[PATCH v2 net-next 2/8] bpf: Introduce bpf_map ID
From: Martin KaFai Lau <hidden>
Date: 2017-05-31 18:59:35
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
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 <redacted> Acked-by: Alexei Starovoitov <redacted> Acked-by: Daniel Borkmann <daniel@iogearbox.net> --- include/linux/bpf.h | 1 + kernel/bpf/syscall.c | 34 +++++++++++++++++++++++++++++++++- 2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c2793a732edc..ea78d87cbc3e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h@@ -46,6 +46,7 @@ struct bpf_map { u32 max_entries; u32 map_flags; u32 pages; + u32 id; struct user_struct *user; const struct bpf_map_ops *ops; struct work_struct work;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4a936b08a4b0..20f392d64f49 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:
--
2.9.3