[PATCH net-next 2/9] nfp: bpf: refactor nfp_bpf_check_ptr()

[Jakub Kicinski]

nfp_bpf_check_ptr() mostly looks at the pointer register.
Add a temporary variable to shorten the code.

While at it make sure we print error messages if translation
fails to help users identify the problem (to be carried in
ext_ack in due course).

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Quentin Monnet <quentin.mon...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c 
b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index e361c0e3b788..4d2ed84a82e0 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -113,17 +113,23 @@ nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
 
 static int
 nfp_bpf_check_ptr(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
-                 const struct bpf_verifier_env *env, u8 reg)
+                 const struct bpf_verifier_env *env, u8 reg_no)
 {
-       if (env->cur_state.regs[reg].type != PTR_TO_CTX &&
-           env->cur_state.regs[reg].type != PTR_TO_PACKET)
+       const struct bpf_reg_state *reg = &env->cur_state.regs[reg_no];
+
+       if (reg->type != PTR_TO_CTX &&
+           reg->type != PTR_TO_PACKET) {
+               pr_info("unsupported ptr type: %d\n", reg->type);
                return -EINVAL;
+       }
 
-       if (meta->ptr.type != NOT_INIT &&
-           meta->ptr.type != env->cur_state.regs[reg].type)
+       if (meta->ptr.type != NOT_INIT && meta->ptr.type != reg->type) {
+               pr_info("ptr type changed for instruction %d -> %d\n",
+                       meta->ptr.type, reg->type);
                return -EINVAL;
+       }
 
-       meta->ptr = env->cur_state.regs[reg];
+       meta->ptr = *reg;
 
        return 0;
 }
-- 
2.14.1