scsi.h

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/*
 *  linux/drivers/acorn/scsi/scsi.h
 *
 *  Copyright (C) 2002 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Commonly used scsi driver functions.
 */

#include <linux/scatterlist.h>

#define BELT_AND_BRACES

/*
 * The scatter-gather list handling.  This contains all
 * the yucky stuff that needs to be fixed properly.
 */

/*
 * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
 * entries of uninitialized memory. SCp is from scsi-ml and has a valid
 * (possibly chained) sg-list
 */
static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
{
    int bufs = SCp->buffers_residual;

    /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
     * and to remove this BUG_ON. Use min() in-its-place
     */
    BUG_ON(bufs + 1 > max);

    sg_set_buf(sg, SCp->ptr, SCp->this_residual);

    if (bufs) {
        struct scatterlist *src_sg;
        unsigned i;

        for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
            *(++sg) = *src_sg;
        sg_mark_end(sg);
    }

    return bufs + 1;
}

static inline int next_SCp(struct scsi_pointer *SCp)
{
    int ret = SCp->buffers_residual;
    if (ret) {
        SCp->buffer = sg_next(SCp->buffer);
        SCp->buffers_residual--;
        SCp->ptr = sg_virt(SCp->buffer);
        SCp->this_residual = SCp->buffer->length;
    } else {
        SCp->ptr = NULL;
        SCp->this_residual = 0;
    }
    return ret;
}

static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
{
    char c = *SCp->ptr;

    SCp->ptr += 1;
    SCp->this_residual -= 1;

    return c;
}

static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
{
    *SCp->ptr = c;
    SCp->ptr += 1;
    SCp->this_residual -= 1;
}

static inline void init_SCp(struct scsi_cmnd *SCpnt)
{
    memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));

    if (scsi_bufflen(SCpnt)) {
        unsigned long len = 0;

        SCpnt->SCp.buffer = scsi_sglist(SCpnt);
        SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
        SCpnt->SCp.ptr = sg_virt(SCpnt->SCp.buffer);
        SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
        SCpnt->SCp.phase = scsi_bufflen(SCpnt);

#ifdef BELT_AND_BRACES
        {   /*
             * Calculate correct buffer length.  Some commands
             * come in with the wrong scsi_bufflen.
             */
            struct scatterlist *sg;
            unsigned i, sg_count = scsi_sg_count(SCpnt);

            scsi_for_each_sg(SCpnt, sg, sg_count, i)
                len += sg->length;

            if (scsi_bufflen(SCpnt) != len) {
                printk(KERN_WARNING
                       "scsi%d.%c: bad request buffer "
                       "length %d, should be %ld\n",
                    SCpnt->device->host->host_no,
                    '0' + SCpnt->device->id,
                    scsi_bufflen(SCpnt), len);
                /*
                 * FIXME: Totaly naive fixup. We should abort
                 * with error
                 */
                SCpnt->SCp.phase =
                    min_t(unsigned long, len,
                          scsi_bufflen(SCpnt));
            }
        }
#endif
    } else {
        SCpnt->SCp.ptr = NULL;
        SCpnt->SCp.this_residual = 0;
        SCpnt->SCp.phase = 0;
    }
}