vmw_pvscsi.c

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/*
 * Linux driver for VMware's para-virtualized SCSI HBA.
 *
 * Copyright (C) 2008-2009, VMware, Inc. All Rights Reserved.
 *
 * 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; version 2 of the License and no 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, GOOD TITLE or
 * NON INFRINGEMENT.  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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Maintained by: Arvind Kumar <[email protected]>
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/pci.h>

#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>

#include "vmw_pvscsi.h"

#define PVSCSI_LINUX_DRIVER_DESC "VMware PVSCSI driver"

MODULE_DESCRIPTION(PVSCSI_LINUX_DRIVER_DESC);
MODULE_AUTHOR("VMware, Inc.");
MODULE_LICENSE("GPL");
MODULE_VERSION(PVSCSI_DRIVER_VERSION_STRING);

#define PVSCSI_DEFAULT_NUM_PAGES_PER_RING   8
#define PVSCSI_DEFAULT_NUM_PAGES_MSG_RING   1
#define PVSCSI_DEFAULT_QUEUE_DEPTH      64
#define SGL_SIZE                PAGE_SIZE

struct pvscsi_sg_list {
    struct PVSCSISGElement sge[PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT];
};

struct pvscsi_ctx {
    /*
     * The index of the context in cmd_map serves as the context ID for a
     * 1-to-1 mapping completions back to requests.
     */
    struct scsi_cmnd    *cmd;
    struct pvscsi_sg_list   *sgl;
    struct list_head    list;
    dma_addr_t      dataPA;
    dma_addr_t      sensePA;
    dma_addr_t      sglPA;
};

struct pvscsi_adapter {
    char                *mmioBase;
    unsigned int            irq;
    u8              rev;
    bool                use_msi;
    bool                use_msix;
    bool                use_msg;

    spinlock_t          hw_lock;

    struct workqueue_struct     *workqueue;
    struct work_struct      work;

    struct PVSCSIRingReqDesc    *req_ring;
    unsigned            req_pages;
    unsigned            req_depth;
    dma_addr_t          reqRingPA;

    struct PVSCSIRingCmpDesc    *cmp_ring;
    unsigned            cmp_pages;
    dma_addr_t          cmpRingPA;

    struct PVSCSIRingMsgDesc    *msg_ring;
    unsigned            msg_pages;
    dma_addr_t          msgRingPA;

    struct PVSCSIRingsState     *rings_state;
    dma_addr_t          ringStatePA;

    struct pci_dev          *dev;
    struct Scsi_Host        *host;

    struct list_head        cmd_pool;
    struct pvscsi_ctx       *cmd_map;
};


/* Command line parameters */
static int pvscsi_ring_pages     = PVSCSI_DEFAULT_NUM_PAGES_PER_RING;
static int pvscsi_msg_ring_pages = PVSCSI_DEFAULT_NUM_PAGES_MSG_RING;
static int pvscsi_cmd_per_lun    = PVSCSI_DEFAULT_QUEUE_DEPTH;
static bool pvscsi_disable_msi;
static bool pvscsi_disable_msix;
static bool pvscsi_use_msg       = true;

#define PVSCSI_RW (S_IRUSR | S_IWUSR)

module_param_named(ring_pages, pvscsi_ring_pages, int, PVSCSI_RW);
MODULE_PARM_DESC(ring_pages, "Number of pages per req/cmp ring - (default="
         __stringify(PVSCSI_DEFAULT_NUM_PAGES_PER_RING) ")");

module_param_named(msg_ring_pages, pvscsi_msg_ring_pages, int, PVSCSI_RW);
MODULE_PARM_DESC(msg_ring_pages, "Number of pages for the msg ring - (default="
         __stringify(PVSCSI_DEFAULT_NUM_PAGES_MSG_RING) ")");

module_param_named(cmd_per_lun, pvscsi_cmd_per_lun, int, PVSCSI_RW);
MODULE_PARM_DESC(cmd_per_lun, "Maximum commands per lun - (default="
         __stringify(PVSCSI_MAX_REQ_QUEUE_DEPTH) ")");

module_param_named(disable_msi, pvscsi_disable_msi, bool, PVSCSI_RW);
MODULE_PARM_DESC(disable_msi, "Disable MSI use in driver - (default=0)");

module_param_named(disable_msix, pvscsi_disable_msix, bool, PVSCSI_RW);
MODULE_PARM_DESC(disable_msix, "Disable MSI-X use in driver - (default=0)");

module_param_named(use_msg, pvscsi_use_msg, bool, PVSCSI_RW);
MODULE_PARM_DESC(use_msg, "Use msg ring when available - (default=1)");

static const struct pci_device_id pvscsi_pci_tbl[] = {
    { PCI_VDEVICE(VMWARE, PCI_DEVICE_ID_VMWARE_PVSCSI) },
    { 0 }
};

MODULE_DEVICE_TABLE(pci, pvscsi_pci_tbl);

static struct device *
pvscsi_dev(const struct pvscsi_adapter *adapter)
{
    return &(adapter->dev->dev);
}

static struct pvscsi_ctx *
pvscsi_find_context(const struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
{
    struct pvscsi_ctx *ctx, *end;

    end = &adapter->cmd_map[adapter->req_depth];
    for (ctx = adapter->cmd_map; ctx < end; ctx++)
        if (ctx->cmd == cmd)
            return ctx;

    return NULL;
}

static struct pvscsi_ctx *
pvscsi_acquire_context(struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
{
    struct pvscsi_ctx *ctx;

    if (list_empty(&adapter->cmd_pool))
        return NULL;

    ctx = list_first_entry(&adapter->cmd_pool, struct pvscsi_ctx, list);
    ctx->cmd = cmd;
    list_del(&ctx->list);

    return ctx;
}

static void pvscsi_release_context(struct pvscsi_adapter *adapter,
                   struct pvscsi_ctx *ctx)
{
    ctx->cmd = NULL;
    list_add(&ctx->list, &adapter->cmd_pool);
}

/*
 * Map a pvscsi_ctx struct to a context ID field value; we map to a simple
 * non-zero integer. ctx always points to an entry in cmd_map array, hence
 * the return value is always >=1.
 */
static u64 pvscsi_map_context(const struct pvscsi_adapter *adapter,
                  const struct pvscsi_ctx *ctx)
{
    return ctx - adapter->cmd_map + 1;
}

static struct pvscsi_ctx *
pvscsi_get_context(const struct pvscsi_adapter *adapter, u64 context)
{
    return &adapter->cmd_map[context - 1];
}

static void pvscsi_reg_write(const struct pvscsi_adapter *adapter,
                 u32 offset, u32 val)
{
    writel(val, adapter->mmioBase + offset);
}

static u32 pvscsi_reg_read(const struct pvscsi_adapter *adapter, u32 offset)
{
    return readl(adapter->mmioBase + offset);
}

static u32 pvscsi_read_intr_status(const struct pvscsi_adapter *adapter)
{
    return pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_INTR_STATUS);
}

static void pvscsi_write_intr_status(const struct pvscsi_adapter *adapter,
                     u32 val)
{
    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_STATUS, val);
}

static void pvscsi_unmask_intr(const struct pvscsi_adapter *adapter)
{
    u32 intr_bits;

    intr_bits = PVSCSI_INTR_CMPL_MASK;
    if (adapter->use_msg)
        intr_bits |= PVSCSI_INTR_MSG_MASK;

    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, intr_bits);
}

static void pvscsi_mask_intr(const struct pvscsi_adapter *adapter)
{
    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, 0);
}

static void pvscsi_write_cmd_desc(const struct pvscsi_adapter *adapter,
                  u32 cmd, const void *desc, size_t len)
{
    const u32 *ptr = desc;
    size_t i;

    len /= sizeof(*ptr);
    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND, cmd);
    for (i = 0; i < len; i++)
        pvscsi_reg_write(adapter,
                 PVSCSI_REG_OFFSET_COMMAND_DATA, ptr[i]);
}

static void pvscsi_abort_cmd(const struct pvscsi_adapter *adapter,
                 const struct pvscsi_ctx *ctx)
{
    struct PVSCSICmdDescAbortCmd cmd = { 0 };

    cmd.target = ctx->cmd->device->id;
    cmd.context = pvscsi_map_context(adapter, ctx);

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ABORT_CMD, &cmd, sizeof(cmd));
}

static void pvscsi_kick_rw_io(const struct pvscsi_adapter *adapter)
{
    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_RW_IO, 0);
}

static void pvscsi_process_request_ring(const struct pvscsi_adapter *adapter)
{
    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_NON_RW_IO, 0);
}

static int scsi_is_rw(unsigned char op)
{
    return op == READ_6  || op == WRITE_6 ||
           op == READ_10 || op == WRITE_10 ||
           op == READ_12 || op == WRITE_12 ||
           op == READ_16 || op == WRITE_16;
}

static void pvscsi_kick_io(const struct pvscsi_adapter *adapter,
               unsigned char op)
{
    if (scsi_is_rw(op))
        pvscsi_kick_rw_io(adapter);
    else
        pvscsi_process_request_ring(adapter);
}

static void ll_adapter_reset(const struct pvscsi_adapter *adapter)
{
    dev_dbg(pvscsi_dev(adapter), "Adapter Reset on %p\n", adapter);

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ADAPTER_RESET, NULL, 0);
}

static void ll_bus_reset(const struct pvscsi_adapter *adapter)
{
    dev_dbg(pvscsi_dev(adapter), "Resetting bus on %p\n", adapter);

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_BUS, NULL, 0);
}

static void ll_device_reset(const struct pvscsi_adapter *adapter, u32 target)
{
    struct PVSCSICmdDescResetDevice cmd = { 0 };

    dev_dbg(pvscsi_dev(adapter), "Resetting device: target=%u\n", target);

    cmd.target = target;

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_DEVICE,
                  &cmd, sizeof(cmd));
}

static void pvscsi_create_sg(struct pvscsi_ctx *ctx,
                 struct scatterlist *sg, unsigned count)
{
    unsigned i;
    struct PVSCSISGElement *sge;

    BUG_ON(count > PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT);

    sge = &ctx->sgl->sge[0];
    for (i = 0; i < count; i++, sg++) {
        sge[i].addr   = sg_dma_address(sg);
        sge[i].length = sg_dma_len(sg);
        sge[i].flags  = 0;
    }
}

/*
 * Map all data buffers for a command into PCI space and
 * setup the scatter/gather list if needed.
 */
static void pvscsi_map_buffers(struct pvscsi_adapter *adapter,
                   struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd,
                   struct PVSCSIRingReqDesc *e)
{
    unsigned count;
    unsigned bufflen = scsi_bufflen(cmd);
    struct scatterlist *sg;

    e->dataLen = bufflen;
    e->dataAddr = 0;
    if (bufflen == 0)
        return;

    sg = scsi_sglist(cmd);
    count = scsi_sg_count(cmd);
    if (count != 0) {
        int segs = scsi_dma_map(cmd);
        if (segs > 1) {
            pvscsi_create_sg(ctx, sg, segs);

            e->flags |= PVSCSI_FLAG_CMD_WITH_SG_LIST;
            ctx->sglPA = pci_map_single(adapter->dev, ctx->sgl,
                            SGL_SIZE, PCI_DMA_TODEVICE);
            e->dataAddr = ctx->sglPA;
        } else
            e->dataAddr = sg_dma_address(sg);
    } else {
        /*
         * In case there is no S/G list, scsi_sglist points
         * directly to the buffer.
         */
        ctx->dataPA = pci_map_single(adapter->dev, sg, bufflen,
                         cmd->sc_data_direction);
        e->dataAddr = ctx->dataPA;
    }
}

static void pvscsi_unmap_buffers(const struct pvscsi_adapter *adapter,
                 struct pvscsi_ctx *ctx)
{
    struct scsi_cmnd *cmd;
    unsigned bufflen;

    cmd = ctx->cmd;
    bufflen = scsi_bufflen(cmd);

    if (bufflen != 0) {
        unsigned count = scsi_sg_count(cmd);

        if (count != 0) {
            scsi_dma_unmap(cmd);
            if (ctx->sglPA) {
                pci_unmap_single(adapter->dev, ctx->sglPA,
                         SGL_SIZE, PCI_DMA_TODEVICE);
                ctx->sglPA = 0;
            }
        } else
            pci_unmap_single(adapter->dev, ctx->dataPA, bufflen,
                     cmd->sc_data_direction);
    }
    if (cmd->sense_buffer)
        pci_unmap_single(adapter->dev, ctx->sensePA,
                 SCSI_SENSE_BUFFERSIZE, PCI_DMA_FROMDEVICE);
}

static int __devinit pvscsi_allocate_rings(struct pvscsi_adapter *adapter)
{
    adapter->rings_state = pci_alloc_consistent(adapter->dev, PAGE_SIZE,
                            &adapter->ringStatePA);
    if (!adapter->rings_state)
        return -ENOMEM;

    adapter->req_pages = min(PVSCSI_MAX_NUM_PAGES_REQ_RING,
                 pvscsi_ring_pages);
    adapter->req_depth = adapter->req_pages
                    * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
    adapter->req_ring = pci_alloc_consistent(adapter->dev,
                         adapter->req_pages * PAGE_SIZE,
                         &adapter->reqRingPA);
    if (!adapter->req_ring)
        return -ENOMEM;

    adapter->cmp_pages = min(PVSCSI_MAX_NUM_PAGES_CMP_RING,
                 pvscsi_ring_pages);
    adapter->cmp_ring = pci_alloc_consistent(adapter->dev,
                         adapter->cmp_pages * PAGE_SIZE,
                         &adapter->cmpRingPA);
    if (!adapter->cmp_ring)
        return -ENOMEM;

    BUG_ON(!IS_ALIGNED(adapter->ringStatePA, PAGE_SIZE));
    BUG_ON(!IS_ALIGNED(adapter->reqRingPA, PAGE_SIZE));
    BUG_ON(!IS_ALIGNED(adapter->cmpRingPA, PAGE_SIZE));

    if (!adapter->use_msg)
        return 0;

    adapter->msg_pages = min(PVSCSI_MAX_NUM_PAGES_MSG_RING,
                 pvscsi_msg_ring_pages);
    adapter->msg_ring = pci_alloc_consistent(adapter->dev,
                         adapter->msg_pages * PAGE_SIZE,
                         &adapter->msgRingPA);
    if (!adapter->msg_ring)
        return -ENOMEM;
    BUG_ON(!IS_ALIGNED(adapter->msgRingPA, PAGE_SIZE));

    return 0;
}

static void pvscsi_setup_all_rings(const struct pvscsi_adapter *adapter)
{
    struct PVSCSICmdDescSetupRings cmd = { 0 };
    dma_addr_t base;
    unsigned i;

    cmd.ringsStatePPN   = adapter->ringStatePA >> PAGE_SHIFT;
    cmd.reqRingNumPages = adapter->req_pages;
    cmd.cmpRingNumPages = adapter->cmp_pages;

    base = adapter->reqRingPA;
    for (i = 0; i < adapter->req_pages; i++) {
        cmd.reqRingPPNs[i] = base >> PAGE_SHIFT;
        base += PAGE_SIZE;
    }

    base = adapter->cmpRingPA;
    for (i = 0; i < adapter->cmp_pages; i++) {
        cmd.cmpRingPPNs[i] = base >> PAGE_SHIFT;
        base += PAGE_SIZE;
    }

    memset(adapter->rings_state, 0, PAGE_SIZE);
    memset(adapter->req_ring, 0, adapter->req_pages * PAGE_SIZE);
    memset(adapter->cmp_ring, 0, adapter->cmp_pages * PAGE_SIZE);

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_RINGS,
                  &cmd, sizeof(cmd));

    if (adapter->use_msg) {
        struct PVSCSICmdDescSetupMsgRing cmd_msg = { 0 };

        cmd_msg.numPages = adapter->msg_pages;

        base = adapter->msgRingPA;
        for (i = 0; i < adapter->msg_pages; i++) {
            cmd_msg.ringPPNs[i] = base >> PAGE_SHIFT;
            base += PAGE_SIZE;
        }
        memset(adapter->msg_ring, 0, adapter->msg_pages * PAGE_SIZE);

        pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_MSG_RING,
                      &cmd_msg, sizeof(cmd_msg));
    }
}

/*
 * Pull a completion descriptor off and pass the completion back
 * to the SCSI mid layer.
 */
static void pvscsi_complete_request(struct pvscsi_adapter *adapter,
                    const struct PVSCSIRingCmpDesc *e)
{
    struct pvscsi_ctx *ctx;
    struct scsi_cmnd *cmd;
    u32 btstat = e->hostStatus;
    u32 sdstat = e->scsiStatus;

    ctx = pvscsi_get_context(adapter, e->context);
    cmd = ctx->cmd;
    pvscsi_unmap_buffers(adapter, ctx);
    pvscsi_release_context(adapter, ctx);
    cmd->result = 0;

    if (sdstat != SAM_STAT_GOOD &&
        (btstat == BTSTAT_SUCCESS ||
         btstat == BTSTAT_LINKED_COMMAND_COMPLETED ||
         btstat == BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG)) {
        cmd->result = (DID_OK << 16) | sdstat;
        if (sdstat == SAM_STAT_CHECK_CONDITION && cmd->sense_buffer)
            cmd->result |= (DRIVER_SENSE << 24);
    } else
        switch (btstat) {
        case BTSTAT_SUCCESS:
        case BTSTAT_LINKED_COMMAND_COMPLETED:
        case BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG:
            /* If everything went fine, let's move on..  */
            cmd->result = (DID_OK << 16);
            break;

        case BTSTAT_DATARUN:
        case BTSTAT_DATA_UNDERRUN:
            /* Report residual data in underruns */
            scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen);
            cmd->result = (DID_ERROR << 16);
            break;

        case BTSTAT_SELTIMEO:
            /* Our emulation returns this for non-connected devs */
            cmd->result = (DID_BAD_TARGET << 16);
            break;

        case BTSTAT_LUNMISMATCH:
        case BTSTAT_TAGREJECT:
        case BTSTAT_BADMSG:
            cmd->result = (DRIVER_INVALID << 24);
            /* fall through */

        case BTSTAT_HAHARDWARE:
        case BTSTAT_INVPHASE:
        case BTSTAT_HATIMEOUT:
        case BTSTAT_NORESPONSE:
        case BTSTAT_DISCONNECT:
        case BTSTAT_HASOFTWARE:
        case BTSTAT_BUSFREE:
        case BTSTAT_SENSFAILED:
            cmd->result |= (DID_ERROR << 16);
            break;

        case BTSTAT_SENTRST:
        case BTSTAT_RECVRST:
        case BTSTAT_BUSRESET:
            cmd->result = (DID_RESET << 16);
            break;

        case BTSTAT_ABORTQUEUE:
            cmd->result = (DID_ABORT << 16);
            break;

        case BTSTAT_SCSIPARITY:
            cmd->result = (DID_PARITY << 16);
            break;

        default:
            cmd->result = (DID_ERROR << 16);
            scmd_printk(KERN_DEBUG, cmd,
                    "Unknown completion status: 0x%x\n",
                    btstat);
    }

    dev_dbg(&cmd->device->sdev_gendev,
        "cmd=%p %x ctx=%p result=0x%x status=0x%x,%x\n",
        cmd, cmd->cmnd[0], ctx, cmd->result, btstat, sdstat);

    cmd->scsi_done(cmd);
}

/*
 * barrier usage : Since the PVSCSI device is emulated, there could be cases
 * where we may want to serialize some accesses between the driver and the
 * emulation layer. We use compiler barriers instead of the more expensive
 * memory barriers because PVSCSI is only supported on X86 which has strong
 * memory access ordering.
 */
static void pvscsi_process_completion_ring(struct pvscsi_adapter *adapter)
{
    struct PVSCSIRingsState *s = adapter->rings_state;
    struct PVSCSIRingCmpDesc *ring = adapter->cmp_ring;
    u32 cmp_entries = s->cmpNumEntriesLog2;

    while (s->cmpConsIdx != s->cmpProdIdx) {
        struct PVSCSIRingCmpDesc *e = ring + (s->cmpConsIdx &
                              MASK(cmp_entries));
        /*
         * This barrier() ensures that *e is not dereferenced while
         * the device emulation still writes data into the slot.
         * Since the device emulation advances s->cmpProdIdx only after
         * updating the slot we want to check it first.
         */
        barrier();
        pvscsi_complete_request(adapter, e);
        /*
         * This barrier() ensures that compiler doesn't reorder write
         * to s->cmpConsIdx before the read of (*e) inside
         * pvscsi_complete_request. Otherwise, device emulation may
         * overwrite *e before we had a chance to read it.
         */
        barrier();
        s->cmpConsIdx++;
    }
}

/*
 * Translate a Linux SCSI request into a request ring entry.
 */
static int pvscsi_queue_ring(struct pvscsi_adapter *adapter,
                 struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd)
{
    struct PVSCSIRingsState *s;
    struct PVSCSIRingReqDesc *e;
    struct scsi_device *sdev;
    u32 req_entries;

    s = adapter->rings_state;
    sdev = cmd->device;
    req_entries = s->reqNumEntriesLog2;

    /*
     * If this condition holds, we might have room on the request ring, but
     * we might not have room on the completion ring for the response.
     * However, we have already ruled out this possibility - we would not
     * have successfully allocated a context if it were true, since we only
     * have one context per request entry.  Check for it anyway, since it
     * would be a serious bug.
     */
    if (s->reqProdIdx - s->cmpConsIdx >= 1 << req_entries) {
        scmd_printk(KERN_ERR, cmd, "vmw_pvscsi: "
                "ring full: reqProdIdx=%d cmpConsIdx=%d\n",
                s->reqProdIdx, s->cmpConsIdx);
        return -1;
    }

    e = adapter->req_ring + (s->reqProdIdx & MASK(req_entries));

    e->bus    = sdev->channel;
    e->target = sdev->id;
    memset(e->lun, 0, sizeof(e->lun));
    e->lun[1] = sdev->lun;

    if (cmd->sense_buffer) {
        ctx->sensePA = pci_map_single(adapter->dev, cmd->sense_buffer,
                          SCSI_SENSE_BUFFERSIZE,
                          PCI_DMA_FROMDEVICE);
        e->senseAddr = ctx->sensePA;
        e->senseLen = SCSI_SENSE_BUFFERSIZE;
    } else {
        e->senseLen  = 0;
        e->senseAddr = 0;
    }
    e->cdbLen   = cmd->cmd_len;
    e->vcpuHint = smp_processor_id();
    memcpy(e->cdb, cmd->cmnd, e->cdbLen);

    e->tag = SIMPLE_QUEUE_TAG;
    if (sdev->tagged_supported &&
        (cmd->tag == HEAD_OF_QUEUE_TAG ||
         cmd->tag == ORDERED_QUEUE_TAG))
        e->tag = cmd->tag;

    if (cmd->sc_data_direction == DMA_FROM_DEVICE)
        e->flags = PVSCSI_FLAG_CMD_DIR_TOHOST;
    else if (cmd->sc_data_direction == DMA_TO_DEVICE)
        e->flags = PVSCSI_FLAG_CMD_DIR_TODEVICE;
    else if (cmd->sc_data_direction == DMA_NONE)
        e->flags = PVSCSI_FLAG_CMD_DIR_NONE;
    else
        e->flags = 0;

    pvscsi_map_buffers(adapter, ctx, cmd, e);

    e->context = pvscsi_map_context(adapter, ctx);

    barrier();

    s->reqProdIdx++;

    return 0;
}

static int pvscsi_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
    struct Scsi_Host *host = cmd->device->host;
    struct pvscsi_adapter *adapter = shost_priv(host);
    struct pvscsi_ctx *ctx;
    unsigned long flags;

    spin_lock_irqsave(&adapter->hw_lock, flags);

    ctx = pvscsi_acquire_context(adapter, cmd);
    if (!ctx || pvscsi_queue_ring(adapter, ctx, cmd) != 0) {
        if (ctx)
            pvscsi_release_context(adapter, ctx);
        spin_unlock_irqrestore(&adapter->hw_lock, flags);
        return SCSI_MLQUEUE_HOST_BUSY;
    }

    cmd->scsi_done = done;

    dev_dbg(&cmd->device->sdev_gendev,
        "queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]);

    spin_unlock_irqrestore(&adapter->hw_lock, flags);

    pvscsi_kick_io(adapter, cmd->cmnd[0]);

    return 0;
}

static DEF_SCSI_QCMD(pvscsi_queue)

static int pvscsi_abort(struct scsi_cmnd *cmd)
{
    struct pvscsi_adapter *adapter = shost_priv(cmd->device->host);
    struct pvscsi_ctx *ctx;
    unsigned long flags;

    scmd_printk(KERN_DEBUG, cmd, "task abort on host %u, %p\n",
            adapter->host->host_no, cmd);

    spin_lock_irqsave(&adapter->hw_lock, flags);

    /*
     * Poll the completion ring first - we might be trying to abort
     * a command that is waiting to be dispatched in the completion ring.
     */
    pvscsi_process_completion_ring(adapter);

    /*
     * If there is no context for the command, it either already succeeded
     * or else was never properly issued.  Not our problem.
     */
    ctx = pvscsi_find_context(adapter, cmd);
    if (!ctx) {
        scmd_printk(KERN_DEBUG, cmd, "Failed to abort cmd %p\n", cmd);
        goto out;
    }

    pvscsi_abort_cmd(adapter, ctx);

    pvscsi_process_completion_ring(adapter);

out:
    spin_unlock_irqrestore(&adapter->hw_lock, flags);
    return SUCCESS;
}

/*
 * Abort all outstanding requests.  This is only safe to use if the completion
 * ring will never be walked again or the device has been reset, because it
 * destroys the 1-1 mapping between context field passed to emulation and our
 * request structure.
 */
static void pvscsi_reset_all(struct pvscsi_adapter *adapter)
{
    unsigned i;

    for (i = 0; i < adapter->req_depth; i++) {
        struct pvscsi_ctx *ctx = &adapter->cmd_map[i];
        struct scsi_cmnd *cmd = ctx->cmd;
        if (cmd) {
            scmd_printk(KERN_ERR, cmd,
                    "Forced reset on cmd %p\n", cmd);
            pvscsi_unmap_buffers(adapter, ctx);
            pvscsi_release_context(adapter, ctx);
            cmd->result = (DID_RESET << 16);
            cmd->scsi_done(cmd);
        }
    }
}

static int pvscsi_host_reset(struct scsi_cmnd *cmd)
{
    struct Scsi_Host *host = cmd->device->host;
    struct pvscsi_adapter *adapter = shost_priv(host);
    unsigned long flags;
    bool use_msg;

    scmd_printk(KERN_INFO, cmd, "SCSI Host reset\n");

    spin_lock_irqsave(&adapter->hw_lock, flags);

    use_msg = adapter->use_msg;

    if (use_msg) {
        adapter->use_msg = 0;
        spin_unlock_irqrestore(&adapter->hw_lock, flags);

        /*
         * Now that we know that the ISR won't add more work on the
         * workqueue we can safely flush any outstanding work.
         */
        flush_workqueue(adapter->workqueue);
        spin_lock_irqsave(&adapter->hw_lock, flags);
    }

    /*
     * We're going to tear down the entire ring structure and set it back
     * up, so stalling new requests until all completions are flushed and
     * the rings are back in place.
     */

    pvscsi_process_request_ring(adapter);

    ll_adapter_reset(adapter);

    /*
     * Now process any completions.  Note we do this AFTER adapter reset,
     * which is strange, but stops races where completions get posted
     * between processing the ring and issuing the reset.  The backend will
     * not touch the ring memory after reset, so the immediately pre-reset
     * completion ring state is still valid.
     */
    pvscsi_process_completion_ring(adapter);

    pvscsi_reset_all(adapter);
    adapter->use_msg = use_msg;
    pvscsi_setup_all_rings(adapter);
    pvscsi_unmask_intr(adapter);

    spin_unlock_irqrestore(&adapter->hw_lock, flags);

    return SUCCESS;
}

static int pvscsi_bus_reset(struct scsi_cmnd *cmd)
{
    struct Scsi_Host *host = cmd->device->host;
    struct pvscsi_adapter *adapter = shost_priv(host);
    unsigned long flags;

    scmd_printk(KERN_INFO, cmd, "SCSI Bus reset\n");

    /*
     * We don't want to queue new requests for this bus after
     * flushing all pending requests to emulation, since new
     * requests could then sneak in during this bus reset phase,
     * so take the lock now.
     */
    spin_lock_irqsave(&adapter->hw_lock, flags);

    pvscsi_process_request_ring(adapter);
    ll_bus_reset(adapter);
    pvscsi_process_completion_ring(adapter);

    spin_unlock_irqrestore(&adapter->hw_lock, flags);

    return SUCCESS;
}

static int pvscsi_device_reset(struct scsi_cmnd *cmd)
{
    struct Scsi_Host *host = cmd->device->host;
    struct pvscsi_adapter *adapter = shost_priv(host);
    unsigned long flags;

    scmd_printk(KERN_INFO, cmd, "SCSI device reset on scsi%u:%u\n",
            host->host_no, cmd->device->id);

    /*
     * We don't want to queue new requests for this device after flushing
     * all pending requests to emulation, since new requests could then
     * sneak in during this device reset phase, so take the lock now.
     */
    spin_lock_irqsave(&adapter->hw_lock, flags);

    pvscsi_process_request_ring(adapter);
    ll_device_reset(adapter, cmd->device->id);
    pvscsi_process_completion_ring(adapter);

    spin_unlock_irqrestore(&adapter->hw_lock, flags);

    return SUCCESS;
}

static struct scsi_host_template pvscsi_template;

static const char *pvscsi_info(struct Scsi_Host *host)
{
    struct pvscsi_adapter *adapter = shost_priv(host);
    static char buf[256];

    sprintf(buf, "VMware PVSCSI storage adapter rev %d, req/cmp/msg rings: "
        "%u/%u/%u pages, cmd_per_lun=%u", adapter->rev,
        adapter->req_pages, adapter->cmp_pages, adapter->msg_pages,
        pvscsi_template.cmd_per_lun);

    return buf;
}

static struct scsi_host_template pvscsi_template = {
    .module             = THIS_MODULE,
    .name               = "VMware PVSCSI Host Adapter",
    .proc_name          = "vmw_pvscsi",
    .info               = pvscsi_info,
    .queuecommand           = pvscsi_queue,
    .this_id            = -1,
    .sg_tablesize           = PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT,
    .dma_boundary           = UINT_MAX,
    .max_sectors            = 0xffff,
    .use_clustering         = ENABLE_CLUSTERING,
    .eh_abort_handler       = pvscsi_abort,
    .eh_device_reset_handler    = pvscsi_device_reset,
    .eh_bus_reset_handler       = pvscsi_bus_reset,
    .eh_host_reset_handler      = pvscsi_host_reset,
};

static void pvscsi_process_msg(const struct pvscsi_adapter *adapter,
                   const struct PVSCSIRingMsgDesc *e)
{
    struct PVSCSIRingsState *s = adapter->rings_state;
    struct Scsi_Host *host = adapter->host;
    struct scsi_device *sdev;

    printk(KERN_INFO "vmw_pvscsi: msg type: 0x%x - MSG RING: %u/%u (%u) \n",
           e->type, s->msgProdIdx, s->msgConsIdx, s->msgNumEntriesLog2);

    BUILD_BUG_ON(PVSCSI_MSG_LAST != 2);

    if (e->type == PVSCSI_MSG_DEV_ADDED) {
        struct PVSCSIMsgDescDevStatusChanged *desc;
        desc = (struct PVSCSIMsgDescDevStatusChanged *)e;

        printk(KERN_INFO
               "vmw_pvscsi: msg: device added at scsi%u:%u:%u\n",
               desc->bus, desc->target, desc->lun[1]);

        if (!scsi_host_get(host))
            return;

        sdev = scsi_device_lookup(host, desc->bus, desc->target,
                      desc->lun[1]);
        if (sdev) {
            printk(KERN_INFO "vmw_pvscsi: device already exists\n");
            scsi_device_put(sdev);
        } else
            scsi_add_device(adapter->host, desc->bus,
                    desc->target, desc->lun[1]);

        scsi_host_put(host);
    } else if (e->type == PVSCSI_MSG_DEV_REMOVED) {
        struct PVSCSIMsgDescDevStatusChanged *desc;
        desc = (struct PVSCSIMsgDescDevStatusChanged *)e;

        printk(KERN_INFO
               "vmw_pvscsi: msg: device removed at scsi%u:%u:%u\n",
               desc->bus, desc->target, desc->lun[1]);

        if (!scsi_host_get(host))
            return;

        sdev = scsi_device_lookup(host, desc->bus, desc->target,
                      desc->lun[1]);
        if (sdev) {
            scsi_remove_device(sdev);
            scsi_device_put(sdev);
        } else
            printk(KERN_INFO
                   "vmw_pvscsi: failed to lookup scsi%u:%u:%u\n",
                   desc->bus, desc->target, desc->lun[1]);

        scsi_host_put(host);
    }
}

static int pvscsi_msg_pending(const struct pvscsi_adapter *adapter)
{
    struct PVSCSIRingsState *s = adapter->rings_state;

    return s->msgProdIdx != s->msgConsIdx;
}

static void pvscsi_process_msg_ring(const struct pvscsi_adapter *adapter)
{
    struct PVSCSIRingsState *s = adapter->rings_state;
    struct PVSCSIRingMsgDesc *ring = adapter->msg_ring;
    u32 msg_entries = s->msgNumEntriesLog2;

    while (pvscsi_msg_pending(adapter)) {
        struct PVSCSIRingMsgDesc *e = ring + (s->msgConsIdx &
                              MASK(msg_entries));

        barrier();
        pvscsi_process_msg(adapter, e);
        barrier();
        s->msgConsIdx++;
    }
}

static void pvscsi_msg_workqueue_handler(struct work_struct *data)
{
    struct pvscsi_adapter *adapter;

    adapter = container_of(data, struct pvscsi_adapter, work);

    pvscsi_process_msg_ring(adapter);
}

static int pvscsi_setup_msg_workqueue(struct pvscsi_adapter *adapter)
{
    char name[32];

    if (!pvscsi_use_msg)
        return 0;

    pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND,
             PVSCSI_CMD_SETUP_MSG_RING);

    if (pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_COMMAND_STATUS) == -1)
        return 0;

    snprintf(name, sizeof(name),
         "vmw_pvscsi_wq_%u", adapter->host->host_no);

    adapter->workqueue = create_singlethread_workqueue(name);
    if (!adapter->workqueue) {
        printk(KERN_ERR "vmw_pvscsi: failed to create work queue\n");
        return 0;
    }
    INIT_WORK(&adapter->work, pvscsi_msg_workqueue_handler);

    return 1;
}

static irqreturn_t pvscsi_isr(int irq, void *devp)
{
    struct pvscsi_adapter *adapter = devp;
    int handled;

    if (adapter->use_msi || adapter->use_msix)
        handled = true;
    else {
        u32 val = pvscsi_read_intr_status(adapter);
        handled = (val & PVSCSI_INTR_ALL_SUPPORTED) != 0;
        if (handled)
            pvscsi_write_intr_status(devp, val);
    }

    if (handled) {
        unsigned long flags;

        spin_lock_irqsave(&adapter->hw_lock, flags);

        pvscsi_process_completion_ring(adapter);
        if (adapter->use_msg && pvscsi_msg_pending(adapter))
            queue_work(adapter->workqueue, &adapter->work);

        spin_unlock_irqrestore(&adapter->hw_lock, flags);
    }

    return IRQ_RETVAL(handled);
}

static void pvscsi_free_sgls(const struct pvscsi_adapter *adapter)
{
    struct pvscsi_ctx *ctx = adapter->cmd_map;
    unsigned i;

    for (i = 0; i < adapter->req_depth; ++i, ++ctx)
        free_pages((unsigned long)ctx->sgl, get_order(SGL_SIZE));
}

static int pvscsi_setup_msix(const struct pvscsi_adapter *adapter,
                 unsigned int *irq)
{
    struct msix_entry entry = { 0, PVSCSI_VECTOR_COMPLETION };
    int ret;

    ret = pci_enable_msix(adapter->dev, &entry, 1);
    if (ret)
        return ret;

    *irq = entry.vector;

    return 0;
}

static void pvscsi_shutdown_intr(struct pvscsi_adapter *adapter)
{
    if (adapter->irq) {
        free_irq(adapter->irq, adapter);
        adapter->irq = 0;
    }
    if (adapter->use_msi) {
        pci_disable_msi(adapter->dev);
        adapter->use_msi = 0;
    } else if (adapter->use_msix) {
        pci_disable_msix(adapter->dev);
        adapter->use_msix = 0;
    }
}

static void pvscsi_release_resources(struct pvscsi_adapter *adapter)
{
    pvscsi_shutdown_intr(adapter);

    if (adapter->workqueue)
        destroy_workqueue(adapter->workqueue);

    if (adapter->mmioBase)
        pci_iounmap(adapter->dev, adapter->mmioBase);

    pci_release_regions(adapter->dev);

    if (adapter->cmd_map) {
        pvscsi_free_sgls(adapter);
        kfree(adapter->cmd_map);
    }

    if (adapter->rings_state)
        pci_free_consistent(adapter->dev, PAGE_SIZE,
                    adapter->rings_state, adapter->ringStatePA);

    if (adapter->req_ring)
        pci_free_consistent(adapter->dev,
                    adapter->req_pages * PAGE_SIZE,
                    adapter->req_ring, adapter->reqRingPA);

    if (adapter->cmp_ring)
        pci_free_consistent(adapter->dev,
                    adapter->cmp_pages * PAGE_SIZE,
                    adapter->cmp_ring, adapter->cmpRingPA);

    if (adapter->msg_ring)
        pci_free_consistent(adapter->dev,
                    adapter->msg_pages * PAGE_SIZE,
                    adapter->msg_ring, adapter->msgRingPA);
}

/*
 * Allocate scatter gather lists.
 *
 * These are statically allocated.  Trying to be clever was not worth it.
 *
 * Dynamic allocation can fail, and we can't go deep into the memory
 * allocator, since we're a SCSI driver, and trying too hard to allocate
 * memory might generate disk I/O.  We also don't want to fail disk I/O
 * in that case because we can't get an allocation - the I/O could be
 * trying to swap out data to free memory.  Since that is pathological,
 * just use a statically allocated scatter list.
 *
 */
static int __devinit pvscsi_allocate_sg(struct pvscsi_adapter *adapter)
{
    struct pvscsi_ctx *ctx;
    int i;

    ctx = adapter->cmd_map;
    BUILD_BUG_ON(sizeof(struct pvscsi_sg_list) > SGL_SIZE);

    for (i = 0; i < adapter->req_depth; ++i, ++ctx) {
        ctx->sgl = (void *)__get_free_pages(GFP_KERNEL,
                            get_order(SGL_SIZE));
        ctx->sglPA = 0;
        BUG_ON(!IS_ALIGNED(((unsigned long)ctx->sgl), PAGE_SIZE));
        if (!ctx->sgl) {
            for (; i >= 0; --i, --ctx) {
                free_pages((unsigned long)ctx->sgl,
                       get_order(SGL_SIZE));
                ctx->sgl = NULL;
            }
            return -ENOMEM;
        }
    }

    return 0;
}

/*
 * Query the device, fetch the config info and return the
 * maximum number of targets on the adapter. In case of
 * failure due to any reason return default i.e. 16.
 */
static u32 pvscsi_get_max_targets(struct pvscsi_adapter *adapter)
{
    struct PVSCSICmdDescConfigCmd cmd;
    struct PVSCSIConfigPageHeader *header;
    struct device *dev;
    dma_addr_t configPagePA;
    void *config_page;
    u32 numPhys = 16;

    dev = pvscsi_dev(adapter);
    config_page = pci_alloc_consistent(adapter->dev, PAGE_SIZE,
                       &configPagePA);
    if (!config_page) {
        dev_warn(dev, "vmw_pvscsi: failed to allocate memory for config page\n");
        goto exit;
    }
    BUG_ON(configPagePA & ~PAGE_MASK);

    /* Fetch config info from the device. */
    cmd.configPageAddress = ((u64)PVSCSI_CONFIG_CONTROLLER_ADDRESS) << 32;
    cmd.configPageNum = PVSCSI_CONFIG_PAGE_CONTROLLER;
    cmd.cmpAddr = configPagePA;
    cmd._pad = 0;

    /*
     * Mark the completion page header with error values. If the device
     * completes the command successfully, it sets the status values to
     * indicate success.
     */
    header = config_page;
    memset(header, 0, sizeof *header);
    header->hostStatus = BTSTAT_INVPARAM;
    header->scsiStatus = SDSTAT_CHECK;

    pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_CONFIG, &cmd, sizeof cmd);

    if (header->hostStatus == BTSTAT_SUCCESS &&
        header->scsiStatus == SDSTAT_GOOD) {
        struct PVSCSIConfigPageController *config;

        config = config_page;
        numPhys = config->numPhys;
    } else
        dev_warn(dev, "vmw_pvscsi: PVSCSI_CMD_CONFIG failed. hostStatus = 0x%x, scsiStatus = 0x%x\n",
             header->hostStatus, header->scsiStatus);
    pci_free_consistent(adapter->dev, PAGE_SIZE, config_page, configPagePA);
exit:
    return numPhys;
}

static int __devinit pvscsi_probe(struct pci_dev *pdev,
                  const struct pci_device_id *id)
{
    struct pvscsi_adapter *adapter;
    struct Scsi_Host *host;
    struct device *dev;
    unsigned int i;
    unsigned long flags = 0;
    int error;

    error = -ENODEV;

    if (pci_enable_device(pdev))
        return error;

    if (pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) == 0 &&
        pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)) == 0) {
        printk(KERN_INFO "vmw_pvscsi: using 64bit dma\n");
    } else if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) == 0 &&
           pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)) == 0) {
        printk(KERN_INFO "vmw_pvscsi: using 32bit dma\n");
    } else {
        printk(KERN_ERR "vmw_pvscsi: failed to set DMA mask\n");
        goto out_disable_device;
    }

    pvscsi_template.can_queue =
        min(PVSCSI_MAX_NUM_PAGES_REQ_RING, pvscsi_ring_pages) *
        PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
    pvscsi_template.cmd_per_lun =
        min(pvscsi_template.can_queue, pvscsi_cmd_per_lun);
    host = scsi_host_alloc(&pvscsi_template, sizeof(struct pvscsi_adapter));
    if (!host) {
        printk(KERN_ERR "vmw_pvscsi: failed to allocate host\n");
        goto out_disable_device;
    }

    adapter = shost_priv(host);
    memset(adapter, 0, sizeof(*adapter));
    adapter->dev  = pdev;
    adapter->host = host;

    spin_lock_init(&adapter->hw_lock);

    host->max_channel = 0;
    host->max_id      = 16;
    host->max_lun     = 1;
    host->max_cmd_len = 16;

    adapter->rev = pdev->revision;

    if (pci_request_regions(pdev, "vmw_pvscsi")) {
        printk(KERN_ERR "vmw_pvscsi: pci memory selection failed\n");
        goto out_free_host;
    }

    for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
        if ((pci_resource_flags(pdev, i) & PCI_BASE_ADDRESS_SPACE_IO))
            continue;

        if (pci_resource_len(pdev, i) < PVSCSI_MEM_SPACE_SIZE)
            continue;

        break;
    }

    if (i == DEVICE_COUNT_RESOURCE) {
        printk(KERN_ERR
               "vmw_pvscsi: adapter has no suitable MMIO region\n");
        goto out_release_resources;
    }

    adapter->mmioBase = pci_iomap(pdev, i, PVSCSI_MEM_SPACE_SIZE);

    if (!adapter->mmioBase) {
        printk(KERN_ERR
               "vmw_pvscsi: can't iomap for BAR %d memsize %lu\n",
               i, PVSCSI_MEM_SPACE_SIZE);
        goto out_release_resources;
    }

    pci_set_master(pdev);
    pci_set_drvdata(pdev, host);

    ll_adapter_reset(adapter);

    adapter->use_msg = pvscsi_setup_msg_workqueue(adapter);

    error = pvscsi_allocate_rings(adapter);
    if (error) {
        printk(KERN_ERR "vmw_pvscsi: unable to allocate ring memory\n");
        goto out_release_resources;
    }

    /*
     * Ask the device for max number of targets.
     */
    host->max_id = pvscsi_get_max_targets(adapter);
    dev = pvscsi_dev(adapter);
    dev_info(dev, "vmw_pvscsi: host->max_id: %u\n", host->max_id);

    /*
     * From this point on we should reset the adapter if anything goes
     * wrong.
     */
    pvscsi_setup_all_rings(adapter);

    adapter->cmd_map = kcalloc(adapter->req_depth,
                   sizeof(struct pvscsi_ctx), GFP_KERNEL);
    if (!adapter->cmd_map) {
        printk(KERN_ERR "vmw_pvscsi: failed to allocate memory.\n");
        error = -ENOMEM;
        goto out_reset_adapter;
    }

    INIT_LIST_HEAD(&adapter->cmd_pool);
    for (i = 0; i < adapter->req_depth; i++) {
        struct pvscsi_ctx *ctx = adapter->cmd_map + i;
        list_add(&ctx->list, &adapter->cmd_pool);
    }

    error = pvscsi_allocate_sg(adapter);
    if (error) {
        printk(KERN_ERR "vmw_pvscsi: unable to allocate s/g table\n");
        goto out_reset_adapter;
    }

    if (!pvscsi_disable_msix &&
        pvscsi_setup_msix(adapter, &adapter->irq) == 0) {
        printk(KERN_INFO "vmw_pvscsi: using MSI-X\n");
        adapter->use_msix = 1;
    } else if (!pvscsi_disable_msi && pci_enable_msi(pdev) == 0) {
        printk(KERN_INFO "vmw_pvscsi: using MSI\n");
        adapter->use_msi = 1;
        adapter->irq = pdev->irq;
    } else {
        printk(KERN_INFO "vmw_pvscsi: using INTx\n");
        adapter->irq = pdev->irq;
        flags = IRQF_SHARED;
    }

    error = request_irq(adapter->irq, pvscsi_isr, flags,
                "vmw_pvscsi", adapter);
    if (error) {
        printk(KERN_ERR
               "vmw_pvscsi: unable to request IRQ: %d\n", error);
        adapter->irq = 0;
        goto out_reset_adapter;
    }

    error = scsi_add_host(host, &pdev->dev);
    if (error) {
        printk(KERN_ERR
               "vmw_pvscsi: scsi_add_host failed: %d\n", error);
        goto out_reset_adapter;
    }

    dev_info(&pdev->dev, "VMware PVSCSI rev %d host #%u\n",
         adapter->rev, host->host_no);

    pvscsi_unmask_intr(adapter);

    scsi_scan_host(host);

    return 0;

out_reset_adapter:
    ll_adapter_reset(adapter);
out_release_resources:
    pvscsi_release_resources(adapter);
out_free_host:
    scsi_host_put(host);
out_disable_device:
    pci_set_drvdata(pdev, NULL);
    pci_disable_device(pdev);

    return error;
}

static void __pvscsi_shutdown(struct pvscsi_adapter *adapter)
{
    pvscsi_mask_intr(adapter);

    if (adapter->workqueue)
        flush_workqueue(adapter->workqueue);

    pvscsi_shutdown_intr(adapter);

    pvscsi_process_request_ring(adapter);
    pvscsi_process_completion_ring(adapter);
    ll_adapter_reset(adapter);
}

static void pvscsi_shutdown(struct pci_dev *dev)
{
    struct Scsi_Host *host = pci_get_drvdata(dev);
    struct pvscsi_adapter *adapter = shost_priv(host);

    __pvscsi_shutdown(adapter);
}

static void pvscsi_remove(struct pci_dev *pdev)
{
    struct Scsi_Host *host = pci_get_drvdata(pdev);
    struct pvscsi_adapter *adapter = shost_priv(host);

    scsi_remove_host(host);

    __pvscsi_shutdown(adapter);
    pvscsi_release_resources(adapter);

    scsi_host_put(host);

    pci_set_drvdata(pdev, NULL);
    pci_disable_device(pdev);
}

static struct pci_driver pvscsi_pci_driver = {
    .name       = "vmw_pvscsi",
    .id_table   = pvscsi_pci_tbl,
    .probe      = pvscsi_probe,
    .remove     = __devexit_p(pvscsi_remove),
    .shutdown       = pvscsi_shutdown,
};

static int __init pvscsi_init(void)
{
    pr_info("%s - version %s\n",
        PVSCSI_LINUX_DRIVER_DESC, PVSCSI_DRIVER_VERSION_STRING);
    return pci_register_driver(&pvscsi_pci_driver);
}

static void __exit pvscsi_exit(void)
{
    pci_unregister_driver(&pvscsi_pci_driver);
}

module_init(pvscsi_init);
module_exit(pvscsi_exit);