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8020ceb5 MD |
1 | /* |
2 | * ltt-context.c | |
3 | * | |
4 | * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * LTTng trace/channel/event context management. | |
7 | * | |
8 | * Dual LGPL v2.1/GPL v2 license. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/list.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/slab.h> | |
15 | #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ | |
16 | #include "ltt-events.h" | |
17 | #include "ltt-tracer.h" | |
18 | ||
a0a748b8 MD |
19 | /* |
20 | * Note: as we append context information, the pointer location may change. | |
21 | */ | |
8020ceb5 MD |
22 | struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p) |
23 | { | |
24 | struct lttng_ctx_field *field; | |
25 | struct lttng_ctx *ctx; | |
26 | ||
27 | if (!*ctx_p) { | |
28 | *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL); | |
29 | if (!*ctx_p) | |
30 | return NULL; | |
31 | } | |
32 | ctx = *ctx_p; | |
33 | if (ctx->nr_fields + 1 > ctx->allocated_fields) { | |
34 | struct lttng_ctx_field *new_fields; | |
35 | ||
36 | ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields); | |
37 | new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL); | |
38 | if (!new_fields) | |
39 | return NULL; | |
40 | if (ctx->fields) | |
41 | memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields); | |
42 | kfree(ctx->fields); | |
43 | ctx->fields = new_fields; | |
44 | } | |
45 | field = &ctx->fields[ctx->nr_fields]; | |
46 | ctx->nr_fields++; | |
47 | return field; | |
48 | } | |
49 | EXPORT_SYMBOL_GPL(lttng_append_context); | |
50 | ||
b13d13b1 MD |
51 | /* |
52 | * Remove last context field. | |
53 | */ | |
8020ceb5 MD |
54 | void lttng_remove_context_field(struct lttng_ctx **ctx_p, |
55 | struct lttng_ctx_field *field) | |
56 | { | |
57 | struct lttng_ctx *ctx; | |
58 | ||
59 | ctx = *ctx_p; | |
60 | ctx->nr_fields--; | |
b13d13b1 | 61 | WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field); |
8020ceb5 MD |
62 | memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field)); |
63 | } | |
64 | EXPORT_SYMBOL_GPL(lttng_remove_context_field); | |
65 | ||
66 | void lttng_destroy_context(struct lttng_ctx *ctx) | |
67 | { | |
68 | int i; | |
69 | ||
70 | if (!ctx) | |
71 | return; | |
72 | for (i = 0; i < ctx->nr_fields; i++) { | |
73 | if (ctx->fields[i].destroy) | |
74 | ctx->fields[i].destroy(&ctx->fields[i]); | |
75 | } | |
76 | kfree(ctx->fields); | |
77 | kfree(ctx); | |
78 | } |