3 files changed, 47 insertions, 0 deletions

diff --git a/include/net/smc.h b/include/net/smc.h
index 33b753115e43..db84e4e35080 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -74,6 +74,9 @@ struct smcd_ops {
 	int (*reset_vlan_required)(struct smcd_dev *dev);
 	int (*signal_event)(struct smcd_dev *dev, struct smcd_gid *rgid,
 			    u32 trigger_irq, u32 event_code, u64 info);
+	int (*support_dmb_nocopy)(struct smcd_dev *dev);
+	int (*attach_dmb)(struct smcd_dev *dev, struct smcd_dmb *dmb);
+	int (*detach_dmb)(struct smcd_dev *dev, u64 token);
 };
 
 struct smcd_dev {
diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index 6bed0a61b746..84f98e18c7db 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -250,6 +250,46 @@ int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
 	return rc;
 }
 
+bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd)
+{
+	/* for now only loopback-ism supports
+	 * merging sndbuf with peer DMB to avoid
+	 * data copies between them.
+	 */
+	return (smcd->ops->support_dmb_nocopy &&
+		smcd->ops->support_dmb_nocopy(smcd));
+}
+
+int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token,
+		       struct smc_buf_desc *dmb_desc)
+{
+	struct smcd_dmb dmb;
+	int rc = 0;
+
+	if (!dev->ops->attach_dmb)
+		return -EINVAL;
+
+	memset(&dmb, 0, sizeof(dmb));
+	dmb.dmb_tok = token;
+	rc = dev->ops->attach_dmb(dev, &dmb);
+	if (!rc) {
+		dmb_desc->sba_idx = dmb.sba_idx;
+		dmb_desc->token = dmb.dmb_tok;
+		dmb_desc->cpu_addr = dmb.cpu_addr;
+		dmb_desc->dma_addr = dmb.dma_addr;
+		dmb_desc->len = dmb.dmb_len;
+	}
+	return rc;
+}
+
+int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token)
+{
+	if (!dev->ops->detach_dmb)
+		return -EINVAL;
+
+	return dev->ops->detach_dmb(dev, token);
+}
+
 static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
 				  struct sk_buff *skb,
 				  struct netlink_callback *cb)
diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
index e6f57e5e1ef9..6763133dd8d0 100644
--- a/net/smc/smc_ism.h
+++ b/net/smc/smc_ism.h
@@ -48,6 +48,10 @@ int smc_ism_put_vlan(struct smcd_dev *dev, unsigned short vlan_id);
 int smc_ism_register_dmb(struct smc_link_group *lgr, int buf_size,
 			 struct smc_buf_desc *dmb_desc);
 int smc_ism_unregister_dmb(struct smcd_dev *dev, struct smc_buf_desc *dmb_desc);
+bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd);
+int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token,
+		       struct smc_buf_desc *dmb_desc);
+int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token);
 int smc_ism_signal_shutdown(struct smc_link_group *lgr);
 void smc_ism_get_system_eid(u8 **eid);
 u16 smc_ism_get_chid(struct smcd_dev *dev);