On Mon, Jul 27, 2020 at 12:22 PM Roman Gushchin <guro@xxxxxx> wrote:
>
> Do not use rlimit-based memory accounting for bpf ringbuffer.
> It has been replaced with the memcg-based memory accounting.
>
> bpf_ringbuf_alloc() can't return anything except ERR_PTR(-ENOMEM)
> and a valid pointer, so to simplify the code make it return NULL
> in the first case. This allows to drop a couple of lines in
> ringbuf_map_alloc() and also makes it look similar to other memory
> allocating function like kmalloc().
>
> Signed-off-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
> ---
> kernel/bpf/ringbuf.c | 24 ++++--------------------
> 1 file changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
> index e8e2c39cbdc9..e687b798d097 100644
> --- a/kernel/bpf/ringbuf.c
> +++ b/kernel/bpf/ringbuf.c
> @@ -48,7 +48,6 @@ struct bpf_ringbuf {
>
> struct bpf_ringbuf_map {
> struct bpf_map map;
> - struct bpf_map_memory memory;
> struct bpf_ringbuf *rb;
> };
>
> @@ -135,7 +134,7 @@ static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node)
>
> rb = bpf_ringbuf_area_alloc(data_sz, numa_node);
> if (!rb)
> - return ERR_PTR(-ENOMEM);
> + return NULL;
>
> spin_lock_init(&rb->spinlock);
> init_waitqueue_head(&rb->waitq);
> @@ -151,8 +150,6 @@ static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node)
> static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr)
> {
> struct bpf_ringbuf_map *rb_map;
> - u64 cost;
> - int err;
>
> if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK)
> return ERR_PTR(-EINVAL);
> @@ -174,26 +171,13 @@ static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr)
>
> bpf_map_init_from_attr(&rb_map->map, attr);
>
> - cost = sizeof(struct bpf_ringbuf_map) +
> - sizeof(struct bpf_ringbuf) +
> - attr->max_entries;
> - err = bpf_map_charge_init(&rb_map->map.memory, cost);
> - if (err)
> - goto err_free_map;
> -
> rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node);
> - if (IS_ERR(rb_map->rb)) {
> - err = PTR_ERR(rb_map->rb);
> - goto err_uncharge;
> + if (!rb_map->rb) {
> + kfree(rb_map);
> + return ERR_PTR(-ENOMEM);
> }
>
> return &rb_map->map;
> -
> -err_uncharge:
> - bpf_map_charge_finish(&rb_map->map.memory);
> -err_free_map:
> - kfree(rb_map);
> - return ERR_PTR(err);
> }
>
> static void bpf_ringbuf_free(struct bpf_ringbuf *rb)
> --
> 2.26.2
>
