xen-scsiback.c 47.3 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_host.h> /* SG_ALL */
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#include <target/target_core_base.h>
#include <target/target_core_fabric.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;

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	struct completion tmr_done;
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};

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#define VSCSI_DEFAULT_SESSION_TAGS	128

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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 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);

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);
}

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static void scsiback_send_response(struct vscsibk_info *info,
			char *sense_buffer, int32_t result, uint32_t resid,
			uint16_t rqid)
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{
	struct vscsiif_response *ring_res;
	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;
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	ring_res->rqid   = rqid;
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	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);
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}

static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
			uint32_t resid, struct vscsibk_pend *pending_req)
{
	scsiback_send_response(pending_req->info, sense_buffer, result,
			       resid, pending_req->rqid);
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	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);
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	/*
	 * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
	 * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
	 * final se_cmd->cmd_kref put.
	 */
	target_put_sess_cmd(&pending_req->se_cmd);
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}

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;

	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,
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			pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
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			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)
{
	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
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	struct scsiback_nexus *nexus = tpg->tpg_nexus;
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	struct se_cmd *se_cmd = &pending_req->se_cmd;
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	u64 unpacked_lun = pending_req->v2p->lun;
	int rc, err = FAILED;
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	init_completion(&pending_req->tmr_done);
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	rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
			       &pending_req->sense_buffer[0],
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			       unpacked_lun, NULL, act, GFP_KERNEL,
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			       tag, TARGET_SCF_ACK_KREF);
	if (rc)
		goto err;
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	wait_for_completion(&pending_req->tmr_done);
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	err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
		SUCCESS : FAILED;

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	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
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	transport_generic_free_cmd(&pending_req->se_cmd, 0);
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	return;
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620
err:
621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649
	scsiback_do_resp_with_sense(NULL, err, 0, 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;
}

650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677
static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
				struct v2p_entry *v2p)
{
	struct scsiback_tpg *tpg = v2p->tpg;
	struct scsiback_nexus *nexus = tpg->tpg_nexus;
	struct se_session *se_sess = nexus->tvn_se_sess;
	struct vscsibk_pend *req;
	int tag, i;

	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
	if (tag < 0) {
		pr_err("Unable to obtain tag for vscsiif_request\n");
		return ERR_PTR(-ENOMEM);
	}

	req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
	memset(req, 0, sizeof(*req));
	req->se_cmd.map_tag = tag;

	for (i = 0; i < VSCSI_MAX_GRANTS; i++)
		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;

	return req;
}

static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
				struct vscsiif_back_ring *ring,
				struct vscsiif_request *ring_req)
678
{
679
	struct vscsibk_pend *pending_req;
680 681 682
	struct v2p_entry *v2p;
	struct ids_tuple vir;

683 684 685 686 687 688 689 690 691 692 693 694 695 696
	/* request range check from frontend */
	if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
		(ring_req->sc_data_direction != DMA_TO_DEVICE) &&
		(ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
		(ring_req->sc_data_direction != DMA_NONE)) {
		pr_debug("invalid parameter data_dir = %d\n",
			ring_req->sc_data_direction);
		return ERR_PTR(-EINVAL);
	}
	if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
		pr_debug("invalid parameter cmd_len = %d\n",
			ring_req->cmd_len);
		return ERR_PTR(-EINVAL);
	}
697 698 699 700 701 702 703

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

	v2p = scsiback_do_translation(info, &vir);
	if (!v2p) {
704
		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
705 706
			 vir.chn, vir.tgt, vir.lun);
		return ERR_PTR(-ENODEV);
707 708
	}

709 710 711 712
	pending_req = scsiback_get_pend_req(ring, v2p);
	if (IS_ERR(pending_req)) {
		kref_put(&v2p->kref, scsiback_free_translation_entry);
		return ERR_PTR(-ENOMEM);
713
	}
714 715 716 717
	pending_req->rqid = ring_req->rqid;
	pending_req->info = info;
	pending_req->v2p = v2p;
	pending_req->sc_data_direction = ring_req->sc_data_direction;
718 719 720
	pending_req->cmd_len = ring_req->cmd_len;
	memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);

721
	return pending_req;
722 723 724 725 726
}

static int scsiback_do_cmd_fn(struct vscsibk_info *info)
{
	struct vscsiif_back_ring *ring = &info->ring;
727
	struct vscsiif_request ring_req;
728 729
	struct vscsibk_pend *pending_req;
	RING_IDX rc, rp;
730
	int more_to_do;
731 732 733 734 735 736 737 738
	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;
739
		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
740 741 742 743 744 745 746 747 748
			   info->domid, rp, rc, rp - rc);
		info->ring_error = 1;
		return 0;
	}

	while ((rc != rp)) {
		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
			break;

749
		RING_COPY_REQUEST(ring, rc, &ring_req);
750 751
		ring->req_cons = ++rc;

752 753 754
		pending_req = prepare_pending_reqs(info, ring, &ring_req);
		if (IS_ERR(pending_req)) {
			switch (PTR_ERR(pending_req)) {
755 756 757 758 759 760 761
			case -ENODEV:
				result = DID_NO_CONNECT;
				break;
			default:
				result = DRIVER_ERROR;
				break;
			}
762 763
			scsiback_send_response(info, NULL, result << 24, 0,
					       ring_req.rqid);
764 765 766
			return 1;
		}

767
		switch (ring_req.act) {
768
		case VSCSIIF_ACT_SCSI_CDB:
769
			if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
770 771
				scsiback_fast_flush_area(pending_req);
				scsiback_do_resp_with_sense(NULL,
772 773
						DRIVER_ERROR << 24, 0, pending_req);
				transport_generic_free_cmd(&pending_req->se_cmd, 0);
774 775 776 777 778 779
			} else {
				scsiback_cmd_exec(pending_req);
			}
			break;
		case VSCSIIF_ACT_SCSI_ABORT:
			scsiback_device_action(pending_req, TMR_ABORT_TASK,
780
				ring_req.ref_rqid);
781 782 783 784 785
			break;
		case VSCSIIF_ACT_SCSI_RESET:
			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
			break;
		default:
786
			pr_err_ratelimited("invalid request\n");
787 788 789
			scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
						    pending_req);
			transport_generic_free_cmd(&pending_req->se_cmd, 0);
790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823
			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;

824
	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869
	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);
}

870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
/*
  Check for a translation entry being present
*/
static struct v2p_entry *scsiback_chk_translation_entry(
	struct vscsibk_info *info, struct ids_tuple *v)
{
	struct list_head *head = &(info->v2p_entry_lists);
	struct v2p_entry *entry;

	list_for_each_entry(entry, head, l)
		if ((entry->v.chn == v->chn) &&
		    (entry->v.tgt == v->tgt) &&
		    (entry->v.lun == v->lun))
			return entry;

	return NULL;
}

888 889 890 891 892 893 894 895 896 897
/*
  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 *new;
	unsigned long flags;
	char *lunp;
898
	unsigned long long unpacked_lun;
899
	struct se_lun *se_lun;
900 901 902 903 904
	struct scsiback_tpg *tpg_entry, *tpg = NULL;
	char *error = "doesn't exist";

	lunp = strrchr(phy, ':');
	if (!lunp) {
905
		pr_err("illegal format of physical device %s\n", phy);
906 907 908 909
		return -EINVAL;
	}
	*lunp = 0;
	lunp++;
910 911
	err = kstrtoull(lunp, 10, &unpacked_lun);
	if (err < 0) {
912
		pr_err("lun number not valid: %s\n", lunp);
913
		return err;
914 915 916 917 918 919
	}

	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)) {
920 921 922 923 924 925 926 927 928
			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;
				}
929
			}
930
			mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
931 932 933 934 935 936 937 938 939 940 941
			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) {
942
		pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
943 944 945 946 947 948 949 950 951 952 953 954
		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 */
955 956 957 958
	if (scsiback_chk_translation_entry(info, v)) {
		pr_warn("Virtual ID is already used. Assignment was not performed.\n");
		err = -EEXIST;
		goto out;
959 960 961 962 963 964
	}

	/* Create a new translation entry and add to the list */
	kref_init(&new->kref);
	new->v = *v;
	new->tpg = tpg;
965
	new->lun = unpacked_lun;
966
	list_add_tail(&new->l, &info->v2p_entry_lists);
967 968 969 970 971

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

out_free:
972 973 974 975
	if (err) {
		mutex_lock(&tpg->tv_tpg_mutex);
		tpg->tv_tpg_fe_count--;
		mutex_unlock(&tpg->tv_tpg_mutex);
976
		kfree(new);
977
	}
978 979 980 981 982 983 984 985 986 987 988

	return err;
}

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

/*
989
  Delete the translation entry specified
990 991 992 993 994 995
*/
static int scsiback_del_translation_entry(struct vscsibk_info *info,
					  struct ids_tuple *v)
{
	struct v2p_entry *entry;
	unsigned long flags;
996
	int ret = 0;
997 998 999

	spin_lock_irqsave(&info->v2p_lock, flags);
	/* Find out the translation entry specified */
1000 1001 1002 1003 1004
	entry = scsiback_chk_translation_entry(info, v);
	if (entry)
		__scsiback_del_translation_entry(entry);
	else
		ret = -ENOENT;
1005 1006

	spin_unlock_irqrestore(&info->v2p_lock, flags);
1007
	return ret;
1008 1009 1010
}

static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1011
				char *phy, struct ids_tuple *vir, int try)
1012
{
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	struct v2p_entry *entry;
	unsigned long flags;

	if (try) {
		spin_lock_irqsave(&info->v2p_lock, flags);
		entry = scsiback_chk_translation_entry(info, vir);
		spin_unlock_irqrestore(&info->v2p_lock, flags);
		if (entry)
			return;
	}
1023 1024 1025
	if (!scsiback_add_translation_entry(info, phy, vir)) {
		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
				  "%d", XenbusStateInitialised)) {
1026
			pr_err("xenbus_printf error %s\n", state);
1027 1028
			scsiback_del_translation_entry(info, vir);
		}
1029
	} else if (!try) {
1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
		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))
1041
			pr_err("xenbus_printf error %s\n", state);
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088
	}
}

#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:
1089 1090 1091 1092 1093 1094 1095 1096
		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:
1097
			scsiback_do_del_lun(info, state, &vir);
1098 1099 1100 1101
			break;
		default:
			break;
		}
1102 1103 1104 1105 1106 1107 1108
		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)) {
1109
				pr_err("xenbus_printf error %s\n", str);
1110 1111 1112 1113 1114 1115
				scsiback_del_translation_entry(info, &vir);
				xenbus_printf(XBT_NIL, dev->nodename, state,
					      "%d", XenbusStateClosed);
			}
		}
		break;
1116
	/* When it is necessary, processing is added here. */
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 1207 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
	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);

1233
	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1234 1235 1236 1237 1238 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

	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:
1264
	pr_warn("%s failed\n", __func__);
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 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350
	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]);

1351
	pr_debug("Allocated emulated Target %s Address: %s\n",
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361
		 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);

1362
	pr_debug("Deallocating emulated Target %s Address: %s\n",
1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374
		 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)
{
1375
	return transport_generic_free_cmd(se_cmd, 0);
1376 1377 1378 1379
}

static void scsiback_release_cmd(struct se_cmd *se_cmd)
{
1380
	struct se_session *se_sess = se_cmd->se_sess;
1381

1382
	percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
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
}

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)
{
1441 1442
	struct vscsibk_pend *pending_req = container_of(se_cmd,
				struct vscsibk_pend, se_cmd);
1443

1444
	complete(&pending_req->tmr_done);
1445 1446 1447 1448 1449 1450
}

static void scsiback_aborted_task(struct se_cmd *se_cmd)
{
}

1451
static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1452 1453
					     char *page)
{
1454
	struct se_portal_group *se_tpg = param_to_tpg(item);
1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
	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;
}

1466
static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1467 1468
					      const char *page, size_t count)
{
1469
	struct se_portal_group *se_tpg = param_to_tpg(item);
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
	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;
}

1489
CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1490 1491

static struct configfs_attribute *scsiback_param_attrs[] = {
1492
	&scsiback_tpg_param_attr_alias,
1493 1494 1495
	NULL,
};

1496 1497 1498 1499 1500 1501 1502 1503 1504 1505
static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
				  struct se_session *se_sess, void *p)
{
	struct scsiback_tpg *tpg = container_of(se_tpg,
				struct scsiback_tpg, se_tpg);

	tpg->tpg_nexus = p;
	return 0;
}

1506 1507 1508 1509
static int scsiback_make_nexus(struct scsiback_tpg *tpg,
				const char *name)
{
	struct scsiback_nexus *tv_nexus;
1510
	int ret = 0;
1511 1512 1513 1514

	mutex_lock(&tpg->tv_tpg_mutex);
	if (tpg->tpg_nexus) {
		pr_debug("tpg->tpg_nexus already exists\n");
1515 1516
		ret = -EEXIST;
		goto out_unlock;
1517 1518 1519 1520
	}

	tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
	if (!tv_nexus) {
1521 1522
		ret = -ENOMEM;
		goto out_unlock;
1523
	}
1524

1525 1526 1527
	tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg,
						     VSCSI_DEFAULT_SESSION_TAGS,
						     sizeof(struct vscsibk_pend),
1528 1529
						     TARGET_PROT_NORMAL, name,
						     tv_nexus, scsiback_alloc_sess_cb);
1530 1531
	if (IS_ERR(tv_nexus->tvn_se_sess)) {
		kfree(tv_nexus);
1532 1533
		ret = -ENOMEM;
		goto out_unlock;
1534 1535
	}

1536
out_unlock:
1537
	mutex_unlock(&tpg->tv_tpg_mutex);
1538
	return ret;
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
}

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;
	}

1573
	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
		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;
}

1588
static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1589
{
1590
	struct se_portal_group *se_tpg = to_tpg(item);
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608
	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;
}

1609 1610
static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
		const char *page, size_t count)
1611
{
1612
	struct se_portal_group *se_tpg = to_tpg(item);
1613 1614 1615 1616 1617 1618
	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;
	/*
1619
	 * Shutdown the active I_T nexus if 'NULL' is passed.
1620 1621 1622 1623 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
	 */
	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;
}

1684
CONFIGFS_ATTR(scsiback_tpg_, nexus);
1685 1686

static struct configfs_attribute *scsiback_tpg_attrs[] = {
1687
	&scsiback_tpg_attr_nexus,
1688 1689 1690 1691
	NULL,
};

static ssize_t
1692
scsiback_wwn_version_show(struct config_item *item, char *page)
1693 1694 1695 1696 1697 1698
{
	return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
		UTS_RELEASE"\n",
		VSCSI_VERSION, utsname()->sysname, utsname()->machine);
}

1699
CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1700 1701

static struct configfs_attribute *scsiback_wwn_attrs[] = {
1702
	&scsiback_wwn_attr_version,
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
	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;
1744
	u16 tpgt;
1745 1746 1747 1748
	int ret;

	if (strstr(name, "tpgt_") != name)
		return ERR_PTR(-EINVAL);
1749 1750 1751
	ret = kstrtou16(name + 5, 10, &tpgt);
	if (ret)
		return ERR_PTR(ret);
1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762

	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;

1763
	ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
	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);
	/*
1788
	 * Deregister the se_tpg from TCM.
1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803
	 */
	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;
}

1804 1805 1806
static const struct target_core_fabric_ops scsiback_ops = {
	.module				= THIS_MODULE,
	.name				= "xen-pvscsi",
1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836
	.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,
	.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,

1837 1838 1839
	.tfc_wwn_attrs			= scsiback_wwn_attrs,
	.tfc_tpg_base_attrs		= scsiback_tpg_attrs,
	.tfc_tpg_param_attrs		= scsiback_param_attrs,
1840 1841 1842 1843 1844 1845 1846
};

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

1847 1848
static struct xenbus_driver scsiback_driver = {
	.ids			= scsiback_ids,
1849 1850 1851
	.probe			= scsiback_probe,
	.remove			= scsiback_remove,
	.otherend_changed	= scsiback_frontend_changed
1852
};
1853 1854 1855 1856 1857 1858 1859 1860

static int __init scsiback_init(void)
{
	int ret;

	if (!xen_domain())
		return -ENODEV;

1861 1862 1863
	pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);

1864 1865
	ret = xenbus_register_backend(&scsiback_driver);
	if (ret)
1866
		goto out;
1867

1868
	ret = target_register_template(&scsiback_ops);
1869 1870 1871 1872 1873 1874 1875
	if (ret)
		goto out_unregister_xenbus;

	return 0;

out_unregister_xenbus:
	xenbus_unregister_driver(&scsiback_driver);
1876
out:
1877
	pr_err("%s: error %d\n", __func__, ret);
1878 1879 1880 1881 1882 1883 1884 1885 1886 1887
	return ret;
}

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

	while (free_pages_num) {
		if (get_free_page(&page))
			BUG();
1888
		gnttab_free_pages(1, &page);
1889
	}
1890
	target_unregister_template(&scsiback_ops);
1891 1892 1893 1894 1895 1896 1897 1898 1899 1900
	xenbus_unregister_driver(&scsiback_driver);
}

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>");