[PATCH net 00/10] net/smc: fixes 2020-07-16

[PATCH net 00/10] net/smc: fixes 2020-07-16

[Karsten Graul]

Please apply the following patch series for smc to netdev's net tree.

The patches address problems caused by late or unexpected link layer
control packets, dma sync calls for unmapped memory, freed buffers
that are not removed from the buffer list and a possible null pointer
access that results in a crash.

Thanks,
Karsten

Karsten Graul (10):
  net/smc: handle unexpected response types for confirm link
  net/smc: clear link during SMC client link down processing
  net/smc: fix link lookup for new rdma connections
  net/smc: protect smc ib device initialization
  net/smc: drop out-of-flow llc response messages
  net/smc: move add link processing for new device into llc layer
  net/smc: fix handling of delete link requests
  net/smc: do not call dma sync for unmapped memory
  net/smc: remove freed buffer from list
  net/smc: fix restoring of fallback changes

 net/smc/af_smc.c   |  12 +++--
 net/smc/smc_core.c | 105 ++++++++-----------------------------
 net/smc/smc_core.h |   5 ++
 net/smc/smc_ib.c   |  16 ++++--
 net/smc/smc_ib.h   |   1 +
 net/smc/smc_llc.c  | 127 ++++++++++++++++++++++++++++++---------------
 net/smc/smc_llc.h  |   2 +-
 7 files changed, 135 insertions(+), 133 deletions(-)

-- 
2.17.1

[PATCH net 01/10] net/smc: handle unexpected response types for confirm link

[Karsten Graul]

A delete link could arrive during confirm link processing. Handle this
situation directly in smc_llc_srv_conf_link() rather than using the
logic in smc_llc_wait() to avoid the unexpected message handling there.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 1551c95b6124 ("net/smc: final part of add link processing as SMC server")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_llc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index c1a038689c63..58f4da2e0cc7 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -1051,12 +1051,14 @@ static int smc_llc_srv_conf_link(struct smc_link *link,
 	if (rc)
 		return -ENOLINK;
 	/* receive CONFIRM LINK response over the RoCE fabric */
-	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_FIRST_TIME,
-			      SMC_LLC_CONFIRM_LINK);
-	if (!qentry) {
+	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_FIRST_TIME, 0);
+	if (!qentry ||
+	    qentry->msg.raw.hdr.common.type != SMC_LLC_CONFIRM_LINK) {
 		/* send DELETE LINK */
 		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
 					 false, SMC_LLC_DEL_LOST_PATH);
+		if (qentry)
+			smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
 		return -ENOLINK;
 	}
 	smc_llc_save_peer_uid(qentry);
-- 
2.17.1

[PATCH net 02/10] net/smc: clear link during SMC client link down processing

[Karsten Graul]

In a link-down condition we notify the SMC server and expect that the
server will finally trigger the link clear processing on the client
side. This could fail when anything along this notification path goes
wrong. Clear the link as part of SMC client link-down processing to
prevent dangling links.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 541afa10c126 ("net/smc: add smcr_port_err() and smcr_link_down() processing")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index f69d205b3e11..e286b3c8c962 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1204,10 +1204,12 @@ static void smcr_link_down(struct smc_link *lnk)
 				SMC_LLC_WAIT_TIME);
 			mutex_lock(&lgr->llc_conf_mutex);
 		}
-		if (!list_empty(&lgr->list))
+		if (!list_empty(&lgr->list)) {
 			smc_llc_send_delete_link(to_lnk, del_link_id,
 						 SMC_LLC_REQ, true,
 						 SMC_LLC_DEL_LOST_PATH);
+			smcr_link_clear(lnk, true);
+		}
 		wake_up(&lgr->llc_flow_waiter);	/* wake up next waiter */
 	}
 }
-- 
2.17.1

[PATCH net 03/10] net/smc: fix link lookup for new rdma connections

[Karsten Graul]

For new rdma connections the SMC server assigns the link and sends the
link data in the clc accept message. To match the correct link use not
only the qp_num but also the gid and the mac of the links. If there are
equal qp_nums for different links the wrong link would be chosen.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 0fb0b02bd6fd ("net/smc: adapt SMC client code to use the LLC flow")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/af_smc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 903321543838..f80591567a3d 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -632,7 +632,9 @@ static int smc_connect_rdma(struct smc_sock *smc,
 		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 			struct smc_link *l = &smc->conn.lgr->lnk[i];
 
-			if (l->peer_qpn == ntoh24(aclc->qpn)) {
+			if (l->peer_qpn == ntoh24(aclc->qpn) &&
+			    !memcmp(l->peer_gid, &aclc->lcl.gid, SMC_GID_SIZE) &&
+			    !memcmp(l->peer_mac, &aclc->lcl.mac, sizeof(l->peer_mac))) {
 				link = l;
 				break;
 			}
-- 
2.17.1

[PATCH net 04/10] net/smc: protect smc ib device initialization

[Karsten Graul]

Before an smc ib device is used the first time for an smc link it is
lazily initialized. When there are 2 active link groups and a new ib
device is brought online then it might happen that 2 link creations run
in parallel and enter smc_ib_setup_per_ibdev(). Both allocate new send
and receive completion queues on the device, but only one set of them
keeps assigned and the other leaks.
Fix that by protecting the critical code using a mutex.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: f3c1deddb21c ("net/smc: separate function for link initialization")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_ib.c | 16 +++++++++++++---
 net/smc/smc_ib.h |  1 +
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 7637fdebbb78..1c314dbdc7fa 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -506,6 +506,10 @@ long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
 	int cqe_size_order, smc_order;
 	long rc;
 
+	mutex_lock(&smcibdev->mutex);
+	rc = 0;
+	if (smcibdev->initialized)
+		goto out;
 	/* the calculated number of cq entries fits to mlx5 cq allocation */
 	cqe_size_order = cache_line_size() == 128 ? 7 : 6;
 	smc_order = MAX_ORDER - cqe_size_order - 1;
@@ -517,7 +521,7 @@ long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
 	rc = PTR_ERR_OR_ZERO(smcibdev->roce_cq_send);
 	if (IS_ERR(smcibdev->roce_cq_send)) {
 		smcibdev->roce_cq_send = NULL;
-		return rc;
+		goto out;
 	}
 	smcibdev->roce_cq_recv = ib_create_cq(smcibdev->ibdev,
 					      smc_wr_rx_cq_handler, NULL,
@@ -529,21 +533,26 @@ long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
 	}
 	smc_wr_add_dev(smcibdev);
 	smcibdev->initialized = 1;
-	return rc;
+	goto out;
 
 err:
 	ib_destroy_cq(smcibdev->roce_cq_send);
+out:
+	mutex_unlock(&smcibdev->mutex);
 	return rc;
 }
 
 static void smc_ib_cleanup_per_ibdev(struct smc_ib_device *smcibdev)
 {
+	mutex_lock(&smcibdev->mutex);
 	if (!smcibdev->initialized)
-		return;
+		goto out;
 	smcibdev->initialized = 0;
 	ib_destroy_cq(smcibdev->roce_cq_recv);
 	ib_destroy_cq(smcibdev->roce_cq_send);
 	smc_wr_remove_dev(smcibdev);
+out:
+	mutex_unlock(&smcibdev->mutex);
 }
 
 static struct ib_client smc_ib_client;
@@ -566,6 +575,7 @@ static int smc_ib_add_dev(struct ib_device *ibdev)
 	INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
 	atomic_set(&smcibdev->lnk_cnt, 0);
 	init_waitqueue_head(&smcibdev->lnks_deleted);
+	mutex_init(&smcibdev->mutex);
 	mutex_lock(&smc_ib_devices.mutex);
 	list_add_tail(&smcibdev->list, &smc_ib_devices.list);
 	mutex_unlock(&smc_ib_devices.mutex);
diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
index ae6776e1e726..afbb76622f03 100644
--- a/net/smc/smc_ib.h
+++ b/net/smc/smc_ib.h
@@ -52,6 +52,7 @@ struct smc_ib_device {				/* ib-device infos for smc */
 	DECLARE_BITMAP(ports_going_away, SMC_MAX_PORTS);
 	atomic_t		lnk_cnt;	/* number of links on ibdev */
 	wait_queue_head_t	lnks_deleted;	/* wait 4 removal of all links*/
+	struct mutex		mutex;		/* protects smc ib device */
 };
 
 struct smc_buf_desc;
-- 
2.17.1

Re: [PATCH net 04/10] net/smc: protect smc ib device initialization

[David Miller]

From: Karsten Graul <kgraul@linux.ibm.com>
Date: Thu, 16 Jul 2020 17:37:40 +0200

> Fix that by protecting the critical code using a mutex.
 ...
> @@ -52,6 +52,7 @@ struct smc_ib_device {				/* ib-device infos for smc */
>  	DECLARE_BITMAP(ports_going_away, SMC_MAX_PORTS);
>  	atomic_t		lnk_cnt;	/* number of links on ibdev */
>  	wait_queue_head_t	lnks_deleted;	/* wait 4 removal of all links*/
> +	struct mutex		mutex;		/* protects smc ib device */
>  };

So which is it?  Does the mutex protect the entire contents of the
smc ib device struct, as stated in the comment?  Or does it only
synchronize object creation?

One of them is obviously wrong, so please correct that.

[PATCH net 05/10] net/smc: drop out-of-flow llc response messages

[Karsten Graul]

To be save from unexpected or late llc response messages check if the
arrived message fits to the current flow type and drop out-of-flow
messages. And drop it when there is already a response assigned to
the flow.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: ef79d439cd12 ("net/smc: process llc responses in tasklet context")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_llc.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 58f4da2e0cc7..78704f03e72a 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -1587,6 +1587,8 @@ static void smc_llc_event_work(struct work_struct *work)
 static void smc_llc_rx_response(struct smc_link *link,
 				struct smc_llc_qentry *qentry)
 {
+	enum smc_llc_flowtype flowtype = link->lgr->llc_flow_lcl.type;
+	struct smc_llc_flow *flow = &link->lgr->llc_flow_lcl;
 	u8 llc_type = qentry->msg.raw.hdr.common.type;
 
 	switch (llc_type) {
@@ -1595,15 +1597,20 @@ static void smc_llc_rx_response(struct smc_link *link,
 			complete(&link->llc_testlink_resp);
 		break;
 	case SMC_LLC_ADD_LINK:
-	case SMC_LLC_DELETE_LINK:
-	case SMC_LLC_CONFIRM_LINK:
 	case SMC_LLC_ADD_LINK_CONT:
+	case SMC_LLC_CONFIRM_LINK:
+		if (flowtype != SMC_LLC_FLOW_ADD_LINK || flow->qentry)
+			break;	/* drop out-of-flow response */
+		goto assign;
+	case SMC_LLC_DELETE_LINK:
+		if (flowtype != SMC_LLC_FLOW_DEL_LINK || flow->qentry)
+			break;	/* drop out-of-flow response */
+		goto assign;
 	case SMC_LLC_CONFIRM_RKEY:
 	case SMC_LLC_DELETE_RKEY:
-		/* assign responses to the local flow, we requested them */
-		smc_llc_flow_qentry_set(&link->lgr->llc_flow_lcl, qentry);
-		wake_up(&link->lgr->llc_msg_waiter);
-		return;
+		if (flowtype != SMC_LLC_FLOW_RKEY || flow->qentry)
+			break;	/* drop out-of-flow response */
+		goto assign;
 	case SMC_LLC_CONFIRM_RKEY_CONT:
 		/* not used because max links is 3 */
 		break;
@@ -1612,6 +1619,11 @@ static void smc_llc_rx_response(struct smc_link *link,
 		break;
 	}
 	kfree(qentry);
+	return;
+assign:
+	/* assign responses to the local flow, we requested them */
+	smc_llc_flow_qentry_set(&link->lgr->llc_flow_lcl, qentry);
+	wake_up(&link->lgr->llc_msg_waiter);
 }
 
 static void smc_llc_enqueue(struct smc_link *link, union smc_llc_msg *llc)
-- 
2.17.1

[PATCH net 06/10] net/smc: move add link processing for new device into llc layer

[Karsten Graul]

When a new ib device is up smc will send an add link invitation to the
peer if needed. This is currently done with rudimentary flow control.
Under high workload these add link invitations can disturb other llc
flows because they arrive unexpected. Fix this by integrating the
invitations into the normal llc event flow and handle them as a flow.
While at it, check for already assigned requests in the flow before
the new add link request is assigned.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 1f90a05d9ff9 ("net/smc: add smcr_port_add() and smcr_link_up() processing")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_core.c | 80 ++++------------------------------------------
 net/smc/smc_llc.c  | 56 ++++++++++++++++++++++++++++----
 net/smc/smc_llc.h  |  2 +-
 3 files changed, 58 insertions(+), 80 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index e286b3c8c962..2e965de7412d 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -45,18 +45,10 @@ static struct smc_lgr_list smc_lgr_list = {	/* established link groups */
 static atomic_t lgr_cnt = ATOMIC_INIT(0); /* number of existing link groups */
 static DECLARE_WAIT_QUEUE_HEAD(lgrs_deleted);
 
-struct smc_ib_up_work {
-	struct work_struct	work;
-	struct smc_link_group	*lgr;
-	struct smc_ib_device	*smcibdev;
-	u8			ibport;
-};
-
 static void smc_buf_free(struct smc_link_group *lgr, bool is_rmb,
 			 struct smc_buf_desc *buf_desc);
 static void __smc_lgr_terminate(struct smc_link_group *lgr, bool soft);
 
-static void smc_link_up_work(struct work_struct *work);
 static void smc_link_down_work(struct work_struct *work);
 
 /* return head of link group list and its lock for a given link group */
@@ -1106,67 +1098,23 @@ static void smc_conn_abort_work(struct work_struct *work)
 	sock_put(&smc->sk); /* sock_hold done by schedulers of abort_work */
 }
 
-/* link is up - establish alternate link if applicable */
-static void smcr_link_up(struct smc_link_group *lgr,
-			 struct smc_ib_device *smcibdev, u8 ibport)
-{
-	struct smc_link *link = NULL;
-
-	if (list_empty(&lgr->list) ||
-	    lgr->type == SMC_LGR_SYMMETRIC ||
-	    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
-		return;
-
-	if (lgr->role == SMC_SERV) {
-		/* trigger local add link processing */
-		link = smc_llc_usable_link(lgr);
-		if (!link)
-			return;
-		smc_llc_srv_add_link_local(link);
-	} else {
-		/* invite server to start add link processing */
-		u8 gid[SMC_GID_SIZE];
-
-		if (smc_ib_determine_gid(smcibdev, ibport, lgr->vlan_id, gid,
-					 NULL))
-			return;
-		if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
-			/* some other llc task is ongoing */
-			wait_event_timeout(lgr->llc_flow_waiter,
-				(list_empty(&lgr->list) ||
-				 lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE),
-				SMC_LLC_WAIT_TIME);
-		}
-		/* lgr or device no longer active? */
-		if (!list_empty(&lgr->list) &&
-		    smc_ib_port_active(smcibdev, ibport))
-			link = smc_llc_usable_link(lgr);
-		if (link)
-			smc_llc_send_add_link(link, smcibdev->mac[ibport - 1],
-					      gid, NULL, SMC_LLC_REQ);
-		wake_up(&lgr->llc_flow_waiter);	/* wake up next waiter */
-	}
-}
-
 void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport)
 {
-	struct smc_ib_up_work *ib_work;
 	struct smc_link_group *lgr, *n;
 
 	list_for_each_entry_safe(lgr, n, &smc_lgr_list.list, list) {
+		struct smc_link *link;
+
 		if (strncmp(smcibdev->pnetid[ibport - 1], lgr->pnet_id,
 			    SMC_MAX_PNETID_LEN) ||
 		    lgr->type == SMC_LGR_SYMMETRIC ||
 		    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
 			continue;
-		ib_work = kmalloc(sizeof(*ib_work), GFP_KERNEL);
-		if (!ib_work)
-			continue;
-		INIT_WORK(&ib_work->work, smc_link_up_work);
-		ib_work->lgr = lgr;
-		ib_work->smcibdev = smcibdev;
-		ib_work->ibport = ibport;
-		schedule_work(&ib_work->work);
+
+		/* trigger local add link processing */
+		link = smc_llc_usable_link(lgr);
+		if (link)
+			smc_llc_add_link_local(link);
 	}
 }
 
@@ -1249,20 +1197,6 @@ void smcr_port_err(struct smc_ib_device *smcibdev, u8 ibport)
 	}
 }
 
-static void smc_link_up_work(struct work_struct *work)
-{
-	struct smc_ib_up_work *ib_work = container_of(work,
-						      struct smc_ib_up_work,
-						      work);
-	struct smc_link_group *lgr = ib_work->lgr;
-
-	if (list_empty(&lgr->list))
-		goto out;
-	smcr_link_up(lgr, ib_work->smcibdev, ib_work->ibport);
-out:
-	kfree(ib_work);
-}
-
 static void smc_link_down_work(struct work_struct *work)
 {
 	struct smc_link *link = container_of(work, struct smc_link,
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 78704f03e72a..30da040ab5b6 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -895,6 +895,36 @@ int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
 	return rc;
 }
 
+/* as an SMC client, invite server to start the add_link processing */
+static void smc_llc_cli_add_link_invite(struct smc_link *link,
+					struct smc_llc_qentry *qentry)
+{
+	struct smc_link_group *lgr = smc_get_lgr(link);
+	struct smc_init_info ini;
+
+	if (lgr->type == SMC_LGR_SYMMETRIC ||
+	    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
+		goto out;
+
+	ini.vlan_id = lgr->vlan_id;
+	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
+	if (!ini.ib_dev)
+		goto out;
+
+	smc_llc_send_add_link(link, ini.ib_dev->mac[ini.ib_port - 1],
+			      ini.ib_gid, NULL, SMC_LLC_REQ);
+out:
+	kfree(qentry);
+}
+
+static bool smc_llc_is_local_add_link(union smc_llc_msg *llc)
+{
+	if (llc->raw.hdr.common.type == SMC_LLC_ADD_LINK &&
+	    !llc->add_link.qp_mtu && !llc->add_link.link_num)
+		return true;
+	return false;
+}
+
 static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
 {
 	struct smc_llc_qentry *qentry;
@@ -902,7 +932,10 @@ static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
 	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
 
 	mutex_lock(&lgr->llc_conf_mutex);
-	smc_llc_cli_add_link(qentry->link, qentry);
+	if (smc_llc_is_local_add_link(&qentry->msg))
+		smc_llc_cli_add_link_invite(qentry->link, qentry);
+	else
+		smc_llc_cli_add_link(qentry->link, qentry);
 	mutex_unlock(&lgr->llc_conf_mutex);
 }
 
@@ -1160,14 +1193,14 @@ static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
 	mutex_unlock(&lgr->llc_conf_mutex);
 }
 
-/* enqueue a local add_link req to trigger a new add_link flow, only as SERV */
-void smc_llc_srv_add_link_local(struct smc_link *link)
+/* enqueue a local add_link req to trigger a new add_link flow */
+void smc_llc_add_link_local(struct smc_link *link)
 {
 	struct smc_llc_msg_add_link add_llc = {0};
 
 	add_llc.hd.length = sizeof(add_llc);
 	add_llc.hd.common.type = SMC_LLC_ADD_LINK;
-	/* no dev and port needed, we as server ignore client data anyway */
+	/* no dev and port needed */
 	smc_llc_enqueue(link, (union smc_llc_msg *)&add_llc);
 }
 
@@ -1347,7 +1380,7 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)
 
 	if (lgr->type == SMC_LGR_SINGLE && !list_empty(&lgr->list)) {
 		/* trigger setup of asymm alt link */
-		smc_llc_srv_add_link_local(lnk);
+		smc_llc_add_link_local(lnk);
 	}
 out:
 	mutex_unlock(&lgr->llc_conf_mutex);
@@ -1476,7 +1509,18 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
 		if (list_empty(&lgr->list))
 			goto out;	/* lgr is terminating */
 		if (lgr->role == SMC_CLNT) {
-			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK) {
+			if (smc_llc_is_local_add_link(llc)) {
+				if (lgr->llc_flow_lcl.type ==
+				    SMC_LLC_FLOW_ADD_LINK)
+					break;	/* add_link in progress */
+				if (smc_llc_flow_start(&lgr->llc_flow_lcl,
+						       qentry)) {
+					schedule_work(&lgr->llc_add_link_work);
+				}
+				return;
+			}
+			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
+			    !lgr->llc_flow_lcl.qentry) {
 				/* a flow is waiting for this message */
 				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
 							qentry);
diff --git a/net/smc/smc_llc.h b/net/smc/smc_llc.h
index a5d2fe3eea61..cc00a2ec4e92 100644
--- a/net/smc/smc_llc.h
+++ b/net/smc/smc_llc.h
@@ -103,7 +103,7 @@ void smc_llc_send_link_delete_all(struct smc_link_group *lgr, bool ord,
 				  u32 rsn);
 int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry);
 int smc_llc_srv_add_link(struct smc_link *link);
-void smc_llc_srv_add_link_local(struct smc_link *link);
+void smc_llc_add_link_local(struct smc_link *link);
 int smc_llc_init(void) __init;
 
 #endif /* SMC_LLC_H */
-- 
2.17.1

[PATCH net 07/10] net/smc: fix handling of delete link requests

[Karsten Graul]

As smc client the delete link requests are assigned to the flow when
_any_ flow is active. This may break other flows that do not expect
delete link requests during their handling. Fix that by assigning the
request only when an add link flow is active. With that fix the code
for smc client and smc server is the same, so remove the separate
handling.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 9ec6bf19ec8b ("net/smc: llc_del_link_work and use the LLC flow for delete link")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_llc.c | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 30da040ab5b6..fa8cd57a9b32 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -1544,28 +1544,13 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
 		}
 		break;
 	case SMC_LLC_DELETE_LINK:
-		if (lgr->role == SMC_CLNT) {
-			/* server requests to delete this link, send response */
-			if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
-				/* DEL LINK REQ during ADD LINK SEQ */
-				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
-							qentry);
-				wake_up(&lgr->llc_msg_waiter);
-			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
-						      qentry)) {
-				schedule_work(&lgr->llc_del_link_work);
-			}
-		} else {
-			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
-			    !lgr->llc_flow_lcl.qentry) {
-				/* DEL LINK REQ during ADD LINK SEQ */
-				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
-							qentry);
-				wake_up(&lgr->llc_msg_waiter);
-			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
-						      qentry)) {
-				schedule_work(&lgr->llc_del_link_work);
-			}
+		if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
+		    !lgr->llc_flow_lcl.qentry) {
+			/* DEL LINK REQ during ADD LINK SEQ */
+			smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry);
+			wake_up(&lgr->llc_msg_waiter);
+		} else if (smc_llc_flow_start(&lgr->llc_flow_lcl, qentry)) {
+			schedule_work(&lgr->llc_del_link_work);
 		}
 		return;
 	case SMC_LLC_CONFIRM_RKEY:
-- 
2.17.1

[PATCH net 08/10] net/smc: do not call dma sync for unmapped memory

[Karsten Graul]

The dma related ...sync_sg... functions check the link state before the
dma function is actually called. But the check in smc_link_usable()
allows links in ACTIVATING state which are not yet mapped to dma memory.
Under high load it may happen that the sync_sg functions are called for
such a link which results in an debug output like
   DMA-API: mlx5_core 0002:00:00.0: device driver tries to sync
   DMA memory it has not allocated [device address=0x0000000103370000]
   [size=65536 bytes]
To fix that introduce a helper to check for the link state ACTIVE and
use it where appropriate. And move the link state update to ACTIVATING
to the end of smcr_link_init() when most initial setup is done.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: d854fcbfaeda ("net/smc: add new link state and related helpers")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/af_smc.c   |  2 +-
 net/smc/smc_core.c | 15 +++++++--------
 net/smc/smc_core.h |  5 +++++
 net/smc/smc_llc.c  | 10 +++++-----
 4 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f80591567a3d..d091509b5982 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -352,7 +352,7 @@ static int smcr_lgr_reg_rmbs(struct smc_link *link,
 	 */
 	mutex_lock(&lgr->llc_conf_mutex);
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		rc = smcr_link_reg_rmb(&lgr->lnk[i], rmb_desc);
 		if (rc)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 2e965de7412d..42ba227f3e97 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -318,7 +318,6 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 
 	get_device(&ini->ib_dev->ibdev->dev);
 	atomic_inc(&ini->ib_dev->lnk_cnt);
-	lnk->state = SMC_LNK_ACTIVATING;
 	lnk->link_id = smcr_next_link_id(lgr);
 	lnk->lgr = lgr;
 	lnk->link_idx = link_idx;
@@ -354,6 +353,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 	rc = smc_wr_create_link(lnk);
 	if (rc)
 		goto destroy_qp;
+	lnk->state = SMC_LNK_ACTIVATING;
 	return 0;
 
 destroy_qp:
@@ -542,8 +542,7 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr,
 	smc_wr_wakeup_tx_wait(from_lnk);
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE ||
-		    i == from_lnk->link_idx)
+		if (!smc_link_active(&lgr->lnk[i]) || i == from_lnk->link_idx)
 			continue;
 		if (is_dev_err && from_lnk->smcibdev == lgr->lnk[i].smcibdev &&
 		    from_lnk->ibport == lgr->lnk[i].ibport) {
@@ -1269,7 +1268,7 @@ static bool smcr_lgr_match(struct smc_link_group *lgr,
 		return false;
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		if ((lgr->role == SMC_SERV || lgr->lnk[i].peer_qpn == clcqpn) &&
 		    !memcmp(lgr->lnk[i].peer_gid, &lcl->gid, SMC_GID_SIZE) &&
@@ -1717,14 +1716,14 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
 
 void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_cpu(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
 
 void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_device(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
@@ -1736,7 +1735,7 @@ void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
 	if (!conn->lgr || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&conn->lgr->lnk[i]))
+		if (!smc_link_active(&conn->lgr->lnk[i]))
 			continue;
 		smc_ib_sync_sg_for_cpu(&conn->lgr->lnk[i], conn->rmb_desc,
 				       DMA_FROM_DEVICE);
@@ -1750,7 +1749,7 @@ void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
 	if (!conn->lgr || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&conn->lgr->lnk[i]))
+		if (!smc_link_active(&conn->lgr->lnk[i]))
 			continue;
 		smc_ib_sync_sg_for_device(&conn->lgr->lnk[i], conn->rmb_desc,
 					  DMA_FROM_DEVICE);
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index c3ff512fd891..1c4d5439d0ff 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -349,6 +349,11 @@ static inline bool smc_link_usable(struct smc_link *lnk)
 	return true;
 }
 
+static inline bool smc_link_active(struct smc_link *lnk)
+{
+	return lnk->state == SMC_LNK_ACTIVE;
+}
+
 struct smc_sock;
 struct smc_clc_msg_accept_confirm;
 struct smc_clc_msg_local;
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index fa8cd57a9b32..df5b0a6ea848 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -428,7 +428,7 @@ static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
 	rtok_ix = 1;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 		link = &send_link->lgr->lnk[i];
-		if (link->state == SMC_LNK_ACTIVE && link != send_link) {
+		if (smc_link_active(link) && link != send_link) {
 			rkeyllc->rtoken[rtok_ix].link_id = link->link_id;
 			rkeyllc->rtoken[rtok_ix].rmb_key =
 				htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
@@ -944,7 +944,7 @@ static int smc_llc_active_link_count(struct smc_link_group *lgr)
 	int i, link_count = 0;
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&lgr->lnk[i]))
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		link_count++;
 	}
@@ -1622,7 +1622,7 @@ static void smc_llc_rx_response(struct smc_link *link,
 
 	switch (llc_type) {
 	case SMC_LLC_TEST_LINK:
-		if (link->state == SMC_LNK_ACTIVE)
+		if (smc_link_active(link))
 			complete(&link->llc_testlink_resp);
 		break;
 	case SMC_LLC_ADD_LINK:
@@ -1706,7 +1706,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
 	u8 user_data[16] = { 0 };
 	int rc;
 
-	if (link->state != SMC_LNK_ACTIVE)
+	if (!smc_link_active(link))
 		return;		/* don't reschedule worker */
 	expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
 	if (time_is_after_jiffies(expire_time)) {
@@ -1718,7 +1718,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
 	/* receive TEST LINK response over RoCE fabric */
 	rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
 						       SMC_LLC_WAIT_TIME);
-	if (link->state != SMC_LNK_ACTIVE)
+	if (!smc_link_active(link))
 		return;		/* link state changed */
 	if (rc <= 0) {
 		smcr_link_down_cond_sched(link);
-- 
2.17.1

[PATCH net 09/10] net/smc: remove freed buffer from list

[Karsten Graul]

Two buffers are allocated for each SMC connection. Each buffer is
added to a buffer list after creation. When the second buffer
allocation fails, the first buffer is freed but not deleted from
the list. This might result in crashes when another connection picks
up the freed buffer later and starts to work with it.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 6511aad3f039 ("net/smc: change smc_buf_free function parameters")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 42ba227f3e97..ca3dc6af73af 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1772,8 +1772,12 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
 		return rc;
 	/* create rmb */
 	rc = __smc_buf_create(smc, is_smcd, true);
-	if (rc)
+	if (rc) {
+		mutex_lock(&smc->conn.lgr->sndbufs_lock);
+		list_del(&smc->conn.sndbuf_desc->list);
+		mutex_unlock(&smc->conn.lgr->sndbufs_lock);
 		smc_buf_free(smc->conn.lgr, false, smc->conn.sndbuf_desc);
+	}
 	return rc;
 }
 
-- 
2.17.1

[PATCH net 10/10] net/smc: fix restoring of fallback changes

[Karsten Graul]

When a listen socket is closed then all non-accepted sockets in its
accept queue are to be released. Inside __smc_release() the helper
smc_restore_fallback_changes() restores the changes done to the socket
without to check if the clcsocket has a file set. This can result in
a crash. Fix this by checking the file pointer first.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: f536dffc0b79 ("net/smc: fix closing of fallback SMC sockets")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/af_smc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index d091509b5982..1163d51196da 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -126,8 +126,10 @@ EXPORT_SYMBOL_GPL(smc_proto6);
 
 static void smc_restore_fallback_changes(struct smc_sock *smc)
 {
-	smc->clcsock->file->private_data = smc->sk.sk_socket;
-	smc->clcsock->file = NULL;
+	if (smc->clcsock->file) { /* non-accepted sockets have no file yet */
+		smc->clcsock->file->private_data = smc->sk.sk_socket;
+		smc->clcsock->file = NULL;
+	}
 }
 
 static int __smc_release(struct smc_sock *smc)
-- 
2.17.1