Re: [PATCH bpf-next v2] bpf: Simplify expression for identify bpf mem type

Added BPF_LD_ST_SIZE_MASK macro as mask of size modifier that help to
reduce the evaluation of expressions in if statements,
and remove BPF_SIZE_MASK in netronome driver.

Signed-off-by: Jianlin Lv <redacted>
---
v2: Move the bpf_LD_ST_SIZE_MASK macro definition to include/linux/bpf.h
---
  drivers/net/ethernet/netronome/nfp/bpf/main.h |  8 +++-----
  include/linux/bpf.h                           |  1 +
  kernel/bpf/verifier.c                         | 12 ++++--------
  3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index d0e17eebddd9..e90981e69763 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h

@@ -346,8 +346,6 @@ struct nfp_insn_meta {
  	struct list_head l;
  };
  
-#define BPF_SIZE_MASK	0x18
-
  static inline u8 mbpf_class(const struct nfp_insn_meta *meta)
  {
  	return BPF_CLASS(meta->insn.code);

@@ -375,7 +373,7 @@ static inline bool is_mbpf_alu(const struct nfp_insn_meta *meta)
  
  static inline bool is_mbpf_load(const struct nfp_insn_meta *meta)
  {
-	return (meta->insn.code & ~BPF_SIZE_MASK) == (BPF_LDX | BPF_MEM);
+	return (meta->insn.code & ~BPF_LD_ST_SIZE_MASK) == (BPF_LDX | BPF_MEM);
  }
  
  static inline bool is_mbpf_jmp32(const struct nfp_insn_meta *meta)

@@ -395,7 +393,7 @@ static inline bool is_mbpf_jmp(const struct nfp_insn_meta *meta)
  
  static inline bool is_mbpf_store(const struct nfp_insn_meta *meta)
  {
-	return (meta->insn.code & ~BPF_SIZE_MASK) == (BPF_STX | BPF_MEM);
+	return (meta->insn.code & ~BPF_LD_ST_SIZE_MASK) == (BPF_STX | BPF_MEM);
  }
  
  static inline bool is_mbpf_load_pkt(const struct nfp_insn_meta *meta)

@@ -430,7 +428,7 @@ static inline bool is_mbpf_classic_store_pkt(const struct nfp_insn_meta *meta)
  
  static inline bool is_mbpf_atomic(const struct nfp_insn_meta *meta)
  {
-	return (meta->insn.code & ~BPF_SIZE_MASK) == (BPF_STX | BPF_ATOMIC);
+	return (meta->insn.code & ~BPF_LD_ST_SIZE_MASK) == (BPF_STX | BPF_ATOMIC);
  }
  
  static inline bool is_mbpf_mul(const struct nfp_insn_meta *meta)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a25730eaa148..e85924719c65 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h

@@ -995,6 +995,7 @@ struct bpf_array {
  				 BPF_F_RDONLY_PROG |	\
  				 BPF_F_WRONLY |		\
  				 BPF_F_WRONLY_PROG)
+#define BPF_LD_ST_SIZE_MASK	0x18	/* mask of size modifier */
  
  #define BPF_MAP_CAN_READ	BIT(0)
  #define BPF_MAP_CAN_WRITE	BIT(1)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f9096b049cd6..29fdfdb8abfa 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c

@@ -11384,15 +11384,11 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
  	for (i = 0; i < insn_cnt; i++, insn++) {
  		bpf_convert_ctx_access_t convert_ctx_access;
  
-		if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
-		    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
-		    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
-		    insn->code == (BPF_LDX | BPF_MEM | BPF_DW))
+		/* opcode: BPF_MEM | <size> | BPF_LDX */
+		if ((insn->code & ~BPF_LD_ST_SIZE_MASK) == (BPF_LDX | BPF_MEM))
  			type = BPF_READ;
-		else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
-			 insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
-			 insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
-			 insn->code == (BPF_STX | BPF_MEM | BPF_DW))
+		/* opcode: BPF_MEM | <size> | BPF_STX */
+		else if ((insn->code & ~BPF_LD_ST_SIZE_MASK) == (BPF_STX | BPF_MEM))
  			type = BPF_WRITE;
  		else
  			continue;