net/smc: add SMC-D support in CLC messages

There are two types of SMC: SMC-R and SMC-D. These types are signaled
within the CLC messages during the CLC handshake. This patch adds
support for and checks of the SMC type.

Also, SMC-R and SMC-D need to exchange different information during the
CLC handshake. So, this patch extends the current message formats to
support the SMC-D header fields. The Proposal message can contain both
SMC-R and SMC-D information. The Accept and Confirm messages contain
either SMC-R or SMC-D information.
Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Suggested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -451,14 +451,14 @@ static int smc_check_rdma(struct smc_sock *smc, struct smc_ib_device **ibdev,
 }
 
 /* CLC handshake during connect */
-static int smc_connect_clc(struct smc_sock *smc,
+static int smc_connect_clc(struct smc_sock *smc, int smc_type,
 			   struct smc_clc_msg_accept_confirm *aclc,
 			   struct smc_ib_device *ibdev, u8 ibport)
 {
 	int rc = 0;
 
 	/* do inband token exchange */
-	rc = smc_clc_send_proposal(smc, ibdev, ibport);
+	rc = smc_clc_send_proposal(smc, smc_type, ibdev, ibport, NULL);
 	if (rc)
 		return rc;
 	/* receive SMC Accept CLC message */
@@ -564,7 +564,7 @@ static int __smc_connect(struct smc_sock *smc)
 		return smc_connect_decline_fallback(smc, SMC_CLC_DECL_CNFERR);
 
 	/* perform CLC handshake */
-	rc = smc_connect_clc(smc, &aclc, ibdev, ibport);
+	rc = smc_connect_clc(smc, SMC_TYPE_R, &aclc, ibdev, ibport);
 	if (rc)
 		return smc_connect_decline_fallback(smc, rc);
 
@@ -1008,7 +1008,8 @@ static void smc_listen_work(struct work_struct *work)
 	smc_tx_init(new_smc);
 
 	/* check if RDMA is available */
-	if (smc_check_rdma(new_smc, &ibdev, &ibport) ||
+	if ((pclc->hdr.path != SMC_TYPE_R && pclc->hdr.path != SMC_TYPE_B) ||
+	    smc_check_rdma(new_smc, &ibdev, &ibport) ||
 	    smc_listen_rdma_check(new_smc, pclc) ||
 	    smc_listen_rdma_init(new_smc, pclc, ibdev, ibport,
 				 &local_contact) ||

net/smc/smc_clc.h

@@ -23,6 +23,9 @@
 #define SMC_CLC_DECLINE		0x04
 
 #define SMC_CLC_V1		0x1		/* SMC version                */
+#define SMC_TYPE_R		0		/* SMC-R only		      */
+#define SMC_TYPE_D		1		/* SMC-D only		      */
+#define SMC_TYPE_B		3		/* SMC-R and SMC-D	      */
 #define CLC_WAIT_TIME		(6 * HZ)	/* max. wait time on clcsock  */
 #define SMC_CLC_DECL_MEM	0x01010000  /* insufficient memory resources  */
 #define SMC_CLC_DECL_TIMEOUT	0x02000000  /* timeout                        */
@@ -42,9 +45,11 @@ struct smc_clc_msg_hdr {	/* header1 of clc messages */
 #if defined(__BIG_ENDIAN_BITFIELD)
 	u8 version : 4,
 	   flag    : 1,
-	   rsvd    : 3;
+	   rsvd	   : 1,
+	   path	   : 2;
 #elif defined(__LITTLE_ENDIAN_BITFIELD)
-	u8 rsvd    : 3,
+	u8 path    : 2,
+	   rsvd    : 1,
 	   flag    : 1,
 	   version : 4;
 #endif
@@ -77,6 +82,11 @@ struct smc_clc_msg_proposal_prefix {	/* prefix part of clc proposal message*/
 	u8 ipv6_prefixes_cnt;	/* number of IPv6 prefixes in prefix array */
 } __aligned(4);
 
+struct smc_clc_msg_smcd {	/* SMC-D GID information */
+	u64 gid;		/* ISM GID of requestor */
+	u8 res[32];
+};
+
 struct smc_clc_msg_proposal {	/* clc proposal message sent by Linux */
 	struct smc_clc_msg_hdr hdr;
 	struct smc_clc_msg_local lcl;
@@ -94,23 +104,45 @@ struct smc_clc_msg_proposal {	/* clc proposal message sent by Linux */
 
 struct smc_clc_msg_accept_confirm {	/* clc accept / confirm message */
 	struct smc_clc_msg_hdr hdr;
-	struct smc_clc_msg_local lcl;
-	u8 qpn[3];		/* QP number */
-	__be32 rmb_rkey;	/* RMB rkey */
-	u8 rmbe_idx;		/* Index of RMBE in RMB */
-	__be32 rmbe_alert_token;/* unique connection id */
+	union {
+		struct { /* SMC-R */
+			struct smc_clc_msg_local lcl;
+			u8 qpn[3];		/* QP number */
+			__be32 rmb_rkey;	/* RMB rkey */
+			u8 rmbe_idx;		/* Index of RMBE in RMB */
+			__be32 rmbe_alert_token;/* unique connection id */
 #if defined(__BIG_ENDIAN_BITFIELD)
-	u8 rmbe_size : 4,	/* RMBE buf size (compressed notation) */
-	   qp_mtu   : 4;	/* QP mtu */
+			u8 rmbe_size : 4,	/* buf size (compressed) */
+			   qp_mtu   : 4;	/* QP mtu */
 #elif defined(__LITTLE_ENDIAN_BITFIELD)
-	u8 qp_mtu   : 4,
-	   rmbe_size : 4;
+			u8 qp_mtu   : 4,
+			   rmbe_size : 4;
 #endif
-	u8 reserved;
-	__be64 rmb_dma_addr;	/* RMB virtual address */
-	u8 reserved2;
-	u8 psn[3];		/* initial packet sequence number */
-	struct smc_clc_msg_trail trl; /* eye catcher "SMCR" EBCDIC */
+			u8 reserved;
+			__be64 rmb_dma_addr;	/* RMB virtual address */
+			u8 reserved2;
+			u8 psn[3];		/* packet sequence number */
+			struct smc_clc_msg_trail smcr_trl;
+						/* eye catcher "SMCR" EBCDIC */
+		} __packed;
+		struct { /* SMC-D */
+			u64 gid;		/* Sender GID */
+			u64 token;		/* DMB token */
+			u8 dmbe_idx;		/* DMBE index */
+#if defined(__BIG_ENDIAN_BITFIELD)
+			u8 dmbe_size : 4,	/* buf size (compressed) */
+			   reserved3 : 4;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+			u8 reserved3 : 4,
+			   dmbe_size : 4;
+#endif
+			u16 reserved4;
+			u32 linkid;		/* Link identifier */
+			u32 reserved5[3];
+			struct smc_clc_msg_trail smcd_trl;
+						/* eye catcher "SMCD" EBCDIC */
+		} __packed;
+	};
 } __packed;			/* format defined in RFC7609 */
 
 struct smc_clc_msg_decline {	/* clc decline message */
@@ -129,13 +161,26 @@ smc_clc_proposal_get_prefix(struct smc_clc_msg_proposal *pclc)
 	       ((u8 *)pclc + sizeof(*pclc) + ntohs(pclc->iparea_offset));
 }
 
+/* get SMC-D info from proposal message */
+static inline struct smc_clc_msg_smcd *
+smc_get_clc_msg_smcd(struct smc_clc_msg_proposal *prop)
+{
+	if (ntohs(prop->iparea_offset) != sizeof(struct smc_clc_msg_smcd))
+		return NULL;
+
+	return (struct smc_clc_msg_smcd *)(prop + 1);
+}
+
+struct smcd_dev;
+
 int smc_clc_prfx_match(struct socket *clcsock,
 		       struct smc_clc_msg_proposal_prefix *prop);
 int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
 		     u8 expected_type);
 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info);
-int smc_clc_send_proposal(struct smc_sock *smc, struct smc_ib_device *smcibdev,
-			  u8 ibport);
+int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
+			  struct smc_ib_device *smcibdev, u8 ibport,
+			  struct smcd_dev *ismdev);
 int smc_clc_send_confirm(struct smc_sock *smc);
 int smc_clc_send_accept(struct smc_sock *smc, int srv_first_contact);