brd: limit 'max_part' module param to DISK_MAX_PARTS

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / target / target_core_iblock.c

/*******************************************************************************
 * Filename:  target_core_iblock.c
 *
 * This file contains the Storage Engine  <-> Linux BlockIO transport
 * specific functions.
 *
 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
 * Copyright (c) 2007-2010 Rising Tide Systems
 * Copyright (c) 2008-2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/version.h>
#include <linux/string.h>
#include <linux/parser.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/smp_lock.h>
#include <linux/bio.h>
#include <linux/genhd.h>
#include <linux/file.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>

#include <target/target_core_base.h>
#include <target/target_core_device.h>
#include <target/target_core_transport.h>

#include "target_core_iblock.h"

#if 0
#define DEBUG_IBLOCK(x...) printk(x)
#else
#define DEBUG_IBLOCK(x...)
#endif

static struct se_subsystem_api iblock_template;

static void iblock_bio_done(struct bio *, int);

/*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
 *
 *
 */
static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
{
        struct iblock_hba *ib_host;

        ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
        if (!(ib_host)) {
                printk(KERN_ERR "Unable to allocate memory for"
                                " struct iblock_hba\n");
                return -ENOMEM;
        }

        ib_host->iblock_host_id = host_id;

        atomic_set(&hba->left_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
        atomic_set(&hba->max_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
        hba->hba_ptr = (void *) ib_host;

        printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
                " Generic Target Core Stack %s\n", hba->hba_id,
                IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);

        printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic"
                " Target Core TCQ Depth: %d\n", hba->hba_id,
                ib_host->iblock_host_id, atomic_read(&hba->max_queue_depth));

        return 0;
}

static void iblock_detach_hba(struct se_hba *hba)
{
        struct iblock_hba *ib_host = hba->hba_ptr;

        printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
                " Target Core\n", hba->hba_id, ib_host->iblock_host_id);

        kfree(ib_host);
        hba->hba_ptr = NULL;
}

static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
{
        struct iblock_dev *ib_dev = NULL;
        struct iblock_hba *ib_host = hba->hba_ptr;

        ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
        if (!(ib_dev)) {
                printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
                return NULL;
        }
        ib_dev->ibd_host = ib_host;

        printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);

        return ib_dev;
}

static struct se_device *iblock_create_virtdevice(
        struct se_hba *hba,
        struct se_subsystem_dev *se_dev,
        void *p)
{
        struct iblock_dev *ib_dev = p;
        struct se_device *dev;
        struct se_dev_limits dev_limits;
        struct block_device *bd = NULL;
        struct request_queue *q;
        struct queue_limits *limits;
        u32 dev_flags = 0;

        if (!(ib_dev)) {
                printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
                return 0;
        }
        memset(&dev_limits, 0, sizeof(struct se_dev_limits));
        /*
         * These settings need to be made tunable..
         */
        ib_dev->ibd_bio_set = bioset_create(32, 64);
        if (!(ib_dev->ibd_bio_set)) {
                printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
                return 0;
        }
        printk(KERN_INFO "IBLOCK: Created bio_set()\n");
        /*
         * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
         * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
         */
        printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
                        ib_dev->ibd_udev_path);

        bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
                                FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
        if (IS_ERR(bd))
                goto failed;
        /*
         * Setup the local scope queue_limits from struct request_queue->limits
         * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
         */
        q = bdev_get_queue(bd);
        limits = &dev_limits.limits;
        limits->logical_block_size = bdev_logical_block_size(bd);
        limits->max_hw_sectors = queue_max_hw_sectors(q);
        limits->max_sectors = queue_max_sectors(q);
        dev_limits.hw_queue_depth = IBLOCK_MAX_DEVICE_QUEUE_DEPTH;
        dev_limits.queue_depth = IBLOCK_DEVICE_QUEUE_DEPTH;

        ib_dev->ibd_major = MAJOR(bd->bd_dev);
        ib_dev->ibd_minor = MINOR(bd->bd_dev);
        ib_dev->ibd_bd = bd;

        dev = transport_add_device_to_core_hba(hba,
                        &iblock_template, se_dev, dev_flags, (void *)ib_dev,
                        &dev_limits, "IBLOCK", IBLOCK_VERSION);
        if (!(dev))
                goto failed;

        ib_dev->ibd_depth = dev->queue_depth;

        /*
         * Check if the underlying struct block_device request_queue supports
         * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
         * in ATA and we need to set TPE=1
         */
        if (blk_queue_discard(bdev_get_queue(bd))) {
                struct request_queue *q = bdev_get_queue(bd);

                DEV_ATTRIB(dev)->max_unmap_lba_count =
                                q->limits.max_discard_sectors;
                /*
                 * Currently hardcoded to 1 in Linux/SCSI code..
                 */
                DEV_ATTRIB(dev)->max_unmap_block_desc_count = 1;
                DEV_ATTRIB(dev)->unmap_granularity =
                                q->limits.discard_granularity;
                DEV_ATTRIB(dev)->unmap_granularity_alignment =
                                q->limits.discard_alignment;

                printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
                                " disabled by default\n");
        }

        return dev;

failed:
        if (ib_dev->ibd_bio_set) {
                bioset_free(ib_dev->ibd_bio_set);
                ib_dev->ibd_bio_set = NULL;
        }
        ib_dev->ibd_bd = NULL;
        ib_dev->ibd_major = 0;
        ib_dev->ibd_minor = 0;
        return NULL;
}

static void iblock_free_device(void *p)
{
        struct iblock_dev *ib_dev = p;

        if (ib_dev->ibd_bd != NULL)
                blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
        if (ib_dev->ibd_bio_set != NULL)
                bioset_free(ib_dev->ibd_bio_set);
        kfree(ib_dev);
}

static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
{
        return container_of(task, struct iblock_req, ib_task);
}

static struct se_task *
iblock_alloc_task(struct se_cmd *cmd)
{
        struct iblock_req *ib_req;

        ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
        if (!(ib_req)) {
                printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
                return NULL;
        }

        ib_req->ib_dev = SE_DEV(cmd)->dev_ptr;
        atomic_set(&ib_req->ib_bio_cnt, 0);
        return &ib_req->ib_task;
}

static unsigned long long iblock_emulate_read_cap_with_block_size(
        struct se_device *dev,
        struct block_device *bd,
        struct request_queue *q)
{
        unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
                                        bdev_logical_block_size(bd)) - 1);
        u32 block_size = bdev_logical_block_size(bd);

        if (block_size == DEV_ATTRIB(dev)->block_size)
                return blocks_long;

        switch (block_size) {
        case 4096:
                switch (DEV_ATTRIB(dev)->block_size) {
                case 2048:
                        blocks_long <<= 1;
                        break;
                case 1024:
                        blocks_long <<= 2;
                        break;
                case 512:
                        blocks_long <<= 3;
                default:
                        break;
                }
                break;
        case 2048:
                switch (DEV_ATTRIB(dev)->block_size) {
                case 4096:
                        blocks_long >>= 1;
                        break;
                case 1024:
                        blocks_long <<= 1;
                        break;
                case 512:
                        blocks_long <<= 2;
                        break;
                default:
                        break;
                }
                break;
        case 1024:
                switch (DEV_ATTRIB(dev)->block_size) {
                case 4096:
                        blocks_long >>= 2;
                        break;
                case 2048:
                        blocks_long >>= 1;
                        break;
                case 512:
                        blocks_long <<= 1;
                        break;
                default:
                        break;
                }
                break;
        case 512:
                switch (DEV_ATTRIB(dev)->block_size) {
                case 4096:
                        blocks_long >>= 3;
                        break;
                case 2048:
                        blocks_long >>= 2;
                        break;
                case 1024:
                        blocks_long >>= 1;
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return blocks_long;
}

/*
 * Emulate SYCHRONIZE_CACHE_*
 */
static void iblock_emulate_sync_cache(struct se_task *task)
{
        struct se_cmd *cmd = TASK_CMD(task);
        struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
        int immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
        sector_t error_sector;
        int ret;

        /*
         * If the Immediate bit is set, queue up the GOOD response
         * for this SYNCHRONIZE_CACHE op
         */
        if (immed)
                transport_complete_sync_cache(cmd, 1);

        /*
         * blkdev_issue_flush() does not support a specifying a range, so
         * we have to flush the entire cache.
         */
        ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
        if (ret != 0) {
                printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
                        " error_sector: %llu\n", ret,
                        (unsigned long long)error_sector);
        }

        if (!immed)
                transport_complete_sync_cache(cmd, ret == 0);
}

/*
 * Tell TCM Core that we are capable of WriteCache emulation for
 * an underlying struct se_device.
 */
static int iblock_emulated_write_cache(struct se_device *dev)
{
        return 1;
}

static int iblock_emulated_dpo(struct se_device *dev)
{
        return 0;
}

/*
 * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
 * for TYPE_DISK.
 */
static int iblock_emulated_fua_write(struct se_device *dev)
{
        return 1;
}

static int iblock_emulated_fua_read(struct se_device *dev)
{
        return 0;
}

static int iblock_do_task(struct se_task *task)
{
        struct se_device *dev = task->task_se_cmd->se_dev;
        struct iblock_req *req = IBLOCK_REQ(task);
        struct iblock_dev *ibd = (struct iblock_dev *)req->ib_dev;
        struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
        struct bio *bio = req->ib_bio, *nbio = NULL;
        int rw;

        if (task->task_data_direction == DMA_TO_DEVICE) {
                /*
                 * Force data to disk if we pretend to not have a volatile
                 * write cache, or the initiator set the Force Unit Access bit.
                 */
                if (DEV_ATTRIB(dev)->emulate_write_cache == 0 ||
                    (DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
                     T_TASK(task->task_se_cmd)->t_tasks_fua))
                        rw = WRITE_FUA;
                else
                        rw = WRITE;
        } else {
                rw = READ;
        }

        while (bio) {
                nbio = bio->bi_next;
                bio->bi_next = NULL;
                DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
                        " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);

                submit_bio(rw, bio);
                bio = nbio;
        }

        if (q->unplug_fn)
                q->unplug_fn(q);
        return PYX_TRANSPORT_SENT_TO_TRANSPORT;
}

static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
{
        struct iblock_dev *ibd = dev->dev_ptr;
        struct block_device *bd = ibd->ibd_bd;
        int barrier = 0;

        return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
}

static void iblock_free_task(struct se_task *task)
{
        struct iblock_req *req = IBLOCK_REQ(task);
        struct bio *bio, *hbio = req->ib_bio;
        /*
         * We only release the bio(s) here if iblock_bio_done() has not called
         * bio_put() -> iblock_bio_destructor().
         */
        while (hbio != NULL) {
                bio = hbio;
                hbio = hbio->bi_next;
                bio->bi_next = NULL;
                bio_put(bio);
        }

        kfree(req);
}

enum {
        Opt_udev_path, Opt_force, Opt_err
};

static match_table_t tokens = {
        {Opt_udev_path, "udev_path=%s"},
        {Opt_force, "force=%d"},
        {Opt_err, NULL}
};

static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
                                               struct se_subsystem_dev *se_dev,
                                               const char *page, ssize_t count)
{
        struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
        char *orig, *ptr, *opts;
        substring_t args[MAX_OPT_ARGS];
        int ret = 0, arg, token;

        opts = kstrdup(page, GFP_KERNEL);
        if (!opts)
                return -ENOMEM;

        orig = opts;

        while ((ptr = strsep(&opts, ",")) != NULL) {
                if (!*ptr)
                        continue;

                token = match_token(ptr, tokens, args);
                switch (token) {
                case Opt_udev_path:
                        if (ib_dev->ibd_bd) {
                                printk(KERN_ERR "Unable to set udev_path= while"
                                        " ib_dev->ibd_bd exists\n");
                                ret = -EEXIST;
                                goto out;
                        }

                        ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
                                "%s", match_strdup(&args[0]));
                        printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
                                        ib_dev->ibd_udev_path);
                        ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
                        break;
                case Opt_force:
                        match_int(args, &arg);
                        ib_dev->ibd_force = arg;
                        printk(KERN_INFO "IBLOCK: Set force=%d\n",
                                ib_dev->ibd_force);
                        break;
                default:
                        break;
                }
        }

out:
        kfree(orig);
        return (!ret) ? count : ret;
}

static ssize_t iblock_check_configfs_dev_params(
        struct se_hba *hba,
        struct se_subsystem_dev *se_dev)
{
        struct iblock_dev *ibd = se_dev->se_dev_su_ptr;

        if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
                printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
                return -1;
        }

        return 0;
}

static ssize_t iblock_show_configfs_dev_params(
        struct se_hba *hba,
        struct se_subsystem_dev *se_dev,
        char *b)
{
        struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
        struct block_device *bd = ibd->ibd_bd;
        char buf[BDEVNAME_SIZE];
        ssize_t bl = 0;

        if (bd)
                bl += sprintf(b + bl, "iBlock device: %s",
                                bdevname(bd, buf));
        if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
                bl += sprintf(b + bl, "  UDEV PATH: %s\n",
                                ibd->ibd_udev_path);
        } else
                bl += sprintf(b + bl, "\n");

        bl += sprintf(b + bl, "        ");
        if (bd) {
                bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
                        ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
                        "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
                        "CLAIMED: IBLOCK" : "CLAIMED: OS");
        } else {
                bl += sprintf(b + bl, "Major: %d Minor: %d\n",
                        ibd->ibd_major, ibd->ibd_minor);
        }

        return bl;
}

static void iblock_bio_destructor(struct bio *bio)
{
        struct se_task *task = bio->bi_private;
        struct iblock_dev *ib_dev = task->se_dev->dev_ptr;

        bio_free(bio, ib_dev->ibd_bio_set);
}

static struct bio *iblock_get_bio(
        struct se_task *task,
        struct iblock_req *ib_req,
        struct iblock_dev *ib_dev,
        int *ret,
        sector_t lba,
        u32 sg_num)
{
        struct bio *bio;

        bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
        if (!(bio)) {
                printk(KERN_ERR "Unable to allocate memory for bio\n");
                *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
                return NULL;
        }

        DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
                " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
        DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);

        bio->bi_bdev = ib_dev->ibd_bd;
        bio->bi_private = (void *) task;
        bio->bi_destructor = iblock_bio_destructor;
        bio->bi_end_io = &iblock_bio_done;
        bio->bi_sector = lba;
        atomic_inc(&ib_req->ib_bio_cnt);

        DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
        DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
                        atomic_read(&ib_req->ib_bio_cnt));
        return bio;
}

static int iblock_map_task_SG(struct se_task *task)
{
        struct se_cmd *cmd = task->task_se_cmd;
        struct se_device *dev = SE_DEV(cmd);
        struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
        struct iblock_req *ib_req = IBLOCK_REQ(task);
        struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
        struct scatterlist *sg;
        int ret = 0;
        u32 i, sg_num = task->task_sg_num;
        sector_t block_lba;
        /*
         * Do starting conversion up from non 512-byte blocksize with
         * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
         */
        if (DEV_ATTRIB(dev)->block_size == 4096)
                block_lba = (task->task_lba << 3);
        else if (DEV_ATTRIB(dev)->block_size == 2048)
                block_lba = (task->task_lba << 2);
        else if (DEV_ATTRIB(dev)->block_size == 1024)
                block_lba = (task->task_lba << 1);
        else if (DEV_ATTRIB(dev)->block_size == 512)
                block_lba = task->task_lba;
        else {
                printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
                                " %u\n", DEV_ATTRIB(dev)->block_size);
                return PYX_TRANSPORT_LU_COMM_FAILURE;
        }

        bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
        if (!(bio))
                return ret;

        ib_req->ib_bio = bio;
        hbio = tbio = bio;
        /*
         * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
         * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
         */
        for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
                DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
                        " %p len: %u offset: %u\n", task, bio, sg_page(sg),
                                sg->length, sg->offset);
again:
                ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
                if (ret != sg->length) {

                        DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
                                        bio->bi_sector);
                        DEBUG_IBLOCK("** task->task_size: %u\n",
                                        task->task_size);
                        DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
                                        bio->bi_max_vecs);
                        DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
                                        bio->bi_vcnt);

                        bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
                                                block_lba, sg_num);
                        if (!(bio))
                                goto fail;

                        tbio = tbio->bi_next = bio;
                        DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
                                " list, Going to again\n", bio);
                        goto again;
                }
                /* Always in 512 byte units for Linux/Block */
                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
                sg_num--;
                DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
                        " sg_num to %u\n", task, sg_num);
                DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
                                " to %llu\n", task, block_lba);
                DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
                                " %u\n", task, bio->bi_vcnt);
        }

        return 0;
fail:
        while (hbio) {
                bio = hbio;
                hbio = hbio->bi_next;
                bio->bi_next = NULL;
                bio_put(bio);
        }
        return ret;
}

static unsigned char *iblock_get_cdb(struct se_task *task)
{
        return IBLOCK_REQ(task)->ib_scsi_cdb;
}

static u32 iblock_get_device_rev(struct se_device *dev)
{
        return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
}

static u32 iblock_get_device_type(struct se_device *dev)
{
        return TYPE_DISK;
}

static sector_t iblock_get_blocks(struct se_device *dev)
{
        struct iblock_dev *ibd = dev->dev_ptr;
        struct block_device *bd = ibd->ibd_bd;
        struct request_queue *q = bdev_get_queue(bd);

        return iblock_emulate_read_cap_with_block_size(dev, bd, q);
}

static void iblock_bio_done(struct bio *bio, int err)
{
        struct se_task *task = bio->bi_private;
        struct iblock_req *ibr = IBLOCK_REQ(task);
        /*
         * Set -EIO if !BIO_UPTODATE and the passed is still err=0
         */
        if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
                err = -EIO;

        if (err != 0) {
                printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
                        " err: %d\n", bio, err);
                /*
                 * Bump the ib_bio_err_cnt and release bio.
                 */
                atomic_inc(&ibr->ib_bio_err_cnt);
                smp_mb__after_atomic_inc();
                bio_put(bio);
                /*
                 * Wait to complete the task until the last bio as completed.
                 */
                if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
                        return;

                ibr->ib_bio = NULL;
                transport_complete_task(task, 0);
                return;
        }
        DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
                task, bio, task->task_lba, bio->bi_sector, err);
        /*
         * bio_put() will call iblock_bio_destructor() to release the bio back
         * to ibr->ib_bio_set.
         */
        bio_put(bio);
        /*
         * Wait to complete the task until the last bio as completed.
         */
        if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
                return;
        /*
         * Return GOOD status for task if zero ib_bio_err_cnt exists.
         */
        ibr->ib_bio = NULL;
        transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
}

static struct se_subsystem_api iblock_template = {
        .name                   = "iblock",
        .owner                  = THIS_MODULE,
        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
        .map_task_SG            = iblock_map_task_SG,
        .attach_hba             = iblock_attach_hba,
        .detach_hba             = iblock_detach_hba,
        .allocate_virtdevice    = iblock_allocate_virtdevice,
        .create_virtdevice      = iblock_create_virtdevice,
        .free_device            = iblock_free_device,
        .dpo_emulated           = iblock_emulated_dpo,
        .fua_write_emulated     = iblock_emulated_fua_write,
        .fua_read_emulated      = iblock_emulated_fua_read,
        .write_cache_emulated   = iblock_emulated_write_cache,
        .alloc_task             = iblock_alloc_task,
        .do_task                = iblock_do_task,
        .do_discard             = iblock_do_discard,
        .do_sync_cache          = iblock_emulate_sync_cache,
        .free_task              = iblock_free_task,
        .check_configfs_dev_params = iblock_check_configfs_dev_params,
        .set_configfs_dev_params = iblock_set_configfs_dev_params,
        .show_configfs_dev_params = iblock_show_configfs_dev_params,
        .get_cdb                = iblock_get_cdb,
        .get_device_rev         = iblock_get_device_rev,
        .get_device_type        = iblock_get_device_type,
        .get_blocks             = iblock_get_blocks,
};

static int __init iblock_module_init(void)
{
        return transport_subsystem_register(&iblock_template);
}

static void iblock_module_exit(void)
{
        transport_subsystem_release(&iblock_template);
}

MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
MODULE_AUTHOR("nab@Linux-iSCSI.org");
MODULE_LICENSE("GPL");

module_init(iblock_module_init);
module_exit(iblock_module_exit);