Merge branch 'bpf-smap-followups'

Daniel Borkmann says:

====================
Two BPF smap related followups

Fixing preemption imbalance and consolidating prologue
generation. Thanks!
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kernel/bpf/sockmap.c

@@ -135,7 +135,8 @@ static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb)
 	/* Fall through and free skb otherwise */
 	case SK_DROP:
 	default:
-		preempt_enable();
+		if (rc != SK_REDIRECT)
+			preempt_enable();
 		kfree_skb(skb);
 	}
 }

net/core/filter.c

@@ -3455,8 +3455,8 @@ static bool sock_filter_is_valid_access(int off, int size,
 	return true;
 }
 
-static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
-			       const struct bpf_prog *prog)
+static int bpf_unclone_prologue(struct bpf_insn *insn_buf, bool direct_write,
+				const struct bpf_prog *prog, int drop_verdict)
 {
 	struct bpf_insn *insn = insn_buf;
 
@@ -3483,7 +3483,7 @@ static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
 	 * return TC_ACT_SHOT;
 	 */
 	*insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2);
-	*insn++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, TC_ACT_SHOT);
+	*insn++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, drop_verdict);
 	*insn++ = BPF_EXIT_INSN();
 
 	/* restore: */
@@ -3494,6 +3494,12 @@ static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
 	return insn - insn_buf;
 }
 
+static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
+			       const struct bpf_prog *prog)
+{
+	return bpf_unclone_prologue(insn_buf, direct_write, prog, TC_ACT_SHOT);
+}
+
 static bool tc_cls_act_is_valid_access(int off, int size,
 				       enum bpf_access_type type,
 				       struct bpf_insn_access_aux *info)
@@ -3600,40 +3606,7 @@ static bool sock_ops_is_valid_access(int off, int size,
 static int sk_skb_prologue(struct bpf_insn *insn_buf, bool direct_write,
 			   const struct bpf_prog *prog)
 {
-	struct bpf_insn *insn = insn_buf;
-
-	if (!direct_write)
-		return 0;
-
-	/* if (!skb->cloned)
-	 *       goto start;
-	 *
-	 * (Fast-path, otherwise approximation that we might be
-	 *  a clone, do the rest in helper.)
-	 */
-	*insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_6, BPF_REG_1, CLONED_OFFSET());
-	*insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_6, CLONED_MASK);
-	*insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 7);
-
-	/* ret = bpf_skb_pull_data(skb, 0); */
-	*insn++ = BPF_MOV64_REG(BPF_REG_6, BPF_REG_1);
-	*insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_2, BPF_REG_2);
-	*insn++ = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
-			       BPF_FUNC_skb_pull_data);
-	/* if (!ret)
-	 *      goto restore;
-	 * return SK_DROP;
-	 */
-	*insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2);
-	*insn++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, SK_DROP);
-	*insn++ = BPF_EXIT_INSN();
-
-	/* restore: */
-	*insn++ = BPF_MOV64_REG(BPF_REG_1, BPF_REG_6);
-	/* start: */
-	*insn++ = prog->insnsi[0];
-
-	return insn - insn_buf;
+	return bpf_unclone_prologue(insn_buf, direct_write, prog, SK_DROP);
 }
 
 static bool sk_skb_is_valid_access(int off, int size,