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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 <linux/sched/signal.h>
25
26#include "seq_fifo.h"
27#include "seq_lock.h"
28
29
30/* FIFO */
31
32/* create new fifo */
33struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
34{
35 struct snd_seq_fifo *f;
36
37 f = kzalloc(sizeof(*f), GFP_KERNEL);
38 if (!f)
39 return NULL;
40
41 f->pool = snd_seq_pool_new(poolsize);
42 if (f->pool == NULL) {
43 kfree(f);
44 return NULL;
45 }
46 if (snd_seq_pool_init(f->pool) < 0) {
47 snd_seq_pool_delete(&f->pool);
48 kfree(f);
49 return NULL;
50 }
51
52 spin_lock_init(&f->lock);
53 snd_use_lock_init(&f->use_lock);
54 init_waitqueue_head(&f->input_sleep);
55 atomic_set(&f->overflow, 0);
56
57 f->head = NULL;
58 f->tail = NULL;
59 f->cells = 0;
60
61 return f;
62}
63
64void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
65{
66 struct snd_seq_fifo *f;
67
68 if (snd_BUG_ON(!fifo))
69 return;
70 f = *fifo;
71 if (snd_BUG_ON(!f))
72 return;
73 *fifo = NULL;
74
75 if (f->pool)
76 snd_seq_pool_mark_closing(f->pool);
77
78 snd_seq_fifo_clear(f);
79
80 /* wake up clients if any */
81 if (waitqueue_active(&f->input_sleep))
82 wake_up(&f->input_sleep);
83
84 /* release resources...*/
85 /*....................*/
86
87 if (f->pool) {
88 snd_seq_pool_done(f->pool);
89 snd_seq_pool_delete(&f->pool);
90 }
91
92 kfree(f);
93}
94
95static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
96
97/* clear queue */
98void snd_seq_fifo_clear(struct snd_seq_fifo *f)
99{
100 struct snd_seq_event_cell *cell;
101 unsigned long flags;
102
103 /* clear overflow flag */
104 atomic_set(&f->overflow, 0);
105
106 snd_use_lock_sync(&f->use_lock);
107 spin_lock_irqsave(&f->lock, flags);
108 /* drain the fifo */
109 while ((cell = fifo_cell_out(f)) != NULL) {
110 snd_seq_cell_free(cell);
111 }
112 spin_unlock_irqrestore(&f->lock, flags);
113}
114
115
116/* enqueue event to fifo */
117int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
118 struct snd_seq_event *event)
119{
120 struct snd_seq_event_cell *cell;
121 unsigned long flags;
122 int err;
123
124 if (snd_BUG_ON(!f))
125 return -EINVAL;
126
127 snd_use_lock_use(&f->use_lock);
128 err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
129 if (err < 0) {
130 if ((err == -ENOMEM) || (err == -EAGAIN))
131 atomic_inc(&f->overflow);
132 snd_use_lock_free(&f->use_lock);
133 return err;
134 }
135
136 /* append new cells to fifo */
137 spin_lock_irqsave(&f->lock, flags);
138 if (f->tail != NULL)
139 f->tail->next = cell;
140 f->tail = cell;
141 if (f->head == NULL)
142 f->head = cell;
143 cell->next = NULL;
144 f->cells++;
145 spin_unlock_irqrestore(&f->lock, flags);
146
147 /* wakeup client */
148 if (waitqueue_active(&f->input_sleep))
149 wake_up(&f->input_sleep);
150
151 snd_use_lock_free(&f->use_lock);
152
153 return 0; /* success */
154
155}
156
157/* dequeue cell from fifo */
158static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
159{
160 struct snd_seq_event_cell *cell;
161
162 if ((cell = f->head) != NULL) {
163 f->head = cell->next;
164
165 /* reset tail if this was the last element */
166 if (f->tail == cell)
167 f->tail = NULL;
168
169 cell->next = NULL;
170 f->cells--;
171 }
172
173 return cell;
174}
175
176/* dequeue cell from fifo and copy on user space */
177int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
178 struct snd_seq_event_cell **cellp, int nonblock)
179{
180 struct snd_seq_event_cell *cell;
181 unsigned long flags;
182 wait_queue_entry_t wait;
183
184 if (snd_BUG_ON(!f))
185 return -EINVAL;
186
187 *cellp = NULL;
188 init_waitqueue_entry(&wait, current);
189 spin_lock_irqsave(&f->lock, flags);
190 while ((cell = fifo_cell_out(f)) == NULL) {
191 if (nonblock) {
192 /* non-blocking - return immediately */
193 spin_unlock_irqrestore(&f->lock, flags);
194 return -EAGAIN;
195 }
196 set_current_state(TASK_INTERRUPTIBLE);
197 add_wait_queue(&f->input_sleep, &wait);
198 spin_unlock_irq(&f->lock);
199 schedule();
200 spin_lock_irq(&f->lock);
201 remove_wait_queue(&f->input_sleep, &wait);
202 if (signal_pending(current)) {
203 spin_unlock_irqrestore(&f->lock, flags);
204 return -ERESTARTSYS;
205 }
206 }
207 spin_unlock_irqrestore(&f->lock, flags);
208 *cellp = cell;
209
210 return 0;
211}
212
213
214void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
215 struct snd_seq_event_cell *cell)
216{
217 unsigned long flags;
218
219 if (cell) {
220 spin_lock_irqsave(&f->lock, flags);
221 cell->next = f->head;
222 f->head = cell;
223 if (!f->tail)
224 f->tail = cell;
225 f->cells++;
226 spin_unlock_irqrestore(&f->lock, flags);
227 }
228}
229
230
231/* polling; return non-zero if queue is available */
232int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
233 poll_table *wait)
234{
235 poll_wait(file, &f->input_sleep, wait);
236 return (f->cells > 0);
237}
238
239/* change the size of pool; all old events are removed */
240int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
241{
242 unsigned long flags;
243 struct snd_seq_pool *newpool, *oldpool;
244 struct snd_seq_event_cell *cell, *next, *oldhead;
245
246 if (snd_BUG_ON(!f || !f->pool))
247 return -EINVAL;
248
249 /* allocate new pool */
250 newpool = snd_seq_pool_new(poolsize);
251 if (newpool == NULL)
252 return -ENOMEM;
253 if (snd_seq_pool_init(newpool) < 0) {
254 snd_seq_pool_delete(&newpool);
255 return -ENOMEM;
256 }
257
258 spin_lock_irqsave(&f->lock, flags);
259 /* remember old pool */
260 oldpool = f->pool;
261 oldhead = f->head;
262 /* exchange pools */
263 f->pool = newpool;
264 f->head = NULL;
265 f->tail = NULL;
266 f->cells = 0;
267 /* NOTE: overflow flag is not cleared */
268 spin_unlock_irqrestore(&f->lock, flags);
269
270 /* close the old pool and wait until all users are gone */
271 snd_seq_pool_mark_closing(oldpool);
272 snd_use_lock_sync(&f->use_lock);
273
274 /* release cells in old pool */
275 for (cell = oldhead; cell; cell = next) {
276 next = cell->next;
277 snd_seq_cell_free(cell);
278 }
279 snd_seq_pool_delete(&oldpool);
280
281 return 0;
282}