[PATCH stable linux-5.15.y 06/10] bpf: Convert PTR_TO_MEM_OR_NULL to composable types.

[Hao Luo <haoluo@google.com>]

commit cf9f2f8d62eca810afbd1ee6cc0800202b000e57 upstream.

Remove PTR_TO_MEM_OR_NULL and replace it with PTR_TO_MEM combined with
flag PTR_MAYBE_NULL.

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211217003152.48334-7-haoluo@google.com
Cc: stable@vger.kernel.org # 5.15.x
---
 include/linux/bpf.h   | 1 -
 kernel/bpf/btf.c      | 2 +-
 kernel/bpf/verifier.c | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 83c28c683b6d..1cb5aae0fcb6 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -502,7 +502,6 @@ enum bpf_reg_type {
 	PTR_TO_SOCK_COMMON_OR_NULL	= PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
 	PTR_TO_TCP_SOCK_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
 	PTR_TO_BTF_ID_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_BTF_ID,
-	PTR_TO_MEM_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_MEM,
 
 	/* This must be the last entry. Its purpose is to ensure the enum is
 	 * wide enough to hold the higher bits reserved for bpf_type_flag.
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 9247dfcde054..c2ecea3c16e0 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5719,7 +5719,7 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
 				return -EINVAL;
 			}
 
-			reg->type = PTR_TO_MEM_OR_NULL;
+			reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
 			reg->id = ++env->id_gen;
 
 			continue;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0de4a9458bf7..0aff2e4976d6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13135,7 +13135,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog)
 				mark_reg_known_zero(env, regs, i);
 			else if (regs[i].type == SCALAR_VALUE)
 				mark_reg_unknown(env, regs, i);
-			else if (regs[i].type == PTR_TO_MEM_OR_NULL) {
+			else if (base_type(regs[i].type) == PTR_TO_MEM) {
 				const u32 mem_size = regs[i].mem_size;
 
 				mark_reg_known_zero(env, regs, i);
-- 
2.36.0.464.gb9c8b46e94-goog