Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

[linux-2.6-microblaze.git] / kernel / bpf / bpf_struct_ops.c

diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index d9a3c92..84b2d9d 100644 (file)
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -341,6 +341,9 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
 
        tlinks[BPF_TRAMP_FENTRY].links[0] = link;
        tlinks[BPF_TRAMP_FENTRY].nr_links = 1;
+       /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
+        * and it must be used alone.
+        */
        flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
        return arch_prepare_bpf_trampoline(NULL, image, image_end,
                                           model, flags, tlinks, NULL);
@@ -503,10 +506,9 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
                goto unlock;
        }
 
-       /* Error during st_ops->reg().  It is very unlikely since
-        * the above init_member() should have caught it earlier
-        * before reg().  The only possibility is if there was a race
-        * in registering the struct_ops (under the same name) to
+       /* Error during st_ops->reg(). Can happen if this struct_ops needs to be
+        * verified as a whole, after all init_member() calls. Can also happen if
+        * there was a race in registering the struct_ops (under the same name) to
         * a sub-system through different struct_ops's maps.
         */
        set_memory_nx((long)st_map->image, 1);