[linux-2.6-block.git] / drivers / scsi / arm / queue.c

/*
 *  linux/drivers/acorn/scsi/queue.c: queue handling primitives
 *
 *  Copyright (C) 1997-2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Changelog:
 *   15-Sep-1997 RMK	Created.
 *   11-Oct-1997 RMK	Corrected problem with queue_remove_exclude
 *			not updating internal linked list properly
 *			(was causing commands to go missing).
 *   30-Aug-2000 RMK	Use Linux list handling and spinlocks
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/init.h>

#include "../scsi.h"

#define DEBUG

typedef struct queue_entry {
	struct list_head   list;
	struct scsi_cmnd   *SCpnt;
#ifdef DEBUG
	unsigned long	   magic;
#endif
} QE_t;

#ifdef DEBUG
#define QUEUE_MAGIC_FREE	0xf7e1c9a3
#define QUEUE_MAGIC_USED	0xf7e1cc33

#define SET_MAGIC(q,m)	((q)->magic = (m))
#define BAD_MAGIC(q,m)	((q)->magic != (m))
#else
#define SET_MAGIC(q,m)	do { } while (0)
#define BAD_MAGIC(q,m)	(0)
#endif

#include "queue.h"

#define NR_QE	32

/*
 * Function: void queue_initialise (Queue_t *queue)
 * Purpose : initialise a queue
 * Params  : queue - queue to initialise
 */
int queue_initialise (Queue_t *queue)
{
	unsigned int nqueues = NR_QE;
	QE_t *q;

	spin_lock_init(&queue->queue_lock);
	INIT_LIST_HEAD(&queue->head);
	INIT_LIST_HEAD(&queue->free);

	/*
	 * If life was easier, then SCpnt would have a
	 * host-available list head, and we wouldn't
	 * need to keep free lists or allocate this
	 * memory.
	 */
	queue->alloc = q = kmalloc(sizeof(QE_t) * nqueues, GFP_KERNEL);
	if (q) {
		for (; nqueues; q++, nqueues--) {
			SET_MAGIC(q, QUEUE_MAGIC_FREE);
			q->SCpnt = NULL;
			list_add(&q->list, &queue->free);
		}
	}

	return queue->alloc != NULL;
}

/*
 * Function: void queue_free (Queue_t *queue)
 * Purpose : free a queue
 * Params  : queue - queue to free
 */
void queue_free (Queue_t *queue)
{
	if (!list_empty(&queue->head))
		printk(KERN_WARNING "freeing non-empty queue %p\n", queue);
	kfree(queue->alloc);
}
     

/*
 * Function: int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head)
 * Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
 * Params  : queue - destination queue
 *	     SCpnt - command to add
 *	     head  - add command to head of queue
 * Returns : 0 on error, !0 on success
 */
int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head)
{
	unsigned long flags;
	struct list_head *l;
	QE_t *q;
	int ret = 0;

	spin_lock_irqsave(&queue->queue_lock, flags);
	if (list_empty(&queue->free))
		goto empty;

	l = queue->free.next;
	list_del(l);

	q = list_entry(l, QE_t, list);
	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_FREE));

	SET_MAGIC(q, QUEUE_MAGIC_USED);
	q->SCpnt = SCpnt;

	if (head)
		list_add(l, &queue->head);
	else
		list_add_tail(l, &queue->head);

	ret = 1;
empty:
	spin_unlock_irqrestore(&queue->queue_lock, flags);
	return ret;
}

static struct scsi_cmnd *__queue_remove(Queue_t *queue, struct list_head *ent)
{
	QE_t *q;

	/*
	 * Move the entry from the "used" list onto the "free" list
	 */
	list_del(ent);
	q = list_entry(ent, QE_t, list);
	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_USED));

	SET_MAGIC(q, QUEUE_MAGIC_FREE);
	list_add(ent, &queue->free);

	return q->SCpnt;
}

/*
 * Function: struct scsi_cmnd *queue_remove_exclude (queue, exclude)
 * Purpose : remove a SCSI command from a queue
 * Params  : queue   - queue to remove command from
 *	     exclude - bit array of target&lun which is busy
 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
 */
struct scsi_cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude)
{
	unsigned long flags;
	struct list_head *l;
	struct scsi_cmnd *SCpnt = NULL;

	spin_lock_irqsave(&queue->queue_lock, flags);
	list_for_each(l, &queue->head) {
		QE_t *q = list_entry(l, QE_t, list);
		if (!test_bit(q->SCpnt->device->id * 8 + q->SCpnt->device->lun, exclude)) {
			SCpnt = __queue_remove(queue, l);
			break;
		}
	}
	spin_unlock_irqrestore(&queue->queue_lock, flags);

	return SCpnt;
}

/*
 * Function: struct scsi_cmnd *queue_remove (queue)
 * Purpose : removes first SCSI command from a queue
 * Params  : queue   - queue to remove command from
 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
 */
struct scsi_cmnd *queue_remove(Queue_t *queue)
{
	unsigned long flags;
	struct scsi_cmnd *SCpnt = NULL;

	spin_lock_irqsave(&queue->queue_lock, flags);
	if (!list_empty(&queue->head))
		SCpnt = __queue_remove(queue, queue->head.next);
	spin_unlock_irqrestore(&queue->queue_lock, flags);

	return SCpnt;
}

/*
 * Function: struct scsi_cmnd *queue_remove_tgtluntag (queue, target, lun, tag)
 * Purpose : remove a SCSI command from the queue for a specified target/lun/tag
 * Params  : queue  - queue to remove command from
 *	     target - target that we want
 *	     lun    - lun on device
 *	     tag    - tag on device
 * Returns : struct scsi_cmnd if successful, or NULL if no command satisfies requirements
 */
struct scsi_cmnd *queue_remove_tgtluntag(Queue_t *queue, int target, int lun,
					 int tag)
{
	unsigned long flags;
	struct list_head *l;
	struct scsi_cmnd *SCpnt = NULL;

	spin_lock_irqsave(&queue->queue_lock, flags);
	list_for_each(l, &queue->head) {
		QE_t *q = list_entry(l, QE_t, list);
		if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun &&
		    q->SCpnt->tag == tag) {
			SCpnt = __queue_remove(queue, l);
			break;
		}
	}
	spin_unlock_irqrestore(&queue->queue_lock, flags);

	return SCpnt;
}

/*
 * Function: queue_remove_all_target(queue, target)
 * Purpose : remove all SCSI commands from the queue for a specified target
 * Params  : queue  - queue to remove command from
 *           target - target device id
 * Returns : nothing
 */
void queue_remove_all_target(Queue_t *queue, int target)
{
	unsigned long flags;
	struct list_head *l;

	spin_lock_irqsave(&queue->queue_lock, flags);
	list_for_each(l, &queue->head) {
		QE_t *q = list_entry(l, QE_t, list);
		if (q->SCpnt->device->id == target)
			__queue_remove(queue, l);
	}
	spin_unlock_irqrestore(&queue->queue_lock, flags);
}

/*
 * Function: int queue_probetgtlun (queue, target, lun)
 * Purpose : check to see if we have a command in the queue for the specified
 *	     target/lun.
 * Params  : queue  - queue to look in
 *	     target - target we want to probe
 *	     lun    - lun on target
 * Returns : 0 if not found, != 0 if found
 */
int queue_probetgtlun (Queue_t *queue, int target, int lun)
{
	unsigned long flags;
	struct list_head *l;
	int found = 0;

	spin_lock_irqsave(&queue->queue_lock, flags);
	list_for_each(l, &queue->head) {
		QE_t *q = list_entry(l, QE_t, list);
		if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun) {
			found = 1;
			break;
		}
	}
	spin_unlock_irqrestore(&queue->queue_lock, flags);

	return found;
}

/*
 * Function: int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
 * Purpose : remove a specific command from the queues
 * Params  : queue - queue to look in
 *	     SCpnt - command to find
 * Returns : 0 if not found
 */
int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
{
	unsigned long flags;
	struct list_head *l;
	int found = 0;

	spin_lock_irqsave(&queue->queue_lock, flags);
	list_for_each(l, &queue->head) {
		QE_t *q = list_entry(l, QE_t, list);
		if (q->SCpnt == SCpnt) {
			__queue_remove(queue, l);
			found = 1;
			break;
		}
	}
	spin_unlock_irqrestore(&queue->queue_lock, flags);

	return found;
}

EXPORT_SYMBOL(queue_initialise);
EXPORT_SYMBOL(queue_free);
EXPORT_SYMBOL(__queue_add);
EXPORT_SYMBOL(queue_remove);
EXPORT_SYMBOL(queue_remove_exclude);
EXPORT_SYMBOL(queue_remove_tgtluntag);
EXPORT_SYMBOL(queue_remove_cmd);
EXPORT_SYMBOL(queue_remove_all_target);
EXPORT_SYMBOL(queue_probetgtlun);

MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("SCSI command queueing");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/acorn/scsi/queue.c: queue handling primitives
	3	*
	4	* Copyright (C) 1997-2000 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* Changelog:
	11	* 15-Sep-1997 RMK Created.
	12	* 11-Oct-1997 RMK Corrected problem with queue_remove_exclude
	13	* not updating internal linked list properly
	14	* (was causing commands to go missing).
	15	* 30-Aug-2000 RMK Use Linux list handling and spinlocks
	16	*/
	17	#include <linux/module.h>
	18	#include <linux/blkdev.h>
	19	#include <linux/kernel.h>
	20	#include <linux/string.h>
	21	#include <linux/slab.h>
	22	#include <linux/spinlock.h>
	23	#include <linux/list.h>
	24	#include <linux/init.h>
	25
	26	#include "../scsi.h"
	27
	28	#define DEBUG
	29
	30	typedef struct queue_entry {
	31	struct list_head list;
ee0ca6ba	32	struct scsi_cmnd *SCpnt;
1da177e4 LT	33	#ifdef DEBUG
	34	unsigned long magic;
	35	#endif
	36	} QE_t;
	37
	38	#ifdef DEBUG
	39	#define QUEUE_MAGIC_FREE 0xf7e1c9a3
	40	#define QUEUE_MAGIC_USED 0xf7e1cc33
	41
	42	#define SET_MAGIC(q,m) ((q)->magic = (m))
	43	#define BAD_MAGIC(q,m) ((q)->magic != (m))
	44	#else
	45	#define SET_MAGIC(q,m) do { } while (0)
	46	#define BAD_MAGIC(q,m) (0)
	47	#endif
	48
	49	#include "queue.h"
	50
	51	#define NR_QE 32
	52
	53	/*
	54	* Function: void queue_initialise (Queue_t *queue)
	55	* Purpose : initialise a queue
	56	* Params : queue - queue to initialise
	57	*/
	58	int queue_initialise (Queue_t *queue)
	59	{
	60	unsigned int nqueues = NR_QE;
	61	QE_t *q;
	62
	63	spin_lock_init(&queue->queue_lock);
	64	INIT_LIST_HEAD(&queue->head);
	65	INIT_LIST_HEAD(&queue->free);
	66
	67	/*
	68	* If life was easier, then SCpnt would have a
	69	* host-available list head, and we wouldn't
	70	* need to keep free lists or allocate this
	71	* memory.
	72	*/
	73	queue->alloc = q = kmalloc(sizeof(QE_t) * nqueues, GFP_KERNEL);
	74	if (q) {
	75	for (; nqueues; q++, nqueues--) {
	76	SET_MAGIC(q, QUEUE_MAGIC_FREE);
	77	q->SCpnt = NULL;
	78	list_add(&q->list, &queue->free);
	79	}
	80	}
	81
	82	return queue->alloc != NULL;
	83	}
	84
	85	/*
	86	* Function: void queue_free (Queue_t *queue)
	87	* Purpose : free a queue
	88	* Params : queue - queue to free
	89	*/
	90	void queue_free (Queue_t *queue)
	91	{
	92	if (!list_empty(&queue->head))
	93	printk(KERN_WARNING "freeing non-empty queue %p\n", queue);
c9475cb0	94	kfree(queue->alloc);
1da177e4 LT	95	}
	96
	97
	98	/*
ee0ca6ba	99	* Function: int __queue_add(Queue_t queue, struct scsi_cmnd SCpnt, int head)
1da177e4 LT	100	* Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
	101	* Params : queue - destination queue
	102	* SCpnt - command to add
	103	* head - add command to head of queue
	104	* Returns : 0 on error, !0 on success
	105	*/
ee0ca6ba	106	int __queue_add(Queue_t queue, struct scsi_cmnd SCpnt, int head)
1da177e4 LT	107	{
	108	unsigned long flags;
	109	struct list_head *l;
	110	QE_t *q;
	111	int ret = 0;
	112
	113	spin_lock_irqsave(&queue->queue_lock, flags);
	114	if (list_empty(&queue->free))
	115	goto empty;
	116
	117	l = queue->free.next;
	118	list_del(l);
	119
	120	q = list_entry(l, QE_t, list);
125e1874	121	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_FREE));
1da177e4 LT	122
	123	SET_MAGIC(q, QUEUE_MAGIC_USED);
	124	q->SCpnt = SCpnt;
	125
	126	if (head)
	127	list_add(l, &queue->head);
	128	else
	129	list_add_tail(l, &queue->head);
	130
	131	ret = 1;
	132	empty:
	133	spin_unlock_irqrestore(&queue->queue_lock, flags);
	134	return ret;
	135	}
	136
ee0ca6ba	137	static struct scsi_cmnd __queue_remove(Queue_t queue, struct list_head *ent)
1da177e4 LT	138	{
	139	QE_t *q;
	140
	141	/*
	142	* Move the entry from the "used" list onto the "free" list
	143	*/
	144	list_del(ent);
	145	q = list_entry(ent, QE_t, list);
125e1874	146	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_USED));
1da177e4 LT	147
	148	SET_MAGIC(q, QUEUE_MAGIC_FREE);
	149	list_add(ent, &queue->free);
	150
	151	return q->SCpnt;
	152	}
	153
	154	/*
ee0ca6ba	155	* Function: struct scsi_cmnd *queue_remove_exclude (queue, exclude)
1da177e4 LT	156	* Purpose : remove a SCSI command from a queue
	157	* Params : queue - queue to remove command from
	158	* exclude - bit array of target&lun which is busy
ee0ca6ba	159	* Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
1da177e4	160	*/
ee0ca6ba	161	struct scsi_cmnd queue_remove_exclude(Queue_t queue, unsigned long *exclude)
1da177e4 LT	162	{
	163	unsigned long flags;
	164	struct list_head *l;
ee0ca6ba	165	struct scsi_cmnd *SCpnt = NULL;
1da177e4 LT	166
	167	spin_lock_irqsave(&queue->queue_lock, flags);
	168	list_for_each(l, &queue->head) {
	169	QE_t *q = list_entry(l, QE_t, list);
	170	if (!test_bit(q->SCpnt->device->id * 8 + q->SCpnt->device->lun, exclude)) {
	171	SCpnt = __queue_remove(queue, l);
	172	break;
	173	}
	174	}
	175	spin_unlock_irqrestore(&queue->queue_lock, flags);
	176
	177	return SCpnt;
	178	}
	179
	180	/*
ee0ca6ba	181	* Function: struct scsi_cmnd *queue_remove (queue)
1da177e4 LT	182	* Purpose : removes first SCSI command from a queue
1da177e4 LT	183	* Params : queue - queue to remove command from
ee0ca6ba	184	* Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
1da177e4	185	*/
ee0ca6ba	186	struct scsi_cmnd queue_remove(Queue_t queue)
1da177e4 LT	187	{
1da177e4 LT	188	unsigned long flags;
ee0ca6ba	189	struct scsi_cmnd *SCpnt = NULL;
1da177e4 LT	190
	191	spin_lock_irqsave(&queue->queue_lock, flags);
	192	if (!list_empty(&queue->head))
	193	SCpnt = __queue_remove(queue, queue->head.next);
	194	spin_unlock_irqrestore(&queue->queue_lock, flags);
	195
	196	return SCpnt;
	197	}
	198
	199	/*
ee0ca6ba	200	* Function: struct scsi_cmnd *queue_remove_tgtluntag (queue, target, lun, tag)
1da177e4 LT	201	* Purpose : remove a SCSI command from the queue for a specified target/lun/tag
	202	* Params : queue - queue to remove command from
	203	* target - target that we want
	204	* lun - lun on device
	205	* tag - tag on device
ee0ca6ba	206	* Returns : struct scsi_cmnd if successful, or NULL if no command satisfies requirements
1da177e4	207	*/
ee0ca6ba H	208	struct scsi_cmnd queue_remove_tgtluntag(Queue_t queue, int target, int lun,
ee0ca6ba H	209	int tag)
1da177e4 LT	210	{
	211	unsigned long flags;
	212	struct list_head *l;
ee0ca6ba	213	struct scsi_cmnd *SCpnt = NULL;
1da177e4 LT	214
	215	spin_lock_irqsave(&queue->queue_lock, flags);
	216	list_for_each(l, &queue->head) {
	217	QE_t *q = list_entry(l, QE_t, list);
	218	if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun &&
	219	q->SCpnt->tag == tag) {
	220	SCpnt = __queue_remove(queue, l);
	221	break;
	222	}
	223	}
	224	spin_unlock_irqrestore(&queue->queue_lock, flags);
	225
	226	return SCpnt;
	227	}
	228
	229	/*
	230	* Function: queue_remove_all_target(queue, target)
	231	* Purpose : remove all SCSI commands from the queue for a specified target
	232	* Params : queue - queue to remove command from
	233	* target - target device id
	234	* Returns : nothing
	235	*/
	236	void queue_remove_all_target(Queue_t *queue, int target)
	237	{
	238	unsigned long flags;
	239	struct list_head *l;
	240
	241	spin_lock_irqsave(&queue->queue_lock, flags);
	242	list_for_each(l, &queue->head) {
	243	QE_t *q = list_entry(l, QE_t, list);
	244	if (q->SCpnt->device->id == target)
	245	__queue_remove(queue, l);
	246	}
	247	spin_unlock_irqrestore(&queue->queue_lock, flags);
	248	}
	249
	250	/*
	251	* Function: int queue_probetgtlun (queue, target, lun)
	252	* Purpose : check to see if we have a command in the queue for the specified
	253	* target/lun.
	254	* Params : queue - queue to look in
	255	* target - target we want to probe
	256	* lun - lun on target
	257	* Returns : 0 if not found, != 0 if found
	258	*/
	259	int queue_probetgtlun (Queue_t *queue, int target, int lun)
	260	{
	261	unsigned long flags;
	262	struct list_head *l;
	263	int found = 0;
	264
	265	spin_lock_irqsave(&queue->queue_lock, flags);
	266	list_for_each(l, &queue->head) {
	267	QE_t *q = list_entry(l, QE_t, list);
	268	if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun) {
	269	found = 1;
	270	break;
	271	}
	272	}
	273	spin_unlock_irqrestore(&queue->queue_lock, flags);
	274
	275	return found;
	276	}
	277
278	/*
ee0ca6ba	279	* Function: int queue_remove_cmd(Queue_t queue, struct scsi_cmnd SCpnt)
1da177e4 LT	280	* Purpose : remove a specific command from the queues
	281	* Params : queue - queue to look in
	282	* SCpnt - command to find
	283	* Returns : 0 if not found
	284	*/
ee0ca6ba	285	int queue_remove_cmd(Queue_t queue, struct scsi_cmnd SCpnt)
1da177e4 LT	286	{
	287	unsigned long flags;
	288	struct list_head *l;
	289	int found = 0;
	290
	291	spin_lock_irqsave(&queue->queue_lock, flags);
	292	list_for_each(l, &queue->head) {
	293	QE_t *q = list_entry(l, QE_t, list);
	294	if (q->SCpnt == SCpnt) {
	295	__queue_remove(queue, l);
	296	found = 1;
	297	break;
	298	}
	299	}
	300	spin_unlock_irqrestore(&queue->queue_lock, flags);
	301
	302	return found;
	303	}
	304
	305	EXPORT_SYMBOL(queue_initialise);
	306	EXPORT_SYMBOL(queue_free);
	307	EXPORT_SYMBOL(__queue_add);
	308	EXPORT_SYMBOL(queue_remove);
	309	EXPORT_SYMBOL(queue_remove_exclude);
	310	EXPORT_SYMBOL(queue_remove_tgtluntag);
	311	EXPORT_SYMBOL(queue_remove_cmd);
	312	EXPORT_SYMBOL(queue_remove_all_target);
	313	EXPORT_SYMBOL(queue_probetgtlun);
	314
	315	MODULE_AUTHOR("Russell King");
	316	MODULE_DESCRIPTION("SCSI command queueing");
	317	MODULE_LICENSE("GPL");