net/smc: urgent data support
Add support for out of band data send and receive.
Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 290a434..3d77b38 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -47,16 +47,59 @@
* @conn connection to update
* @cons consumer cursor
* @len number of Bytes consumed
+ * Returns:
+ * 1 if we should end our receive, 0 otherwise
*/
-static void smc_rx_update_consumer(struct smc_connection *conn,
- union smc_host_cursor cons, size_t len)
+static int smc_rx_update_consumer(struct smc_sock *smc,
+ union smc_host_cursor cons, size_t len)
{
+ struct smc_connection *conn = &smc->conn;
+ struct sock *sk = &smc->sk;
+ bool force = false;
+ int diff, rc = 0;
+
smc_curs_add(conn->rmb_desc->len, &cons, len);
+
+ /* did we process urgent data? */
+ if (conn->urg_state == SMC_URG_VALID || conn->urg_rx_skip_pend) {
+ diff = smc_curs_comp(conn->rmb_desc->len, &cons,
+ &conn->urg_curs);
+ if (sock_flag(sk, SOCK_URGINLINE)) {
+ if (diff == 0) {
+ force = true;
+ rc = 1;
+ conn->urg_state = SMC_URG_READ;
+ }
+ } else {
+ if (diff == 1) {
+ /* skip urgent byte */
+ force = true;
+ smc_curs_add(conn->rmb_desc->len, &cons, 1);
+ conn->urg_rx_skip_pend = false;
+ } else if (diff < -1)
+ /* we read past urgent byte */
+ conn->urg_state = SMC_URG_READ;
+ }
+ }
+
smc_curs_write(&conn->local_tx_ctrl.cons, smc_curs_read(&cons, conn),
conn);
+
/* send consumer cursor update if required */
/* similar to advertising new TCP rcv_wnd if required */
- smc_tx_consumer_update(conn);
+ smc_tx_consumer_update(conn, force);
+
+ return rc;
+}
+
+static void smc_rx_update_cons(struct smc_sock *smc, size_t len)
+{
+ struct smc_connection *conn = &smc->conn;
+ union smc_host_cursor cons;
+
+ smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn),
+ conn);
+ smc_rx_update_consumer(smc, cons, len);
}
struct smc_spd_priv {
@@ -70,7 +113,6 @@
struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private;
struct smc_sock *smc = priv->smc;
struct smc_connection *conn;
- union smc_host_cursor cons;
struct sock *sk = &smc->sk;
if (sk->sk_state == SMC_CLOSED ||
@@ -79,9 +121,7 @@
goto out;
conn = &smc->conn;
lock_sock(sk);
- smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn),
- conn);
- smc_rx_update_consumer(conn, cons, priv->len);
+ smc_rx_update_cons(smc, priv->len);
release_sock(sk);
if (atomic_sub_and_test(priv->len, &conn->splice_pending))
smc_rx_wake_up(sk);
@@ -184,6 +224,52 @@
return rc;
}
+static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len,
+ int flags)
+{
+ struct smc_connection *conn = &smc->conn;
+ union smc_host_cursor cons;
+ struct sock *sk = &smc->sk;
+ int rc = 0;
+
+ if (sock_flag(sk, SOCK_URGINLINE) ||
+ !(conn->urg_state == SMC_URG_VALID) ||
+ conn->urg_state == SMC_URG_READ)
+ return -EINVAL;
+
+ if (conn->urg_state == SMC_URG_VALID) {
+ if (!(flags & MSG_PEEK))
+ smc->conn.urg_state = SMC_URG_READ;
+ msg->msg_flags |= MSG_OOB;
+ if (len > 0) {
+ if (!(flags & MSG_TRUNC))
+ rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1);
+ len = 1;
+ smc_curs_write(&cons,
+ smc_curs_read(&conn->local_tx_ctrl.cons,
+ conn),
+ conn);
+ if (smc_curs_diff(conn->rmb_desc->len, &cons,
+ &conn->urg_curs) > 1)
+ conn->urg_rx_skip_pend = true;
+ /* Urgent Byte was already accounted for, but trigger
+ * skipping the urgent byte in non-inline case
+ */
+ if (!(flags & MSG_PEEK))
+ smc_rx_update_consumer(smc, cons, 0);
+ } else {
+ msg->msg_flags |= MSG_TRUNC;
+ }
+
+ return rc ? -EFAULT : len;
+ }
+
+ if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN)
+ return 0;
+
+ return -EAGAIN;
+}
+
/* smc_rx_recvmsg - receive data from RMBE
* @msg: copy data to receive buffer
* @pipe: copy data to pipe if set - indicates splice() call
@@ -209,12 +295,12 @@
if (unlikely(flags & MSG_ERRQUEUE))
return -EINVAL; /* future work for sk.sk_family == AF_SMC */
- if (flags & MSG_OOB)
- return -EINVAL; /* future work */
sk = &smc->sk;
if (sk->sk_state == SMC_LISTEN)
return -ENOTCONN;
+ if (flags & MSG_OOB)
+ return smc_rx_recv_urg(smc, msg, len, flags);
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
@@ -227,6 +313,9 @@
if (atomic_read(&conn->bytes_to_rcv))
goto copy;
+ else if (conn->urg_state == SMC_URG_VALID)
+ /* we received a single urgent Byte - skip */
+ smc_rx_update_cons(smc, 0);
if (sk->sk_shutdown & RCV_SHUTDOWN ||
smc_cdc_rxed_any_close_or_senddone(conn) ||
@@ -281,14 +370,18 @@
continue;
}
- /* not more than what user space asked for */
- copylen = min_t(size_t, read_remaining, readable);
smc_curs_write(&cons,
smc_curs_read(&conn->local_tx_ctrl.cons, conn),
conn);
/* subsequent splice() calls pick up where previous left */
if (splbytes)
smc_curs_add(conn->rmb_desc->len, &cons, splbytes);
+ if (conn->urg_state == SMC_URG_VALID &&
+ sock_flag(&smc->sk, SOCK_URGINLINE) &&
+ readable > 1)
+ readable--; /* always stop at urgent Byte */
+ /* not more than what user space asked for */
+ copylen = min_t(size_t, read_remaining, readable);
/* determine chunks where to read from rcvbuf */
/* either unwrapped case, or 1st chunk of wrapped case */
chunk_len = min_t(size_t, copylen, conn->rmb_desc->len -
@@ -333,8 +426,8 @@
atomic_sub(copylen, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
smp_mb__after_atomic();
- if (msg)
- smc_rx_update_consumer(conn, cons, copylen);
+ if (msg && smc_rx_update_consumer(smc, cons, copylen))
+ goto out;
}
} while (read_remaining);
out:
@@ -346,4 +439,5 @@
{
smc->sk.sk_data_ready = smc_rx_wake_up;
atomic_set(&smc->conn.splice_pending, 0);
+ smc->conn.urg_state = SMC_URG_READ;
}