Re: [PATCH RFC bpf-next v2 01/18] bpf: Register rhash map

["Emil Tsalapatis" <emil@etsalapatis.com>]

On Wed Apr 8, 2026 at 11:10 AM EDT, Mykyta Yatsenko wrote:
> From: Mykyta Yatsenko <yatsenko@meta.com>
>
> Add resizable hash map into enums where it is needed.
>

These changes in isolation are difficult to reason about,
can we roll this into subsequent patches? Right now this
adds a the BPF_MAP_TYPE_RHASH without there being a way
to create one.

> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
> ---
>  include/uapi/linux/bpf.h       | 1 +
>  kernel/bpf/map_iter.c          | 3 ++-
>  kernel/bpf/syscall.c           | 3 +++
>  kernel/bpf/verifier.c          | 1 +
>  tools/include/uapi/linux/bpf.h | 1 +
>  5 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 552bc5d9afbd..822582c04f22 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1046,6 +1046,7 @@ enum bpf_map_type {
>  	BPF_MAP_TYPE_CGRP_STORAGE,
>  	BPF_MAP_TYPE_ARENA,
>  	BPF_MAP_TYPE_INSN_ARRAY,
> +	BPF_MAP_TYPE_RHASH,
>  	__MAX_BPF_MAP_TYPE
>  };
>  
> diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
> index 261a03ea73d3..4a2aafbe28b4 100644
> --- a/kernel/bpf/map_iter.c
> +++ b/kernel/bpf/map_iter.c
> @@ -119,7 +119,8 @@ static int bpf_iter_attach_map(struct bpf_prog *prog,
>  		is_percpu = true;
>  	else if (map->map_type != BPF_MAP_TYPE_HASH &&
>  		 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
> -		 map->map_type != BPF_MAP_TYPE_ARRAY)
> +		 map->map_type != BPF_MAP_TYPE_ARRAY &&
> +		 map->map_type != BPF_MAP_TYPE_RHASH)
>  		goto put_map;
>  
>  	key_acc_size = prog->aux->max_rdonly_access;
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 51ade3cde8bb..0a5ec417638d 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -1287,6 +1287,7 @@ static int map_check_btf(struct bpf_map *map, struct bpf_token *token,
>  			case BPF_SPIN_LOCK:
>  			case BPF_RES_SPIN_LOCK:
>  				if (map->map_type != BPF_MAP_TYPE_HASH &&
> +				    map->map_type != BPF_MAP_TYPE_RHASH &&
>  				    map->map_type != BPF_MAP_TYPE_ARRAY &&
>  				    map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
>  				    map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
> @@ -1464,6 +1465,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
>  	case BPF_MAP_TYPE_CGROUP_ARRAY:
>  	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
>  	case BPF_MAP_TYPE_HASH:
> +	case BPF_MAP_TYPE_RHASH:
>  	case BPF_MAP_TYPE_PERCPU_HASH:
>  	case BPF_MAP_TYPE_HASH_OF_MAPS:
>  	case BPF_MAP_TYPE_RINGBUF:
> @@ -2199,6 +2201,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr)
>  		   map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
>  		   map->map_type == BPF_MAP_TYPE_LRU_HASH ||
>  		   map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
> +		   map->map_type == BPF_MAP_TYPE_RHASH ||
>  		   map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
>  		if (!bpf_map_is_offloaded(map)) {
>  			bpf_disable_instrumentation();
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 8c1cf2eb6cbb..53523ab953c2 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -21816,6 +21816,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
>  	if (prog->sleepable)
>  		switch (map->map_type) {
>  		case BPF_MAP_TYPE_HASH:
> +		case BPF_MAP_TYPE_RHASH:
>  		case BPF_MAP_TYPE_LRU_HASH:
>  		case BPF_MAP_TYPE_ARRAY:
>  		case BPF_MAP_TYPE_PERCPU_HASH:
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 677be9a47347..9d7df174770a 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -1046,6 +1046,7 @@ enum bpf_map_type {
>  	BPF_MAP_TYPE_CGRP_STORAGE,
>  	BPF_MAP_TYPE_ARENA,
>  	BPF_MAP_TYPE_INSN_ARRAY,
> +	BPF_MAP_TYPE_RHASH,
>  	__MAX_BPF_MAP_TYPE
>  };
>