[PATCH 3/4] Introduce XEN scsiback module

jgross
2014-06-27T14:35:35Z

From: Juergen Gross <jgross@suse.com>

Introduces the XEN pvSCSI backend. With pvSCSI it is possible for a XEN domU
to issue SCSI commands to a SCSI LUN assigned to that domU. The SCSI commands
are passed to the pvSCSI backend in a driver domain (usually Dom0) which is
owner of the physical device. This allows e.g. to use SCSI tape drives in a
XEN domU.

The code is taken from the pvSCSI implementation in XEN done by Fujitsu based
on Linux kernel 2.6.18.

Changes from the original version are:
- port to upstream kernel
- put all code in just one source file
- move module to appropriate location in kernel tree
- adapt to Linux style guide
- correct minor error in scsiback_fast_flush_area
- some minor code simplifications

Signed-off-by: Juergen Gross <jgross@suse.com>
---
drivers/scsi/Kconfig | 7 +
drivers/scsi/Makefile | 1 +
drivers/scsi/xen-scsiback.c | 1797 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1805 insertions(+)
create mode 100644 drivers/scsi/xen-scsiback.c

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 734d691..ccd8ba0 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -611,6 +611,13 @@ config VMWARE_PVSCSI
To compile this driver as a module, choose M here: the
module will be called vmw_pvscsi.

+config XEN_SCSI_BACKEND
+ tristate "XEN SCSI backend driver"
+ depends on SCSI && XEN && XEN_BACKEND
+ 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_SCSI_FRONTEND
tristate "XEN SCSI frontend driver"
depends on SCSI && XEN
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index a4ee9c5..4cfcc3a 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -156,6 +156,7 @@ obj-$(CONFIG_BLK_DEV_SR) += sr_mod.o
obj-$(CONFIG_CHR_DEV_SG) += sg.o
obj-$(CONFIG_CHR_DEV_SCH) += ch.o
obj-$(CONFIG_SCSI_ENCLOSURE) += ses.o
+obj-$(CONFIG_XEN_SCSI_BACKEND) += xen-scsiback.o

obj-$(CONFIG_SCSI_OSD_INITIATOR) += osd/

diff --git a/drivers/scsi/xen-scsiback.c b/drivers/scsi/xen-scsiback.c
new file mode 100644
index 0000000..5b85e6f
--- /dev/null
+++ b/drivers/scsi/xen-scsiback.c
@@ -0,0 +1,1797 @@
+/*
+ * 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.
+ */
+
+/*
+* Patched to support >2TB drives + allow tape & autoloader operations
+* 2010, Samuel Kvasnica, IMS Nanofabrication AG
+*/
+
+#include <stdarg.h>
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/blkdev.h>
+#include <linux/list.h>
+#include <linux/gfp.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/vmalloc.h>
+#include <linux/spinlock.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/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 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;
+
+ int feature;
+
+ struct vscsiif_back_ring ring;
+
+ spinlock_t ring_lock;
+ atomic_t nr_unreplied_reqs;
+
+ 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;
+ wait_queue_head_t shutdown_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;
+
+ uint16_t v_chn, v_tgt;
+
+ 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_SG_TABLESIZE];
+
+ int32_t rslt;
+ uint32_t resid;
+ uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
+
+ struct list_head free_list;
+} pending_req_t;
+
+struct backend_info
+{
+ struct xenbus_device *dev;
+ struct vscsibk_info *info;
+};
+
+#define scsiback_get(_b) (atomic_inc(&(_b)->nr_unreplied_reqs))
+#define scsiback_put(_b) \
+ do { \
+ if (atomic_dec_and_test(&(_b)->nr_unreplied_reqs)) \
+ wake_up(&(_b)->waiting_to_free);\
+ } while (0)
+
+#define VSCSIIF_TIMEOUT (900*HZ)
+
+#define VSCSI_TYPE_HOST 1
+
+/* 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 /* cmd exec required */
+#define VSCSIIF_NEED_EMULATE_REQBUF 0x02 /* emul reqest buff before */
+ /* cmd exec. */
+#define VSCSIIF_NEED_EMULATE_RSPBUF 0x04 /* emul 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];
+
+#define NO_EMULATE(cmd) \
+ bitmap[cmd] = VSCSIIF_NEED_CMD_EXEC; \
+ pre_function[cmd] = NULL; \
+ post_function[cmd] = NULL
+
+#define SCSIBACK_INVALID_HANDLE (~0)
+
+static bool log_print_stat;
+module_param(log_print_stat, bool, 0644);
+
+/*
+ Emulation routines for each SCSI op_code.
+*/
+static void (*pre_function[VSCSI_MAX_SCSI_OP_CODE])(pending_req_t *, void *);
+static void (*post_function[VSCSI_MAX_SCSI_OP_CODE])(pending_req_t *, void *);
+
+static pending_req_t *pending_reqs;
+static struct page **pending_pages;
+static grant_handle_t *pending_grant_handles;
+
+static const int check_condition_result =
+ (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
+
+struct list_head pending_free;
+DEFINE_SPINLOCK(pending_free_lock);
+DECLARE_WAIT_QUEUE_HEAD(pending_free_wq);
+
+static struct kmem_cache *scsiback_cachep;
+
+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);
+}
+
+static void scsiback_mk_sense_buffer(uint8_t *data, uint8_t key,
+ uint8_t asc, uint8_t asq)
+{
+ data[0] = 0x70; /* fixed, current */
+ data[2] = key;
+ data[7] = 0xa; /* implies 18 byte sense buffer */
+ data[12] = asc;
+ data[13] = asq;
+}
+
+static void resp_not_supported_cmd(pending_req_t *pending_req, void *data)
+{
+ scsiback_mk_sense_buffer(pending_req->sense_buffer, ILLEGAL_REQUEST,
+ INVALID_OPCODE, 0);
+ pending_req->resid = 0;
+ pending_req->rslt = check_condition_result;
+}
+
+static int __copy_to_sg(struct scatterlist *sgl, unsigned int nr_sg,
+ void *buf, unsigned int buflen)
+{
+ struct scatterlist *sg;
+ void *from = buf;
+ void *to;
+ unsigned int from_rest = buflen;
+ unsigned int to_capa;
+ unsigned int copy_size = 0;
+ unsigned int i;
+ unsigned long pfn;
+
+ for_each_sg (sgl, sg, nr_sg, i) {
+ if (sg_page(sg) == NULL) {
+ pr_warning("%s: inconsistent length field in "
+ "scatterlist\n", __FUNCTION__);
+ return -ENOMEM;
+ }
+
+ to_capa = sg->length;
+ copy_size = min_t(unsigned int, to_capa, from_rest);
+
+ pfn = page_to_pfn(sg_page(sg));
+ to = pfn_to_kaddr(pfn) + (sg->offset);
+ memcpy(to, from, copy_size);
+
+ from_rest -= copy_size;
+ if (from_rest == 0)
+ return 0;
+
+ from += copy_size;
+ }
+
+ pr_warning("%s: no space in scatterlist\n", __FUNCTION__);
+ return -ENOMEM;
+}
+
+static int __maybe_unused __copy_from_sg(struct scatterlist *sgl,
+ unsigned int nr_sg, void *buf,
+ unsigned int buflen)
+{
+ struct scatterlist *sg;
+ void *from;
+ void *to = buf;
+ unsigned int from_rest;
+ unsigned int to_capa = buflen;
+ unsigned int copy_size;
+ unsigned int i;
+ unsigned long pfn;
+
+ for_each_sg (sgl, sg, nr_sg, i) {
+ if (sg_page(sg) == NULL) {
+ pr_warning("%s: inconsistent length field in "
+ "scatterlist\n", __FUNCTION__);
+ return -ENOMEM;
+ }
+
+ from_rest = sg->length;
+ if ((from_rest > 0) && (to_capa < from_rest)) {
+ pr_warning("%s: no space in destination buffer\n",
+ __FUNCTION__);
+ return -ENOMEM;
+ }
+ copy_size = from_rest;
+
+ pfn = page_to_pfn(sg_page(sg));
+ from = pfn_to_kaddr(pfn) + (sg->offset);
+ memcpy(to, from, copy_size);
+
+ to_capa -= copy_size;
+ to += copy_size;
+ }
+
+ return 0;
+}
+
+static int __nr_luns_under_host(struct vscsibk_info *info)
+{
+ struct v2p_entry *entry;
+ struct list_head *head = &(info->v2p_entry_lists);
+ unsigned long flags;
+ int lun_cnt = 0;
+
+ spin_lock_irqsave(&info->v2p_lock, flags);
+ list_for_each_entry(entry, head, l) {
+ lun_cnt++;
+ }
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+
+ return (lun_cnt);
+}
+
+/* REPORT LUNS Define*/
+#define VSCSI_REPORT_LUNS_HEADER 8
+#define VSCSI_REPORT_LUNS_RETRY 3
+
+/* quoted scsi_debug.c/resp_report_luns() */
+static void __report_luns(pending_req_t *pending_req, void *data)
+{
+ struct vscsibk_info *info = pending_req->info;
+ unsigned int nr_seg = pending_req->nr_segments;
+ unsigned char *cmd = (unsigned char *)pending_req->cmnd;
+ unsigned char *buff = NULL;
+ unsigned char alloc_len;
+ unsigned int alloc_luns = 0;
+ unsigned int req_bufflen = 0;
+ unsigned int actual_len = 0;
+ unsigned int retry_cnt = 0;
+ int select_report = (int)cmd[2];
+ int i, lun_cnt = 0, lun, upper, err = 0;
+
+ struct v2p_entry *entry;
+ struct list_head *head = &(info->v2p_entry_lists);
+ unsigned long flags;
+
+ struct scsi_lun *one_lun;
+
+ req_bufflen = cmd[9] + (cmd[8] << 8) + (cmd[7] << 16) + (cmd[6] << 24);
+ if ((req_bufflen < 4) || (select_report != 0))
+ goto fail;
+
+ alloc_luns = __nr_luns_under_host(info);
+ alloc_len = sizeof(struct scsi_lun) * alloc_luns
+ + VSCSI_REPORT_LUNS_HEADER;
+retry:
+ if ((buff = kzalloc(alloc_len, GFP_KERNEL)) == NULL) {
+ pr_err("scsiback:%s kmalloc err\n", __FUNCTION__);
+ goto fail;
+ }
+
+ one_lun = (struct scsi_lun *) &buff[8];
+ spin_lock_irqsave(&info->v2p_lock, flags);
+ list_for_each_entry(entry, head, l) {
+ if ((entry->v.chn == pending_req->v_chn) &&
+ (entry->v.tgt == pending_req->v_tgt)) {
+
+ /* check overflow */
+ if (lun_cnt >= alloc_luns) {
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+
+ if (retry_cnt < VSCSI_REPORT_LUNS_RETRY) {
+ retry_cnt++;
+ if (buff)
+ kfree(buff);
+ goto retry;
+ }
+
+ goto fail;
+ }
+
+ 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);
+
+ buff[2] = ((sizeof(struct scsi_lun) * lun_cnt) >> 8) & 0xff;
+ buff[3] = (sizeof(struct scsi_lun) * lun_cnt) & 0xff;
+
+ actual_len = lun_cnt * sizeof(struct scsi_lun)
+ + VSCSI_REPORT_LUNS_HEADER;
+ req_bufflen = 0;
+ for (i = 0; i < nr_seg; i++)
+ req_bufflen += pending_req->sgl[i].length;
+
+ err = __copy_to_sg(pending_req->sgl, nr_seg, buff,
+ min(req_bufflen, actual_len));
+ if (err)
+ goto fail;
+
+ memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
+ pending_req->rslt = 0x00;
+ pending_req->resid = req_bufflen - min(req_bufflen, actual_len);
+
+ kfree(buff);
+ return;
+
+fail:
+ scsiback_mk_sense_buffer(pending_req->sense_buffer, ILLEGAL_REQUEST,
+ INVALID_FIELD_IN_CDB, 0);
+ pending_req->rslt = check_condition_result;
+ pending_req->resid = 0;
+ if (buff)
+ kfree(buff);
+ return;
+}
+
+int __pre_do_emulation(pending_req_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);
+}
+
+static void scsiback_rsp_emulation(pending_req_t *pending_req)
+{
+ uint8_t op_code = pending_req->cmnd[0];
+
+ if ((bitmap[op_code] & VSCSIIF_NEED_EMULATE_RSPBUF) &&
+ post_function[op_code] != NULL)
+ post_function[op_code](pending_req, NULL);
+
+ return;
+}
+
+/* quoted scsi_lib.c/scsi_bi_endio */
+static void scsiback_bi_endio(struct bio *bio, int error)
+{
+ bio_put(bio);
+}
+
+/* quoted scsi_lib.c/scsi_req_map_sg . */
+static struct bio *request_map_sg(pending_req_t *pending_req)
+{
+ struct request_queue *q = pending_req->sdev->request_queue;
+ unsigned int nsegs = (unsigned int)pending_req->nr_segments;
+ unsigned int i, len, bytes, off, nr_pages, nr_vecs = 0;
+ struct scatterlist *sg;
+ struct page *page;
+ struct bio *bio = NULL, *bio_first = NULL, *bio_last = NULL;
+ int err;
+
+ for_each_sg (pending_req->sgl, sg, nsegs, i) {
+ page = sg_page(sg);
+ off = sg->offset;
+ len = sg->length;
+
+ 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(unsigned 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_last)
+ bio_last->bi_next = bio;
+ else
+ bio_first = bio;
+ bio_last = bio;
+ }
+
+ if (bio_add_pc_page(q, bio, page, bytes, off) !=
+ bytes) {
+ err = -EINVAL;
+ goto free_bios;
+ }
+
+ if (bio->bi_vcnt >= nr_vecs) {
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+ if (pending_req->sc_data_direction == WRITE)
+ bio->bi_rw |= REQ_WRITE;
+ bio = NULL;
+ }
+
+ page++;
+ len -= bytes;
+ off = 0;
+ }
+ }
+
+ return bio_first;
+
+free_bios:
+ while ((bio = bio_first) != NULL) {
+ bio_first = bio->bi_next;
+ bio_put(bio);
+ }
+
+ return ERR_PTR(err);
+}
+
+static void scsiback_print_status(char *sense_buffer, int errors,
+ pending_req_t *pending_req)
+{
+ struct scsi_device *sdev = pending_req->sdev;
+
+ pr_err("scsiback[%d:%d:%d:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
+ sdev->host->host_no, sdev->channel, sdev->id, sdev->lun,
+ pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
+ host_byte(errors), driver_byte(errors));
+
+ if (CHECK_CONDITION & status_byte(errors))
+ __scsi_print_sense("scsiback", sense_buffer,
+ SCSI_SENSE_BUFFERSIZE);
+}
+
+#define pending_handle(_req, _seg) \
+ (pending_grant_handles[vaddr_pagenr(_req, _seg)])
+
+static void scsiback_fast_flush_area(pending_req_t *req)
+{
+ struct gnttab_unmap_grant_ref unmap[VSCSIIF_SG_TABLESIZE];
+ struct page *pages[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[invcount], vaddr(req, i),
+ GNTMAP_host_map, handle);
+ pending_handle(req, i) = SCSIBACK_INVALID_HANDLE;
+ pages[invcount] = pending_pages[vaddr_pagenr(req, i)];
+ invcount++;
+ }
+
+ err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
+ BUG_ON(err);
+ kfree(req->sgl);
+ }
+
+ return;
+}
+
+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_do_resp_with_sense(char *sense_buffer, int32_t result,
+ uint32_t resid, pending_req_t *pending_req)
+{
+ vscsiif_response_t *ring_res;
+ struct vscsibk_info *info = pending_req->info;
+ int notify;
+ struct scsi_sense_hdr sshdr;
+ unsigned long flags;
+
+ DPRINTK("%s\n",__FUNCTION__);
+
+ spin_lock_irqsave(&info->ring_lock, flags);
+
+ ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
+ info->ring.rsp_prod_pvt++;
+
+ ring_res->rslt = result;
+ ring_res->rqid = pending_req->rqid;
+
+ if (sense_buffer != NULL) {
+ if (scsi_normalize_sense(sense_buffer,
+ sizeof(sense_buffer), &sshdr)) {
+
+ int len = 8 + sense_buffer[7];
+
+ if (len > VSCSIIF_SENSE_BUFFERSIZE)
+ len = 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);
+
+ free_req(pending_req);
+}
+
+static void scsiback_cmd_done(struct request *req, int uptodate)
+{
+ pending_req_t *pending_req = req->end_io_data;
+ unsigned char *sense_buffer;
+ unsigned int resid;
+ int errors;
+
+ sense_buffer = req->sense;
+ resid = blk_rq_bytes(req);
+ errors = req->errors;
+
+ if (errors && log_print_stat)
+ scsiback_print_status(sense_buffer, errors, pending_req);
+
+ /* The Host mode is through as for Emulation. */
+ if (pending_req->info->feature != VSCSI_TYPE_HOST)
+ scsiback_rsp_emulation(pending_req);
+
+ scsiback_fast_flush_area(pending_req);
+ scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
+ scsiback_put(pending_req->info);
+
+ __blk_put_request(req->q, req);
+}
+
+static void scsiback_cmd_exec(pending_req_t *pending_req)
+{
+ int cmd_len = (int)pending_req->cmd_len;
+ int data_dir = (int)pending_req->sc_data_direction;
+ unsigned int timeout;
+ struct bio *bio;
+ struct request *rq;
+ int write;
+
+ 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;
+ else
+ timeout = VSCSIIF_TIMEOUT;
+
+ write = (data_dir == DMA_TO_DEVICE);
+ if (pending_req->nr_segments) {
+ bio = request_map_sg(pending_req);
+ if (IS_ERR(bio)) {
+ pr_err("scsiback: SG Request Map Error %ld\n",
+ PTR_ERR(bio));
+ return;
+ }
+ } else {
+ bio = NULL;
+ }
+
+ if (bio) {
+ rq = blk_make_request(pending_req->sdev->request_queue, bio,
+ GFP_KERNEL);
+ if (IS_ERR(rq)) {
+ pr_err("scsiback: Make Request Error %ld\n",
+ PTR_ERR(rq));
+ return;
+ }
+ } else {
+ rq = blk_get_request(pending_req->sdev->request_queue, write,
+ GFP_KERNEL);
+ if (unlikely(!rq)) {
+ pr_err("scsiback: Get Request Error\n");
+ return;
+ }
+ }
+
+ rq->cmd_type = REQ_TYPE_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;
+
+ /* not allowed to retry in backend. */
+ rq->retries = 0;
+ rq->timeout = timeout;
+ rq->end_io_data = pending_req;
+
+ scsiback_get(pending_req->info);
+ blk_execute_rq_nowait(rq->q, NULL, rq, 1, scsiback_cmd_done);
+
+ return ;
+}
+
+static 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_fast_flush_area(pending_req);
+ scsiback_do_resp_with_sense(pending_req->sense_buffer,
+ pending_req->rslt, pending_req->resid, pending_req);
+ }
+}
+
+
+/*
+ Following are not customizable functions.
+*/
+static void scsiback_emulation_init(void)
+{
+ int i;
+
+ /* Initialize to default state */
+ for (i = 0; i < VSCSI_MAX_SCSI_OP_CODE; i++) {
+ bitmap[i] = VSCSIIF_NEED_EMULATE_REQBUF |
+ VSCSIIF_NEED_EMULATE_RSPBUF;
+ pre_function[i] = resp_not_supported_cmd;
+ post_function[i] = NULL;
+ /* means,
+ - no need for pre-emulation
+ - no need for post-emulation
+ - call native driver
+ */
+ }
+
+ /*
+ Register appropriate functions below as you need.
+ (See scsi/scsi.h for definition of SCSI op_code.)
+ */
+
+ /*
+ Following commands do not require emulation.
+ */
+ NO_EMULATE(TEST_UNIT_READY); /*0x00*/ /* sd,st */
+ NO_EMULATE(REZERO_UNIT); /*0x01*/ /* st */
+ NO_EMULATE(REQUEST_SENSE); /*0x03*/
+ NO_EMULATE(FORMAT_UNIT); /*0x04*/
+ NO_EMULATE(READ_BLOCK_LIMITS); /*0x05*/ /* st */
+ /*NO_EMULATE(REASSIGN_BLOCKS); *//*0x07*/
+ NO_EMULATE(INITIALIZE_ELEMENT_STATUS); /*0x07*/ /* ch */
+ NO_EMULATE(READ_6); /*0x08*/ /* sd,st */
+ NO_EMULATE(WRITE_6); /*0x0a*/ /* sd,st */
+ NO_EMULATE(SEEK_6); /*0x0b*/
+ /*NO_EMULATE(READ_REVERSE); *//*0x0f*/
+ NO_EMULATE(WRITE_FILEMARKS); /*0x10*/ /* st */
+ NO_EMULATE(SPACE); /*0x11*/ /* st */
+ NO_EMULATE(INQUIRY); /*0x12*/
+ /*NO_EMULATE(RECOVER_BUFFERED_DATA); *//*0x14*/
+ NO_EMULATE(MODE_SELECT); /*0x15*/ /* st */
+ NO_EMULATE(RESERVE); /*0x16*/
+ NO_EMULATE(RELEASE); /*0x17*/
+ /*NO_EMULATE(COPY); *//*0x18*/
+ NO_EMULATE(ERASE); /*0x19*/ /* st */
+ NO_EMULATE(MODE_SENSE); /*0x1a*/ /* st */
+ NO_EMULATE(START_STOP); /*0x1b*/ /* sd,st */
+ NO_EMULATE(RECEIVE_DIAGNOSTIC); /*0x1c*/
+ NO_EMULATE(SEND_DIAGNOSTIC); /*0x1d*/
+ NO_EMULATE(ALLOW_MEDIUM_REMOVAL); /*0x1e*/
+
+ /*NO_EMULATE(SET_WINDOW); *//*0x24*/
+ NO_EMULATE(READ_CAPACITY); /*0x25*/ /* sd */
+ NO_EMULATE(READ_10); /*0x28*/ /* sd */
+ NO_EMULATE(WRITE_10); /*0x2a*/ /* sd */
+ NO_EMULATE(SEEK_10); /*0x2b*/ /* st */
+ NO_EMULATE(POSITION_TO_ELEMENT); /*0x2b*/ /* ch */
+ /*NO_EMULATE(WRITE_VERIFY); *//*0x2e*/
+ /*NO_EMULATE(VERIFY); *//*0x2f*/
+ /*NO_EMULATE(SEARCH_HIGH); *//*0x30*/
+ /*NO_EMULATE(SEARCH_EQUAL); *//*0x31*/
+ /*NO_EMULATE(SEARCH_LOW); *//*0x32*/
+ NO_EMULATE(SET_LIMITS); /*0x33*/
+ NO_EMULATE(PRE_FETCH); /*0x34*/ /* st! */
+ NO_EMULATE(READ_POSITION); /*0x34*/ /* st */
+ NO_EMULATE(SYNCHRONIZE_CACHE); /*0x35*/ /* sd */
+ NO_EMULATE(LOCK_UNLOCK_CACHE); /*0x36*/
+ NO_EMULATE(READ_DEFECT_DATA); /*0x37*/
+ NO_EMULATE(MEDIUM_SCAN); /*0x38*/
+ /*NO_EMULATE(COMPARE); *//*0x39*/
+ /*NO_EMULATE(COPY_VERIFY); *//*0x3a*/
+ NO_EMULATE(WRITE_BUFFER); /*0x3b*/
+ NO_EMULATE(READ_BUFFER); /*0x3c*/ /* osst */
+ /*NO_EMULATE(UPDATE_BLOCK); *//*0x3d*/
+ /*NO_EMULATE(READ_LONG); *//*0x3e*/
+ /*NO_EMULATE(WRITE_LONG); *//*0x3f*/
+ /*NO_EMULATE(CHANGE_DEFINITION); *//*0x40*/
+ /*NO_EMULATE(WRITE_SAME); *//*0x41*/
+ NO_EMULATE(READ_TOC); /*0x43*/ /* sr */
+ NO_EMULATE(LOG_SELECT); /*0x4c*/
+ NO_EMULATE(LOG_SENSE); /*0x4d*/ /* st! */
+ /*NO_EMULATE(MODE_SELECT_10); *//*0x55*/
+ /*NO_EMULATE(RESERVE_10); *//*0x56*/
+ /*NO_EMULATE(RELEASE_10); *//*0x57*/
+ NO_EMULATE(MODE_SENSE_10); /*0x5a*/ /* scsi_lib */
+ /*NO_EMULATE(PERSISTENT_RESERVE_IN); *//*0x5e*/
+ /*NO_EMULATE(PERSISTENT_RESERVE_OUT); *//*0x5f*/
+ /* REPORT_LUNS *//*0xa0*//*Full emulaiton*/
+#ifdef MAINTENANCE_IN
+ NO_EMULATE(MAINTENANCE_IN); /*0xa3*/ /* IFT alua */
+ NO_EMULATE(MAINTENANCE_OUT); /*0xa4*/ /* IFT alua */
+#endif
+ NO_EMULATE(MOVE_MEDIUM); /*0xa5*/ /* ch */
+ NO_EMULATE(EXCHANGE_MEDIUM); /*0xa6*/ /* ch */
+ /*NO_EMULATE(READ_12); *//*0xa8*/
+ /*NO_EMULATE(WRITE_12); *//*0xaa*/
+ /*NO_EMULATE(WRITE_VERIFY_12); *//*0xae*/
+ /*NO_EMULATE(SEARCH_HIGH_12); *//*0xb0*/
+ /*NO_EMULATE(SEARCH_EQUAL_12); *//*0xb1*/
+ /*NO_EMULATE(SEARCH_LOW_12); *//*0xb2*/
+ NO_EMULATE(READ_ELEMENT_STATUS); /*0xb8*/ /* ch */
+ NO_EMULATE(SEND_VOLUME_TAG); /*0xb6*/ /* ch */
+ /*NO_EMULATE(WRITE_LONG_2); *//*0xea*/
+ NO_EMULATE(READ_16); /*0x88*/ /* sd >2TB */
+ NO_EMULATE(WRITE_16); /*0x8a*/ /* sd >2TB */
+ NO_EMULATE(VERIFY_16); /*0x8f*/
+ NO_EMULATE(SERVICE_ACTION_IN); /*0x9e*/ /* sd >2TB */
+
+/* st: QFA_REQUEST_BLOCK, QFA_SEEK_BLOCK might be needed ? */
+ /*
+ Following commands require emulation.
+ */
+ pre_function[REPORT_LUNS] = __report_luns;
+ bitmap[REPORT_LUNS] = VSCSIIF_NEED_EMULATE_REQBUF |
+ VSCSIIF_NEED_EMULATE_RSPBUF;
+
+ return;
+}
+
+static struct vscsibk_info *vscsibk_info_alloc(domid_t domid)
+{
+ struct vscsibk_info *info;
+
+ info = kmem_cache_zalloc(scsiback_cachep, GFP_KERNEL);
+ if (!info)
+ return ERR_PTR(-ENOMEM);
+
+ info->domid = domid;
+ spin_lock_init(&info->ring_lock);
+ atomic_set(&info->nr_unreplied_reqs, 0);
+ init_waitqueue_head(&info->wq);
+ init_waitqueue_head(&info->shutdown_wq);
+ init_waitqueue_head(&info->waiting_to_free);
+
+ return info;
+}
+
+static void scsiback_notify_work(struct vscsibk_info *info)
+{
+ info->waiting_reqs = 1;
+ wake_up(&info->wq);
+}
+
+static irqreturn_t scsiback_intr(int irq, void *dev_id)
+{
+ scsiback_notify_work((struct vscsibk_info *)dev_id);
+ 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) {
+ pr_err("scsiback: Already connected through?\n");
+ return -1;
+ }
+
+ err = xenbus_map_ring_valloc(info->dev, ring_ref, &area);
+ if (err)
+ return err;
+
+ sring = (struct vscsiif_sring *)area;
+ 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:
+ xenbus_unmap_ring_vfree(info->dev, area);
+
+ return err;
+}
+
+static void scsiback_disconnect(struct vscsibk_info *info)
+{
+ if (info->kthread) {
+ kthread_stop(info->kthread);
+ info->kthread = NULL;
+ wake_up(&info->shutdown_wq);
+ }
+
+ wait_event(info->waiting_to_free,
+ atomic_read(&info->nr_unreplied_reqs) == 0);
+
+ if (info->irq) {
+ unbind_from_irqhandler(info->irq, info);
+ info->irq = 0;
+ }
+
+ if (info->ring.sring) {
+ xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
+ info->ring.sring = NULL;
+ }
+}
+
+static void scsiback_free(struct vscsibk_info *info)
+{
+ kmem_cache_free(scsiback_cachep, info);
+}
+
+static int __init scsiback_interface_init(void)
+{
+ scsiback_cachep = kmem_cache_create("vscsiif_cache",
+ sizeof(struct vscsibk_info), 0, 0, NULL);
+ if (!scsiback_cachep) {
+ pr_err("scsiback: can't init scsi cache\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void scsiback_interface_exit(void)
+{
+ kmem_cache_destroy(scsiback_cachep);
+}
+
+static unsigned int vscsiif_reqs = 128;
+module_param_named(reqs, vscsiif_reqs, uint, 0);
+MODULE_PARM_DESC(reqs, "Number of scsiback requests to allocate");
+
+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 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;
+ struct page **pg;
+ 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) {
+ struct scatterlist *sg;
+
+ /* free of (sgl) in fast_flush_area()*/
+ pending_req->sgl = kmalloc(sizeof(struct scatterlist) *
+ nr_segments, GFP_KERNEL);
+ if (!pending_req->sgl) {
+ pr_err("scsiback: %s: kmalloc() error\n", __FUNCTION__);
+ return -ENOMEM;
+ }
+
+ sg_init_table(pending_req->sgl, nr_segments);
+
+ flags = GNTMAP_host_map;
+ if (write)
+ flags |= GNTMAP_readonly;
+
+ for (i = 0; i < nr_segments; i++)
+ gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
+ ring_req->seg[i].gref, info->domid);
+
+ pg = pending_pages + vaddr_pagenr(pending_req, 0);
+ err = gnttab_map_refs(map, NULL, pg, nr_segments);
+ BUG_ON(err);
+
+ for_each_sg (pending_req->sgl, sg, nr_segments, i) {
+
+ if (unlikely(map[i].status != GNTST_okay)) {
+ pr_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;
+
+ sg_set_page(sg, pg[i], ring_req->seg[i].length,
+ ring_req->seg[i].offset);
+ data_len += sg->length;
+
+ barrier();
+ if (sg->offset >= PAGE_SIZE ||
+ sg->length > PAGE_SIZE ||
+ sg->offset + sg->length > PAGE_SIZE)
+ err |= 1;
+
+ }
+
+ if (err)
+ goto fail_flush;
+ }
+
+ pending_req->request_bufflen = data_len;
+
+ return 0;
+
+fail_flush:
+ scsiback_fast_flush_area(pending_req);
+ return -ENOMEM;
+}
+
+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, 0, pending_req);
+ scsiback_put(info);
+
+ return;
+}
+
+/*
+ Perform virtual to physical translation
+*/
+static 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;
+}
+
+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;
+
+ DPRINTK("%s\n",__FUNCTION__);
+
+ pending_req->rqid = ring_req->rqid;
+ pending_req->act = ring_req->act;
+
+ pending_req->info = info;
+
+ pending_req->v_chn = vir.chn = ring_req->channel;
+ pending_req->v_tgt = vir.tgt = ring_req->id;
+ vir.lun = ring_req->lun;
+
+ rmb();
+ sdev = scsiback_do_translation(info, &vir);
+ if (!sdev) {
+ pending_req->sdev = NULL;
+ DPRINTK("scsiback: doesn't exist.\n");
+ return -ENODEV;
+ }
+ pending_req->sdev = sdev;
+
+ /* request range check from frontend */
+ pending_req->sc_data_direction = ring_req->sc_data_direction;
+ barrier();
+ if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
+ (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
+ (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
+ (pending_req->sc_data_direction != DMA_NONE)) {
+ DPRINTK("scsiback: invalid parameter data_dir = %d\n",
+ pending_req->sc_data_direction);
+ return -EINVAL;
+ }
+
+ pending_req->nr_segments = ring_req->nr_segments;
+ barrier();
+ if (pending_req->nr_segments > VSCSIIF_SG_TABLESIZE) {
+ DPRINTK("scsiback: invalid parameter nr_seg = %d\n",
+ pending_req->nr_segments);
+ return -EINVAL;
+ }
+
+ pending_req->cmd_len = ring_req->cmd_len;
+ barrier();
+ if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
+ DPRINTK("scsiback: invalid parameter cmd_len = %d\n",
+ pending_req->cmd_len);
+ return -EINVAL;
+ }
+ memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
+
+ pending_req->timeout_per_command = ring_req->timeout_per_command;
+
+ if(scsiback_gnttab_data_map(ring_req, pending_req)) {
+ DPRINTK("scsiback: invalid buffer\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+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();
+
+ if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
+ rc = ring->rsp_prod_pvt;
+ pr_warning("scsiback:"
+ " Dom%d provided bogus ring requests (%#x - %#x = %u)."
+ " Halting ring processing\n",
+ info->domid, rp, rc, rp - rc);
+ return -EACCES;
+ }
+
+ 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;
+
+ err = prepare_pending_reqs(info, ring_req,
+ pending_req);
+ switch (err ?: pending_req->act) {
+ case VSCSIIF_ACT_SCSI_CDB:
+ /* The Host mode is through as for Emulation. */
+ if (info->feature == VSCSI_TYPE_HOST)
+ scsiback_cmd_exec(pending_req);
+ else
+ scsiback_req_emulation_or_cmdexec(pending_req);
+ break;
+ case VSCSIIF_ACT_SCSI_RESET:
+ scsiback_device_reset_exec(pending_req);
+ break;
+ default:
+ if(!err && printk_ratelimit())
+ pr_err("scsiback: invalid request\n");
+ scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
+ 0, pending_req);
+ break;
+ case -ENODEV:
+ scsiback_do_resp_with_sense(NULL, DID_NO_CONNECT << 16,
+ 0, pending_req);
+ break;
+ }
+
+ /* Yield point for this unbounded loop. */
+ cond_resched();
+ }
+
+ if (RING_HAS_UNCONSUMED_REQUESTS(ring))
+ more_to_do = 1;
+
+ return more_to_do;
+}
+
+static int scsiback_do_cmd_fn(struct vscsibk_info *info)
+{
+ int more_to_do;
+
+ do {
+ more_to_do = _scsiback_do_cmd_fn(info);
+ if (more_to_do)
+ break;
+
+ RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
+ } while (more_to_do);
+
+ return more_to_do;
+}
+
+static int scsiback_schedule(void *data)
+{
+ struct vscsibk_info *info = (struct vscsibk_info *)data;
+
+ DPRINTK("%s\n",__FUNCTION__);
+
+ 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();
+
+ switch (scsiback_do_cmd_fn(info)) {
+ case 1:
+ info->waiting_reqs = 1;
+ case 0:
+ break;
+ case -EACCES:
+ wait_event_interruptible(info->shutdown_wq,
+ kthread_should_stop());
+ break;
+ default:
+ BUG();
+ }
+ }
+
+ return 0;
+}
+
+static void __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);
+}
+
+static int scsiback_map(struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ unsigned int ring_ref, evtchn;
+ int err;
+ char name[TASK_COMM_LEN];
+
+ 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;
+ }
+
+ err = scsiback_init_sring(be->info, ring_ref, evtchn);
+ if (err)
+ return err;
+
+ __vscsiif_name(be, name);
+
+ 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 (!shost) {
+ pr_err("scsiback: host%d doesn't exist\n", phy->hst);
+ return NULL;
+ }
+ sdev = scsi_device_lookup(shost, phy->chn, phy->tgt, phy->lun);
+ if (!sdev) {
+ pr_err("scsiback: %d:%d:%d:%d doesn't exist\n",
+ phy->hst, phy->chn, phy->tgt, phy->lun);
+ scsi_host_put(shost);
+ return NULL;
+ }
+
+ scsi_host_put(shost);
+ return (sdev);
+}
+
+/*
+ Add a new translation entry
+*/
+static 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)) {
+ pr_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_ATOMIC)) == NULL) {
+ pr_err("scsiback: %s: kmalloc() error\n", __FUNCTION__);
+ err = -ENOMEM;
+ goto out;
+ }
+ new->v = *v;
+ new->sdev = sdev;
+ list_add_tail(&new->l, head);
+
+out:
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+ return err;
+}
+
+/*
+ Delete the translation entry specfied
+*/
+static int scsiback_del_translation_entry(struct vscsibk_info *info,
+ struct ids_tuple *v)
+{
+ struct v2p_entry *entry;
+ struct list_head *head = &(info->v2p_entry_lists);
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->v2p_lock, flags);
+ /* Find out the translation entry specified */
+ list_for_each_entry(entry, head, l) {
+ if ((entry->v.chn == v->chn) &&
+ (entry->v.tgt == v->tgt) &&
+ (entry->v.lun == v->lun)) {
+ goto found;
+ }
+ }
+
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+ return 1;
+
+found:
+ /* Delete the translation entry specfied */
+ scsi_device_put(entry->sdev);
+ list_del(&entry->l);
+ kfree(entry);
+
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+ return 0;
+}
+
+static void scsiback_do_add_lun(struct backend_info *be, const char *state,
+ struct ids_tuple *phy, struct ids_tuple *vir)
+{
+ struct scsi_device *sdev;
+
+ sdev = scsiback_get_scsi_device(phy);
+ if (!sdev) {
+ xenbus_printf(XBT_NIL, be->dev->nodename, state,
+ "%d", XenbusStateClosed);
+ return;
+ }
+ if (!scsiback_add_translation_entry(be->info, sdev, vir)) {
+ if (xenbus_printf(XBT_NIL, be->dev->nodename, state,
+ "%d", XenbusStateInitialised)) {
+ pr_err("scsiback: xenbus_printf error %s\n", state);
+ scsiback_del_translation_entry(be->info, vir);
+ }
+ } else {
+ scsi_device_put(sdev);
+ xenbus_printf(XBT_NIL, be->dev->nodename, state,
+ "%d", XenbusStateClosed);
+ }
+}
+
+static void scsiback_do_del_lun(struct backend_info *be, const char *state,
+ struct ids_tuple *vir)
+{
+ if (!scsiback_del_translation_entry(be->info, vir)) {
+ if (xenbus_printf(XBT_NIL, be->dev->nodename, state,
+ "%d", XenbusStateClosed))
+ pr_err("scsiback: xenbus_printf error %s\n", state);
+ }
+}
+
+#define VSCSIBACK_OP_ADD_OR_DEL_LUN 1
+#define VSCSIBACK_OP_UPDATEDEV_STATE 2
+
+static void scsiback_do_1lun_hotplug(struct backend_info *be, int op, char *ent)
+{
+ int err;
+ struct ids_tuple phy, vir;
+ int device_state;
+ char str[64];
+ char state[64];
+ struct xenbus_device *dev = be->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);
+ err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
+ &phy.hst, &phy.chn, &phy.tgt, &phy.lun);
+ if (XENBUS_EXIST_ERR(err)) {
+ xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed);
+ return;
+ }
+
+ /* 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:
+ if (device_state == XenbusStateInitialising)
+ scsiback_do_add_lun(be, state, &phy, &vir);
+ if (device_state == XenbusStateClosing)
+ scsiback_do_del_lun(be, state, &vir);
+ 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)) {
+ pr_err("scsiback: xenbus_printf error %s\n",
+ str);
+ scsiback_del_translation_entry(be->info, &vir);
+ xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed);
+ }
+ }
+ break;
+ /*When it is necessary, processing is added here.*/
+ default:
+ break;
+ }
+}
+
+static void scsiback_do_lun_hotplug(struct backend_info *be, int op)
+{
+ int i;
+ char **dir;
+ unsigned int ndir = 0;
+
+ dir = xenbus_directory(XBT_NIL, be->dev->nodename, "vscsi-devs", &ndir);
+ if (IS_ERR(dir))
+ return;
+
+ for (i = 0; i < ndir; i++)
+ scsiback_do_1lun_hotplug(be, op, dir[i]);
+
+ kfree(dir);
+ return ;
+}
+
+static void scsiback_frontend_changed(struct xenbus_device *dev,
+ enum xenbus_state frontend_state)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+ 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);
+ xenbus_switch_state(dev, XenbusStateConnected);
+
+ break;
+ case XenbusStateConnected:
+
+ scsiback_do_lun_hotplug(be, VSCSIBACK_OP_UPDATEDEV_STATE);
+
+ if (dev->state == XenbusStateConnected)
+ break;
+
+ xenbus_switch_state(dev, XenbusStateConnected);
+
+ 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;
+ /* fall through if not online */
+ case XenbusStateUnknown:
+ device_unregister(&dev->dev);
+ break;
+
+ case XenbusStateReconfiguring:
+ scsiback_do_lun_hotplug(be, 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) {
+ scsi_device_put(entry->sdev);
+ list_del(&entry->l);
+ kfree(entry);
+ }
+
+ spin_unlock_irqrestore(&info->v2p_lock, flags);
+ return;
+
+}
+
+static int scsiback_remove(struct xenbus_device *dev)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+
+ if (be->info) {
+ scsiback_disconnect(be->info);
+ scsiback_release_translation_entry(be->info);
+ scsiback_free(be->info);
+ be->info = NULL;
+ }
+
+ kfree(be);
+ dev_set_drvdata(&dev->dev, NULL);
+
+ return 0;
+}
+
+/*
+ Initialize the translation entry list
+*/
+static void scsiback_init_translation_table(struct vscsibk_info *info)
+{
+ INIT_LIST_HEAD(&info->v2p_entry_lists);
+ spin_lock_init(&info->v2p_lock);
+}
+
+static int scsiback_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int err;
+ unsigned val = 0;
+
+ 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_set_drvdata(&dev->dev, 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;
+ be->info->feature = 0; /*default not HOSTMODE.*/
+
+ scsiback_init_translation_table(be->info);
+
+ err = xenbus_scanf(XBT_NIL, dev->nodename,
+ "feature-host", "%d", &val);
+ if (XENBUS_EXIST_ERR(err))
+ val = 0;
+
+ if (val)
+ be->info->feature = VSCSI_TYPE_HOST;
+
+ err = xenbus_switch_state(dev, XenbusStateInitWait);
+ if (err)
+ goto fail;
+
+ return 0;
+
+fail:
+ pr_warning("scsiback: %s failed\n",__FUNCTION__);
+ scsiback_remove(dev);
+
+ return err;
+}
+
+static const struct xenbus_device_id scsiback_ids[] = {
+ { "vscsi" },
+ { "" }
+};
+
+static DEFINE_XENBUS_DRIVER(scsiback, ,
+ .probe = scsiback_probe,
+ .remove = scsiback_remove,
+ .otherend_changed = scsiback_frontend_changed
+);
+
+static int __init scsiback_init(void)
+{
+ int i, mmap_pages;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ mmap_pages = vscsiif_reqs * VSCSIIF_SG_TABLESIZE;
+
+ pending_reqs = kzalloc(sizeof(pending_reqs[0]) *
+ vscsiif_reqs, GFP_KERNEL);
+ pending_grant_handles = kmalloc(sizeof(pending_grant_handles[0]) *
+ mmap_pages, GFP_KERNEL);
+ pending_pages = kcalloc(mmap_pages, sizeof(pending_pages[0]),
+ GFP_KERNEL);
+
+ if (!pending_reqs || !pending_grant_handles || !pending_pages)
+ goto out_of_memory;
+
+ if (alloc_xenballooned_pages(mmap_pages, pending_pages, 0))
+ 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;
+
+ INIT_LIST_HEAD(&pending_free);
+
+ for (i = 0; i < vscsiif_reqs; i++)
+ list_add_tail(&pending_reqs[i].free_list, &pending_free);
+
+ if (xenbus_register_backend(&scsiback_driver))
+ goto out_interface;
+
+ scsiback_emulation_init();
+
+ return 0;
+
+out_interface:
+ scsiback_interface_exit();
+out_of_memory:
+ kfree(pending_reqs);
+ kfree(pending_grant_handles);
+ free_xenballooned_pages(mmap_pages, pending_pages);
+ kfree(pending_pages);
+ pr_err("scsiback: %s: out of memory\n", __FUNCTION__);
+ return -ENOMEM;
+}
+
+#if 0
+static void __exit scsiback_exit(void)
+{
+ xenbus_unregister_driver(&scsiback_driver);
+ scsiback_interface_exit();
+ kfree(pending_reqs);
+ kfree(pending_grant_handles);
+ free_xenballooned_pages(vscsiif_reqs * VSCSIIF_SG_TABLESIZE,
+ pending_pages);
+ kfree(pending_pages);
+}
+#endif
+
+module_init(scsiback_init);
+
+#if 0
+module_exit(scsiback_exit);
+#endif
+
+MODULE_DESCRIPTION("Xen SCSI backend driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("xen-backend:vscsi");
--
1.8.4.5