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