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[Xen-changelog] [linux-2.6.18-xen] pvSCSI backend driver



# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1212397107 -3600
# Node ID 66faefe721ebb4c9490f3b06b653386d9d2ad4af
# Parent  557a4a0a5eacb83ffb2808c66fd9674e8e26f3e0
pvSCSI backend driver

Signed-off-by: Tomonari Horikoshi <t.horikoshi@xxxxxxxxxxxxxx>
Signed-off-by: Jun Kamada <kama@xxxxxxxxxxxxxx>
---
 buildconfigs/linux-defconfig_xen0_ia64   |    1 
 buildconfigs/linux-defconfig_xen0_x86_32 |    1 
 buildconfigs/linux-defconfig_xen0_x86_64 |    1 
 buildconfigs/linux-defconfig_xen_ia64    |    1 
 buildconfigs/linux-defconfig_xen_x86_32  |    1 
 buildconfigs/linux-defconfig_xen_x86_64  |    1 
 drivers/xen/Kconfig                      |   10 
 drivers/xen/Makefile                     |    1 
 drivers/xen/scsiback/Makefile            |    4 
 drivers/xen/scsiback/common.h            |  181 +++++++
 drivers/xen/scsiback/emulate.c           |  275 +++++++++++
 drivers/xen/scsiback/interface.c         |  184 +++++++
 drivers/xen/scsiback/scsiback.c          |  734 +++++++++++++++++++++++++++++++
 drivers/xen/scsiback/translate.c         |  166 +++++++
 drivers/xen/scsiback/xenbus.c            |  365 +++++++++++++++
 15 files changed, 1925 insertions(+), 1 deletion(-)

diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen0_ia64
--- a/buildconfigs/linux-defconfig_xen0_ia64    Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen0_ia64    Mon Jun 02 09:58:27 2008 +0100
@@ -1681,6 +1681,7 @@ CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER=y
 CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER=y
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 CONFIG_XEN_TPMDEV_BACKEND=m
+CONFIG_XEN_SCSI_BACKEND=m
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen0_x86_32
--- a/buildconfigs/linux-defconfig_xen0_x86_32  Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen0_x86_32  Mon Jun 02 09:58:27 2008 +0100
@@ -1418,6 +1418,7 @@ CONFIG_XEN_PCIDEV_BACKEND_PASS=y
 # CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER is not set
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 CONFIG_XEN_TPMDEV_BACKEND=m
+CONFIG_XEN_SCSI_BACKEND=m
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen0_x86_64
--- a/buildconfigs/linux-defconfig_xen0_x86_64  Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen0_x86_64  Mon Jun 02 09:58:27 2008 +0100
@@ -1359,6 +1359,7 @@ CONFIG_XEN_PCIDEV_BACKEND_PASS=y
 # CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER is not set
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 # CONFIG_XEN_TPMDEV_BACKEND is not set
+# CONFIG_XEN_SCSI_BACKEND is not set
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen_ia64
--- a/buildconfigs/linux-defconfig_xen_ia64     Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen_ia64     Mon Jun 02 09:58:27 2008 +0100
@@ -1681,6 +1681,7 @@ CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER=y
 CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER=y
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 CONFIG_XEN_TPMDEV_BACKEND=m
+CONFIG_XEN_SCSI_BACKEND=m
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen_x86_32
--- a/buildconfigs/linux-defconfig_xen_x86_32   Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen_x86_32   Mon Jun 02 09:58:27 2008 +0100
@@ -3276,6 +3276,7 @@ CONFIG_XEN_PCIDEV_BACKEND_VPCI=y
 # CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER is not set
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 CONFIG_XEN_TPMDEV_BACKEND=m
+CONFIG_XEN_SCSI_BACKEND=m
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb buildconfigs/linux-defconfig_xen_x86_64
--- a/buildconfigs/linux-defconfig_xen_x86_64   Fri May 30 19:08:50 2008 +0100
+++ b/buildconfigs/linux-defconfig_xen_x86_64   Mon Jun 02 09:58:27 2008 +0100
@@ -3106,6 +3106,7 @@ CONFIG_XEN_PCIDEV_BACKEND_PASS=y
 # CONFIG_XEN_PCIDEV_BACKEND_CONTROLLER is not set
 # CONFIG_XEN_PCIDEV_BE_DEBUG is not set
 CONFIG_XEN_TPMDEV_BACKEND=m
+CONFIG_XEN_SCSI_BACKEND=m
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_GRANT_DEV=y
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/Kconfig
--- a/drivers/xen/Kconfig       Fri May 30 19:08:50 2008 +0100
+++ b/drivers/xen/Kconfig       Mon Jun 02 09:58:27 2008 +0100
@@ -166,9 +166,17 @@ config XEN_TPMDEV_BACKEND
        help
          The TPM-device backend driver
 
+config XEN_SCSI_BACKEND
+       tristate "SCSI backend driver"
+       depends on XEN_BACKEND
+       default n
+       help
+         The SCSI backend driver allows the kernel to export its SCSI Devices
+         to other guests via a high-performance shared-memory interface.
+
 config XEN_BLKDEV_FRONTEND
        tristate "Block-device frontend driver"
-       default y
+       default m
        help
          The block-device frontend driver allows the kernel to access block
          devices mounted within another guest OS. Unless you are building a
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/Makefile
--- a/drivers/xen/Makefile      Fri May 30 19:08:50 2008 +0100
+++ b/drivers/xen/Makefile      Mon Jun 02 09:58:27 2008 +0100
@@ -16,6 +16,7 @@ obj-$(CONFIG_XEN_PCIDEV_FRONTEND)     += pci
 obj-$(CONFIG_XEN_PCIDEV_FRONTEND)      += pcifront/
 obj-$(CONFIG_XEN_FRAMEBUFFER)          += fbfront/
 obj-$(CONFIG_XEN_KEYBOARD)             += fbfront/
+obj-$(CONFIG_XEN_SCSI_BACKEND)         += scsiback/
 obj-$(CONFIG_XEN_PRIVCMD)      += privcmd/
 obj-$(CONFIG_XEN_GRANT_DEV)    += gntdev/
 obj-$(CONFIG_XEN_NETDEV_ACCEL_SFC_UTIL)                += sfc_netutil/
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/Makefile
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/Makefile     Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,4 @@
+obj-$(CONFIG_XEN_SCSI_BACKEND) := xen-scsibk.o
+
+xen-scsibk-y   := interface.o scsiback.o xenbus.o translate.o
+
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/common.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/common.h     Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,181 @@
+/*
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * Based on the blkback driver code.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __SCSIIF__BACKEND__COMMON_H__
+#define __SCSIIF__BACKEND__COMMON_H__
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/kthread.h>
+#include <linux/blkdev.h>
+#include <linux/list.h>
+#include <linux/kthread.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_eh.h>
+#include <asm/io.h>
+#include <asm/setup.h>
+#include <asm/pgalloc.h>
+#include <asm/delay.h>
+#include <xen/evtchn.h>
+#include <asm/hypervisor.h>
+#include <xen/gnttab.h>
+#include <xen/driver_util.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/ring.h>
+#include <xen/interface/grant_table.h>
+#include <xen/interface/io/vscsiif.h>
+
+
+
+#define DPRINTK(_f, _a...)                     \
+       pr_debug("(file=%s, line=%d) " _f,      \
+                __FILE__ , __LINE__ , ## _a )
+
+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 scsi_device *sdev;       /* translate to   */
+       struct list_head l;
+};
+
+struct vscsibk_info {
+       struct xenbus_device *dev;
+
+       domid_t domid;
+       unsigned int evtchn;
+       unsigned int irq;
+
+       struct vscsiif_back_ring  ring;
+       struct vm_struct *ring_area;
+       grant_handle_t shmem_handle;
+       grant_ref_t shmem_ref;
+
+       spinlock_t ring_lock;
+       atomic_t refcnt;
+
+       spinlock_t v2p_lock;
+       struct list_head v2p_entry_lists;
+
+       struct task_struct *kthread;
+       wait_queue_head_t waiting_to_free;
+       wait_queue_head_t wq;
+       unsigned int waiting_reqs;
+       struct page **mmap_pages;
+
+};
+
+typedef struct {
+       unsigned char act;
+       struct vscsibk_info *info;
+       struct scsi_device *sdev;
+
+       uint16_t rqid;
+       
+       vscsiif_request_t *ring_req;
+       
+       uint8_t nr_segments;
+       uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
+       uint8_t cmd_len;
+
+       uint8_t sc_data_direction;
+       uint16_t timeout_per_command;
+       
+       uint32_t request_bufflen;
+       struct scatterlist *sgl;
+       grant_ref_t gref[VSCSIIF_SENSE_BUFFERSIZE];
+
+       int32_t rslt;
+       uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
+
+       struct list_head free_list;
+} pending_req_t;
+
+
+
+#define scsiback_get(_b) (atomic_inc(&(_b)->refcnt))
+#define scsiback_put(_b)                               \
+       do {                                            \
+               if (atomic_dec_and_test(&(_b)->refcnt)) \
+                       wake_up(&(_b)->waiting_to_free);\
+       } while (0)
+
+#define VSCSIIF_TIMEOUT                (900*HZ)
+
+
+irqreturn_t scsiback_intr(int, void *, struct pt_regs *);
+int scsiback_init_sring(struct vscsibk_info *info,
+               unsigned long ring_ref, unsigned int evtchn);
+int scsiback_schedule(void *data);
+
+
+struct vscsibk_info *vscsibk_info_alloc(domid_t domid);
+void scsiback_free(struct vscsibk_info *info);
+void scsiback_disconnect(struct vscsibk_info *info);
+int __init scsiback_interface_init(void);
+void __exit scsiback_interface_exit(void);
+int scsiback_xenbus_init(void);
+void scsiback_xenbus_unregister(void);
+
+void scsiback_init_translation_table(struct vscsibk_info *info);
+
+int scsiback_add_translation_entry(struct vscsibk_info *info,
+                       struct scsi_device *sdev, struct ids_tuple *v);
+
+int scsiback_del_translation_entry(struct vscsibk_info *info,
+                               struct ids_tuple *v);
+struct scsi_device *scsiback_do_translation(struct vscsibk_info *info,
+                       struct ids_tuple *v);
+void scsiback_release_translation_entry(struct vscsibk_info *info);
+
+
+void scsiback_cmd_exec(pending_req_t *pending_req);
+
+#if 0 /*SAMPLE CODING(tentative)*//*emulation*/
+void scsiback_dispatch_emulation_cmdexec(vscsiif_request_t *ring_req,
+                               pending_req_t *pending_req);
+#endif
+
+
+#endif /* __SCSIIF__BACKEND__COMMON_H__ */
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/emulate.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/emulate.c    Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,275 @@
+/*
+ * Xen SCSI backend driver
+ *
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * 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.
+ */
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include "comback.h"
+
+/* Following SCSI commands are not defined in scsi/scsi.h */
+#define EXTENDED_COPY          0x83    /* EXTENDED COPY command        */
+#define REPORT_ALIASES         0xa3    /* REPORT ALIASES command       */
+#define CHANGE_ALIASES         0xa4    /* CHANGE ALIASES command       */
+#define SET_PRIORITY           0xa4    /* SET PRIORITY command         */
+
+
+/*
+  The bitmap in order to control emulation.
+  (Bit 3 to 7 are reserved for future use.)
+*/
+#define VSCSIIF_NEED_CMD_EXEC          0x01    /* If this bit is set, cmd exec 
*/
+                                               /* is required.                 
*/
+#define VSCSIIF_NEED_EMULATE_REQBUF    0x02    /* If this bit is set, need     
*/
+                                               /* emulation reqest buff before 
*/
+                                               /* cmd exec.                    
*/
+#define VSCSIIF_NEED_EMULATE_RSPBUF    0x04    /* If this bit is set, need     
*/
+                                               /* emulation resp buff after    
*/
+                                               /* cmd exec.                    
*/
+
+/* Additional Sense Code (ASC) used */
+#define NO_ADDITIONAL_SENSE            0x0
+#define LOGICAL_UNIT_NOT_READY         0x4
+#define UNRECOVERED_READ_ERR           0x11
+#define PARAMETER_LIST_LENGTH_ERR      0x1a
+#define INVALID_OPCODE                 0x20
+#define ADDR_OUT_OF_RANGE              0x21
+#define INVALID_FIELD_IN_CDB           0x24
+#define INVALID_FIELD_IN_PARAM_LIST    0x26
+#define POWERON_RESET                  0x29
+#define SAVING_PARAMS_UNSUP            0x39
+#define THRESHOLD_EXCEEDED             0x5d
+#define LOW_POWER_COND_ON              0x5e
+
+
+
+/* Number os SCSI op_code      */
+#define VSCSI_MAX_SCSI_OP_CODE         256
+static unsigned char bitmap[VSCSI_MAX_SCSI_OP_CODE];
+
+/*
+  Emulation routines for each SCSI op_code.
+*/
+static void (*pre_function[MAX_SCSI_OP_CODE])(pending_request_t *, void *);
+static void (*post_function[MAX_SCSI_OP_CODE])(pending_request_t *, void *);
+
+
+static const int check_condition_result =
+               (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
+
+
+static int __copy_to_sg(struct scatterlist *sg, unsigned int nr_sg,
+              void *buf, unsigned int buflen)
+{
+       void *from = buf;
+       void *to;
+       unsigned int from_rest = buflen;
+       unsigned int to_capa;
+       unsigned int copy_size;
+       unsigned int i;
+
+       for (i = 0; i < nr_sg; i++) {
+               if (sg->page == NULL) {
+                       printk(KERN_WARN "%s: inconsistent length field in "
+                              "scatterlist\n", __FUNCTION__);
+                       return -1;
+               }
+
+               to_capa  = sg->length;
+               copy_size = min_t(to_capa, from_rest);
+
+               to = page_to_virt(sg->page) + (sg->offset);
+               memcpy(to, from, copy_size);
+
+               from_rest  -= copy_size;
+               if (from_rest == 0) {
+                       return 0;
+               }
+               
+               sg++;
+               from += copy_size;
+       }
+
+       printk(KERN_WARN "%s: no space in scatterlist\n",
+              __FUNCTION__);
+       return -1;
+}
+
+static int __copy_from_sg(struct scatterlist *sg, unsigned int nr_sg,
+                void *buf, unsigned int buflen)
+{
+       void *from;
+       void *to = buf;
+       unsigned int from_rest;
+       unsigned int to_capa = buflen;
+       unsigned int copy_size;
+       unsigned int i;
+
+       for (i = 0; i < nr_sg; i++) {
+               if (sg->page == NULL) {
+                       printk(KERN_WARN "%s: inconsistent length field in "
+                              "scatterlist\n", __FUNCTION__);
+                       return -1;
+               }
+
+               from_rest = sg->length;
+               if ((from_rest > 0) && (to_capa < from_rest)) {
+                       printk(KERN_WARN
+                              "%s: no space in destination buffer\n",
+                              __FUNCTION__);
+                       return -1;
+               }
+               copy_size = from_rest;
+
+               from = page_to_virt(sg->page) + (sg->offset);
+               memcpy(to, from, copy_size);
+
+               to_capa  -= copy_size;
+               
+               sg++;
+               to += copy_size;
+       }
+
+       return 0;
+}
+
+
+static void scsiback_mk_sense_buffer(uint8_t *date, uint8_t key, uint8_t asc,
+                               utint_8 asq)
+{
+       data[0] = 0x70;  /* fixed, current */
+       data[2] = key;
+       data[7] = 0xa;    /* implies 18 byte sense buffer */
+       data[12] = asc;
+       data[13] = asq;
+}
+
+
+
+/* tuning point*/
+#define VSCSIIF_RLUN_ARR_SZ            2048
+
+/* quoted scsi_debug.c/resp_report_luns() */
+static void __report_luns(pending_request_t *pending_req, void *data)
+{
+       struct vscsibk_info *info   = pending_req->info;
+       unsigned int        channel = pending_req->sdev->channel;
+       unsigned int        target  = pending_req->sdev->id;
+       unsigned char *cmd = (unsigned char *)pending_req->cmnd;
+       
+       unsigned char rq_buff[VSCSIIF_RLUN_ARR_SZ];
+       unsigned char *sense_buf = pending_req->sense_buffer;
+       unsigned char alloc_len;
+       int select_report = (int)cmd[2];
+       int lun_cnt = 0;
+       
+       struct v2p_entry *entry;
+       struct list_head *head = &(info->v2p_entry_lists);
+       unsigned long flags;
+       
+       struct scsi_lun *one_lun;
+
+       alloc_len = cmd[9] + (cmd[8] << 8) + (cmd[7] << 16) + (cmd[6] << 24);
+       if ((alloc_len < 4) || (select_report != 0)) {
+               scsiback_mk_sense_buffer(pending_req->sense_buffer, 
ILLEGAL_REQUEST,
+                       INVALID_FIELD_IN_CDB, 0);
+               pending_req->rslt = check_condition_result;
+               return;
+       }
+
+       memset(rq_buff, 0, VSCSIIF_RLUN_ARR_SZ);
+       __copy_from_sg(pending_req->sgl, pending_req->nr_segments,
+               rq_buff, VSCSIIF_RLUN_ARR_SZ);
+
+
+       rq_buff[2] = ((sizeof(struct scsi_lun) * num) >> 8) & 0xff;
+       rq_buff[3] = (sizeof(struct scsi_lun) * num) & 0xff;
+
+
+       one_lun = (struct scsi_lun *) &rq_buff[8];
+       spin_lock_irqsave(&info->v2p_lock, flags);
+       list_for_each_entry(entry, head, l) {
+               if ((entry->v.chn == channel) &&
+                   (entry->v.tgt == target) {
+                       lun = entry->v.lun;
+                       upper = (lun >> 8) & 0x3f;
+                       if (upper)
+                               one_lun[lun_cnt].scsi_lun[0] = upper;
+                       one_lun[lun_cnt].scsi_lun[1] = lun & 0xff;
+                       lun_cnt++;
+               }
+       }
+       spin_unlock_irqrestore(&info->v2p_lock, flags);
+
+
+       lun_alloc = (unsigned char *)(one_lun + lun_cnt) - rq_buff;
+       
+       return fill_from_dev_buffer(scp, rq_buff,
+                                   min((int)alloc_len, lun_alloc));
+}
+
+
+
+int __pre_do_emulation(pending_request_t *pending_req, void *data)
+{
+       uint8_t op_code = pending_req->cmnd[0];
+
+       if ((bitmap[op_code] & VSCSIIF_NEED_EMULATE_REQBUF) &&
+           pre_function[op_code] != NULL) {
+               pre_function[op_code](pending_req, data);
+       }
+
+       /*
+           0: no need for native driver call, so should return immediately.
+           1: non emulation or should call native driver 
+              after modifing the request buffer.
+       */
+       return (bitmap[op_code] & VSCSIIF_NEED_CMD_EXEC);
+}
+
+void scsiback_rsp_emulation(pending_request_t *pending_req)
+{
+       uint8_t op_code = pending_req->cdb[0];
+
+       if ((bitmap[op_code] & VSCSIIF_NEED_EMULATE_RSPBUF) &&
+           post_function[op_code] != NULL) {
+               post_function[op_code](pending_req, NULL);
+       }
+
+       return;
+}
+
+
+void scsiback_req_emulation_or_cmdexec(pending_req_t *pending_req)
+{
+       if (__pre_do_emulation(pending_req, NULL))
+               scsiback_cmd_exec(pending_req);
+       else 
+               scsiback_do_resp_with_sense(pending_req);
+}
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/interface.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/interface.c  Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,184 @@
+/*
+ * interface management.
+ *
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * Based on the blkback driver code.
+ *
+ * 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.
+ */
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include "common.h"
+
+#include <xen/evtchn.h>
+#include <linux/kthread.h>
+
+
+static kmem_cache_t *scsiback_cachep;
+
+struct vscsibk_info *vscsibk_info_alloc(domid_t domid)
+{
+       struct vscsibk_info *info;
+
+       info = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
+       if (!info)
+               return ERR_PTR(-ENOMEM);
+
+       memset(info, 0, sizeof(*info));
+       info->domid = domid;
+       spin_lock_init(&info->ring_lock);
+       atomic_set(&info->refcnt, 1);
+       init_waitqueue_head(&info->wq);
+       init_waitqueue_head(&info->waiting_to_free);
+
+       return info;
+}
+
+static int map_frontend_page( struct vscsibk_info *info,
+                               unsigned long ring_ref)
+{
+       struct gnttab_map_grant_ref op;
+       int err;
+
+       gnttab_set_map_op(&op, (unsigned long)info->ring_area->addr,
+                               GNTMAP_host_map, ring_ref,
+                               info->domid);
+
+       err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
+       BUG_ON(err);
+
+       if (op.status) {
+               printk(KERN_ERR "scsiback: Grant table operation failure !\n");
+               return op.status;
+       }
+
+       info->shmem_ref    = ring_ref;
+       info->shmem_handle = op.handle;
+
+       return 0;
+}
+
+static void unmap_frontend_page(struct vscsibk_info *info)
+{
+       struct gnttab_unmap_grant_ref op;
+       int err;
+
+       gnttab_set_unmap_op(&op, (unsigned long)info->ring_area->addr,
+                               GNTMAP_host_map, info->shmem_handle);
+
+       err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
+       BUG_ON(err);
+
+}
+
+int scsiback_init_sring(struct vscsibk_info *info,
+               unsigned long ring_ref, unsigned int evtchn)
+{
+       struct vscsiif_sring *sring;
+       int err;
+
+       if (info->irq) {
+               printk(KERN_ERR "scsiback: Already connected through?\n");
+               return 0;
+       }
+
+       info->ring_area = alloc_vm_area(PAGE_SIZE);
+       if (!info)
+               return -ENOMEM;
+
+       err = map_frontend_page(info, ring_ref);
+       if (err)
+               goto free_vm;
+
+       sring = (struct vscsiif_sring *) info->ring_area->addr;
+       BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
+
+       err = bind_interdomain_evtchn_to_irqhandler(
+                       info->domid, evtchn,
+                       scsiback_intr, 0, "vscsiif-backend", info);
+
+       if (err < 0)
+               goto unmap_page;
+               
+       info->irq = err;
+       
+       return 0;
+
+unmap_page:
+       unmap_frontend_page(info);
+free_vm:
+       free_vm_area(info->ring_area);
+
+       return err;
+}
+
+void scsiback_disconnect(struct vscsibk_info *info)
+{
+       if (info->kthread) {
+               kthread_stop(info->kthread);
+               info->kthread = NULL;
+       }
+
+       atomic_dec(&info->refcnt);
+       wait_event(info->waiting_to_free, atomic_read(&info->refcnt) == 0);
+       atomic_inc(&info->refcnt);
+
+       if (info->irq) {
+               unbind_from_irqhandler(info->irq, info);
+               info->irq = 0;
+       }
+
+       if (info->ring.sring) {
+               unmap_frontend_page(info);
+               free_vm_area(info->ring_area);
+               info->ring.sring = NULL;
+       }
+}
+
+void scsiback_free(struct vscsibk_info *info)
+{
+       if (atomic_dec_and_test(&info->refcnt))
+               kmem_cache_free(scsiback_cachep, info);
+}
+
+int __init scsiback_interface_init(void)
+{
+       scsiback_cachep = kmem_cache_create("vscsiif_cache",
+               sizeof(struct vscsibk_info), 0, 0, NULL, NULL);
+       if (!scsiback_cachep) {
+               printk(KERN_ERR "scsiback: can't init scsi cache\n");
+               return -ENOMEM;
+       }
+       
+       return 0;
+}
+
+void __exit scsiback_interface_exit(void)
+{
+       kmem_cache_destroy(scsiback_cachep);
+}
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/scsiback.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/scsiback.c   Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,734 @@
+/*
+ * Xen SCSI backend driver
+ *
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * Based on the blkback driver code.
+ *
+ * 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.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/delay.h>
+#include <xen/balloon.h>
+#include <asm/hypervisor.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_eh.h>
+
+#include "common.h"
+
+
+#define  NO_ASYNC  1 /*!aync*/
+
+struct list_head pending_free;
+DEFINE_SPINLOCK(pending_free_lock);
+DECLARE_WAIT_QUEUE_HEAD(pending_free_wq);
+
+int vscsiif_reqs = VSCSIIF_BACK_MAX_PENDING_REQS;
+module_param_named(reqs, vscsiif_reqs, int, 0);
+MODULE_PARM_DESC(reqs, "Number of scsiback requests to allocate");
+
+
+#define SCSIBACK_INVALID_HANDLE (~0)
+
+static pending_req_t *pending_reqs;
+static struct page **pending_pages;
+static grant_handle_t *pending_grant_handles;
+
+static int vaddr_pagenr(pending_req_t *req, int seg)
+{
+       return (req - pending_reqs) * VSCSIIF_SG_TABLESIZE + seg;
+}
+
+static unsigned long vaddr(pending_req_t *req, int seg)
+{
+       unsigned long pfn = page_to_pfn(pending_pages[vaddr_pagenr(req, seg)]);
+       return (unsigned long)pfn_to_kaddr(pfn);
+}
+
+#define pending_handle(_req, _seg) \
+       (pending_grant_handles[vaddr_pagenr(_req, _seg)])
+
+
+static void fast_flush_area(pending_req_t *req)
+{
+       struct gnttab_unmap_grant_ref unmap[VSCSIIF_SG_TABLESIZE];
+       unsigned int i, invcount = 0;
+       grant_handle_t handle;
+       int err;
+
+       if (req->nr_segments) {
+               for (i = 0; i < req->nr_segments; i++) {
+                       handle = pending_handle(req, i);
+                       if (handle == SCSIBACK_INVALID_HANDLE)
+                               continue;
+                       gnttab_set_unmap_op(&unmap[i], vaddr(req, i),
+                                               GNTMAP_host_map, handle);
+                       pending_handle(req, i) = SCSIBACK_INVALID_HANDLE;
+                       invcount++;
+               }
+
+               err = HYPERVISOR_grant_table_op(
+                       GNTTABOP_unmap_grant_ref, unmap, invcount);
+               BUG_ON(err);
+               kfree(req->sgl);
+       }
+
+       return;
+}
+
+
+static pending_req_t * alloc_req(struct vscsibk_info *info)
+{
+       pending_req_t *req = NULL;
+       unsigned long flags;
+
+       spin_lock_irqsave(&pending_free_lock, flags);
+       if (!list_empty(&pending_free)) {
+               req = list_entry(pending_free.next, pending_req_t, free_list);
+               list_del(&req->free_list);
+       }
+       spin_unlock_irqrestore(&pending_free_lock, flags);
+       return req;
+}
+
+
+static void free_req(pending_req_t *req)
+{
+       unsigned long flags;
+       int was_empty;
+
+       spin_lock_irqsave(&pending_free_lock, flags);
+       was_empty = list_empty(&pending_free);
+       list_add(&req->free_list, &pending_free);
+       spin_unlock_irqrestore(&pending_free_lock, flags);
+       if (was_empty)
+               wake_up(&pending_free_wq);
+}
+
+
+static void scsiback_notify_work(struct vscsibk_info *info)
+{
+       info->waiting_reqs = 1;
+       wake_up(&info->wq);
+}
+
+static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
+                               pending_req_t *pending_req)
+{
+       vscsiif_response_t *ring_res;
+       struct vscsibk_info *info = pending_req->info;
+       int notify;
+       int more_to_do = 1;
+       unsigned long flags;
+
+       DPRINTK("%s\n",__FUNCTION__);
+
+       spin_lock_irqsave(&info->ring_lock, flags);
+
+       rmb();
+       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) {
+               memcpy(ring_res->sense_buffer, sense_buffer,
+                               VSCSIIF_SENSE_BUFFERSIZE);
+               ring_res->sense_len = VSCSIIF_SENSE_BUFFERSIZE;
+       } else {
+               ring_res->sense_len = 0;
+       }
+
+       RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
+       if (info->ring.rsp_prod_pvt == info->ring.req_cons) {
+               RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
+       } else if (RING_HAS_UNCONSUMED_REQUESTS(&info->ring)) {
+               more_to_do = 1;
+       }
+       
+       spin_unlock_irqrestore(&info->ring_lock, flags);
+
+       if (more_to_do)
+               scsiback_notify_work(info);
+
+       if (notify)
+               notify_remote_via_irq(info->irq);
+
+       scsiback_put(pending_req->info);
+       free_req(pending_req);
+}
+
+#ifdef NO_ASYNC /*!async*/
+static void scsiback_cmd_done(struct request *req, int errors)
+{
+       pending_req_t *pending_req = req->end_io_data;
+       struct scsi_device *sdev = pending_req->sdev;
+       unsigned char *sense_buffer;
+
+       sense_buffer = req->sense;
+
+#else
+static void scsiback_cmd_done(void *data, char *sense_buffer,
+                               int errors, int resid)
+{
+       pending_req_t *pending_req = data;
+       struct scsi_device *sdev = pending_req->sdev;
+
+       DPRINTK("%s\n",__FUNCTION__);
+#endif
+
+       if ((errors != 0) && (pending_req->cmnd[0] != TEST_UNIT_READY)) {
+
+               printk(KERN_ERR "scsiback: %d:%d:%d:%d ",sdev->host->host_no,
+                               sdev->channel, sdev->id, sdev->lun);
+               printk(KERN_ERR "status = 0x%02x, message = 0x%02x, host = 
0x%02x, driver = 0x%02x\n",
+                               status_byte(errors), msg_byte(errors),
+                               host_byte(errors), driver_byte(errors));
+
+               printk(KERN_ERR "scsiback: cmnd[0]=0x%02X nr_segments=%d\n",
+                               pending_req->cmnd[0],
+                               pending_req->nr_segments);
+
+               if (CHECK_CONDITION & status_byte(errors))
+                       __scsi_print_sense("scsiback", sense_buffer, 
SCSI_SENSE_BUFFERSIZE);
+       }
+
+#if 0 /*SAMPLE CODING(tentative)*//*emulation*/
+       scsiback_rsp_emulation(pending_req);
+#endif
+       fast_flush_area(pending_req);
+       scsiback_do_resp_with_sense(sense_buffer, errors, pending_req);
+
+
+#ifdef NO_ASYNC /*!async*/
+       __blk_put_request(req->q, req);
+#endif
+}
+
+
+static int scsiback_gnttab_data_map(vscsiif_request_t *ring_req,
+                                       pending_req_t *pending_req)
+{
+       u32 flags;
+       int write;
+       int i, err = 0;
+       unsigned int data_len = 0;
+       struct gnttab_map_grant_ref map[VSCSIIF_SG_TABLESIZE];
+       struct vscsibk_info *info   = pending_req->info;
+
+       int data_dir = (int)pending_req->sc_data_direction;
+       unsigned int nr_segments = (unsigned int)pending_req->nr_segments;
+
+       write = (data_dir == DMA_TO_DEVICE);
+
+       if (nr_segments) {
+               /* free of (sgl) in fast_flush_area()*/
+               pending_req->sgl = kmalloc(sizeof(struct scatterlist) * 
nr_segments,
+                                               GFP_KERNEL);
+               if (!pending_req->sgl) {
+                       printk(KERN_ERR "scsiback: %s: kmalloc() error.\n", 
__FUNCTION__);
+                       return -ENOMEM;
+               }
+
+               for (i = 0; i < nr_segments; i++) {
+                       flags = GNTMAP_host_map;
+                       if (write)
+                               flags |= GNTMAP_readonly;
+                       gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
+                                               ring_req->seg[i].gref,
+                                               info->domid);
+               }
+
+               err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, 
nr_segments);
+               BUG_ON(err);
+
+               for (i = 0; i < nr_segments; i++) {
+                       if (unlikely(map[i].status != 0)) {
+                               printk(KERN_ERR "scsiback: invalid buffer -- 
could not remap it\n");
+                               map[i].handle = SCSIBACK_INVALID_HANDLE;
+                               err |= 1;
+                       }
+
+                       pending_handle(pending_req, i) = map[i].handle;
+
+                       if (err)
+                               continue;
+
+                       set_phys_to_machine(__pa(vaddr(
+                               pending_req, i)) >> PAGE_SHIFT,
+                               FOREIGN_FRAME(map[i].dev_bus_addr >> 
PAGE_SHIFT));
+
+                       pending_req->sgl[i].page   = 
virt_to_page(vaddr(pending_req, i));
+                       pending_req->sgl[i].offset = ring_req->seg[i].offset;
+                       pending_req->sgl[i].length = ring_req->seg[i].length;
+                       data_len += pending_req->sgl[i].length;
+               }
+
+               if (err)
+                       goto fail_flush;
+       }
+       
+       pending_req->request_bufflen = data_len;
+       
+       return 0;
+       
+fail_flush:
+       fast_flush_area(pending_req);
+       return -ENOMEM;
+}
+
+
+#ifdef NO_ASYNC /*!async*/
+
+/* quoted scsi_lib.c/scsi_merge_bio */
+static int scsiback_merge_bio(struct request *rq, struct bio *bio)
+{
+       struct request_queue *q = rq->q;
+
+       bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+       if (rq_data_dir(rq) == WRITE)
+               bio->bi_rw |= (1 << BIO_RW);
+
+       blk_queue_bounce(q, &bio);
+
+       if (!rq->bio)
+               blk_rq_bio_prep(q, rq, bio);
+       else if (!q->back_merge_fn(q, rq, bio))
+               return -EINVAL;
+       else {
+               rq->biotail->bi_next = bio;
+               rq->biotail          = bio;
+               rq->hard_nr_sectors += bio_sectors(bio);
+               rq->nr_sectors       = rq->hard_nr_sectors;
+       }
+
+       return 0;
+}
+
+
+/* quoted scsi_lib.c/scsi_bi_endio */
+static int scsiback_bi_endio(struct bio *bio, unsigned int bytes_done, int 
error)
+{
+       if (bio->bi_size)
+               return 1;
+
+       bio_put(bio);
+       return 0;
+}
+
+
+
+/* quoted scsi_lib.c/scsi_req_map_sg . */
+static int requset_map_sg(struct request *rq, pending_req_t *pending_req, 
unsigned int count)
+{
+       struct request_queue *q = rq->q;
+       int nr_pages;
+       unsigned int nsegs = count;
+
+       unsigned int data_len = 0, len, bytes, off;
+       struct page *page;
+       struct bio *bio = NULL;
+       int i, err, nr_vecs = 0;
+
+       for (i = 0; i < nsegs; i++) {
+               page = pending_req->sgl[i].page;
+               off = (unsigned int)pending_req->sgl[i].offset;
+               len = (unsigned int)pending_req->sgl[i].length;
+               data_len += len;
+
+               nr_pages = (len + off + PAGE_SIZE - 1) >> PAGE_SHIFT;
+               while (len > 0) {
+                       bytes = min_t(unsigned int, len, PAGE_SIZE - off);
+
+                       if (!bio) {
+                               nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
+                               nr_pages -= nr_vecs;
+                               bio = bio_alloc(GFP_KERNEL, nr_vecs);
+                               if (!bio) {
+                                       err = -ENOMEM;
+                                       goto free_bios;
+                               }
+                               bio->bi_end_io = scsiback_bi_endio;
+                       }
+
+                       if (bio_add_pc_page(q, bio, page, bytes, off) !=
+                                               bytes) {
+                               bio_put(bio);
+                               err = -EINVAL;
+                               goto free_bios;
+                       }
+
+                       if (bio->bi_vcnt >= nr_vecs) {
+                               err = scsiback_merge_bio(rq, bio);
+                               if (err) {
+                                       bio_endio(bio, bio->bi_size, 0);
+                                       goto free_bios;
+                               }
+                               bio = NULL;
+                       }
+
+                       page++;
+                       len -= bytes;
+                       off = 0;
+               }
+       }
+
+       rq->buffer   = rq->data = NULL;
+       rq->data_len = data_len;
+
+       return 0;
+
+free_bios:
+       while ((bio = rq->bio) != NULL) {
+               rq->bio = bio->bi_next;
+               /*
+                * call endio instead of bio_put incase it was bounced
+                */
+               bio_endio(bio, bio->bi_size, 0);
+       }
+
+       return err;
+}
+
+#endif
+
+void scsiback_cmd_exec(pending_req_t *pending_req)
+{
+       int err;
+
+       int cmd_len  = (int)pending_req->cmd_len;
+       int data_dir = (int)pending_req->sc_data_direction;
+       unsigned int nr_segments = (unsigned int)pending_req->nr_segments;
+       unsigned int timeout;
+#ifdef NO_ASYNC /*!async*/
+       struct request *rq;
+       int write;
+#else
+       unsigned int data_len = pending_req->request_bufflen;
+#endif
+
+       DPRINTK("%s\n",__FUNCTION__);
+
+       /* because it doesn't timeout backend earlier than frontend.*/
+       if (pending_req->timeout_per_command)
+               timeout = (pending_req->timeout_per_command * HZ * 2);
+       else
+               timeout = VSCSIIF_TIMEOUT;
+
+#ifdef NO_ASYNC /*!async*/
+       err = 0;
+       write = (data_dir == DMA_TO_DEVICE);
+       rq = blk_get_request(pending_req->sdev->request_queue, write, 
GFP_KERNEL);
+
+       rq->flags  |= REQ_BLOCK_PC;
+       rq->cmd_len = cmd_len;
+       memcpy(rq->cmd, pending_req->cmnd, cmd_len);
+
+       memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
+       rq->sense       = pending_req->sense_buffer;
+       rq->sense_len = 0;
+
+       rq->retries   = 0;
+       rq->timeout   = timeout;
+       rq->end_io_data = pending_req;
+
+       if (nr_segments) {
+
+               if (requset_map_sg(rq, pending_req, nr_segments)) {
+                       printk(KERN_ERR "scsiback: SG Request Map Error\n");
+                       return;
+               }
+       }
+
+       blk_execute_rq_nowait(rq->q, NULL, rq, 1, scsiback_cmd_done);
+
+#else   /*async*/
+       /* not allowed to retry in backend.                   */
+       /* timeout of backend is longer than that of brontend.*/
+       err = scsi_execute_async(pending_req->sdev, &(pending_req->cmnd[0]),
+               cmd_len, data_dir, &(pending_req->sgl[0]), data_len, 
nr_segments, timeout, 0,
+               pending_req, scsiback_cmd_done, GFP_ATOMIC);
+               
+#endif /*!async*/
+
+       if (err) 
+               scsiback_do_resp_with_sense(NULL, (DRIVER_ERROR << 24), 
pending_req);
+
+       return ;
+}
+
+
+static void scsiback_device_reset_exec(pending_req_t *pending_req)
+{
+       struct vscsibk_info *info = pending_req->info;
+       int err;
+       struct scsi_device *sdev = pending_req->sdev;
+
+       scsiback_get(info);
+
+       err = scsi_reset_provider(sdev, SCSI_TRY_RESET_DEVICE);
+
+       scsiback_do_resp_with_sense(NULL, err, pending_req);
+
+       notify_remote_via_irq(info->irq);
+       return;
+}
+
+
+irqreturn_t scsiback_intr(int irq, void *dev_id, struct pt_regs *regs)
+{
+       scsiback_notify_work((struct vscsibk_info *)dev_id);
+       return IRQ_HANDLED;
+}
+
+static int prepare_pending_reqs(struct vscsibk_info *info,
+               vscsiif_request_t *ring_req, pending_req_t *pending_req)
+{
+       struct scsi_device *sdev;
+       struct ids_tuple vir;
+       int err = -EINVAL;
+
+       DPRINTK("%s\n",__FUNCTION__);
+
+       pending_req->rqid       = ring_req->rqid;
+       pending_req->act        = ring_req->act;
+
+       pending_req->info       = info;
+
+       vir.chn = ring_req->channel;
+       vir.tgt = ring_req->id;
+       vir.lun = ring_req->lun;
+
+       sdev = scsiback_do_translation(info, &vir);
+       if (!sdev) {
+               pending_req->sdev = NULL;
+               printk(KERN_ERR "scsiback: doesn't exist.\n");
+               err = -ENODEV;
+               goto invald_value;
+       }
+       pending_req->sdev = sdev;
+
+       /* 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)) {
+               printk(KERN_ERR "scsiback: invalid parameter data_dir = %d\n",
+                       ring_req->sc_data_direction);
+               err = -EINVAL;
+               goto invald_value;
+       }
+
+       if (ring_req->nr_segments > VSCSIIF_SG_TABLESIZE) {
+               printk(KERN_ERR "scsiback: invalid parameter nr_seg = %d\n",
+                       ring_req->nr_segments);
+               err = -EINVAL;
+               goto invald_value;
+       }
+       pending_req->nr_segments = ring_req->nr_segments;
+
+       if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
+               printk(KERN_ERR "scsiback: invalid parameter cmd_len = %d\n",
+                       ring_req->cmd_len);
+               err = -EINVAL;
+               goto invald_value;
+       }
+       memcpy(pending_req->cmnd, ring_req->cmnd, ring_req->cmd_len);
+       pending_req->cmd_len = ring_req->cmd_len;
+       
+       pending_req->sc_data_direction = ring_req->sc_data_direction;
+       pending_req->timeout_per_command = ring_req->timeout_per_command;
+
+       if(scsiback_gnttab_data_map(ring_req, pending_req)) {
+               printk(KERN_ERR "scsiback: invalid buffer\n");
+               err = -EINVAL;
+               goto invald_value;
+       }
+
+       return 0;
+
+invald_value:
+       return err;
+}
+
+
+static int scsiback_do_cmd_fn(struct vscsibk_info *info)
+{
+       struct vscsiif_back_ring *ring = &info->ring;
+       vscsiif_request_t  *ring_req;
+
+       pending_req_t *pending_req;
+       RING_IDX rc, rp;
+       int err, more_to_do = 0;
+
+       DPRINTK("%s\n",__FUNCTION__);
+
+       rc = ring->req_cons;
+       rp = ring->sring->req_prod;
+       rmb();
+
+       while ((rc != rp)) {
+               if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
+                       break;
+               pending_req = alloc_req(info);
+               if (NULL == pending_req) {
+                       more_to_do = 1;
+                       break;
+               }
+
+               ring_req = RING_GET_REQUEST(ring, rc);
+               ring->req_cons = ++rc;
+
+               scsiback_get(info);
+               err = prepare_pending_reqs(info, ring_req,
+                                               pending_req);
+               if (err == -EINVAL) {
+                       scsiback_do_resp_with_sense(NULL, (DRIVER_ERROR << 24),
+                               pending_req);
+                       continue;
+               } else if (err == -ENODEV) {
+                       scsiback_do_resp_with_sense(NULL, (DID_NO_CONNECT << 
16),
+                               pending_req);                   
+               }
+
+               if (pending_req->act == VSCSIIF_ACT_SCSI_CDB) {
+#if 0 /*SAMPLE CODING(tentative)*//*emulation*/
+                       scsiback_req_emulation_or_through(pending_req);
+#else
+                       scsiback_cmd_exec(pending_req);
+#endif
+               } else if (pending_req->act == VSCSIIF_ACT_SCSI_RESET) {
+                       scsiback_device_reset_exec(pending_req);
+               } else {
+                       printk(KERN_ERR "scsiback: invalid parameter for 
request\n");
+                       scsiback_do_resp_with_sense(NULL, (DRIVER_ERROR << 24),
+                               pending_req);
+                       continue;
+               }
+       }
+
+       if (RING_HAS_UNCONSUMED_REQUESTS(ring))
+               more_to_do = 1;
+
+       return more_to_do;
+}
+
+
+int scsiback_schedule(void *data)
+{
+       struct vscsibk_info *info = (struct vscsibk_info *)data;
+
+       DPRINTK("%s\n",__FUNCTION__);
+
+       scsiback_get(info);
+
+       while (!kthread_should_stop()) {
+               wait_event_interruptible(
+                       info->wq,
+                       info->waiting_reqs || kthread_should_stop());
+               wait_event_interruptible(
+                       pending_free_wq,
+                       !list_empty(&pending_free) || kthread_should_stop());
+
+               info->waiting_reqs = 0;
+               smp_mb();
+
+               if (scsiback_do_cmd_fn(info))
+                       info->waiting_reqs = 1;
+       }
+
+       info->kthread = NULL;
+       scsiback_put(info);
+
+       return 0;
+}
+
+
+static int __init scsiback_init(void)
+{
+       int i, mmap_pages;
+
+       if (!is_running_on_xen())
+               return -ENODEV;
+
+       mmap_pages = vscsiif_reqs * VSCSIIF_SG_TABLESIZE;
+
+       pending_reqs          = kmalloc(sizeof(pending_reqs[0]) *
+                                       vscsiif_reqs, GFP_KERNEL);
+       pending_grant_handles = kmalloc(sizeof(pending_grant_handles[0]) *
+                                       mmap_pages, GFP_KERNEL);
+       pending_pages         = alloc_empty_pages_and_pagevec(mmap_pages);
+
+       if (!pending_reqs || !pending_grant_handles || !pending_pages)
+               goto out_of_memory;
+
+       for (i = 0; i < mmap_pages; i++)
+               pending_grant_handles[i] = SCSIBACK_INVALID_HANDLE;
+
+       if (scsiback_interface_init() < 0)
+               goto out_of_memory;
+
+       memset(pending_reqs, 0, sizeof(pending_reqs));
+       INIT_LIST_HEAD(&pending_free);
+
+       for (i = 0; i < vscsiif_reqs; i++)
+               list_add_tail(&pending_reqs[i].free_list, &pending_free);
+
+       if (scsiback_xenbus_init())
+               goto out_of_memory;
+
+       return 0;
+
+out_of_memory:
+       kfree(pending_reqs);
+       kfree(pending_grant_handles);
+       free_empty_pages_and_pagevec(pending_pages, mmap_pages);
+       printk(KERN_ERR "scsiback: %s: out of memory\n", __FUNCTION__);
+       return -ENOMEM;
+}
+
+static void __exit scsiback_exit(void)
+{
+       scsiback_xenbus_unregister();
+       scsiback_interface_exit();
+       kfree(pending_reqs);
+       kfree(pending_grant_handles);
+       free_empty_pages_and_pagevec(pending_pages, (vscsiif_reqs * 
VSCSIIF_SG_TABLESIZE));
+
+}
+
+module_init(scsiback_init);
+module_exit(scsiback_exit);
+
+MODULE_DESCRIPTION("Xen SCSI backend driver");
+MODULE_LICENSE("Dual BSD/GPL");
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/translate.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/translate.c  Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,166 @@
+/*
+ * Xen SCSI backend driver
+ *
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * 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.
+ */
+
+#include <linux/list.h>
+#include <linux/gfp.h>
+
+#include "common.h"
+
+/*
+  Initialize the translation entry list
+*/
+void scsiback_init_translation_table(struct vscsibk_info *info)
+{
+       INIT_LIST_HEAD(&info->v2p_entry_lists);
+       spin_lock_init(&info->v2p_lock);
+}
+
+
+/*
+  Add a new translation entry
+*/
+int scsiback_add_translation_entry(struct vscsibk_info *info,
+                       struct scsi_device *sdev, 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;
+       
+       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)) {
+                       printk(KERN_WARNING "scsiback: Virtual ID is already 
used. "
+                              "Assignment was not performed.\n");
+                       err = -EEXIST;
+                       goto out;
+               }
+
+       }
+
+       /* Create a new translation entry and add to the list */
+       if ((new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL)) == NULL) {
+               printk(KERN_ERR "scsiback: %s: kmalloc() error.\n", 
__FUNCTION__);
+               err = -ENOMEM;
+               goto out;
+       }
+       new->v = *v;
+       new->sdev = sdev;
+       list_add(&new->l, head);
+
+out:   
+       spin_unlock_irqrestore(&info->v2p_lock, flags);
+       return err;
+}
+
+
+/*
+  Delete the translation entry specfied
+*/
+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 0;
+
+found:
+       /* Delete the translation entry specfied */
+       list_del(&entry->l);
+       kfree(entry);
+
+       spin_unlock_irqrestore(&info->v2p_lock, flags);
+       return 0;
+}
+
+
+/*
+  Perform virtual to physical translation
+*/
+struct scsi_device *scsiback_do_translation(struct vscsibk_info *info,
+                       struct ids_tuple *v)
+{
+       struct v2p_entry *entry;
+       struct list_head *head = &(info->v2p_entry_lists);
+       struct scsi_device *sdev = NULL;
+       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)) {
+                       sdev = entry->sdev;
+                       goto out;
+               }
+       }
+out:
+       spin_unlock_irqrestore(&info->v2p_lock, flags);
+       return sdev;
+}
+
+
+/*
+  Release the translation entry specfied
+*/
+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) {
+               list_del(&entry->l);
+               kfree(entry);
+       }
+
+       spin_unlock_irqrestore(&info->v2p_lock, flags);
+       return;
+
+}
diff -r 557a4a0a5eac -r 66faefe721eb drivers/xen/scsiback/xenbus.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/scsiback/xenbus.c     Mon Jun 02 09:58:27 2008 +0100
@@ -0,0 +1,365 @@
+/*
+ * Xen SCSI backend driver
+ *
+ * Copyright (c) 2008, FUJITSU Limited
+ *
+ * Based on the blkback driver code.
+ *
+ * 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.
+ */
+
+#include <stdarg.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+
+#include "common.h"
+
+struct backend_info
+{
+       struct xenbus_device *dev;
+       struct vscsibk_info *info;
+};
+
+
+static int __vscsiif_name(struct backend_info *be, char *buf)
+{
+       struct xenbus_device *dev = be->dev;
+       unsigned int domid, id;
+
+       sscanf(dev->nodename, "backend/vscsi/%u/%u", &domid, &id);
+       snprintf(buf, TASK_COMM_LEN, "vscsi.%u.%u", be->info->domid, id);
+
+       return 0;
+}
+
+static int scsiback_map(struct backend_info *be)
+{
+       struct xenbus_device *dev = be->dev;
+       unsigned long ring_ref;
+       unsigned int evtchn;
+       int err;
+       char name[TASK_COMM_LEN];
+
+       err = xenbus_gather(XBT_NIL, dev->otherend,
+                       "ring-ref", "%lu", &ring_ref,
+                       "event-channel", "%u", &evtchn, NULL);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
+               return err;
+       }
+
+       err = scsiback_init_sring(be->info, ring_ref, evtchn);
+       if (err)
+               return err;
+
+       err = __vscsiif_name(be, name);
+       if (err) {
+               xenbus_dev_error(dev, err, "get scsiback dev name");
+               return err;
+       }
+
+       be->info->kthread = kthread_run(scsiback_schedule, be->info, name);
+       if (IS_ERR(be->info->kthread)) {
+               err = PTR_ERR(be->info->kthread);
+               be->info->kthread = NULL;
+               xenbus_dev_error(be->dev, err, "start vscsiif");
+               return err;
+       }
+
+       return 0;
+}
+
+
+struct scsi_device *scsiback_get_scsi_device(struct ids_tuple *phy)
+{
+       struct Scsi_Host *shost;
+       struct scsi_device *sdev = NULL;
+
+       shost = scsi_host_lookup(phy->hst);
+       if (IS_ERR(shost)) {
+               printk(KERN_ERR "scsiback: host%d doesn't exist.\n",
+                       phy->hst);
+               goto invald_value;
+       }
+       sdev   = scsi_device_lookup(shost, phy->chn, phy->tgt, phy->lun);
+       if (!sdev) {
+               printk(KERN_ERR "scsiback: %d:%d:%d:%d doesn't exist.\n",
+                       phy->hst, phy->chn, phy->tgt, phy->lun);
+               goto invald_value;
+       }
+
+invald_value:
+       return (sdev);
+}
+
+#define VSCSIBACK_OP_ADD_OR_DEL_LUN    1
+
+static void scsiback_do_lun_hotplug(struct backend_info *be, int op)
+{
+       int i, err = 0;
+       struct ids_tuple phy, vir;
+       int device_state;
+       char str[64], state_str[64];
+       char **dir;
+       unsigned int dir_n = 0;
+       struct xenbus_device *dev = be->dev;
+       struct scsi_device *sdev;
+       struct xenbus_transaction xbt;
+
+
+       err = xenbus_transaction_start(&xbt);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "starting transaction");
+       }
+
+       dir = xenbus_directory(xbt, dev->nodename, "vscsi-devs", &dir_n);
+       if (IS_ERR(dir))
+               return;
+
+       for (i = 0; i < dir_n; i++) {
+               
+               /* read status */
+               snprintf(state_str, sizeof(state_str), "vscsi-devs/%s/state", 
dir[i]);
+               err = xenbus_scanf(xbt, dev->nodename, state_str, "%u",
+                       &device_state);
+               if (XENBUS_EXIST_ERR(err))
+                       continue;
+
+               /* physical SCSI device */
+               snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", dir[i]);
+               err = xenbus_scanf(xbt, dev->nodename, str,
+                       "%u:%u:%u:%u", &phy.hst, &phy.chn, &phy.tgt, &phy.lun);
+               if (XENBUS_EXIST_ERR(err)) {
+                       xenbus_printf(xbt, dev->nodename, state_str,
+                                       "%d", XenbusStateClosing);
+                       continue;
+               }
+
+               /* virtual SCSI device */
+               snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]);
+               err = xenbus_scanf(xbt, dev->nodename, str,
+                       "%u:%u:%u:%u", &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
+               if (XENBUS_EXIST_ERR(err)) {
+                       xenbus_printf(xbt, dev->nodename, state_str,
+                                       "%d", XenbusStateClosing);
+                       continue;
+               }
+
+               switch (op) {
+               case VSCSIBACK_OP_ADD_OR_DEL_LUN:
+                       if (device_state == XenbusStateInitialising) {
+                               sdev = scsiback_get_scsi_device(&phy);
+                               if (!sdev) {
+                                       xenbus_printf(xbt, dev->nodename, 
state_str,
+                                                       "%d", 
XenbusStateClosing);
+                               } else {
+                                       err = 
scsiback_add_translation_entry(be->info, sdev, &vir);
+                                       if (!err) {
+                                               xenbus_printf(xbt, 
dev->nodename, state_str,
+                                                       "%d", 
XenbusStateInitialised);
+                                       } else {
+                                               xenbus_printf(xbt, 
dev->nodename, state_str,
+                                                       "%d", 
XenbusStateClosing);                                              
+                                       }
+                               }
+                       }
+
+                       if (device_state == XenbusStateClosing) {
+                               err = scsiback_del_translation_entry(be->info, 
&vir);
+                               if (err)
+                                       goto fail;
+                               else {
+                                       xenbus_printf(xbt, dev->nodename, 
state_str,
+                                               "%d", XenbusStateClosed);       
                                        
+                               }
+                       }
+
+                       break;
+               /*When it is necessary, processing is added here.*/
+               default:
+                       break;
+               }
+       }
+
+       xenbus_transaction_end(xbt, 0);
+       kfree(dir);
+       return ;
+fail :
+       xenbus_transaction_end(xbt, 1);
+       kfree(dir);
+       xenbus_dev_fatal(dev, err, "read or write %s ", str);
+       return;
+}
+
+
+static void scsiback_frontend_changed(struct xenbus_device *dev,
+                                       enum xenbus_state frontend_state)
+{
+       struct backend_info *be = dev->dev.driver_data;
+       int err;
+
+       switch (frontend_state) {
+       case XenbusStateInitialising:
+               break;
+       case XenbusStateInitialised:
+               err = scsiback_map(be);
+               if (err)
+                       break;
+
+               scsiback_do_lun_hotplug(be, VSCSIBACK_OP_ADD_OR_DEL_LUN);
+               err = xenbus_switch_state(dev, XenbusStateConnected);
+               if (err)
+                       xenbus_dev_fatal(dev, err, "switching to Connected 
state",
+                                       dev->nodename);
+               break;
+       case XenbusStateConnected:
+               if (dev->state == XenbusStateConnected)
+                       break;
+                       
+               err = xenbus_switch_state(dev, XenbusStateConnected);
+               if (err)
+                       xenbus_dev_fatal(dev, err, "switching to Connected 
state",
+                                       dev->nodename);
+               break;
+
+       case XenbusStateClosing:
+               scsiback_disconnect(be->info);
+               xenbus_switch_state(dev, XenbusStateClosing);
+               break;
+
+       case XenbusStateClosed:
+               xenbus_switch_state(dev, XenbusStateClosed);
+               if (xenbus_dev_is_online(dev))
+                       break;
+
+       case XenbusStateReconfiguring:
+               scsiback_do_lun_hotplug(be, VSCSIBACK_OP_ADD_OR_DEL_LUN);
+               err = xenbus_switch_state(dev, XenbusStateReconfigured);
+               if (err)
+                       xenbus_dev_fatal(dev, err, "switching to Reconfigured 
state",
+                                       dev->nodename);
+               break;
+
+       case XenbusStateUnknown:
+               device_unregister(&dev->dev);
+               break;
+       default:
+               xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
+                                       frontend_state);
+               break;
+       }
+}
+
+
+static int scsiback_remove(struct xenbus_device *dev)
+{
+       struct backend_info *be = dev->dev.driver_data;
+
+       if (be->info) {
+               scsiback_disconnect(be->info);
+               scsiback_release_translation_entry(be->info);
+               scsiback_free(be->info);
+               be->info = NULL;
+       }
+
+       kfree(be);
+       dev->dev.driver_data = NULL;
+
+       return 0;
+}
+
+
+static int scsiback_probe(struct xenbus_device *dev,
+                          const struct xenbus_device_id *id)
+{
+       int err;
+
+       struct backend_info *be = kzalloc(sizeof(struct backend_info),
+                                         GFP_KERNEL);
+
+       DPRINTK("%p %d\n", dev, dev->otherend_id);
+
+       if (!be) {
+               xenbus_dev_fatal(dev, -ENOMEM,
+                                "allocating backend structure");
+               return -ENOMEM;
+       }
+       be->dev = dev;
+       dev->dev.driver_data = be;
+
+       be->info = vscsibk_info_alloc(dev->otherend_id);
+       if (IS_ERR(be->info)) {
+               err = PTR_ERR(be->info);
+               be->info = NULL;
+               xenbus_dev_fatal(dev, err, "creating scsihost interface");
+               goto fail;
+       }
+
+       be->info->dev = dev;
+       be->info->irq = 0;
+
+       scsiback_init_translation_table(be->info);
+
+       err = xenbus_switch_state(dev, XenbusStateInitWait);
+       if (err)
+               goto fail;
+
+       return 0;
+
+
+fail:
+       printk(KERN_WARNING "scsiback: %s failed\n",__FUNCTION__);
+       scsiback_remove(dev);
+
+       return err;
+}
+
+
+static struct xenbus_device_id scsiback_ids[] = {
+       { "vscsi" },
+       { "" }
+};
+
+static struct xenbus_driver scsiback = {
+       .name                   = "vscsi",
+       .owner                  = THIS_MODULE,
+       .ids                    = scsiback_ids,
+       .probe                  = scsiback_probe,
+       .remove                 = scsiback_remove,
+       .otherend_changed       = scsiback_frontend_changed
+};
+
+int scsiback_xenbus_init(void)
+{
+       return xenbus_register_backend(&scsiback);
+}
+
+void scsiback_xenbus_unregister(void)
+{
+       xenbus_unregister_driver(&scsiback);
+}

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