diff options
Diffstat (limited to 'include/scsi/scsi_tcq.h')
| -rw-r--r-- | include/scsi/scsi_tcq.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h new file mode 100644 index 00000000..81dd12ed --- /dev/null +++ b/include/scsi/scsi_tcq.h @@ -0,0 +1,175 @@ +#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 + +/** + * scsi_get_tag_type - get the type of tag the device supports + * @sdev: the scsi device + * + * Notes: + * If the drive only supports simple tags, returns MSG_SIMPLE_TAG + * if it supports all tag types, returns MSG_ORDERED_TAG. + */ +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; + } +} +/** + * scsi_activate_tcq - turn on tag command queueing + * @SDpnt: device to turn on TCQ for + * @depth: queue depth + * + * Notes: + * Eventually, I hope depth would be the maximum depth + * the device could cope with and the real queue depth + * would be adjustable from 0 to depth. + **/ +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); +} + +/** + * scsi_deactivate_tcq - turn off tag command queueing + * @SDpnt: device to turn off TCQ for + **/ +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); +} + +/** + * scsi_populate_tag_msg - place a tag message in a buffer + * @SCpnt: pointer to the Scsi_Cmnd for the tag + * @msg: pointer to the area to place the tag + * + * Notes: + * designed to create the correct type of tag message for the + * particular request. Returns the size of the tag message. + * May return 0 if TCQ is disabled for this device. + **/ +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; +} + +/** + * scsi_find_tag - find a tagged command by device + * @SDpnt: pointer to the ScSI device + * @tag: the tag number + * + * Notes: + * Only works with tags allocated by the generic blk layer. + **/ +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; +} + +/** + * scsi_init_shared_tag_map - create a shared tag map + * @shost: the host to share the tag map among all devices + * @depth: the total depth of the map + */ +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; +} + +/** + * scsi_host_find_tag - find the tagged command by host + * @shost: pointer to scsi_host + * @tag: tag of the scsi_cmnd + * + * Notes: + * Only works with tags allocated by the generic blk layer. + **/ +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 */ |