Commit | Line | Data |
---|---|---|
e0495736 AC |
1 | /* |
2 | * Tty buffer allocation management | |
3 | */ | |
4 | ||
5 | #include <linux/types.h> | |
6 | #include <linux/errno.h> | |
7 | #include <linux/tty.h> | |
8 | #include <linux/tty_driver.h> | |
9 | #include <linux/tty_flip.h> | |
10 | #include <linux/timer.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/wait.h> | |
16 | #include <linux/bitops.h> | |
17 | #include <linux/delay.h> | |
18 | #include <linux/module.h> | |
593fb1ae | 19 | #include <linux/ratelimit.h> |
e0495736 | 20 | |
1cef50e3 PH |
21 | |
22 | #define MIN_TTYB_SIZE 256 | |
23 | #define TTYB_ALIGN_MASK 255 | |
24 | ||
9dd5139f PH |
25 | static void tty_buffer_reset(struct tty_buffer *p, size_t size) |
26 | { | |
27 | p->used = 0; | |
28 | p->size = size; | |
29 | p->next = NULL; | |
30 | p->commit = 0; | |
31 | p->read = 0; | |
32 | } | |
33 | ||
e0495736 AC |
34 | /** |
35 | * tty_buffer_free_all - free buffers used by a tty | |
36 | * @tty: tty to free from | |
37 | * | |
38 | * Remove all the buffers pending on a tty whether queued with data | |
39 | * or in the free ring. Must be called when the tty is no longer in use | |
40 | * | |
41 | * Locking: none | |
42 | */ | |
43 | ||
ecbbfd44 | 44 | void tty_buffer_free_all(struct tty_port *port) |
e0495736 | 45 | { |
ecbbfd44 | 46 | struct tty_bufhead *buf = &port->buf; |
e0495736 | 47 | struct tty_buffer *thead; |
5cff39c6 JS |
48 | |
49 | while ((thead = buf->head) != NULL) { | |
50 | buf->head = thead->next; | |
e0495736 AC |
51 | kfree(thead); |
52 | } | |
5cff39c6 JS |
53 | while ((thead = buf->free) != NULL) { |
54 | buf->free = thead->next; | |
e0495736 AC |
55 | kfree(thead); |
56 | } | |
5cff39c6 JS |
57 | buf->tail = NULL; |
58 | buf->memory_used = 0; | |
e0495736 AC |
59 | } |
60 | ||
61 | /** | |
62 | * tty_buffer_alloc - allocate a tty buffer | |
63 | * @tty: tty device | |
64 | * @size: desired size (characters) | |
65 | * | |
66 | * Allocate a new tty buffer to hold the desired number of characters. | |
67 | * Return NULL if out of memory or the allocation would exceed the | |
68 | * per device queue | |
69 | * | |
70 | * Locking: Caller must hold tty->buf.lock | |
71 | */ | |
72 | ||
ecbbfd44 | 73 | static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) |
e0495736 AC |
74 | { |
75 | struct tty_buffer *p; | |
76 | ||
ecbbfd44 | 77 | if (port->buf.memory_used + size > 65536) |
e0495736 AC |
78 | return NULL; |
79 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
80 | if (p == NULL) | |
81 | return NULL; | |
9dd5139f PH |
82 | |
83 | tty_buffer_reset(p, size); | |
ecbbfd44 | 84 | port->buf.memory_used += size; |
e0495736 AC |
85 | return p; |
86 | } | |
87 | ||
88 | /** | |
89 | * tty_buffer_free - free a tty buffer | |
90 | * @tty: tty owning the buffer | |
91 | * @b: the buffer to free | |
92 | * | |
93 | * Free a tty buffer, or add it to the free list according to our | |
94 | * internal strategy | |
95 | * | |
96 | * Locking: Caller must hold tty->buf.lock | |
97 | */ | |
98 | ||
ecbbfd44 | 99 | static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b) |
e0495736 | 100 | { |
ecbbfd44 | 101 | struct tty_bufhead *buf = &port->buf; |
5cff39c6 | 102 | |
e0495736 | 103 | /* Dumb strategy for now - should keep some stats */ |
5cff39c6 JS |
104 | buf->memory_used -= b->size; |
105 | WARN_ON(buf->memory_used < 0); | |
e0495736 | 106 | |
1cef50e3 | 107 | if (b->size > MIN_TTYB_SIZE) |
e0495736 AC |
108 | kfree(b); |
109 | else { | |
5cff39c6 JS |
110 | b->next = buf->free; |
111 | buf->free = b; | |
e0495736 AC |
112 | } |
113 | } | |
114 | ||
115 | /** | |
116 | * __tty_buffer_flush - flush full tty buffers | |
117 | * @tty: tty to flush | |
118 | * | |
119 | * flush all the buffers containing receive data. Caller must | |
120 | * hold the buffer lock and must have ensured no parallel flush to | |
121 | * ldisc is running. | |
122 | * | |
123 | * Locking: Caller must hold tty->buf.lock | |
124 | */ | |
125 | ||
ecbbfd44 | 126 | static void __tty_buffer_flush(struct tty_port *port) |
e0495736 | 127 | { |
ecbbfd44 | 128 | struct tty_bufhead *buf = &port->buf; |
e0495736 AC |
129 | struct tty_buffer *thead; |
130 | ||
64325a3b IZ |
131 | if (unlikely(buf->head == NULL)) |
132 | return; | |
133 | while ((thead = buf->head->next) != NULL) { | |
134 | tty_buffer_free(port, buf->head); | |
135 | buf->head = thead; | |
e0495736 | 136 | } |
64325a3b IZ |
137 | WARN_ON(buf->head != buf->tail); |
138 | buf->head->read = buf->head->commit; | |
e0495736 AC |
139 | } |
140 | ||
141 | /** | |
142 | * tty_buffer_flush - flush full tty buffers | |
143 | * @tty: tty to flush | |
144 | * | |
145 | * flush all the buffers containing receive data. If the buffer is | |
146 | * being processed by flush_to_ldisc then we defer the processing | |
147 | * to that function | |
148 | * | |
149 | * Locking: none | |
150 | */ | |
151 | ||
152 | void tty_buffer_flush(struct tty_struct *tty) | |
153 | { | |
2fc20661 | 154 | struct tty_port *port = tty->port; |
ecbbfd44 | 155 | struct tty_bufhead *buf = &port->buf; |
e0495736 | 156 | unsigned long flags; |
5cff39c6 JS |
157 | |
158 | spin_lock_irqsave(&buf->lock, flags); | |
e0495736 AC |
159 | |
160 | /* If the data is being pushed to the tty layer then we can't | |
161 | process it here. Instead set a flag and the flush_to_ldisc | |
162 | path will process the flush request before it exits */ | |
2fc20661 JS |
163 | if (test_bit(TTYP_FLUSHING, &port->iflags)) { |
164 | set_bit(TTYP_FLUSHPENDING, &port->iflags); | |
5cff39c6 | 165 | spin_unlock_irqrestore(&buf->lock, flags); |
e0495736 | 166 | wait_event(tty->read_wait, |
2fc20661 | 167 | test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0); |
e0495736 AC |
168 | return; |
169 | } else | |
ecbbfd44 | 170 | __tty_buffer_flush(port); |
5cff39c6 | 171 | spin_unlock_irqrestore(&buf->lock, flags); |
e0495736 AC |
172 | } |
173 | ||
174 | /** | |
175 | * tty_buffer_find - find a free tty buffer | |
176 | * @tty: tty owning the buffer | |
177 | * @size: characters wanted | |
178 | * | |
179 | * Locate an existing suitable tty buffer or if we are lacking one then | |
180 | * allocate a new one. We round our buffers off in 256 character chunks | |
181 | * to get better allocation behaviour. | |
182 | * | |
183 | * Locking: Caller must hold tty->buf.lock | |
184 | */ | |
185 | ||
ecbbfd44 | 186 | static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size) |
e0495736 | 187 | { |
ecbbfd44 | 188 | struct tty_buffer **tbh = &port->buf.free; |
1cef50e3 PH |
189 | if (size <= MIN_TTYB_SIZE) { |
190 | if (*tbh) { | |
191 | struct tty_buffer *t = *tbh; | |
192 | ||
e0495736 | 193 | *tbh = t->next; |
9dd5139f | 194 | tty_buffer_reset(t, t->size); |
ecbbfd44 | 195 | port->buf.memory_used += t->size; |
e0495736 AC |
196 | return t; |
197 | } | |
e0495736 AC |
198 | } |
199 | /* Round the buffer size out */ | |
1cef50e3 | 200 | size = __ALIGN_MASK(size, TTYB_ALIGN_MASK); |
ecbbfd44 | 201 | return tty_buffer_alloc(port, size); |
e0495736 AC |
202 | /* Should possibly check if this fails for the largest buffer we |
203 | have queued and recycle that ? */ | |
204 | } | |
e0495736 | 205 | /** |
64325a3b | 206 | * tty_buffer_request_room - grow tty buffer if needed |
e0495736 AC |
207 | * @tty: tty structure |
208 | * @size: size desired | |
209 | * | |
210 | * Make at least size bytes of linear space available for the tty | |
211 | * buffer. If we fail return the size we managed to find. | |
64325a3b IZ |
212 | * |
213 | * Locking: Takes port->buf.lock | |
e0495736 | 214 | */ |
64325a3b | 215 | int tty_buffer_request_room(struct tty_port *port, size_t size) |
e0495736 | 216 | { |
ecbbfd44 | 217 | struct tty_bufhead *buf = &port->buf; |
e0495736 AC |
218 | struct tty_buffer *b, *n; |
219 | int left; | |
64325a3b IZ |
220 | unsigned long flags; |
221 | spin_lock_irqsave(&buf->lock, flags); | |
e0495736 AC |
222 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to |
223 | remove this conditional if its worth it. This would be invisible | |
224 | to the callers */ | |
5cff39c6 JS |
225 | b = buf->tail; |
226 | if (b != NULL) | |
e0495736 AC |
227 | left = b->size - b->used; |
228 | else | |
229 | left = 0; | |
230 | ||
231 | if (left < size) { | |
232 | /* This is the slow path - looking for new buffers to use */ | |
ecbbfd44 | 233 | if ((n = tty_buffer_find(port, size)) != NULL) { |
e0495736 AC |
234 | if (b != NULL) { |
235 | b->next = n; | |
236 | b->commit = b->used; | |
237 | } else | |
5cff39c6 JS |
238 | buf->head = n; |
239 | buf->tail = n; | |
e0495736 AC |
240 | } else |
241 | size = left; | |
242 | } | |
64325a3b | 243 | spin_unlock_irqrestore(&buf->lock, flags); |
e0495736 AC |
244 | return size; |
245 | } | |
246 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); | |
247 | ||
248 | /** | |
2832fc11 | 249 | * tty_insert_flip_string_fixed_flag - Add characters to the tty buffer |
2f693357 | 250 | * @port: tty port |
e0495736 | 251 | * @chars: characters |
2832fc11 | 252 | * @flag: flag value for each character |
e0495736 AC |
253 | * @size: size |
254 | * | |
255 | * Queue a series of bytes to the tty buffering. All the characters | |
ccc5ca8d | 256 | * passed are marked with the supplied flag. Returns the number added. |
e0495736 | 257 | * |
ecbbfd44 | 258 | * Locking: Called functions may take port->buf.lock |
e0495736 AC |
259 | */ |
260 | ||
2f693357 | 261 | int tty_insert_flip_string_fixed_flag(struct tty_port *port, |
2832fc11 | 262 | const unsigned char *chars, char flag, size_t size) |
e0495736 AC |
263 | { |
264 | int copied = 0; | |
265 | do { | |
d4bee0a6 | 266 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
64325a3b IZ |
267 | int space = tty_buffer_request_room(port, goal); |
268 | struct tty_buffer *tb = port->buf.tail; | |
e0495736 | 269 | /* If there is no space then tb may be NULL */ |
c56a00a1 | 270 | if (unlikely(space == 0)) { |
e0495736 | 271 | break; |
c56a00a1 | 272 | } |
1fc359fc PH |
273 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
274 | memset(flag_buf_ptr(tb, tb->used), flag, space); | |
e0495736 AC |
275 | tb->used += space; |
276 | copied += space; | |
277 | chars += space; | |
278 | /* There is a small chance that we need to split the data over | |
279 | several buffers. If this is the case we must loop */ | |
280 | } while (unlikely(size > copied)); | |
281 | return copied; | |
282 | } | |
2832fc11 | 283 | EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag); |
e0495736 AC |
284 | |
285 | /** | |
286 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
2f693357 | 287 | * @port: tty port |
e0495736 AC |
288 | * @chars: characters |
289 | * @flags: flag bytes | |
290 | * @size: size | |
291 | * | |
292 | * Queue a series of bytes to the tty buffering. For each character | |
293 | * the flags array indicates the status of the character. Returns the | |
294 | * number added. | |
295 | * | |
ecbbfd44 | 296 | * Locking: Called functions may take port->buf.lock |
e0495736 AC |
297 | */ |
298 | ||
2f693357 | 299 | int tty_insert_flip_string_flags(struct tty_port *port, |
e0495736 AC |
300 | const unsigned char *chars, const char *flags, size_t size) |
301 | { | |
302 | int copied = 0; | |
303 | do { | |
d4bee0a6 | 304 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
64325a3b IZ |
305 | int space = tty_buffer_request_room(port, goal); |
306 | struct tty_buffer *tb = port->buf.tail; | |
e0495736 | 307 | /* If there is no space then tb may be NULL */ |
c56a00a1 | 308 | if (unlikely(space == 0)) { |
e0495736 | 309 | break; |
c56a00a1 | 310 | } |
1fc359fc PH |
311 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
312 | memcpy(flag_buf_ptr(tb, tb->used), flags, space); | |
e0495736 AC |
313 | tb->used += space; |
314 | copied += space; | |
315 | chars += space; | |
316 | flags += space; | |
317 | /* There is a small chance that we need to split the data over | |
318 | several buffers. If this is the case we must loop */ | |
319 | } while (unlikely(size > copied)); | |
320 | return copied; | |
321 | } | |
322 | EXPORT_SYMBOL(tty_insert_flip_string_flags); | |
323 | ||
324 | /** | |
325 | * tty_schedule_flip - push characters to ldisc | |
6732c8bb | 326 | * @port: tty port to push from |
e0495736 AC |
327 | * |
328 | * Takes any pending buffers and transfers their ownership to the | |
329 | * ldisc side of the queue. It then schedules those characters for | |
330 | * processing by the line discipline. | |
cee4ad1e IS |
331 | * Note that this function can only be used when the low_latency flag |
332 | * is unset. Otherwise the workqueue won't be flushed. | |
e0495736 | 333 | * |
ecbbfd44 | 334 | * Locking: Takes port->buf.lock |
e0495736 AC |
335 | */ |
336 | ||
6732c8bb | 337 | void tty_schedule_flip(struct tty_port *port) |
e0495736 | 338 | { |
6732c8bb | 339 | struct tty_bufhead *buf = &port->buf; |
e0495736 | 340 | unsigned long flags; |
6732c8bb | 341 | WARN_ON(port->low_latency); |
5cff39c6 JS |
342 | |
343 | spin_lock_irqsave(&buf->lock, flags); | |
344 | if (buf->tail != NULL) | |
345 | buf->tail->commit = buf->tail->used; | |
346 | spin_unlock_irqrestore(&buf->lock, flags); | |
347 | schedule_work(&buf->work); | |
e0495736 AC |
348 | } |
349 | EXPORT_SYMBOL(tty_schedule_flip); | |
350 | ||
351 | /** | |
352 | * tty_prepare_flip_string - make room for characters | |
2f693357 | 353 | * @port: tty port |
e0495736 AC |
354 | * @chars: return pointer for character write area |
355 | * @size: desired size | |
356 | * | |
357 | * Prepare a block of space in the buffer for data. Returns the length | |
358 | * available and buffer pointer to the space which is now allocated and | |
359 | * accounted for as ready for normal characters. This is used for drivers | |
360 | * that need their own block copy routines into the buffer. There is no | |
361 | * guarantee the buffer is a DMA target! | |
362 | * | |
ecbbfd44 | 363 | * Locking: May call functions taking port->buf.lock |
e0495736 AC |
364 | */ |
365 | ||
2f693357 | 366 | int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, |
ecbbfd44 | 367 | size_t size) |
e0495736 | 368 | { |
64325a3b | 369 | int space = tty_buffer_request_room(port, size); |
e0495736 | 370 | if (likely(space)) { |
64325a3b | 371 | struct tty_buffer *tb = port->buf.tail; |
1fc359fc PH |
372 | *chars = char_buf_ptr(tb, tb->used); |
373 | memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); | |
e0495736 AC |
374 | tb->used += space; |
375 | } | |
376 | return space; | |
377 | } | |
378 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
379 | ||
380 | /** | |
381 | * tty_prepare_flip_string_flags - make room for characters | |
2f693357 | 382 | * @port: tty port |
e0495736 AC |
383 | * @chars: return pointer for character write area |
384 | * @flags: return pointer for status flag write area | |
385 | * @size: desired size | |
386 | * | |
387 | * Prepare a block of space in the buffer for data. Returns the length | |
388 | * available and buffer pointer to the space which is now allocated and | |
389 | * accounted for as ready for characters. This is used for drivers | |
390 | * that need their own block copy routines into the buffer. There is no | |
391 | * guarantee the buffer is a DMA target! | |
392 | * | |
ecbbfd44 | 393 | * Locking: May call functions taking port->buf.lock |
e0495736 AC |
394 | */ |
395 | ||
2f693357 | 396 | int tty_prepare_flip_string_flags(struct tty_port *port, |
e0495736 AC |
397 | unsigned char **chars, char **flags, size_t size) |
398 | { | |
64325a3b | 399 | int space = tty_buffer_request_room(port, size); |
e0495736 | 400 | if (likely(space)) { |
64325a3b | 401 | struct tty_buffer *tb = port->buf.tail; |
1fc359fc PH |
402 | *chars = char_buf_ptr(tb, tb->used); |
403 | *flags = flag_buf_ptr(tb, tb->used); | |
e0495736 AC |
404 | tb->used += space; |
405 | } | |
406 | return space; | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
409 | ||
410 | ||
da261e7f PH |
411 | static int |
412 | receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count) | |
413 | { | |
414 | struct tty_ldisc *disc = tty->ldisc; | |
1fc359fc PH |
415 | unsigned char *p = char_buf_ptr(head, head->read); |
416 | char *f = flag_buf_ptr(head, head->read); | |
da261e7f | 417 | |
24a89d1c PH |
418 | if (disc->ops->receive_buf2) |
419 | count = disc->ops->receive_buf2(tty, p, f, count); | |
420 | else { | |
421 | count = min_t(int, count, tty->receive_room); | |
422 | if (count) | |
423 | disc->ops->receive_buf(tty, p, f, count); | |
424 | } | |
da261e7f PH |
425 | head->read += count; |
426 | return count; | |
427 | } | |
e0495736 AC |
428 | |
429 | /** | |
430 | * flush_to_ldisc | |
431 | * @work: tty structure passed from work queue. | |
432 | * | |
433 | * This routine is called out of the software interrupt to flush data | |
434 | * from the buffer chain to the line discipline. | |
435 | * | |
436 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
437 | * while invoking the line discipline receive_buf method. The | |
438 | * receive_buf method is single threaded for each tty instance. | |
439 | */ | |
440 | ||
441 | static void flush_to_ldisc(struct work_struct *work) | |
442 | { | |
ecbbfd44 JS |
443 | struct tty_port *port = container_of(work, struct tty_port, buf.work); |
444 | struct tty_bufhead *buf = &port->buf; | |
445 | struct tty_struct *tty; | |
e0495736 AC |
446 | unsigned long flags; |
447 | struct tty_ldisc *disc; | |
e0495736 | 448 | |
ecbbfd44 | 449 | tty = port->itty; |
34dcfb84 | 450 | if (tty == NULL) |
ecbbfd44 JS |
451 | return; |
452 | ||
e0495736 | 453 | disc = tty_ldisc_ref(tty); |
36697529 | 454 | if (disc == NULL) |
e0495736 AC |
455 | return; |
456 | ||
5cff39c6 | 457 | spin_lock_irqsave(&buf->lock, flags); |
45242006 | 458 | |
2fc20661 | 459 | if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) { |
81de916f | 460 | struct tty_buffer *head; |
5cff39c6 | 461 | while ((head = buf->head) != NULL) { |
45242006 | 462 | int count; |
45242006 LT |
463 | |
464 | count = head->commit - head->read; | |
e0495736 AC |
465 | if (!count) { |
466 | if (head->next == NULL) | |
467 | break; | |
5cff39c6 | 468 | buf->head = head->next; |
ecbbfd44 | 469 | tty_buffer_free(port, head); |
e0495736 AC |
470 | continue; |
471 | } | |
5cff39c6 | 472 | spin_unlock_irqrestore(&buf->lock, flags); |
da261e7f PH |
473 | |
474 | count = receive_buf(tty, head, count); | |
475 | ||
5cff39c6 | 476 | spin_lock_irqsave(&buf->lock, flags); |
39f610e4 PH |
477 | /* Ldisc or user is trying to flush the buffers. |
478 | We may have a deferred request to flush the | |
479 | input buffer, if so pull the chain under the lock | |
480 | and empty the queue */ | |
481 | if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) { | |
482 | __tty_buffer_flush(port); | |
483 | clear_bit(TTYP_FLUSHPENDING, &port->iflags); | |
484 | wake_up(&tty->read_wait); | |
485 | break; | |
da261e7f PH |
486 | } else if (!count) |
487 | break; | |
e0495736 | 488 | } |
2fc20661 | 489 | clear_bit(TTYP_FLUSHING, &port->iflags); |
e0495736 | 490 | } |
45242006 | 491 | |
5cff39c6 | 492 | spin_unlock_irqrestore(&buf->lock, flags); |
e0495736 AC |
493 | |
494 | tty_ldisc_deref(disc); | |
495 | } | |
496 | ||
e043e42b OH |
497 | /** |
498 | * tty_flush_to_ldisc | |
499 | * @tty: tty to push | |
500 | * | |
501 | * Push the terminal flip buffers to the line discipline. | |
502 | * | |
503 | * Must not be called from IRQ context. | |
504 | */ | |
505 | void tty_flush_to_ldisc(struct tty_struct *tty) | |
506 | { | |
d6c53c0e | 507 | if (!tty->port->low_latency) |
ecbbfd44 | 508 | flush_work(&tty->port->buf.work); |
e043e42b OH |
509 | } |
510 | ||
e0495736 AC |
511 | /** |
512 | * tty_flip_buffer_push - terminal | |
2e124b4a | 513 | * @port: tty port to push |
e0495736 AC |
514 | * |
515 | * Queue a push of the terminal flip buffers to the line discipline. This | |
d6c53c0e JS |
516 | * function must not be called from IRQ context if port->low_latency is |
517 | * set. | |
e0495736 AC |
518 | * |
519 | * In the event of the queue being busy for flipping the work will be | |
520 | * held off and retried later. | |
521 | * | |
522 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
523 | */ | |
524 | ||
2e124b4a | 525 | void tty_flip_buffer_push(struct tty_port *port) |
e0495736 | 526 | { |
2e124b4a | 527 | struct tty_bufhead *buf = &port->buf; |
e0495736 | 528 | unsigned long flags; |
5cff39c6 JS |
529 | |
530 | spin_lock_irqsave(&buf->lock, flags); | |
531 | if (buf->tail != NULL) | |
532 | buf->tail->commit = buf->tail->used; | |
533 | spin_unlock_irqrestore(&buf->lock, flags); | |
e0495736 | 534 | |
2e124b4a | 535 | if (port->low_latency) |
5cff39c6 | 536 | flush_to_ldisc(&buf->work); |
e0495736 | 537 | else |
5cff39c6 | 538 | schedule_work(&buf->work); |
e0495736 AC |
539 | } |
540 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
541 | ||
542 | /** | |
543 | * tty_buffer_init - prepare a tty buffer structure | |
544 | * @tty: tty to initialise | |
545 | * | |
546 | * Set up the initial state of the buffer management for a tty device. | |
547 | * Must be called before the other tty buffer functions are used. | |
548 | * | |
549 | * Locking: none | |
550 | */ | |
551 | ||
ecbbfd44 | 552 | void tty_buffer_init(struct tty_port *port) |
e0495736 | 553 | { |
ecbbfd44 | 554 | struct tty_bufhead *buf = &port->buf; |
5cff39c6 JS |
555 | |
556 | spin_lock_init(&buf->lock); | |
557 | buf->head = NULL; | |
558 | buf->tail = NULL; | |
559 | buf->free = NULL; | |
560 | buf->memory_used = 0; | |
561 | INIT_WORK(&buf->work, flush_to_ldisc); | |
e0495736 AC |
562 | } |
563 |