[linux.git] / include / scsi / scsi_tcq.h

#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 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;
	struct scsi_device *sdev = cmd->device;

        if (blk_rq_tagged(req)) {
		if (sdev->ordered_tags && req->cmd_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;
}

/**
 * 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)
{
	shost->bqt = blk_init_tags(depth);
	return shost->bqt ? 0 : -ENOMEM;
}

/**
 * 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 */
Commit	Line	Data
1da177e4 LT	1	#ifndef _SCSI_SCSI_TCQ_H
	2	#define _SCSI_SCSI_TCQ_H
	3
	4	#include <linux/blkdev.h>
	5	#include <scsi/scsi_cmnd.h>
	6	#include <scsi/scsi_device.h>
86e33a29	7	#include <scsi/scsi_host.h>
1da177e4	8
1da177e4 LT	9	#define MSG_SIMPLE_TAG 0x20
	10	#define MSG_HEAD_TAG 0x21
	11	#define MSG_ORDERED_TAG 0x22
	12
	13	#define SCSI_NO_TAG (-1) /* identify no tag in use */
	14
	15
9361401e	16	#ifdef CONFIG_BLOCK
1da177e4 LT	17
	18	/**
	19	* scsi_get_tag_type - get the type of tag the device supports
	20	* @sdev: the scsi device
	21	*
	22	* Notes:
	23	* If the drive only supports simple tags, returns MSG_SIMPLE_TAG
	24	* if it supports all tag types, returns MSG_ORDERED_TAG.
	25	*/
	26	static inline int scsi_get_tag_type(struct scsi_device *sdev)
	27	{
	28	if (!sdev->tagged_supported)
	29	return 0;
	30	if (sdev->ordered_tags)
	31	return MSG_ORDERED_TAG;
	32	if (sdev->simple_tags)
	33	return MSG_SIMPLE_TAG;
	34	return 0;
	35	}
	36
	37	static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
	38	{
	39	switch (tag) {
	40	case MSG_ORDERED_TAG:
	41	sdev->ordered_tags = 1;
	42	/* fall through */
	43	case MSG_SIMPLE_TAG:
	44	sdev->simple_tags = 1;
	45	break;
	46	case 0:
	47	/* fall through */
	48	default:
	49	sdev->ordered_tags = 0;
	50	sdev->simple_tags = 0;
	51	break;
	52	}
	53	}
	54	/**
	55	* scsi_activate_tcq - turn on tag command queueing
	56	* @SDpnt: device to turn on TCQ for
	57	* @depth: queue depth
	58	*
	59	* Notes:
	60	* Eventually, I hope depth would be the maximum depth
	61	* the device could cope with and the real queue depth
	62	* would be adjustable from 0 to depth.
	63	**/
	64	static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
	65	{
	66	if (!sdev->tagged_supported)
	67	return;
	68
	69	if (!blk_queue_tagged(sdev->request_queue))
86e33a29 JB	70	blk_queue_init_tags(sdev->request_queue, depth,
86e33a29 JB	71	sdev->host->bqt);
1da177e4 LT	72
	73	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
	74	}
	75
	76	/**
	77	* scsi_deactivate_tcq - turn off tag command queueing
	78	* @SDpnt: device to turn off TCQ for
	79	**/
	80	static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
	81	{
	82	if (blk_queue_tagged(sdev->request_queue))
	83	blk_queue_free_tags(sdev->request_queue);
	84	scsi_adjust_queue_depth(sdev, 0, depth);
	85	}
	86
	87	/**
	88	* scsi_populate_tag_msg - place a tag message in a buffer
	89	* @SCpnt: pointer to the Scsi_Cmnd for the tag
	90	* @msg: pointer to the area to place the tag
	91	*
	92	* Notes:
	93	* designed to create the correct type of tag message for the
	94	* particular request. Returns the size of the tag message.
	95	* May return 0 if TCQ is disabled for this device.
	96	**/
	97	static inline int scsi_populate_tag_msg(struct scsi_cmnd cmd, char msg)
	98	{
	99	struct request *req = cmd->request;
	100	struct scsi_device *sdev = cmd->device;
	101
	102	if (blk_rq_tagged(req)) {
4aff5e23	103	if (sdev->ordered_tags && req->cmd_flags & REQ_HARDBARRIER)
1da177e4 LT	104	*msg++ = MSG_ORDERED_TAG;
	105	else
	106	*msg++ = MSG_SIMPLE_TAG;
	107	*msg++ = req->tag;
	108	return 2;
	109	}
	110
	111	return 0;
	112	}
	113
	114	/**
	115	* scsi_find_tag - find a tagged command by device
	116	* @SDpnt: pointer to the ScSI device
	117	* @tag: the tag number
	118	*
	119	* Notes:
	120	* Only works with tags allocated by the generic blk layer.
	121	**/
	122	static inline struct scsi_cmnd scsi_find_tag(struct scsi_device sdev, int tag)
	123	{
	124
	125	struct request *req;
	126
	127	if (tag != SCSI_NO_TAG) {
	128	req = blk_queue_find_tag(sdev->request_queue, tag);
	129	return req ? (struct scsi_cmnd *)req->special : NULL;
	130	}
	131
	132	/* single command, look in space */
	133	return sdev->current_cmnd;
	134	}
	135
86e33a29 JB	136	/**
	137	* scsi_init_shared_tag_map - create a shared tag map
	138	* @shost: the host to share the tag map among all devices
	139	* @depth: the total depth of the map
	140	*/
deb81d80	141	static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
86e33a29 JB	142	{
86e33a29 JB	143	shost->bqt = blk_init_tags(depth);
deb81d80	144	return shost->bqt ? 0 : -ENOMEM;
86e33a29 JB	145	}
86e33a29 JB	146
f583f492 DS	147	/**
	148	* scsi_host_find_tag - find the tagged command by host
	149	* @shost: pointer to scsi_host
	150	* @tag: tag of the scsi_cmnd
	151	*
	152	* Notes:
	153	* Only works with tags allocated by the generic blk layer.
	154	**/
	155	static inline struct scsi_cmnd scsi_host_find_tag(struct Scsi_Host shost,
	156	int tag)
	157	{
	158	struct request *req;
	159
	160	if (tag != SCSI_NO_TAG) {
	161	req = blk_map_queue_find_tag(shost->bqt, tag);
	162	return req ? (struct scsi_cmnd *)req->special : NULL;
	163	}
	164	return NULL;
	165	}
	166
9361401e	167	#endif /* CONFIG_BLOCK */
1da177e4	168	#endif /* _SCSI_SCSI_TCQ_H */