net: skbuff: move the fields BPF cares about directly next to the offset marker

To avoid more possible BPF dependencies with moving bitfields
around keep the fields BPF cares about right next to the offset
marker.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230321014115.997841-4-kuba@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 36d31e7..6aeb0e7 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -947,15 +947,15 @@ struct sk_buff {
        /* private: */
        __u8                    __mono_tc_offset[0];
        /* public: */
-       __u8                    remcsum_offload:1;
-       __u8                    csum_complete_sw:1;
-       __u8                    csum_level:2;
-       __u8                    dst_pending_confirm:1;
        __u8                    mono_delivery_time:1;   /* See SKB_MONO_DELIVERY_TIME_MASK */
 #ifdef CONFIG_NET_CLS_ACT
-       __u8                    tc_skip_classify:1;
        __u8                    tc_at_ingress:1;        /* See TC_AT_INGRESS_MASK */
+       __u8                    tc_skip_classify:1;
 #endif
+       __u8                    remcsum_offload:1;
+       __u8                    csum_complete_sw:1;
+       __u8                    csum_level:2;
+       __u8                    dst_pending_confirm:1;
 
        __u8                    l4_hash:1;
        __u8                    sw_hash:1;
@@ -1072,11 +1072,11 @@ struct sk_buff {
  * around, you also must adapt these constants.
  */
 #ifdef __BIG_ENDIAN_BITFIELD
-#define TC_AT_INGRESS_MASK             (1 << 0)
-#define SKB_MONO_DELIVERY_TIME_MASK    (1 << 2)
+#define SKB_MONO_DELIVERY_TIME_MASK    (1 << 7)
+#define TC_AT_INGRESS_MASK             (1 << 6)
 #else
-#define TC_AT_INGRESS_MASK             (1 << 7)
-#define SKB_MONO_DELIVERY_TIME_MASK    (1 << 5)
+#define SKB_MONO_DELIVERY_TIME_MASK    (1 << 0)
+#define TC_AT_INGRESS_MASK             (1 << 1)
 #endif
 #define SKB_BF_MONO_TC_OFFSET          offsetof(struct sk_buff, __mono_tc_offset)
 

diff --git a/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
index ae7b6e5..4951aa9 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
+++ b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
@@ -69,15 +69,15 @@ static struct test_case test_cases[] = {
        {
                N(SCHED_CLS, struct __sk_buff, tstamp),
                .read  = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
-                        "w11 &= 160;"
-                        "if w11 != 0xa0 goto pc+2;"
+                        "w11 &= 3;"
+                        "if w11 != 0x3 goto pc+2;"
                         "$dst = 0;"
                         "goto pc+1;"
                         "$dst = *(u64 *)($ctx + sk_buff::tstamp);",
                .write = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
-                        "if w11 & 0x80 goto pc+1;"
+                        "if w11 & 0x2 goto pc+1;"
                         "goto pc+2;"
-                        "w11 &= -33;"
+                        "w11 &= -2;"
                         "*(u8 *)($ctx + sk_buff::__mono_tc_offset) = r11;"
                         "*(u64 *)($ctx + sk_buff::tstamp) = $src;",
        },