Re: [PATCH net-next v3 12/18] net/smc: implement DMB-related operations of loopback

From: Wenjia Zhang
Date: Thu Sep 21 2023 - 19:37:18 EST



On 21.09.23 15:19, Wen Gu wrote:
This patch implements DMB registration, unregistration and data move
operations of SMC-D loopback.

Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
---
net/smc/smc_cdc.c | 6 +++
net/smc/smc_cdc.h | 1 +
net/smc/smc_loopback.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++--
net/smc/smc_loopback.h | 13 +++++
4 files changed, 145 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index 89105e9..2641800 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -411,6 +411,12 @@ static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
{
struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
+
+ smcd_cdc_rx_handler(conn);
+}
+
+void smcd_cdc_rx_handler(struct smc_connection *conn)
+{
struct smcd_cdc_msg *data_cdc;
struct smcd_cdc_msg cdc;
struct smc_sock *smc;
diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
index 696cc11..11559d4 100644
--- a/net/smc/smc_cdc.h
+++ b/net/smc/smc_cdc.h
@@ -301,5 +301,6 @@ int smcr_cdc_msg_send_validation(struct smc_connection *conn,
struct smc_wr_buf *wr_buf);
int smc_cdc_init(void) __init;
void smcd_cdc_rx_init(struct smc_connection *conn);
+void smcd_cdc_rx_handler(struct smc_connection *conn);
#endif /* SMC_CDC_H */
diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
index 9034ebd..cfbcabf 100644
--- a/net/smc/smc_loopback.c
+++ b/net/smc/smc_loopback.c
@@ -16,6 +16,7 @@
#include <linux/smc.h>
#include <net/smc.h>
+#include "smc_cdc.h"
#include "smc_ism.h"
#include "smc_loopback.h"
@@ -74,6 +75,93 @@ static int smc_lo_query_rgid(struct smcd_dev *smcd, struct smcd_gid *rgid,
return 0;
}
+static int smc_lo_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
+ void *client_priv)
+{
+ struct smc_lo_dmb_node *dmb_node, *tmp_node;
+ struct smc_lo_dev *ldev = smcd->priv;
+ int sba_idx, rc;
+
+ /* check space for new dmb */
+ for_each_clear_bit(sba_idx, ldev->sba_idx_mask, SMC_LODEV_MAX_DMBS) {
+ if (!test_and_set_bit(sba_idx, ldev->sba_idx_mask))
+ break;
+ }
+ if (sba_idx == SMC_LODEV_MAX_DMBS)
+ return -ENOSPC;
+
+ dmb_node = kzalloc(sizeof(*dmb_node), GFP_KERNEL);
+ if (!dmb_node) {
+ rc = -ENOMEM;
+ goto err_bit;
+ }
+
+ dmb_node->sba_idx = sba_idx;
+ dmb_node->cpu_addr = kzalloc(dmb->dmb_len, GFP_KERNEL |
+ __GFP_NOWARN | __GFP_NORETRY |
+ __GFP_NOMEMALLOC);
kzalloc()/kmalloc() allocates physically contigueous memory. Are you sure it is suitable for allocating the dmb?

+ if (!dmb_node->cpu_addr) {
+ rc = -ENOMEM;
+ goto err_node;
+ }
+ dmb_node->len = dmb->dmb_len;
+ dmb_node->dma_addr = (dma_addr_t)dmb_node->cpu_addr;
+
+again:
+ /* add new dmb into hash table */
+ get_random_bytes(&dmb_node->token, sizeof(dmb_node->token));
+ write_lock(&ldev->dmb_ht_lock);
+ hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_node->token) {
+ if (tmp_node->token == dmb_node->token) {
+ write_unlock(&ldev->dmb_ht_lock);
+ goto again;
+ }
+ }
+ hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);
+ write_unlock(&ldev->dmb_ht_lock);
+
+ dmb->sba_idx = dmb_node->sba_idx;
+ dmb->dmb_tok = dmb_node->token;
+ dmb->cpu_addr = dmb_node->cpu_addr;
+ dmb->dma_addr = dmb_node->dma_addr;
+ dmb->dmb_len = dmb_node->len;
+
+ return 0;
+
+err_node:
+ kfree(dmb_node);
+err_bit:
+ clear_bit(sba_idx, ldev->sba_idx_mask);
+ return rc;
+}
+
+static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
+{
+ struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
+ struct smc_lo_dev *ldev = smcd->priv;
+
+ /* remove dmb from hash table */
+ write_lock(&ldev->dmb_ht_lock);
+ hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
+ if (tmp_node->token == dmb->dmb_tok) {
+ dmb_node = tmp_node;
+ break;
+ }
+ }
+ if (!dmb_node) {
+ write_unlock(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ hash_del(&dmb_node->list);
+ write_unlock(&ldev->dmb_ht_lock);
+
+ clear_bit(dmb_node->sba_idx, ldev->sba_idx_mask);
+ kfree(dmb_node->cpu_addr);
+ kfree(dmb_node);
+
+ return 0;
+}
+
static int smc_lo_add_vlan_id(struct smcd_dev *smcd, u64 vlan_id)
{
return -EOPNOTSUPP;
@@ -100,6 +188,38 @@ static int smc_lo_signal_event(struct smcd_dev *dev, struct smcd_gid *rgid,
return 0;
}
+static int smc_lo_move_data(struct smcd_dev *smcd, u64 dmb_tok, unsigned int idx,
+ bool sf, unsigned int offset, void *data,
+ unsigned int size)
+{
+ struct smc_lo_dmb_node *rmb_node = NULL, *tmp_node;
+ struct smc_lo_dev *ldev = smcd->priv;
+
+ read_lock(&ldev->dmb_ht_lock);
+ hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_tok) {
+ if (tmp_node->token == dmb_tok) {
+ rmb_node = tmp_node;
+ break;
+ }
+ }
+ if (!rmb_node) {
+ read_unlock(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ read_unlock(&ldev->dmb_ht_lock);
+
+ memcpy((char *)rmb_node->cpu_addr + offset, data, size);
+
+ if (sf) {
+ struct smc_connection *conn =
+ smcd->conn[rmb_node->sba_idx];
+
+ if (conn && !conn->killed)
+ smcd_cdc_rx_handler(conn);
+ }
+ return 0;
+}
+
static int smc_lo_supports_v2(void)
{
return SMC_LO_SUPPORTS_V2;
@@ -131,14 +251,14 @@ static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
static const struct smcd_ops lo_ops = {
.query_remote_gid = smc_lo_query_rgid,
- .register_dmb = NULL,
- .unregister_dmb = NULL,
+ .register_dmb = smc_lo_register_dmb,
+ .unregister_dmb = smc_lo_unregister_dmb,
.add_vlan_id = smc_lo_add_vlan_id,
.del_vlan_id = smc_lo_del_vlan_id,
.set_vlan_required = smc_lo_set_vlan_required,
.reset_vlan_required = smc_lo_reset_vlan_required,
.signal_event = smc_lo_signal_event,
- .move_data = NULL,
+ .move_data = smc_lo_move_data,
.supports_v2 = smc_lo_supports_v2,
.get_system_eid = smc_lo_get_system_eid,
.get_local_gid = smc_lo_get_local_gid,
@@ -212,6 +332,8 @@ static void smc_lo_dev_release(struct device *dev)
static int smc_lo_dev_init(struct smc_lo_dev *ldev)
{
smc_lo_generate_id(ldev);
+ rwlock_init(&ldev->dmb_ht_lock);
+ hash_init(ldev->dmb_ht);
return smcd_lo_register_dev(ldev);
}
diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
index 2156f22..943424f 100644
--- a/net/smc/smc_loopback.h
+++ b/net/smc/smc_loopback.h
@@ -20,12 +20,25 @@
#define SMC_LO_CHID 0xFFFF
#define SMC_LODEV_MAX_DMBS 5000
+#define SMC_LODEV_DMBS_HASH_BITS 12
+
+struct smc_lo_dmb_node {
+ struct hlist_node list;
+ u64 token;
+ u32 len;
+ u32 sba_idx;
+ void *cpu_addr;
+ dma_addr_t dma_addr;
+};
struct smc_lo_dev {
struct smcd_dev *smcd;
struct device dev;
u16 chid;
struct smcd_gid local_gid;
+ DECLARE_BITMAP(sba_idx_mask, SMC_LODEV_MAX_DMBS);
+ rwlock_t dmb_ht_lock;
+ DECLARE_HASHTABLE(dmb_ht, SMC_LODEV_DMBS_HASH_BITS);
};
int smc_loopback_init(void);