xref: /f-stack/dpdk/lib/librte_ring/rte_ring.c (revision 16d80a6d)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  *
3  * Copyright (c) 2010-2015 Intel Corporation
4  * Copyright (c) 2007,2008 Kip Macy [email protected]
5  * All rights reserved.
6  * Derived from FreeBSD's bufring.h
7  * Used as BSD-3 Licensed with permission from Kip Macy.
8  */
9 
10 #include <stdio.h>
11 #include <stdarg.h>
12 #include <string.h>
13 #include <stdint.h>
14 #include <inttypes.h>
15 #include <errno.h>
16 #include <sys/queue.h>
17 
18 #include <rte_common.h>
19 #include <rte_log.h>
20 #include <rte_memory.h>
21 #include <rte_memzone.h>
22 #include <rte_malloc.h>
23 #include <rte_launch.h>
24 #include <rte_eal.h>
25 #include <rte_eal_memconfig.h>
26 #include <rte_atomic.h>
27 #include <rte_per_lcore.h>
28 #include <rte_lcore.h>
29 #include <rte_branch_prediction.h>
30 #include <rte_errno.h>
31 #include <rte_string_fns.h>
32 #include <rte_spinlock.h>
33 
34 #include "rte_ring.h"
35 
36 TAILQ_HEAD(rte_ring_list, rte_tailq_entry);
37 
38 static struct rte_tailq_elem rte_ring_tailq = {
39 	.name = RTE_TAILQ_RING_NAME,
40 };
41 EAL_REGISTER_TAILQ(rte_ring_tailq)
42 
43 /* true if x is a power of 2 */
44 #define POWEROF2(x) ((((x)-1) & (x)) == 0)
45 
46 /* return the size of memory occupied by a ring */
47 ssize_t
48 rte_ring_get_memsize(unsigned count)
49 {
50 	ssize_t sz;
51 
52 	/* count must be a power of 2 */
53 	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
54 		RTE_LOG(ERR, RING,
55 			"Requested size is invalid, must be power of 2, and "
56 			"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
57 		return -EINVAL;
58 	}
59 
60 	sz = sizeof(struct rte_ring) + count * sizeof(void *);
61 	sz = RTE_ALIGN(sz, RTE_CACHE_LINE_SIZE);
62 	return sz;
63 }
64 
65 int
66 rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
67 	unsigned flags)
68 {
69 	int ret;
70 
71 	/* compilation-time checks */
72 	RTE_BUILD_BUG_ON((sizeof(struct rte_ring) &
73 			  RTE_CACHE_LINE_MASK) != 0);
74 	RTE_BUILD_BUG_ON((offsetof(struct rte_ring, cons) &
75 			  RTE_CACHE_LINE_MASK) != 0);
76 	RTE_BUILD_BUG_ON((offsetof(struct rte_ring, prod) &
77 			  RTE_CACHE_LINE_MASK) != 0);
78 
79 	/* init the ring structure */
80 	memset(r, 0, sizeof(*r));
81 	ret = snprintf(r->name, sizeof(r->name), "%s", name);
82 	if (ret < 0 || ret >= (int)sizeof(r->name))
83 		return -ENAMETOOLONG;
84 	r->flags = flags;
85 	r->prod.single = (flags & RING_F_SP_ENQ) ? __IS_SP : __IS_MP;
86 	r->cons.single = (flags & RING_F_SC_DEQ) ? __IS_SC : __IS_MC;
87 
88 	if (flags & RING_F_EXACT_SZ) {
89 		r->size = rte_align32pow2(count + 1);
90 		r->mask = r->size - 1;
91 		r->capacity = count;
92 	} else {
93 		if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
94 			RTE_LOG(ERR, RING,
95 				"Requested size is invalid, must be power of 2, and not exceed the size limit %u\n",
96 				RTE_RING_SZ_MASK);
97 			return -EINVAL;
98 		}
99 		r->size = count;
100 		r->mask = count - 1;
101 		r->capacity = r->mask;
102 	}
103 	r->prod.head = r->cons.head = 0;
104 	r->prod.tail = r->cons.tail = 0;
105 
106 	return 0;
107 }
108 
109 /* create the ring */
110 struct rte_ring *
111 rte_ring_create(const char *name, unsigned count, int socket_id,
112 		unsigned flags)
113 {
114 	char mz_name[RTE_MEMZONE_NAMESIZE];
115 	struct rte_ring *r;
116 	struct rte_tailq_entry *te;
117 	const struct rte_memzone *mz;
118 	ssize_t ring_size;
119 	int mz_flags = 0;
120 	struct rte_ring_list* ring_list = NULL;
121 	const unsigned int requested_count = count;
122 	int ret;
123 
124 	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
125 
126 	/* for an exact size ring, round up from count to a power of two */
127 	if (flags & RING_F_EXACT_SZ)
128 		count = rte_align32pow2(count + 1);
129 
130 	ring_size = rte_ring_get_memsize(count);
131 	if (ring_size < 0) {
132 		rte_errno = ring_size;
133 		return NULL;
134 	}
135 
136 	ret = snprintf(mz_name, sizeof(mz_name), "%s%s",
137 		RTE_RING_MZ_PREFIX, name);
138 	if (ret < 0 || ret >= (int)sizeof(mz_name)) {
139 		rte_errno = ENAMETOOLONG;
140 		return NULL;
141 	}
142 
143 	te = rte_zmalloc("RING_TAILQ_ENTRY", sizeof(*te), 0);
144 	if (te == NULL) {
145 		RTE_LOG(ERR, RING, "Cannot reserve memory for tailq\n");
146 		rte_errno = ENOMEM;
147 		return NULL;
148 	}
149 
150 	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
151 
152 	/* reserve a memory zone for this ring. If we can't get rte_config or
153 	 * we are secondary process, the memzone_reserve function will set
154 	 * rte_errno for us appropriately - hence no check in this this function */
155 	mz = rte_memzone_reserve_aligned(mz_name, ring_size, socket_id,
156 					 mz_flags, __alignof__(*r));
157 	if (mz != NULL) {
158 		r = mz->addr;
159 		/* no need to check return value here, we already checked the
160 		 * arguments above */
161 		rte_ring_init(r, name, requested_count, flags);
162 
163 		te->data = (void *) r;
164 		r->memzone = mz;
165 
166 		TAILQ_INSERT_TAIL(ring_list, te, next);
167 	} else {
168 		r = NULL;
169 		RTE_LOG(ERR, RING, "Cannot reserve memory\n");
170 		rte_free(te);
171 	}
172 	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
173 
174 	return r;
175 }
176 
177 /* free the ring */
178 void
179 rte_ring_free(struct rte_ring *r)
180 {
181 	struct rte_ring_list *ring_list = NULL;
182 	struct rte_tailq_entry *te;
183 
184 	if (r == NULL)
185 		return;
186 
187 	/*
188 	 * Ring was not created with rte_ring_create,
189 	 * therefore, there is no memzone to free.
190 	 */
191 	if (r->memzone == NULL) {
192 		RTE_LOG(ERR, RING,
193 			"Cannot free ring, not created with rte_ring_create()\n");
194 		return;
195 	}
196 
197 	if (rte_memzone_free(r->memzone) != 0) {
198 		RTE_LOG(ERR, RING, "Cannot free memory\n");
199 		return;
200 	}
201 
202 	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
203 	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
204 
205 	/* find out tailq entry */
206 	TAILQ_FOREACH(te, ring_list, next) {
207 		if (te->data == (void *) r)
208 			break;
209 	}
210 
211 	if (te == NULL) {
212 		rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
213 		return;
214 	}
215 
216 	TAILQ_REMOVE(ring_list, te, next);
217 
218 	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
219 
220 	rte_free(te);
221 }
222 
223 /* dump the status of the ring on the console */
224 void
225 rte_ring_dump(FILE *f, const struct rte_ring *r)
226 {
227 	fprintf(f, "ring <%s>@%p\n", r->name, r);
228 	fprintf(f, "  flags=%x\n", r->flags);
229 	fprintf(f, "  size=%"PRIu32"\n", r->size);
230 	fprintf(f, "  capacity=%"PRIu32"\n", r->capacity);
231 	fprintf(f, "  ct=%"PRIu32"\n", r->cons.tail);
232 	fprintf(f, "  ch=%"PRIu32"\n", r->cons.head);
233 	fprintf(f, "  pt=%"PRIu32"\n", r->prod.tail);
234 	fprintf(f, "  ph=%"PRIu32"\n", r->prod.head);
235 	fprintf(f, "  used=%u\n", rte_ring_count(r));
236 	fprintf(f, "  avail=%u\n", rte_ring_free_count(r));
237 }
238 
239 /* dump the status of all rings on the console */
240 void
241 rte_ring_list_dump(FILE *f)
242 {
243 	const struct rte_tailq_entry *te;
244 	struct rte_ring_list *ring_list;
245 
246 	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
247 
248 	rte_rwlock_read_lock(RTE_EAL_TAILQ_RWLOCK);
249 
250 	TAILQ_FOREACH(te, ring_list, next) {
251 		rte_ring_dump(f, (struct rte_ring *) te->data);
252 	}
253 
254 	rte_rwlock_read_unlock(RTE_EAL_TAILQ_RWLOCK);
255 }
256 
257 /* search a ring from its name */
258 struct rte_ring *
259 rte_ring_lookup(const char *name)
260 {
261 	struct rte_tailq_entry *te;
262 	struct rte_ring *r = NULL;
263 	struct rte_ring_list *ring_list;
264 
265 	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
266 
267 	rte_rwlock_read_lock(RTE_EAL_TAILQ_RWLOCK);
268 
269 	TAILQ_FOREACH(te, ring_list, next) {
270 		r = (struct rte_ring *) te->data;
271 		if (strncmp(name, r->name, RTE_RING_NAMESIZE) == 0)
272 			break;
273 	}
274 
275 	rte_rwlock_read_unlock(RTE_EAL_TAILQ_RWLOCK);
276 
277 	if (te == NULL) {
278 		rte_errno = ENOENT;
279 		return NULL;
280 	}
281 
282 	return r;
283 }
284