netdev - [PATCH bpf-next v2 2/2] bpf: libbpf: move map name retry into libbpf.c

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Date:   Tue, 20 Nov 2018 15:15:10 -0800
From:   Stanislav Fomichev <sdf@...gle.com>
To:     netdev@...r.kernel.org, ast@...nel.org
Cc:     daniel@...earbox.net, Stanislav Fomichev <sdf@...gle.com>
Subject: [PATCH bpf-next v2 2/2] bpf: libbpf: move map name retry into libbpf.c

To be in line with the previous commit ("bpf: libbpf: retry program
creation without the name"), do the retry at the higher level, not the
syscall level.

Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
 tools/lib/bpf/bpf.c    | 11 +----------
 tools/lib/bpf/libbpf.c | 11 +++++++++++
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 836447bb4f14..ce1822194590 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -69,7 +69,6 @@ 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));
 
@@ -87,15 +86,7 @@ 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;
+	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
 }
 
 int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2ea14dfa28fc..c081b5b8f68f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1184,6 +1184,17 @@ bpf_object__create_maps(struct bpf_object *obj)
 			*pfd = bpf_create_map_xattr(&create_attr);
 		}
 
+		if (*pfd < 0 && errno == EINVAL && create_attr.name) {
+			/* Retry the same operation, but without the name.
+			 * Pre v4.14 kernels don't support map names.
+			 */
+			cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+			pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without name.\n",
+				   map->name, cp, errno);
+			create_attr.name = NULL;
+			*pfd = bpf_create_map_xattr(&create_attr);
+		}
+
 		if (*pfd < 0) {
 			size_t j;
 
-- 
2.19.1.1215.g8438c0b245-goog