[PATCH bpf-next 2/8] bpf: inline map creation logic in map_create() function

[Andrii Nakryiko <andrii@xxxxxxxxxx>]

Keep all the relevant generic sanity checks, permission checks, and
creation and initialization logic in one linear piece of code. Currently
helper function that handles memory allocation and partial
initialization is split apart and is about 1000 lines higher in the
file, hurting readability.

Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
 kernel/bpf/syscall.c | 54 ++++++++++++++++++--------------------------
 1 file changed, 22 insertions(+), 32 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c1d268025985..a090737f98ea 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -108,37 +108,6 @@ const struct bpf_map_ops bpf_map_offload_ops = {
 	.map_mem_usage = bpf_map_offload_map_mem_usage,
 };
 
-static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
-{
-	const struct bpf_map_ops *ops;
-	u32 type = attr->map_type;
-	struct bpf_map *map;
-	int err;
-
-	if (type >= ARRAY_SIZE(bpf_map_types))
-		return ERR_PTR(-EINVAL);
-	type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
-	ops = bpf_map_types[type];
-	if (!ops)
-		return ERR_PTR(-EINVAL);
-
-	if (ops->map_alloc_check) {
-		err = ops->map_alloc_check(attr);
-		if (err)
-			return ERR_PTR(err);
-	}
-	if (attr->map_ifindex)
-		ops = &bpf_map_offload_ops;
-	if (!ops->map_mem_usage)
-		return ERR_PTR(-EINVAL);
-	map = ops->map_alloc(attr);
-	if (IS_ERR(map))
-		return map;
-	map->ops = ops;
-	map->map_type = type;
-	return map;
-}
-
 static void bpf_map_write_active_inc(struct bpf_map *map)
 {
 	atomic64_inc(&map->writecnt);
@@ -1124,7 +1093,9 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
 /* called via syscall */
 static int map_create(union bpf_attr *attr)
 {
+	const struct bpf_map_ops *ops;
 	int numa_node = bpf_map_attr_numa_node(attr);
+	u32 map_type = attr->map_type;
 	struct btf_field_offs *foffs;
 	struct bpf_map *map;
 	int f_flags;
@@ -1167,9 +1138,28 @@ static int map_create(union bpf_attr *attr)
 		return -EINVAL;
 
 	/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
-	map = find_and_alloc_map(attr);
+	map_type = attr->map_type;
+	if (map_type >= ARRAY_SIZE(bpf_map_types))
+		return -EINVAL;
+	map_type = array_index_nospec(map_type, ARRAY_SIZE(bpf_map_types));
+	ops = bpf_map_types[map_type];
+	if (!ops)
+		return -EINVAL;
+
+	if (ops->map_alloc_check) {
+		err = ops->map_alloc_check(attr);
+		if (err)
+			return err;
+	}
+	if (attr->map_ifindex)
+		ops = &bpf_map_offload_ops;
+	if (!ops->map_mem_usage)
+		return -EINVAL;
+	map = ops->map_alloc(attr);
 	if (IS_ERR(map))
 		return PTR_ERR(map);
+	map->ops = ops;
+	map->map_type = map_type;
 
 	err = bpf_obj_name_cpy(map->name, attr->map_name,
 			       sizeof(attr->map_name));
-- 
2.34.1