[PATCH net-next] bpf: return errno -ENOMEM when exceeding RLIMIT_MEMLOCK

[Jesper Dangaard Brouer]

It is confusing users of samples/bpf that exceeding the resource
limits for RLIMIT_MEMLOCK result in an "Operation not permitted"
message.  This is due to bpf limits check return -EPERM.

Instead return -ENOMEM, like most other users of this API.

Fixes: aaac3ba95e4c ("bpf: charge user for creation of BPF maps and programs")
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Fixes: 5ccb071e97fb ("bpf: fix overflow in prog accounting")
Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
---
 kernel/bpf/syscall.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 08a4d287226b..37387a9b0d46 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -85,7 +85,7 @@ int bpf_map_precharge_memlock(u32 pages)
        cur = atomic_long_read(&user->locked_vm);
        free_uid(user);
        if (cur + pages > memlock_limit)
-               return -EPERM;
+               return -ENOMEM;
        return 0;
 }
 
@@ -101,7 +101,7 @@ static int bpf_map_charge_memlock(struct bpf_map *map)
        if (atomic_long_read(&user->locked_vm) > memlock_limit) {
                atomic_long_sub(map->pages, &user->locked_vm);
                free_uid(user);
-               return -EPERM;
+               return -ENOMEM;
        }
        map->user = user;
        return 0;
@@ -658,7 +658,7 @@ int __bpf_prog_charge(struct user_struct *user, u32 pages)
                user_bufs = atomic_long_add_return(pages, &user->locked_vm);
                if (user_bufs > memlock_limit) {
                        atomic_long_sub(pages, &user->locked_vm);
-                       return -EPERM;
+                       return -ENOMEM;
                }
        }