tools lib bpf: Add flags to bpf_create_map()

Commit 6c905981743 ("bpf: pre-allocate hash map elements") introduces
map_flags to bpf_attr for BPF_MAP_CREATE command. Expose this new
parameter in libbpf.

By exposing it, users can access flags such as whether or not to
preallocate the map.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: http://lkml.kernel.org/r/20161209024620.31660-4-joe@ovn.org
[ Added clarifying comment made by Wang Nan ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 89e8e8e..d0afb26 100644 (file)
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -54,7 +54,7 @@ static int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
 }
 
 int bpf_create_map(enum bpf_map_type map_type, int key_size,
-                  int value_size, int max_entries)
+                  int value_size, int max_entries, __u32 map_flags)
 {
        union bpf_attr attr;
 
@@ -64,6 +64,7 @@ int bpf_create_map(enum bpf_map_type map_type, int key_size,
        attr.key_size = key_size;
        attr.value_size = value_size;
        attr.max_entries = max_entries;
+       attr.map_flags = map_flags;
 
        return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
 }

diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 6113017..7fcdce1 100644 (file)
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -24,7 +24,7 @@
 #include <linux/bpf.h>
 
 int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,
-                  int max_entries);
+                  int max_entries, __u32 map_flags);
 
 /* Recommend log buffer size */
 #define BPF_LOG_BUF_SIZE 65536

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2e97459..84e6b35 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -854,7 +854,8 @@ bpf_object__create_maps(struct bpf_object *obj)
                *pfd = bpf_create_map(def->type,
                                      def->key_size,
                                      def->value_size,
-                                     def->max_entries);
+                                     def->max_entries,
+                                     0);
                if (*pfd < 0) {
                        size_t j;
                        int err = *pfd;