diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2017-06-05 12:15:47 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-06 15:41:22 -0400 |
| commit | f3f1c054c288bb6e503005e6d73611151ed20e91 (patch) | |
| tree | ae79e214e4c8ea0d144f69ac8f0bf85b726752c0 /kernel | |
| parent | dc4bb0e2356149aee4cdae061936f3bbdd45595c (diff) | |
bpf: Introduce bpf_map ID
This patch generates an unique ID for each created bpf_map.
The approach is similar to the earlier patch for bpf_prog ID.
It is worth to note that the bpf_map's ID and bpf_prog's ID
are in two independent ID spaces and both have the same valid range:
[1, INT_MAX).
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/syscall.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2a1b32b470f1..4c3075b5d840 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -27,6 +27,8 @@ DEFINE_PER_CPU(int, bpf_prog_active); static DEFINE_IDR(prog_idr); static DEFINE_SPINLOCK(prog_idr_lock); +static DEFINE_IDR(map_idr); +static DEFINE_SPINLOCK(map_idr_lock); int sysctl_unprivileged_bpf_disabled __read_mostly; @@ -117,6 +119,29 @@ static void bpf_map_uncharge_memlock(struct bpf_map *map) free_uid(user); } +static int bpf_map_alloc_id(struct bpf_map *map) +{ + int id; + + spin_lock_bh(&map_idr_lock); + id = idr_alloc_cyclic(&map_idr, map, 1, INT_MAX, GFP_ATOMIC); + if (id > 0) + map->id = id; + spin_unlock_bh(&map_idr_lock); + + if (WARN_ON_ONCE(!id)) + return -ENOSPC; + + return id > 0 ? 0 : id; +} + +static void bpf_map_free_id(struct bpf_map *map) +{ + spin_lock_bh(&map_idr_lock); + idr_remove(&map_idr, map->id); + spin_unlock_bh(&map_idr_lock); +} + /* called from workqueue */ static void bpf_map_free_deferred(struct work_struct *work) { @@ -141,6 +166,7 @@ static void bpf_map_put_uref(struct bpf_map *map) void bpf_map_put(struct bpf_map *map) { if (atomic_dec_and_test(&map->refcnt)) { + bpf_map_free_id(map); INIT_WORK(&map->work, bpf_map_free_deferred); schedule_work(&map->work); } @@ -239,14 +265,20 @@ static int map_create(union bpf_attr *attr) if (err) goto free_map_nouncharge; + err = bpf_map_alloc_id(map); + if (err) + goto free_map; + err = bpf_map_new_fd(map); if (err < 0) /* failed to allocate fd */ - goto free_map; + goto free_id; trace_bpf_map_create(map, err); return err; +free_id: + bpf_map_free_id(map); free_map: bpf_map_uncharge_memlock(map); free_map_nouncharge: |