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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
30typedef struct queue_entry {
31 struct list_head list;
32 struct 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 */
58int 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 */
90void queue_free (Queue_t *queue)
91{
92 if (!list_empty(&queue->head))
93 printk(KERN_WARNING "freeing non-empty queue %p\n", queue);
94 kfree(queue->alloc);
95}
96
97
98/*
99 * Function: int __queue_add(Queue_t *queue, struct 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 */
106int __queue_add(Queue_t *queue, struct 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 BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_FREE));
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;
132empty:
133 spin_unlock_irqrestore(&queue->queue_lock, flags);
134 return ret;
135}
136
137static struct scsi_cmnd *__queue_remove(Queue_t *queue, struct list_head *ent)
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);
146 BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_USED));
147
148 SET_MAGIC(q, QUEUE_MAGIC_FREE);
149 list_add(ent, &queue->free);
150
151 return q->SCpnt;
152}
153
154/*
155 * Function: struct scsi_cmnd *queue_remove_exclude (queue, exclude)
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
159 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
160 */
161struct scsi_cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude)
162{
163 unsigned long flags;
164 struct list_head *l;
165 struct scsi_cmnd *SCpnt = NULL;
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/*
181 * Function: struct scsi_cmnd *queue_remove (queue)
182 * Purpose : removes first SCSI command from a queue
183 * Params : queue - queue to remove command from
184 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
185 */
186struct scsi_cmnd *queue_remove(Queue_t *queue)
187{
188 unsigned long flags;
189 struct scsi_cmnd *SCpnt = NULL;
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/*
200 * Function: struct scsi_cmnd *queue_remove_tgtluntag (queue, target, lun, tag)
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
206 * Returns : struct scsi_cmnd if successful, or NULL if no command satisfies requirements
207 */
208struct scsi_cmnd *queue_remove_tgtluntag(Queue_t *queue, int target, int lun,
209 int tag)
210{
211 unsigned long flags;
212 struct list_head *l;
213 struct scsi_cmnd *SCpnt = NULL;
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 */
236void 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 */
259int 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/*
279 * Function: int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
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 */
285int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
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
305EXPORT_SYMBOL(queue_initialise);
306EXPORT_SYMBOL(queue_free);
307EXPORT_SYMBOL(__queue_add);
308EXPORT_SYMBOL(queue_remove);
309EXPORT_SYMBOL(queue_remove_exclude);
310EXPORT_SYMBOL(queue_remove_tgtluntag);
311EXPORT_SYMBOL(queue_remove_cmd);
312EXPORT_SYMBOL(queue_remove_all_target);
313EXPORT_SYMBOL(queue_probetgtlun);
314
315MODULE_AUTHOR("Russell King");
316MODULE_DESCRIPTION("SCSI command queueing");
317MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/acorn/scsi/queue.c: queue handling primitives
4 *
5 * Copyright (C) 1997-2000 Russell King
6 *
7 * Changelog:
8 * 15-Sep-1997 RMK Created.
9 * 11-Oct-1997 RMK Corrected problem with queue_remove_exclude
10 * not updating internal linked list properly
11 * (was causing commands to go missing).
12 * 30-Aug-2000 RMK Use Linux list handling and spinlocks
13 */
14#include <linux/module.h>
15#include <linux/blkdev.h>
16#include <linux/kernel.h>
17#include <linux/string.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20#include <linux/list.h>
21#include <linux/init.h>
22
23#include "../scsi.h"
24
25#define DEBUG
26
27typedef struct queue_entry {
28 struct list_head list;
29 struct scsi_cmnd *SCpnt;
30#ifdef DEBUG
31 unsigned long magic;
32#endif
33} QE_t;
34
35#ifdef DEBUG
36#define QUEUE_MAGIC_FREE 0xf7e1c9a3
37#define QUEUE_MAGIC_USED 0xf7e1cc33
38
39#define SET_MAGIC(q,m) ((q)->magic = (m))
40#define BAD_MAGIC(q,m) ((q)->magic != (m))
41#else
42#define SET_MAGIC(q,m) do { } while (0)
43#define BAD_MAGIC(q,m) (0)
44#endif
45
46#include "queue.h"
47
48#define NR_QE 32
49
50/*
51 * Function: void queue_initialise (Queue_t *queue)
52 * Purpose : initialise a queue
53 * Params : queue - queue to initialise
54 */
55int queue_initialise (Queue_t *queue)
56{
57 unsigned int nqueues = NR_QE;
58 QE_t *q;
59
60 spin_lock_init(&queue->queue_lock);
61 INIT_LIST_HEAD(&queue->head);
62 INIT_LIST_HEAD(&queue->free);
63
64 /*
65 * If life was easier, then SCpnt would have a
66 * host-available list head, and we wouldn't
67 * need to keep free lists or allocate this
68 * memory.
69 */
70 queue->alloc = q = kmalloc_array(nqueues, sizeof(QE_t), GFP_KERNEL);
71 if (q) {
72 for (; nqueues; q++, nqueues--) {
73 SET_MAGIC(q, QUEUE_MAGIC_FREE);
74 q->SCpnt = NULL;
75 list_add(&q->list, &queue->free);
76 }
77 }
78
79 return queue->alloc != NULL;
80}
81
82/*
83 * Function: void queue_free (Queue_t *queue)
84 * Purpose : free a queue
85 * Params : queue - queue to free
86 */
87void queue_free (Queue_t *queue)
88{
89 if (!list_empty(&queue->head))
90 printk(KERN_WARNING "freeing non-empty queue %p\n", queue);
91 kfree(queue->alloc);
92}
93
94
95/*
96 * Function: int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head)
97 * Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
98 * Params : queue - destination queue
99 * SCpnt - command to add
100 * head - add command to head of queue
101 * Returns : 0 on error, !0 on success
102 */
103int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head)
104{
105 unsigned long flags;
106 struct list_head *l;
107 QE_t *q;
108 int ret = 0;
109
110 spin_lock_irqsave(&queue->queue_lock, flags);
111 if (list_empty(&queue->free))
112 goto empty;
113
114 l = queue->free.next;
115 list_del(l);
116
117 q = list_entry(l, QE_t, list);
118 BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_FREE));
119
120 SET_MAGIC(q, QUEUE_MAGIC_USED);
121 q->SCpnt = SCpnt;
122
123 if (head)
124 list_add(l, &queue->head);
125 else
126 list_add_tail(l, &queue->head);
127
128 ret = 1;
129empty:
130 spin_unlock_irqrestore(&queue->queue_lock, flags);
131 return ret;
132}
133
134static struct scsi_cmnd *__queue_remove(Queue_t *queue, struct list_head *ent)
135{
136 QE_t *q;
137
138 /*
139 * Move the entry from the "used" list onto the "free" list
140 */
141 list_del(ent);
142 q = list_entry(ent, QE_t, list);
143 BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_USED));
144
145 SET_MAGIC(q, QUEUE_MAGIC_FREE);
146 list_add(ent, &queue->free);
147
148 return q->SCpnt;
149}
150
151/*
152 * Function: struct scsi_cmnd *queue_remove_exclude (queue, exclude)
153 * Purpose : remove a SCSI command from a queue
154 * Params : queue - queue to remove command from
155 * exclude - bit array of target&lun which is busy
156 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
157 */
158struct scsi_cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude)
159{
160 unsigned long flags;
161 struct list_head *l;
162 struct scsi_cmnd *SCpnt = NULL;
163
164 spin_lock_irqsave(&queue->queue_lock, flags);
165 list_for_each(l, &queue->head) {
166 QE_t *q = list_entry(l, QE_t, list);
167 if (!test_bit(q->SCpnt->device->id * 8 +
168 (u8)(q->SCpnt->device->lun & 0x7), exclude)) {
169 SCpnt = __queue_remove(queue, l);
170 break;
171 }
172 }
173 spin_unlock_irqrestore(&queue->queue_lock, flags);
174
175 return SCpnt;
176}
177
178/*
179 * Function: struct scsi_cmnd *queue_remove (queue)
180 * Purpose : removes first SCSI command from a queue
181 * Params : queue - queue to remove command from
182 * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available
183 */
184struct scsi_cmnd *queue_remove(Queue_t *queue)
185{
186 unsigned long flags;
187 struct scsi_cmnd *SCpnt = NULL;
188
189 spin_lock_irqsave(&queue->queue_lock, flags);
190 if (!list_empty(&queue->head))
191 SCpnt = __queue_remove(queue, queue->head.next);
192 spin_unlock_irqrestore(&queue->queue_lock, flags);
193
194 return SCpnt;
195}
196
197/*
198 * Function: struct scsi_cmnd *queue_remove_tgtluntag (queue, target, lun, tag)
199 * Purpose : remove a SCSI command from the queue for a specified target/lun/tag
200 * Params : queue - queue to remove command from
201 * target - target that we want
202 * lun - lun on device
203 * tag - tag on device
204 * Returns : struct scsi_cmnd if successful, or NULL if no command satisfies requirements
205 */
206struct scsi_cmnd *queue_remove_tgtluntag(Queue_t *queue, int target, int lun,
207 int tag)
208{
209 unsigned long flags;
210 struct list_head *l;
211 struct scsi_cmnd *SCpnt = NULL;
212
213 spin_lock_irqsave(&queue->queue_lock, flags);
214 list_for_each(l, &queue->head) {
215 QE_t *q = list_entry(l, QE_t, list);
216 if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun &&
217 q->SCpnt->tag == tag) {
218 SCpnt = __queue_remove(queue, l);
219 break;
220 }
221 }
222 spin_unlock_irqrestore(&queue->queue_lock, flags);
223
224 return SCpnt;
225}
226
227/*
228 * Function: queue_remove_all_target(queue, target)
229 * Purpose : remove all SCSI commands from the queue for a specified target
230 * Params : queue - queue to remove command from
231 * target - target device id
232 * Returns : nothing
233 */
234void queue_remove_all_target(Queue_t *queue, int target)
235{
236 unsigned long flags;
237 struct list_head *l;
238
239 spin_lock_irqsave(&queue->queue_lock, flags);
240 list_for_each(l, &queue->head) {
241 QE_t *q = list_entry(l, QE_t, list);
242 if (q->SCpnt->device->id == target)
243 __queue_remove(queue, l);
244 }
245 spin_unlock_irqrestore(&queue->queue_lock, flags);
246}
247
248/*
249 * Function: int queue_probetgtlun (queue, target, lun)
250 * Purpose : check to see if we have a command in the queue for the specified
251 * target/lun.
252 * Params : queue - queue to look in
253 * target - target we want to probe
254 * lun - lun on target
255 * Returns : 0 if not found, != 0 if found
256 */
257int queue_probetgtlun (Queue_t *queue, int target, int lun)
258{
259 unsigned long flags;
260 struct list_head *l;
261 int found = 0;
262
263 spin_lock_irqsave(&queue->queue_lock, flags);
264 list_for_each(l, &queue->head) {
265 QE_t *q = list_entry(l, QE_t, list);
266 if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun) {
267 found = 1;
268 break;
269 }
270 }
271 spin_unlock_irqrestore(&queue->queue_lock, flags);
272
273 return found;
274}
275
276/*
277 * Function: int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
278 * Purpose : remove a specific command from the queues
279 * Params : queue - queue to look in
280 * SCpnt - command to find
281 * Returns : 0 if not found
282 */
283int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt)
284{
285 unsigned long flags;
286 struct list_head *l;
287 int found = 0;
288
289 spin_lock_irqsave(&queue->queue_lock, flags);
290 list_for_each(l, &queue->head) {
291 QE_t *q = list_entry(l, QE_t, list);
292 if (q->SCpnt == SCpnt) {
293 __queue_remove(queue, l);
294 found = 1;
295 break;
296 }
297 }
298 spin_unlock_irqrestore(&queue->queue_lock, flags);
299
300 return found;
301}
302
303EXPORT_SYMBOL(queue_initialise);
304EXPORT_SYMBOL(queue_free);
305EXPORT_SYMBOL(__queue_add);
306EXPORT_SYMBOL(queue_remove);
307EXPORT_SYMBOL(queue_remove_exclude);
308EXPORT_SYMBOL(queue_remove_tgtluntag);
309EXPORT_SYMBOL(queue_remove_cmd);
310EXPORT_SYMBOL(queue_remove_all_target);
311EXPORT_SYMBOL(queue_probetgtlun);
312
313MODULE_AUTHOR("Russell King");
314MODULE_DESCRIPTION("SCSI command queueing");
315MODULE_LICENSE("GPL");