Subject: [RFC PATCH net-next v5 03/11] net/smc: implement ID-related operations of loopback-ism

From: Wen Gu <[email-masked]>
Date: Sun, 24 Mar 2024 21:55:14 +0800

This implements operations related to IDs for the loopback-ism device.
loopback-ism uses an Extended GID that is a 128-bit GID instead of the
existing ISM 64-bit GID, and uses the CHID defined with the reserved
value 0xFFFF.

Signed-off-by: Wen Gu <[email-masked]>
---
 net/smc/smc_loopback.c | 62 ++++++++++++++++++++++++++++++++++++++----
 net/smc/smc_loopback.h |  3 ++
 2 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
index 3990f689ae79..3eb623e030eb 100644
--- a/net/smc/smc_loopback.c
+++ b/net/smc/smc_loopback.c
@@ -19,11 +19,62 @@
 #include "smc_loopback.h"
 
 #if IS_ENABLED(CONFIG_SMC_LO)
+#define SMC_LO_V2_CAPABLE	0x1 /* loopback-ism acts as ISMv2 */
+
 static const char smc_lo_dev_name[] = "loopback-ism";
 static struct smc_lo_dev *lo_dev;
 
+static void smc_lo_generate_ids(struct smc_lo_dev *ldev)
+{
+	struct smcd_gid *lgid = &ldev->local_gid;
+	uuid_t uuid;
+
+	uuid_gen(&uuid);
+	memcpy(&lgid->gid, &uuid, sizeof(lgid->gid));
+	memcpy(&lgid->gid_ext, (u8 *)&uuid + sizeof(lgid->gid),
+	       sizeof(lgid->gid_ext));
+
+	ldev->chid = SMC_LO_RESERVED_CHID;
+}
+
+static int smc_lo_query_rgid(struct smcd_dev *smcd, struct smcd_gid *rgid,
+			     u32 vid_valid, u32 vid)
+{
+	struct smc_lo_dev *ldev = smcd->priv;
+
+	/* rgid should be the same as lgid */
+	if (!ldev || rgid->gid != ldev->local_gid.gid ||
+	    rgid->gid_ext != ldev->local_gid.gid_ext)
+		return -ENETUNREACH;
+	return 0;
+}
+
+static int smc_lo_supports_v2(void)
+{
+	return SMC_LO_V2_CAPABLE;
+}
+
+static void smc_lo_get_local_gid(struct smcd_dev *smcd,
+				 struct smcd_gid *smcd_gid)
+{
+	struct smc_lo_dev *ldev = smcd->priv;
+
+	smcd_gid->gid = ldev->local_gid.gid;
+	smcd_gid->gid_ext = ldev->local_gid.gid_ext;
+}
+
+static u16 smc_lo_get_chid(struct smcd_dev *smcd)
+{
+	return ((struct smc_lo_dev *)smcd->priv)->chid;
+}
+
+static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
+{
+	return &((struct smc_lo_dev *)smcd->priv)->dev;
+}
+
 static const struct smcd_ops lo_ops = {
-	.query_remote_gid	= NULL,
+	.query_remote_gid = smc_lo_query_rgid,
 	.register_dmb		= NULL,
 	.unregister_dmb		= NULL,
 	.add_vlan_id		= NULL,
@@ -32,10 +83,10 @@ static const struct smcd_ops lo_ops = {
 	.reset_vlan_required	= NULL,
 	.signal_event		= NULL,
 	.move_data		= NULL,
-	.supports_v2		= NULL,
-	.get_local_gid		= NULL,
-	.get_chid		= NULL,
-	.get_dev		= NULL,
+	.supports_v2 = smc_lo_supports_v2,
+	.get_local_gid = smc_lo_get_local_gid,
+	.get_chid = smc_lo_get_chid,
+	.get_dev = smc_lo_get_dev,
 };
 
 static struct smcd_dev *smcd_lo_alloc_dev(const struct smcd_ops *ops,
@@ -95,6 +146,7 @@ static void smcd_lo_unregister_dev(struct smc_lo_dev *ldev)
 
 static int smc_lo_dev_init(struct smc_lo_dev *ldev)
 {
+	smc_lo_generate_ids(ldev);
 	return smcd_lo_register_dev(ldev);
 }
 
diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
index 77980650b2bd..11868e5ac732 100644
--- a/net/smc/smc_loopback.h
+++ b/net/smc/smc_loopback.h
@@ -20,10 +20,13 @@
 
 #if IS_ENABLED(CONFIG_SMC_LO)
 #define SMC_LO_MAX_DMBS		5000
+#define SMC_LO_RESERVED_CHID	0xFFFF
 
 struct smc_lo_dev {
 	struct smcd_dev *smcd;
 	struct device dev;
+	u16 chid;
+	struct smcd_gid local_gid;
 };
 #endif
 
-- 
2.32.0.3.g01195cf9f