1 files changed, 33 insertions, 36 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8289a2ce14fc..4a5ebad99154 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -188,19 +188,6 @@ void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
         map->numa_node = bpf_map_attr_numa_node(attr);
 }
 
-int bpf_map_precharge_memlock(u32 pages)
-{
-        struct user_struct *user = get_current_user();
-        unsigned long memlock_limit, cur;
-
-        memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-        cur = atomic_long_read(&user->locked_vm);
-        free_uid(user);
-        if (cur + pages > memlock_limit)
-                return -EPERM;
-        return 0;
-}
-
 static int bpf_charge_memlock(struct user_struct *user, u32 pages)
 {
         unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
@@ -214,29 +201,40 @@ static int bpf_charge_memlock(struct user_struct *user, u32 pages)
 
 static void bpf_uncharge_memlock(struct user_struct *user, u32 pages)
 {
-        atomic_long_sub(pages, &user->locked_vm);
+        if (user)
+                atomic_long_sub(pages, &user->locked_vm);
 }
 
-static int bpf_map_init_memlock(struct bpf_map *map)
+int bpf_map_charge_init(struct bpf_map_memory *mem, u32 pages)
 {
         struct user_struct *user = get_current_user();
         int ret;
 
-        ret = bpf_charge_memlock(user, map->memory.pages);
+        ret = bpf_charge_memlock(user, pages);
         if (ret) {
                 free_uid(user);
                 return ret;
         }
-        map->memory.user = user;
-        return ret;
+
+        mem->pages = pages;
+        mem->user = user;
+
+        return 0;
 }
 
-static void bpf_map_release_memlock(struct bpf_map *map)
+void bpf_map_charge_finish(struct bpf_map_memory *mem)
 {
-        struct user_struct *user = map->memory.user;
+        bpf_uncharge_memlock(mem->user, mem->pages);
+        free_uid(mem->user);
+}
 
-        bpf_uncharge_memlock(user, map->memory.pages);
-        free_uid(user);
+void bpf_map_charge_move(struct bpf_map_memory *dst,
+                         struct bpf_map_memory *src)
+{
+        *dst = *src;
+
+        /* Make sure src will not be used for the redundant uncharging. */
+        memset(src, 0, sizeof(struct bpf_map_memory));
 }
 
 int bpf_map_charge_memlock(struct bpf_map *map, u32 pages)
@@ -304,11 +302,13 @@ void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock)
 static void bpf_map_free_deferred(struct work_struct *work)
 {
         struct bpf_map *map = container_of(work, struct bpf_map, work);
+        struct bpf_map_memory mem;
 
-        bpf_map_release_memlock(map);
+        bpf_map_charge_move(&mem, &map->memory);
         security_bpf_map_free(map);
         /* implementation dependent freeing */
         map->ops->map_free(map);
+        bpf_map_charge_finish(&mem);
 }
 
 static void bpf_map_put_uref(struct bpf_map *map)
@@ -550,6 +550,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
 static int map_create(union bpf_attr *attr)
 {
         int numa_node = bpf_map_attr_numa_node(attr);
+        struct bpf_map_memory mem;
         struct bpf_map *map;
         int f_flags;
         int err;
@@ -574,7 +575,7 @@ static int map_create(union bpf_attr *attr)
 
         err = bpf_obj_name_cpy(map->name, attr->map_name);
         if (err)
-                goto free_map_nouncharge;
+                goto free_map;
 
         atomic_set(&map->refcnt, 1);
         atomic_set(&map->usercnt, 1);
@@ -584,20 +585,20 @@ static int map_create(union bpf_attr *attr)
 
                 if (!attr->btf_value_type_id) {
                         err = -EINVAL;
-                        goto free_map_nouncharge;
+                        goto free_map;
                 }
 
                 btf = btf_get_by_fd(attr->btf_fd);
                 if (IS_ERR(btf)) {
                         err = PTR_ERR(btf);
-                        goto free_map_nouncharge;
+                        goto free_map;
                 }
 
                 err = map_check_btf(map, btf, attr->btf_key_type_id,
                                     attr->btf_value_type_id);
                 if (err) {
                         btf_put(btf);
-                        goto free_map_nouncharge;
+                        goto free_map;
                 }
 
                 map->btf = btf;
@@ -609,15 +610,11 @@ static int map_create(union bpf_attr *attr)
 
         err = security_bpf_map_alloc(map);
         if (err)
-                goto free_map_nouncharge;
-
-        err = bpf_map_init_memlock(map);
-        if (err)
-                goto free_map_sec;
+                goto free_map;
 
         err = bpf_map_alloc_id(map);
         if (err)
-                goto free_map;
+                goto free_map_sec;
 
         err = bpf_map_new_fd(map, f_flags);
         if (err < 0) {
@@ -633,13 +630,13 @@ static int map_create(union bpf_attr *attr)
 
         return err;
 
-free_map:
-        bpf_map_release_memlock(map);
 free_map_sec:
         security_bpf_map_free(map);
-free_map_nouncharge:
+free_map:
         btf_put(map->btf);
+        bpf_map_charge_move(&mem, &map->memory);
         map->ops->map_free(map);
+        bpf_map_charge_finish(&mem);
         return err;
 }