/*
 * This file is part of the Chelsio FCoE driver for Linux.
 *
 * Copyright (c) 2008-2012 Chelsio Communications, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/device.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/module.h>
#include <asm/unaligned.h>
#include <asm/page.h>
#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport_fc.h>

#include "csio_hw.h"
#include "csio_lnode.h"
#include "csio_rnode.h"
#include "csio_scsi.h"
#include "csio_init.h"

int csio_scsi_eqsize = 65536;
int csio_scsi_iqlen = 128;
int csio_scsi_ioreqs = 2048;
uint32_t csio_max_scan_tmo;
uint32_t csio_delta_scan_tmo = 5;
int csio_lun_qdepth = 32;

static int csio_ddp_descs = 128;

static int csio_do_abrt_cls(struct csio_hw *,
                                      struct csio_ioreq *, bool);

static void csio_scsis_uninit(struct csio_ioreq *, enum csio_scsi_ev);
static void csio_scsis_io_active(struct csio_ioreq *, enum csio_scsi_ev);
static void csio_scsis_tm_active(struct csio_ioreq *, enum csio_scsi_ev);
static void csio_scsis_aborting(struct csio_ioreq *, enum csio_scsi_ev);
static void csio_scsis_closing(struct csio_ioreq *, enum csio_scsi_ev);
static void csio_scsis_shost_cmpl_await(struct csio_ioreq *, enum csio_scsi_ev);

/*
 * csio_scsi_match_io - Match an ioreq with the given SCSI level data.
 * @ioreq: The I/O request
 * @sld: Level information
 *
 * Should be called with lock held.
 *
 */
static bool
csio_scsi_match_io(struct csio_ioreq *ioreq, struct csio_scsi_level_data *sld)
{
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(ioreq);

        switch (sld->level) {
        case CSIO_LEV_LUN:
                if (scmnd == NULL)
                        return false;

                return ((ioreq->lnode == sld->lnode) &&
                        (ioreq->rnode == sld->rnode) &&
                        ((uint64_t)scmnd->device->lun == sld->oslun));

        case CSIO_LEV_RNODE:
                return ((ioreq->lnode == sld->lnode) &&
                                (ioreq->rnode == sld->rnode));
        case CSIO_LEV_LNODE:
                return (ioreq->lnode == sld->lnode);
        case CSIO_LEV_ALL:
                return true;
        default:
                return false;
        }
}

/*
 * csio_scsi_gather_active_ios - Gather active I/Os based on level
 * @scm: SCSI module
 * @sld: Level information
 * @dest: The queue where these I/Os have to be gathered.
 *
 * Should be called with lock held.
 */
static void
csio_scsi_gather_active_ios(struct csio_scsim *scm,
                            struct csio_scsi_level_data *sld,
                            struct list_head *dest)
{
        struct list_head *tmp, *next;

        if (list_empty(&scm->active_q))
                return;

        /* Just splice the entire active_q into dest */
        if (sld->level == CSIO_LEV_ALL) {
                list_splice_tail_init(&scm->active_q, dest);
                return;
        }

        list_for_each_safe(tmp, next, &scm->active_q) {
                if (csio_scsi_match_io((struct csio_ioreq *)tmp, sld)) {
                        list_del_init(tmp);
                        list_add_tail(tmp, dest);
                }
        }
}

static inline bool
csio_scsi_itnexus_loss_error(uint16_t error)
{
        switch (error) {
        case FW_ERR_LINK_DOWN:
        case FW_RDEV_NOT_READY:
        case FW_ERR_RDEV_LOST:
        case FW_ERR_RDEV_LOGO:
        case FW_ERR_RDEV_IMPL_LOGO:
                return 1;
        }
        return 0;
}

static inline void
csio_scsi_tag(struct scsi_cmnd *scmnd, uint8_t *tag, uint8_t hq,
              uint8_t oq, uint8_t sq)
{
        char stag[2];

        if (scsi_populate_tag_msg(scmnd, stag)) {
                switch (stag[0]) {
                case HEAD_OF_QUEUE_TAG:
                        *tag = hq;
                        break;
                case ORDERED_QUEUE_TAG:
                        *tag = oq;
                        break;
                default:
                        *tag = sq;
                        break;
                }
        } else
                *tag = 0;
}

/*
 * csio_scsi_fcp_cmnd - Frame the SCSI FCP command paylod.
 * @req: IO req structure.
 * @addr: DMA location to place the payload.
 *
 * This routine is shared between FCP_WRITE, FCP_READ and FCP_CMD requests.
 */
static inline void
csio_scsi_fcp_cmnd(struct csio_ioreq *req, void *addr)
{
        struct fcp_cmnd *fcp_cmnd = (struct fcp_cmnd *)addr;
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(req);

        /* Check for Task Management */
        if (likely(scmnd->SCp.Message == 0)) {
                int_to_scsilun(scmnd->device->lun, &fcp_cmnd->fc_lun);
                fcp_cmnd->fc_tm_flags = 0;
                fcp_cmnd->fc_cmdref = 0;
                fcp_cmnd->fc_pri_ta = 0;

                memcpy(fcp_cmnd->fc_cdb, scmnd->cmnd, 16);
                csio_scsi_tag(scmnd, &fcp_cmnd->fc_pri_ta,
                              FCP_PTA_HEADQ, FCP_PTA_ORDERED, FCP_PTA_SIMPLE);
                fcp_cmnd->fc_dl = cpu_to_be32(scsi_bufflen(scmnd));

                if (req->nsge)
                        if (req->datadir == DMA_TO_DEVICE)
                                fcp_cmnd->fc_flags = FCP_CFL_WRDATA;
                        else
                                fcp_cmnd->fc_flags = FCP_CFL_RDDATA;
                else
                        fcp_cmnd->fc_flags = 0;
        } else {
                memset(fcp_cmnd, 0, sizeof(*fcp_cmnd));
                int_to_scsilun(scmnd->device->lun, &fcp_cmnd->fc_lun);
                fcp_cmnd->fc_tm_flags = (uint8_t)scmnd->SCp.Message;
        }
}

/*
 * csio_scsi_init_cmd_wr - Initialize the SCSI CMD WR.
 * @req: IO req structure.
 * @addr: DMA location to place the payload.
 * @size: Size of WR (including FW WR + immed data + rsp SG entry
 *
 * Wrapper for populating fw_scsi_cmd_wr.
 */
static inline void
csio_scsi_init_cmd_wr(struct csio_ioreq *req, void *addr, uint32_t size)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_rnode *rn = req->rnode;
        struct fw_scsi_cmd_wr *wr = (struct fw_scsi_cmd_wr *)addr;
        struct csio_dma_buf *dma_buf;
        uint8_t imm = csio_hw_to_scsim(hw)->proto_cmd_len;

        wr->op_immdlen = cpu_to_be32(FW_WR_OP(FW_SCSI_CMD_WR) |
                                          FW_SCSI_CMD_WR_IMMDLEN(imm));
        wr->flowid_len16 = cpu_to_be32(FW_WR_FLOWID(rn->flowid) |
                                            FW_WR_LEN16(
                                                DIV_ROUND_UP(size, 16)));

        wr->cookie = (uintptr_t) req;
        wr->iqid = cpu_to_be16(csio_q_physiqid(hw, req->iq_idx));
        wr->tmo_val = (uint8_t) req->tmo;
        wr->r3 = 0;
        memset(&wr->r5, 0, 8);

        /* Get RSP DMA buffer */
        dma_buf = &req->dma_buf;

        /* Prepare RSP SGL */
        wr->rsp_dmalen = cpu_to_be32(dma_buf->len);
        wr->rsp_dmaaddr = cpu_to_be64(dma_buf->paddr);

        wr->r6 = 0;

        wr->u.fcoe.ctl_pri = 0;
        wr->u.fcoe.cp_en_class = 0;
        wr->u.fcoe.r4_lo[0] = 0;
        wr->u.fcoe.r4_lo[1] = 0;

        /* Frame a FCP command */
        csio_scsi_fcp_cmnd(req, (void *)((uintptr_t)addr +
                                    sizeof(struct fw_scsi_cmd_wr)));
}

#define CSIO_SCSI_CMD_WR_SZ(_imm)                                       \
        (sizeof(struct fw_scsi_cmd_wr) +                /* WR size */   \
         ALIGN((_imm), 16))                             /* Immed data */

#define CSIO_SCSI_CMD_WR_SZ_16(_imm)                                    \
                        (ALIGN(CSIO_SCSI_CMD_WR_SZ((_imm)), 16))

/*
 * csio_scsi_cmd - Create a SCSI CMD WR.
 * @req: IO req structure.
 *
 * Gets a WR slot in the ingress queue and initializes it with SCSI CMD WR.
 *
 */
static inline void
csio_scsi_cmd(struct csio_ioreq *req)
{
        struct csio_wr_pair wrp;
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);
        uint32_t size = CSIO_SCSI_CMD_WR_SZ_16(scsim->proto_cmd_len);

        req->drv_status = csio_wr_get(hw, req->eq_idx, size, &wrp);
        if (unlikely(req->drv_status != 0))
                return;

        if (wrp.size1 >= size) {
                /* Initialize WR in one shot */
                csio_scsi_init_cmd_wr(req, wrp.addr1, size);
        } else {
                uint8_t *tmpwr = csio_q_eq_wrap(hw, req->eq_idx);

                /*
                 * Make a temporary copy of the WR and write back
                 * the copy into the WR pair.
                 */
                csio_scsi_init_cmd_wr(req, (void *)tmpwr, size);
                memcpy(wrp.addr1, tmpwr, wrp.size1);
                memcpy(wrp.addr2, tmpwr + wrp.size1, size - wrp.size1);
        }
}

/*
 * csio_scsi_init_ulptx_dsgl - Fill in a ULP_TX_SC_DSGL
 * @hw: HW module
 * @req: IO request
 * @sgl: ULP TX SGL pointer.
 *
 */
static inline void
csio_scsi_init_ultptx_dsgl(struct csio_hw *hw, struct csio_ioreq *req,
                           struct ulptx_sgl *sgl)
{
        struct ulptx_sge_pair *sge_pair = NULL;
        struct scatterlist *sgel;
        uint32_t i = 0;
        uint32_t xfer_len;
        struct list_head *tmp;
        struct csio_dma_buf *dma_buf;
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(req);

        sgl->cmd_nsge = htonl(ULPTX_CMD(ULP_TX_SC_DSGL) | ULPTX_MORE |
                                     ULPTX_NSGE(req->nsge));
        /* Now add the data SGLs */
        if (likely(!req->dcopy)) {
                scsi_for_each_sg(scmnd, sgel, req->nsge, i) {
                        if (i == 0) {
                                sgl->addr0 = cpu_to_be64(sg_dma_address(sgel));
                                sgl->len0 = cpu_to_be32(sg_dma_len(sgel));
                                sge_pair = (struct ulptx_sge_pair *)(sgl + 1);
                                continue;
                        }
                        if ((i - 1) & 0x1) {
                                sge_pair->addr[1] = cpu_to_be64(
                                                        sg_dma_address(sgel));
                                sge_pair->len[1] = cpu_to_be32(
                                                        sg_dma_len(sgel));
                                sge_pair++;
                        } else {
                                sge_pair->addr[0] = cpu_to_be64(
                                                        sg_dma_address(sgel));
                                sge_pair->len[0] = cpu_to_be32(
                                                        sg_dma_len(sgel));
                        }
                }
        } else {
                /* Program sg elements with driver's DDP buffer */
                xfer_len = scsi_bufflen(scmnd);
                list_for_each(tmp, &req->gen_list) {
                        dma_buf = (struct csio_dma_buf *)tmp;
                        if (i == 0) {
                                sgl->addr0 = cpu_to_be64(dma_buf->paddr);
                                sgl->len0 = cpu_to_be32(
                                                min(xfer_len, dma_buf->len));
                                sge_pair = (struct ulptx_sge_pair *)(sgl + 1);
                        } else if ((i - 1) & 0x1) {
                                sge_pair->addr[1] = cpu_to_be64(dma_buf->paddr);
                                sge_pair->len[1] = cpu_to_be32(
                                                min(xfer_len, dma_buf->len));
                                sge_pair++;
                        } else {
                                sge_pair->addr[0] = cpu_to_be64(dma_buf->paddr);
                                sge_pair->len[0] = cpu_to_be32(
                                                min(xfer_len, dma_buf->len));
                        }
                        xfer_len -= min(xfer_len, dma_buf->len);
                        i++;
                }
        }
}

/*
 * csio_scsi_init_read_wr - Initialize the READ SCSI WR.
 * @req: IO req structure.
 * @wrp: DMA location to place the payload.
 * @size: Size of WR (including FW WR + immed data + rsp SG entry + data SGL
 *
 * Wrapper for populating fw_scsi_read_wr.
 */
static inline void
csio_scsi_init_read_wr(struct csio_ioreq *req, void *wrp, uint32_t size)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_rnode *rn = req->rnode;
        struct fw_scsi_read_wr *wr = (struct fw_scsi_read_wr *)wrp;
        struct ulptx_sgl *sgl;
        struct csio_dma_buf *dma_buf;
        uint8_t imm = csio_hw_to_scsim(hw)->proto_cmd_len;
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(req);

        wr->op_immdlen = cpu_to_be32(FW_WR_OP(FW_SCSI_READ_WR) |
                                     FW_SCSI_READ_WR_IMMDLEN(imm));
        wr->flowid_len16 = cpu_to_be32(FW_WR_FLOWID(rn->flowid) |
                                       FW_WR_LEN16(DIV_ROUND_UP(size, 16)));
        wr->cookie = (uintptr_t)req;
        wr->iqid = cpu_to_be16(csio_q_physiqid(hw, req->iq_idx));
        wr->tmo_val = (uint8_t)(req->tmo);
        wr->use_xfer_cnt = 1;
        wr->xfer_cnt = cpu_to_be32(scsi_bufflen(scmnd));
        wr->ini_xfer_cnt = cpu_to_be32(scsi_bufflen(scmnd));
        /* Get RSP DMA buffer */
        dma_buf = &req->dma_buf;

        /* Prepare RSP SGL */
        wr->rsp_dmalen = cpu_to_be32(dma_buf->len);
        wr->rsp_dmaaddr = cpu_to_be64(dma_buf->paddr);

        wr->r4 = 0;

        wr->u.fcoe.ctl_pri = 0;
        wr->u.fcoe.cp_en_class = 0;
        wr->u.fcoe.r3_lo[0] = 0;
        wr->u.fcoe.r3_lo[1] = 0;
        csio_scsi_fcp_cmnd(req, (void *)((uintptr_t)wrp +
                                        sizeof(struct fw_scsi_read_wr)));

        /* Move WR pointer past command and immediate data */
        sgl = (struct ulptx_sgl *)((uintptr_t)wrp +
                              sizeof(struct fw_scsi_read_wr) + ALIGN(imm, 16));

        /* Fill in the DSGL */
        csio_scsi_init_ultptx_dsgl(hw, req, sgl);
}

/*
 * csio_scsi_init_write_wr - Initialize the WRITE SCSI WR.
 * @req: IO req structure.
 * @wrp: DMA location to place the payload.
 * @size: Size of WR (including FW WR + immed data + rsp SG entry + data SGL
 *
 * Wrapper for populating fw_scsi_write_wr.
 */
static inline void
csio_scsi_init_write_wr(struct csio_ioreq *req, void *wrp, uint32_t size)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_rnode *rn = req->rnode;
        struct fw_scsi_write_wr *wr = (struct fw_scsi_write_wr *)wrp;
        struct ulptx_sgl *sgl;
        struct csio_dma_buf *dma_buf;
        uint8_t imm = csio_hw_to_scsim(hw)->proto_cmd_len;
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(req);

        wr->op_immdlen = cpu_to_be32(FW_WR_OP(FW_SCSI_WRITE_WR) |
                                     FW_SCSI_WRITE_WR_IMMDLEN(imm));
        wr->flowid_len16 = cpu_to_be32(FW_WR_FLOWID(rn->flowid) |
                                       FW_WR_LEN16(DIV_ROUND_UP(size, 16)));
        wr->cookie = (uintptr_t)req;
        wr->iqid = cpu_to_be16(csio_q_physiqid(hw, req->iq_idx));
        wr->tmo_val = (uint8_t)(req->tmo);
        wr->use_xfer_cnt = 1;
        wr->xfer_cnt = cpu_to_be32(scsi_bufflen(scmnd));
        wr->ini_xfer_cnt = cpu_to_be32(scsi_bufflen(scmnd));
        /* Get RSP DMA buffer */
        dma_buf = &req->dma_buf;

        /* Prepare RSP SGL */
        wr->rsp_dmalen = cpu_to_be32(dma_buf->len);
        wr->rsp_dmaaddr = cpu_to_be64(dma_buf->paddr);

        wr->r4 = 0;

        wr->u.fcoe.ctl_pri = 0;
        wr->u.fcoe.cp_en_class = 0;
        wr->u.fcoe.r3_lo[0] = 0;
        wr->u.fcoe.r3_lo[1] = 0;
        csio_scsi_fcp_cmnd(req, (void *)((uintptr_t)wrp +
                                        sizeof(struct fw_scsi_write_wr)));

        /* Move WR pointer past command and immediate data */
        sgl = (struct ulptx_sgl *)((uintptr_t)wrp +
                              sizeof(struct fw_scsi_write_wr) + ALIGN(imm, 16));

        /* Fill in the DSGL */
        csio_scsi_init_ultptx_dsgl(hw, req, sgl);
}

/* Calculate WR size needed for fw_scsi_read_wr/fw_scsi_write_wr */
#define CSIO_SCSI_DATA_WRSZ(req, oper, sz, imm)                                \
do {                                                                           \
        (sz) = sizeof(struct fw_scsi_##oper##_wr) +     /* WR size */          \
               ALIGN((imm), 16) +                       /* Immed data */       \
               sizeof(struct ulptx_sgl);                /* ulptx_sgl */        \
                                                                               \
        if (unlikely((req)->nsge > 1))                                         \
                (sz) += (sizeof(struct ulptx_sge_pair) *                       \
                                (ALIGN(((req)->nsge - 1), 2) / 2));            \
                                                        /* Data SGE */         \
} while (0)

/*
 * csio_scsi_read - Create a SCSI READ WR.
 * @req: IO req structure.
 *
 * Gets a WR slot in the ingress queue and initializes it with
 * SCSI READ WR.
 *
 */
static inline void
csio_scsi_read(struct csio_ioreq *req)
{
        struct csio_wr_pair wrp;
        uint32_t size;
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);

        CSIO_SCSI_DATA_WRSZ(req, read, size, scsim->proto_cmd_len);
        size = ALIGN(size, 16);

        req->drv_status = csio_wr_get(hw, req->eq_idx, size, &wrp);
        if (likely(req->drv_status == 0)) {
                if (likely(wrp.size1 >= size)) {
                        /* Initialize WR in one shot */
                        csio_scsi_init_read_wr(req, wrp.addr1, size);
                } else {
                        uint8_t *tmpwr = csio_q_eq_wrap(hw, req->eq_idx);
                        /*
                         * Make a temporary copy of the WR and write back
                         * the copy into the WR pair.
                         */
                        csio_scsi_init_read_wr(req, (void *)tmpwr, size);
                        memcpy(wrp.addr1, tmpwr, wrp.size1);
                        memcpy(wrp.addr2, tmpwr + wrp.size1, size - wrp.size1);
                }
        }
}

/*
 * csio_scsi_write - Create a SCSI WRITE WR.
 * @req: IO req structure.
 *
 * Gets a WR slot in the ingress queue and initializes it with
 * SCSI WRITE WR.
 *
 */
static inline void
csio_scsi_write(struct csio_ioreq *req)
{
        struct csio_wr_pair wrp;
        uint32_t size;
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);

        CSIO_SCSI_DATA_WRSZ(req, write, size, scsim->proto_cmd_len);
        size = ALIGN(size, 16);

        req->drv_status = csio_wr_get(hw, req->eq_idx, size, &wrp);
        if (likely(req->drv_status == 0)) {
                if (likely(wrp.size1 >= size)) {
                        /* Initialize WR in one shot */
                        csio_scsi_init_write_wr(req, wrp.addr1, size);
                } else {
                        uint8_t *tmpwr = csio_q_eq_wrap(hw, req->eq_idx);
                        /*
                         * Make a temporary copy of the WR and write back
                         * the copy into the WR pair.
                         */
                        csio_scsi_init_write_wr(req, (void *)tmpwr, size);
                        memcpy(wrp.addr1, tmpwr, wrp.size1);
                        memcpy(wrp.addr2, tmpwr + wrp.size1, size - wrp.size1);
                }
        }
}

/*
 * csio_setup_ddp - Setup DDP buffers for Read request.
 * @req: IO req structure.
 *
 * Checks SGLs/Data buffers are virtually contiguous required for DDP.
 * If contiguous,driver posts SGLs in the WR otherwise post internal
 * buffers for such request for DDP.
 */
static inline void
csio_setup_ddp(struct csio_scsim *scsim, struct csio_ioreq *req)
{
#ifdef __CSIO_DEBUG__
        struct csio_hw *hw = req->lnode->hwp;
#endif
        struct scatterlist *sgel = NULL;
        struct scsi_cmnd *scmnd = csio_scsi_cmnd(req);
        uint64_t sg_addr = 0;
        uint32_t ddp_pagesz = 4096;
        uint32_t buf_off;
        struct csio_dma_buf *dma_buf = NULL;
        uint32_t alloc_len = 0;
        uint32_t xfer_len = 0;
        uint32_t sg_len = 0;
        uint32_t i;

        scsi_for_each_sg(scmnd, sgel, req->nsge, i) {
                sg_addr = sg_dma_address(sgel);
                sg_len  = sg_dma_len(sgel);

                buf_off = sg_addr & (ddp_pagesz - 1);

                /* Except 1st buffer,all buffer addr have to be Page aligned */
                if (i != 0 && buf_off) {
                        csio_dbg(hw, "SGL addr not DDP aligned (%llx:%d)\n",
                                 sg_addr, sg_len);
                        goto unaligned;
                }

                /* Except last buffer,all buffer must end on page boundary */
                if ((i != (req->nsge - 1)) &&
                        ((buf_off + sg_len) & (ddp_pagesz - 1))) {
                        csio_dbg(hw,
                                 "SGL addr not ending on page boundary"
                                 "(%llx:%d)\n", sg_addr, sg_len);
                        goto unaligned;
                }
        }

        /* SGL's are virtually contiguous. HW will DDP to SGLs */
        req->dcopy = 0;
        csio_scsi_read(req);

        return;

unaligned:
        CSIO_INC_STATS(scsim, n_unaligned);
        /*
         * For unaligned SGLs, driver will allocate internal DDP buffer.
         * Once command is completed data from DDP buffer copied to SGLs
         */
        req->dcopy = 1;

        /* Use gen_list to store the DDP buffers */
        INIT_LIST_HEAD(&req->gen_list);
        xfer_len = scsi_bufflen(scmnd);

        i = 0;
        /* Allocate ddp buffers for this request */
        while (alloc_len < xfer_len) {
                dma_buf = csio_get_scsi_ddp(scsim);
                if (dma_buf == NULL || i > scsim->max_sge) {
                        req->drv_status = -EBUSY;
                        break;
                }
                alloc_len += dma_buf->len;
                /* Added to IO req */
                list_add_tail(&dma_buf->list, &req->gen_list);
                i++;
        }

        if (!req->drv_status) {
                /* set number of ddp bufs used */
                req->nsge = i;
                csio_scsi_read(req);
                return;
        }

         /* release dma descs */
        if (i > 0)
                csio_put_scsi_ddp_list(scsim, &req->gen_list, i);
}

/*
 * csio_scsi_init_abrt_cls_wr - Initialize an ABORT/CLOSE WR.
 * @req: IO req structure.
 * @addr: DMA location to place the payload.
 * @size: Size of WR
 * @abort: abort OR close
 *
 * Wrapper for populating fw_scsi_cmd_wr.
 */
static inline void
csio_scsi_init_abrt_cls_wr(struct csio_ioreq *req, void *addr, uint32_t size,
                           bool abort)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_rnode *rn = req->rnode;
        struct fw_scsi_abrt_cls_wr *wr = (struct fw_scsi_abrt_cls_wr *)addr;

        wr->op_immdlen = cpu_to_be32(FW_WR_OP(FW_SCSI_ABRT_CLS_WR));
        wr->flowid_len16 = cpu_to_be32(FW_WR_FLOWID(rn->flowid) |
                                            FW_WR_LEN16(
                                                DIV_ROUND_UP(size, 16)));

        wr->cookie = (uintptr_t) req;
        wr->iqid = cpu_to_be16(csio_q_physiqid(hw, req->iq_idx));
        wr->tmo_val = (uint8_t) req->tmo;
        /* 0 for CHK_ALL_IO tells FW to look up t_cookie */
        wr->sub_opcode_to_chk_all_io =
                                (FW_SCSI_ABRT_CLS_WR_SUB_OPCODE(abort) |
                                 FW_SCSI_ABRT_CLS_WR_CHK_ALL_IO(0));
        wr->r3[0] = 0;
        wr->r3[1] = 0;
        wr->r3[2] = 0;
        wr->r3[3] = 0;
        /* Since we re-use the same ioreq for abort as well */
        wr->t_cookie = (uintptr_t) req;
}

static inline void
csio_scsi_abrt_cls(struct csio_ioreq *req, bool abort)
{
        struct csio_wr_pair wrp;
        struct csio_hw *hw = req->lnode->hwp;
        uint32_t size = ALIGN(sizeof(struct fw_scsi_abrt_cls_wr), 16);

        req->drv_status = csio_wr_get(hw, req->eq_idx, size, &wrp);
        if (req->drv_status != 0)
                return;

        if (wrp.size1 >= size) {
                /* Initialize WR in one shot */
                csio_scsi_init_abrt_cls_wr(req, wrp.addr1, size, abort);
        } else {
                uint8_t *tmpwr = csio_q_eq_wrap(hw, req->eq_idx);
                /*
                 * Make a temporary copy of the WR and write back
                 * the copy into the WR pair.
                 */
                csio_scsi_init_abrt_cls_wr(req, (void *)tmpwr, size, abort);
                memcpy(wrp.addr1, tmpwr, wrp.size1);
                memcpy(wrp.addr2, tmpwr + wrp.size1, size - wrp.size1);
        }
}

/*****************************************************************************/
/* START: SCSI SM                                                            */
/*****************************************************************************/
static void
csio_scsis_uninit(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);

        switch (evt) {
        case CSIO_SCSIE_START_IO:

                if (req->nsge) {
                        if (req->datadir == DMA_TO_DEVICE) {
                                req->dcopy = 0;
                                csio_scsi_write(req);
                        } else
                                csio_setup_ddp(scsim, req);
                } else {
                        csio_scsi_cmd(req);
                }

                if (likely(req->drv_status == 0)) {
                        /* change state and enqueue on active_q */
                        csio_set_state(&req->sm, csio_scsis_io_active);
                        list_add_tail(&req->sm.sm_list, &scsim->active_q);
                        csio_wr_issue(hw, req->eq_idx, false);
                        CSIO_INC_STATS(scsim, n_active);

                        return;
                }
                break;

        case CSIO_SCSIE_START_TM:
                csio_scsi_cmd(req);
                if (req->drv_status == 0) {
                        /*
                         * NOTE: We collect the affected I/Os prior to issuing
                         * LUN reset, and not after it. This is to prevent
                         * aborting I/Os that get issued after the LUN reset,
                         * but prior to LUN reset completion (in the event that
                         * the host stack has not blocked I/Os to a LUN that is
                         * being reset.
                         */
                        csio_set_state(&req->sm, csio_scsis_tm_active);
                        list_add_tail(&req->sm.sm_list, &scsim->active_q);
                        csio_wr_issue(hw, req->eq_idx, false);
                        CSIO_INC_STATS(scsim, n_tm_active);
                }
                return;

        case CSIO_SCSIE_ABORT:
        case CSIO_SCSIE_CLOSE:
                /*
                 * NOTE:
                 * We could get here due to  :
                 * - a window in the cleanup path of the SCSI module
                 *   (csio_scsi_abort_io()). Please see NOTE in this function.
                 * - a window in the time we tried to issue an abort/close
                 *   of a request to FW, and the FW completed the request
                 *   itself.
                 *   Print a message for now, and return INVAL either way.
                 */
                req->drv_status = -EINVAL;
                csio_warn(hw, "Trying to abort/close completed IO:%p!\n", req);
                break;

        default:
                csio_dbg(hw, "Unhandled event:%d sent to req:%p\n", evt, req);
                CSIO_DB_ASSERT(0);
        }
}

static void
csio_scsis_io_active(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scm = csio_hw_to_scsim(hw);
        struct csio_rnode *rn;

        switch (evt) {
        case CSIO_SCSIE_COMPLETED:
                CSIO_DEC_STATS(scm, n_active);
                list_del_init(&req->sm.sm_list);
                csio_set_state(&req->sm, csio_scsis_uninit);
                /*
                 * In MSIX mode, with multiple queues, the SCSI compeltions
                 * could reach us sooner than the FW events sent to indicate
                 * I-T nexus loss (link down, remote device logo etc). We
                 * dont want to be returning such I/Os to the upper layer
                 * immediately, since we wouldnt have reported the I-T nexus
                 * loss itself. This forces us to serialize such completions
                 * with the reporting of the I-T nexus loss. Therefore, we
                 * internally queue up such up such completions in the rnode.
                 * The reporting of I-T nexus loss to the upper layer is then
                 * followed by the returning of I/Os in this internal queue.
                 * Having another state alongwith another queue helps us take
                 * actions for events such as ABORT received while we are
                 * in this rnode queue.
                 */
                if (unlikely(req->wr_status != FW_SUCCESS)) {
                        rn = req->rnode;
                        /*
                         * FW says remote device is lost, but rnode
                         * doesnt reflect it.
                         */
                        if (csio_scsi_itnexus_loss_error(req->wr_status) &&
                                                csio_is_rnode_ready(rn)) {
                                csio_set_state(&req->sm,
                                                csio_scsis_shost_cmpl_await);
                                list_add_tail(&req->sm.sm_list,
                                              &rn->host_cmpl_q);
                        }
                }

                break;

        case CSIO_SCSIE_ABORT:
                csio_scsi_abrt_cls(req, SCSI_ABORT);
                if (req->drv_status == 0) {
                        csio_wr_issue(hw, req->eq_idx, false);
                        csio_set_state(&req->sm, csio_scsis_aborting);
                }
                break;

        case CSIO_SCSIE_CLOSE:
                csio_scsi_abrt_cls(req, SCSI_CLOSE);
                if (req->drv_status == 0) {
                        csio_wr_issue(hw, req->eq_idx, false);
                        csio_set_state(&req->sm, csio_scsis_closing);
                }
                break;

        case CSIO_SCSIE_DRVCLEANUP:
                req->wr_status = FW_HOSTERROR;
                CSIO_DEC_STATS(scm, n_active);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        default:
                csio_dbg(hw, "Unhandled event:%d sent to req:%p\n", evt, req);
                CSIO_DB_ASSERT(0);
        }
}

static void
csio_scsis_tm_active(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scm = csio_hw_to_scsim(hw);

        switch (evt) {
        case CSIO_SCSIE_COMPLETED:
                CSIO_DEC_STATS(scm, n_tm_active);
                list_del_init(&req->sm.sm_list);
                csio_set_state(&req->sm, csio_scsis_uninit);

                break;

        case CSIO_SCSIE_ABORT:
                csio_scsi_abrt_cls(req, SCSI_ABORT);
                if (req->drv_status == 0) {
                        csio_wr_issue(hw, req->eq_idx, false);
                        csio_set_state(&req->sm, csio_scsis_aborting);
                }
                break;


        case CSIO_SCSIE_CLOSE:
                csio_scsi_abrt_cls(req, SCSI_CLOSE);
                if (req->drv_status == 0) {
                        csio_wr_issue(hw, req->eq_idx, false);
                        csio_set_state(&req->sm, csio_scsis_closing);
                }
                break;

        case CSIO_SCSIE_DRVCLEANUP:
                req->wr_status = FW_HOSTERROR;
                CSIO_DEC_STATS(scm, n_tm_active);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        default:
                csio_dbg(hw, "Unhandled event:%d sent to req:%p\n", evt, req);
                CSIO_DB_ASSERT(0);
        }
}

static void
csio_scsis_aborting(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scm = csio_hw_to_scsim(hw);

        switch (evt) {
        case CSIO_SCSIE_COMPLETED:
                csio_dbg(hw,
                         "ioreq %p recvd cmpltd (wr_status:%d) "
                         "in aborting st\n", req, req->wr_status);
                /*
                 * Use -ECANCELED to explicitly tell the ABORTED event that
                 * the original I/O was returned to driver by FW.
                 * We dont really care if the I/O was returned with success by
                 * FW (because the ABORT and completion of the I/O crossed each
                 * other), or any other return value. Once we are in aborting
                 * state, the success or failure of the I/O is unimportant to
                 * us.
                 */
                req->drv_status = -ECANCELED;
                break;

        case CSIO_SCSIE_ABORT:
                CSIO_INC_STATS(scm, n_abrt_dups);
                break;

        case CSIO_SCSIE_ABORTED:

                csio_dbg(hw, "abort of %p return status:0x%x drv_status:%x\n",
                         req, req->wr_status, req->drv_status);
                /*
                 * Check if original I/O WR completed before the Abort
                 * completion.
                 */
                if (req->drv_status != -ECANCELED) {
                        csio_warn(hw,
                                  "Abort completed before original I/O,"
                                   " req:%p\n", req);
                        CSIO_DB_ASSERT(0);
                }

                /*
                 * There are the following possible scenarios:
                 * 1. The abort completed successfully, FW returned FW_SUCCESS.
                 * 2. The completion of an I/O and the receipt of
                 *    abort for that I/O by the FW crossed each other.
                 *    The FW returned FW_EINVAL. The original I/O would have
                 *    returned with FW_SUCCESS or any other SCSI error.
                 * 3. The FW couldnt sent the abort out on the wire, as there
                 *    was an I-T nexus loss (link down, remote device logged
                 *    out etc). FW sent back an appropriate IT nexus loss status
                 *    for the abort.
                 * 4. FW sent an abort, but abort timed out (remote device
                 *    didnt respond). FW replied back with
                 *    FW_SCSI_ABORT_TIMEDOUT.
                 * 5. FW couldnt genuinely abort the request for some reason,
                 *    and sent us an error.
                 *
                 * The first 3 scenarios are treated as  succesful abort
                 * operations by the host, while the last 2 are failed attempts
                 * to abort. Manipulate the return value of the request
                 * appropriately, so that host can convey these results
                 * back to the upper layer.
                 */
                if ((req->wr_status == FW_SUCCESS) ||
                    (req->wr_status == FW_EINVAL) ||
                    csio_scsi_itnexus_loss_error(req->wr_status))
                        req->wr_status = FW_SCSI_ABORT_REQUESTED;

                CSIO_DEC_STATS(scm, n_active);
                list_del_init(&req->sm.sm_list);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        case CSIO_SCSIE_DRVCLEANUP:
                req->wr_status = FW_HOSTERROR;
                CSIO_DEC_STATS(scm, n_active);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        case CSIO_SCSIE_CLOSE:
                /*
                 * We can receive this event from the module
                 * cleanup paths, if the FW forgot to reply to the ABORT WR
                 * and left this ioreq in this state. For now, just ignore
                 * the event. The CLOSE event is sent to this state, as
                 * the LINK may have already gone down.
                 */
                break;

        default:
                csio_dbg(hw, "Unhandled event:%d sent to req:%p\n", evt, req);
                CSIO_DB_ASSERT(0);
        }
}

static void
csio_scsis_closing(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        struct csio_hw *hw = req->lnode->hwp;
        struct csio_scsim *scm = csio_hw_to_scsim(hw);

        switch (evt) {
        case CSIO_SCSIE_COMPLETED:
                csio_dbg(hw,
                         "ioreq %p recvd cmpltd (wr_status:%d) "
                         "in closing st\n", req, req->wr_status);
                /*
                 * Use -ECANCELED to explicitly tell the CLOSED event that
                 * the original I/O was returned to driver by FW.
                 * We dont really care if the I/O was returned with success by
                 * FW (because the CLOSE and completion of the I/O crossed each
                 * other), or any other return value. Once we are in aborting
                 * state, the success or failure of the I/O is unimportant to
                 * us.
                 */
                req->drv_status = -ECANCELED;
                break;

        case CSIO_SCSIE_CLOSED:
                /*
                 * Check if original I/O WR completed before the Close
                 * completion.
                 */
                if (req->drv_status != -ECANCELED) {
                        csio_fatal(hw,
                                   "Close completed before original I/O,"
                                   " req:%p\n", req);
                        CSIO_DB_ASSERT(0);
                }

                /*
                 * Either close succeeded, or we issued close to FW at the
                 * same time FW compelted it to us. Either way, the I/O
                 * is closed.
                 */
                CSIO_DB_ASSERT((req->wr_status == FW_SUCCESS) ||
                                        (req->wr_status == FW_EINVAL));
                req->wr_status = FW_SCSI_CLOSE_REQUESTED;

                CSIO_DEC_STATS(scm, n_active);
                list_del_init(&req->sm.sm_list);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        case CSIO_SCSIE_CLOSE:
                break;

        case CSIO_SCSIE_DRVCLEANUP:
                req->wr_status = FW_HOSTERROR;
                CSIO_DEC_STATS(scm, n_active);
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;

        default:
                csio_dbg(hw, "Unhandled event:%d sent to req:%p\n", evt, req);
                CSIO_DB_ASSERT(0);
        }
}

static void
csio_scsis_shost_cmpl_await(struct csio_ioreq *req, enum csio_scsi_ev evt)
{
        switch (evt) {
        case CSIO_SCSIE_ABORT:
        case CSIO_SCSIE_CLOSE:
                /*
                 * Just succeed the abort request, and hope that
                 * the remote device unregister path will cleanup
                 * this I/O to the upper layer within a sane
                 * amount of time.
                 */
                /*
                 * A close can come in during a LINK DOWN. The FW would have
                 * returned us the I/O back, but not the remote device lost
                 * FW event. In this interval, if the I/O times out at the upper
                 * layer, a close can come in. Take the same action as abort:
                 * return success, and hope that the remote device unregister
                 * path will cleanup this I/O. If the FW still doesnt send
                 * the msg, the close times out, and the upper layer resorts
                 * to the next level of error recovery.
                 */
                req->drv_status = 0;
                break;
        case CSIO_SCSIE_DRVCLEANUP:
                csio_set_state(&req->sm, csio_scsis_uninit);
                break;
        default:
                csio_dbg(req->lnode->hwp, "Unhandled event:%d sent to req:%p\n",
                         evt, req);
                CSIO_DB_ASSERT(0);
        }
}

/*
 * csio_scsi_cmpl_handler - WR completion handler for SCSI.
 * @hw: HW module.
 * @wr: The completed WR from the ingress queue.
 * @len: Length of the WR.
 * @flb: Freelist buffer array.
 * @priv: Private object
 * @scsiwr: Pointer to SCSI WR.
 *
 * This is the WR completion handler called per completion from the
 * ISR. It is called with lock held. It walks past the RSS and CPL message
 * header where the actual WR is present.
 * It then gets the status, WR handle (ioreq pointer) and the len of
 * the WR, based on WR opcode. Only on a non-good status is the entire
 * WR copied into the WR cache (ioreq->fw_wr).
 * The ioreq corresponding to the WR is returned to the caller.
 * NOTE: The SCSI queue doesnt allocate a freelist today, hence
 * no freelist buffer is expected.
 */
struct csio_ioreq *
csio_scsi_cmpl_handler(struct csio_hw *hw, void *wr, uint32_t len,
                     struct csio_fl_dma_buf *flb, void *priv, uint8_t **scsiwr)
{
        struct csio_ioreq *ioreq = NULL;
        struct cpl_fw6_msg *cpl;
        uint8_t *tempwr;
        uint8_t status;
        struct csio_scsim *scm = csio_hw_to_scsim(hw);

        /* skip RSS header */
        cpl = (struct cpl_fw6_msg *)((uintptr_t)wr + sizeof(__be64));

        if (unlikely(cpl->opcode != CPL_FW6_MSG)) {
                csio_warn(hw, "Error: Invalid CPL msg %x recvd on SCSI q\n",
                          cpl->opcode);
                CSIO_INC_STATS(scm, n_inval_cplop);
                return NULL;
        }

        tempwr = (uint8_t *)(cpl->data);
        status = csio_wr_status(tempwr);
        *scsiwr = tempwr;

        if (likely((*tempwr == FW_SCSI_READ_WR) ||
                        (*tempwr == FW_SCSI_WRITE_WR) ||
                        (*tempwr == FW_SCSI_CMD_WR))) {
                ioreq = (struct csio_ioreq *)((uintptr_t)
                                 (((struct fw_scsi_read_wr *)tempwr)->cookie));
                CSIO_DB_ASSERT(virt_addr_valid(ioreq));

                ioreq->wr_status = status;

                return ioreq;
        }

        if (*tempwr == FW_SCSI_ABRT_CLS_WR) {
                ioreq = (struct csio_ioreq *)((uintptr_t)
                         (((struct fw_scsi_abrt_cls_wr *)tempwr)->cookie));
                CSIO_DB_ASSERT(virt_addr_valid(ioreq));

                ioreq->wr_status = status;
                return ioreq;
        }

        csio_warn(hw, "WR with invalid opcode in SCSI IQ: %x\n", *tempwr);
        CSIO_INC_STATS(scm, n_inval_scsiop);
        return NULL;
}

/*
 * csio_scsi_cleanup_io_q - Cleanup the given queue.
 * @scm: SCSI module.
 * @q: Queue to be cleaned up.
 *
 * Called with lock held. Has to exit with lock held.
 */
void
csio_scsi_cleanup_io_q(struct csio_scsim *scm, struct list_head *q)
{
        struct csio_hw *hw = scm->hw;
        struct csio_ioreq *ioreq;
        struct list_head *tmp, *next;
        struct scsi_cmnd *scmnd;

        /* Call back the completion routines of the active_q */
        list_for_each_safe(tmp, next, q) {
                ioreq = (struct csio_ioreq *)tmp;
                csio_scsi_drvcleanup(ioreq);
                list_del_init(&ioreq->sm.sm_list);
                scmnd = csio_scsi_cmnd(ioreq);
                spin_unlock_irq(&hw->lock);

                /*
                 * Upper layers may have cleared this command, hence this
                 * check to avoid accessing stale references.
                 */
                if (scmnd != NULL)
                        ioreq->io_cbfn(hw, ioreq);

                spin_lock_irq(&scm->freelist_lock);
                csio_put_scsi_ioreq(scm, ioreq);
                spin_unlock_irq(&scm->freelist_lock);

                spin_lock_irq(&hw->lock);
        }
}

#define CSIO_SCSI_ABORT_Q_POLL_MS               2000

static void
csio_abrt_cls(struct csio_ioreq *ioreq, struct scsi_cmnd *scmnd)
{
        struct csio_lnode *ln = ioreq->lnode;
        struct csio_hw *hw = ln->hwp;
        int ready = 0;
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);
        int rv;

        if (csio_scsi_cmnd(ioreq) != scmnd) {
                CSIO_INC_STATS(scsim, n_abrt_race_comp);
                return;
        }

        ready = csio_is_lnode_ready(ln);

        rv = csio_do_abrt_cls(hw, ioreq, (ready ? SCSI_ABORT : SCSI_CLOSE));
        if (rv != 0) {
                if (ready)
                        CSIO_INC_STATS(scsim, n_abrt_busy_error);
                else
                        CSIO_INC_STATS(scsim, n_cls_busy_error);
        }
}

/*
 * csio_scsi_abort_io_q - Abort all I/Os on given queue
 * @scm: SCSI module.
 * @q: Queue to abort.
 * @tmo: Timeout in ms
 *
 * Attempt to abort all I/Os on given queue, and wait for a max
 * of tmo milliseconds for them to complete. Returns success
 * if all I/Os are aborted. Else returns -ETIMEDOUT.
 * Should be entered with lock held. Exits with lock held.
 * NOTE:
 * Lock has to be held across the loop that aborts I/Os, since dropping the lock
 * in between can cause the list to be corrupted. As a result, the caller
 * of this function has to ensure that the number of I/os to be aborted
 * is finite enough to not cause lock-held-for-too-long issues.
 */
static int
csio_scsi_abort_io_q(struct csio_scsim *scm, struct list_head *q, uint32_t tmo)
{
        struct csio_hw *hw = scm->hw;
        struct list_head *tmp, *next;
        int count = DIV_ROUND_UP(tmo, CSIO_SCSI_ABORT_Q_POLL_MS);
        struct scsi_cmnd *scmnd;

        if (list_empty(q))
                return 0;

        csio_dbg(hw, "Aborting SCSI I/Os\n");

        /* Now abort/close I/Os in the queue passed */
        list_for_each_safe(tmp, next, q) {
                scmnd = csio_scsi_cmnd((struct csio_ioreq *)tmp);
                csio_abrt_cls((struct csio_ioreq *)tmp, scmnd);
        }

        /* Wait till all active I/Os are completed/aborted/closed */
        while (!list_empty(q) && count--) {
                spin_unlock_irq(&hw->lock);
                msleep(CSIO_SCSI_ABORT_Q_POLL_MS);
                spin_lock_irq(&hw->lock);
        }

        /* all aborts completed */
        if (list_empty(q))
                return 0;

        return -ETIMEDOUT;
}

/*
 * csio_scsim_cleanup_io - Cleanup all I/Os in SCSI module.
 * @scm: SCSI module.
 * @abort: abort required.
 * Called with lock held, should exit with lock held.
 * Can sleep when waiting for I/Os to complete.
 */
int
csio_scsim_cleanup_io(struct csio_scsim *scm, bool abort)
{
        struct csio_hw *hw = scm->hw;
        int rv = 0;
        int count = DIV_ROUND_UP(60 * 1000, CSIO_SCSI_ABORT_Q_POLL_MS);

        /* No I/Os pending */
        if (list_empty(&scm->active_q))
                return 0;

        /* Wait until all active I/Os are completed */
        while (!list_empty(&scm->active_q) && count--) {
                spin_unlock_irq(&hw->lock);
                msleep(CSIO_SCSI_ABORT_Q_POLL_MS);
                spin_lock_irq(&hw->lock);
        }

        /* all I/Os completed */
        if (list_empty(&scm->active_q))
                return 0;

        /* Else abort */
        if (abort) {
                rv = csio_scsi_abort_io_q(scm, &scm->active_q, 30000);
                if (rv == 0)
                        return rv;
                csio_dbg(hw, "Some I/O aborts timed out, cleaning up..\n");
        }

        csio_scsi_cleanup_io_q(scm, &scm->active_q);

        CSIO_DB_ASSERT(list_empty(&scm->active_q));

        return rv;
}

/*
 * csio_scsim_cleanup_io_lnode - Cleanup all I/Os of given lnode.
 * @scm: SCSI module.
 * @lnode: lnode
 *
 * Called with lock held, should exit with lock held.
 * Can sleep (with dropped lock) when waiting for I/Os to complete.
 */
int
csio_scsim_cleanup_io_lnode(struct csio_scsim *scm, struct csio_lnode *ln)
{
        struct csio_hw *hw = scm->hw;
        struct csio_scsi_level_data sld;
        int rv;
        int count = DIV_ROUND_UP(60 * 1000, CSIO_SCSI_ABORT_Q_POLL_MS);

        csio_dbg(hw, "Gathering all SCSI I/Os on lnode %p\n", ln);

        sld.level = CSIO_LEV_LNODE;
        sld.lnode = ln;
        INIT_LIST_HEAD(&ln->cmpl_q);
        csio_scsi_gather_active_ios(scm, &sld, &ln->cmpl_q);

        /* No I/Os pending on this lnode  */
        if (list_empty(&ln->cmpl_q))
                return 0;

        /* Wait until all active I/Os on this lnode are completed */
        while (!list_empty(&ln->cmpl_q) && count--) {
                spin_unlock_irq(&hw->lock);
                msleep(CSIO_SCSI_ABORT_Q_POLL_MS);
                spin_lock_irq(&hw->lock);
        }

        /* all I/Os completed */
        if (list_empty(&ln->cmpl_q))
                return 0;

        csio_dbg(hw, "Some I/Os pending on ln:%p, aborting them..\n", ln);

        /* I/Os are pending, abort them */
        rv = csio_scsi_abort_io_q(scm, &ln->cmpl_q, 30000);
        if (rv != 0) {
                csio_dbg(hw, "Some I/O aborts timed out, cleaning up..\n");
                csio_scsi_cleanup_io_q(scm, &ln->cmpl_q);
        }

        CSIO_DB_ASSERT(list_empty(&ln->cmpl_q));

        return rv;
}

static ssize_t
csio_show_hw_state(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));
        struct csio_hw *hw = csio_lnode_to_hw(ln);

        if (csio_is_hw_ready(hw))
                return snprintf(buf, PAGE_SIZE, "ready\n");
        else
                return snprintf(buf, PAGE_SIZE, "not ready\n");
}

/* Device reset */
static ssize_t
csio_device_reset(struct device *dev,
                   struct device_attribute *attr, const char *buf, size_t count)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));
        struct csio_hw *hw = csio_lnode_to_hw(ln);

        if (*buf != '1')
                return -EINVAL;

        /* Delete NPIV lnodes */
         csio_lnodes_exit(hw, 1);

        /* Block upper IOs */
        csio_lnodes_block_request(hw);

        spin_lock_irq(&hw->lock);
        csio_hw_reset(hw);
        spin_unlock_irq(&hw->lock);

        /* Unblock upper IOs */
        csio_lnodes_unblock_request(hw);
        return count;
}

/* disable port */
static ssize_t
csio_disable_port(struct device *dev,
                   struct device_attribute *attr, const char *buf, size_t count)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));
        struct csio_hw *hw = csio_lnode_to_hw(ln);
        bool disable;

        if (*buf == '1' || *buf == '0')
                disable = (*buf == '1') ? true : false;
        else
                return -EINVAL;

        /* Block upper IOs */
        csio_lnodes_block_by_port(hw, ln->portid);

        spin_lock_irq(&hw->lock);
        csio_disable_lnodes(hw, ln->portid, disable);
        spin_unlock_irq(&hw->lock);

        /* Unblock upper IOs */
        csio_lnodes_unblock_by_port(hw, ln->portid);
        return count;
}

/* Show debug level */
static ssize_t
csio_show_dbg_level(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));

        return snprintf(buf, PAGE_SIZE, "%x\n", ln->params.log_level);
}

/* Store debug level */
static ssize_t
csio_store_dbg_level(struct device *dev,
                   struct device_attribute *attr, const char *buf, size_t count)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));
        struct csio_hw *hw = csio_lnode_to_hw(ln);
        uint32_t dbg_level = 0;

        if (!isdigit(buf[0]))
                return -EINVAL;

        if (sscanf(buf, "%i", &dbg_level))
                return -EINVAL;

        ln->params.log_level = dbg_level;
        hw->params.log_level = dbg_level;

        return 0;
}

static DEVICE_ATTR(hw_state, S_IRUGO, csio_show_hw_state, NULL);
static DEVICE_ATTR(device_reset, S_IWUSR, NULL, csio_device_reset);
static DEVICE_ATTR(disable_port, S_IWUSR, NULL, csio_disable_port);
static DEVICE_ATTR(dbg_level, S_IRUGO | S_IWUSR, csio_show_dbg_level,
                  csio_store_dbg_level);

static struct device_attribute *csio_fcoe_lport_attrs[] = {
        &dev_attr_hw_state,
        &dev_attr_device_reset,
        &dev_attr_disable_port,
        &dev_attr_dbg_level,
        NULL,
};

static ssize_t
csio_show_num_reg_rnodes(struct device *dev,
                     struct device_attribute *attr, char *buf)
{
        struct csio_lnode *ln = shost_priv(class_to_shost(dev));

        return snprintf(buf, PAGE_SIZE, "%d\n", ln->num_reg_rnodes);
}

static DEVICE_ATTR(num_reg_rnodes, S_IRUGO, csio_show_num_reg_rnodes, NULL);

static struct device_attribute *csio_fcoe_vport_attrs[] = {
        &dev_attr_num_reg_rnodes,
        &dev_attr_dbg_level,
        NULL,
};

static inline uint32_t
csio_scsi_copy_to_sgl(struct csio_hw *hw, struct csio_ioreq *req)
{
        struct scsi_cmnd *scmnd  = (struct scsi_cmnd *)csio_scsi_cmnd(req);
        struct scatterlist *sg;
        uint32_t bytes_left;
        uint32_t bytes_copy;
        uint32_t buf_off = 0;
        uint32_t start_off = 0;
        uint32_t sg_off = 0;
        void *sg_addr;
        void *buf_addr;
        struct csio_dma_buf *dma_buf;

        bytes_left = scsi_bufflen(scmnd);
        sg = scsi_sglist(scmnd);
        dma_buf = (struct csio_dma_buf *)csio_list_next(&req->gen_list);

        /* Copy data from driver buffer to SGs of SCSI CMD */
        while (bytes_left > 0 && sg && dma_buf) {
                if (buf_off >= dma_buf->len) {
                        buf_off = 0;
                        dma_buf = (struct csio_dma_buf *)
                                        csio_list_next(dma_buf);
                        continue;
                }

                if (start_off >= sg->length) {
                        start_off -= sg->length;
                        sg = sg_next(sg);
                        continue;
                }

                buf_addr = dma_buf->vaddr + buf_off;
                sg_off = sg->offset + start_off;
                bytes_copy = min((dma_buf->len - buf_off),
                                sg->length - start_off);
                bytes_copy = min((uint32_t)(PAGE_SIZE - (sg_off & ~PAGE_MASK)),
                                 bytes_copy);

                sg_addr = kmap_atomic(sg_page(sg) + (sg_off >> PAGE_SHIFT));
                if (!sg_addr) {
                        csio_err(hw, "failed to kmap sg:%p of ioreq:%p\n",
                                sg, req);
                        break;
                }

                csio_dbg(hw, "copy_to_sgl:sg_addr %p sg_off %d buf %p len %d\n",
                                sg_addr, sg_off, buf_addr, bytes_copy);
                memcpy(sg_addr + (sg_off & ~PAGE_MASK), buf_addr, bytes_copy);
                kunmap_atomic(sg_addr);

                start_off +=  bytes_copy;
                buf_off += bytes_copy;
                bytes_left -= bytes_copy;
        }

        if (bytes_left > 0)
                return DID_ERROR;
        else
                return DID_OK;
}

/*
 * csio_scsi_err_handler - SCSI error handler.
 * @hw: HW module.
 * @req: IO request.
 *
 */
static inline void
csio_scsi_err_handler(struct csio_hw *hw, struct csio_ioreq *req)
{
        struct scsi_cmnd *cmnd  = (struct scsi_cmnd *)csio_scsi_cmnd(req);
        struct csio_scsim *scm = csio_hw_to_scsim(hw);
        struct fcp_resp_with_ext *fcp_resp;
        struct fcp_resp_rsp_info *rsp_info;
        struct csio_dma_buf *dma_buf;
        uint8_t flags, scsi_status = 0;
        uint32_t host_status = DID_OK;
        uint32_t rsp_len = 0, sns_len = 0;
        struct csio_rnode *rn = (struct csio_rnode *)(cmnd->device->hostdata);


        switch (req->wr_status) {
        case FW_HOSTERROR:
                if (unlikely(!csio_is_hw_ready(hw)))
                        return;

                host_status = DID_ERROR;
                CSIO_INC_STATS(scm, n_hosterror);

                break;
        case FW_SCSI_RSP_ERR:
                dma_buf = &req->dma_buf;
                fcp_resp = (struct fcp_resp_with_ext *)dma_buf->vaddr;
                rsp_info = (struct fcp_resp_rsp_info *)(fcp_resp + 1);
                flags = fcp_resp->resp.fr_flags;
                scsi_status = fcp_resp->resp.fr_status;

                if (flags & FCP_RSP_LEN_VAL) {
                        rsp_len = be32_to_cpu(fcp_resp->ext.fr_rsp_len);
                        if ((rsp_len != 0 && rsp_len != 4 && rsp_len != 8) ||
                                (rsp_info->rsp_code != FCP_TMF_CMPL)) {
                                host_status = DID_ERROR;
                                goto out;
                        }
                }

                if ((flags & FCP_SNS_LEN_VAL) && fcp_resp->ext.fr_sns_len) {
                        sns_len = be32_to_cpu(fcp_resp->ext.fr_sns_len);
                        if (sns_len > SCSI_SENSE_BUFFERSIZE)
                                sns_len = SCSI_SENSE_BUFFERSIZE;

                        memcpy(cmnd->sense_buffer,
                               &rsp_info->_fr_resvd[0] + rsp_len, sns_len);
                        CSIO_INC_STATS(scm, n_autosense);
                }

                scsi_set_resid(cmnd, 0);

                /* Under run */
                if (flags & FCP_RESID_UNDER) {
                        scsi_set_resid(cmnd,
                                       be32_to_cpu(fcp_resp->ext.fr_resid));

                        if (!(flags & FCP_SNS_LEN_VAL) &&
                            (scsi_status == SAM_STAT_GOOD) &&
                            ((scsi_bufflen(cmnd) - scsi_get_resid(cmnd))
                                                        < cmnd->underflow))
                                host_status = DID_ERROR;
                } else if (flags & FCP_RESID_OVER)
                        host_status = DID_ERROR;

                CSIO_INC_STATS(scm, n_rsperror);
                break;

        case FW_SCSI_OVER_FLOW_ERR:
                csio_warn(hw,
                          "Over-flow error,cmnd:0x%x expected len:0x%x"
                          " resid:0x%x\n", cmnd->cmnd[0],
                          scsi_bufflen(cmnd), scsi_get_resid(cmnd));
                host_status = DID_ERROR;
                CSIO_INC_STATS(scm, n_ovflerror);
                break;

        case FW_SCSI_UNDER_FLOW_ERR:
                csio_warn(hw,
                          "Under-flow error,cmnd:0x%x expected"
                          " len:0x%x resid:0x%x lun:0x%x ssn:0x%x\n",
                          cmnd->cmnd[0], scsi_bufflen(cmnd),
                          scsi_get_resid(cmnd), cmnd->device->lun,
                          rn->flowid);
                host_status = DID_ERROR;
                CSIO_INC_STATS(scm, n_unflerror);
                break;

        case FW_SCSI_ABORT_REQUESTED:
        case FW_SCSI_ABORTED:
        case FW_SCSI_CLOSE_REQUESTED:
                csio_dbg(hw, "Req %p cmd:%p op:%x %s\n", req, cmnd,
                             cmnd->cmnd[0],
                            (req->wr_status == FW_SCSI_CLOSE_REQUESTED) ?
                            "closed" : "aborted");
                /*
                 * csio_eh_abort_handler checks this value to
                 * succeed or fail the abort request.
                 */
                host_status = DID_REQUEUE;
                if (req->wr_status == FW_SCSI_CLOSE_REQUESTED)
                        CSIO_INC_STATS(scm, n_closed);
                else
                        CSIO_INC_STATS(scm, n_aborted);
                break;

        case FW_SCSI_ABORT_TIMEDOUT:
                /* FW timed out the abort itself */
                csio_dbg(hw, "FW timed out abort req:%p cmnd:%p status:%x\n",
                         req, cmnd, req->wr_status);
                host_status = DID_ERROR;
                CSIO_INC_STATS(scm, n_abrt_timedout);
                break;

        case FW_RDEV_NOT_READY:
                /*
                 * In firmware, a RDEV can get into this state
                 * temporarily, before moving into dissapeared/lost
                 * state. So, the driver should complete the request equivalent
                 * to device-disappeared!
                 */
                CSIO_INC_STATS(scm, n_rdev_nr_error);
                host_status = DID_ERROR;
                break;

        case FW_ERR_RDEV_LOST:
                CSIO_INC_STATS(scm, n_rdev_lost_error);
                host_status = DID_ERROR;
                break;

        case FW_ERR_RDEV_LOGO:
                CSIO_INC_STATS(scm, n_rdev_logo_error);
                host_status = DID_ERROR;
                break;

        case FW_ERR_RDEV_IMPL_LOGO:
                host_status = DID_ERROR;
                break;

        case FW_ERR_LINK_DOWN:
                CSIO_INC_STATS(scm, n_link_down_error);
                host_status = DID_ERROR;
                break;

        case FW_FCOE_NO_XCHG:
                CSIO_INC_STATS(scm, n_no_xchg_error);
                host_status = DID_ERROR;
                break;

        default:
                csio_err(hw, "Unknown SCSI FW WR status:%d req:%p cmnd:%p\n",
                            req->wr_status, req, cmnd);
                CSIO_DB_ASSERT(0);

                CSIO_INC_STATS(scm, n_unknown_error);
                host_status = DID_ERROR;
                break;
        }

out:
        if (req->nsge > 0)
                scsi_dma_unmap(cmnd);

        cmnd->result = (((host_status) << 16) | scsi_status);
        cmnd->scsi_done(cmnd);

        /* Wake up waiting threads */
        csio_scsi_cmnd(req) = NULL;
        complete_all(&req->cmplobj);
}

/*
 * csio_scsi_cbfn - SCSI callback function.
 * @hw: HW module.
 * @req: IO request.
 *
 */
static void
csio_scsi_cbfn(struct csio_hw *hw, struct csio_ioreq *req)
{
        struct scsi_cmnd *cmnd  = (struct scsi_cmnd *)csio_scsi_cmnd(req);
        uint8_t scsi_status = SAM_STAT_GOOD;
        uint32_t host_status = DID_OK;

        if (likely(req->wr_status == FW_SUCCESS)) {
                if (req->nsge > 0) {
                        scsi_dma_unmap(cmnd);
                        if (req->dcopy)
                                host_status = csio_scsi_copy_to_sgl(hw, req);
                }

                cmnd->result = (((host_status) << 16) | scsi_status);
                cmnd->scsi_done(cmnd);
                csio_scsi_cmnd(req) = NULL;
                CSIO_INC_STATS(csio_hw_to_scsim(hw), n_tot_success);
        } else {
                /* Error handling */
                csio_scsi_err_handler(hw, req);
        }
}

/**
 * csio_queuecommand - Entry point to kickstart an I/O request.
 * @host:       The scsi_host pointer.
 * @cmnd:       The I/O request from ML.
 *
 * This routine does the following:
 *      - Checks for HW and Rnode module readiness.
 *      - Gets a free ioreq structure (which is already initialized
 *        to uninit during its allocation).
 *      - Maps SG elements.
 *      - Initializes ioreq members.
 *      - Kicks off the SCSI state machine for this IO.
 *      - Returns busy status on error.
 */
static int
csio_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmnd)
{
        struct csio_lnode *ln = shost_priv(host);
        struct csio_hw *hw = csio_lnode_to_hw(ln);
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);
        struct csio_rnode *rn = (struct csio_rnode *)(cmnd->device->hostdata);
        struct csio_ioreq *ioreq = NULL;
        unsigned long flags;
        int nsge = 0;
        int rv = SCSI_MLQUEUE_HOST_BUSY, nr;
        int retval;
        int cpu;
        struct csio_scsi_qset *sqset;
        struct fc_rport *rport = starget_to_rport(scsi_target(cmnd->device));

        if (!blk_rq_cpu_valid(cmnd->request))
                cpu = smp_processor_id();
        else
                cpu = cmnd->request->cpu;

        sqset = &hw->sqset[ln->portid][cpu];

        nr = fc_remote_port_chkready(rport);
        if (nr) {
                cmnd->result = nr;
                CSIO_INC_STATS(scsim, n_rn_nr_error);
                goto err_done;
        }

        if (unlikely(!csio_is_hw_ready(hw))) {
                cmnd->result = (DID_REQUEUE << 16);
                CSIO_INC_STATS(scsim, n_hw_nr_error);
                goto err_done;
        }

        /* Get req->nsge, if there are SG elements to be mapped  */
        nsge = scsi_dma_map(cmnd);
        if (unlikely(nsge < 0)) {
                CSIO_INC_STATS(scsim, n_dmamap_error);
                goto err;
        }

        /* Do we support so many mappings? */
        if (unlikely(nsge > scsim->max_sge)) {
                csio_warn(hw,
                          "More SGEs than can be supported."
                          " SGEs: %d, Max SGEs: %d\n", nsge, scsim->max_sge);
                CSIO_INC_STATS(scsim, n_unsupp_sge_error);
                goto err_dma_unmap;
        }

        /* Get a free ioreq structure - SM is already set to uninit */
        ioreq = csio_get_scsi_ioreq_lock(hw, scsim);
        if (!ioreq) {
                csio_err(hw, "Out of I/O request elements. Active #:%d\n",
                         scsim->stats.n_active);
                CSIO_INC_STATS(scsim, n_no_req_error);
                goto err_dma_unmap;
        }

        ioreq->nsge             = nsge;
        ioreq->lnode            = ln;
        ioreq->rnode            = rn;
        ioreq->iq_idx           = sqset->iq_idx;
        ioreq->eq_idx           = sqset->eq_idx;
        ioreq->wr_status        = 0;
        ioreq->drv_status       = 0;
        csio_scsi_cmnd(ioreq)   = (void *)cmnd;
        ioreq->tmo              = 0;
        ioreq->datadir          = cmnd->sc_data_direction;

        if (cmnd->sc_data_direction == DMA_TO_DEVICE) {
                CSIO_INC_STATS(ln, n_output_requests);
                ln->stats.n_output_bytes += scsi_bufflen(cmnd);
        } else if (cmnd->sc_data_direction == DMA_FROM_DEVICE) {
                CSIO_INC_STATS(ln, n_input_requests);
                ln->stats.n_input_bytes += scsi_bufflen(cmnd);
        } else
                CSIO_INC_STATS(ln, n_control_requests);

        /* Set cbfn */
        ioreq->io_cbfn = csio_scsi_cbfn;

        /* Needed during abort */
        cmnd->host_scribble = (unsigned char *)ioreq;
        cmnd->SCp.Message = 0;

        /* Kick off SCSI IO SM on the ioreq */
        spin_lock_irqsave(&hw->lock, flags);
        retval = csio_scsi_start_io(ioreq);
        spin_unlock_irqrestore(&hw->lock, flags);

        if (retval != 0) {
                csio_err(hw, "ioreq: %p couldnt be started, status:%d\n",
                         ioreq, retval);
                CSIO_INC_STATS(scsim, n_busy_error);
                goto err_put_req;
        }

        return 0;

err_put_req:
        csio_put_scsi_ioreq_lock(hw, scsim, ioreq);
err_dma_unmap:
        if (nsge > 0)
                scsi_dma_unmap(cmnd);
err:
        return rv;

err_done:
        cmnd->scsi_done(cmnd);
        return 0;
}

static int
csio_do_abrt_cls(struct csio_hw *hw, struct csio_ioreq *ioreq, bool abort)
{
        int rv;
        int cpu = smp_processor_id();
        struct csio_lnode *ln = ioreq->lnode;
        struct csio_scsi_qset *sqset = &hw->sqset[ln->portid][cpu];

        ioreq->tmo = CSIO_SCSI_ABRT_TMO_MS;
        /*
         * Use current processor queue for posting the abort/close, but retain
         * the ingress queue ID of the original I/O being aborted/closed - we
         * need the abort/close completion to be received on the same queue
         * as the original I/O.
         */
        ioreq->eq_idx = sqset->eq_idx;

        if (abort == SCSI_ABORT)
                rv = csio_scsi_abort(ioreq);
        else
                rv = csio_scsi_close(ioreq);

        return rv;
}

static int
csio_eh_abort_handler(struct scsi_cmnd *cmnd)
{
        struct csio_ioreq *ioreq;
        struct csio_lnode *ln = shost_priv(cmnd->device->host);
        struct csio_hw *hw = csio_lnode_to_hw(ln);
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);
        int ready = 0, ret;
        unsigned long tmo = 0;
        int rv;
        struct csio_rnode *rn = (struct csio_rnode *)(cmnd->device->hostdata);

        ret = fc_block_scsi_eh(cmnd);
        if (ret)
                return ret;

        ioreq = (struct csio_ioreq *)cmnd->host_scribble;
        if (!ioreq)
                return SUCCESS;

        if (!rn)
                return FAILED;

        csio_dbg(hw,
                 "Request to abort ioreq:%p cmd:%p cdb:%08llx"
                 " ssni:0x%x lun:%d iq:0x%x\n",
                ioreq, cmnd, *((uint64_t *)cmnd->cmnd), rn->flowid,
                cmnd->device->lun, csio_q_physiqid(hw, ioreq->iq_idx));

        if (((struct scsi_cmnd *)csio_scsi_cmnd(ioreq)) != cmnd) {
                CSIO_INC_STATS(scsim, n_abrt_race_comp);
                return SUCCESS;
        }

        ready = csio_is_lnode_ready(ln);
        tmo = CSIO_SCSI_ABRT_TMO_MS;

        spin_lock_irq(&hw->lock);
        rv = csio_do_abrt_cls(hw, ioreq, (ready ? SCSI_ABORT : SCSI_CLOSE));
        spin_unlock_irq(&hw->lock);

        if (rv != 0) {
                if (rv == -EINVAL) {
                        /* Return success, if abort/close request issued on
                         * already completed IO
                         */
                        return SUCCESS;
                }
                if (ready)
                        CSIO_INC_STATS(scsim, n_abrt_busy_error);
                else
                        CSIO_INC_STATS(scsim, n_cls_busy_error);

                goto inval_scmnd;
        }

        /* Wait for completion */
        init_completion(&ioreq->cmplobj);
        wait_for_completion_timeout(&ioreq->cmplobj, msecs_to_jiffies(tmo));

        /* FW didnt respond to abort within our timeout */
        if (((struct scsi_cmnd *)csio_scsi_cmnd(ioreq)) == cmnd) {

                csio_err(hw, "Abort timed out -- req: %p\n", ioreq);
                CSIO_INC_STATS(scsim, n_abrt_timedout);

inval_scmnd:
                if (ioreq->nsge > 0)
                        scsi_dma_unmap(cmnd);

                spin_lock_irq(&hw->lock);
                csio_scsi_cmnd(ioreq) = NULL;
                spin_unlock_irq(&hw->lock);

                cmnd->result = (DID_ERROR << 16);
                cmnd->scsi_done(cmnd);

                return FAILED;
        }

        /* FW successfully aborted the request */
        if (host_byte(cmnd->result) == DID_REQUEUE) {
                csio_info(hw,
                        "Aborted SCSI command to (%d:%d) serial#:0x%lx\n",
                        cmnd->device->id, cmnd->device->lun,
                        cmnd->serial_number);
                return SUCCESS;
        } else {
                csio_info(hw,
                        "Failed to abort SCSI command, (%d:%d) serial#:0x%lx\n",
                        cmnd->device->id, cmnd->device->lun,
                        cmnd->serial_number);
                return FAILED;
        }
}

/*
 * csio_tm_cbfn - TM callback function.
 * @hw: HW module.
 * @req: IO request.
 *
 * Cache the result in 'cmnd', since ioreq will be freed soon
 * after we return from here, and the waiting thread shouldnt trust
 * the ioreq contents.
 */
static void
csio_tm_cbfn(struct csio_hw *hw, struct csio_ioreq *req)
{
        struct scsi_cmnd *cmnd  = (struct scsi_cmnd *)csio_scsi_cmnd(req);
        struct csio_dma_buf *dma_buf;
        uint8_t flags = 0;
        struct fcp_resp_with_ext *fcp_resp;
        struct fcp_resp_rsp_info *rsp_info;

        csio_dbg(hw, "req: %p in csio_tm_cbfn status: %d\n",
                      req, req->wr_status);

        /* Cache FW return status */
        cmnd->SCp.Status = req->wr_status;

        /* Special handling based on FCP response */

        /*
         * FW returns us this error, if flags were set. FCP4 says
         * FCP_RSP_LEN_VAL in flags shall be set for TM completions.
         * So if a target were to set this bit, we expect that the
         * rsp_code is set to FCP_TMF_CMPL for a successful TM
         * completion. Any other rsp_code means TM operation failed.
         * If a target were to just ignore setting flags, we treat
         * the TM operation as success, and FW returns FW_SUCCESS.
         */
        if (req->wr_status == FW_SCSI_RSP_ERR) {
                dma_buf = &req->dma_buf;
                fcp_resp = (struct fcp_resp_with_ext *)dma_buf->vaddr;
                rsp_info = (struct fcp_resp_rsp_info *)(fcp_resp + 1);

                flags = fcp_resp->resp.fr_flags;

                /* Modify return status if flags indicate success */
                if (flags & FCP_RSP_LEN_VAL)
                        if (rsp_info->rsp_code == FCP_TMF_CMPL)
                                cmnd->SCp.Status = FW_SUCCESS;

                csio_dbg(hw, "TM FCP rsp code: %d\n", rsp_info->rsp_code);
        }

        /* Wake up the TM handler thread */
        csio_scsi_cmnd(req) = NULL;
}

static int
csio_eh_lun_reset_handler(struct scsi_cmnd *cmnd)
{
        struct csio_lnode *ln = shost_priv(cmnd->device->host);
        struct csio_hw *hw = csio_lnode_to_hw(ln);
        struct csio_scsim *scsim = csio_hw_to_scsim(hw);
        struct csio_rnode *rn = (struct csio_rnode *)(cmnd->device->hostdata);
        struct csio_ioreq *ioreq = NULL;
        struct csio_scsi_qset *sqset;
        unsigned long flags;
        int retval;
        int count, ret;
        LIST_HEAD(local_q);
        struct csio_scsi_level_data sld;

        if (!rn)
                goto fail;

        csio_dbg(hw, "Request to reset LUN:%d (ssni:0x%x tgtid:%d)\n",
                      cmnd->device->lun, rn->flowid, rn->scsi_id);

        if (!csio_is_lnode_ready(ln)) {
                csio_err(hw,
                         "LUN reset cannot be issued on non-ready"
                         " local node vnpi:0x%x (LUN:%d)\n",
                         ln->vnp_flowid, cmnd->device->lun);
                goto fail;
        }

        /* Lnode is ready, now wait on rport node readiness */
        ret = fc_block_scsi_eh(cmnd);
        if (ret)
                return ret;

        /*
         * If we have blocked in the previous call, at this point, either the
         * remote node has come back online, or device loss timer has fired
         * and the remote node is destroyed. Allow the LUN reset only for
         * the former case, since LUN reset is a TMF I/O on the wire, and we
         * need a valid session to issue it.
         */
        if (fc_remote_port_chkready(rn->rport)) {
                csio_err(hw,
                         "LUN reset cannot be issued on non-ready"
                         " remote node ssni:0x%x (LUN:%d)\n",
                         rn->flowid, cmnd->device->lun);
                goto fail;
        }

        /* Get a free ioreq structure - SM is already set to uninit */
        ioreq = csio_get_scsi_ioreq_lock(hw, scsim);

        if (!ioreq) {
                csio_err(hw, "Out of IO request elements. Active # :%d\n",
                         scsim->stats.n_active);
                goto fail;
        }

        sqset                   = &hw->sqset[ln->portid][smp_processor_id()];
        ioreq->nsge             = 0;
        ioreq->lnode            = ln;
        ioreq->rnode            = rn;
        ioreq->iq_idx           = sqset->iq_idx;
        ioreq->eq_idx           = sqset->eq_idx;

        csio_scsi_cmnd(ioreq)   = cmnd;
        cmnd->host_scribble     = (unsigned char *)ioreq;
        cmnd->SCp.Status        = 0;

        cmnd->SCp.Message       = FCP_TMF_LUN_RESET;
        ioreq->tmo              = CSIO_SCSI_LUNRST_TMO_MS / 1000;

        /*
         * FW times the LUN reset for ioreq->tmo, so we got to wait a little
         * longer (10s for now) than that to allow FW to return the timed
         * out command.
         */
        count = DIV_ROUND_UP((ioreq->tmo + 10) * 1000, CSIO_SCSI_TM_POLL_MS);

        /* Set cbfn */
        ioreq->io_cbfn = csio_tm_cbfn;

        /* Save of the ioreq info for later use */
        sld.level = CSIO_LEV_LUN;
        sld.lnode = ioreq->lnode;
        sld.rnode = ioreq->rnode;
        sld.oslun = (uint64_t)cmnd->device->lun;

        spin_lock_irqsave(&hw->lock, flags);
        /* Kick off TM SM on the ioreq */
        retval = csio_scsi_start_tm(ioreq);
        spin_unlock_irqrestore(&hw->lock, flags);

        if (retval != 0) {
                csio_err(hw, "Failed to issue LUN reset, req:%p, status:%d\n",
                            ioreq, retval);
                goto fail_ret_ioreq;
        }

        csio_dbg(hw, "Waiting max %d secs for LUN reset completion\n",
                    count * (CSIO_SCSI_TM_POLL_MS / 1000));
        /* Wait for completion */
        while ((((struct scsi_cmnd *)csio_scsi_cmnd(ioreq)) == cmnd)
                                                                && count--)
                msleep(CSIO_SCSI_TM_POLL_MS);

        /* LUN reset timed-out */
        if (((struct scsi_cmnd *)csio_scsi_cmnd(ioreq)) == cmnd) {
                csio_err(hw, "LUN reset (%d:%d) timed out\n",
                         cmnd->device->id, cmnd->device->lun);

                spin_lock_irq(&hw->lock);
                csio_scsi_drvcleanup(ioreq);
                list_del_init(&ioreq->sm.sm_list);
                spin_unlock_irq(&hw->lock);

                goto fail_ret_ioreq;
        }

        /* LUN reset returned, check cached status */
        if (cmnd->SCp.Status != FW_SUCCESS) {
                csio_err(hw, "LUN reset failed (%d:%d), status: %d\n",
                         cmnd->device->id, cmnd->device->lun, cmnd->SCp.Status);
                goto fail;
        }

        /* LUN reset succeeded, Start aborting affected I/Os */
        /*
         * Since the host guarantees during LUN reset that there
         * will not be any more I/Os to that LUN, until the LUN reset
         * completes, we gather pending I/Os after the LUN reset.
         */
        spin_lock_irq(&hw->lock);
        csio_scsi_gather_active_ios(scsim, &sld, &local_q);

        retval = csio_scsi_abort_io_q(scsim, &local_q, 30000);
        spin_unlock_irq(&hw->lock);

        /* Aborts may have timed out */
        if (retval != 0) {
                csio_err(hw,
                         "Attempt to abort I/Os during LUN reset of %d"
                         " returned %d\n", cmnd->device->lun, retval);
                /* Return I/Os back to active_q */
                spin_lock_irq(&hw->lock);
                list_splice_tail_init(&local_q, &scsim->active_q);
                spin_unlock_irq(&hw->lock);
                goto fail;
        }

        CSIO_INC_STATS(rn, n_lun_rst);

        csio_info(hw, "LUN reset occurred (%d:%d)\n",
                  cmnd->device->id, cmnd->device->lun);

        return SUCCESS;

fail_ret_ioreq:
        csio_put_scsi_ioreq_lock(hw, scsim, ioreq);
fail:
        CSIO_INC_STATS(rn, n_lun_rst_fail);
        return FAILED;
}

static int
csio_slave_alloc(struct scsi_device *sdev)
{
        struct fc_rport *rport = starget_to_rport(scsi_target(sdev));

        if (!rport || fc_remote_port_chkready(rport))
                return -ENXIO;

        sdev->hostdata = *((struct csio_lnode **)(rport->dd_data));

        return 0;
}

static int
csio_slave_configure(struct scsi_device *sdev)
{
        if (sdev->tagged_supported)
                scsi_activate_tcq(sdev, csio_lun_qdepth);
        else
                scsi_deactivate_tcq(sdev, csio_lun_qdepth);

        return 0;
}

static void
csio_slave_destroy(struct scsi_device *sdev)
{
        sdev->hostdata = NULL;
}

static int
csio_scan_finished(struct Scsi_Host *shost, unsigned long time)
{
        struct csio_lnode *ln = shost_priv(shost);
        int rv = 1;

        spin_lock_irq(shost->host_lock);
        if (!ln->hwp || csio_list_deleted(&ln->sm.sm_list))
                goto out;

        rv = csio_scan_done(ln, jiffies, time, csio_max_scan_tmo * HZ,
                            csio_delta_scan_tmo * HZ);
out:
        spin_unlock_irq(shost->host_lock);

        return rv;
}

struct scsi_host_template csio_fcoe_shost_template = {
        .module                 = THIS_MODULE,
        .name                   = CSIO_DRV_DESC,
        .proc_name              = KBUILD_MODNAME,
        .queuecommand           = csio_queuecommand,
        .eh_abort_handler       = csio_eh_abort_handler,
        .eh_device_reset_handler = csio_eh_lun_reset_handler,
        .slave_alloc            = csio_slave_alloc,
        .slave_configure        = csio_slave_configure,
        .slave_destroy          = csio_slave_destroy,
        .scan_finished          = csio_scan_finished,
        .this_id                = -1,
        .sg_tablesize           = CSIO_SCSI_MAX_SGE,
        .cmd_per_lun            = CSIO_MAX_CMD_PER_LUN,
        .use_clustering         = ENABLE_CLUSTERING,
        .shost_attrs            = csio_fcoe_lport_attrs,
        .max_sectors            = CSIO_MAX_SECTOR_SIZE,
};

struct scsi_host_template csio_fcoe_shost_vport_template = {
        .module                 = THIS_MODULE,
        .name                   = CSIO_DRV_DESC,
        .proc_name              = KBUILD_MODNAME,
        .queuecommand           = csio_queuecommand,
        .eh_abort_handler       = csio_eh_abort_handler,
        .eh_device_reset_handler = csio_eh_lun_reset_handler,
        .slave_alloc            = csio_slave_alloc,
        .slave_configure        = csio_slave_configure,
        .slave_destroy          = csio_slave_destroy,
        .scan_finished          = csio_scan_finished,
        .this_id                = -1,
        .sg_tablesize           = CSIO_SCSI_MAX_SGE,
        .cmd_per_lun            = CSIO_MAX_CMD_PER_LUN,
        .use_clustering         = ENABLE_CLUSTERING,
        .shost_attrs            = csio_fcoe_vport_attrs,
        .max_sectors            = CSIO_MAX_SECTOR_SIZE,
};

/*
 * csio_scsi_alloc_ddp_bufs - Allocate buffers for DDP of unaligned SGLs.
 * @scm: SCSI Module
 * @hw: HW device.
 * @buf_size: buffer size
 * @num_buf : Number of buffers.
 *
 * This routine allocates DMA buffers required for SCSI Data xfer, if
 * each SGL buffer for a SCSI Read request posted by SCSI midlayer are
 * not virtually contiguous.
 */
static int
csio_scsi_alloc_ddp_bufs(struct csio_scsim *scm, struct csio_hw *hw,
                         int buf_size, int num_buf)
{
        int n = 0;
        struct list_head *tmp;
        struct csio_dma_buf *ddp_desc = NULL;
        uint32_t unit_size = 0;

        if (!num_buf)
                return 0;

        if (!buf_size)
                return -EINVAL;

        INIT_LIST_HEAD(&scm->ddp_freelist);

        /* Align buf size to page size */
        buf_size = (buf_size + PAGE_SIZE - 1) & PAGE_MASK;
        /* Initialize dma descriptors */
        for (n = 0; n < num_buf; n++) {
                /* Set unit size to request size */
                unit_size = buf_size;
                ddp_desc = kzalloc(sizeof(struct csio_dma_buf), GFP_KERNEL);
                if (!ddp_desc) {
                        csio_err(hw,
                                 "Failed to allocate ddp descriptors,"
                                 " Num allocated = %d.\n",
                                 scm->stats.n_free_ddp);
                        goto no_mem;
                }

                /* Allocate Dma buffers for DDP */
                ddp_desc->vaddr = pci_alloc_consistent(hw->pdev, unit_size,
                                                        &ddp_desc->paddr);
                if (!ddp_desc->vaddr) {
                        csio_err(hw,
                                 "SCSI response DMA buffer (ddp) allocation"
                                 " failed!\n");
                        kfree(ddp_desc);
                        goto no_mem;
                }

                ddp_desc->len = unit_size;

                /* Added it to scsi ddp freelist */
                list_add_tail(&ddp_desc->list, &scm->ddp_freelist);
                CSIO_INC_STATS(scm, n_free_ddp);
        }

        return 0;
no_mem:
        /* release dma descs back to freelist and free dma memory */
        list_for_each(tmp, &scm->ddp_freelist) {
                ddp_desc = (struct csio_dma_buf *) tmp;
                tmp = csio_list_prev(tmp);
                pci_free_consistent(hw->pdev, ddp_desc->len, ddp_desc->vaddr,
                                    ddp_desc->paddr);
                list_del_init(&ddp_desc->list);
                kfree(ddp_desc);
        }
        scm->stats.n_free_ddp = 0;

        return -ENOMEM;
}

/*
 * csio_scsi_free_ddp_bufs - free DDP buffers of unaligned SGLs.
 * @scm: SCSI Module
 * @hw: HW device.
 *
 * This routine frees ddp buffers.
 */
static void
csio_scsi_free_ddp_bufs(struct csio_scsim *scm, struct csio_hw *hw)
{
        struct list_head *tmp;
        struct csio_dma_buf *ddp_desc;

        /* release dma descs back to freelist and free dma memory */
        list_for_each(tmp, &scm->ddp_freelist) {
                ddp_desc = (struct csio_dma_buf *) tmp;
                tmp = csio_list_prev(tmp);
                pci_free_consistent(hw->pdev, ddp_desc->len, ddp_desc->vaddr,
                                    ddp_desc->paddr);
                list_del_init(&ddp_desc->list);
                kfree(ddp_desc);
        }
        scm->stats.n_free_ddp = 0;
}

/**
 * csio_scsim_init - Initialize SCSI Module
 * @scm:        SCSI Module
 * @hw:         HW module
 *
 */
int
csio_scsim_init(struct csio_scsim *scm, struct csio_hw *hw)
{
        int i;
        struct csio_ioreq *ioreq;
        struct csio_dma_buf *dma_buf;

        INIT_LIST_HEAD(&scm->active_q);
        scm->hw = hw;

        scm->proto_cmd_len = sizeof(struct fcp_cmnd);
        scm->proto_rsp_len = CSIO_SCSI_RSP_LEN;
        scm->max_sge = CSIO_SCSI_MAX_SGE;

        spin_lock_init(&scm->freelist_lock);

        /* Pre-allocate ioreqs and initialize them */
        INIT_LIST_HEAD(&scm->ioreq_freelist);
        for (i = 0; i < csio_scsi_ioreqs; i++) {

                ioreq = kzalloc(sizeof(struct csio_ioreq), GFP_KERNEL);
                if (!ioreq) {
                        csio_err(hw,
                                 "I/O request element allocation failed, "
                                 " Num allocated = %d.\n",
                                 scm->stats.n_free_ioreq);

                        goto free_ioreq;
                }

                /* Allocate Dma buffers for Response Payload */
                dma_buf = &ioreq->dma_buf;
                dma_buf->vaddr = pci_pool_alloc(hw->scsi_pci_pool, GFP_KERNEL,
                                                &dma_buf->paddr);
                if (!dma_buf->vaddr) {
                        csio_err(hw,
                                 "SCSI response DMA buffer allocation"
                                 " failed!\n");
                        kfree(ioreq);
                        goto free_ioreq;
                }

                dma_buf->len = scm->proto_rsp_len;

                /* Set state to uninit */
                csio_init_state(&ioreq->sm, csio_scsis_uninit);
                INIT_LIST_HEAD(&ioreq->gen_list);
                init_completion(&ioreq->cmplobj);

                list_add_tail(&ioreq->sm.sm_list, &scm->ioreq_freelist);
                CSIO_INC_STATS(scm, n_free_ioreq);
        }

        if (csio_scsi_alloc_ddp_bufs(scm, hw, PAGE_SIZE, csio_ddp_descs))
                goto free_ioreq;

        return 0;

free_ioreq:
        /*
         * Free up existing allocations, since an error
         * from here means we are returning for good
         */
        while (!list_empty(&scm->ioreq_freelist)) {
                struct csio_sm *tmp;

                tmp = list_first_entry(&scm->ioreq_freelist,
                                       struct csio_sm, sm_list);
                list_del_init(&tmp->sm_list);
                ioreq = (struct csio_ioreq *)tmp;

                dma_buf = &ioreq->dma_buf;
                pci_pool_free(hw->scsi_pci_pool, dma_buf->vaddr,
                              dma_buf->paddr);

                kfree(ioreq);
        }

        scm->stats.n_free_ioreq = 0;

        return -ENOMEM;
}

/**
 * csio_scsim_exit: Uninitialize SCSI Module
 * @scm: SCSI Module
 *
 */
void
csio_scsim_exit(struct csio_scsim *scm)
{
        struct csio_ioreq *ioreq;
        struct csio_dma_buf *dma_buf;

        while (!list_empty(&scm->ioreq_freelist)) {
                struct csio_sm *tmp;

                tmp = list_first_entry(&scm->ioreq_freelist,
                                       struct csio_sm, sm_list);
                list_del_init(&tmp->sm_list);
                ioreq = (struct csio_ioreq *)tmp;

                dma_buf = &ioreq->dma_buf;
                pci_pool_free(scm->hw->scsi_pci_pool, dma_buf->vaddr,
                              dma_buf->paddr);

                kfree(ioreq);
        }

        scm->stats.n_free_ioreq = 0;

        csio_scsi_free_ddp_bufs(scm, scm->hw);
}