transport.c

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/slab.h>

#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_device.h>

#include "usb.h"
#include "scsiglue.h"
#include "transport.h"

/***********************************************************************
 * Data transfer routines
 ***********************************************************************/
/*
 * usb_stor_blocking_completion()
 */
static void usb_stor_blocking_completion(struct urb *urb)
{
    struct completion *urb_done_ptr = urb->context;

    /* pr_info("transport --- usb_stor_blocking_completion\n"); */
    complete(urb_done_ptr);
}

/*
 * usb_stor_msg_common()
 */
static int usb_stor_msg_common(struct us_data *us, int timeout)
{
    struct completion urb_done;
    long timeleft;
    int status;

    /* pr_info("transport --- usb_stor_msg_common\n"); */
    if (test_bit(US_FLIDX_ABORTING, &us->dflags))
        return -EIO;

    init_completion(&urb_done);

    us->current_urb->context = &urb_done;
    us->current_urb->actual_length = 0;
    us->current_urb->error_count = 0;
    us->current_urb->status = 0;

    us->current_urb->transfer_flags = 0;
    if (us->current_urb->transfer_buffer == us->iobuf)
        us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
    us->current_urb->transfer_dma = us->iobuf_dma;
    us->current_urb->setup_dma = us->cr_dma;

    status = usb_submit_urb(us->current_urb, GFP_NOIO);
    if (status)
        return status;

    set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);

    if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
        if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
            /* pr_info("-- cancelling URB\n"); */
            usb_unlink_urb(us->current_urb);
        }
    }

    timeleft = wait_for_completion_interruptible_timeout(&urb_done,
                    timeout ? : MAX_SCHEDULE_TIMEOUT);
    clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);

    if (timeleft <= 0) {
        /* pr_info("%s -- cancelling URB\n",
            timeleft == 0 ? "Timeout" : "Signal"); */
        usb_kill_urb(us->current_urb);
    }

    return us->current_urb->status;
}

/*
 * usb_stor_control_msg()
 */
int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
         u8 request, u8 requesttype, u16 value, u16 index,
         void *data, u16 size, int timeout)
{
    int status;

    /* pr_info("transport --- usb_stor_control_msg\n"); */

    /* fill in the devrequest structure */
    us->cr->bRequestType = requesttype;
    us->cr->bRequest = request;
    us->cr->wValue = cpu_to_le16(value);
    us->cr->wIndex = cpu_to_le16(index);
    us->cr->wLength = cpu_to_le16(size);

    /* fill and submit the URB */
    usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
             (unsigned char *) us->cr, data, size,
             usb_stor_blocking_completion, NULL);
    status = usb_stor_msg_common(us, timeout);

    /* return the actual length of the data transferred if no error */
    if (status == 0)
        status = us->current_urb->actual_length;
    return status;
}

/*
 * usb_stor_clear_halt()
 */
int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
{
    int result;
    int endp = usb_pipeendpoint(pipe);

    /* pr_info("transport --- usb_stor_clear_halt\n"); */
    if (usb_pipein(pipe))
        endp |= USB_DIR_IN;

    result = usb_stor_control_msg(us, us->send_ctrl_pipe,
        USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
        USB_ENDPOINT_HALT, endp,
        NULL, 0, 3*HZ);

    /* reset the endpoint toggle */
    if (result >= 0)
        /* usb_settoggle(us->pusb_dev, usb_pipeendpoint(pipe),
                        usb_pipeout(pipe), 0); */
        usb_reset_endpoint(us->pusb_dev, endp);

    return result;
}

/*
 * interpret_urb_result()
 */
static int interpret_urb_result(struct us_data *us, unsigned int pipe,
        unsigned int length, int result, unsigned int partial)
{
    /* pr_info("transport --- interpret_urb_result\n"); */
    switch (result) {
    /* no error code; did we send all the data? */
    case 0:
        if (partial != length) {
            /* pr_info("-- short transfer\n"); */
            return USB_STOR_XFER_SHORT;
        }
        /* pr_info("-- transfer complete\n"); */
        return USB_STOR_XFER_GOOD;
    case -EPIPE:
        if (usb_pipecontrol(pipe)) {
            /* pr_info("-- stall on control pipe\n"); */
            return USB_STOR_XFER_STALLED;
        }
        /* pr_info("clearing endpoint halt for pipe 0x%x\n", pipe); */
        if (usb_stor_clear_halt(us, pipe) < 0)
            return USB_STOR_XFER_ERROR;
        return USB_STOR_XFER_STALLED;
    case -EOVERFLOW:
        /* pr_info("-- babble\n"); */
        return USB_STOR_XFER_LONG;
    case -ECONNRESET:
        /* pr_info("-- transfer cancelled\n"); */
        return USB_STOR_XFER_ERROR;
    case -EREMOTEIO:
        /* pr_info("-- short read transfer\n"); */
        return USB_STOR_XFER_SHORT;
    case -EIO:
        /* pr_info("-- abort or disconnect in progress\n"); */
        return USB_STOR_XFER_ERROR;
    default:
        /* pr_info("-- unknown error\n"); */
        return USB_STOR_XFER_ERROR;
    }
}

/*
 * usb_stor_bulk_transfer_buf()
 */
int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
    void *buf, unsigned int length, unsigned int *act_len)
{
    int result;

    /* pr_info("transport --- usb_stor_bulk_transfer_buf\n"); */

    /* fill and submit the URB */
    usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf,
                length, usb_stor_blocking_completion, NULL);
    result = usb_stor_msg_common(us, 0);

    /* store the actual length of the data transferred */
    if (act_len)
        *act_len = us->current_urb->actual_length;

    return interpret_urb_result(us, pipe, length, result,
                    us->current_urb->actual_length);
}

/*
 * usb_stor_bulk_transfer_sglist()
 */
static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
        struct scatterlist *sg, int num_sg, unsigned int length,
        unsigned int *act_len)
{
    int result;

    /* pr_info("transport --- usb_stor_bulk_transfer_sglist\n"); */
    if (test_bit(US_FLIDX_ABORTING, &us->dflags))
        return USB_STOR_XFER_ERROR;

    /* initialize the scatter-gather request block */
    result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
                    sg, num_sg, length, GFP_NOIO);
    if (result) {
        /* pr_info("usb_sg_init returned %d\n", result); */
        return USB_STOR_XFER_ERROR;
    }

    /* since the block has been initialized successfully,
                    it's now okay to cancel it */
    set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);

    /* did an abort/disconnect occur during the submission? */
    if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
        /* cancel the request, if it hasn't been cancelled already */
        if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
            /* pr_info("-- cancelling sg request\n"); */
            usb_sg_cancel(&us->current_sg);
        }
    }

    /* wait for the completion of the transfer */
    usb_sg_wait(&us->current_sg);
    clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);

    result = us->current_sg.status;
    if (act_len)
        *act_len = us->current_sg.bytes;

    return interpret_urb_result(us, pipe, length,
                    result, us->current_sg.bytes);
}

/*
 * usb_stor_bulk_srb()
 */
int usb_stor_bulk_srb(struct us_data *us, unsigned int pipe,
                    struct scsi_cmnd *srb)
{
    unsigned int partial;
    int result = usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
                      scsi_sg_count(srb), scsi_bufflen(srb),
                      &partial);

    scsi_set_resid(srb, scsi_bufflen(srb) - partial);
    return result;
}

/*
 * usb_stor_bulk_transfer_sg()
 */
int usb_stor_bulk_transfer_sg(struct us_data *us, unsigned int pipe,
        void *buf, unsigned int length_left, int use_sg, int *residual)
{
    int result;
    unsigned int partial;

    /* pr_info("transport --- usb_stor_bulk_transfer_sg\n"); */
    /* are we scatter-gathering? */
    if (use_sg) {
        /* use the usb core scatter-gather primitives */
        result = usb_stor_bulk_transfer_sglist(us, pipe,
                (struct scatterlist *) buf, use_sg,
                length_left, &partial);
        length_left -= partial;
    } else {
        /* no scatter-gather, just make the request */
        result = usb_stor_bulk_transfer_buf(us, pipe, buf,
                            length_left, &partial);
        length_left -= partial;
    }

    /* store the residual and return the error code */
    if (residual)
        *residual = length_left;
    return result;
}

/***********************************************************************
 * Transport routines
 ***********************************************************************/
/*
 * usb_stor_invoke_transport()
 */
void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
{
    int need_auto_sense;
    int result;

    /* pr_info("transport --- usb_stor_invoke_transport\n"); */
    usb_stor_print_cmd(srb);
    /* send the command to the transport layer */
    scsi_set_resid(srb, 0);
    result = us->transport(srb, us); /* usb_stor_Bulk_transport; */

    /* if the command gets aborted by the higher layers,
        we need to short-circuit all other processing */
    if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
        /* pr_info("-- command was aborted\n"); */
        srb->result = DID_ABORT << 16;
        goto Handle_Errors;
    }

    /* if there is a transport error, reset and don't auto-sense */
    if (result == USB_STOR_TRANSPORT_ERROR) {
        /* pr_info("-- transport indicates error, resetting\n"); */
        srb->result = DID_ERROR << 16;
        goto Handle_Errors;
    }

    /* if the transport provided its own sense data, don't auto-sense */
    if (result == USB_STOR_TRANSPORT_NO_SENSE) {
        srb->result = SAM_STAT_CHECK_CONDITION;
        return;
    }

    srb->result = SAM_STAT_GOOD;

    /* Determine if we need to auto-sense */
    need_auto_sense = 0;

    if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
                srb->sc_data_direction != DMA_FROM_DEVICE) {
        /* pr_info("-- CB transport device requiring auto-sense\n"); */
        need_auto_sense = 1;
    }

    if (result == USB_STOR_TRANSPORT_FAILED) {
        /* pr_info("-- transport indicates command failure\n"); */
        need_auto_sense = 1;
    }

    /* Now, if we need to do the auto-sense, let's do it */
    if (need_auto_sense) {
        int temp_result;
        struct scsi_eh_save ses;

        pr_info("Issuing auto-REQUEST_SENSE\n");

        scsi_eh_prep_cmnd(srb, &ses, NULL, 0, US_SENSE_SIZE);

        /* we must do the protocol translation here */
        if (us->subclass == USB_SC_RBC ||
            us->subclass == USB_SC_SCSI ||
            us->subclass == USB_SC_CYP_ATACB) {
            srb->cmd_len = 6;
        } else {
            srb->cmd_len = 12;
        }
        /* issue the auto-sense command */
        scsi_set_resid(srb, 0);
        temp_result = us->transport(us->srb, us);

        /* let's clean up right away */
        scsi_eh_restore_cmnd(srb, &ses);

        if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
            /* pr_info("-- auto-sense aborted\n"); */
            srb->result = DID_ABORT << 16;
            goto Handle_Errors;
        }
        if (temp_result != USB_STOR_TRANSPORT_GOOD) {
            /* pr_info("-- auto-sense failure\n"); */
            srb->result = DID_ERROR << 16;
            if (!(us->fflags & US_FL_SCM_MULT_TARG))
                goto Handle_Errors;
            return;
        }

        /* set the result so the higher layers expect this data */
        srb->result = SAM_STAT_CHECK_CONDITION;

        if (result == USB_STOR_TRANSPORT_GOOD &&
            (srb->sense_buffer[2] & 0xaf) == 0 &&
            srb->sense_buffer[12] == 0 &&
            srb->sense_buffer[13] == 0) {
            srb->result = SAM_STAT_GOOD;
            srb->sense_buffer[0] = 0x0;
        }
    }

    /* Did we transfer less than the minimum amount required? */
    if (srb->result == SAM_STAT_GOOD && scsi_bufflen(srb) -
                scsi_get_resid(srb) < srb->underflow)
        srb->result = (DID_ERROR << 16);
        /* v02 | (SUGGEST_RETRY << 24); */

    return;

Handle_Errors:
    scsi_lock(us_to_host(us));
    set_bit(US_FLIDX_RESETTING, &us->dflags);
    clear_bit(US_FLIDX_ABORTING, &us->dflags);
    scsi_unlock(us_to_host(us));

    mutex_unlock(&us->dev_mutex);
    result = usb_stor_port_reset(us);
    mutex_lock(&us->dev_mutex);

    if (result < 0) {
        scsi_lock(us_to_host(us));
        usb_stor_report_device_reset(us);
        scsi_unlock(us_to_host(us));
        us->transport_reset(us);
    }
    clear_bit(US_FLIDX_RESETTING, &us->dflags);
}

/*
 * ENE_stor_invoke_transport()
 */
void ENE_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
{
    int result = 0;

    /* pr_info("transport --- ENE_stor_invoke_transport\n"); */
    usb_stor_print_cmd(srb);
    /* send the command to the transport layer */
    scsi_set_resid(srb, 0);
    if (!(us->SM_Status.Ready))
        result = ENE_InitMedia(us);

    if (us->Power_IsResum == true) {
        result = ENE_InitMedia(us);
        us->Power_IsResum = false;
    }

    if (us->SM_Status.Ready)
        result = SM_SCSIIrp(us, srb);

    /* if the command gets aborted by the higher layers,
        we need to short-circuit all other processing */
    if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
        /* pr_info("-- command was aborted\n"); */
        srb->result = DID_ABORT << 16;
        goto Handle_Errors;
    }

    /* if there is a transport error, reset and don't auto-sense */
    if (result == USB_STOR_TRANSPORT_ERROR) {
        /* pr_info("-- transport indicates error, resetting\n"); */
        srb->result = DID_ERROR << 16;
        goto Handle_Errors;
    }

    /* if the transport provided its own sense data, don't auto-sense */
    if (result == USB_STOR_TRANSPORT_NO_SENSE) {
        srb->result = SAM_STAT_CHECK_CONDITION;
        return;
    }

    srb->result = SAM_STAT_GOOD;
    if (result == USB_STOR_TRANSPORT_FAILED) {
        /* pr_info("-- transport indicates command failure\n"); */
        /* need_auto_sense = 1; */
        BuildSenseBuffer(srb, us->SrbStatus);
        srb->result = SAM_STAT_CHECK_CONDITION;
    }

    /* Did we transfer less than the minimum amount required? */
    if (srb->result == SAM_STAT_GOOD && scsi_bufflen(srb) -
                    scsi_get_resid(srb) < srb->underflow)
        srb->result = (DID_ERROR << 16);
        /* v02 | (SUGGEST_RETRY << 24); */

    return;

Handle_Errors:
    scsi_lock(us_to_host(us));
    set_bit(US_FLIDX_RESETTING, &us->dflags);
    clear_bit(US_FLIDX_ABORTING, &us->dflags);
    scsi_unlock(us_to_host(us));

    mutex_unlock(&us->dev_mutex);
    result = usb_stor_port_reset(us);
    mutex_lock(&us->dev_mutex);

    if (result < 0) {
        scsi_lock(us_to_host(us));
        usb_stor_report_device_reset(us);
        scsi_unlock(us_to_host(us));
        us->transport_reset(us);
    }
    clear_bit(US_FLIDX_RESETTING, &us->dflags);
}

/*
 * BuildSenseBuffer()
 */
void BuildSenseBuffer(struct scsi_cmnd *srb, int SrbStatus)
{
    BYTE    *buf = srb->sense_buffer;
    BYTE    asc;

    pr_info("transport --- BuildSenseBuffer\n");
    switch (SrbStatus) {
    case SS_NOT_READY:
        asc = 0x3a;
        break;  /*  sense key = 0x02 */
    case SS_MEDIUM_ERR:
        asc = 0x0c;
        break;  /*  sense key = 0x03 */
    case SS_ILLEGAL_REQUEST:
        asc = 0x20;
        break;  /*  sense key = 0x05 */
    default:
        asc = 0x00;
        break;  /*  ?? */
    }

    memset(buf, 0, 18);
    buf[0x00] = 0xf0;
    buf[0x02] = SrbStatus;
    buf[0x07] = 0x0b;
    buf[0x0c] = asc;
}

/*
 * usb_stor_stop_transport()
 */
void usb_stor_stop_transport(struct us_data *us)
{
    /* pr_info("transport --- usb_stor_stop_transport\n"); */

    if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
        /* pr_info("-- cancelling URB\n"); */
        usb_unlink_urb(us->current_urb);
    }

    if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
        /* pr_info("-- cancelling sg request\n"); */
        usb_sg_cancel(&us->current_sg);
    }
}

/*
 * usb_stor_Bulk_max_lun()
 */
int usb_stor_Bulk_max_lun(struct us_data *us)
{
    int result;

    /* pr_info("transport --- usb_stor_Bulk_max_lun\n"); */
    /* issue the command */
    us->iobuf[0] = 0;
    result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
                 US_BULK_GET_MAX_LUN,
                 USB_DIR_IN | USB_TYPE_CLASS |
                 USB_RECIP_INTERFACE,
                 0, us->ifnum, us->iobuf, 1, HZ);

    /* pr_info("GetMaxLUN command result is %d, data is %d\n",
                        result, us->iobuf[0]); */

    /* if we have a successful request, return the result */
    if (result > 0)
        return us->iobuf[0];

    return 0;
}

/*
 * usb_stor_Bulk_transport()
 */
int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
{
    struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
    struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
    unsigned int transfer_length = scsi_bufflen(srb);
    unsigned int residue;
    int result;
    int fake_sense = 0;
    unsigned int cswlen;
    unsigned int cbwlen = US_BULK_CB_WRAP_LEN;

    /* pr_info("transport --- usb_stor_Bulk_transport\n"); */
    /* Take care of BULK32 devices; set extra byte to 0 */
    if (unlikely(us->fflags & US_FL_BULK32)) {
        cbwlen = 32;
        us->iobuf[31] = 0;
    }

    /* set up the command wrapper */
    bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
    bcb->DataTransferLength = cpu_to_le32(transfer_length);
    bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
    bcb->Tag = ++us->tag;
    bcb->Lun = srb->device->lun;
    if (us->fflags & US_FL_SCM_MULT_TARG)
        bcb->Lun |= srb->device->id << 4;
    bcb->Length = srb->cmd_len;

    /* copy the command payload */
    memset(bcb->CDB, 0, sizeof(bcb->CDB));
    memcpy(bcb->CDB, srb->cmnd, bcb->Length);

    /*  send command */
    /* send it to out endpoint */
    /* pr_info("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
            le32_to_cpu(bcb->Signature), bcb->Tag,
            le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
            (bcb->Lun >> 4), (bcb->Lun & 0x0F),
            bcb->Length); */
    result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
                        bcb, cbwlen, NULL);
    /* pr_info("Bulk command transfer result=%d\n", result); */
    if (result != USB_STOR_XFER_GOOD)
        return USB_STOR_TRANSPORT_ERROR;

    if (unlikely(us->fflags & US_FL_GO_SLOW))
        udelay(125);

    /*  R/W data */
    if (transfer_length) {
        unsigned int pipe;
        if (srb->sc_data_direction == DMA_FROM_DEVICE)
            pipe = us->recv_bulk_pipe;
        else
            pipe = us->send_bulk_pipe;

        result = usb_stor_bulk_srb(us, pipe, srb);
        /* pr_info("Bulk data transfer result 0x%x\n", result); */
        if (result == USB_STOR_XFER_ERROR)
            return USB_STOR_TRANSPORT_ERROR;

        if (result == USB_STOR_XFER_LONG)
            fake_sense = 1;
    }

    /* get CSW for device status */
    /* pr_info("Attempting to get CSW...\n"); */
    result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe, bcs,
                        US_BULK_CS_WRAP_LEN, &cswlen);

    if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
        /* pr_info("Received 0-length CSW; retrying...\n"); */
        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe, bcs,
                        US_BULK_CS_WRAP_LEN, &cswlen);
    }

    /* did the attempt to read the CSW fail? */
    if (result == USB_STOR_XFER_STALLED) {
        /* get the status again */
        /* pr_info("Attempting to get CSW (2nd try)...\n"); */
        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe, bcs,
                        US_BULK_CS_WRAP_LEN, NULL);
    }

    /* if we still have a failure at this point, we're in trouble */
    /* pr_info("Bulk status result = %d\n", result); */
    if (result != USB_STOR_XFER_GOOD)
        return USB_STOR_TRANSPORT_ERROR;

    /* check bulk status */
    residue = le32_to_cpu(bcs->Residue);
    /* pr_info("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
                le32_to_cpu(bcs->Signature),
                bcs->Tag, residue, bcs->Status); */
    if (!(bcs->Tag == us->tag ||
        (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
        bcs->Status > US_BULK_STAT_PHASE) {
        /* pr_info("Bulk logical error\n"); */
        return USB_STOR_TRANSPORT_ERROR;
    }

    if (!us->bcs_signature) {
        us->bcs_signature = bcs->Signature;
        /* if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN)) */
        /* pr_info("Learnt BCS signature 0x%08X\n",
                le32_to_cpu(us->bcs_signature)); */
    } else if (bcs->Signature != us->bcs_signature) {
        /* pr_info("Signature mismatch: got %08X, expecting %08X\n",
              le32_to_cpu(bcs->Signature),
              le32_to_cpu(us->bcs_signature)); */
        return USB_STOR_TRANSPORT_ERROR;
    }

    /* try to compute the actual residue, based on how much data
     * was really transferred and what the device tells us */
    if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {

        /* Heuristically detect devices that generate bogus residues
         * by seeing what happens with INQUIRY and READ CAPACITY
         * commands.
         */
        if (bcs->Status == US_BULK_STAT_OK &&
                scsi_get_resid(srb) == 0 &&
                    ((srb->cmnd[0] == INQUIRY &&
                        transfer_length == 36) ||
                    (srb->cmnd[0] == READ_CAPACITY &&
                        transfer_length == 8))) {
            us->fflags |= US_FL_IGNORE_RESIDUE;

        } else {
            residue = min(residue, transfer_length);
            scsi_set_resid(srb, max(scsi_get_resid(srb),
                            (int) residue));
        }
    }

    /* based on the status code, we report good or bad */
    switch (bcs->Status) {
    case US_BULK_STAT_OK:
        if (fake_sense) {
            memcpy(srb->sense_buffer, usb_stor_sense_invalidCDB,
                    sizeof(usb_stor_sense_invalidCDB));
            return USB_STOR_TRANSPORT_NO_SENSE;
        }
        return USB_STOR_TRANSPORT_GOOD;

    case US_BULK_STAT_FAIL:
        return USB_STOR_TRANSPORT_FAILED;

    case US_BULK_STAT_PHASE:
        return USB_STOR_TRANSPORT_ERROR;
    }
    return USB_STOR_TRANSPORT_ERROR;
}

/***********************************************************************
 * Reset routines
 ***********************************************************************/
/*
 * usb_stor_reset_common()
 */
static int usb_stor_reset_common(struct us_data *us,
        u8 request, u8 requesttype,
        u16 value, u16 index, void *data, u16 size)
{
    int result;
    int result2;

    /* pr_info("transport --- usb_stor_reset_common\n"); */
    if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
        /* pr_info("No reset during disconnect\n"); */
        return -EIO;
    }

    result = usb_stor_control_msg(us, us->send_ctrl_pipe,
            request, requesttype, value, index, data, size, 5*HZ);

    if (result < 0) {
        /* pr_info("Soft reset failed: %d\n", result); */
        return result;
    }

    wait_event_interruptible_timeout(us->delay_wait,
            test_bit(US_FLIDX_DISCONNECTING, &us->dflags),  HZ*6);

    if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
        /* pr_info("Reset interrupted by disconnect\n"); */
        return -EIO;
    }

    /* pr_info("Soft reset: clearing bulk-in endpoint halt\n"); */
    result = usb_stor_clear_halt(us, us->recv_bulk_pipe);

    /* pr_info("Soft reset: clearing bulk-out endpoint halt\n"); */
    result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);

    /* return a result code based on the result of the clear-halts */
    if (result >= 0)
        result = result2;
    /* if (result < 0) */
        /* pr_info("Soft reset failed\n"); */
    /* else */
        /* pr_info("Soft reset done\n"); */
    return result;
}

/*
 * usb_stor_Bulk_reset()
 */
int usb_stor_Bulk_reset(struct us_data *us)
{
    /* pr_info("transport --- usb_stor_Bulk_reset\n"); */
    return usb_stor_reset_common(us, US_BULK_RESET_REQUEST,
                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                 0, us->ifnum, NULL, 0);
}

/*
 * usb_stor_port_reset()
 */
int usb_stor_port_reset(struct us_data *us)
{
    int result;

    /* pr_info("transport --- usb_stor_port_reset\n"); */
    result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
    if (result < 0)
        pr_info("unable to lock device for reset: %d\n", result);
    else {
        /* Were we disconnected while waiting for the lock? */
        if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
            result = -EIO;
            /* pr_info("No reset during disconnect\n"); */
        } else {
            result = usb_reset_device(us->pusb_dev);
            /* pr_info("usb_reset_composite_device returns %d\n",
                                result); */
        }
        usb_unlock_device(us->pusb_dev);
    }
    return result;
}