[deliverable/linux.git] / drivers / block / xen-blkback / common.h

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#ifndef __XEN_BLKIF__BACKEND__COMMON_H__
#define __XEN_BLKIF__BACKEND__COMMON_H__

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/io.h>
#include <asm/setup.h>
#include <asm/pgalloc.h>
#include <asm/hypervisor.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>
#include <xen/interface/io/ring.h>
#include <xen/interface/io/blkif.h>
#include <xen/interface/io/protocols.h>

#define DRV_PFX "xen-blkback:"
#define DPRINTK(fmt, args...)				\
	pr_debug(DRV_PFX "(%s:%d) " fmt ".\n",		\
		 __func__, __LINE__, ##args)


/* Not a real protocol.  Used to generate ring structs which contain
 * the elements common to all protocols only.  This way we get a
 * compiler-checkable way to use common struct elements, so we can
 * avoid using switch(protocol) in a number of places.  */
struct blkif_common_request {
	char dummy;
};
struct blkif_common_response {
	char dummy;
};

struct blkif_x86_32_request_rw {
	uint8_t        nr_segments;  /* number of segments                   */
	blkif_vdev_t   handle;       /* only for read/write requests         */
	uint64_t       id;           /* private guest value, echoed in resp  */
	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
} __attribute__((__packed__));

struct blkif_x86_32_request_discard {
	uint8_t        flag;         /* BLKIF_DISCARD_SECURE or zero         */
	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */
	uint64_t       id;           /* private guest value, echoed in resp  */
	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
	uint64_t       nr_sectors;
} __attribute__((__packed__));

struct blkif_x86_32_request {
	uint8_t        operation;    /* BLKIF_OP_???                         */
	union {
		struct blkif_x86_32_request_rw rw;
		struct blkif_x86_32_request_discard discard;
	} u;
} __attribute__((__packed__));

/* i386 protocol version */
#pragma pack(push, 4)
struct blkif_x86_32_response {
	uint64_t        id;              /* copied from request */
	uint8_t         operation;       /* copied from request */
	int16_t         status;          /* BLKIF_RSP_???       */
};
#pragma pack(pop)
/* x86_64 protocol version */

struct blkif_x86_64_request_rw {
	uint8_t        nr_segments;  /* number of segments                   */
	blkif_vdev_t   handle;       /* only for read/write requests         */
	uint32_t       _pad1;        /* offsetof(blkif_reqest..,u.rw.id)==8  */
	uint64_t       id;
	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
} __attribute__((__packed__));

struct blkif_x86_64_request_discard {
	uint8_t        flag;         /* BLKIF_DISCARD_SECURE or zero         */
	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */
        uint32_t       _pad2;        /* offsetof(blkif_..,u.discard.id)==8   */
	uint64_t       id;
	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
	uint64_t       nr_sectors;
} __attribute__((__packed__));

struct blkif_x86_64_request {
	uint8_t        operation;    /* BLKIF_OP_???                         */
	union {
		struct blkif_x86_64_request_rw rw;
		struct blkif_x86_64_request_discard discard;
	} u;
} __attribute__((__packed__));

struct blkif_x86_64_response {
	uint64_t       __attribute__((__aligned__(8))) id;
	uint8_t         operation;       /* copied from request */
	int16_t         status;          /* BLKIF_RSP_???       */
};

DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
		  struct blkif_common_response);
DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
		  struct blkif_x86_32_response);
DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
		  struct blkif_x86_64_response);

union blkif_back_rings {
	struct blkif_back_ring        native;
	struct blkif_common_back_ring common;
	struct blkif_x86_32_back_ring x86_32;
	struct blkif_x86_64_back_ring x86_64;
};

enum blkif_protocol {
	BLKIF_PROTOCOL_NATIVE = 1,
	BLKIF_PROTOCOL_X86_32 = 2,
	BLKIF_PROTOCOL_X86_64 = 3,
};

struct xen_vbd {
	/* What the domain refers to this vbd as. */
	blkif_vdev_t		handle;
	/* Non-zero -> read-only */
	unsigned char		readonly;
	/* VDISK_xxx */
	unsigned char		type;
	/* phys device that this vbd maps to. */
	u32			pdevice;
	struct block_device	*bdev;
	/* Cached size parameter. */
	sector_t		size;
	bool			flush_support;
	bool			discard_secure;
};

struct backend_info;

struct xen_blkif {
	/* Unique identifier for this interface. */
	domid_t			domid;
	unsigned int		handle;
	/* Physical parameters of the comms window. */
	unsigned int		irq;
	/* Comms information. */
	enum blkif_protocol	blk_protocol;
	union blkif_back_rings	blk_rings;
	void			*blk_ring;
	/* The VBD attached to this interface. */
	struct xen_vbd		vbd;
	/* Back pointer to the backend_info. */
	struct backend_info	*be;
	/* Private fields. */
	spinlock_t		blk_ring_lock;
	atomic_t		refcnt;

	wait_queue_head_t	wq;
	/* for barrier (drain) requests */
	struct completion	drain_complete;
	atomic_t		drain;
	/* One thread per one blkif. */
	struct task_struct	*xenblkd;
	unsigned int		waiting_reqs;

	/* statistics */
	unsigned long		st_print;
	int			st_rd_req;
	int			st_wr_req;
	int			st_oo_req;
	int			st_f_req;
	int			st_ds_req;
	int			st_rd_sect;
	int			st_wr_sect;

	wait_queue_head_t	waiting_to_free;
};


#define vbd_sz(_v)	((_v)->bdev->bd_part ? \
			 (_v)->bdev->bd_part->nr_sects : \
			  get_capacity((_v)->bdev->bd_disk))

#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
#define xen_blkif_put(_b)				\
	do {						\
		if (atomic_dec_and_test(&(_b)->refcnt))	\
			wake_up(&(_b)->waiting_to_free);\
	} while (0)

struct phys_req {
	unsigned short		dev;
	blkif_sector_t		nr_sects;
	struct block_device	*bdev;
	blkif_sector_t		sector_number;
};
int xen_blkif_interface_init(void);

int xen_blkif_xenbus_init(void);

irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
int xen_blkif_schedule(void *arg);

int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
			      struct backend_info *be, int state);

int xen_blkbk_barrier(struct xenbus_transaction xbt,
		      struct backend_info *be, int state);
struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);

static inline void blkif_get_x86_32_req(struct blkif_request *dst,
					struct blkif_x86_32_request *src)
{
	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
	dst->operation = src->operation;
	switch (src->operation) {
	case BLKIF_OP_READ:
	case BLKIF_OP_WRITE:
	case BLKIF_OP_WRITE_BARRIER:
	case BLKIF_OP_FLUSH_DISKCACHE:
		dst->u.rw.nr_segments = src->u.rw.nr_segments;
		dst->u.rw.handle = src->u.rw.handle;
		dst->u.rw.id = src->u.rw.id;
		dst->u.rw.sector_number = src->u.rw.sector_number;
		barrier();
		if (n > dst->u.rw.nr_segments)
			n = dst->u.rw.nr_segments;
		for (i = 0; i < n; i++)
			dst->u.rw.seg[i] = src->u.rw.seg[i];
		break;
	case BLKIF_OP_DISCARD:
		dst->u.discard.flag = src->u.discard.flag;
		dst->u.discard.id = src->u.discard.id;
		dst->u.discard.sector_number = src->u.discard.sector_number;
		dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
		break;
	default:
		break;
	}
}

static inline void blkif_get_x86_64_req(struct blkif_request *dst,
					struct blkif_x86_64_request *src)
{
	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
	dst->operation = src->operation;
	switch (src->operation) {
	case BLKIF_OP_READ:
	case BLKIF_OP_WRITE:
	case BLKIF_OP_WRITE_BARRIER:
	case BLKIF_OP_FLUSH_DISKCACHE:
		dst->u.rw.nr_segments = src->u.rw.nr_segments;
		dst->u.rw.handle = src->u.rw.handle;
		dst->u.rw.id = src->u.rw.id;
		dst->u.rw.sector_number = src->u.rw.sector_number;
		barrier();
		if (n > dst->u.rw.nr_segments)
			n = dst->u.rw.nr_segments;
		for (i = 0; i < n; i++)
			dst->u.rw.seg[i] = src->u.rw.seg[i];
		break;
	case BLKIF_OP_DISCARD:
		dst->u.discard.flag = src->u.discard.flag;
		dst->u.discard.id = src->u.discard.id;
		dst->u.discard.sector_number = src->u.discard.sector_number;
		dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
		break;
	default:
		break;
	}
}

#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */
Commit	Line	Data
4d05a28d KRW	1	/*
	2	* This program is free software; you can redistribute it and/or
	3	* modify it under the terms of the GNU General Public License version 2
	4	* as published by the Free Software Foundation; or, when distributed
	5	* separately from the Linux kernel or incorporated into other
	6	* software packages, subject to the following license:
	7	*
	8	* Permission is hereby granted, free of charge, to any person obtaining a copy
	9	* of this source file (the "Software"), to deal in the Software without
	10	* restriction, including without limitation the rights to use, copy, modify,
	11	* merge, publish, distribute, sublicense, and/or sell copies of the Software,
	12	* and to permit persons to whom the Software is furnished to do so, subject to
	13	* the following conditions:
	14	*
	15	* The above copyright notice and this permission notice shall be included in
	16	* all copies or substantial portions of the Software.
	17	*
	18	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	19	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	20	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	21	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	22	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	23	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	24	* IN THE SOFTWARE.
	25	*/
	26
5a577e38 KRW	27	#ifndef __XEN_BLKIF__BACKEND__COMMON_H__
5a577e38 KRW	28	#define __XEN_BLKIF__BACKEND__COMMON_H__
4d05a28d	29
4d05a28d KRW	30	#include <linux/module.h>
	31	#include <linux/interrupt.h>
	32	#include <linux/slab.h>
	33	#include <linux/blkdev.h>
	34	#include <linux/vmalloc.h>
	35	#include <linux/wait.h>
5489377c	36	#include <linux/io.h>
4d05a28d KRW	37	#include <asm/setup.h>
4d05a28d KRW	38	#include <asm/pgalloc.h>
4d05a28d	39	#include <asm/hypervisor.h>
88122933	40	#include <xen/grant_table.h>
4d05a28d	41	#include <xen/xenbus.h>
452a6b2b KRW	42	#include <xen/interface/io/ring.h>
	43	#include <xen/interface/io/blkif.h>
	44	#include <xen/interface/io/protocols.h>
4d05a28d	45
22b20f2d	46	#define DRV_PFX "xen-blkback:"
1afbd730	47	#define DPRINTK(fmt, args...) \
1bc05b0a	48	pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
1afbd730	49	__func__, __LINE__, ##args)
4d05a28d	50
452a6b2b KRW	51
	52	/* Not a real protocol. Used to generate ring structs which contain
	53	* the elements common to all protocols only. This way we get a
	54	* compiler-checkable way to use common struct elements, so we can
	55	* avoid using switch(protocol) in a number of places. */
	56	struct blkif_common_request {
	57	char dummy;
	58	};
	59	struct blkif_common_response {
	60	char dummy;
	61	};
	62
b3cb0d6a	63	struct blkif_x86_32_request_rw {
97e36834 KRW	64	uint8_t nr_segments; /* number of segments */
	65	blkif_vdev_t handle; /* only for read/write requests */
	66	uint64_t id; /* private guest value, echoed in resp */
b3cb0d6a LD	67	blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
b3cb0d6a LD	68	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
97e36834	69	} __attribute__((__packed__));
b3cb0d6a LD	70
b3cb0d6a LD	71	struct blkif_x86_32_request_discard {
5ea42986	72	uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
97e36834 KRW	73	blkif_vdev_t _pad1; /* was "handle" for read/write requests */
97e36834 KRW	74	uint64_t id; /* private guest value, echoed in resp */
b3cb0d6a	75	blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
97e36834 KRW	76	uint64_t nr_sectors;
97e36834 KRW	77	} __attribute__((__packed__));
b3cb0d6a	78
452a6b2b KRW	79	struct blkif_x86_32_request {
452a6b2b KRW	80	uint8_t operation; /* BLKIF_OP_??? */
b3cb0d6a LD	81	union {
	82	struct blkif_x86_32_request_rw rw;
	83	struct blkif_x86_32_request_discard discard;
	84	} u;
97e36834 KRW	85	} __attribute__((__packed__));
	86
	87	/* i386 protocol version */
	88	#pragma pack(push, 4)
452a6b2b KRW	89	struct blkif_x86_32_response {
	90	uint64_t id; /* copied from request */
	91	uint8_t operation; /* copied from request */
	92	int16_t status; /* BLKIF_RSP_??? */
	93	};
452a6b2b	94	#pragma pack(pop)
452a6b2b	95	/* x86_64 protocol version */
b3cb0d6a LD	96
b3cb0d6a LD	97	struct blkif_x86_64_request_rw {
97e36834 KRW	98	uint8_t nr_segments; /* number of segments */
	99	blkif_vdev_t handle; /* only for read/write requests */
	100	uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */
	101	uint64_t id;
b3cb0d6a LD	102	blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
b3cb0d6a LD	103	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
97e36834	104	} __attribute__((__packed__));
b3cb0d6a LD	105
b3cb0d6a LD	106	struct blkif_x86_64_request_discard {
5ea42986	107	uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
97e36834 KRW	108	blkif_vdev_t _pad1; /* was "handle" for read/write requests */
	109	uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
	110	uint64_t id;
b3cb0d6a	111	blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
97e36834 KRW	112	uint64_t nr_sectors;
97e36834 KRW	113	} __attribute__((__packed__));
b3cb0d6a	114
452a6b2b KRW	115	struct blkif_x86_64_request {
452a6b2b KRW	116	uint8_t operation; /* BLKIF_OP_??? */
b3cb0d6a LD	117	union {
	118	struct blkif_x86_64_request_rw rw;
	119	struct blkif_x86_64_request_discard discard;
	120	} u;
97e36834 KRW	121	} __attribute__((__packed__));
97e36834 KRW	122
452a6b2b KRW	123	struct blkif_x86_64_response {
	124	uint64_t __attribute__((__aligned__(8))) id;
	125	uint8_t operation; /* copied from request */
	126	int16_t status; /* BLKIF_RSP_??? */
	127	};
452a6b2b KRW	128
	129	DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
	130	struct blkif_common_response);
	131	DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
	132	struct blkif_x86_32_response);
	133	DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
	134	struct blkif_x86_64_response);
	135
	136	union blkif_back_rings {
	137	struct blkif_back_ring native;
	138	struct blkif_common_back_ring common;
	139	struct blkif_x86_32_back_ring x86_32;
	140	struct blkif_x86_64_back_ring x86_64;
	141	};
	142
	143	enum blkif_protocol {
	144	BLKIF_PROTOCOL_NATIVE = 1,
	145	BLKIF_PROTOCOL_X86_32 = 2,
	146	BLKIF_PROTOCOL_X86_64 = 3,
	147	};
	148
3d814731	149	struct xen_vbd {
01f37f2d KRW	150	/* What the domain refers to this vbd as. */
	151	blkif_vdev_t handle;
	152	/* Non-zero -> read-only */
	153	unsigned char readonly;
	154	/* VDISK_xxx */
	155	unsigned char type;
	156	/* phys device that this vbd maps to. */
	157	u32 pdevice;
	158	struct block_device *bdev;
	159	/* Cached size parameter. */
	160	sector_t size;
	161	bool flush_support;
5ea42986	162	bool discard_secure;
4d05a28d KRW	163	};
	164
	165	struct backend_info;
	166
30fd1502	167	struct xen_blkif {
4d05a28d	168	/* Unique identifier for this interface. */
01f37f2d KRW	169	domid_t domid;
01f37f2d KRW	170	unsigned int handle;
4d05a28d	171	/* Physical parameters of the comms window. */
01f37f2d	172	unsigned int irq;
4d05a28d	173	/* Comms information. */
01f37f2d KRW	174	enum blkif_protocol blk_protocol;
01f37f2d KRW	175	union blkif_back_rings blk_rings;
2d073846	176	void *blk_ring;
4d05a28d	177	/* The VBD attached to this interface. */
3d814731	178	struct xen_vbd vbd;
4d05a28d	179	/* Back pointer to the backend_info. */
01f37f2d	180	struct backend_info *be;
4d05a28d	181	/* Private fields. */
01f37f2d KRW	182	spinlock_t blk_ring_lock;
01f37f2d KRW	183	atomic_t refcnt;
4d05a28d	184
01f37f2d	185	wait_queue_head_t wq;
29bde093 KRW	186	/* for barrier (drain) requests */
	187	struct completion drain_complete;
	188	atomic_t drain;
a1397fa3	189	/* One thread per one blkif. */
01f37f2d KRW	190	struct task_struct *xenblkd;
01f37f2d KRW	191	unsigned int waiting_reqs;
4d05a28d KRW	192
4d05a28d KRW	193	/* statistics */
01f37f2d KRW	194	unsigned long st_print;
	195	int st_rd_req;
	196	int st_wr_req;
	197	int st_oo_req;
	198	int st_f_req;
b3cb0d6a	199	int st_ds_req;
01f37f2d KRW	200	int st_rd_sect;
	201	int st_wr_sect;
	202
	203	wait_queue_head_t waiting_to_free;
5489377c	204	};
4d05a28d	205
42c7841d KRW	206
	207	#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
	208	(_v)->bdev->bd_part->nr_sects : \
	209	get_capacity((_v)->bdev->bd_disk))
4d05a28d	210
8b6bf747 KRW	211	#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
8b6bf747 KRW	212	#define xen_blkif_put(_b) \
4d05a28d KRW	213	do { \
	214	if (atomic_dec_and_test(&(_b)->refcnt)) \
	215	wake_up(&(_b)->waiting_to_free);\
	216	} while (0)
	217
4d05a28d	218	struct phys_req {
01f37f2d	219	unsigned short dev;
b3cb0d6a	220	blkif_sector_t nr_sects;
01f37f2d KRW	221	struct block_device *bdev;
01f37f2d KRW	222	blkif_sector_t sector_number;
4d05a28d	223	};
8b6bf747	224	int xen_blkif_interface_init(void);
4d05a28d	225
8b6bf747	226	int xen_blkif_xenbus_init(void);
4d05a28d	227
8b6bf747 KRW	228	irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
8b6bf747 KRW	229	int xen_blkif_schedule(void *arg);
4d05a28d	230
24f567f9 KRW	231	int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
24f567f9 KRW	232	struct backend_info *be, int state);
4d05a28d	233
29bde093 KRW	234	int xen_blkbk_barrier(struct xenbus_transaction xbt,
29bde093 KRW	235	struct backend_info *be, int state);
8b6bf747	236	struct xenbus_device xen_blkbk_xenbus(struct backend_info be);
98e036a3	237
b0f80127	238	static inline void blkif_get_x86_32_req(struct blkif_request *dst,
68c88dd7 KRW	239	struct blkif_x86_32_request *src)
	240	{
	241	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
	242	dst->operation = src->operation;
b3cb0d6a LD	243	switch (src->operation) {
	244	case BLKIF_OP_READ:
	245	case BLKIF_OP_WRITE:
	246	case BLKIF_OP_WRITE_BARRIER:
	247	case BLKIF_OP_FLUSH_DISKCACHE:
97e36834 KRW	248	dst->u.rw.nr_segments = src->u.rw.nr_segments;
	249	dst->u.rw.handle = src->u.rw.handle;
	250	dst->u.rw.id = src->u.rw.id;
b3cb0d6a LD	251	dst->u.rw.sector_number = src->u.rw.sector_number;
b3cb0d6a LD	252	barrier();
97e36834 KRW	253	if (n > dst->u.rw.nr_segments)
97e36834 KRW	254	n = dst->u.rw.nr_segments;
b3cb0d6a LD	255	for (i = 0; i < n; i++)
	256	dst->u.rw.seg[i] = src->u.rw.seg[i];
	257	break;
	258	case BLKIF_OP_DISCARD:
5ea42986	259	dst->u.discard.flag = src->u.discard.flag;
8c9ce606	260	dst->u.discard.id = src->u.discard.id;
b3cb0d6a LD	261	dst->u.discard.sector_number = src->u.discard.sector_number;
	262	dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
	263	break;
	264	default:
	265	break;
	266	}
68c88dd7 KRW	267	}
68c88dd7 KRW	268
b0f80127	269	static inline void blkif_get_x86_64_req(struct blkif_request *dst,
68c88dd7 KRW	270	struct blkif_x86_64_request *src)
	271	{
	272	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
	273	dst->operation = src->operation;
b3cb0d6a LD	274	switch (src->operation) {
	275	case BLKIF_OP_READ:
	276	case BLKIF_OP_WRITE:
	277	case BLKIF_OP_WRITE_BARRIER:
	278	case BLKIF_OP_FLUSH_DISKCACHE:
97e36834 KRW	279	dst->u.rw.nr_segments = src->u.rw.nr_segments;
	280	dst->u.rw.handle = src->u.rw.handle;
	281	dst->u.rw.id = src->u.rw.id;
b3cb0d6a LD	282	dst->u.rw.sector_number = src->u.rw.sector_number;
b3cb0d6a LD	283	barrier();
97e36834 KRW	284	if (n > dst->u.rw.nr_segments)
97e36834 KRW	285	n = dst->u.rw.nr_segments;
b3cb0d6a LD	286	for (i = 0; i < n; i++)
	287	dst->u.rw.seg[i] = src->u.rw.seg[i];
	288	break;
	289	case BLKIF_OP_DISCARD:
5ea42986	290	dst->u.discard.flag = src->u.discard.flag;
8c9ce606	291	dst->u.discard.id = src->u.discard.id;
b3cb0d6a LD	292	dst->u.discard.sector_number = src->u.discard.sector_number;
	293	dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
	294	break;
	295	default:
	296	break;
	297	}
68c88dd7 KRW	298	}
68c88dd7 KRW	299
5a577e38	300	#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */