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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ALSA sequencer FIFO
4 * Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
5 */
6
7#include <sound/core.h>
8#include <linux/slab.h>
9#include <linux/sched/signal.h>
10
11#include "seq_fifo.h"
12#include "seq_lock.h"
13
14
15/* FIFO */
16
17/* create new fifo */
18struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
19{
20 struct snd_seq_fifo *f;
21
22 f = kzalloc(sizeof(*f), GFP_KERNEL);
23 if (!f)
24 return NULL;
25
26 f->pool = snd_seq_pool_new(poolsize);
27 if (f->pool == NULL) {
28 kfree(f);
29 return NULL;
30 }
31 if (snd_seq_pool_init(f->pool) < 0) {
32 snd_seq_pool_delete(&f->pool);
33 kfree(f);
34 return NULL;
35 }
36
37 spin_lock_init(&f->lock);
38 snd_use_lock_init(&f->use_lock);
39 init_waitqueue_head(&f->input_sleep);
40 atomic_set(&f->overflow, 0);
41
42 f->head = NULL;
43 f->tail = NULL;
44 f->cells = 0;
45
46 return f;
47}
48
49void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
50{
51 struct snd_seq_fifo *f;
52
53 if (snd_BUG_ON(!fifo))
54 return;
55 f = *fifo;
56 if (snd_BUG_ON(!f))
57 return;
58 *fifo = NULL;
59
60 if (f->pool)
61 snd_seq_pool_mark_closing(f->pool);
62
63 snd_seq_fifo_clear(f);
64
65 /* wake up clients if any */
66 if (waitqueue_active(&f->input_sleep))
67 wake_up(&f->input_sleep);
68
69 /* release resources...*/
70 /*....................*/
71
72 if (f->pool) {
73 snd_seq_pool_done(f->pool);
74 snd_seq_pool_delete(&f->pool);
75 }
76
77 kfree(f);
78}
79
80static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
81
82/* clear queue */
83void snd_seq_fifo_clear(struct snd_seq_fifo *f)
84{
85 struct snd_seq_event_cell *cell;
86
87 /* clear overflow flag */
88 atomic_set(&f->overflow, 0);
89
90 snd_use_lock_sync(&f->use_lock);
91 spin_lock_irq(&f->lock);
92 /* drain the fifo */
93 while ((cell = fifo_cell_out(f)) != NULL) {
94 snd_seq_cell_free(cell);
95 }
96 spin_unlock_irq(&f->lock);
97}
98
99
100/* enqueue event to fifo */
101int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
102 struct snd_seq_event *event)
103{
104 struct snd_seq_event_cell *cell;
105 unsigned long flags;
106 int err;
107
108 if (snd_BUG_ON(!f))
109 return -EINVAL;
110
111 snd_use_lock_use(&f->use_lock);
112 err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
113 if (err < 0) {
114 if ((err == -ENOMEM) || (err == -EAGAIN))
115 atomic_inc(&f->overflow);
116 snd_use_lock_free(&f->use_lock);
117 return err;
118 }
119
120 /* append new cells to fifo */
121 spin_lock_irqsave(&f->lock, flags);
122 if (f->tail != NULL)
123 f->tail->next = cell;
124 f->tail = cell;
125 if (f->head == NULL)
126 f->head = cell;
127 cell->next = NULL;
128 f->cells++;
129 spin_unlock_irqrestore(&f->lock, flags);
130
131 /* wakeup client */
132 if (waitqueue_active(&f->input_sleep))
133 wake_up(&f->input_sleep);
134
135 snd_use_lock_free(&f->use_lock);
136
137 return 0; /* success */
138
139}
140
141/* dequeue cell from fifo */
142static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
143{
144 struct snd_seq_event_cell *cell;
145
146 if ((cell = f->head) != NULL) {
147 f->head = cell->next;
148
149 /* reset tail if this was the last element */
150 if (f->tail == cell)
151 f->tail = NULL;
152
153 cell->next = NULL;
154 f->cells--;
155 }
156
157 return cell;
158}
159
160/* dequeue cell from fifo and copy on user space */
161int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
162 struct snd_seq_event_cell **cellp, int nonblock)
163{
164 struct snd_seq_event_cell *cell;
165 unsigned long flags;
166 wait_queue_entry_t wait;
167
168 if (snd_BUG_ON(!f))
169 return -EINVAL;
170
171 *cellp = NULL;
172 init_waitqueue_entry(&wait, current);
173 spin_lock_irqsave(&f->lock, flags);
174 while ((cell = fifo_cell_out(f)) == NULL) {
175 if (nonblock) {
176 /* non-blocking - return immediately */
177 spin_unlock_irqrestore(&f->lock, flags);
178 return -EAGAIN;
179 }
180 set_current_state(TASK_INTERRUPTIBLE);
181 add_wait_queue(&f->input_sleep, &wait);
182 spin_unlock_irqrestore(&f->lock, flags);
183 schedule();
184 spin_lock_irqsave(&f->lock, flags);
185 remove_wait_queue(&f->input_sleep, &wait);
186 if (signal_pending(current)) {
187 spin_unlock_irqrestore(&f->lock, flags);
188 return -ERESTARTSYS;
189 }
190 }
191 spin_unlock_irqrestore(&f->lock, flags);
192 *cellp = cell;
193
194 return 0;
195}
196
197
198void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
199 struct snd_seq_event_cell *cell)
200{
201 unsigned long flags;
202
203 if (cell) {
204 spin_lock_irqsave(&f->lock, flags);
205 cell->next = f->head;
206 f->head = cell;
207 if (!f->tail)
208 f->tail = cell;
209 f->cells++;
210 spin_unlock_irqrestore(&f->lock, flags);
211 }
212}
213
214
215/* polling; return non-zero if queue is available */
216int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
217 poll_table *wait)
218{
219 poll_wait(file, &f->input_sleep, wait);
220 return (f->cells > 0);
221}
222
223/* change the size of pool; all old events are removed */
224int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
225{
226 struct snd_seq_pool *newpool, *oldpool;
227 struct snd_seq_event_cell *cell, *next, *oldhead;
228
229 if (snd_BUG_ON(!f || !f->pool))
230 return -EINVAL;
231
232 /* allocate new pool */
233 newpool = snd_seq_pool_new(poolsize);
234 if (newpool == NULL)
235 return -ENOMEM;
236 if (snd_seq_pool_init(newpool) < 0) {
237 snd_seq_pool_delete(&newpool);
238 return -ENOMEM;
239 }
240
241 spin_lock_irq(&f->lock);
242 /* remember old pool */
243 oldpool = f->pool;
244 oldhead = f->head;
245 /* exchange pools */
246 f->pool = newpool;
247 f->head = NULL;
248 f->tail = NULL;
249 f->cells = 0;
250 /* NOTE: overflow flag is not cleared */
251 spin_unlock_irq(&f->lock);
252
253 /* close the old pool and wait until all users are gone */
254 snd_seq_pool_mark_closing(oldpool);
255 snd_use_lock_sync(&f->use_lock);
256
257 /* release cells in old pool */
258 for (cell = oldhead; cell; cell = next) {
259 next = cell->next;
260 snd_seq_cell_free(cell);
261 }
262 snd_seq_pool_delete(&oldpool);
263
264 return 0;
265}
266
267/* get the number of unused cells safely */
268int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f)
269{
270 unsigned long flags;
271 int cells;
272
273 if (!f)
274 return 0;
275
276 snd_use_lock_use(&f->use_lock);
277 spin_lock_irqsave(&f->lock, flags);
278 cells = snd_seq_unused_cells(f->pool);
279 spin_unlock_irqrestore(&f->lock, flags);
280 snd_use_lock_free(&f->use_lock);
281 return cells;
282}
1/*
2 * ALSA sequencer FIFO
3 * Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
4 *
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 as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21
22#include <sound/core.h>
23#include <linux/slab.h>
24#include "seq_fifo.h"
25#include "seq_lock.h"
26
27
28/* FIFO */
29
30/* create new fifo */
31struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
32{
33 struct snd_seq_fifo *f;
34
35 f = kzalloc(sizeof(*f), GFP_KERNEL);
36 if (!f)
37 return NULL;
38
39 f->pool = snd_seq_pool_new(poolsize);
40 if (f->pool == NULL) {
41 kfree(f);
42 return NULL;
43 }
44 if (snd_seq_pool_init(f->pool) < 0) {
45 snd_seq_pool_delete(&f->pool);
46 kfree(f);
47 return NULL;
48 }
49
50 spin_lock_init(&f->lock);
51 snd_use_lock_init(&f->use_lock);
52 init_waitqueue_head(&f->input_sleep);
53 atomic_set(&f->overflow, 0);
54
55 f->head = NULL;
56 f->tail = NULL;
57 f->cells = 0;
58
59 return f;
60}
61
62void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
63{
64 struct snd_seq_fifo *f;
65
66 if (snd_BUG_ON(!fifo))
67 return;
68 f = *fifo;
69 if (snd_BUG_ON(!f))
70 return;
71 *fifo = NULL;
72
73 snd_seq_fifo_clear(f);
74
75 /* wake up clients if any */
76 if (waitqueue_active(&f->input_sleep))
77 wake_up(&f->input_sleep);
78
79 /* release resources...*/
80 /*....................*/
81
82 if (f->pool) {
83 snd_seq_pool_done(f->pool);
84 snd_seq_pool_delete(&f->pool);
85 }
86
87 kfree(f);
88}
89
90static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
91
92/* clear queue */
93void snd_seq_fifo_clear(struct snd_seq_fifo *f)
94{
95 struct snd_seq_event_cell *cell;
96 unsigned long flags;
97
98 /* clear overflow flag */
99 atomic_set(&f->overflow, 0);
100
101 snd_use_lock_sync(&f->use_lock);
102 spin_lock_irqsave(&f->lock, flags);
103 /* drain the fifo */
104 while ((cell = fifo_cell_out(f)) != NULL) {
105 snd_seq_cell_free(cell);
106 }
107 spin_unlock_irqrestore(&f->lock, flags);
108}
109
110
111/* enqueue event to fifo */
112int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
113 struct snd_seq_event *event)
114{
115 struct snd_seq_event_cell *cell;
116 unsigned long flags;
117 int err;
118
119 if (snd_BUG_ON(!f))
120 return -EINVAL;
121
122 snd_use_lock_use(&f->use_lock);
123 err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
124 if (err < 0) {
125 if ((err == -ENOMEM) || (err == -EAGAIN))
126 atomic_inc(&f->overflow);
127 snd_use_lock_free(&f->use_lock);
128 return err;
129 }
130
131 /* append new cells to fifo */
132 spin_lock_irqsave(&f->lock, flags);
133 if (f->tail != NULL)
134 f->tail->next = cell;
135 f->tail = cell;
136 if (f->head == NULL)
137 f->head = cell;
138 f->cells++;
139 spin_unlock_irqrestore(&f->lock, flags);
140
141 /* wakeup client */
142 if (waitqueue_active(&f->input_sleep))
143 wake_up(&f->input_sleep);
144
145 snd_use_lock_free(&f->use_lock);
146
147 return 0; /* success */
148
149}
150
151/* dequeue cell from fifo */
152static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
153{
154 struct snd_seq_event_cell *cell;
155
156 if ((cell = f->head) != NULL) {
157 f->head = cell->next;
158
159 /* reset tail if this was the last element */
160 if (f->tail == cell)
161 f->tail = NULL;
162
163 cell->next = NULL;
164 f->cells--;
165 }
166
167 return cell;
168}
169
170/* dequeue cell from fifo and copy on user space */
171int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
172 struct snd_seq_event_cell **cellp, int nonblock)
173{
174 struct snd_seq_event_cell *cell;
175 unsigned long flags;
176 wait_queue_t wait;
177
178 if (snd_BUG_ON(!f))
179 return -EINVAL;
180
181 *cellp = NULL;
182 init_waitqueue_entry(&wait, current);
183 spin_lock_irqsave(&f->lock, flags);
184 while ((cell = fifo_cell_out(f)) == NULL) {
185 if (nonblock) {
186 /* non-blocking - return immediately */
187 spin_unlock_irqrestore(&f->lock, flags);
188 return -EAGAIN;
189 }
190 set_current_state(TASK_INTERRUPTIBLE);
191 add_wait_queue(&f->input_sleep, &wait);
192 spin_unlock_irq(&f->lock);
193 schedule();
194 spin_lock_irq(&f->lock);
195 remove_wait_queue(&f->input_sleep, &wait);
196 if (signal_pending(current)) {
197 spin_unlock_irqrestore(&f->lock, flags);
198 return -ERESTARTSYS;
199 }
200 }
201 spin_unlock_irqrestore(&f->lock, flags);
202 *cellp = cell;
203
204 return 0;
205}
206
207
208void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
209 struct snd_seq_event_cell *cell)
210{
211 unsigned long flags;
212
213 if (cell) {
214 spin_lock_irqsave(&f->lock, flags);
215 cell->next = f->head;
216 f->head = cell;
217 f->cells++;
218 spin_unlock_irqrestore(&f->lock, flags);
219 }
220}
221
222
223/* polling; return non-zero if queue is available */
224int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
225 poll_table *wait)
226{
227 poll_wait(file, &f->input_sleep, wait);
228 return (f->cells > 0);
229}
230
231/* change the size of pool; all old events are removed */
232int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
233{
234 unsigned long flags;
235 struct snd_seq_pool *newpool, *oldpool;
236 struct snd_seq_event_cell *cell, *next, *oldhead;
237
238 if (snd_BUG_ON(!f || !f->pool))
239 return -EINVAL;
240
241 /* allocate new pool */
242 newpool = snd_seq_pool_new(poolsize);
243 if (newpool == NULL)
244 return -ENOMEM;
245 if (snd_seq_pool_init(newpool) < 0) {
246 snd_seq_pool_delete(&newpool);
247 return -ENOMEM;
248 }
249
250 spin_lock_irqsave(&f->lock, flags);
251 /* remember old pool */
252 oldpool = f->pool;
253 oldhead = f->head;
254 /* exchange pools */
255 f->pool = newpool;
256 f->head = NULL;
257 f->tail = NULL;
258 f->cells = 0;
259 /* NOTE: overflow flag is not cleared */
260 spin_unlock_irqrestore(&f->lock, flags);
261
262 /* release cells in old pool */
263 for (cell = oldhead; cell; cell = next) {
264 next = cell->next;
265 snd_seq_cell_free(cell);
266 }
267 snd_seq_pool_delete(&oldpool);
268
269 return 0;
270}