3 files changed, 30 insertions, 4 deletions

diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
index f81e549ddfdb..4db74758c674 100644
--- a/tools/lib/bpf/.gitignore
+++ b/tools/lib/bpf/.gitignore
@@ -1,2 +1,3 @@
 libbpf_version.h
 FEATURE-DUMP.libbpf
+test_libbpf
diff --git a/tools/lib/bpf/README.rst b/tools/lib/bpf/README.rst
index 056f38310722..607aae40f4ed 100644
--- a/tools/lib/bpf/README.rst
+++ b/tools/lib/bpf/README.rst
@@ -132,6 +132,20 @@ For example, if current state of ``libbpf.map`` is:
 Format of version script and ways to handle ABI changes, including
 incompatible ones, described in details in [1].
 
+Stand-alone build
+=================
+
+Under https://github.com/libbpf/libbpf there is a (semi-)automated
+mirror of the mainline's version of libbpf for a stand-alone build.
+
+However, all changes to libbpf's code base must be upstreamed through
+the mainline kernel tree.
+
+License
+=======
+
+libbpf is dual-licensed under LGPL 2.1 and BSD 2-Clause.
+
 Links
 =====
 
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 3caaa3428774..88cbd110ae58 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -65,6 +65,17 @@ static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
         return syscall(__NR_bpf, cmd, attr, size);
 }
 
+static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size)
+{
+        int fd;
+
+        do {
+                fd = sys_bpf(BPF_PROG_LOAD, attr, size);
+        } while (fd < 0 && errno == EAGAIN);
+
+        return fd;
+}
+
 int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
 {
         __u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
@@ -232,7 +243,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
         memcpy(attr.prog_name, load_attr->name,
                min(name_len, BPF_OBJ_NAME_LEN - 1));
 
-        fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+        fd = sys_bpf_prog_load(&attr, sizeof(attr));
         if (fd >= 0)
                 return fd;
 
@@ -269,7 +280,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
                         break;
                 }
 
-                fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+                fd = sys_bpf_prog_load(&attr, sizeof(attr));
 
                 if (fd >= 0)
                         goto done;
@@ -283,7 +294,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
         attr.log_size = log_buf_sz;
         attr.log_level = 1;
         log_buf[0] = 0;
-        fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+        fd = sys_bpf_prog_load(&attr, sizeof(attr));
 done:
         free(finfo);
         free(linfo);
@@ -328,7 +339,7 @@ int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
         attr.kern_version = kern_version;
         attr.prog_flags = prog_flags;
 
-        return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+        return sys_bpf_prog_load(&attr, sizeof(attr));
 }
 
 int bpf_map_update_elem(int fd, const void *key, const void *value,