Revert "bpf: Eliminate rlimit-based memory accounting for devmap maps"

This reverts commit 70294d8bc31f3b7789e5e32f757aa9344556d964 which is
commit 844f157f6c0a905d039d2e20212ab3231f2e5eaf upstream.

Commit 70294d8bc31f ("bpf: Eliminate rlimit-based memory accounting for
devmap maps") is part of the v5.11+ base mechanism of memcg-based memory
accounting[0]. The commit cannot be independently backported to the 5.10
stable branch, otherwise the related memory when creating devmap will be
unrestricted. Let's roll back to rlimit-based memory accounting mode for
devmap.

Link: https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@fb.com
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name revert-bpf-eliminate-rlimit-based-memory-accounting-for-devmap-maps.patch

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index ca2cade2871b868690f71b5a84c7d529094a48d7..01149821ded91a2995b58a6656edb6f05916102e 100644 (file)
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -109,6 +109,8 @@ static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
 static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
 {
        u32 valsize = attr->value_size;
+       u64 cost = 0;
+       int err;
 
        /* check sanity of attributes. 2 value sizes supported:
         * 4 bytes: ifindex
@@ -133,13 +135,21 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
 
                if (!dtab->n_buckets) /* Overflow check */
                        return -EINVAL;
+               cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;
+       } else {
+               cost += (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
        }
 
+       /* if map size is larger than memlock limit, reject it */
+       err = bpf_map_charge_init(&dtab->map.memory, cost);
+       if (err)
+               return -EINVAL;
+
        if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
                dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
                                                           dtab->map.numa_node);
                if (!dtab->dev_index_head)
-                       return -ENOMEM;
+                       goto free_charge;
 
                spin_lock_init(&dtab->index_lock);
        } else {
@@ -147,10 +157,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
                                                      sizeof(struct bpf_dtab_netdev *),
                                                      dtab->map.numa_node);
                if (!dtab->netdev_map)
-                       return -ENOMEM;
+                       goto free_charge;
        }
 
        return 0;
+
+free_charge:
+       bpf_map_charge_finish(&dtab->map.memory);
+       return -ENOMEM;
 }
 
 static struct bpf_map *dev_map_alloc(union bpf_attr *attr)