Merge branch 'bpf_iter-fixes'

Yonghong Song says:

====================
Commit ae24345da54e ("bpf: Implement an interface to register
bpf_iter targets") and its subsequent commits in the same patch set
introduced bpf iterator, a way to run bpf program when iterating
kernel data structures.

This patch set addressed some followup issues. One big change
is to allow target to pass ctx arg register types to verifier
for verification purpose. Please see individual patch for details.

Changelogs:
  v1 -> v2:
    . add "const" qualifier to struct bpf_iter_reg for
      bpf_iter_[un]reg_target, and this results in
      additional "const" qualifiers in some other places
    . drop the patch which will issue WARN_ONCE if
      seq_ops->show() returns a positive value.
      If this does happen, code review should spot
      this or author does know what he is doing.
      In the future, we do want to implement a
      mechanism to find out all registered targets
      so we will be aware of new additions.
====================

Acked-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>

1 files changed, 16 insertions, 6 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cf4b6e44f2bc..c45d198ac38c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -643,6 +643,12 @@ struct bpf_jit_poke_descriptor {
 	u16 reason;
 };
 
+/* reg_type info for ctx arguments */
+struct bpf_ctx_arg_aux {
+	u32 offset;
+	enum bpf_reg_type reg_type;
+};
+
 struct bpf_prog_aux {
 	atomic64_t refcnt;
 	u32 used_map_cnt;
@@ -654,12 +660,13 @@ struct bpf_prog_aux {
 	u32 func_cnt; /* used by non-func prog as the number of func progs */
 	u32 func_idx; /* 0 for non-func prog, the index in func array for func prog */
 	u32 attach_btf_id; /* in-kernel BTF type id to attach to */
+	u32 ctx_arg_info_size;
+	const struct bpf_ctx_arg_aux *ctx_arg_info;
 	struct bpf_prog *linked_prog;
 	bool verifier_zext; /* Zero extensions has been inserted by verifier. */
 	bool offload_requested;
 	bool attach_btf_trace; /* true if attaching to BTF-enabled raw tp */
 	bool func_proto_unreliable;
-	bool btf_id_or_null_non0_off;
 	enum bpf_tramp_prog_type trampoline_prog_type;
 	struct bpf_trampoline *trampoline;
 	struct hlist_node tramp_hlist;
@@ -1131,20 +1138,23 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd);
 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
 int bpf_obj_get_user(const char __user *pathname, int flags);
 
-#define BPF_ITER_FUNC_PREFIX "__bpf_iter__"
+#define BPF_ITER_FUNC_PREFIX "bpf_iter_"
 #define DEFINE_BPF_ITER_FUNC(target, args...)			\
-	extern int __bpf_iter__ ## target(args);		\
-	int __init __bpf_iter__ ## target(args) { return 0; }
+	extern int bpf_iter_ ## target(args);			\
+	int __init bpf_iter_ ## target(args) { return 0; }
 
 typedef int (*bpf_iter_init_seq_priv_t)(void *private_data);
 typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data);
 
+#define BPF_ITER_CTX_ARG_MAX 2
 struct bpf_iter_reg {
 	const char *target;
 	const struct seq_operations *seq_ops;
 	bpf_iter_init_seq_priv_t init_seq_private;
 	bpf_iter_fini_seq_priv_t fini_seq_private;
 	u32 seq_priv_size;
+	u32 ctx_arg_info_size;
+	struct bpf_ctx_arg_aux ctx_arg_info[BPF_ITER_CTX_ARG_MAX];
 };
 
 struct bpf_iter_meta {
@@ -1153,8 +1163,8 @@ struct bpf_iter_meta {
 	u64 seq_num;
 };
 
-int bpf_iter_reg_target(struct bpf_iter_reg *reg_info);
-void bpf_iter_unreg_target(const char *target);
+int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info);
+void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info);
 bool bpf_iter_prog_supported(struct bpf_prog *prog);
 int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
 int bpf_iter_new_fd(struct bpf_link *link);