[linux-2.6] / 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;
	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_cmd(Queue_t *queue, 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, 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);
	if (BAD_MAGIC(q, QUEUE_MAGIC_FREE))
		BUG();

	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 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);
	if (BAD_MAGIC(q, QUEUE_MAGIC_USED))
		BUG();

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

	return q->SCpnt;
}

/*
 * Function: 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 : Scsi_Cmnd if successful (and a reference), or NULL if no command available
 */
Scsi_Cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude)
{
	unsigned long flags;
	struct list_head *l;
	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: Scsi_Cmnd *queue_remove (queue)
 * Purpose : removes first SCSI command from a queue
 * Params  : queue   - queue to remove command from
 * Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available
 */
Scsi_Cmnd *queue_remove(Queue_t *queue)
{
	unsigned long flags;
	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: 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 : Scsi_Cmnd if successful, or NULL if no command satisfies requirements
 */
Scsi_Cmnd *queue_remove_tgtluntag (Queue_t *queue, int target, int lun, int tag)
{
	unsigned long flags;
	struct list_head *l;
	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, 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, 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;
	32	Scsi_Cmnd *SCpnt;
	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	/*
	99	* Function: int queue_add_cmd(Queue_t queue, Scsi_Cmnd SCpnt, int head)
	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	*/
	106	int __queue_add(Queue_t queue, Scsi_Cmnd SCpnt, int head)
	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);
	121	if (BAD_MAGIC(q, QUEUE_MAGIC_FREE))
	122	BUG();
	123
	124	SET_MAGIC(q, QUEUE_MAGIC_USED);
	125	q->SCpnt = SCpnt;
	126
	127	if (head)
	128	list_add(l, &queue->head);
	129	else
	130	list_add_tail(l, &queue->head);
	131
	132	ret = 1;
	133	empty:
	134	spin_unlock_irqrestore(&queue->queue_lock, flags);
	135	return ret;
	136	}
	137
	138	static Scsi_Cmnd __queue_remove(Queue_t queue, struct list_head *ent)
	139	{
	140	QE_t *q;
	141
	142	/*
	143	* Move the entry from the "used" list onto the "free" list
	144	*/
	145	list_del(ent);
	146	q = list_entry(ent, QE_t, list);
	147	if (BAD_MAGIC(q, QUEUE_MAGIC_USED))
	148	BUG();
	149
	150	SET_MAGIC(q, QUEUE_MAGIC_FREE);
	151	list_add(ent, &queue->free);
	152
	153	return q->SCpnt;
	154	}
	155
	156	/*
	157	* Function: Scsi_Cmnd *queue_remove_exclude (queue, exclude)
	158	* Purpose : remove a SCSI command from a queue
159	* Params : queue - queue to remove command from
160	* exclude - bit array of target&lun which is busy
161	* Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available
162	*/
163	Scsi_Cmnd queue_remove_exclude(Queue_t queue, unsigned long *exclude)
164	{
165	unsigned long flags;
166	struct list_head *l;
167	Scsi_Cmnd *SCpnt = NULL;
168
169	spin_lock_irqsave(&queue->queue_lock, flags);
170	list_for_each(l, &queue->head) {
171	QE_t *q = list_entry(l, QE_t, list);
172	if (!test_bit(q->SCpnt->device->id * 8 + q->SCpnt->device->lun, exclude)) {
173	SCpnt = __queue_remove(queue, l);
174	break;
175	}
176	}
177	spin_unlock_irqrestore(&queue->queue_lock, flags);
178
179	return SCpnt;
180	}
181
182	/*
183	* Function: Scsi_Cmnd *queue_remove (queue)
184	* Purpose : removes first SCSI command from a queue
185	* Params : queue - queue to remove command from
186	* Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available
187	*/
188	Scsi_Cmnd queue_remove(Queue_t queue)
189	{
190	unsigned long flags;
191	Scsi_Cmnd *SCpnt = NULL;
192
193	spin_lock_irqsave(&queue->queue_lock, flags);
194	if (!list_empty(&queue->head))
195	SCpnt = __queue_remove(queue, queue->head.next);
196	spin_unlock_irqrestore(&queue->queue_lock, flags);
197
198	return SCpnt;
199	}
200
201	/*
202	* Function: Scsi_Cmnd *queue_remove_tgtluntag (queue, target, lun, tag)
203	* Purpose : remove a SCSI command from the queue for a specified target/lun/tag
204	* Params : queue - queue to remove command from
205	* target - target that we want
206	* lun - lun on device
207	* tag - tag on device
208	* Returns : Scsi_Cmnd if successful, or NULL if no command satisfies requirements
209	*/
210	Scsi_Cmnd queue_remove_tgtluntag (Queue_t queue, int target, int lun, int tag)
211	{
212	unsigned long flags;
213	struct list_head *l;
214	Scsi_Cmnd *SCpnt = NULL;
215
216	spin_lock_irqsave(&queue->queue_lock, flags);
217	list_for_each(l, &queue->head) {
218	QE_t *q = list_entry(l, QE_t, list);
219	if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun &&
220	q->SCpnt->tag == tag) {
221	SCpnt = __queue_remove(queue, l);
222	break;
223	}
224	}
225	spin_unlock_irqrestore(&queue->queue_lock, flags);
226
227	return SCpnt;
228	}
229
230	/*
231	* Function: queue_remove_all_target(queue, target)
232	* Purpose : remove all SCSI commands from the queue for a specified target
233	* Params : queue - queue to remove command from
234	* target - target device id
235	* Returns : nothing
236	*/
237	void queue_remove_all_target(Queue_t *queue, int target)
238	{
239	unsigned long flags;
240	struct list_head *l;
241
242	spin_lock_irqsave(&queue->queue_lock, flags);
243	list_for_each(l, &queue->head) {
244	QE_t *q = list_entry(l, QE_t, list);
245	if (q->SCpnt->device->id == target)
246	__queue_remove(queue, l);
247	}
248	spin_unlock_irqrestore(&queue->queue_lock, flags);
249	}
250
251	/*
252	* Function: int queue_probetgtlun (queue, target, lun)
253	* Purpose : check to see if we have a command in the queue for the specified
254	* target/lun.
255	* Params : queue - queue to look in
256	* target - target we want to probe
257	* lun - lun on target
258	* Returns : 0 if not found, != 0 if found
259	*/
260	int queue_probetgtlun (Queue_t *queue, int target, int lun)
261	{
262	unsigned long flags;
263	struct list_head *l;
264	int found = 0;
265
266	spin_lock_irqsave(&queue->queue_lock, flags);
267	list_for_each(l, &queue->head) {
268	QE_t *q = list_entry(l, QE_t, list);
269	if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun) {
270	found = 1;
271	break;
272	}
273	}
274	spin_unlock_irqrestore(&queue->queue_lock, flags);
275
276	return found;
277	}
278
279	/*
280	* Function: int queue_remove_cmd(Queue_t queue, Scsi_Cmnd SCpnt)
281	* Purpose : remove a specific command from the queues
282	* Params : queue - queue to look in
283	* SCpnt - command to find
284	* Returns : 0 if not found
285	*/
286	int queue_remove_cmd(Queue_t queue, Scsi_Cmnd SCpnt)
287	{
288	unsigned long flags;
289	struct list_head *l;
290	int found = 0;
291
292	spin_lock_irqsave(&queue->queue_lock, flags);
293	list_for_each(l, &queue->head) {
294	QE_t *q = list_entry(l, QE_t, list);
295	if (q->SCpnt == SCpnt) {
296	__queue_remove(queue, l);
297	found = 1;
298	break;
299	}
300	}
301	spin_unlock_irqrestore(&queue->queue_lock, flags);
302
303	return found;
304	}
305
306	EXPORT_SYMBOL(queue_initialise);
307	EXPORT_SYMBOL(queue_free);
308	EXPORT_SYMBOL(__queue_add);
309	EXPORT_SYMBOL(queue_remove);
310	EXPORT_SYMBOL(queue_remove_exclude);
311	EXPORT_SYMBOL(queue_remove_tgtluntag);
312	EXPORT_SYMBOL(queue_remove_cmd);
313	EXPORT_SYMBOL(queue_remove_all_target);
314	EXPORT_SYMBOL(queue_probetgtlun);
315
316	MODULE_AUTHOR("Russell King");
317	MODULE_DESCRIPTION("SCSI command queueing");
318	MODULE_LICENSE("GPL");