xref: /dpdk/lib/reorder/rte_reorder.c (revision f4eac3a09c51a1a2dab1f2fd3a10fe0619286a0d)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #include <inttypes.h>
6 #include <string.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 
65 	if (b == NULL) {
66 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer parameter:"
67 					" NULL\n");
68 		rte_errno = EINVAL;
69 		return NULL;
70 	}
71 	if (!rte_is_power_of_2(size)) {
72 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer size"
73 				" - Not a power of 2\n");
74 		rte_errno = EINVAL;
75 		return NULL;
76 	}
77 	if (name == NULL) {
78 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer name ptr:"
79 					" NULL\n");
80 		rte_errno = EINVAL;
81 		return NULL;
82 	}
83 	if (bufsize < min_bufsize) {
84 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer memory size: %u, "
85 			"minimum required: %u\n", bufsize, min_bufsize);
86 		rte_errno = EINVAL;
87 		return NULL;
88 	}
89 
90 	memset(b, 0, bufsize);
91 	strlcpy(b->name, name, sizeof(b->name));
92 	b->memsize = bufsize;
93 	b->order_buf.size = b->ready_buf.size = size;
94 	b->order_buf.mask = b->ready_buf.mask = size - 1;
95 	b->ready_buf.entries = (void *)&b[1];
96 	b->order_buf.entries = RTE_PTR_ADD(&b[1],
97 			size * sizeof(b->ready_buf.entries[0]));
98 
99 	return b;
100 }
101 
102 struct rte_reorder_buffer*
103 rte_reorder_create(const char *name, unsigned socket_id, unsigned int size)
104 {
105 	struct rte_reorder_buffer *b = NULL;
106 	struct rte_tailq_entry *te;
107 	struct rte_reorder_list *reorder_list;
108 	const unsigned int bufsize = sizeof(struct rte_reorder_buffer) +
109 					(2 * size * sizeof(struct rte_mbuf *));
110 	static const struct rte_mbuf_dynfield reorder_seqn_dynfield_desc = {
111 		.name = RTE_REORDER_SEQN_DYNFIELD_NAME,
112 		.size = sizeof(rte_reorder_seqn_t),
113 		.align = __alignof__(rte_reorder_seqn_t),
114 	};
115 
116 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
117 
118 	/* Check user arguments. */
119 	if (!rte_is_power_of_2(size)) {
120 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer size"
121 				" - Not a power of 2\n");
122 		rte_errno = EINVAL;
123 		return NULL;
124 	}
125 	if (name == NULL) {
126 		RTE_LOG(ERR, REORDER, "Invalid reorder buffer name ptr:"
127 					" NULL\n");
128 		rte_errno = EINVAL;
129 		return NULL;
130 	}
131 
132 	rte_reorder_seqn_dynfield_offset =
133 		rte_mbuf_dynfield_register(&reorder_seqn_dynfield_desc);
134 	if (rte_reorder_seqn_dynfield_offset < 0) {
135 		RTE_LOG(ERR, REORDER, "Failed to register mbuf field for reorder sequence number\n");
136 		rte_errno = ENOMEM;
137 		return NULL;
138 	}
139 
140 	rte_mcfg_tailq_write_lock();
141 
142 	/* guarantee there's no existing */
143 	TAILQ_FOREACH(te, reorder_list, next) {
144 		b = (struct rte_reorder_buffer *) te->data;
145 		if (strncmp(name, b->name, RTE_REORDER_NAMESIZE) == 0)
146 			break;
147 	}
148 	if (te != NULL)
149 		goto exit;
150 
151 	/* allocate tailq entry */
152 	te = rte_zmalloc("REORDER_TAILQ_ENTRY", sizeof(*te), 0);
153 	if (te == NULL) {
154 		RTE_LOG(ERR, REORDER, "Failed to allocate tailq entry\n");
155 		rte_errno = ENOMEM;
156 		b = NULL;
157 		goto exit;
158 	}
159 
160 	/* Allocate memory to store the reorder buffer structure. */
161 	b = rte_zmalloc_socket("REORDER_BUFFER", bufsize, 0, socket_id);
162 	if (b == NULL) {
163 		RTE_LOG(ERR, REORDER, "Memzone allocation failed\n");
164 		rte_errno = ENOMEM;
165 		rte_free(te);
166 	} else {
167 		rte_reorder_init(b, bufsize, name, size);
168 		te->data = (void *)b;
169 		TAILQ_INSERT_TAIL(reorder_list, te, next);
170 	}
171 
172 exit:
173 	rte_mcfg_tailq_write_unlock();
174 	return b;
175 }
176 
177 void
178 rte_reorder_reset(struct rte_reorder_buffer *b)
179 {
180 	char name[RTE_REORDER_NAMESIZE];
181 
182 	rte_reorder_free_mbufs(b);
183 	strlcpy(name, b->name, sizeof(name));
184 	/* No error checking as current values should be valid */
185 	rte_reorder_init(b, b->memsize, name, b->order_buf.size);
186 }
187 
188 static void
189 rte_reorder_free_mbufs(struct rte_reorder_buffer *b)
190 {
191 	unsigned i;
192 
193 	/* Free up the mbufs of order buffer & ready buffer */
194 	for (i = 0; i < b->order_buf.size; i++) {
195 		rte_pktmbuf_free(b->order_buf.entries[i]);
196 		rte_pktmbuf_free(b->ready_buf.entries[i]);
197 	}
198 }
199 
200 void
201 rte_reorder_free(struct rte_reorder_buffer *b)
202 {
203 	struct rte_reorder_list *reorder_list;
204 	struct rte_tailq_entry *te;
205 
206 	/* Check user arguments. */
207 	if (b == NULL)
208 		return;
209 
210 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
211 
212 	rte_mcfg_tailq_write_lock();
213 
214 	/* find our tailq entry */
215 	TAILQ_FOREACH(te, reorder_list, next) {
216 		if (te->data == (void *) b)
217 			break;
218 	}
219 	if (te == NULL) {
220 		rte_mcfg_tailq_write_unlock();
221 		return;
222 	}
223 
224 	TAILQ_REMOVE(reorder_list, te, next);
225 
226 	rte_mcfg_tailq_write_unlock();
227 
228 	rte_reorder_free_mbufs(b);
229 
230 	rte_free(b);
231 	rte_free(te);
232 }
233 
234 struct rte_reorder_buffer *
235 rte_reorder_find_existing(const char *name)
236 {
237 	struct rte_reorder_buffer *b = NULL;
238 	struct rte_tailq_entry *te;
239 	struct rte_reorder_list *reorder_list;
240 
241 	if (name == NULL) {
242 		rte_errno = EINVAL;
243 		return NULL;
244 	}
245 
246 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
247 
248 	rte_mcfg_tailq_read_lock();
249 	TAILQ_FOREACH(te, reorder_list, next) {
250 		b = (struct rte_reorder_buffer *) te->data;
251 		if (strncmp(name, b->name, RTE_REORDER_NAMESIZE) == 0)
252 			break;
253 	}
254 	rte_mcfg_tailq_read_unlock();
255 
256 	if (te == NULL) {
257 		rte_errno = ENOENT;
258 		return NULL;
259 	}
260 
261 	return b;
262 }
263 
264 static unsigned
265 rte_reorder_fill_overflow(struct rte_reorder_buffer *b, unsigned n)
266 {
267 	/*
268 	 * 1. Move all ready entries that fit to the ready_buf
269 	 * 2. check if we meet the minimum needed (n).
270 	 * 3. If not, then skip any gaps and keep moving.
271 	 * 4. If at any point the ready buffer is full, stop
272 	 * 5. Return the number of positions the order_buf head has moved
273 	 */
274 
275 	struct cir_buffer *order_buf = &b->order_buf,
276 			*ready_buf = &b->ready_buf;
277 
278 	unsigned int order_head_adv = 0;
279 
280 	/*
281 	 * move at least n packets to ready buffer, assuming ready buffer
282 	 * has room for those packets.
283 	 */
284 	while (order_head_adv < n &&
285 			((ready_buf->head + 1) & ready_buf->mask) != ready_buf->tail) {
286 
287 		/* if we are blocked waiting on a packet, skip it */
288 		if (order_buf->entries[order_buf->head] == NULL) {
289 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
290 			order_head_adv++;
291 		}
292 
293 		/* Move all ready entries that fit to the ready_buf */
294 		while (order_buf->entries[order_buf->head] != NULL) {
295 			ready_buf->entries[ready_buf->head] =
296 					order_buf->entries[order_buf->head];
297 
298 			order_buf->entries[order_buf->head] = NULL;
299 			order_head_adv++;
300 
301 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
302 
303 			if (((ready_buf->head + 1) & ready_buf->mask) == ready_buf->tail)
304 				break;
305 
306 			ready_buf->head = (ready_buf->head + 1) & ready_buf->mask;
307 		}
308 	}
309 
310 	b->min_seqn += order_head_adv;
311 	/* Return the number of positions the order_buf head has moved */
312 	return order_head_adv;
313 }
314 
315 int
316 rte_reorder_insert(struct rte_reorder_buffer *b, struct rte_mbuf *mbuf)
317 {
318 	uint32_t offset, position;
319 	struct cir_buffer *order_buf;
320 
321 	if (b == NULL || mbuf == NULL) {
322 		rte_errno = EINVAL;
323 		return -1;
324 	}
325 
326 	order_buf = &b->order_buf;
327 	if (!b->is_initialized) {
328 		b->min_seqn = *rte_reorder_seqn(mbuf);
329 		b->is_initialized = 1;
330 	}
331 
332 	/*
333 	 * calculate the offset from the head pointer we need to go.
334 	 * The subtraction takes care of the sequence number wrapping.
335 	 * For example (using 16-bit for brevity):
336 	 *	min_seqn  = 0xFFFD
337 	 *	mbuf_seqn = 0x0010
338 	 *	offset    = 0x0010 - 0xFFFD = 0x13
339 	 */
340 	offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
341 
342 	/*
343 	 * action to take depends on offset.
344 	 * offset < buffer->size: the mbuf fits within the current window of
345 	 *    sequence numbers we can reorder. EXPECTED CASE.
346 	 * offset > buffer->size: the mbuf is outside the current window. There
347 	 *    are a number of cases to consider:
348 	 *    1. The packet sequence is just outside the window, then we need
349 	 *       to see about shifting the head pointer and taking any ready
350 	 *       to return packets out of the ring. If there was a delayed
351 	 *       or dropped packet preventing drains from shifting the window
352 	 *       this case will skip over the dropped packet instead, and any
353 	 *       packets dequeued here will be returned on the next drain call.
354 	 *    2. The packet sequence number is vastly outside our window, taken
355 	 *       here as having offset greater than twice the buffer size. In
356 	 *       this case, the packet is probably an old or late packet that
357 	 *       was previously skipped, so just enqueue the packet for
358 	 *       immediate return on the next drain call, or else return error.
359 	 */
360 	if (offset < b->order_buf.size) {
361 		position = (order_buf->head + offset) & order_buf->mask;
362 		order_buf->entries[position] = mbuf;
363 	} else if (offset < 2 * b->order_buf.size) {
364 		if (rte_reorder_fill_overflow(b, offset + 1 - order_buf->size)
365 				< (offset + 1 - order_buf->size)) {
366 			/* Put in handling for enqueue straight to output */
367 			rte_errno = ENOSPC;
368 			return -1;
369 		}
370 		offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
371 		position = (order_buf->head + offset) & order_buf->mask;
372 		order_buf->entries[position] = mbuf;
373 	} else {
374 		/* Put in handling for enqueue straight to output */
375 		rte_errno = ERANGE;
376 		return -1;
377 	}
378 	return 0;
379 }
380 
381 unsigned int
382 rte_reorder_drain(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
383 		unsigned max_mbufs)
384 {
385 	unsigned int drain_cnt = 0;
386 
387 	struct cir_buffer *order_buf = &b->order_buf,
388 			*ready_buf = &b->ready_buf;
389 
390 	/* Try to fetch requested number of mbufs from ready buffer */
391 	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
392 		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
393 		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
394 	}
395 
396 	/*
397 	 * If requested number of buffers not fetched from ready buffer, fetch
398 	 * remaining buffers from order buffer
399 	 */
400 	while ((drain_cnt < max_mbufs) &&
401 			(order_buf->entries[order_buf->head] != NULL)) {
402 		mbufs[drain_cnt++] = order_buf->entries[order_buf->head];
403 		order_buf->entries[order_buf->head] = NULL;
404 		b->min_seqn++;
405 		order_buf->head = (order_buf->head + 1) & order_buf->mask;
406 	}
407 
408 	return drain_cnt;
409 }
410