[linux-2.6-block.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>


#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 */
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>
	7
	8
	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
	16
	17	/**
	18	* scsi_get_tag_type - get the type of tag the device supports
	19	* @sdev: the scsi device
	20	*
	21	* Notes:
	22	* If the drive only supports simple tags, returns MSG_SIMPLE_TAG
	23	* if it supports all tag types, returns MSG_ORDERED_TAG.
	24	*/
	25	static inline int scsi_get_tag_type(struct scsi_device *sdev)
	26	{
	27	if (!sdev->tagged_supported)
	28	return 0;
	29	if (sdev->ordered_tags)
	30	return MSG_ORDERED_TAG;
	31	if (sdev->simple_tags)
	32	return MSG_SIMPLE_TAG;
	33	return 0;
	34	}
	35
	36	static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
	37	{
	38	switch (tag) {
	39	case MSG_ORDERED_TAG:
	40	sdev->ordered_tags = 1;
	41	/* fall through */
	42	case MSG_SIMPLE_TAG:
	43	sdev->simple_tags = 1;
	44	break;
	45	case 0:
	46	/* fall through */
	47	default:
	48	sdev->ordered_tags = 0;
	49	sdev->simple_tags = 0;
	50	break;
	51	}
	52	}
	53	/**
	54	* scsi_activate_tcq - turn on tag command queueing
	55	* @SDpnt: device to turn on TCQ for
	56	* @depth: queue depth
	57	*
	58	* Notes:
	59	* Eventually, I hope depth would be the maximum depth
	60	* the device could cope with and the real queue depth
	61	* would be adjustable from 0 to depth.
	62	**/
	63	static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
	64	{
65	if (!sdev->tagged_supported)
66	return;
67
68	if (!blk_queue_tagged(sdev->request_queue))
69	blk_queue_init_tags(sdev->request_queue, depth, NULL);
70
71	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
72	}
73
74	/**
75	* scsi_deactivate_tcq - turn off tag command queueing
76	* @SDpnt: device to turn off TCQ for
77	**/
78	static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
79	{
80	if (blk_queue_tagged(sdev->request_queue))
81	blk_queue_free_tags(sdev->request_queue);
82	scsi_adjust_queue_depth(sdev, 0, depth);
83	}
84
85	/**
86	* scsi_populate_tag_msg - place a tag message in a buffer
87	* @SCpnt: pointer to the Scsi_Cmnd for the tag
88	* @msg: pointer to the area to place the tag
89	*
90	* Notes:
91	* designed to create the correct type of tag message for the
92	* particular request. Returns the size of the tag message.
93	* May return 0 if TCQ is disabled for this device.
94	**/
95	static inline int scsi_populate_tag_msg(struct scsi_cmnd cmd, char msg)
96	{
97	struct request *req = cmd->request;
98	struct scsi_device *sdev = cmd->device;
99
100	if (blk_rq_tagged(req)) {
101	if (sdev->ordered_tags && req->flags & REQ_HARDBARRIER)
102	*msg++ = MSG_ORDERED_TAG;
103	else
104	*msg++ = MSG_SIMPLE_TAG;
105	*msg++ = req->tag;
106	return 2;
107	}
108
109	return 0;
110	}
111
112	/**
113	* scsi_find_tag - find a tagged command by device
114	* @SDpnt: pointer to the ScSI device
115	* @tag: the tag number
116	*
117	* Notes:
118	* Only works with tags allocated by the generic blk layer.
119	**/
120	static inline struct scsi_cmnd scsi_find_tag(struct scsi_device sdev, int tag)
121	{
122
123	struct request *req;
124
125	if (tag != SCSI_NO_TAG) {
126	req = blk_queue_find_tag(sdev->request_queue, tag);
127	return req ? (struct scsi_cmnd *)req->special : NULL;
128	}
129
130	/* single command, look in space */
131	return sdev->current_cmnd;
132	}
133
134	#endif /* _SCSI_SCSI_TCQ_H */