summaryrefslogtreecommitdiff
path: root/lib/librte_eal/common/include/rte_tailq.h
blob: 8dccaefc5534aa6a8ec1b8b33ac29659d8fbda19 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#ifndef _RTE_TAILQ_H_
#define _RTE_TAILQ_H_

/**
 * @file
 *  Here defines rte_tailq APIs for only internal use
 *
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <sys/queue.h>
#include <stdio.h>
#include <rte_debug.h>

/** dummy structure type used by the rte_tailq APIs */
struct rte_tailq_entry {
	TAILQ_ENTRY(rte_tailq_entry) next; /**< Pointer entries for a tailq list */
	void *data; /**< Pointer to the data referenced by this tailq entry */
};
/** dummy */
TAILQ_HEAD(rte_tailq_entry_head, rte_tailq_entry);

#define RTE_TAILQ_NAMESIZE 32

/**
 * The structure defining a tailq header entry for storing
 * in the rte_config structure in shared memory. Each tailq
 * is identified by name.
 * Any library storing a set of objects e.g. rings, mempools, hash-tables,
 * is recommended to use an entry here, so as to make it easy for
 * a multi-process app to find already-created elements in shared memory.
 */
struct rte_tailq_head {
	struct rte_tailq_entry_head tailq_head; /**< NOTE: must be first element */
	char name[RTE_TAILQ_NAMESIZE];
};

struct rte_tailq_elem {
	/**
	 * Reference to head in shared mem, updated at init time by
	 * rte_eal_tailqs_init()
	 */
	struct rte_tailq_head *head;
	TAILQ_ENTRY(rte_tailq_elem) next;
	const char name[RTE_TAILQ_NAMESIZE];
};

/**
 * Return the first tailq entry casted to the right struct.
 */
#define RTE_TAILQ_CAST(tailq_entry, struct_name) \
	(struct struct_name *)&(tailq_entry)->tailq_head

/**
 * Utility macro to make looking up a tailqueue for a particular struct easier.
 *
 * @param name
 *   The name of tailq
 *
 * @param struct_name
 *   The name of the list type we are using. (Generally this is the same as the
 *   first parameter passed to TAILQ_HEAD macro)
 *
 * @return
 *   The return value from rte_eal_tailq_lookup, typecast to the appropriate
 *   structure pointer type.
 *   NULL on error, since the tailq_head is the first
 *   element in the rte_tailq_head structure.
 */
#define RTE_TAILQ_LOOKUP(name, struct_name) \
	RTE_TAILQ_CAST(rte_eal_tailq_lookup(name), struct_name)

/**
 * Dump tail queues to a file.
 *
 * @param f
 *   A pointer to a file for output
 */
void rte_dump_tailq(FILE *f);

/**
 * Lookup for a tail queue.
 *
 * Get a pointer to a tail queue header of a tail
 * queue identified by the name given as an argument.
 * Note: this function is not multi-thread safe, and should only be called from
 * a single thread at a time
 *
 * @param name
 *   The name of the queue.
 * @return
 *   A pointer to the tail queue head structure.
 */
struct rte_tailq_head *rte_eal_tailq_lookup(const char *name);

/**
 * Register a tail queue.
 *
 * Register a tail queue from shared memory.
 * This function is mainly used by EAL_REGISTER_TAILQ macro which is used to
 * register tailq from the different dpdk libraries. Since this macro is a
 * constructor, the function has no access to dpdk shared memory, so the
 * registered tailq can not be used before call to rte_eal_init() which calls
 * rte_eal_tailqs_init().
 *
 * @param t
 *   The tailq element which contains the name of the tailq you want to
 *   create (/retrieve when in secondary process).
 * @return
 *   0 on success or -1 in case of an error.
 */
int rte_eal_tailq_register(struct rte_tailq_elem *t);

#define EAL_REGISTER_TAILQ(t) \
RTE_INIT(tailqinitfn_ ##t); \
static void tailqinitfn_ ##t(void) \
{ \
	if (rte_eal_tailq_register(&t) < 0) \
		rte_panic("Cannot initialize tailq: %s\n", t.name); \
}

/* This macro permits both remove and free var within the loop safely.*/
#ifndef TAILQ_FOREACH_SAFE
#define TAILQ_FOREACH_SAFE(var, head, field, tvar)		\
	for ((var) = TAILQ_FIRST((head));			\
	    (var) && ((tvar) = TAILQ_NEXT((var), field), 1);	\
	    (var) = (tvar))
#endif

#ifdef __cplusplus
}
#endif

#endif /* _RTE_TAILQ_H_ */