To allow better problem diagnosis the return codes for SMC-Dv2 are
improved by this patch. A few more CLC DECLINE codes are defined and
sent to the peer when an SMC connection cannot be established.
There are now multiple SMC variations that are offered by the client and
the server may encounter problems to initialize all of them.
Because only one diagnosis code can be sent to the client the decision
was made to send the first code that was encountered. Because the server
tries the variations in the order of importance (SMC-Dv2, SMC-D, SMC-R)
this makes sure that the diagnosis code of the most important variation
is sent.

Signed-off-by: Karsten Graul <redacted>
---
 net/smc/af_smc.c   | 61 +++++++++++++++++++++++++++++++---------------
 net/smc/smc_clc.h  |  5 ++++
 net/smc/smc_core.h |  1 +
 3 files changed, 47 insertions(+), 20 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 82be0bd0f6e8..5414704f4cac 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c

@@ -1346,6 +1346,7 @@ static int smc_listen_v2_check(struct smc_sock *new_smc,
 {
 	struct smc_clc_smcd_v2_extension *pclc_smcd_v2_ext;
 	struct smc_clc_v2_extension *pclc_v2_ext;
+	int rc;
 
 	ini->smc_type_v1 = pclc->hdr.typev1;
 	ini->smc_type_v2 = pclc->hdr.typev2;

@@ -1353,29 +1354,30 @@ static int smc_listen_v2_check(struct smc_sock *new_smc,
 	if (pclc->hdr.version > SMC_V1)
 		ini->smcd_version |=
 				ini->smc_type_v2 != SMC_TYPE_N ? SMC_V2 : 0;
+	if (!(ini->smcd_version & SMC_V2)) {
+		rc = SMC_CLC_DECL_PEERNOSMC;
+		goto out;
+	}
 	if (!smc_ism_v2_capable) {
 		ini->smcd_version &= ~SMC_V2;
+		rc = SMC_CLC_DECL_NOISM2SUPP;
 		goto out;
 	}
 	pclc_v2_ext = smc_get_clc_v2_ext(pclc);
 	if (!pclc_v2_ext) {
 		ini->smcd_version &= ~SMC_V2;
+		rc = SMC_CLC_DECL_NOV2EXT;
 		goto out;
 	}
 	pclc_smcd_v2_ext = smc_get_clc_smcd_v2_ext(pclc_v2_ext);
-	if (!pclc_smcd_v2_ext)
+	if (!pclc_smcd_v2_ext) {
 		ini->smcd_version &= ~SMC_V2;
+		rc = SMC_CLC_DECL_NOV2DEXT;
+	}
 
 out:
-	if (!ini->smcd_version) {
-		if (pclc->hdr.typev1 == SMC_TYPE_B ||
-		    pclc->hdr.typev2 == SMC_TYPE_B)
-			return SMC_CLC_DECL_NOSMCDEV;
-		if (pclc->hdr.typev1 == SMC_TYPE_D ||
-		    pclc->hdr.typev2 == SMC_TYPE_D)
-			return SMC_CLC_DECL_NOSMCDDEV;
-		return SMC_CLC_DECL_NOSMCRDEV;
-	}
+	if (!ini->smcd_version)
+		return rc;

 
 	return 0;
 }

@@ -1473,6 +1475,12 @@ static void smc_check_ism_v2_match(struct smc_init_info *ini,
 	}
 }

@@ -1630,10 +1647,14 @@ static int smc_listen_find_device(struct smc_sock *new_smc,
 		return 0;
 
 	if (pclc->hdr.typev1 == SMC_TYPE_D)
-		return SMC_CLC_DECL_NOSMCDDEV; /* skip RDMA and decline */
+		/* skip RDMA and decline */
+		return ini->rc ?: SMC_CLC_DECL_NOSMCDDEV;
 
 	/* check if RDMA is available */
-	return smc_find_rdma_v1_device_serv(new_smc, pclc, ini);
+	rc = smc_find_rdma_v1_device_serv(new_smc, pclc, ini);
+	smc_find_ism_store_rc(rc, ini);
+
+	return (!rc) ? 0 : ini->rc;