1 files changed, 63 insertions, 3 deletions

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 9b84d5897a..acca3b1a06 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1149,6 +1149,20 @@ static void smcr_buf_unuse(struct smc_buf_desc *buf_desc, bool is_rmb,
 	}
 }
 
+static void smcd_buf_detach(struct smc_connection *conn)
+{
+	struct smcd_dev *smcd = conn->lgr->smcd;
+	u64 peer_token = conn->peer_token;
+
+	if (!conn->sndbuf_desc)
+		return;
+
+	smc_ism_detach_dmb(smcd, peer_token);
+
+	kfree(conn->sndbuf_desc);
+	conn->sndbuf_desc = NULL;
+}
+
 static void smc_buf_unuse(struct smc_connection *conn,
 			  struct smc_link_group *lgr)
 {
@@ -1192,6 +1206,8 @@ void smc_conn_free(struct smc_connection *conn)
 	if (lgr->is_smcd) {
 		if (!list_empty(&lgr->list))
 			smc_ism_unset_conn(conn);
+		if (smc_ism_support_dmb_nocopy(lgr->smcd))
+			smcd_buf_detach(conn);
 		tasklet_kill(&conn->rx_tsklet);
 	} else {
 		smc_cdc_wait_pend_tx_wr(conn);
@@ -1445,6 +1461,8 @@ static void smc_conn_kill(struct smc_connection *conn, bool soft)
 	smc_sk_wake_ups(smc);
 	if (conn->lgr->is_smcd) {
 		smc_ism_unset_conn(conn);
+		if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))
+			smcd_buf_detach(conn);
 		if (soft)
 			tasklet_kill(&conn->rx_tsklet);
 		else
@@ -1997,7 +2015,6 @@ out:
  */
 static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
 {
-	const unsigned int max_scat = SG_MAX_SINGLE_ALLOC * PAGE_SIZE;
 	u8 compressed;
 
 	if (size <= SMC_BUF_MIN_SIZE)
@@ -2007,9 +2024,11 @@ static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
 	compressed = min_t(u8, ilog2(size) + 1,
 			   is_smcd ? SMCD_DMBE_SIZES : SMCR_RMBE_SIZES);
 
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
 	if (!is_smcd && is_rmb)
 		/* RMBs are backed by & limited to max size of scatterlists */
-		compressed = min_t(u8, compressed, ilog2(max_scat >> 14));
+		compressed = min_t(u8, compressed, ilog2((SG_MAX_SINGLE_ALLOC * PAGE_SIZE) >> 14));
+#endif
 
 	return compressed;
 }
@@ -2464,12 +2483,18 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
 	int rc;
 
 	/* create send buffer */
+	if (is_smcd &&
+	    smc_ism_support_dmb_nocopy(smc->conn.lgr->smcd))
+		goto create_rmb;
+
 	rc = __smc_buf_create(smc, is_smcd, false);
 	if (rc)
 		return rc;
+
+create_rmb:
 	/* create rmb */
 	rc = __smc_buf_create(smc, is_smcd, true);
-	if (rc) {
+	if (rc && smc->conn.sndbuf_desc) {
 		down_write(&smc->conn.lgr->sndbufs_lock);
 		list_del(&smc->conn.sndbuf_desc->list);
 		up_write(&smc->conn.lgr->sndbufs_lock);
@@ -2479,6 +2504,41 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
 	return rc;
 }
 
+int smcd_buf_attach(struct smc_sock *smc)
+{
+	struct smc_connection *conn = &smc->conn;
+	struct smcd_dev *smcd = conn->lgr->smcd;
+	u64 peer_token = conn->peer_token;
+	struct smc_buf_desc *buf_desc;
+	int rc;
+
+	buf_desc = kzalloc(sizeof(*buf_desc), GFP_KERNEL);
+	if (!buf_desc)
+		return -ENOMEM;
+
+	/* The ghost sndbuf_desc describes the same memory region as
+	 * peer RMB. Its lifecycle is consistent with the connection's
+	 * and it will be freed with the connections instead of the
+	 * link group.
+	 */
+	rc = smc_ism_attach_dmb(smcd, peer_token, buf_desc);
+	if (rc)
+		goto free;
+
+	smc->sk.sk_sndbuf = buf_desc->len;
+	buf_desc->cpu_addr =
+		(u8 *)buf_desc->cpu_addr + sizeof(struct smcd_cdc_msg);
+	buf_desc->len -= sizeof(struct smcd_cdc_msg);
+	conn->sndbuf_desc = buf_desc;
+	conn->sndbuf_desc->used = 1;
+	atomic_set(&conn->sndbuf_space, conn->sndbuf_desc->len);
+	return 0;
+
+free:
+	kfree(buf_desc);
+	return rc;
+}
+
 static inline int smc_rmb_reserve_rtoken_idx(struct smc_link_group *lgr)
 {
 	int i;