[5.10,v2,2/3] Revert "bpf: Eliminate rlimit-based memory accounting for devmap maps"

Commit Message

Pu Lehui Sept. 27, 2024, 1:51 p.m. UTC

From: Pu Lehui <[e-mail]>

This reverts commit 70294d8bc31f3b7789e5e32f757aa9344556d964.

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/[e-mail] [0]
Signed-off-by: Pu Lehui <[e-mail]>
---
 kernel/bpf/devmap.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

Patch

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index ca2cade2871b..01149821ded9 100644
--- 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)