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Commit f6d66139 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Greg Kroah-Hartman
Browse files

bpf: libbpf: retry map creation without the name 



[ Upstream commit 23499442c319412aa8e54e7a939e2eb531bdd77d ]

Since commit 88cda1c9 ("bpf: libbpf: Provide basic API support
to specify BPF obj name"), libbpf unconditionally sets bpf_attr->name
for maps. Pre v4.14 kernels don't know about map names and return an
error about unexpected non-zero data. Retry sys_bpf without a map
name to cover older kernels.

v2 changes:
* check for errno == EINVAL as suggested by Daniel Borkmann

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0857b843

tools/lib/bpf/bpf.c

+10 −1
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) 
{

	__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;

	union bpf_attr attr;

	int ret;



	memset(&attr, '\0', sizeof(attr));
@@ -94,8 +95,16 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) 
	attr.map_ifindex = create_attr->map_ifindex;

	attr.inner_map_fd = create_attr->inner_map_fd;



	ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));

	if (ret < 0 && errno == EINVAL && create_attr->name) {

		/* Retry the same syscall, but without the name.

		 * Pre v4.14 kernels don't support map names.

		 */

		memset(attr.map_name, 0, sizeof(attr.map_name));

		return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));

	}

	return ret;

}



int bpf_create_map_node(enum bpf_map_type map_type, const char *name,

			int key_size, int value_size, int max_entries,