by tip-bot for Vasyl Gomonovych

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Subject: [tip:perf/core] bpf tools: Link all bpf objects onto a list

Commit-ID: 9a208effd1832e50e1f7ea002f400f8b9ca8b1ed
Gitweb: http://git.kernel.org/tip/9a208effd1832e50e1f7ea002f400f8b9ca8b1ed
Author: Wang Nan <[email protected]>
AuthorDate: Wed, 1 Jul 2015 02:14:10 +0000
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Fri, 7 Aug 2015 10:16:59 -0300

bpf tools: Link all bpf objects onto a list

To allow enumeration of all bpf_objects, keep them in a list (hidden to
caller). bpf_object__for_each_safe() is introduced to do this iteration.
It is safe even user close the object during iteration.

Signed-off-by: Wang Nan <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/lib/bpf/libbpf.c | 32 ++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 7 +++++++
2 files changed, 39 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ae1c5cb..4fa4bc4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -17,6 +17,7 @@
#include <asm/unistd.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
+#include <linux/list.h>
#include <libelf.h>
#include <gelf.h>

@@ -104,6 +105,8 @@ struct bpf_program {
bpf_program_clear_priv_t clear_priv;
};

+static LIST_HEAD(bpf_objects_list);
+
struct bpf_object {
char license[64];
u32 kern_version;
@@ -137,6 +140,12 @@ struct bpf_object {
} *reloc;
int nr_reloc;
} efile;
+ /*
+ * All loaded bpf_object is linked in a list, which is
+ * hidden to caller. bpf_objects__<func> handlers deal with
+ * all objects.
+ */
+ struct list_head list;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
@@ -265,6 +274,9 @@ static struct bpf_object *bpf_object__new(const char *path,
obj->efile.obj_buf_sz = obj_buf_sz;

obj->loaded = false;
+
+ INIT_LIST_HEAD(&obj->list);
+ list_add(&obj->list, &bpf_objects_list);
return obj;
}

@@ -940,9 +952,29 @@ void bpf_object__close(struct bpf_object *obj)
}
zfree(&obj->programs);

+ list_del(&obj->list);
free(obj);
}

+struct bpf_object *
+bpf_object__next(struct bpf_object *prev)
+{
+ struct bpf_object *next;
+
+ if (!prev)
+ next = list_first_entry(&bpf_objects_list,
+ struct bpf_object,
+ list);
+ else
+ next = list_next_entry(prev, list);
+
+ /* Empty list is noticed here so don't need checking on entry. */
+ if (&next->list == &bpf_objects_list)
+ return NULL;
+
+ return next;
+}
+
struct bpf_program *
bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
{
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 657e497..ea8adc2 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -35,6 +35,13 @@ void bpf_object__close(struct bpf_object *object);
int bpf_object__load(struct bpf_object *obj);
int bpf_object__unload(struct bpf_object *obj);

+struct bpf_object *bpf_object__next(struct bpf_object *prev);
+#define bpf_object__for_each_safe(pos, tmp) \
+ for ((pos) = bpf_object__next(NULL), \
+ (tmp) = bpf_object__next(pos); \
+ (pos) != NULL; \
+ (pos) = (tmp), (tmp) = bpf_object__next(tmp))
+
/* Accessors of bpf_program. */
struct bpf_program;
struct bpf_program *bpf_program__next(struct bpf_program *prog,