Revert "bpf: Add map and need_defer parameters to .map_fd_put_ptr()"

This reverts commit eb6f68ec92 which is
commit 20c20bd11a0702ce4dc9300c3da58acf551d9725 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I4611eed3677738ab29469733e2b4f6734ef3d605
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

include/linux/bpf.h

@@ -49,11 +49,7 @@ struct bpf_map_ops {
 	/* funcs called by prog_array and perf_event_array map */
 	void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file,
 				int fd);
-	/* If need_defer is true, the implementation should guarantee that
-	 * the to-be-put element is still alive before the bpf program, which
-	 * may manipulate it, exists.
-	 */
-	void (*map_fd_put_ptr)(struct bpf_map *map, void *ptr, bool need_defer);
+	void (*map_fd_put_ptr)(void *ptr);
 	u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
 	u32 (*map_fd_sys_lookup_elem)(void *ptr);
 	void (*map_seq_show_elem)(struct bpf_map *map, void *key,

kernel/bpf/arraymap.c

@@ -542,7 +542,7 @@ int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
 
 	old_ptr = xchg(array->ptrs + index, new_ptr);
 	if (old_ptr)
-		map->ops->map_fd_put_ptr(map, old_ptr, true);
+		map->ops->map_fd_put_ptr(old_ptr);
 
 	return 0;
 }
@@ -558,7 +558,7 @@ static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
 
 	old_ptr = xchg(array->ptrs + index, NULL);
 	if (old_ptr) {
-		map->ops->map_fd_put_ptr(map, old_ptr, true);
+		map->ops->map_fd_put_ptr(old_ptr);
 		return 0;
 	} else {
 		return -ENOENT;
@@ -582,9 +582,8 @@ static void *prog_fd_array_get_ptr(struct bpf_map *map,
 	return prog;
 }
 
-static void prog_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+static void prog_fd_array_put_ptr(void *ptr)
 {
-	/* bpf_prog is freed after one RCU or tasks trace grace period */
 	bpf_prog_put(ptr);
 }
 
@@ -695,9 +694,8 @@ err_out:
 	return ee;
 }
 
-static void perf_event_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+static void perf_event_fd_array_put_ptr(void *ptr)
 {
-	/* bpf_perf_event is freed after one RCU grace period */
 	bpf_event_entry_free_rcu(ptr);
 }
 
@@ -738,7 +736,7 @@ static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
 	return cgroup_get_from_fd(fd);
 }
 
-static void cgroup_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+static void cgroup_fd_array_put_ptr(void *ptr)
 {
 	/* cgroup_put free cgrp after a rcu grace period */
 	cgroup_put(ptr);

kernel/bpf/hashtab.c

@@ -674,7 +674,7 @@ static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
 
 	if (map->ops->map_fd_put_ptr) {
 		ptr = fd_htab_map_get_ptr(map, l);
-		map->ops->map_fd_put_ptr(map, ptr, true);
+		map->ops->map_fd_put_ptr(ptr);
 	}
 }
 
@@ -1426,7 +1426,7 @@ static void fd_htab_map_free(struct bpf_map *map)
 		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
 			void *ptr = fd_htab_map_get_ptr(map, l);
 
-			map->ops->map_fd_put_ptr(map, ptr, false);
+			map->ops->map_fd_put_ptr(ptr);
 		}
 	}
 
@@ -1467,7 +1467,7 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
 
 	ret = htab_map_update_elem(map, key, &ptr, map_flags);
 	if (ret)
-		map->ops->map_fd_put_ptr(map, ptr, false);
+		map->ops->map_fd_put_ptr(ptr);
 
 	return ret;
 }

kernel/bpf/map_in_map.c

@@ -106,7 +106,7 @@ void *bpf_map_fd_get_ptr(struct bpf_map *map,
 	return inner_map;
 }
 
-void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+void bpf_map_fd_put_ptr(void *ptr)
 {
 	/* ptr->ops->map_free() has to go through one
 	 * rcu grace period by itself.

kernel/bpf/map_in_map.h

@@ -15,7 +15,7 @@ bool bpf_map_meta_equal(const struct bpf_map *meta0,
 			const struct bpf_map *meta1);
 void *bpf_map_fd_get_ptr(struct bpf_map *map, struct file *map_file,
 			 int ufd);
-void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer);
+void bpf_map_fd_put_ptr(void *ptr);
 u32 bpf_map_fd_sys_lookup_elem(void *ptr);
 
 #endif