#ifndef _SCSI_SCSI_TCQ_H #define _SCSI_SCSI_TCQ_H #include <linux/blkdev.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_device.h> #define MSG_SIMPLE_TAG 0x20 #define MSG_HEAD_TAG 0x21 #define MSG_ORDERED_TAG 0x22 #define SCSI_NO_TAG (-1) /* identify no tag in use */ /** * 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, NULL); 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; struct scsi_device *sdev = cmd->device; if (blk_rq_tagged(req)) { if (sdev->ordered_tags && req->flags & REQ_HARDBARRIER) *msg++ = MSG_ORDERED_TAG; else *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; } #endif /* _SCSI_SCSI_TCQ_H */