xref: /dpdk/lib/reorder/rte_reorder.c (revision 2bf48044dca1892e571fd4964eecaacf6cb0c1c2)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #include <string.h>
6 #include <sys/queue.h>
7 
8 #include <rte_string_fns.h>
9 #include <rte_log.h>
10 #include <rte_mbuf.h>
11 #include <rte_mbuf_dyn.h>
12 #include <rte_eal_memconfig.h>
13 #include <rte_errno.h>
14 #include <rte_malloc.h>
15 #include <rte_tailq.h>
16 
17 #include "rte_reorder.h"
18 
19 TAILQ_HEAD(rte_reorder_list, rte_tailq_entry);
20 
21 static struct rte_tailq_elem rte_reorder_tailq = {
22 	.name = "RTE_REORDER",
23 };
24 EAL_REGISTER_TAILQ(rte_reorder_tailq)
25 
26 #define NO_FLAGS 0
27 #define RTE_REORDER_PREFIX "RO_"
28 #define RTE_REORDER_NAMESIZE 32
29 
30 /* Macros for printing using RTE_LOG */
31 #define RTE_LOGTYPE_REORDER	RTE_LOGTYPE_USER1
32 
33 #define RTE_REORDER_SEQN_DYNFIELD_NAME "rte_reorder_seqn_dynfield"
34 int rte_reorder_seqn_dynfield_offset = -1;
35 
36 /* A generic circular buffer */
37 struct cir_buffer {
38 	unsigned int size;   /**< Number of entries that can be stored */
39 	unsigned int mask;   /**< [buffer_size - 1]: used for wrap-around */
40 	unsigned int head;   /**< insertion point in buffer */
41 	unsigned int tail;   /**< extraction point in buffer */
42 	struct rte_mbuf **entries;
43 } __rte_cache_aligned;
44 
45 /* The reorder buffer data structure itself */
46 struct rte_reorder_buffer {
47 	char name[RTE_REORDER_NAMESIZE];
48 	uint32_t min_seqn;  /**< Lowest seq. number that can be in the buffer */
49 	unsigned int memsize; /**< memory area size of reorder buffer */
50 	struct cir_buffer ready_buf; /**< temp buffer for dequeued entries */
51 	struct cir_buffer order_buf; /**< buffer used to reorder entries */
52 	int is_initialized;
53 } __rte_cache_aligned;
54 
55 static void
56 rte_reorder_free_mbufs(struct rte_reorder_buffer *b);
57 
58 struct rte_reorder_buffer *
59 rte_reorder_init(struct rte_reorder_buffer *b, unsigned int bufsize,
60 		const char *name, unsigned int size)
61 {
62 	const unsigned int min_bufsize = sizeof(*b) +
63 					(2 * size * sizeof(struct rte_mbuf *));
64 	static const struct rte_mbuf_dynfield reorder_seqn_dynfield_desc = {
65 		.name = RTE_REORDER_SEQN_DYNFIELD_NAME,
66 		.size = sizeof(rte_reorder_seqn_t),
67 		.align = __alignof__(rte_reorder_seqn_t),
68 	};
69 
70 	if (b == NULL) {
71 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer parameter:"
72 					" NULL\n");
73 		rte_errno = EINVAL;
74 		return NULL;
75 	}
76 	if (!rte_is_power_of_2(size)) {
77 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer size"
78 				" - Not a power of 2\n");
79 		rte_errno = EINVAL;
80 		return NULL;
81 	}
82 	if (name == NULL) {
83 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer name ptr:"
84 					" NULL\n");
85 		rte_errno = EINVAL;
86 		return NULL;
87 	}
88 	if (bufsize < min_bufsize) {
89 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer memory size: %u, "
90 			"minimum required: %u\n", bufsize, min_bufsize);
91 		rte_errno = EINVAL;
92 		return NULL;
93 	}
94 
95 	rte_reorder_seqn_dynfield_offset = rte_mbuf_dynfield_register(&reorder_seqn_dynfield_desc);
96 	if (rte_reorder_seqn_dynfield_offset < 0) {
97 		RTE_LOG(ERR, REORDER,
98 			"Failed to register mbuf field for reorder sequence number, rte_errno: %i\n",
99 			rte_errno);
100 		rte_errno = ENOMEM;
101 		return NULL;
102 	}
103 
104 	memset(b, 0, bufsize);
105 	strlcpy(b->name, name, sizeof(b->name));
106 	b->memsize = bufsize;
107 	b->order_buf.size = b->ready_buf.size = size;
108 	b->order_buf.mask = b->ready_buf.mask = size - 1;
109 	b->ready_buf.entries = (void *)&b[1];
110 	b->order_buf.entries = RTE_PTR_ADD(&b[1],
111 			size * sizeof(b->ready_buf.entries[0]));
112 
113 	return b;
114 }
115 
116 /*
117  * Insert new entry into global list.
118  * Returns pointer to already inserted entry if such exists, or to newly inserted one.
119  */
120 static struct rte_tailq_entry *
121 rte_reorder_entry_insert(struct rte_tailq_entry *new_te)
122 {
123 	struct rte_reorder_list *reorder_list;
124 	struct rte_reorder_buffer *b, *nb;
125 	struct rte_tailq_entry *te;
126 
127 	rte_mcfg_tailq_write_lock();
128 
129 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
130 	/* guarantee there's no existing */
131 	TAILQ_FOREACH(te, reorder_list, next) {
132 		b = (struct rte_reorder_buffer *) te->data;
133 		nb = (struct rte_reorder_buffer *) new_te->data;
134 		if (strncmp(nb->name, b->name, RTE_REORDER_NAMESIZE) == 0)
135 			break;
136 	}
137 
138 	if (te == NULL) {
139 		TAILQ_INSERT_TAIL(reorder_list, new_te, next);
140 		te = new_te;
141 	}
142 
143 	rte_mcfg_tailq_write_unlock();
144 
145 	return te;
146 }
147 
148 struct rte_reorder_buffer*
149 rte_reorder_create(const char *name, unsigned socket_id, unsigned int size)
150 {
151 	struct rte_reorder_buffer *b = NULL;
152 	struct rte_tailq_entry *te, *te_inserted;
153 	const unsigned int bufsize = sizeof(struct rte_reorder_buffer) +
154 					(2 * size * sizeof(struct rte_mbuf *));
155 
156 	/* Check user arguments. */
157 	if (!rte_is_power_of_2(size)) {
158 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer size"
159 				" - Not a power of 2\n");
160 		rte_errno = EINVAL;
161 		return NULL;
162 	}
163 	if (name == NULL) {
164 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer name ptr:"
165 					" NULL\n");
166 		rte_errno = EINVAL;
167 		return NULL;
168 	}
169 
170 	/* allocate tailq entry */
171 	te = rte_zmalloc("REORDER_TAILQ_ENTRY", sizeof(*te), 0);
172 	if (te == NULL) {
173 		RTE_LOG(ERR, REORDER, "Failed to allocate tailq entry\n");
174 		rte_errno = ENOMEM;
175 		return NULL;
176 	}
177 
178 	/* Allocate memory to store the reorder buffer structure. */
179 	b = rte_zmalloc_socket("REORDER_BUFFER", bufsize, 0, socket_id);
180 	if (b == NULL) {
181 		RTE_LOG(ERR, REORDER, "Memzone allocation failed\n");
182 		rte_errno = ENOMEM;
183 		rte_free(te);
184 		return NULL;
185 	} else {
186 		if (rte_reorder_init(b, bufsize, name, size) == NULL) {
187 			rte_free(b);
188 			rte_free(te);
189 			return NULL;
190 		}
191 		te->data = (void *)b;
192 	}
193 
194 	te_inserted = rte_reorder_entry_insert(te);
195 	if (te_inserted != te) {
196 		rte_free(b);
197 		rte_free(te);
198 		return te_inserted->data;
199 	}
200 
201 	return b;
202 }
203 
204 void
205 rte_reorder_reset(struct rte_reorder_buffer *b)
206 {
207 	char name[RTE_REORDER_NAMESIZE];
208 
209 	rte_reorder_free_mbufs(b);
210 	strlcpy(name, b->name, sizeof(name));
211 	/* No error checking as current values should be valid */
212 	rte_reorder_init(b, b->memsize, name, b->order_buf.size);
213 }
214 
215 static void
216 rte_reorder_free_mbufs(struct rte_reorder_buffer *b)
217 {
218 	unsigned i;
219 
220 	/* Free up the mbufs of order buffer & ready buffer */
221 	for (i = 0; i < b->order_buf.size; i++) {
222 		rte_pktmbuf_free(b->order_buf.entries[i]);
223 		rte_pktmbuf_free(b->ready_buf.entries[i]);
224 	}
225 }
226 
227 void
228 rte_reorder_free(struct rte_reorder_buffer *b)
229 {
230 	struct rte_reorder_list *reorder_list;
231 	struct rte_tailq_entry *te;
232 
233 	/* Check user arguments. */
234 	if (b == NULL)
235 		return;
236 
237 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
238 
239 	rte_mcfg_tailq_write_lock();
240 
241 	/* find our tailq entry */
242 	TAILQ_FOREACH(te, reorder_list, next) {
243 		if (te->data == (void *) b)
244 			break;
245 	}
246 	if (te == NULL) {
247 		rte_mcfg_tailq_write_unlock();
248 		return;
249 	}
250 
251 	TAILQ_REMOVE(reorder_list, te, next);
252 
253 	rte_mcfg_tailq_write_unlock();
254 
255 	rte_reorder_free_mbufs(b);
256 
257 	rte_free(b);
258 	rte_free(te);
259 }
260 
261 struct rte_reorder_buffer *
262 rte_reorder_find_existing(const char *name)
263 {
264 	struct rte_reorder_buffer *b = NULL;
265 	struct rte_tailq_entry *te;
266 	struct rte_reorder_list *reorder_list;
267 
268 	if (name == NULL) {
269 		rte_errno = EINVAL;
270 		return NULL;
271 	}
272 
273 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
274 
275 	rte_mcfg_tailq_read_lock();
276 	TAILQ_FOREACH(te, reorder_list, next) {
277 		b = (struct rte_reorder_buffer *) te->data;
278 		if (strncmp(name, b->name, RTE_REORDER_NAMESIZE) == 0)
279 			break;
280 	}
281 	rte_mcfg_tailq_read_unlock();
282 
283 	if (te == NULL) {
284 		rte_errno = ENOENT;
285 		return NULL;
286 	}
287 
288 	return b;
289 }
290 
291 static unsigned
292 rte_reorder_fill_overflow(struct rte_reorder_buffer *b, unsigned n)
293 {
294 	/*
295 	 * 1. Move all ready entries that fit to the ready_buf
296 	 * 2. check if we meet the minimum needed (n).
297 	 * 3. If not, then skip any gaps and keep moving.
298 	 * 4. If at any point the ready buffer is full, stop
299 	 * 5. Return the number of positions the order_buf head has moved
300 	 */
301 
302 	struct cir_buffer *order_buf = &b->order_buf,
303 			*ready_buf = &b->ready_buf;
304 
305 	unsigned int order_head_adv = 0;
306 
307 	/*
308 	 * move at least n packets to ready buffer, assuming ready buffer
309 	 * has room for those packets.
310 	 */
311 	while (order_head_adv < n &&
312 			((ready_buf->head + 1) & ready_buf->mask) != ready_buf->tail) {
313 
314 		/* if we are blocked waiting on a packet, skip it */
315 		if (order_buf->entries[order_buf->head] == NULL) {
316 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
317 			order_head_adv++;
318 		}
319 
320 		/* Move all ready entries that fit to the ready_buf */
321 		while (order_buf->entries[order_buf->head] != NULL) {
322 			ready_buf->entries[ready_buf->head] =
323 					order_buf->entries[order_buf->head];
324 
325 			order_buf->entries[order_buf->head] = NULL;
326 			order_head_adv++;
327 
328 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
329 
330 			if (((ready_buf->head + 1) & ready_buf->mask) == ready_buf->tail)
331 				break;
332 
333 			ready_buf->head = (ready_buf->head + 1) & ready_buf->mask;
334 		}
335 	}
336 
337 	b->min_seqn += order_head_adv;
338 	/* Return the number of positions the order_buf head has moved */
339 	return order_head_adv;
340 }
341 
342 int
343 rte_reorder_insert(struct rte_reorder_buffer *b, struct rte_mbuf *mbuf)
344 {
345 	uint32_t offset, position;
346 	struct cir_buffer *order_buf;
347 
348 	if (b == NULL || mbuf == NULL) {
349 		rte_errno = EINVAL;
350 		return -1;
351 	}
352 
353 	order_buf = &b->order_buf;
354 	if (!b->is_initialized) {
355 		b->min_seqn = *rte_reorder_seqn(mbuf);
356 		b->is_initialized = 1;
357 	}
358 
359 	/*
360 	 * calculate the offset from the head pointer we need to go.
361 	 * The subtraction takes care of the sequence number wrapping.
362 	 * For example (using 16-bit for brevity):
363 	 *	min_seqn  = 0xFFFD
364 	 *	mbuf_seqn = 0x0010
365 	 *	offset    = 0x0010 - 0xFFFD = 0x13
366 	 */
367 	offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
368 
369 	/*
370 	 * action to take depends on offset.
371 	 * offset < buffer->size: the mbuf fits within the current window of
372 	 *    sequence numbers we can reorder. EXPECTED CASE.
373 	 * offset > buffer->size: the mbuf is outside the current window. There
374 	 *    are a number of cases to consider:
375 	 *    1. The packet sequence is just outside the window, then we need
376 	 *       to see about shifting the head pointer and taking any ready
377 	 *       to return packets out of the ring. If there was a delayed
378 	 *       or dropped packet preventing drains from shifting the window
379 	 *       this case will skip over the dropped packet instead, and any
380 	 *       packets dequeued here will be returned on the next drain call.
381 	 *    2. The packet sequence number is vastly outside our window, taken
382 	 *       here as having offset greater than twice the buffer size. In
383 	 *       this case, the packet is probably an old or late packet that
384 	 *       was previously skipped, so just enqueue the packet for
385 	 *       immediate return on the next drain call, or else return error.
386 	 */
387 	if (offset < b->order_buf.size) {
388 		position = (order_buf->head + offset) & order_buf->mask;
389 		order_buf->entries[position] = mbuf;
390 	} else if (offset < 2 * b->order_buf.size) {
391 		if (rte_reorder_fill_overflow(b, offset + 1 - order_buf->size)
392 				< (offset + 1 - order_buf->size)) {
393 			/* Put in handling for enqueue straight to output */
394 			rte_errno = ENOSPC;
395 			return -1;
396 		}
397 		offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
398 		position = (order_buf->head + offset) & order_buf->mask;
399 		order_buf->entries[position] = mbuf;
400 	} else {
401 		/* Put in handling for enqueue straight to output */
402 		rte_errno = ERANGE;
403 		return -1;
404 	}
405 	return 0;
406 }
407 
408 unsigned int
409 rte_reorder_drain(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
410 		unsigned max_mbufs)
411 {
412 	unsigned int drain_cnt = 0;
413 
414 	struct cir_buffer *order_buf = &b->order_buf,
415 			*ready_buf = &b->ready_buf;
416 
417 	/* Try to fetch requested number of mbufs from ready buffer */
418 	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
419 		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
420 		ready_buf->entries[ready_buf->tail] = NULL;
421 		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
422 	}
423 
424 	/*
425 	 * If requested number of buffers not fetched from ready buffer, fetch
426 	 * remaining buffers from order buffer
427 	 */
428 	while ((drain_cnt < max_mbufs) &&
429 			(order_buf->entries[order_buf->head] != NULL)) {
430 		mbufs[drain_cnt++] = order_buf->entries[order_buf->head];
431 		order_buf->entries[order_buf->head] = NULL;
432 		b->min_seqn++;
433 		order_buf->head = (order_buf->head + 1) & order_buf->mask;
434 	}
435 
436 	return drain_cnt;
437 }
438 
439 /* Binary search seqn in ready buffer */
440 static inline uint32_t
441 ready_buffer_seqn_find(const struct cir_buffer *ready_buf, const uint32_t seqn)
442 {
443 	uint32_t mid, value, position, high;
444 	uint32_t low = 0;
445 
446 	if (ready_buf->tail > ready_buf->head)
447 		high = ready_buf->tail - ready_buf->head;
448 	else
449 		high = ready_buf->head - ready_buf->tail;
450 
451 	while (low <= high) {
452 		mid = low + (high - low) / 2;
453 		position = (ready_buf->tail + mid) & ready_buf->mask;
454 		value = *rte_reorder_seqn(ready_buf->entries[position]);
455 		if (seqn == value)
456 			return mid;
457 		else if (seqn > value)
458 			low = mid + 1;
459 		else
460 			high = mid - 1;
461 	}
462 
463 	return low;
464 }
465 
466 unsigned int
467 rte_reorder_drain_up_to_seqn(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
468 		const unsigned int max_mbufs, const rte_reorder_seqn_t seqn)
469 {
470 	uint32_t i, position, offset;
471 	unsigned int drain_cnt = 0;
472 
473 	struct cir_buffer *order_buf = &b->order_buf,
474 			*ready_buf = &b->ready_buf;
475 
476 	/* Seqn in Ready buffer */
477 	if (seqn < b->min_seqn) {
478 		/* All sequence numbers are higher then given */
479 		if ((ready_buf->tail == ready_buf->head) ||
480 		    (*rte_reorder_seqn(ready_buf->entries[ready_buf->tail]) > seqn))
481 			return 0;
482 
483 		offset = ready_buffer_seqn_find(ready_buf, seqn);
484 
485 		for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
486 			position = (ready_buf->tail + i) & ready_buf->mask;
487 			mbufs[drain_cnt++] = ready_buf->entries[position];
488 			ready_buf->entries[position] = NULL;
489 		}
490 		ready_buf->tail = (ready_buf->tail + i) & ready_buf->mask;
491 
492 		return drain_cnt;
493 	}
494 
495 	/* Seqn in Order buffer, add all buffers from Ready buffer */
496 	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
497 		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
498 		ready_buf->entries[ready_buf->tail] = NULL;
499 		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
500 	}
501 
502 	/* Fetch buffers from Order buffer up to given sequence number (exclusive) */
503 	offset = RTE_MIN(seqn - b->min_seqn, b->order_buf.size);
504 	for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
505 		position = (order_buf->head + i) & order_buf->mask;
506 		if (order_buf->entries[position] == NULL)
507 			continue;
508 		mbufs[drain_cnt++] = order_buf->entries[position];
509 		order_buf->entries[position] = NULL;
510 	}
511 	b->min_seqn += i;
512 	order_buf->head = (order_buf->head + i) & order_buf->mask;
513 
514 	return drain_cnt;
515 }
516 
517 static bool
518 rte_reorder_is_empty(const struct rte_reorder_buffer *b)
519 {
520 	const struct cir_buffer *order_buf = &b->order_buf, *ready_buf = &b->ready_buf;
521 	unsigned int i;
522 
523 	/* Ready buffer does not have gaps */
524 	if (ready_buf->tail != ready_buf->head)
525 		return false;
526 
527 	/* Order buffer could have gaps, iterate */
528 	for (i = 0; i < order_buf->size; i++) {
529 		if (order_buf->entries[i] != NULL)
530 			return false;
531 	}
532 
533 	return true;
534 }
535 
536 unsigned int
537 rte_reorder_min_seqn_set(struct rte_reorder_buffer *b, rte_reorder_seqn_t min_seqn)
538 {
539 	if (!rte_reorder_is_empty(b))
540 		return -ENOTEMPTY;
541 
542 	b->min_seqn = min_seqn;
543 	b->is_initialized = true;
544 
545 	return 0;
546 }
547