	131
	132	static int __init enable_tmem(char *s)
	133	{
8e6f7c23	134	tmem_enabled = true;
5bc20fc5 DM	135	return 1;
5bc20fc5 DM	136	}
5bc20fc5 DM	137	__setup("tmem", enable_tmem);
5bc20fc5 DM	138
afec6e04 DM	139	#ifdef CONFIG_CLEANCACHE
	140	static int xen_tmem_destroy_pool(u32 pool_id)
	141	{
	142	struct tmem_oid oid = { { 0 } };
	143
	144	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
	145	}
	146
5bc20fc5 DM	147	/* cleancache ops */
	148
	149	static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
	150	pgoff_t index, struct page *page)
	151	{
	152	u32 ind = (u32) index;
	153	struct tmem_oid oid = (struct tmem_oid )&key;
	154	unsigned long pfn = page_to_pfn(page);
	155
	156	if (pool < 0)
	157	return;
	158	if (ind != index)
	159	return;
	160	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	161	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
	162	}
	163
	164	static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
	165	pgoff_t index, struct page *page)
	166	{
	167	u32 ind = (u32) index;
	168	struct tmem_oid oid = (struct tmem_oid )&key;
	169	unsigned long pfn = page_to_pfn(page);
	170	int ret;
	171
	172	/* translate return values to linux semantics */
	173	if (pool < 0)
	174	return -1;
	175	if (ind != index)
	176	return -1;
	177	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	178	if (ret == 1)
	179	return 0;
	180	else
	181	return -1;
	182	}
	183
	184	static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
	185	pgoff_t index)
	186	{
	187	u32 ind = (u32) index;
	188	struct tmem_oid oid = (struct tmem_oid )&key;
	189
	190	if (pool < 0)
	191	return;
	192	if (ind != index)
	193	return;
	194	(void)xen_tmem_flush_page((u32)pool, oid, ind);
	195	}
	196
	197	static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
	198	{
	199	struct tmem_oid oid = (struct tmem_oid )&key;
	200
	201	if (pool < 0)
	202	return;
	203	(void)xen_tmem_flush_object((u32)pool, oid);
	204	}
	205
	206	static void tmem_cleancache_flush_fs(int pool)
	207	{
	208	if (pool < 0)
	209	return;
	210	(void)xen_tmem_destroy_pool((u32)pool);
211	}
212
213	static int tmem_cleancache_init_fs(size_t pagesize)
214	{
215	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
216
217	return xen_tmem_new_pool(uuid_private, 0, pagesize);
218	}
219
220	static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
221	{
222	struct tmem_pool_uuid shared_uuid;
223
224	shared_uuid.uuid_lo = (u64 )uuid;
225	shared_uuid.uuid_hi = (u64 )(&uuid[8]);
226	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
227	}
228
8e6f7c23	229	static bool __initdata use_cleancache = true;
5bc20fc5 DM	230
	231	static int __init no_cleancache(char *s)
	232	{
8e6f7c23	233	use_cleancache = false;
5bc20fc5 DM	234	return 1;
5bc20fc5 DM	235	}
5bc20fc5 DM	236	__setup("nocleancache", no_cleancache);
5bc20fc5 DM	237
8e6f7c23	238	static struct cleancache_ops __initdata tmem_cleancache_ops = {
5bc20fc5 DM	239	.put_page = tmem_cleancache_put_page,
5bc20fc5 DM	240	.get_page = tmem_cleancache_get_page,
91c6cc9b DM	241	.invalidate_page = tmem_cleancache_flush_page,
	242	.invalidate_inode = tmem_cleancache_flush_inode,
	243	.invalidate_fs = tmem_cleancache_flush_fs,
5bc20fc5 DM	244	.init_shared_fs = tmem_cleancache_init_shared_fs,
	245	.init_fs = tmem_cleancache_init_fs
	246	};
afec6e04	247	#endif
5bc20fc5	248
afec6e04 DM	249	#ifdef CONFIG_FRONTSWAP
	250	/* frontswap tmem operations */
	251
	252	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	253	static int tmem_frontswap_poolid;
	254
	255	/*
	256	* Swizzling increases objects per swaptype, increasing tmem concurrency
	257	* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
	258	*/
	259	#define SWIZ_BITS 4
	260	#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
	261	#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) \| (_ind & SWIZ_MASK))
	262	#define iswiz(_ind) (_ind >> SWIZ_BITS)
	263
	264	static inline struct tmem_oid oswiz(unsigned type, u32 ind)
5bc20fc5	265	{
afec6e04 DM	266	struct tmem_oid oid = { .oid = { 0 } };
	267	oid.oid[0] = _oswiz(type, ind);
	268	return oid;
	269	}
5bc20fc5	270
afec6e04	271	/* returns 0 if the page was successfully put into frontswap, -1 if not */
165c8aed	272	static int tmem_frontswap_store(unsigned type, pgoff_t offset,
afec6e04 DM	273	struct page *page)
	274	{
	275	u64 ind64 = (u64)offset;
	276	u32 ind = (u32)offset;
	277	unsigned long pfn = page_to_pfn(page);
	278	int pool = tmem_frontswap_poolid;
	279	int ret;
	280
	281	if (pool < 0)
	282	return -1;
	283	if (ind64 != ind)
	284	return -1;
	285	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	286	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	287	/* translate Xen tmem return values to linux semantics */
	288	if (ret == 1)
	289	return 0;
	290	else
	291	return -1;
	292	}
	293
	294	/*
	295	* returns 0 if the page was successfully gotten from frontswap, -1 if
	296	* was not present (should never happen!)
	297	*/
165c8aed	298	static int tmem_frontswap_load(unsigned type, pgoff_t offset,
afec6e04 DM	299	struct page *page)
	300	{
	301	u64 ind64 = (u64)offset;
	302	u32 ind = (u32)offset;
	303	unsigned long pfn = page_to_pfn(page);
	304	int pool = tmem_frontswap_poolid;
	305	int ret;
	306
	307	if (pool < 0)
	308	return -1;
	309	if (ind64 != ind)
	310	return -1;
	311	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	312	/* translate Xen tmem return values to linux semantics */
	313	if (ret == 1)
	314	return 0;
	315	else
	316	return -1;
	317	}
	318
	319	/* flush a single page from frontswap */
	320	static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
	321	{
	322	u64 ind64 = (u64)offset;
	323	u32 ind = (u32)offset;
	324	int pool = tmem_frontswap_poolid;
	325
	326	if (pool < 0)
	327	return;
	328	if (ind64 != ind)
	329	return;
	330	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
	331	}
	332
	333	/* flush all pages from the passed swaptype */
	334	static void tmem_frontswap_flush_area(unsigned type)
	335	{
	336	int pool = tmem_frontswap_poolid;
	337	int ind;
	338
	339	if (pool < 0)
	340	return;
	341	for (ind = SWIZ_MASK; ind >= 0; ind--)
	342	(void)xen_tmem_flush_object(pool, oswiz(type, ind));
	343	}
	344
	345	static void tmem_frontswap_init(unsigned ignored)
	346	{
	347	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
	348
	349	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	350	if (tmem_frontswap_poolid < 0)
	351	tmem_frontswap_poolid =
	352	xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
	353	}
	354
8e6f7c23	355	static bool __initdata use_frontswap = true;
afec6e04 DM	356
	357	static int __init no_frontswap(char *s)
	358	{
8e6f7c23	359	use_frontswap = false;
afec6e04 DM	360	return 1;
afec6e04 DM	361	}
afec6e04 DM	362	__setup("nofrontswap", no_frontswap);
afec6e04 DM	363
8e6f7c23	364	static struct frontswap_ops __initdata tmem_frontswap_ops = {
165c8aed KRW	365	.store = tmem_frontswap_store,
165c8aed KRW	366	.load = tmem_frontswap_load,
91c6cc9b DM	367	.invalidate_page = tmem_frontswap_flush_page,
91c6cc9b DM	368	.invalidate_area = tmem_frontswap_flush_area,
afec6e04 DM	369	.init = tmem_frontswap_init
	370	};
	371	#endif
	372
	373	static int __init xen_tmem_init(void)
	374	{
5bc20fc5 DM	375	if (!xen_domain())
5bc20fc5 DM	376	return 0;
afec6e04 DM	377	#ifdef CONFIG_FRONTSWAP
	378	if (tmem_enabled && use_frontswap) {
	379	char *s = "";
	380	struct frontswap_ops old_ops =
	381	frontswap_register_ops(&tmem_frontswap_ops);
	382
	383	tmem_frontswap_poolid = -1;
	384	if (old_ops.init != NULL)
	385	s = " (WARNING: frontswap_ops overridden)";
	386	printk(KERN_INFO "frontswap enabled, RAM provided by "
	387	"Xen Transcendent Memory\n");
	388	}
	389	#endif
5bc20fc5 DM	390	#ifdef CONFIG_CLEANCACHE
	391	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
	392	if (tmem_enabled && use_cleancache) {
	393	char *s = "";
afec6e04 DM	394	struct cleancache_ops old_ops =
afec6e04 DM	395	cleancache_register_ops(&tmem_cleancache_ops);
5bc20fc5 DM	396	if (old_ops.init_fs != NULL)
	397	s = " (WARNING: cleancache_ops overridden)";
	398	printk(KERN_INFO "cleancache enabled, RAM provided by "
	399	"Xen Transcendent Memory%s\n", s);
	400	}
	401	#endif
	402	return 0;
	403	}
	404
	405	module_init(xen_tmem_init)