scsi_tcq.h

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#ifndef _SCSI_SCSI_TCQ_H
#define _SCSI_SCSI_TCQ_H

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

#define MSG_SIMPLE_TAG  0x20
#define MSG_HEAD_TAG    0x21
#define MSG_ORDERED_TAG 0x22
#define MSG_ACA_TAG 0x24    /* unsupported */

#define SCSI_NO_TAG (-1)    /* identify no tag in use */


#ifdef CONFIG_BLOCK

static inline int scsi_get_tag_type(struct scsi_device *sdev)
{
    if (!sdev->tagged_supported)
        return 0;
    if (sdev->ordered_tags)
        return MSG_ORDERED_TAG;
    if (sdev->simple_tags)
        return MSG_SIMPLE_TAG;
    return 0;
}

static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
{
    switch (tag) {
    case MSG_ORDERED_TAG:
        sdev->ordered_tags = 1;
        /* fall through */
    case MSG_SIMPLE_TAG:
        sdev->simple_tags = 1;
        break;
    case 0:
        /* fall through */
    default:
        sdev->ordered_tags = 0;
        sdev->simple_tags = 0;
        break;
    }
}
static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
{
    if (!sdev->tagged_supported)
        return;

    if (!blk_queue_tagged(sdev->request_queue))
        blk_queue_init_tags(sdev->request_queue, depth,
                    sdev->host->bqt);

    scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
}

static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
{
    if (blk_queue_tagged(sdev->request_queue))
        blk_queue_free_tags(sdev->request_queue);
    scsi_adjust_queue_depth(sdev, 0, depth);
}

static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
{
        struct request *req = cmd->request;

        if (blk_rq_tagged(req)) {
        *msg++ = MSG_SIMPLE_TAG;
            *msg++ = req->tag;
            return 2;
    }

    return 0;
}

static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
{

        struct request *req;

        if (tag != SCSI_NO_TAG) {
            req = blk_queue_find_tag(sdev->request_queue, tag);
            return req ? (struct scsi_cmnd *)req->special : NULL;
    }

    /* single command, look in space */
    return sdev->current_cmnd;
}

static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
{
    /*
     * If the shared tag map isn't already initialized, do it now.
     * This saves callers from having to check ->bqt when setting up
     * devices on the shared host (for libata)
     */
    if (!shost->bqt) {
        shost->bqt = blk_init_tags(depth);
        if (!shost->bqt)
            return -ENOMEM;
    }

    return 0;
}

static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
                        int tag)
{
    struct request *req;

    if (tag != SCSI_NO_TAG) {
        req = blk_map_queue_find_tag(shost->bqt, tag);
        return req ? (struct scsi_cmnd *)req->special : NULL;
    }
    return NULL;
}

#endif /* CONFIG_BLOCK */
#endif /* _SCSI_SCSI_TCQ_H */