tcp_splice: Rename sides of connection from a/b to 0/1

Each spliced connection has two mostly, although not entirely, symmetric
sides.  We currently call those "a" and "b" and have different fields in
the connection structure for each one.

We can better exploit that symmetry if we use two element arrays rather
thatn separately named fields.  Do that in the places we can, and for the
others change the "a"/"b" terminology to 0/1 to match.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 19 insertions, 26 deletions

diff --git a/tcp_conn.h b/tcp_conn.h
index 0751e00..01d31d4 100644
--- a/tcp_conn.h
+++ b/tcp_conn.h
@@ -119,54 +119,47 @@ struct tcp_tap_conn {
 	uint32_t	seq_init_from_tap;
 };
 
+#define SIDES			2
 /**
  * struct tcp_splice_conn - Descriptor for a spliced TCP connection
  * @c:			Fields common with tcp_tap_conn
  * @in_epoll:		Is the connection in the epoll set?
- * @a:			File descriptor number of socket for accepted connection
- * @pipe_a_b:		Pipe ends for splice() from @a to @b
- * @b:			File descriptor number of peer connected socket
- * @pipe_b_a:		Pipe ends for splice() from @b to @a
+ * @s:			File descriptor for sockets
+ * @pipe:		File descriptors for pipes
  * @events:		Events observed/actions performed on connection
  * @flags:		Connection flags (attributes, not events)
- * @a_read:		Bytes read from @a (not fully written to @b in one shot)
- * @a_written:		Bytes written to @a (not fully written from one @b read)
- * @b_read:		Bytes read from @b (not fully written to @a in one shot)
- * @b_written:		Bytes written to @b (not fully written from one @a read)
+ * @read:		Bytes read (not fully written to other side in one shot)
+ * @written:		Bytes written (not fully written from one other side read)
 */
 struct tcp_splice_conn {
 	/* Must be first element to match tcp_tap_conn */
 	struct tcp_conn_common c;
 
 	bool in_epoll	:1;
-	int a;
-	int pipe_a_b[2];
-	int b;
-	int pipe_b_a[2];
+	int s[SIDES];
+	int pipe[SIDES][2];
 
 	uint8_t events;
 #define SPLICE_CLOSED			0
 #define SPLICE_CONNECT			BIT(0)
 #define SPLICE_ESTABLISHED		BIT(1)
-#define A_OUT_WAIT			BIT(2)
-#define B_OUT_WAIT			BIT(3)
-#define A_FIN_RCVD			BIT(4)
-#define B_FIN_RCVD			BIT(5)
-#define A_FIN_SENT			BIT(6)
-#define B_FIN_SENT			BIT(7)
+#define OUT_WAIT_0			BIT(2)
+#define OUT_WAIT_1			BIT(3)
+#define FIN_RCVD_0			BIT(4)
+#define FIN_RCVD_1			BIT(5)
+#define FIN_SENT_0			BIT(6)
+#define FIN_SENT_1			BIT(7)
 
 	uint8_t flags;
 #define SPLICE_V6			BIT(0)
-#define RCVLOWAT_SET_A			BIT(1)
-#define RCVLOWAT_SET_B			BIT(2)
-#define RCVLOWAT_ACT_A			BIT(3)
-#define RCVLOWAT_ACT_B			BIT(4)
+#define RCVLOWAT_SET_0			BIT(1)
+#define RCVLOWAT_SET_1			BIT(2)
+#define RCVLOWAT_ACT_0			BIT(3)
+#define RCVLOWAT_ACT_1			BIT(4)
 #define CLOSING				BIT(5)
 
-	uint32_t a_read;
-	uint32_t a_written;
-	uint32_t b_read;
-	uint32_t b_written;
+	uint32_t read[SIDES];
+	uint32_t written[SIDES];
 };
 
 /**