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 __BLKIF__BACKEND__COMMON_H__
#define __BLKIF__BACKEND__COMMON_H__

#include <linux/version.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/blkif.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>

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

struct 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;
};

struct backend_info;

struct blkif_st {
	/* 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;
	struct vm_struct	*blk_ring_area;
	/* The VBD attached to this interface. */
	struct 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;
	/* 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_rd_sect;
	int			st_wr_sect;

	wait_queue_head_t	waiting_to_free;

	grant_handle_t		shmem_handle;
	grant_ref_t		shmem_ref;
};


#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;
	unsigned short		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);

struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);

static void inline 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;
	dst->nr_segments = src->nr_segments;
	dst->handle = src->handle;
	dst->id = src->id;
	dst->u.rw.sector_number = src->sector_number;
	barrier();
	if (n > dst->nr_segments)
		n = dst->nr_segments;
	for (i = 0; i < n; i++)
		dst->u.rw.seg[i] = src->seg[i];
}

static void inline 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;
	dst->nr_segments = src->nr_segments;
	dst->handle = src->handle;
	dst->id = src->id;
	dst->u.rw.sector_number = src->sector_number;
	barrier();
	if (n > dst->nr_segments)
		n = dst->nr_segments;
	for (i = 0; i < n; i++)
		dst->u.rw.seg[i] = src->seg[i];
}

#endif /* __BLKIF__BACKEND__COMMON_H__ */