[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>
#include <xen/tmem.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 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)
			s = " (WARNING: frontswap_ops overridden)";
		printk(KERN_INFO "frontswap enabled, RAM provided by "
				 "Xen Transcendent Memory%s\n", s);
	}
#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>
b8b0f559	24	#include <xen/tmem.h>
5bc20fc5 DM	25
	26	#define TMEM_CONTROL 0
	27	#define TMEM_NEW_POOL 1
	28	#define TMEM_DESTROY_POOL 2
	29	#define TMEM_NEW_PAGE 3
	30	#define TMEM_PUT_PAGE 4
	31	#define TMEM_GET_PAGE 5
	32	#define TMEM_FLUSH_PAGE 6
	33	#define TMEM_FLUSH_OBJECT 7
	34	#define TMEM_READ 8
	35	#define TMEM_WRITE 9
	36	#define TMEM_XCHG 10
	37
	38	/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
	39	#define TMEM_POOL_PERSIST 1
	40	#define TMEM_POOL_SHARED 2
	41	#define TMEM_POOL_PAGESIZE_SHIFT 4
	42	#define TMEM_VERSION_SHIFT 24
	43
	44
	45	struct tmem_pool_uuid {
	46	u64 uuid_lo;
	47	u64 uuid_hi;
	48	};
	49
	50	struct tmem_oid {
	51	u64 oid[3];
	52	};
	53
	54	#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
	55
	56	/* flags for tmem_ops.new_pool */
	57	#define TMEM_POOL_PERSIST 1
	58	#define TMEM_POOL_SHARED 2
	59
	60	/* xen tmem foundation ops/hypercalls */
	61
	62	static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	63	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
	64	{
	65	struct tmem_op op;
	66	int rc = 0;
	67
	68	op.cmd = tmem_cmd;
	69	op.pool_id = tmem_pool;
	70	op.u.gen.oid[0] = oid.oid[0];
	71	op.u.gen.oid[1] = oid.oid[1];
	72	op.u.gen.oid[2] = oid.oid[2];
	73	op.u.gen.index = index;
	74	op.u.gen.tmem_offset = tmem_offset;
	75	op.u.gen.pfn_offset = pfn_offset;
	76	op.u.gen.len = len;
	77	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	78	rc = HYPERVISOR_tmem_op(&op);
	79	return rc;
	80	}
	81
	82	static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
	83	u32 flags, unsigned long pagesize)
	84	{
	85	struct tmem_op op;
	86	int rc = 0, pageshift;
	87
	88	for (pageshift = 0; pagesize != 1; pageshift++)
89	pagesize >>= 1;
90	flags \|= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
91	flags \|= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
92	op.cmd = TMEM_NEW_POOL;
93	op.u.new.uuid[0] = uuid.uuid_lo;
94	op.u.new.uuid[1] = uuid.uuid_hi;
95	op.u.new.flags = flags;
96	rc = HYPERVISOR_tmem_op(&op);
97	return rc;
98	}
99
100	/* xen generic tmem ops */
101
102	static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
103	u32 index, unsigned long pfn)
104	{
105	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
106
107	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
108	gmfn, 0, 0, 0);
109	}
110
111	static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
112	u32 index, unsigned long pfn)
113	{
114	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
115
116	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
117	gmfn, 0, 0, 0);
118	}
119
120	static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
121	{
122	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
123	0, 0, 0, 0);
124	}
125
126	static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
127	{
128	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
129	}
130
8e6f7c23	131	bool __read_mostly tmem_enabled = false;
5bc20fc5 DM	132
	133	static int __init enable_tmem(char *s)
	134	{
8e6f7c23	135	tmem_enabled = true;
5bc20fc5 DM	136	return 1;
5bc20fc5 DM	137	}
5bc20fc5 DM	138	__setup("tmem", enable_tmem);
5bc20fc5 DM	139
afec6e04 DM	140	#ifdef CONFIG_CLEANCACHE
	141	static int xen_tmem_destroy_pool(u32 pool_id)
	142	{
	143	struct tmem_oid oid = { { 0 } };
	144
	145	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
	146	}
	147
5bc20fc5 DM	148	/* cleancache ops */
	149
	150	static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
	151	pgoff_t index, struct page *page)
	152	{
	153	u32 ind = (u32) index;
	154	struct tmem_oid oid = (struct tmem_oid )&key;
	155	unsigned long pfn = page_to_pfn(page);
	156
	157	if (pool < 0)
	158	return;
	159	if (ind != index)
	160	return;
	161	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	162	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
	163	}
	164
	165	static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
	166	pgoff_t index, struct page *page)
	167	{
	168	u32 ind = (u32) index;
	169	struct tmem_oid oid = (struct tmem_oid )&key;
	170	unsigned long pfn = page_to_pfn(page);
	171	int ret;
	172
	173	/* translate return values to linux semantics */
	174	if (pool < 0)
	175	return -1;
	176	if (ind != index)
	177	return -1;
	178	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	179	if (ret == 1)
	180	return 0;
	181	else
	182	return -1;
	183	}
	184
	185	static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
	186	pgoff_t index)
	187	{
	188	u32 ind = (u32) index;
	189	struct tmem_oid oid = (struct tmem_oid )&key;
	190
	191	if (pool < 0)
	192	return;
	193	if (ind != index)
	194	return;
	195	(void)xen_tmem_flush_page((u32)pool, oid, ind);
	196	}
	197
	198	static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
	199	{
	200	struct tmem_oid oid = (struct tmem_oid )&key;
	201
	202	if (pool < 0)
	203	return;
	204	(void)xen_tmem_flush_object((u32)pool, oid);
	205	}
	206
	207	static void tmem_cleancache_flush_fs(int pool)
	208	{
	209	if (pool < 0)
	210	return;
	211	(void)xen_tmem_destroy_pool((u32)pool);
212	}
213
214	static int tmem_cleancache_init_fs(size_t pagesize)
215	{
216	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
217
218	return xen_tmem_new_pool(uuid_private, 0, pagesize);
219	}
220
221	static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
222	{
223	struct tmem_pool_uuid shared_uuid;
224
225	shared_uuid.uuid_lo = (u64 )uuid;
226	shared_uuid.uuid_hi = (u64 )(&uuid[8]);
227	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
228	}
229
8e6f7c23	230	static bool __initdata use_cleancache = true;
5bc20fc5 DM	231
	232	static int __init no_cleancache(char *s)
	233	{
8e6f7c23	234	use_cleancache = false;
5bc20fc5 DM	235	return 1;
5bc20fc5 DM	236	}
5bc20fc5 DM	237	__setup("nocleancache", no_cleancache);
5bc20fc5 DM	238
8e6f7c23	239	static struct cleancache_ops __initdata tmem_cleancache_ops = {
5bc20fc5 DM	240	.put_page = tmem_cleancache_put_page,
5bc20fc5 DM	241	.get_page = tmem_cleancache_get_page,
91c6cc9b DM	242	.invalidate_page = tmem_cleancache_flush_page,
	243	.invalidate_inode = tmem_cleancache_flush_inode,
	244	.invalidate_fs = tmem_cleancache_flush_fs,
5bc20fc5 DM	245	.init_shared_fs = tmem_cleancache_init_shared_fs,
	246	.init_fs = tmem_cleancache_init_fs
	247	};
afec6e04	248	#endif
5bc20fc5	249
afec6e04 DM	250	#ifdef CONFIG_FRONTSWAP
	251	/* frontswap tmem operations */
	252
	253	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	254	static int tmem_frontswap_poolid;
	255
	256	/*
	257	* Swizzling increases objects per swaptype, increasing tmem concurrency
	258	* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
	259	*/
	260	#define SWIZ_BITS 4
	261	#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
	262	#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) \| (_ind & SWIZ_MASK))
	263	#define iswiz(_ind) (_ind >> SWIZ_BITS)
	264
	265	static inline struct tmem_oid oswiz(unsigned type, u32 ind)
5bc20fc5	266	{
afec6e04 DM	267	struct tmem_oid oid = { .oid = { 0 } };
	268	oid.oid[0] = _oswiz(type, ind);
	269	return oid;
	270	}
5bc20fc5	271
afec6e04	272	/* returns 0 if the page was successfully put into frontswap, -1 if not */
165c8aed	273	static int tmem_frontswap_store(unsigned type, pgoff_t offset,
afec6e04 DM	274	struct page *page)
	275	{
	276	u64 ind64 = (u64)offset;
	277	u32 ind = (u32)offset;
	278	unsigned long pfn = page_to_pfn(page);
	279	int pool = tmem_frontswap_poolid;
	280	int ret;
	281
	282	if (pool < 0)
	283	return -1;
	284	if (ind64 != ind)
	285	return -1;
	286	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	287	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	288	/* translate Xen tmem return values to linux semantics */
	289	if (ret == 1)
	290	return 0;
	291	else
	292	return -1;
	293	}
	294
	295	/*
	296	* returns 0 if the page was successfully gotten from frontswap, -1 if
	297	* was not present (should never happen!)
	298	*/
165c8aed	299	static int tmem_frontswap_load(unsigned type, pgoff_t offset,
afec6e04 DM	300	struct page *page)
	301	{
	302	u64 ind64 = (u64)offset;
	303	u32 ind = (u32)offset;
	304	unsigned long pfn = page_to_pfn(page);
	305	int pool = tmem_frontswap_poolid;
	306	int ret;
	307
	308	if (pool < 0)
	309	return -1;
	310	if (ind64 != ind)
	311	return -1;
	312	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	313	/* translate Xen tmem return values to linux semantics */
	314	if (ret == 1)
	315	return 0;
	316	else
	317	return -1;
	318	}
	319
	320	/* flush a single page from frontswap */
	321	static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
	322	{
	323	u64 ind64 = (u64)offset;
	324	u32 ind = (u32)offset;
	325	int pool = tmem_frontswap_poolid;
	326
	327	if (pool < 0)
	328	return;
	329	if (ind64 != ind)
	330	return;
	331	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
	332	}
	333
	334	/* flush all pages from the passed swaptype */
	335	static void tmem_frontswap_flush_area(unsigned type)
	336	{
	337	int pool = tmem_frontswap_poolid;
	338	int ind;
	339
	340	if (pool < 0)
	341	return;
	342	for (ind = SWIZ_MASK; ind >= 0; ind--)
	343	(void)xen_tmem_flush_object(pool, oswiz(type, ind));
	344	}
	345
	346	static void tmem_frontswap_init(unsigned ignored)
	347	{
	348	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
	349
	350	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	351	if (tmem_frontswap_poolid < 0)
	352	tmem_frontswap_poolid =
	353	xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
	354	}
	355
8e6f7c23	356	static bool __initdata use_frontswap = true;
afec6e04 DM	357
	358	static int __init no_frontswap(char *s)
	359	{
8e6f7c23	360	use_frontswap = false;
afec6e04 DM	361	return 1;
afec6e04 DM	362	}
afec6e04 DM	363	__setup("nofrontswap", no_frontswap);
afec6e04 DM	364
1e01c968	365	static struct frontswap_ops tmem_frontswap_ops = {
165c8aed KRW	366	.store = tmem_frontswap_store,
165c8aed KRW	367	.load = tmem_frontswap_load,
91c6cc9b DM	368	.invalidate_page = tmem_frontswap_flush_page,
91c6cc9b DM	369	.invalidate_area = tmem_frontswap_flush_area,
afec6e04 DM	370	.init = tmem_frontswap_init
	371	};
	372	#endif
	373
	374	static int __init xen_tmem_init(void)
	375	{
5bc20fc5 DM	376	if (!xen_domain())
5bc20fc5 DM	377	return 0;
afec6e04 DM	378	#ifdef CONFIG_FRONTSWAP
	379	if (tmem_enabled && use_frontswap) {
	380	char *s = "";
1e01c968	381	struct frontswap_ops *old_ops =
afec6e04 DM	382	frontswap_register_ops(&tmem_frontswap_ops);
	383
	384	tmem_frontswap_poolid = -1;
1e01c968	385	if (old_ops)
afec6e04 DM	386	s = " (WARNING: frontswap_ops overridden)";
afec6e04 DM	387	printk(KERN_INFO "frontswap enabled, RAM provided by "
22230c18	388	"Xen Transcendent Memory%s\n", s);
afec6e04 DM	389	}
afec6e04 DM	390	#endif
5bc20fc5 DM	391	#ifdef CONFIG_CLEANCACHE
	392	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
	393	if (tmem_enabled && use_cleancache) {
	394	char *s = "";
afec6e04 DM	395	struct cleancache_ops old_ops =
afec6e04 DM	396	cleancache_register_ops(&tmem_cleancache_ops);
5bc20fc5 DM	397	if (old_ops.init_fs != NULL)
	398	s = " (WARNING: cleancache_ops overridden)";
	399	printk(KERN_INFO "cleancache enabled, RAM provided by "
	400	"Xen Transcendent Memory%s\n", s);
	401	}
	402	#endif
	403	return 0;
	404	}
	405
	406	module_init(xen_tmem_init)