Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753275AbbFAKB0 (ORCPT <rfc822;w@1wt.eu>);
	Mon, 1 Jun 2015 06:01:26 -0400
Received: from lhrrgout.huawei.com ([194.213.3.17]:11516 "EHLO
	lhrrgout.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752558AbbFAJzN (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 1 Jun 2015 05:55:13 -0400
From: Wang Nan <wangnan0@huawei.com>
To: <namhyung@kernel.org>, <alexei.starovoitov@gmail.com>,
        <masami.hiramatsu.pt@hitachi.com>, <acme@kernel.org>,
        <paulus@samba.org>, <a.p.zijlstra@chello.nl>, <mingo@redhat.com>,
        <jolsa@kernel.org>, <dsahern@gmail.com>, <daniel@iogearbox.net>,
        <brendan.d.gregg@gmail.com>
CC: <lizefan@huawei.com>, <hekuang@huawei.com>, <xiakaixu@huawei.com>,
        <linux-kernel@vger.kernel.org>, <pi3orama@163.com>
Subject: [RFC PATCH v5 22/30] bpf tools: Link all bpf objects onto a list
Date: Mon, 1 Jun 2015 07:38:08 +0000
Message-ID: <1433144296-74992-23-git-send-email-wangnan0@huawei.com>
X-Mailer: git-send-email 1.8.3.4
In-Reply-To: <1433144296-74992-1-git-send-email-wangnan0@huawei.com>
References: <1433144296-74992-1-git-send-email-wangnan0@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
X-Originating-IP: [10.107.197.200]
X-CFilter-Loop: Reflected
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 3254
Lines: 117

To prevent caller from creating additional structures to hold
pointers of 'struct bpf_object', this patch link all such
structures onto a list (hidden to user). bpf_object__for_each() is
introduced to allow users iterate over each objects.
bpf_object__for_each() is safe even user close the object during
iteration.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 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 8ff6b05..1497d6b 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;
@@ -135,6 +138,12 @@ 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.fd >= 0)
@@ -240,6 +249,9 @@ static struct bpf_object *bpf_object__new(const char *path)
 	strcpy(obj->path, path);
 	obj->efile.fd = -1;
 	obj->loaded = false;
+
+	INIT_LIST_HEAD(&obj->list);
+	list_add(&obj->list, &bpf_objects_list);
 	return obj;
 }
 
@@ -877,6 +889,7 @@ void bpf_object__close(struct bpf_object *obj)
 	}
 	zfree(&obj->programs);
 
+	list_del(&obj->list);
 	free(obj);
 }
 
@@ -889,6 +902,25 @@ int bpf_object__get_prog_cnt(struct bpf_object *obj, size_t *pcnt)
 	return 0;
 }
 
+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 6b144f9..ff1f211 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -36,6 +36,13 @@ int bpf_object__unload(struct bpf_object *obj);
 /* Accessors of bpf_object */
 int bpf_object__get_prog_cnt(struct bpf_object *obj, size_t *pcnt);
 
+struct bpf_object *bpf_object__next(struct bpf_object *prev);
+#define bpf_object__for_each(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,
-- 
1.8.3.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/