[net-next-2.6.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;

        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 */
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;
1da177e4 LT	100
1da177e4 LT	101	if (blk_rq_tagged(req)) {
9cbbdca4	102	*msg++ = MSG_SIMPLE_TAG;
1da177e4 LT	103	*msg++ = req->tag;
	104	return 2;
	105	}
	106
	107	return 0;
	108	}
	109
	110	/**
	111	* scsi_find_tag - find a tagged command by device
	112	* @SDpnt: pointer to the ScSI device
	113	* @tag: the tag number
	114	*
	115	* Notes:
	116	* Only works with tags allocated by the generic blk layer.
	117	**/
	118	static inline struct scsi_cmnd scsi_find_tag(struct scsi_device sdev, int tag)
	119	{
	120
	121	struct request *req;
	122
	123	if (tag != SCSI_NO_TAG) {
	124	req = blk_queue_find_tag(sdev->request_queue, tag);
	125	return req ? (struct scsi_cmnd *)req->special : NULL;
	126	}
	127
	128	/* single command, look in space */
	129	return sdev->current_cmnd;
	130	}
	131
86e33a29 JB	132	/**
	133	* scsi_init_shared_tag_map - create a shared tag map
	134	* @shost: the host to share the tag map among all devices
	135	* @depth: the total depth of the map
	136	*/
deb81d80	137	static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
86e33a29	138	{
3070f69b JA	139	/*
	140	* If the shared tag map isn't already initialized, do it now.
	141	* This saves callers from having to check ->bqt when setting up
	142	* devices on the shared host (for libata)
	143	*/
	144	if (!shost->bqt) {
	145	shost->bqt = blk_init_tags(depth);
	146	if (!shost->bqt)
	147	return -ENOMEM;
	148	}
	149
	150	return 0;
86e33a29 JB	151	}
86e33a29 JB	152
f583f492 DS	153	/**
	154	* scsi_host_find_tag - find the tagged command by host
	155	* @shost: pointer to scsi_host
	156	* @tag: tag of the scsi_cmnd
	157	*
	158	* Notes:
	159	* Only works with tags allocated by the generic blk layer.
	160	**/
	161	static inline struct scsi_cmnd scsi_host_find_tag(struct Scsi_Host shost,
	162	int tag)
	163	{
	164	struct request *req;
	165
	166	if (tag != SCSI_NO_TAG) {
	167	req = blk_map_queue_find_tag(shost->bqt, tag);
	168	return req ? (struct scsi_cmnd *)req->special : NULL;
	169	}
	170	return NULL;
	171	}
	172
9361401e	173	#endif /* CONFIG_BLOCK */
1da177e4	174	#endif /* _SCSI_SCSI_TCQ_H */