[PATCH net-next v2 0/2] net/smc: improve peer ID in CLC decline

[PATCH net-next v2 0/2] net/smc: improve peer ID in CLC decline

[Hans Wippel]

The following two patches improve the peer ID in CLC decline messages if
RoCE devices are present in the host but no suitable device is found for
a connection. The first patch reworks the peer ID initialization. The
second patch contains the actual changes of the CLC decline messages.

Changes v1 -> v2:
* make smc_ib_is_valid_local_systemid() static in first patch
* changed if in smc_clc_send_decline() to remove curly braces

Changes RFC -> v1:
* split the patch into two parts
* removed zero assignment to global variable (thanks Leon)

Thanks to Leon Romanovsky and Karsten Graul for the feedback!

Hans Wippel (2):
  net/smc: rework peer ID handling
  net/smc: improve peer ID in CLC decline for SMC-R

 net/smc/smc_clc.c |  3 ++-
 net/smc/smc_ib.c  | 19 ++++++++++++-------
 net/smc/smc_ib.h  |  1 +
 3 files changed, 15 insertions(+), 8 deletions(-)

-- 
2.25.1

[PATCH net-next v2 1/2] net/smc: rework peer ID handling

[Hans Wippel]

This patch initializes the peer ID to a random instance ID and a zero
MAC address. If a RoCE device is in the host, the MAC address part of
the peer ID is overwritten with the respective address. Also, a function
for checking if the peer ID is valid is added. A peer ID is considered
valid if the MAC address part contains a non-zero MAC address.

Signed-off-by: Hans Wippel <ndev@hwipl.net>
---
 net/smc/smc_ib.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 6756bd5a3fe4..e0592d337a94 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -37,11 +37,7 @@ struct smc_ib_devices smc_ib_devices = {	/* smc-registered ib devices */
 	.list = LIST_HEAD_INIT(smc_ib_devices.list),
 };
 
-#define SMC_LOCAL_SYSTEMID_RESET	"%%%%%%%"
-
-u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET;	/* unique system
-								 * identifier
-								 */
+u8 local_systemid[SMC_SYSTEMID_LEN];		/* unique system identifier */
 
 static int smc_ib_modify_qp_init(struct smc_link *lnk)
 {
@@ -168,6 +164,15 @@ static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
 {
 	memcpy(&local_systemid[2], &smcibdev->mac[ibport - 1],
 	       sizeof(smcibdev->mac[ibport - 1]));
+}
+
+static bool smc_ib_is_valid_local_systemid(void)
+{
+	return !is_zero_ether_addr(&local_systemid[2]);
+}
+
+static void smc_ib_init_local_systemid(void)
+{
 	get_random_bytes(&local_systemid[0], 2);
 }
 
@@ -224,8 +229,7 @@ static int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport)
 	rc = smc_ib_fill_mac(smcibdev, ibport);
 	if (rc)
 		goto out;
-	if (!strncmp(local_systemid, SMC_LOCAL_SYSTEMID_RESET,
-		     sizeof(local_systemid)) &&
+	if (!smc_ib_is_valid_local_systemid() &&
 	    smc_ib_port_active(smcibdev, ibport))
 		/* create unique system identifier */
 		smc_ib_define_local_systemid(smcibdev, ibport);
@@ -605,6 +609,7 @@ static struct ib_client smc_ib_client = {
 
 int __init smc_ib_register_client(void)
 {
+	smc_ib_init_local_systemid();
 	return ib_register_client(&smc_ib_client);
 }
 
-- 
2.25.1

[PATCH net-next v2 2/2] net/smc: improve peer ID in CLC decline for SMC-R

[Hans Wippel]

According to RFC 7609, all CLC messages contain a peer ID that consists
of a unique instance ID and the MAC address of one of the host's RoCE
devices. But if a SMC-R connection cannot be established, e.g., because
no matching pnet table entry is found, the current implementation uses a
zero value in the CLC decline message although the host's peer ID is set
to a proper value.

If no RoCE and no ISM device is usable for a connection, there is no LGR
and the LGR check in smc_clc_send_decline() prevents that the peer ID is
copied into the CLC decline message for both SMC-D and SMC-R. So, this
patch modifies the check to also accept the case of no LGR. Also, only a
valid peer ID is copied into the decline message.

Signed-off-by: Hans Wippel <ndev@hwipl.net>
---
 net/smc/smc_clc.c | 3 ++-
 net/smc/smc_ib.c  | 2 +-
 net/smc/smc_ib.h  | 1 +
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 3e16b887cfcf..ea0068f0173c 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -372,7 +372,8 @@ int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
 	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
 	dclc.hdr.version = SMC_CLC_V1;
 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
-	if (smc->conn.lgr && !smc->conn.lgr->is_smcd)
+	if ((!smc->conn.lgr || !smc->conn.lgr->is_smcd) &&
+	    smc_ib_is_valid_local_systemid())
 		memcpy(dclc.id_for_peer, local_systemid,
 		       sizeof(local_systemid));
 	dclc.peer_diagnosis = htonl(peer_diag_info);
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index e0592d337a94..3444de27fecd 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -166,7 +166,7 @@ static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
 	       sizeof(smcibdev->mac[ibport - 1]));
 }
 
-static bool smc_ib_is_valid_local_systemid(void)
+bool smc_ib_is_valid_local_systemid(void)
 {
 	return !is_zero_ether_addr(&local_systemid[2]);
 }
diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
index 255db87547d3..5c2b115d36da 100644
--- a/net/smc/smc_ib.h
+++ b/net/smc/smc_ib.h
@@ -84,4 +84,5 @@ void smc_ib_sync_sg_for_device(struct smc_ib_device *smcibdev,
 			       enum dma_data_direction data_direction);
 int smc_ib_determine_gid(struct smc_ib_device *smcibdev, u8 ibport,
 			 unsigned short vlan_id, u8 gid[], u8 *sgid_index);
+bool smc_ib_is_valid_local_systemid(void);
 #endif
-- 
2.25.1

Re: [PATCH net-next v2 0/2] net/smc: improve peer ID in CLC decline

[Karsten Graul]

Acked-by: Karsten Graul <kgraul@linux.ibm.com>


On 25/02/2020 22:41, Hans Wippel wrote:
> The following two patches improve the peer ID in CLC decline messages if
> RoCE devices are present in the host but no suitable device is found for
> a connection. The first patch reworks the peer ID initialization. The
> second patch contains the actual changes of the CLC decline messages.
> 
> Changes v1 -> v2:
> * make smc_ib_is_valid_local_systemid() static in first patch
> * changed if in smc_clc_send_decline() to remove curly braces
> 
> Changes RFC -> v1:
> * split the patch into two parts
> * removed zero assignment to global variable (thanks Leon)
> 
> Thanks to Leon Romanovsky and Karsten Graul for the feedback!
> 
> Hans Wippel (2):
>   net/smc: rework peer ID handling
>   net/smc: improve peer ID in CLC decline for SMC-R
> 
>  net/smc/smc_clc.c |  3 ++-
>  net/smc/smc_ib.c  | 19 ++++++++++++-------
>  net/smc/smc_ib.h  |  1 +
>  3 files changed, 15 insertions(+), 8 deletions(-)
> 

-- 
Karsten

(I'm a dude)

Re: [PATCH net-next v2 0/2] net/smc: improve peer ID in CLC decline

[David Miller]

From: Hans Wippel <ndev@hwipl.net>
Date: Tue, 25 Feb 2020 22:41:20 +0100

> The following two patches improve the peer ID in CLC decline messages if
> RoCE devices are present in the host but no suitable device is found for
> a connection. The first patch reworks the peer ID initialization. The
> second patch contains the actual changes of the CLC decline messages.
> 
> Changes v1 -> v2:
> * make smc_ib_is_valid_local_systemid() static in first patch
> * changed if in smc_clc_send_decline() to remove curly braces
> 
> Changes RFC -> v1:
> * split the patch into two parts
> * removed zero assignment to global variable (thanks Leon)
> 
> Thanks to Leon Romanovsky and Karsten Graul for the feedback!

Series applied, thank you.