[PATCH bpf-next] bpf: add support for other map types to bpf_map_lookup_and_delete_elem

[Luka Oreskovic]

Since this function already exists, it made sense to implement it for
map types other than stack and queue. This patch adds the necessary parts
from bpf_map_lookup_elem and bpf_map_delete_elem so it works as expected
for all map types.

Signed-off-by: Luka Oreskovic <luka.oresko...@sartura.hr>
CC: Juraj Vijtiuk <juraj.vijt...@sartura.hr>
CC: Luka Perkov <luka.per...@sartura.hr>
---
 kernel/bpf/syscall.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 2ce32cad5c8e..955de6ca8c45 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1475,6 +1475,9 @@ static int map_lookup_and_delete_elem(union bpf_attr 
*attr)
        if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM))
                return -EINVAL;
 
+       if (attr->flags & ~BPF_F_LOCK)
+               return -EINVAL;
+
        f = fdget(ufd);
        map = __bpf_map_get(f);
        if (IS_ERR(map))
@@ -1485,13 +1488,19 @@ static int map_lookup_and_delete_elem(union bpf_attr 
*attr)
                goto err_put;
        }
 
+       if ((attr->flags & BPF_F_LOCK) &&
+           !map_value_has_spin_lock(map)) {
+               err = -EINVAL;
+               goto err_put;
+       }
+
        key = __bpf_copy_key(ukey, map->key_size);
        if (IS_ERR(key)) {
                err = PTR_ERR(key);
                goto err_put;
        }
 
-       value_size = map->value_size;
+       value_size = bpf_map_value_size(map);
 
        err = -ENOMEM;
        value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
@@ -1502,7 +1511,24 @@ static int map_lookup_and_delete_elem(union bpf_attr 
*attr)
            map->map_type == BPF_MAP_TYPE_STACK) {
                err = map->ops->map_pop_elem(map, value);
        } else {
-               err = -ENOTSUPP;
+               err = bpf_map_copy_value(map, key, value, attr->flags);
+               if (err)
+                       goto free_value;
+
+               if (bpf_map_is_dev_bound(map)) {
+                       err = bpf_map_offload_delete_elem(map, key);
+               } else if (IS_FD_PROG_ARRAY(map) ||
+                          map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+                       /* These maps require sleepable context */
+                       err = map->ops->map_delete_elem(map, key);
+               } else {
+                       bpf_disable_instrumentation();
+                       rcu_read_lock();
+                       err = map->ops->map_delete_elem(map, key);
+                       rcu_read_unlock();
+                       bpf_enable_instrumentation();
+                       maybe_wait_bpf_programs(map);
+               }
        }
 
        if (err)
-- 
2.26.2