This is a note to let you know that I've just added the patch titled
net/smc: {at|de}tach sndbuf to peer DMB if supported
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-smc-at-de-tach-sndbuf-to-peer-dmb-if-supported.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 48daf19b52680d489b64e6e66725242ce02df0af
Author: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Date: Sun Apr 28 14:07:36 2024 +0800
net/smc: {at|de}tach sndbuf to peer DMB if supported
[ Upstream commit ae2be35cbed2c8385e890147ea321a3fcc3ca5fa ]
If the device used by SMC-D supports merging local sndbuf to peer DMB,
then create sndbuf descriptor and attach it to peer DMB once peer
token is obtained, and detach and free the sndbuf descriptor when the
connection is freed.
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Reviewed-by: Wenjia Zhang <wenjia@xxxxxxxxxxxxx>
Reviewed-and-tested-by: Jan Karcher <jaka@xxxxxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Stable-dep-of: 0541db8ee32c ("net/smc: initialize close_work early to avoid warning")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f3ed53ae849d3..c4b30ea4b6ca0 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1418,6 +1418,14 @@ static int smc_connect_ism(struct smc_sock *smc,
}
smc_conn_save_peer_info(smc, aclc);
+
+ if (smc_ism_support_dmb_nocopy(smc->conn.lgr->smcd)) {
+ rc = smcd_buf_attach(smc);
+ if (rc) {
+ rc = SMC_CLC_DECL_MEM; /* try to fallback */
+ goto connect_abort;
+ }
+ }
smc_close_init(smc);
smc_rx_init(smc);
smc_tx_init(smc);
@@ -2522,6 +2530,14 @@ static void smc_listen_work(struct work_struct *work)
mutex_unlock(&smc_server_lgr_pending);
}
smc_conn_save_peer_info(new_smc, cclc);
+
+ if (ini->is_smcd &&
+ smc_ism_support_dmb_nocopy(new_smc->conn.lgr->smcd)) {
+ rc = smcd_buf_attach(new_smc);
+ if (rc)
+ goto out_decl;
+ }
+
smc_listen_out_connected(new_smc);
SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk), ini);
goto out_free;
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 605cdff671d65..0eeb0d4353446 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1143,6 +1143,20 @@ static void smcr_buf_unuse(struct smc_buf_desc *buf_desc, bool is_rmb,
}
}
+static void smcd_buf_detach(struct smc_connection *conn)
+{
+ struct smcd_dev *smcd = conn->lgr->smcd;
+ u64 peer_token = conn->peer_token;
+
+ if (!conn->sndbuf_desc)
+ return;
+
+ smc_ism_detach_dmb(smcd, peer_token);
+
+ kfree(conn->sndbuf_desc);
+ conn->sndbuf_desc = NULL;
+}
+
static void smc_buf_unuse(struct smc_connection *conn,
struct smc_link_group *lgr)
{
@@ -1186,6 +1200,8 @@ void smc_conn_free(struct smc_connection *conn)
if (lgr->is_smcd) {
if (!list_empty(&lgr->list))
smc_ism_unset_conn(conn);
+ if (smc_ism_support_dmb_nocopy(lgr->smcd))
+ smcd_buf_detach(conn);
tasklet_kill(&conn->rx_tsklet);
} else {
smc_cdc_wait_pend_tx_wr(conn);
@@ -1439,6 +1455,8 @@ static void smc_conn_kill(struct smc_connection *conn, bool soft)
smc_sk_wake_ups(smc);
if (conn->lgr->is_smcd) {
smc_ism_unset_conn(conn);
+ if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))
+ smcd_buf_detach(conn);
if (soft)
tasklet_kill(&conn->rx_tsklet);
else
@@ -2453,12 +2471,18 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
int rc;
/* create send buffer */
+ if (is_smcd &&
+ smc_ism_support_dmb_nocopy(smc->conn.lgr->smcd))
+ goto create_rmb;
+
rc = __smc_buf_create(smc, is_smcd, false);
if (rc)
return rc;
+
+create_rmb:
/* create rmb */
rc = __smc_buf_create(smc, is_smcd, true);
- if (rc) {
+ if (rc && smc->conn.sndbuf_desc) {
down_write(&smc->conn.lgr->sndbufs_lock);
list_del(&smc->conn.sndbuf_desc->list);
up_write(&smc->conn.lgr->sndbufs_lock);
@@ -2468,6 +2492,41 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
return rc;
}
+int smcd_buf_attach(struct smc_sock *smc)
+{
+ struct smc_connection *conn = &smc->conn;
+ struct smcd_dev *smcd = conn->lgr->smcd;
+ u64 peer_token = conn->peer_token;
+ struct smc_buf_desc *buf_desc;
+ int rc;
+
+ buf_desc = kzalloc(sizeof(*buf_desc), GFP_KERNEL);
+ if (!buf_desc)
+ return -ENOMEM;
+
+ /* The ghost sndbuf_desc describes the same memory region as
+ * peer RMB. Its lifecycle is consistent with the connection's
+ * and it will be freed with the connections instead of the
+ * link group.
+ */
+ rc = smc_ism_attach_dmb(smcd, peer_token, buf_desc);
+ if (rc)
+ goto free;
+
+ smc->sk.sk_sndbuf = buf_desc->len;
+ buf_desc->cpu_addr =
+ (u8 *)buf_desc->cpu_addr + sizeof(struct smcd_cdc_msg);
+ buf_desc->len -= sizeof(struct smcd_cdc_msg);
+ conn->sndbuf_desc = buf_desc;
+ conn->sndbuf_desc->used = 1;
+ atomic_set(&conn->sndbuf_space, conn->sndbuf_desc->len);
+ return 0;
+
+free:
+ kfree(buf_desc);
+ return rc;
+}
+
static inline int smc_rmb_reserve_rtoken_idx(struct smc_link_group *lgr)
{
int i;
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 670f8359da558..de001f4b46c7d 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -556,6 +556,7 @@ void smc_smcd_terminate(struct smcd_dev *dev, struct smcd_gid *peer_gid,
void smc_smcd_terminate_all(struct smcd_dev *dev);
void smc_smcr_terminate_all(struct smc_ib_device *smcibdev);
int smc_buf_create(struct smc_sock *smc, bool is_smcd);
+int smcd_buf_attach(struct smc_sock *smc);
int smc_uncompress_bufsize(u8 compressed);
int smc_rmb_rtoken_handling(struct smc_connection *conn, struct smc_link *link,
struct smc_clc_msg_accept_confirm *clc);
