libbpf: Support resizable hashtable

Add BPF_MAP_TYPE_RHASH to libbpf's map type name table and feature
probing so that libbpf-based tools can create and identify resizable
hash maps.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260605-rhash-v7-8-5b8e05f8630d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

src/libbpf.c

@@ -192,6 +192,7 @@ static const char * const map_type_name[] = {
 	[BPF_MAP_TYPE_CGRP_STORAGE]		= "cgrp_storage",
 	[BPF_MAP_TYPE_ARENA]			= "arena",
 	[BPF_MAP_TYPE_INSN_ARRAY]		= "insn_array",
+	[BPF_MAP_TYPE_RHASH]			= "rhash",
 };
 
 static const char * const prog_type_name[] = {

src/libbpf_probes.c

@@ -309,6 +309,9 @@ static int probe_map_create(enum bpf_map_type map_type)
 		value_size	= sizeof(__u64);
 		opts.map_flags	= BPF_F_NO_PREALLOC;
 		break;
+	case BPF_MAP_TYPE_RHASH:
+		opts.map_flags	= BPF_F_NO_PREALLOC;
+		break;
 	case BPF_MAP_TYPE_CGROUP_STORAGE:
 	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
 		key_size	= sizeof(struct bpf_cgroup_storage_key);