xen-scsiback.c 47.9 KB
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/*
 * Xen SCSI backend driver
 *
 * Copyright (c) 2008, FUJITSU Limited
 *
 * Based on the blkback driver code.
 * Adaption to kernel taget core infrastructure taken from vhost/scsi.c
 *
 * 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.
 */

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#define pr_fmt(fmt) "xen-pvscsi: " fmt

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#include <stdarg.h>

#include <linux/module.h>
#include <linux/utsname.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/configfs.h>

#include <generated/utsrelease.h>

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#include <scsi/scsi.h>
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#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_fabric_configfs.h>

#include <asm/hypervisor.h>

#include <xen/xen.h>
#include <xen/balloon.h>
#include <xen/events.h>
#include <xen/xenbus.h>
#include <xen/grant_table.h>
#include <xen/page.h>

#include <xen/interface/grant_table.h>
#include <xen/interface/io/vscsiif.h>

#define VSCSI_VERSION	"v0.1"
#define VSCSI_NAMELEN	32

struct ids_tuple {
	unsigned int hst;		/* host    */
	unsigned int chn;		/* channel */
	unsigned int tgt;		/* target  */
	unsigned int lun;		/* LUN     */
};

struct v2p_entry {
	struct ids_tuple v;		/* translate from */
	struct scsiback_tpg *tpg;	/* translate to   */
	unsigned int lun;
	struct kref kref;
	struct list_head l;
};

struct vscsibk_info {
	struct xenbus_device *dev;

	domid_t domid;
	unsigned int irq;

	struct vscsiif_back_ring ring;
	int ring_error;

	spinlock_t ring_lock;
	atomic_t nr_unreplied_reqs;

	spinlock_t v2p_lock;
	struct list_head v2p_entry_lists;

	wait_queue_head_t waiting_to_free;
};

/* theoretical maximum of grants for one request */
#define VSCSI_MAX_GRANTS	(SG_ALL + VSCSIIF_SG_TABLESIZE)

/*
 * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 * call to map/unmap grants. Don't choose it too large, as there are arrays
 * with VSCSI_GRANT_BATCH elements allocated on the stack.
 */
#define VSCSI_GRANT_BATCH	16

struct vscsibk_pend {
	uint16_t rqid;

	uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
	uint8_t cmd_len;

	uint8_t sc_data_direction;
	uint16_t n_sg;		/* real length of SG list */
	uint16_t n_grants;	/* SG pages and potentially SG list */
	uint32_t data_len;
	uint32_t result;

	struct vscsibk_info *info;
	struct v2p_entry *v2p;
	struct scatterlist *sgl;

	uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];

	grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
	struct page *pages[VSCSI_MAX_GRANTS];

	struct se_cmd se_cmd;
};

struct scsiback_tmr {
	atomic_t tmr_complete;
	wait_queue_head_t tmr_wait;
};

struct scsiback_nexus {
	/* Pointer to TCM session for I_T Nexus */
	struct se_session *tvn_se_sess;
};

struct scsiback_tport {
	/* SCSI protocol the tport is providing */
	u8 tport_proto_id;
	/* Binary World Wide unique Port Name for pvscsi Target port */
	u64 tport_wwpn;
	/* ASCII formatted WWPN for pvscsi Target port */
	char tport_name[VSCSI_NAMELEN];
	/* Returned by scsiback_make_tport() */
	struct se_wwn tport_wwn;
};

struct scsiback_tpg {
	/* scsiback port target portal group tag for TCM */
	u16 tport_tpgt;
	/* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
	int tv_tpg_port_count;
	/* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
	int tv_tpg_fe_count;
	/* list for scsiback_list */
	struct list_head tv_tpg_list;
	/* Used to protect access for tpg_nexus */
	struct mutex tv_tpg_mutex;
	/* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
	struct scsiback_nexus *tpg_nexus;
	/* Pointer back to scsiback_tport */
	struct scsiback_tport *tport;
	/* Returned by scsiback_make_tpg() */
	struct se_portal_group se_tpg;
	/* alias used in xenstore */
	char param_alias[VSCSI_NAMELEN];
	/* list of info structures related to this target portal group */
	struct list_head info_list;
};

#define SCSIBACK_INVALID_HANDLE (~0)

static bool log_print_stat;
module_param(log_print_stat, bool, 0644);

static int scsiback_max_buffer_pages = 1024;
module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
MODULE_PARM_DESC(max_buffer_pages,
"Maximum number of free pages to keep in backend buffer");

static struct kmem_cache *scsiback_cachep;
static DEFINE_SPINLOCK(free_pages_lock);
static int free_pages_num;
static LIST_HEAD(scsiback_free_pages);

/* Global spinlock to protect scsiback TPG list */
static DEFINE_MUTEX(scsiback_mutex);
static LIST_HEAD(scsiback_list);

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static const struct target_core_fabric_ops scsiback_ops;
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static void scsiback_get(struct vscsibk_info *info)
{
	atomic_inc(&info->nr_unreplied_reqs);
}

static void scsiback_put(struct vscsibk_info *info)
{
	if (atomic_dec_and_test(&info->nr_unreplied_reqs))
		wake_up(&info->waiting_to_free);
}

static void put_free_pages(struct page **page, int num)
{
	unsigned long flags;
	int i = free_pages_num + num, n = num;

	if (num == 0)
		return;
	if (i > scsiback_max_buffer_pages) {
		n = min(num, i - scsiback_max_buffer_pages);
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		gnttab_free_pages(n, page + num - n);
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		n = num - n;
	}
	spin_lock_irqsave(&free_pages_lock, flags);
	for (i = 0; i < n; i++)
		list_add(&page[i]->lru, &scsiback_free_pages);
	free_pages_num += n;
	spin_unlock_irqrestore(&free_pages_lock, flags);
}

static int get_free_page(struct page **page)
{
	unsigned long flags;

	spin_lock_irqsave(&free_pages_lock, flags);
	if (list_empty(&scsiback_free_pages)) {
		spin_unlock_irqrestore(&free_pages_lock, flags);
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		return gnttab_alloc_pages(1, page);
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	}
	page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
	list_del(&page[0]->lru);
	free_pages_num--;
	spin_unlock_irqrestore(&free_pages_lock, flags);
	return 0;
}

static unsigned long vaddr_page(struct page *page)
{
	unsigned long pfn = page_to_pfn(page);

	return (unsigned long)pfn_to_kaddr(pfn);
}

static unsigned long vaddr(struct vscsibk_pend *req, int seg)
{
	return vaddr_page(req->pages[seg]);
}

static void scsiback_print_status(char *sense_buffer, int errors,
					struct vscsibk_pend *pending_req)
{
	struct scsiback_tpg *tpg = pending_req->v2p->tpg;

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	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
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	       tpg->tport->tport_name, pending_req->v2p->lun,
	       pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
	       host_byte(errors), driver_byte(errors));
}

static void scsiback_fast_flush_area(struct vscsibk_pend *req)
{
	struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
	struct page *pages[VSCSI_GRANT_BATCH];
	unsigned int i, invcount = 0;
	grant_handle_t handle;
	int err;

	kfree(req->sgl);
	req->sgl = NULL;
	req->n_sg = 0;

	if (!req->n_grants)
		return;

	for (i = 0; i < req->n_grants; i++) {
		handle = req->grant_handles[i];
		if (handle == SCSIBACK_INVALID_HANDLE)
			continue;
		gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
				    GNTMAP_host_map, handle);
		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
		pages[invcount] = req->pages[i];
		put_page(pages[invcount]);
		invcount++;
		if (invcount < VSCSI_GRANT_BATCH)
			continue;
		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
		BUG_ON(err);
		invcount = 0;
	}

	if (invcount) {
		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
		BUG_ON(err);
	}

	put_free_pages(req->pages, req->n_grants);
	req->n_grants = 0;
}

static void scsiback_free_translation_entry(struct kref *kref)
{
	struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
	struct scsiback_tpg *tpg = entry->tpg;

	mutex_lock(&tpg->tv_tpg_mutex);
	tpg->tv_tpg_fe_count--;
	mutex_unlock(&tpg->tv_tpg_mutex);

	kfree(entry);
}

static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
			uint32_t resid, struct vscsibk_pend *pending_req)
{
	struct vscsiif_response *ring_res;
	struct vscsibk_info *info = pending_req->info;
	int notify;
	struct scsi_sense_hdr sshdr;
	unsigned long flags;
	unsigned len;

	spin_lock_irqsave(&info->ring_lock, flags);

	ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
	info->ring.rsp_prod_pvt++;

	ring_res->rslt   = result;
	ring_res->rqid   = pending_req->rqid;

	if (sense_buffer != NULL &&
	    scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
				 &sshdr)) {
		len = min_t(unsigned, 8 + sense_buffer[7],
			    VSCSIIF_SENSE_BUFFERSIZE);
		memcpy(ring_res->sense_buffer, sense_buffer, len);
		ring_res->sense_len = len;
	} else {
		ring_res->sense_len = 0;
	}

	ring_res->residual_len = resid;

	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
	spin_unlock_irqrestore(&info->ring_lock, flags);

	if (notify)
		notify_remote_via_irq(info->irq);

	if (pending_req->v2p)
		kref_put(&pending_req->v2p->kref,
			 scsiback_free_translation_entry);
}

static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
{
	struct vscsibk_info *info = pending_req->info;
	unsigned char *sense_buffer;
	unsigned int resid;
	int errors;

	sense_buffer = pending_req->sense_buffer;
	resid        = pending_req->se_cmd.residual_count;
	errors       = pending_req->result;

	if (errors && log_print_stat)
		scsiback_print_status(sense_buffer, errors, pending_req);

	scsiback_fast_flush_area(pending_req);
	scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
	scsiback_put(info);
}

static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
{
	struct se_cmd *se_cmd = &pending_req->se_cmd;
	struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
	int rc;

	memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);

	memset(se_cmd, 0, sizeof(*se_cmd));

	scsiback_get(pending_req->info);
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	se_cmd->tag = pending_req->rqid;
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	rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
			pending_req->sense_buffer, pending_req->v2p->lun,
			pending_req->data_len, 0,
			pending_req->sc_data_direction, 0,
			pending_req->sgl, pending_req->n_sg,
			NULL, 0, NULL, 0);
	if (rc < 0) {
		transport_send_check_condition_and_sense(se_cmd,
				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
		transport_generic_free_cmd(se_cmd, 0);
	}
}

static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
	struct page **pg, grant_handle_t *grant, int cnt)
{
	int err, i;

	if (!cnt)
		return 0;

	err = gnttab_map_refs(map, NULL, pg, cnt);
	BUG_ON(err);
	for (i = 0; i < cnt; i++) {
		if (unlikely(map[i].status != GNTST_okay)) {
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			pr_err("invalid buffer -- could not remap it\n");
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			map[i].handle = SCSIBACK_INVALID_HANDLE;
			err = -ENOMEM;
		} else {
			get_page(pg[i]);
		}
		grant[i] = map[i].handle;
	}
	return err;
}

static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
			struct scsiif_request_segment *seg, struct page **pg,
			grant_handle_t *grant, int cnt, u32 flags)
{
	int mapcount = 0, i, err = 0;
	struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
	struct vscsibk_info *info = pending_req->info;

	for (i = 0; i < cnt; i++) {
		if (get_free_page(pg + mapcount)) {
			put_free_pages(pg, mapcount);
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			pr_err("no grant page\n");
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			return -ENOMEM;
		}
		gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
				  flags, seg[i].gref, info->domid);
		mapcount++;
		if (mapcount < VSCSI_GRANT_BATCH)
			continue;
		err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
		pg += mapcount;
		grant += mapcount;
		pending_req->n_grants += mapcount;
		if (err)
			return err;
		mapcount = 0;
	}
	err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
	pending_req->n_grants += mapcount;
	return err;
}

static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
					struct vscsibk_pend *pending_req)
{
	u32 flags;
	int i, err, n_segs, i_seg = 0;
	struct page **pg;
	struct scsiif_request_segment *seg;
	unsigned long end_seg = 0;
	unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
	unsigned int nr_sgl = 0;
	struct scatterlist *sg;
	grant_handle_t *grant;

	pending_req->n_sg = 0;
	pending_req->n_grants = 0;
	pending_req->data_len = 0;

	nr_segments &= ~VSCSIIF_SG_GRANT;
	if (!nr_segments)
		return 0;

	if (nr_segments > VSCSIIF_SG_TABLESIZE) {
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		pr_debug("invalid parameter nr_seg = %d\n",
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			ring_req->nr_segments);
		return -EINVAL;
	}

	if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
		err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
			pending_req->pages, pending_req->grant_handles,
			nr_segments, GNTMAP_host_map | GNTMAP_readonly);
		if (err)
			return err;
		nr_sgl = nr_segments;
		nr_segments = 0;
		for (i = 0; i < nr_sgl; i++) {
			n_segs = ring_req->seg[i].length /
				 sizeof(struct scsiif_request_segment);
			if ((unsigned)ring_req->seg[i].offset +
			    (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
			    n_segs * sizeof(struct scsiif_request_segment) !=
			    ring_req->seg[i].length)
				return -EINVAL;
			nr_segments += n_segs;
		}
		if (nr_segments > SG_ALL) {
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			pr_debug("invalid nr_seg = %d\n", nr_segments);
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			return -EINVAL;
		}
	}

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	/* free of (sgl) in fast_flush_area() */
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	pending_req->sgl = kmalloc_array(nr_segments,
					sizeof(struct scatterlist), GFP_KERNEL);
	if (!pending_req->sgl)
		return -ENOMEM;

	sg_init_table(pending_req->sgl, nr_segments);
	pending_req->n_sg = nr_segments;

	flags = GNTMAP_host_map;
	if (pending_req->sc_data_direction == DMA_TO_DEVICE)
		flags |= GNTMAP_readonly;

	pg = pending_req->pages + nr_sgl;
	grant = pending_req->grant_handles + nr_sgl;
	if (!nr_sgl) {
		seg = ring_req->seg;
		err = scsiback_gnttab_data_map_list(pending_req, seg,
			pg, grant, nr_segments, flags);
		if (err)
			return err;
	} else {
		for (i = 0; i < nr_sgl; i++) {
			seg = (struct scsiif_request_segment *)(
			      vaddr(pending_req, i) + ring_req->seg[i].offset);
			n_segs = ring_req->seg[i].length /
				 sizeof(struct scsiif_request_segment);
			err = scsiback_gnttab_data_map_list(pending_req, seg,
				pg, grant, n_segs, flags);
			if (err)
				return err;
			pg += n_segs;
			grant += n_segs;
		}
		end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
		seg = (struct scsiif_request_segment *)end_seg;
		end_seg += ring_req->seg[0].length;
		pg = pending_req->pages + nr_sgl;
	}

	for_each_sg(pending_req->sgl, sg, nr_segments, i) {
		sg_set_page(sg, pg[i], seg->length, seg->offset);
		pending_req->data_len += seg->length;
		seg++;
		if (nr_sgl && (unsigned long)seg >= end_seg) {
			i_seg++;
			end_seg = vaddr(pending_req, i_seg) +
				  ring_req->seg[i_seg].offset;
			seg = (struct scsiif_request_segment *)end_seg;
			end_seg += ring_req->seg[i_seg].length;
		}
		if (sg->offset >= PAGE_SIZE ||
		    sg->length > PAGE_SIZE ||
		    sg->offset + sg->length > PAGE_SIZE)
			return -EINVAL;
	}

	return 0;
}

static void scsiback_disconnect(struct vscsibk_info *info)
{
	wait_event(info->waiting_to_free,
		atomic_read(&info->nr_unreplied_reqs) == 0);

	unbind_from_irqhandler(info->irq, info);
	info->irq = 0;
	xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
}

static void scsiback_device_action(struct vscsibk_pend *pending_req,
	enum tcm_tmreq_table act, int tag)
{
	int rc, err = FAILED;
	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
	struct se_cmd *se_cmd = &pending_req->se_cmd;
	struct scsiback_tmr *tmr;

	tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
	if (!tmr)
		goto out;

	init_waitqueue_head(&tmr->tmr_wait);

	transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
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		tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
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		&pending_req->sense_buffer[0]);

	rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
	if (rc < 0)
		goto out;

	se_cmd->se_tmr_req->ref_task_tag = tag;

	if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
		goto out;

	transport_generic_handle_tmr(se_cmd);
	wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));

	err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
		SUCCESS : FAILED;

out:
	if (tmr) {
		transport_generic_free_cmd(&pending_req->se_cmd, 1);
		kfree(tmr);
	}

	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);

	kmem_cache_free(scsiback_cachep, pending_req);
}

/*
  Perform virtual to physical translation
*/
static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
			struct ids_tuple *v)
{
	struct v2p_entry *entry;
	struct list_head *head = &(info->v2p_entry_lists);
	unsigned long flags;

	spin_lock_irqsave(&info->v2p_lock, flags);
	list_for_each_entry(entry, head, l) {
		if ((entry->v.chn == v->chn) &&
		    (entry->v.tgt == v->tgt) &&
		    (entry->v.lun == v->lun)) {
			kref_get(&entry->kref);
			goto out;
		}
	}
	entry = NULL;

out:
	spin_unlock_irqrestore(&info->v2p_lock, flags);
	return entry;
}

static int prepare_pending_reqs(struct vscsibk_info *info,
				struct vscsiif_request *ring_req,
				struct vscsibk_pend *pending_req)
{
	struct v2p_entry *v2p;
	struct ids_tuple vir;

	pending_req->rqid       = ring_req->rqid;
	pending_req->info       = info;

	vir.chn = ring_req->channel;
	vir.tgt = ring_req->id;
	vir.lun = ring_req->lun;

	v2p = scsiback_do_translation(info, &vir);
	if (!v2p) {
		pending_req->v2p = NULL;
679 680
		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
			vir.chn, vir.tgt, vir.lun);
681 682 683 684 685 686 687 688 689 690
		return -ENODEV;
	}
	pending_req->v2p = v2p;

	/* request range check from frontend */
	pending_req->sc_data_direction = ring_req->sc_data_direction;
	if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
		(pending_req->sc_data_direction != DMA_TO_DEVICE) &&
		(pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
		(pending_req->sc_data_direction != DMA_NONE)) {
691
		pr_debug("invalid parameter data_dir = %d\n",
692 693 694 695 696 697
			pending_req->sc_data_direction);
		return -EINVAL;
	}

	pending_req->cmd_len = ring_req->cmd_len;
	if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
698
		pr_debug("invalid parameter cmd_len = %d\n",
699 700 701 702 703 704 705 706 707 708 709
			pending_req->cmd_len);
		return -EINVAL;
	}
	memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);

	return 0;
}

static int scsiback_do_cmd_fn(struct vscsibk_info *info)
{
	struct vscsiif_back_ring *ring = &info->ring;
710
	struct vscsiif_request ring_req;
711 712 713 714 715 716 717 718 719 720 721
	struct vscsibk_pend *pending_req;
	RING_IDX rc, rp;
	int err, more_to_do;
	uint32_t result;

	rc = ring->req_cons;
	rp = ring->sring->req_prod;
	rmb();	/* guest system is accessing ring, too */

	if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
		rc = ring->rsp_prod_pvt;
722
		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
723 724 725 726 727 728 729 730 731 732 733 734
			   info->domid, rp, rc, rp - rc);
		info->ring_error = 1;
		return 0;
	}

	while ((rc != rp)) {
		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
			break;
		pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
		if (!pending_req)
			return 1;

735
		ring_req = *RING_GET_REQUEST(ring, rc);
736 737
		ring->req_cons = ++rc;

738
		err = prepare_pending_reqs(info, &ring_req, pending_req);
739 740 741 742 743 744 745 746 747 748 749 750 751 752 753
		if (err) {
			switch (err) {
			case -ENODEV:
				result = DID_NO_CONNECT;
				break;
			default:
				result = DRIVER_ERROR;
				break;
			}
			scsiback_do_resp_with_sense(NULL, result << 24, 0,
						    pending_req);
			kmem_cache_free(scsiback_cachep, pending_req);
			return 1;
		}

754
		switch (ring_req.act) {
755
		case VSCSIIF_ACT_SCSI_CDB:
756
			if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
757 758 759 760 761 762 763 764 765 766
				scsiback_fast_flush_area(pending_req);
				scsiback_do_resp_with_sense(NULL,
					DRIVER_ERROR << 24, 0, pending_req);
				kmem_cache_free(scsiback_cachep, pending_req);
			} else {
				scsiback_cmd_exec(pending_req);
			}
			break;
		case VSCSIIF_ACT_SCSI_ABORT:
			scsiback_device_action(pending_req, TMR_ABORT_TASK,
767
				ring_req.ref_rqid);
768 769 770 771 772
			break;
		case VSCSIIF_ACT_SCSI_RESET:
			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
			break;
		default:
773
			pr_err_ratelimited("invalid request\n");
774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810
			scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
						    0, pending_req);
			kmem_cache_free(scsiback_cachep, pending_req);
			break;
		}

		/* Yield point for this unbounded loop. */
		cond_resched();
	}

	RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
	return more_to_do;
}

static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
{
	struct vscsibk_info *info = dev_id;

	if (info->ring_error)
		return IRQ_HANDLED;

	while (scsiback_do_cmd_fn(info))
		cond_resched();

	return IRQ_HANDLED;
}

static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
			evtchn_port_t evtchn)
{
	void *area;
	struct vscsiif_sring *sring;
	int err;

	if (info->irq)
		return -1;

811
	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868
	if (err)
		return err;

	sring = (struct vscsiif_sring *)area;
	BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);

	err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
	if (err < 0)
		goto unmap_page;

	info->irq = err;

	err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
				   IRQF_ONESHOT, "vscsiif-backend", info);
	if (err)
		goto free_irq;

	return 0;

free_irq:
	unbind_from_irqhandler(info->irq, info);
	info->irq = 0;
unmap_page:
	xenbus_unmap_ring_vfree(info->dev, area);

	return err;
}

static int scsiback_map(struct vscsibk_info *info)
{
	struct xenbus_device *dev = info->dev;
	unsigned int ring_ref, evtchn;
	int err;

	err = xenbus_gather(XBT_NIL, dev->otherend,
			"ring-ref", "%u", &ring_ref,
			"event-channel", "%u", &evtchn, NULL);
	if (err) {
		xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
		return err;
	}

	return scsiback_init_sring(info, ring_ref, evtchn);
}

/*
  Add a new translation entry
*/
static int scsiback_add_translation_entry(struct vscsibk_info *info,
					  char *phy, struct ids_tuple *v)
{
	int err = 0;
	struct v2p_entry *entry;
	struct v2p_entry *new;
	struct list_head *head = &(info->v2p_entry_lists);
	unsigned long flags;
	char *lunp;
869 870
	unsigned int unpacked_lun;
	struct se_lun *se_lun;
871 872 873 874 875
	struct scsiback_tpg *tpg_entry, *tpg = NULL;
	char *error = "doesn't exist";

	lunp = strrchr(phy, ':');
	if (!lunp) {
876
		pr_err("illegal format of physical device %s\n", phy);
877 878 879 880
		return -EINVAL;
	}
	*lunp = 0;
	lunp++;
881
	if (kstrtouint(lunp, 10, &unpacked_lun) || unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
882
		pr_err("lun number not valid: %s\n", lunp);
883 884 885 886 887 888 889
		return -EINVAL;
	}

	mutex_lock(&scsiback_mutex);
	list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
		if (!strcmp(phy, tpg_entry->tport->tport_name) ||
		    !strcmp(phy, tpg_entry->param_alias)) {
890 891 892 893 894 895 896 897 898
			mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
			hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
				if (se_lun->unpacked_lun == unpacked_lun) {
					if (!tpg_entry->tpg_nexus)
						error = "nexus undefined";
					else
						tpg = tpg_entry;
					break;
				}
899
			}
900
			mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
901 902 903 904 905 906 907 908 909 910 911
			break;
		}
	}
	if (tpg) {
		mutex_lock(&tpg->tv_tpg_mutex);
		tpg->tv_tpg_fe_count++;
		mutex_unlock(&tpg->tv_tpg_mutex);
	}
	mutex_unlock(&scsiback_mutex);

	if (!tpg) {
912
		pr_err("%s:%d %s\n", phy, unpacked_lun, error);
913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928
		return -ENODEV;
	}

	new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
	if (new == NULL) {
		err = -ENOMEM;
		goto out_free;
	}

	spin_lock_irqsave(&info->v2p_lock, flags);

	/* Check double assignment to identical virtual ID */
	list_for_each_entry(entry, head, l) {
		if ((entry->v.chn == v->chn) &&
		    (entry->v.tgt == v->tgt) &&
		    (entry->v.lun == v->lun)) {
929
			pr_warn("Virtual ID is already used. Assignment was not performed.\n");
930 931 932 933 934 935 936 937 938 939
			err = -EEXIST;
			goto out;
		}

	}

	/* Create a new translation entry and add to the list */
	kref_init(&new->kref);
	new->v = *v;
	new->tpg = tpg;
940
	new->lun = unpacked_lun;
941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
	list_add_tail(&new->l, head);

out:
	spin_unlock_irqrestore(&info->v2p_lock, flags);

out_free:
	mutex_lock(&tpg->tv_tpg_mutex);
	tpg->tv_tpg_fe_count--;
	mutex_unlock(&tpg->tv_tpg_mutex);

	if (err)
		kfree(new);

	return err;
}

static void __scsiback_del_translation_entry(struct v2p_entry *entry)
{
	list_del(&entry->l);
	kref_put(&entry->kref, scsiback_free_translation_entry);
}

/*
  Delete the translation entry specfied
*/
static int scsiback_del_translation_entry(struct vscsibk_info *info,
					  struct ids_tuple *v)
{
	struct v2p_entry *entry;
	struct list_head *head = &(info->v2p_entry_lists);
	unsigned long flags;

	spin_lock_irqsave(&info->v2p_lock, flags);
	/* Find out the translation entry specified */
	list_for_each_entry(entry, head, l) {
		if ((entry->v.chn == v->chn) &&
		    (entry->v.tgt == v->tgt) &&
		    (entry->v.lun == v->lun)) {
			goto found;
		}
	}

	spin_unlock_irqrestore(&info->v2p_lock, flags);
	return 1;

found:
	/* Delete the translation entry specfied */
	__scsiback_del_translation_entry(entry);

	spin_unlock_irqrestore(&info->v2p_lock, flags);
	return 0;
}

static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
995
				char *phy, struct ids_tuple *vir, int try)
996 997 998 999
{
	if (!scsiback_add_translation_entry(info, phy, vir)) {
		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
				  "%d", XenbusStateInitialised)) {
1000
			pr_err("xenbus_printf error %s\n", state);
1001 1002
			scsiback_del_translation_entry(info, vir);
		}
1003
	} else if (!try) {
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014
		xenbus_printf(XBT_NIL, info->dev->nodename, state,
			      "%d", XenbusStateClosed);
	}
}

static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
				struct ids_tuple *vir)
{
	if (!scsiback_del_translation_entry(info, vir)) {
		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
				  "%d", XenbusStateClosed))
1015
			pr_err("xenbus_printf error %s\n", state);
1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
	}
}

#define VSCSIBACK_OP_ADD_OR_DEL_LUN	1
#define VSCSIBACK_OP_UPDATEDEV_STATE	2

static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
				     char *ent)
{
	int err;
	struct ids_tuple vir;
	char *val;
	int device_state;
	char phy[VSCSI_NAMELEN];
	char str[64];
	char state[64];
	struct xenbus_device *dev = info->dev;

	/* read status */
	snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
	err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
	if (XENBUS_EXIST_ERR(err))
		return;

	/* physical SCSI device */
	snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
	val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
	if (IS_ERR(val)) {
		xenbus_printf(XBT_NIL, dev->nodename, state,
			      "%d", XenbusStateClosed);
		return;
	}
	strlcpy(phy, val, VSCSI_NAMELEN);
	kfree(val);

	/* virtual SCSI device */
	snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
	err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
			   &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
	if (XENBUS_EXIST_ERR(err)) {
		xenbus_printf(XBT_NIL, dev->nodename, state,
			      "%d", XenbusStateClosed);
		return;
	}

	switch (op) {
	case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1063 1064 1065 1066 1067 1068 1069 1070
		switch (device_state) {
		case XenbusStateInitialising:
			scsiback_do_add_lun(info, state, phy, &vir, 0);
			break;
		case XenbusStateConnected:
			scsiback_do_add_lun(info, state, phy, &vir, 1);
			break;
		case XenbusStateClosing:
1071
			scsiback_do_del_lun(info, state, &vir);
1072 1073 1074 1075
			break;
		default:
			break;
		}
1076 1077 1078 1079 1080 1081 1082
		break;

	case VSCSIBACK_OP_UPDATEDEV_STATE:
		if (device_state == XenbusStateInitialised) {
			/* modify vscsi-devs/dev-x/state */
			if (xenbus_printf(XBT_NIL, dev->nodename, state,
					  "%d", XenbusStateConnected)) {
1083
				pr_err("xenbus_printf error %s\n", str);
1084 1085 1086 1087 1088 1089
				scsiback_del_translation_entry(info, &vir);
				xenbus_printf(XBT_NIL, dev->nodename, state,
					      "%d", XenbusStateClosed);
			}
		}
		break;
1090
	/* When it is necessary, processing is added here. */
1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206
	default:
		break;
	}
}

static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
{
	int i;
	char **dir;
	unsigned int ndir = 0;

	dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
			       &ndir);
	if (IS_ERR(dir))
		return;

	for (i = 0; i < ndir; i++)
		scsiback_do_1lun_hotplug(info, op, dir[i]);

	kfree(dir);
}

static void scsiback_frontend_changed(struct xenbus_device *dev,
					enum xenbus_state frontend_state)
{
	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);

	switch (frontend_state) {
	case XenbusStateInitialising:
		break;

	case XenbusStateInitialised:
		if (scsiback_map(info))
			break;

		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateConnected:
		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);

		if (dev->state == XenbusStateConnected)
			break;

		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateClosing:
		if (info->irq)
			scsiback_disconnect(info);

		xenbus_switch_state(dev, XenbusStateClosing);
		break;

	case XenbusStateClosed:
		xenbus_switch_state(dev, XenbusStateClosed);
		if (xenbus_dev_is_online(dev))
			break;
		/* fall through if not online */
	case XenbusStateUnknown:
		device_unregister(&dev->dev);
		break;

	case XenbusStateReconfiguring:
		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
		xenbus_switch_state(dev, XenbusStateReconfigured);

		break;

	default:
		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
					frontend_state);
		break;
	}
}

/*
  Release the translation entry specfied
*/
static void scsiback_release_translation_entry(struct vscsibk_info *info)
{
	struct v2p_entry *entry, *tmp;
	struct list_head *head = &(info->v2p_entry_lists);
	unsigned long flags;

	spin_lock_irqsave(&info->v2p_lock, flags);

	list_for_each_entry_safe(entry, tmp, head, l)
		__scsiback_del_translation_entry(entry);

	spin_unlock_irqrestore(&info->v2p_lock, flags);
}

static int scsiback_remove(struct xenbus_device *dev)
{
	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);

	if (info->irq)
		scsiback_disconnect(info);

	scsiback_release_translation_entry(info);

	dev_set_drvdata(&dev->dev, NULL);

	return 0;
}

static int scsiback_probe(struct xenbus_device *dev,
			   const struct xenbus_device_id *id)
{
	int err;

	struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
					    GFP_KERNEL);

1207
	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237

	if (!info) {
		xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
		return -ENOMEM;
	}
	info->dev = dev;
	dev_set_drvdata(&dev->dev, info);

	info->domid = dev->otherend_id;
	spin_lock_init(&info->ring_lock);
	info->ring_error = 0;
	atomic_set(&info->nr_unreplied_reqs, 0);
	init_waitqueue_head(&info->waiting_to_free);
	info->dev = dev;
	info->irq = 0;
	INIT_LIST_HEAD(&info->v2p_entry_lists);
	spin_lock_init(&info->v2p_lock);

	err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
			    SG_ALL);
	if (err)
		xenbus_dev_error(dev, err, "writing feature-sg-grant");

	err = xenbus_switch_state(dev, XenbusStateInitWait);
	if (err)
		goto fail;

	return 0;

fail:
1238
	pr_warn("%s failed\n", __func__);
1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
	scsiback_remove(dev);

	return err;
}

static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
{
	switch (tport->tport_proto_id) {
	case SCSI_PROTOCOL_SAS:
		return "SAS";
	case SCSI_PROTOCOL_FCP:
		return "FCP";
	case SCSI_PROTOCOL_ISCSI:
		return "iSCSI";
	default:
		break;
	}

	return "Unknown";
}

static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);
	struct scsiback_tport *tport = tpg->tport;

	return &tport->tport_name[0];
}

static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);
	return tpg->tport_tpgt;
}

static struct se_wwn *
scsiback_make_tport(struct target_fabric_configfs *tf,
		     struct config_group *group,
		     const char *name)
{
	struct scsiback_tport *tport;
	char *ptr;
	u64 wwpn = 0;
	int off = 0;

	tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
	if (!tport)
		return ERR_PTR(-ENOMEM);

	tport->tport_wwpn = wwpn;
	/*
	 * Determine the emulated Protocol Identifier and Target Port Name
	 * based on the incoming configfs directory name.
	 */
	ptr = strstr(name, "naa.");
	if (ptr) {
		tport->tport_proto_id = SCSI_PROTOCOL_SAS;
		goto check_len;
	}
	ptr = strstr(name, "fc.");
	if (ptr) {
		tport->tport_proto_id = SCSI_PROTOCOL_FCP;
		off = 3; /* Skip over "fc." */
		goto check_len;
	}
	ptr = strstr(name, "iqn.");
	if (ptr) {
		tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
		goto check_len;
	}

	pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
	kfree(tport);
	return ERR_PTR(-EINVAL);

check_len:
	if (strlen(name) >= VSCSI_NAMELEN) {
		pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
			scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
		kfree(tport);
		return ERR_PTR(-EINVAL);
	}
	snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);

1325
	pr_debug("Allocated emulated Target %s Address: %s\n",
1326 1327 1328 1329 1330 1331 1332 1333 1334 1335
		 scsiback_dump_proto_id(tport), name);

	return &tport->tport_wwn;
}

static void scsiback_drop_tport(struct se_wwn *wwn)
{
	struct scsiback_tport *tport = container_of(wwn,
				struct scsiback_tport, tport_wwn);

1336
	pr_debug("Deallocating emulated Target %s Address: %s\n",
1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349
		 scsiback_dump_proto_id(tport), tport->tport_name);

	kfree(tport);
}

static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
{
	return 1;
}

static int scsiback_check_stop_free(struct se_cmd *se_cmd)
{
	/*
1350 1351
	 * Do not release struct se_cmd's containing a valid TMR pointer.
	 * These will be released directly in scsiback_device_action()
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508
	 * with transport_generic_free_cmd().
	 */
	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
		return 0;

	transport_generic_free_cmd(se_cmd, 0);
	return 1;
}

static void scsiback_release_cmd(struct se_cmd *se_cmd)
{
	struct vscsibk_pend *pending_req = container_of(se_cmd,
				struct vscsibk_pend, se_cmd);

	kmem_cache_free(scsiback_cachep, pending_req);
}

static int scsiback_shutdown_session(struct se_session *se_sess)
{
	return 0;
}

static void scsiback_close_session(struct se_session *se_sess)
{
}

static u32 scsiback_sess_get_index(struct se_session *se_sess)
{
	return 0;
}

static int scsiback_write_pending(struct se_cmd *se_cmd)
{
	/* Go ahead and process the write immediately */
	target_execute_cmd(se_cmd);

	return 0;
}

static int scsiback_write_pending_status(struct se_cmd *se_cmd)
{
	return 0;
}

static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
{
}

static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
{
	return 0;
}

static int scsiback_queue_data_in(struct se_cmd *se_cmd)
{
	struct vscsibk_pend *pending_req = container_of(se_cmd,
				struct vscsibk_pend, se_cmd);

	pending_req->result = SAM_STAT_GOOD;
	scsiback_cmd_done(pending_req);
	return 0;
}

static int scsiback_queue_status(struct se_cmd *se_cmd)
{
	struct vscsibk_pend *pending_req = container_of(se_cmd,
				struct vscsibk_pend, se_cmd);

	if (se_cmd->sense_buffer &&
	    ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
	     (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
		pending_req->result = (DRIVER_SENSE << 24) |
				      SAM_STAT_CHECK_CONDITION;
	else
		pending_req->result = se_cmd->scsi_status;

	scsiback_cmd_done(pending_req);
	return 0;
}

static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
{
	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
	struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;

	atomic_set(&tmr->tmr_complete, 1);
	wake_up(&tmr->tmr_wait);
}

static void scsiback_aborted_task(struct se_cmd *se_cmd)
{
}

static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
					     char *page)
{
	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
						se_tpg);
	ssize_t rb;

	mutex_lock(&tpg->tv_tpg_mutex);
	rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
	mutex_unlock(&tpg->tv_tpg_mutex);

	return rb;
}

static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
					      const char *page, size_t count)
{
	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
						se_tpg);
	int len;

	if (strlen(page) >= VSCSI_NAMELEN) {
		pr_err("param alias: %s, exceeds max: %d\n", page,
			VSCSI_NAMELEN);
		return -EINVAL;
	}

	mutex_lock(&tpg->tv_tpg_mutex);
	len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
	if (tpg->param_alias[len - 1] == '\n')
		tpg->param_alias[len - 1] = '\0';
	mutex_unlock(&tpg->tv_tpg_mutex);

	return count;
}

TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);

static struct configfs_attribute *scsiback_param_attrs[] = {
	&scsiback_tpg_param_alias.attr,
	NULL,
};

static int scsiback_make_nexus(struct scsiback_tpg *tpg,
				const char *name)
{
	struct se_portal_group *se_tpg;
	struct se_session *se_sess;
	struct scsiback_nexus *tv_nexus;

	mutex_lock(&tpg->tv_tpg_mutex);
	if (tpg->tpg_nexus) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		pr_debug("tpg->tpg_nexus already exists\n");
		return -EEXIST;
	}
	se_tpg = &tpg->se_tpg;

	tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
	if (!tv_nexus) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		return -ENOMEM;
	}
	/*
1509
	 * Initialize the struct se_session pointer
1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530
	 */
	tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
	if (IS_ERR(tv_nexus->tvn_se_sess)) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		kfree(tv_nexus);
		return -ENOMEM;
	}
	se_sess = tv_nexus->tvn_se_sess;
	/*
	 * Since we are running in 'demo mode' this call with generate a
	 * struct se_node_acl for the scsiback struct se_portal_group with
	 * the SCSI Initiator port name of the passed configfs group 'name'.
	 */
	tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
				se_tpg, (unsigned char *)name);
	if (!tv_nexus->tvn_se_sess->se_node_acl) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
			 name);
		goto out;
	}
1531 1532
	/* Now register the TCM pvscsi virtual I_T Nexus as active. */
	transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
			tv_nexus->tvn_se_sess, tv_nexus);
	tpg->tpg_nexus = tv_nexus;

	mutex_unlock(&tpg->tv_tpg_mutex);
	return 0;

out:
	transport_free_session(se_sess);
	kfree(tv_nexus);
	return -ENOMEM;
}

static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
{
	struct se_session *se_sess;
	struct scsiback_nexus *tv_nexus;

	mutex_lock(&tpg->tv_tpg_mutex);
	tv_nexus = tpg->tpg_nexus;
	if (!tv_nexus) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		return -ENODEV;
	}

	se_sess = tv_nexus->tvn_se_sess;
	if (!se_sess) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		return -ENODEV;
	}

	if (tpg->tv_tpg_port_count != 0) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
			tpg->tv_tpg_port_count);
		return -EBUSY;
	}

	if (tpg->tv_tpg_fe_count != 0) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
			tpg->tv_tpg_fe_count);
		return -EBUSY;
	}

1577
	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622
		scsiback_dump_proto_id(tpg->tport),
		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);

	/*
	 * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
	 */
	transport_deregister_session(tv_nexus->tvn_se_sess);
	tpg->tpg_nexus = NULL;
	mutex_unlock(&tpg->tv_tpg_mutex);

	kfree(tv_nexus);
	return 0;
}

static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
					char *page)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);
	struct scsiback_nexus *tv_nexus;
	ssize_t ret;

	mutex_lock(&tpg->tv_tpg_mutex);
	tv_nexus = tpg->tpg_nexus;
	if (!tv_nexus) {
		mutex_unlock(&tpg->tv_tpg_mutex);
		return -ENODEV;
	}
	ret = snprintf(page, PAGE_SIZE, "%s\n",
			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
	mutex_unlock(&tpg->tv_tpg_mutex);

	return ret;
}

static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
					 const char *page,
					 size_t count)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);
	struct scsiback_tport *tport_wwn = tpg->tport;
	unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
	int ret;
	/*
1623
	 * Shutdown the active I_T nexus if 'NULL' is passed.
1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748
	 */
	if (!strncmp(page, "NULL", 4)) {
		ret = scsiback_drop_nexus(tpg);
		return (!ret) ? count : ret;
	}
	/*
	 * Otherwise make sure the passed virtual Initiator port WWN matches
	 * the fabric protocol_id set in scsiback_make_tport(), and call
	 * scsiback_make_nexus().
	 */
	if (strlen(page) >= VSCSI_NAMELEN) {
		pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
			page, VSCSI_NAMELEN);
		return -EINVAL;
	}
	snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);

	ptr = strstr(i_port, "naa.");
	if (ptr) {
		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
			pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
				i_port, scsiback_dump_proto_id(tport_wwn));
			return -EINVAL;
		}
		port_ptr = &i_port[0];
		goto check_newline;
	}
	ptr = strstr(i_port, "fc.");
	if (ptr) {
		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
			pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
				i_port, scsiback_dump_proto_id(tport_wwn));
			return -EINVAL;
		}
		port_ptr = &i_port[3]; /* Skip over "fc." */
		goto check_newline;
	}
	ptr = strstr(i_port, "iqn.");
	if (ptr) {
		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
			pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
				i_port, scsiback_dump_proto_id(tport_wwn));
			return -EINVAL;
		}
		port_ptr = &i_port[0];
		goto check_newline;
	}
	pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
		i_port);
	return -EINVAL;
	/*
	 * Clear any trailing newline for the NAA WWN
	 */
check_newline:
	if (i_port[strlen(i_port) - 1] == '\n')
		i_port[strlen(i_port) - 1] = '\0';

	ret = scsiback_make_nexus(tpg, port_ptr);
	if (ret < 0)
		return ret;

	return count;
}

TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);

static struct configfs_attribute *scsiback_tpg_attrs[] = {
	&scsiback_tpg_nexus.attr,
	NULL,
};

static ssize_t
scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
				char *page)
{
	return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
		UTS_RELEASE"\n",
		VSCSI_VERSION, utsname()->sysname, utsname()->machine);
}

TF_WWN_ATTR_RO(scsiback, version);

static struct configfs_attribute *scsiback_wwn_attrs[] = {
	&scsiback_wwn_version.attr,
	NULL,
};

static char *scsiback_get_fabric_name(void)
{
	return "xen-pvscsi";
}

static int scsiback_port_link(struct se_portal_group *se_tpg,
			       struct se_lun *lun)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);

	mutex_lock(&tpg->tv_tpg_mutex);
	tpg->tv_tpg_port_count++;
	mutex_unlock(&tpg->tv_tpg_mutex);

	return 0;
}

static void scsiback_port_unlink(struct se_portal_group *se_tpg,
				  struct se_lun *lun)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);

	mutex_lock(&tpg->tv_tpg_mutex);
	tpg->tv_tpg_port_count--;
	mutex_unlock(&tpg->tv_tpg_mutex);
}

static struct se_portal_group *
scsiback_make_tpg(struct se_wwn *wwn,
		   struct config_group *group,
		   const char *name)
{
	struct scsiback_tport *tport = container_of(wwn,
			struct scsiback_tport, tport_wwn);

	struct scsiback_tpg *tpg;
1749
	u16 tpgt;
1750 1751 1752 1753
	int ret;

	if (strstr(name, "tpgt_") != name)
		return ERR_PTR(-EINVAL);
1754 1755 1756
	ret = kstrtou16(name + 5, 10, &tpgt);
	if (ret)
		return ERR_PTR(ret);
1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767

	tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
	if (!tpg)
		return ERR_PTR(-ENOMEM);

	mutex_init(&tpg->tv_tpg_mutex);
	INIT_LIST_HEAD(&tpg->tv_tpg_list);
	INIT_LIST_HEAD(&tpg->info_list);
	tpg->tport = tport;
	tpg->tport_tpgt = tpgt;

1768 1769
	ret = core_tpg_register(&scsiback_ops, wwn, &tpg->se_tpg,
				tport->tport_proto_id);
1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
	if (ret < 0) {
		kfree(tpg);
		return NULL;
	}
	mutex_lock(&scsiback_mutex);
	list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
	mutex_unlock(&scsiback_mutex);

	return &tpg->se_tpg;
}

static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);

	mutex_lock(&scsiback_mutex);
	list_del(&tpg->tv_tpg_list);
	mutex_unlock(&scsiback_mutex);
	/*
	 * Release the virtual I_T Nexus for this xen-pvscsi TPG
	 */
	scsiback_drop_nexus(tpg);
	/*
1794
	 * Deregister the se_tpg from TCM.
1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809
	 */
	core_tpg_deregister(se_tpg);
	kfree(tpg);
}

static int scsiback_check_true(struct se_portal_group *se_tpg)
{
	return 1;
}

static int scsiback_check_false(struct se_portal_group *se_tpg)
{
	return 0;
}

1810 1811 1812
static const struct target_core_fabric_ops scsiback_ops = {
	.module				= THIS_MODULE,
	.name				= "xen-pvscsi",
1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844
	.get_fabric_name		= scsiback_get_fabric_name,
	.tpg_get_wwn			= scsiback_get_fabric_wwn,
	.tpg_get_tag			= scsiback_get_tag,
	.tpg_check_demo_mode		= scsiback_check_true,
	.tpg_check_demo_mode_cache	= scsiback_check_true,
	.tpg_check_demo_mode_write_protect = scsiback_check_false,
	.tpg_check_prod_mode_write_protect = scsiback_check_false,
	.tpg_get_inst_index		= scsiback_tpg_get_inst_index,
	.check_stop_free		= scsiback_check_stop_free,
	.release_cmd			= scsiback_release_cmd,
	.shutdown_session		= scsiback_shutdown_session,
	.close_session			= scsiback_close_session,
	.sess_get_index			= scsiback_sess_get_index,
	.sess_get_initiator_sid		= NULL,
	.write_pending			= scsiback_write_pending,
	.write_pending_status		= scsiback_write_pending_status,
	.set_default_node_attributes	= scsiback_set_default_node_attrs,
	.get_cmd_state			= scsiback_get_cmd_state,
	.queue_data_in			= scsiback_queue_data_in,
	.queue_status			= scsiback_queue_status,
	.queue_tm_rsp			= scsiback_queue_tm_rsp,
	.aborted_task			= scsiback_aborted_task,
	/*
	 * Setup callers for generic logic in target_core_fabric_configfs.c
	 */
	.fabric_make_wwn		= scsiback_make_tport,
	.fabric_drop_wwn		= scsiback_drop_tport,
	.fabric_make_tpg		= scsiback_make_tpg,
	.fabric_drop_tpg		= scsiback_drop_tpg,
	.fabric_post_link		= scsiback_port_link,
	.fabric_pre_unlink		= scsiback_port_unlink,

1845 1846 1847
	.tfc_wwn_attrs			= scsiback_wwn_attrs,
	.tfc_tpg_base_attrs		= scsiback_tpg_attrs,
	.tfc_tpg_param_attrs		= scsiback_param_attrs,
1848 1849 1850 1851 1852 1853 1854
};

static const struct xenbus_device_id scsiback_ids[] = {
	{ "vscsi" },
	{ "" }
};

1855 1856
static struct xenbus_driver scsiback_driver = {
	.ids			= scsiback_ids,
1857 1858 1859
	.probe			= scsiback_probe,
	.remove			= scsiback_remove,
	.otherend_changed	= scsiback_frontend_changed
1860
};
1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878

static void scsiback_init_pend(void *p)
{
	struct vscsibk_pend *pend = p;
	int i;

	memset(pend, 0, sizeof(*pend));
	for (i = 0; i < VSCSI_MAX_GRANTS; i++)
		pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
}

static int __init scsiback_init(void)
{
	int ret;

	if (!xen_domain())
		return -ENODEV;

1879 1880 1881
	pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);

1882 1883 1884 1885 1886 1887 1888 1889 1890
	scsiback_cachep = kmem_cache_create("vscsiif_cache",
		sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
	if (!scsiback_cachep)
		return -ENOMEM;

	ret = xenbus_register_backend(&scsiback_driver);
	if (ret)
		goto out_cache_destroy;

1891
	ret = target_register_template(&scsiback_ops);
1892 1893 1894 1895 1896 1897 1898 1899 1900
	if (ret)
		goto out_unregister_xenbus;

	return 0;

out_unregister_xenbus:
	xenbus_unregister_driver(&scsiback_driver);
out_cache_destroy:
	kmem_cache_destroy(scsiback_cachep);
1901
	pr_err("%s: error %d\n", __func__, ret);
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911
	return ret;
}

static void __exit scsiback_exit(void)
{
	struct page *page;

	while (free_pages_num) {
		if (get_free_page(&page))
			BUG();
1912
		gnttab_free_pages(1, &page);
1913
	}
1914
	target_unregister_template(&scsiback_ops);
1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925
	xenbus_unregister_driver(&scsiback_driver);
	kmem_cache_destroy(scsiback_cachep);
}

module_init(scsiback_init);
module_exit(scsiback_exit);

MODULE_DESCRIPTION("Xen SCSI backend driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("xen-backend:vscsi");
MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");