net/smc: save state of last sent CDC message

When a link goes down and all connections of this link need to be
switched to an other link then the producer cursor and the sequence of
the last successfully sent CDC message must be known. Add the two fields
to the SMC connection and update it in the tx completion handler.
And to allow matching of sequences in error cases reset the seqno to the
old value in smc_cdc_msg_send() when the actual send failed.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/smc.h b/net/smc/smc.h
index 1a084af..1e91137 100644 (file)
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -143,6 +143,9 @@ struct smc_connection {
                                                 * .prod cf. TCP snd_nxt
                                                 * .cons cf. TCP sends ack
                                                 */
+       union smc_host_cursor   local_tx_ctrl_fin;
+                                               /* prod crsr - confirmed by peer
+                                                */
        union smc_host_cursor   tx_curs_prep;   /* tx - prepared data
                                                 * snd_max..wmem_alloc
                                                 */
@@ -154,6 +157,7 @@ struct smc_connection {
                                                 */
        atomic_t                sndbuf_space;   /* remaining space in sndbuf */
        u16                     tx_cdc_seq;     /* sequence # for CDC send */
+       u16                     tx_cdc_seq_fin; /* sequence # - tx completed */
        spinlock_t              send_lock;      /* protect wr_sends */
        struct delayed_work     tx_work;        /* retry of smc_cdc_msg_send */
        u32                     tx_off;         /* base offset in peer rmb */

diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index f64589d..c5e3329 100644 (file)
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -47,6 +47,9 @@ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
                /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
                smp_mb__after_atomic();
                smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
+               smc_curs_copy(&conn->local_tx_ctrl_fin, &cdcpend->p_cursor,
+                             conn);
+               conn->tx_cdc_seq_fin = cdcpend->ctrl_seq;
        }
        smc_tx_sndbuf_nonfull(smc);
        bh_unlock_sock(&smc->sk);
@@ -104,6 +107,9 @@ int smc_cdc_msg_send(struct smc_connection *conn,
        if (!rc) {
                smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
                conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
+       } else {
+               conn->tx_cdc_seq--;
+               conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
        }
 
        return rc;