[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

Currently, if a targetport has been connected to via the nvmet
config (in other words, the add_port() transport routine called, and
the nvmet port pointer stored for using in upcalls on new io), and
if the targetport is then removed (say the lldd driver decides to
unload or fully reset its hardware) and then re-added (the lldd
driver reloads or reinits its hardware), the port pointer has been
lost so there's no way to continue to post commands up to nvmet
via the transport port.

Correct by allocating a small "port context" structure that will
be linked to by the targetport. The context will save the targetport
WWN's and the nvmet port pointer to use for it.  Initial allocation
will occur when the targetport is bound to via add_port. The context
will be deallocated when remove_port() is called.  If a targetport
is removed while nvmet has the active port context, the targetport
will be unlinked from the port context before removal.  If a new
targetport is registered, the port contexts without a binding are
looked through and if the WWN's match (so it's the same as nvmet's
port context) the port context is linked to the new target port.
Thus new io can be received on the new targetport and operation
resumes with nvmet.

Additionally, this also resolves nvmet configuration changing out
from underneath of the nvme-fc target port (for example: a
nvmetcli clear).

Signed-off-by: James Smart <james.smart at broadcom.com>

---
v2:
  v1 could upcall with nvmet port pointer null (if command received
  after the port was removed from nvmet). Added check at top of
  async cmd rcv for null nvmet port and abort io on link if true.
---
 drivers/nvme/target/fc.c | 128 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 120 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 5215dc48a7b7..fbbaf68ae54f 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -110,11 +110,19 @@ struct nvmet_fc_tgtport {
 	struct list_head		ls_busylist;
 	struct list_head		assoc_list;
 	struct ida			assoc_cnt;
-	struct nvmet_port		*port;
+	struct nvmet_fc_port_entry	*pe;
 	struct kref			ref;
 	u32				max_sg_cnt;
 };
 
+struct nvmet_fc_port_entry {
+	struct nvmet_fc_tgtport		*tgtport;
+	struct nvmet_port		*port;
+	u64				node_name;
+	u64				port_name;
+	struct list_head		pe_list;
+};
+
 struct nvmet_fc_defer_fcp_req {
 	struct list_head		req_list;
 	struct nvmefc_tgt_fcp_req	*fcp_req;
@@ -132,7 +140,6 @@ struct nvmet_fc_tgt_queue {
 	atomic_t			zrspcnt;
 	atomic_t			rsn;
 	spinlock_t			qlock;
-	struct nvmet_port		*port;
 	struct nvmet_cq			nvme_cq;
 	struct nvmet_sq			nvme_sq;
 	struct nvmet_fc_tgt_assoc	*assoc;
@@ -221,6 +228,7 @@ static DEFINE_SPINLOCK(nvmet_fc_tgtlock);
 
 static LIST_HEAD(nvmet_fc_target_list);
 static DEFINE_IDA(nvmet_fc_tgtport_cnt);
+static LIST_HEAD(nvmet_fc_portentry_list);
 
 
 static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
@@ -645,7 +653,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
 	queue->qid = qid;
 	queue->sqsize = sqsize;
 	queue->assoc = assoc;
-	queue->port = assoc->tgtport->port;
 	queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
 	INIT_LIST_HEAD(&queue->fod_list);
 	INIT_LIST_HEAD(&queue->avail_defer_list);
@@ -957,6 +964,83 @@ nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
 	return ret;
 }
 
+static void
+nvmet_fc_portentry_bind(struct nvmet_fc_tgtport *tgtport,
+			struct nvmet_fc_port_entry *pe,
+			struct nvmet_port *port)
+{
+	lockdep_assert_held(&nvmet_fc_tgtlock);
+
+	pe->tgtport = tgtport;
+	tgtport->pe = pe;
+
+	pe->port = port;
+	port->priv = pe;
+
+	pe->node_name = tgtport->fc_target_port.node_name;
+	pe->port_name = tgtport->fc_target_port.port_name;
+	INIT_LIST_HEAD(&pe->pe_list);
+
+	list_add_tail(&pe->pe_list, &nvmet_fc_portentry_list);
+}
+
+static void
+nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	if (pe->tgtport)
+		pe->tgtport->pe = NULL;
+	list_del(&pe->pe_list);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+}
+
+/*
+ * called when a targetport deregisters. Breaks the relationship
+ * with the nvmet port, but leaves the port_entry in place so that
+ * re-registration can resume operation.
+ */
+static void
+nvmet_fc_portentry_unbind_tgt(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_port_entry *pe;
+	unsigned long flags;
+
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	pe = tgtport->pe;
+	if (pe)
+		pe->tgtport = NULL;
+	tgtport->pe = NULL;
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+}
+
+/*
+ * called when a new targetport is registered. Looks in the
+ * existing nvmet port_entries to see if the nvmet layer is
+ * configured for the targetport's wwn's. (the targetport existed,
+ * nvmet configured, the lldd unregistered the tgtport, and is now
+ * reregistering the same targetport).  If so, set the nvmet port
+ * port entry on the targetport.
+ */
+static void
+nvmet_fc_portentry_rebind_tgt(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_port_entry *pe;
+	unsigned long flags;
+
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
+		if ((tgtport->fc_target_port.node_name == pe->node_name) &&
+		    (tgtport->fc_target_port.port_name == pe->port_name)) {
+			WARN_ON(pe->tgtport);
+			tgtport->pe = pe;
+			pe->tgtport = tgtport;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+}
 
 /**
  * nvme_fc_register_targetport - transport entry point called by an
@@ -1034,6 +1118,8 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
 		goto out_free_newrec;
 	}
 
+	nvmet_fc_portentry_rebind_tgt(newrec);
+
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
@@ -1171,6 +1257,8 @@ nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
 {
 	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
 
+	nvmet_fc_portentry_unbind_tgt(tgtport);
+
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
 
@@ -2147,7 +2235,7 @@ nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req)
 
 
 /*
- * Actual processing routine for received FC-NVME LS Requests from the LLD
+ * Actual processing routine for received FC-NVME I/O Requests from the LLD
  */
 static void
 nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
@@ -2158,6 +2246,13 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	int ret;
 
 	/*
+	 * if there is no nvmet mapping to the targetport there
+	 * shouldn't be requests. just terminate them.
+	 */
+	if (!tgtport->pe)
+		goto transport_error;
+
+	/*
 	 * Fused commands are currently not supported in the linux
 	 * implementation.
 	 *
@@ -2184,7 +2279,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 
 	fod->req.cmd = &fod->cmdiubuf.sqe;
 	fod->req.rsp = &fod->rspiubuf.cqe;
-	fod->req.port = fod->queue->port;
+	fod->req.port = tgtport->pe->port;
 
 	/* clear any response payload */
 	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
@@ -2508,6 +2603,7 @@ static int
 nvmet_fc_add_port(struct nvmet_port *port)
 {
 	struct nvmet_fc_tgtport *tgtport;
+	struct nvmet_fc_port_entry *pe;
 	struct nvmet_fc_traddr traddr = { 0L, 0L };
 	unsigned long flags;
 	int ret;
@@ -2524,24 +2620,40 @@ nvmet_fc_add_port(struct nvmet_port *port)
 	if (ret)
 		return ret;
 
+	pe = kzalloc(sizeof(*pe), GFP_KERNEL);
+	if (!pe)
+		return -ENOMEM;
+
 	ret = -ENXIO;
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	list_for_each_entry(tgtport, &nvmet_fc_target_list, tgt_list) {
 		if ((tgtport->fc_target_port.node_name == traddr.nn) &&
 		    (tgtport->fc_target_port.port_name == traddr.pn)) {
-			tgtport->port = port;
-			ret = 0;
+			/* a FC port can only be 1 nvmet port id */
+			if (!tgtport->pe) {
+				nvmet_fc_portentry_bind(tgtport, pe, port);
+				ret = 0;
+			} else
+				ret = -EALREADY;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+
+	if (ret)
+		kfree(pe);
+
 	return ret;
 }
 
 static void
 nvmet_fc_remove_port(struct nvmet_port *port)
 {
-	/* nothing to do */
+	struct nvmet_fc_port_entry *pe = port->priv;
+
+	nvmet_fc_portentry_unbind(pe);
+
+	kfree(pe);
 }
 
 static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
-- 
2.13.1

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Ewan D. Milne]

You need to add function declarations for nvmet_fc_portentry_unbind_tgt()
and nvmet_fc_portentry_rebind_tgt().  [-Werror=implicit-function-declaration]

-Ewan

On Thu, 2018-08-09@16:48 -0700, James Smart wrote:
> Currently, if a targetport has been connected to via the nvmet
> config (in other words, the add_port() transport routine called, and
> the nvmet port pointer stored for using in upcalls on new io), and
> if the targetport is then removed (say the lldd driver decides to
> unload or fully reset its hardware) and then re-added (the lldd
> driver reloads or reinits its hardware), the port pointer has been
> lost so there's no way to continue to post commands up to nvmet
> via the transport port.
> 
> Correct by allocating a small "port context" structure that will
> be linked to by the targetport. The context will save the targetport
> WWN's and the nvmet port pointer to use for it.  Initial allocation
> will occur when the targetport is bound to via add_port. The context
> will be deallocated when remove_port() is called.  If a targetport
> is removed while nvmet has the active port context, the targetport
> will be unlinked from the port context before removal.  If a new
> targetport is registered, the port contexts without a binding are
> looked through and if the WWN's match (so it's the same as nvmet's
> port context) the port context is linked to the new target port.
> Thus new io can be received on the new targetport and operation
> resumes with nvmet.
> 
> Additionally, this also resolves nvmet configuration changing out
> from underneath of the nvme-fc target port (for example: a
> nvmetcli clear).
> 
> Signed-off-by: James Smart <james.smart at broadcom.com>
> 
> ---
> v2:
>   v1 could upcall with nvmet port pointer null (if command received
>   after the port was removed from nvmet). Added check at top of
>   async cmd rcv for null nvmet port and abort io on link if true.
> ---
>  drivers/nvme/target/fc.c | 128 ++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 120 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
> index 5215dc48a7b7..fbbaf68ae54f 100644
> --- a/drivers/nvme/target/fc.c
> +++ b/drivers/nvme/target/fc.c
> @@ -110,11 +110,19 @@ struct nvmet_fc_tgtport {
>  	struct list_head		ls_busylist;
>  	struct list_head		assoc_list;
>  	struct ida			assoc_cnt;
> -	struct nvmet_port		*port;
> +	struct nvmet_fc_port_entry	*pe;
>  	struct kref			ref;
>  	u32				max_sg_cnt;
>  };
>  
> +struct nvmet_fc_port_entry {
> +	struct nvmet_fc_tgtport		*tgtport;
> +	struct nvmet_port		*port;
> +	u64				node_name;
> +	u64				port_name;
> +	struct list_head		pe_list;
> +};
> +
>  struct nvmet_fc_defer_fcp_req {
>  	struct list_head		req_list;
>  	struct nvmefc_tgt_fcp_req	*fcp_req;
> @@ -132,7 +140,6 @@ struct nvmet_fc_tgt_queue {
>  	atomic_t			zrspcnt;
>  	atomic_t			rsn;
>  	spinlock_t			qlock;
> -	struct nvmet_port		*port;
>  	struct nvmet_cq			nvme_cq;
>  	struct nvmet_sq			nvme_sq;
>  	struct nvmet_fc_tgt_assoc	*assoc;
> @@ -221,6 +228,7 @@ static DEFINE_SPINLOCK(nvmet_fc_tgtlock);
>  
>  static LIST_HEAD(nvmet_fc_target_list);
>  static DEFINE_IDA(nvmet_fc_tgtport_cnt);
> +static LIST_HEAD(nvmet_fc_portentry_list);
>  
> 
>  static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
> @@ -645,7 +653,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
>  	queue->qid = qid;
>  	queue->sqsize = sqsize;
>  	queue->assoc = assoc;
> -	queue->port = assoc->tgtport->port;
>  	queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
>  	INIT_LIST_HEAD(&queue->fod_list);
>  	INIT_LIST_HEAD(&queue->avail_defer_list);
> @@ -957,6 +964,83 @@ nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
>  	return ret;
>  }
>  
> +static void
> +nvmet_fc_portentry_bind(struct nvmet_fc_tgtport *tgtport,
> +			struct nvmet_fc_port_entry *pe,
> +			struct nvmet_port *port)
> +{
> +	lockdep_assert_held(&nvmet_fc_tgtlock);
> +
> +	pe->tgtport = tgtport;
> +	tgtport->pe = pe;
> +
> +	pe->port = port;
> +	port->priv = pe;
> +
> +	pe->node_name = tgtport->fc_target_port.node_name;
> +	pe->port_name = tgtport->fc_target_port.port_name;
> +	INIT_LIST_HEAD(&pe->pe_list);
> +
> +	list_add_tail(&pe->pe_list, &nvmet_fc_portentry_list);
> +}
> +
> +static void
> +nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	if (pe->tgtport)
> +		pe->tgtport->pe = NULL;
> +	list_del(&pe->pe_list);
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
> +
> +/*
> + * called when a targetport deregisters. Breaks the relationship
> + * with the nvmet port, but leaves the port_entry in place so that
> + * re-registration can resume operation.
> + */
> +static void
> +nvmet_fc_portentry_unbind_tgt(struct nvmet_fc_tgtport *tgtport)
> +{
> +	struct nvmet_fc_port_entry *pe;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	pe = tgtport->pe;
> +	if (pe)
> +		pe->tgtport = NULL;
> +	tgtport->pe = NULL;
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
> +
> +/*
> + * called when a new targetport is registered. Looks in the
> + * existing nvmet port_entries to see if the nvmet layer is
> + * configured for the targetport's wwn's. (the targetport existed,
> + * nvmet configured, the lldd unregistered the tgtport, and is now
> + * reregistering the same targetport).  If so, set the nvmet port
> + * port entry on the targetport.
> + */
> +static void
> +nvmet_fc_portentry_rebind_tgt(struct nvmet_fc_tgtport *tgtport)
> +{
> +	struct nvmet_fc_port_entry *pe;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
> +		if ((tgtport->fc_target_port.node_name == pe->node_name) &&
> +		    (tgtport->fc_target_port.port_name == pe->port_name)) {
> +			WARN_ON(pe->tgtport);
> +			tgtport->pe = pe;
> +			pe->tgtport = tgtport;
> +			break;
> +		}
> +	}
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
>  
>  /**
>   * nvme_fc_register_targetport - transport entry point called by an
> @@ -1034,6 +1118,8 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
>  		goto out_free_newrec;
>  	}
>  
> +	nvmet_fc_portentry_rebind_tgt(newrec);
> +
>  	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
>  	list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
>  	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> @@ -1171,6 +1257,8 @@ nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
>  {
>  	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
>  
> +	nvmet_fc_portentry_unbind_tgt(tgtport);
> +
>  	/* terminate any outstanding associations */
>  	__nvmet_fc_free_assocs(tgtport);
>  
> @@ -2147,7 +2235,7 @@ nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req)
>  
> 
>  /*
> - * Actual processing routine for received FC-NVME LS Requests from the LLD
> + * Actual processing routine for received FC-NVME I/O Requests from the LLD
>   */
>  static void
>  nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
> @@ -2158,6 +2246,13 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
>  	int ret;
>  
>  	/*
> +	 * if there is no nvmet mapping to the targetport there
> +	 * shouldn't be requests. just terminate them.
> +	 */
> +	if (!tgtport->pe)
> +		goto transport_error;
> +
> +	/*
>  	 * Fused commands are currently not supported in the linux
>  	 * implementation.
>  	 *
> @@ -2184,7 +2279,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
>  
>  	fod->req.cmd = &fod->cmdiubuf.sqe;
>  	fod->req.rsp = &fod->rspiubuf.cqe;
> -	fod->req.port = fod->queue->port;
> +	fod->req.port = tgtport->pe->port;
>  
>  	/* clear any response payload */
>  	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
> @@ -2508,6 +2603,7 @@ static int
>  nvmet_fc_add_port(struct nvmet_port *port)
>  {
>  	struct nvmet_fc_tgtport *tgtport;
> +	struct nvmet_fc_port_entry *pe;
>  	struct nvmet_fc_traddr traddr = { 0L, 0L };
>  	unsigned long flags;
>  	int ret;
> @@ -2524,24 +2620,40 @@ nvmet_fc_add_port(struct nvmet_port *port)
>  	if (ret)
>  		return ret;
>  
> +	pe = kzalloc(sizeof(*pe), GFP_KERNEL);
> +	if (!pe)
> +		return -ENOMEM;
> +
>  	ret = -ENXIO;
>  	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
>  	list_for_each_entry(tgtport, &nvmet_fc_target_list, tgt_list) {
>  		if ((tgtport->fc_target_port.node_name == traddr.nn) &&
>  		    (tgtport->fc_target_port.port_name == traddr.pn)) {
> -			tgtport->port = port;
> -			ret = 0;
> +			/* a FC port can only be 1 nvmet port id */
> +			if (!tgtport->pe) {
> +				nvmet_fc_portentry_bind(tgtport, pe, port);
> +				ret = 0;
> +			} else
> +				ret = -EALREADY;
>  			break;
>  		}
>  	}
>  	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +
> +	if (ret)
> +		kfree(pe);
> +
>  	return ret;
>  }
>  
>  static void
>  nvmet_fc_remove_port(struct nvmet_port *port)
>  {
> -	/* nothing to do */
> +	struct nvmet_fc_port_entry *pe = port->priv;
> +
> +	nvmet_fc_portentry_unbind(pe);
> +
> +	kfree(pe);
>  }
>  
>  static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

On 8/10/2018 10:53 AM, Ewan D. Milne wrote:
> You need to add function declarations for nvmet_fc_portentry_unbind_tgt()
> and nvmet_fc_portentry_rebind_tgt().  [-Werror=implicit-function-declaration]
>
> -Ewan

??? They are all declared ahead of use

-- james

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Ewan D. Milne]

On Fri, 2018-08-10@16:21 -0700, James Smart wrote:
> On 8/10/2018 10:53 AM, Ewan D. Milne wrote:
> > You need to add function declarations for nvmet_fc_portentry_unbind_tgt()
> > and nvmet_fc_portentry_rebind_tgt().  [-Werror=implicit-function-declaration]
> >
> > -Ewan
> 
> ??  They are all declared ahead of use
> 
> -- james
> 

They weren't for me, but that's because I applied the patch to my
working tree, rather than nvme-4.19, and the functions ended up
getting placed down further in the file somehow.

-Ewan

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Ewan D. Milne]

OK, so with this patch applied on the target, I'm seeing undesirable
behavior on the NVMe/FC initiator side when the target is not configured.

Without this patch, if the NVMe/FC initiator and the NVMe/FC soft target
are booted, but the target is not configured, an attempt to connect on
the initiator via "nvme connect" will return from the CLI immediately,
and the connection attempts will commence, e.g.:

[  191.233854] nvme nvme1: Connect Invalid Data Parameter, subsysnqn "testnqn"
[  191.241650] nvme nvme1: NVME-FC{0}: reset: Reconnect attempt failed (16770)
[  191.249421] nvme nvme1: NVME-FC{0}: Reconnect attempt in 10 seconds

then if I configure the target, it will connect.  Great.

[  241.612730] nvme nvme1: NVME-FC{0}: controller connect complete

--

However, with this patch applied on the target, the nvme-cli connect
command on the intiator (with an unconfigured target) hangs:

[ 1516.041039] nvme            D ffff942449a1e970     0  1850   1849 0x00000080
[ 1516.048924] Call Trace:
[ 1516.051650]  [<ffffffffa46e1a88>] ? enqueue_task_fair+0x208/0x6c0
[ 1516.058451]  [<ffffffffa4d5fea9>] schedule+0x29/0x70
[ 1516.063989]  [<ffffffffa4d5d7f1>] schedule_timeout+0x221/0x2d0
[ 1516.070498]  [<ffffffffa46d1e2f>] ? ttwu_do_activate+0x6f/0x80
[ 1516.077017]  [<ffffffffa46d55b0>] ? try_to_wake_up+0x190/0x390
[ 1516.083525]  [<ffffffffa4d6025d>] wait_for_completion+0xfd/0x140
[ 1516.090228]  [<ffffffffa46d5870>] ? wake_up_state+0x20/0x20
[ 1516.096446]  [<ffffffffa46b902d>] flush_work+0xfd/0x190
[ 1516.102276]  [<ffffffffa46b5e20>] ? move_linked_works+0x90/0x90
[ 1516.108882]  [<ffffffffa46b92ef>] flush_delayed_work+0x3f/0x50
[ 1516.115429]  [<ffffffffc00c0cbd>] nvme_fc_create_ctrl+0x72d/0x7a0 [nvme_fc]
[ 1516.123201]  [<ffffffffc011c5b6>] nvmf_dev_write+0xa26/0xbef [nvme_fabrics]
[ 1516.130981]  [<ffffffffa48f6307>] ? security_file_permission+0x27/0xa0
[ 1516.138265]  [<ffffffffa483eba0>] vfs_write+0xc0/0x1f0
[ 1516.143997]  [<ffffffffa483f9bf>] SyS_write+0x7f/0xf0
[ 1516.149633]  [<ffffffffa4d6cdef>] system_call_fastpath+0x1c/0x21

[ 1508.006831] kworker/u384:3  D ffff94244dcad7e0     0   578      2 0x00000000
[ 1508.014736] Workqueue: nvme-wq nvme_fc_connect_ctrl_work [nvme_fc]
[ 1508.021642] Call Trace:
[ 1508.024368]  [<ffffffffa4d5fea9>] schedule+0x29/0x70
[ 1508.029907]  [<ffffffffa4d5d738>] schedule_timeout+0x168/0x2d0
[ 1508.036422]  [<ffffffffa46a83f0>] ? __internal_add_timer+0x130/0x130
[ 1508.043515]  [<ffffffffa46ffc02>] ? ktime_get_ts64+0x52/0xf0
[ 1508.049847]  [<ffffffffa4d5f3bd>] io_schedule_timeout+0xad/0x130
[ 1508.056551]  [<ffffffffa4d603a5>] wait_for_completion_io_timeout+0x105/0x140
[ 1508.064421]  [<ffffffffa46d5870>] ? wake_up_state+0x20/0x20
[ 1508.070674]  [<ffffffffa494869b>] blk_execute_rq+0xab/0x150
[ 1508.076897]  [<ffffffffc00cd8cf>] __nvme_submit_sync_cmd+0x6f/0xf0 [nvme_core]
[ 1508.084958]  [<ffffffffc011b908>] nvmf_connect_admin_queue+0x128/0x1a0 [nvme_fabrics]
[ 1508.093718]  [<ffffffffc00bfac0>] nvme_fc_create_association+0x3a0/0x9c0 [nvme_fc]
[ 1508.102167]  [<ffffffffc00c00fe>] nvme_fc_connect_ctrl_work+0x1e/0x60 [nvme_fc]
[ 1508.110323]  [<ffffffffa46b88af>] process_one_work+0x17f/0x440
[ 1508.116831]  [<ffffffffa46b9a98>] worker_thread+0x278/0x3c0
[ 1508.123050]  [<ffffffffa46b9820>] ? manage_workers.isra.24+0x2a0/0x2a0
[ 1508.130333]  [<ffffffffa46c0a31>] kthread+0xd1/0xe0
[ 1508.135774]  [<ffffffffa46c0960>] ? insert_kthread_work+0x40/0x40
[ 1508.142574]  [<ffffffffa4d6cc37>] ret_from_fork_nospec_begin+0x21/0x21
[ 1508.149859]  [<ffffffffa46c0960>] ? insert_kthread_work+0x40/0x40

configuring the target does not help at this point.

I've haven't figured out exactly what is wrong yet, but thought I'd
bring this up...

Clearly, separate from the target side issue, having the initiator hang
regardless of what the target code is doing is a bad thing.  There's
supposed to be an admin queue timeout, but it didn't work here.

-Ewan

On Thu, 2018-08-09@16:48 -0700, James Smart wrote:
> Currently, if a targetport has been connected to via the nvmet
> config (in other words, the add_port() transport routine called, and
> the nvmet port pointer stored for using in upcalls on new io), and
> if the targetport is then removed (say the lldd driver decides to
> unload or fully reset its hardware) and then re-added (the lldd
> driver reloads or reinits its hardware), the port pointer has been
> lost so there's no way to continue to post commands up to nvmet
> via the transport port.
> 
> Correct by allocating a small "port context" structure that will
> be linked to by the targetport. The context will save the targetport
> WWN's and the nvmet port pointer to use for it.  Initial allocation
> will occur when the targetport is bound to via add_port. The context
> will be deallocated when remove_port() is called.  If a targetport
> is removed while nvmet has the active port context, the targetport
> will be unlinked from the port context before removal.  If a new
> targetport is registered, the port contexts without a binding are
> looked through and if the WWN's match (so it's the same as nvmet's
> port context) the port context is linked to the new target port.
> Thus new io can be received on the new targetport and operation
> resumes with nvmet.
> 
> Additionally, this also resolves nvmet configuration changing out
> from underneath of the nvme-fc target port (for example: a
> nvmetcli clear).
> 
> Signed-off-by: James Smart <james.smart at broadcom.com>
> 
> ---
> v2:
>   v1 could upcall with nvmet port pointer null (if command received
>   after the port was removed from nvmet). Added check at top of
>   async cmd rcv for null nvmet port and abort io on link if true.
> ---
>  drivers/nvme/target/fc.c | 128 ++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 120 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
> index 5215dc48a7b7..fbbaf68ae54f 100644
> --- a/drivers/nvme/target/fc.c
> +++ b/drivers/nvme/target/fc.c
> @@ -110,11 +110,19 @@ struct nvmet_fc_tgtport {
>  	struct list_head		ls_busylist;
>  	struct list_head		assoc_list;
>  	struct ida			assoc_cnt;
> -	struct nvmet_port		*port;
> +	struct nvmet_fc_port_entry	*pe;
>  	struct kref			ref;
>  	u32				max_sg_cnt;
>  };
>  
> +struct nvmet_fc_port_entry {
> +	struct nvmet_fc_tgtport		*tgtport;
> +	struct nvmet_port		*port;
> +	u64				node_name;
> +	u64				port_name;
> +	struct list_head		pe_list;
> +};
> +
>  struct nvmet_fc_defer_fcp_req {
>  	struct list_head		req_list;
>  	struct nvmefc_tgt_fcp_req	*fcp_req;
> @@ -132,7 +140,6 @@ struct nvmet_fc_tgt_queue {
>  	atomic_t			zrspcnt;
>  	atomic_t			rsn;
>  	spinlock_t			qlock;
> -	struct nvmet_port		*port;
>  	struct nvmet_cq			nvme_cq;
>  	struct nvmet_sq			nvme_sq;
>  	struct nvmet_fc_tgt_assoc	*assoc;
> @@ -221,6 +228,7 @@ static DEFINE_SPINLOCK(nvmet_fc_tgtlock);
>  
>  static LIST_HEAD(nvmet_fc_target_list);
>  static DEFINE_IDA(nvmet_fc_tgtport_cnt);
> +static LIST_HEAD(nvmet_fc_portentry_list);
>  
> 
>  static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
> @@ -645,7 +653,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
>  	queue->qid = qid;
>  	queue->sqsize = sqsize;
>  	queue->assoc = assoc;
> -	queue->port = assoc->tgtport->port;
>  	queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
>  	INIT_LIST_HEAD(&queue->fod_list);
>  	INIT_LIST_HEAD(&queue->avail_defer_list);
> @@ -957,6 +964,83 @@ nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
>  	return ret;
>  }
>  
> +static void
> +nvmet_fc_portentry_bind(struct nvmet_fc_tgtport *tgtport,
> +			struct nvmet_fc_port_entry *pe,
> +			struct nvmet_port *port)
> +{
> +	lockdep_assert_held(&nvmet_fc_tgtlock);
> +
> +	pe->tgtport = tgtport;
> +	tgtport->pe = pe;
> +
> +	pe->port = port;
> +	port->priv = pe;
> +
> +	pe->node_name = tgtport->fc_target_port.node_name;
> +	pe->port_name = tgtport->fc_target_port.port_name;
> +	INIT_LIST_HEAD(&pe->pe_list);
> +
> +	list_add_tail(&pe->pe_list, &nvmet_fc_portentry_list);
> +}
> +
> +static void
> +nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	if (pe->tgtport)
> +		pe->tgtport->pe = NULL;
> +	list_del(&pe->pe_list);
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
> +
> +/*
> + * called when a targetport deregisters. Breaks the relationship
> + * with the nvmet port, but leaves the port_entry in place so that
> + * re-registration can resume operation.
> + */
> +static void
> +nvmet_fc_portentry_unbind_tgt(struct nvmet_fc_tgtport *tgtport)
> +{
> +	struct nvmet_fc_port_entry *pe;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	pe = tgtport->pe;
> +	if (pe)
> +		pe->tgtport = NULL;
> +	tgtport->pe = NULL;
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
> +
> +/*
> + * called when a new targetport is registered. Looks in the
> + * existing nvmet port_entries to see if the nvmet layer is
> + * configured for the targetport's wwn's. (the targetport existed,
> + * nvmet configured, the lldd unregistered the tgtport, and is now
> + * reregistering the same targetport).  If so, set the nvmet port
> + * port entry on the targetport.
> + */
> +static void
> +nvmet_fc_portentry_rebind_tgt(struct nvmet_fc_tgtport *tgtport)
> +{
> +	struct nvmet_fc_port_entry *pe;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
> +	list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
> +		if ((tgtport->fc_target_port.node_name == pe->node_name) &&
> +		    (tgtport->fc_target_port.port_name == pe->port_name)) {
> +			WARN_ON(pe->tgtport);
> +			tgtport->pe = pe;
> +			pe->tgtport = tgtport;
> +			break;
> +		}
> +	}
> +	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +}
>  
>  /**
>   * nvme_fc_register_targetport - transport entry point called by an
> @@ -1034,6 +1118,8 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
>  		goto out_free_newrec;
>  	}
>  
> +	nvmet_fc_portentry_rebind_tgt(newrec);
> +
>  	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
>  	list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
>  	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> @@ -1171,6 +1257,8 @@ nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
>  {
>  	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
>  
> +	nvmet_fc_portentry_unbind_tgt(tgtport);
> +
>  	/* terminate any outstanding associations */
>  	__nvmet_fc_free_assocs(tgtport);
>  
> @@ -2147,7 +2235,7 @@ nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req)
>  
> 
>  /*
> - * Actual processing routine for received FC-NVME LS Requests from the LLD
> + * Actual processing routine for received FC-NVME I/O Requests from the LLD
>   */
>  static void
>  nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
> @@ -2158,6 +2246,13 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
>  	int ret;
>  
>  	/*
> +	 * if there is no nvmet mapping to the targetport there
> +	 * shouldn't be requests. just terminate them.
> +	 */
> +	if (!tgtport->pe)
> +		goto transport_error;
> +
> +	/*
>  	 * Fused commands are currently not supported in the linux
>  	 * implementation.
>  	 *
> @@ -2184,7 +2279,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
>  
>  	fod->req.cmd = &fod->cmdiubuf.sqe;
>  	fod->req.rsp = &fod->rspiubuf.cqe;
> -	fod->req.port = fod->queue->port;
> +	fod->req.port = tgtport->pe->port;
>  
>  	/* clear any response payload */
>  	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
> @@ -2508,6 +2603,7 @@ static int
>  nvmet_fc_add_port(struct nvmet_port *port)
>  {
>  	struct nvmet_fc_tgtport *tgtport;
> +	struct nvmet_fc_port_entry *pe;
>  	struct nvmet_fc_traddr traddr = { 0L, 0L };
>  	unsigned long flags;
>  	int ret;
> @@ -2524,24 +2620,40 @@ nvmet_fc_add_port(struct nvmet_port *port)
>  	if (ret)
>  		return ret;
>  
> +	pe = kzalloc(sizeof(*pe), GFP_KERNEL);
> +	if (!pe)
> +		return -ENOMEM;
> +
>  	ret = -ENXIO;
>  	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
>  	list_for_each_entry(tgtport, &nvmet_fc_target_list, tgt_list) {
>  		if ((tgtport->fc_target_port.node_name == traddr.nn) &&
>  		    (tgtport->fc_target_port.port_name == traddr.pn)) {
> -			tgtport->port = port;
> -			ret = 0;
> +			/* a FC port can only be 1 nvmet port id */
> +			if (!tgtport->pe) {
> +				nvmet_fc_portentry_bind(tgtport, pe, port);
> +				ret = 0;
> +			} else
> +				ret = -EALREADY;
>  			break;
>  		}
>  	}
>  	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
> +
> +	if (ret)
> +		kfree(pe);
> +
>  	return ret;
>  }
>  
>  static void
>  nvmet_fc_remove_port(struct nvmet_port *port)
>  {
> -	/* nothing to do */
> +	struct nvmet_fc_port_entry *pe = port->priv;
> +
> +	nvmet_fc_portentry_unbind(pe);
> +
> +	kfree(pe);
>  }
>  
>  static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

On 8/10/2018 1:50 PM, Ewan D. Milne wrote:
> OK, so with this patch applied on the target, I'm seeing undesirable
> behavior on the NVMe/FC initiator side when the target is not configured.
> 
> Without this patch, if the NVMe/FC initiator and the NVMe/FC soft target
> are booted, but the target is not configured, an attempt to connect on
> the initiator via "nvme connect" will return from the CLI immediately,
> and the connection attempts will commence, e.g.:
> 
> [  191.233854] nvme nvme1: Connect Invalid Data Parameter, subsysnqn "testnqn"
> [  191.241650] nvme nvme1: NVME-FC{0}: reset: Reconnect attempt failed (16770)
> [  191.249421] nvme nvme1: NVME-FC{0}: Reconnect attempt in 10 seconds
> 
> then if I configure the target, it will connect.  Great.
> 
> [  241.612730] nvme nvme1: NVME-FC{0}: controller connect complete
> 
> --
> 
> However, with this patch applied on the target, the nvme-cli connect
> command on the intiator (with an unconfigured target) hangs:

ok - but I'd like to be very clear:  This has to be a case where the 
nvmet target wasn't configured since boot (thus you see the above, and 
will see the same with and without patch), then was configured, then 
wasn't (via a "nvmetcli clear").  In other words, I believe you only see 
this point if nvmetcli clears the config after there's been a prior 
binding with a fc port.

> 
> [ 1516.041039] nvme            D ffff942449a1e970     0  1850   1849 0x00000080
> [ 1516.048924] Call Trace:
> [ 1516.051650]  [<ffffffffa46e1a88>] ? enqueue_task_fair+0x208/0x6c0
> [ 1516.058451]  [<ffffffffa4d5fea9>] schedule+0x29/0x70
> [ 1516.063989]  [<ffffffffa4d5d7f1>] schedule_timeout+0x221/0x2d0
> [ 1516.070498]  [<ffffffffa46d1e2f>] ? ttwu_do_activate+0x6f/0x80
> [ 1516.077017]  [<ffffffffa46d55b0>] ? try_to_wake_up+0x190/0x390
> [ 1516.083525]  [<ffffffffa4d6025d>] wait_for_completion+0xfd/0x140
> [ 1516.090228]  [<ffffffffa46d5870>] ? wake_up_state+0x20/0x20
> [ 1516.096446]  [<ffffffffa46b902d>] flush_work+0xfd/0x190
> [ 1516.102276]  [<ffffffffa46b5e20>] ? move_linked_works+0x90/0x90
> [ 1516.108882]  [<ffffffffa46b92ef>] flush_delayed_work+0x3f/0x50
> [ 1516.115429]  [<ffffffffc00c0cbd>] nvme_fc_create_ctrl+0x72d/0x7a0 [nvme_fc]
> [ 1516.123201]  [<ffffffffc011c5b6>] nvmf_dev_write+0xa26/0xbef [nvme_fabrics]
> [ 1516.130981]  [<ffffffffa48f6307>] ? security_file_permission+0x27/0xa0
> [ 1516.138265]  [<ffffffffa483eba0>] vfs_write+0xc0/0x1f0
> [ 1516.143997]  [<ffffffffa483f9bf>] SyS_write+0x7f/0xf0
> [ 1516.149633]  [<ffffffffa4d6cdef>] system_call_fastpath+0x1c/0x21
> 
> [ 1508.006831] kworker/u384:3  D ffff94244dcad7e0     0   578      2 0x00000000
> [ 1508.014736] Workqueue: nvme-wq nvme_fc_connect_ctrl_work [nvme_fc]
> [ 1508.021642] Call Trace:
> [ 1508.024368]  [<ffffffffa4d5fea9>] schedule+0x29/0x70
> [ 1508.029907]  [<ffffffffa4d5d738>] schedule_timeout+0x168/0x2d0
> [ 1508.036422]  [<ffffffffa46a83f0>] ? __internal_add_timer+0x130/0x130
> [ 1508.043515]  [<ffffffffa46ffc02>] ? ktime_get_ts64+0x52/0xf0
> [ 1508.049847]  [<ffffffffa4d5f3bd>] io_schedule_timeout+0xad/0x130
> [ 1508.056551]  [<ffffffffa4d603a5>] wait_for_completion_io_timeout+0x105/0x140
> [ 1508.064421]  [<ffffffffa46d5870>] ? wake_up_state+0x20/0x20
> [ 1508.070674]  [<ffffffffa494869b>] blk_execute_rq+0xab/0x150
> [ 1508.076897]  [<ffffffffc00cd8cf>] __nvme_submit_sync_cmd+0x6f/0xf0 [nvme_core]
> [ 1508.084958]  [<ffffffffc011b908>] nvmf_connect_admin_queue+0x128/0x1a0 [nvme_fabrics]
> [ 1508.093718]  [<ffffffffc00bfac0>] nvme_fc_create_association+0x3a0/0x9c0 [nvme_fc]
> [ 1508.102167]  [<ffffffffc00c00fe>] nvme_fc_connect_ctrl_work+0x1e/0x60 [nvme_fc]
> [ 1508.110323]  [<ffffffffa46b88af>] process_one_work+0x17f/0x440
> [ 1508.116831]  [<ffffffffa46b9a98>] worker_thread+0x278/0x3c0
> [ 1508.123050]  [<ffffffffa46b9820>] ? manage_workers.isra.24+0x2a0/0x2a0
> [ 1508.130333]  [<ffffffffa46c0a31>] kthread+0xd1/0xe0
> [ 1508.135774]  [<ffffffffa46c0960>] ? insert_kthread_work+0x40/0x40
> [ 1508.142574]  [<ffffffffa4d6cc37>] ret_from_fork_nospec_begin+0x21/0x21
> [ 1508.149859]  [<ffffffffa46c0960>] ? insert_kthread_work+0x40/0x40

I believe this to be the case which was added in v2 which has the 
transport abort the newly received command, as the abort should be the
notification back to the host.  And I'm guessing there's a bug in the 
lldd for the abort (assume lpfc?).

what doesn't make sense: this shouldn't be much different from the 
without patch case, as the port pointer in the fc port should be at
best stale and could be doing any number of things.

> 
> configuring the target does not help at this point.
> 
> I've haven't figured out exactly what is wrong yet, but thought I'd
> bring this up...
> 
> Clearly, separate from the target side issue, having the initiator hang
> regardless of what the target code is doing is a bad thing.  There's
> supposed to be an admin queue timeout, but it didn't work here.
> 
> -Ewan

I agree - the admin queue timeout should be what works around this as it 
would then have the host send it's own abort to recover. We do need to 
see why it didn't occur.

I'll put it through some additional testing and will post any findings.

-- james

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Christoph Hellwig]

Ewan, James: what is the conclusion on this patch?   The discussion
seems to have faded.

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

The patch is good - but did bring out an error in lpfc.? So we're hosed 
either way:? w/o it - we have fc transport using a pointer after free 
corrupting whatever it is; w/ it lpfc doesn't clean up so the controller 
hangs.

I guess I would prefer to pick up the fix and I'll work on getting lpfc 
fixed.

-- james



On 9/5/2018 12:56 PM, Christoph Hellwig wrote:
> Ewan, James: what is the conclusion on this patch?   The discussion
> seems to have faded.

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Christoph Hellwig]

On Wed, Sep 05, 2018@01:12:29PM -0700, James Smart wrote:
> The patch is good - but did bring out an error in lpfc.? So we're hosed
> either way:? w/o it - we have fc transport using a pointer after free
> corrupting whatever it is; w/ it lpfc doesn't clean up so the controller
> hangs.
> 
> I guess I would prefer to pick up the fix and I'll work on getting lpfc
> fixed.

I'll merge it for 4.20 for now due to the issue of uncovering another
bug.  If you have a got reason for it to got into 4.19 instead let me
know and I can still move it around.

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Ewan D. Milne]

On Wed, 2018-09-05@12:56 -0700, Christoph Hellwig wrote:
> Ewan, James: what is the conclusion on this patch?   The discussion
> seems to have faded.

I think where we left it was that I found a case where the patch
exposed a problem that James thought needed a fix in the lpfc driver.

The basic problem with the tree right now is that "nvmetcli clear"
frees the nvmet_port object but nvmet_fc_tgtport still points to the
freed memory.  So, if a subsequent connect request comes in, we
reference the freed memory.  I normally run with slub_debug=FZPU, so I
get a crash right away.  Otherwise you might never notice (but our
QE people have seen odd behavior, which sent me looking...)

With James' v2 patch, he addresses the problem, however now there is
a different one, which is that if the target is not configured, and
a connect request comes in, we hang on the initiator side.

This is all with the NVMe/FC soft target.

-Ewan

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

On 9/5/2018 1:24 PM, Ewan D. Milne wrote:
> On Wed, 2018-09-05@12:56 -0700, Christoph Hellwig wrote:
>> Ewan, James: what is the conclusion on this patch?   The discussion
>> seems to have faded.
> 
> I think where we left it was that I found a case where the patch
> exposed a problem that James thought needed a fix in the lpfc driver.
> 
> The basic problem with the tree right now is that "nvmetcli clear"
> frees the nvmet_port object but nvmet_fc_tgtport still points to the
> freed memory.  So, if a subsequent connect request comes in, we
> reference the freed memory.  I normally run with slub_debug=FZPU, so I
> get a crash right away.  Otherwise you might never notice (but our
> QE people have seen odd behavior, which sent me looking...)
> 
> With James' v2 patch, he addresses the problem, however now there is
> a different one, which is that if the target is not configured, and
> a connect request comes in, we hang on the initiator side.
> 
> This is all with the NVMe/FC soft target.
> 
> -Ewan

I have no problems with the nvme soft target, but my soft target did 
have the fcloop fix for dropped LS requests, which Christoph pulled in a 
few days ago.

-- james

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[Christoph Hellwig]

Thanks,

applied to nvme-4.20.

[PATCH v2] nvmet_fc: support target port removal with nvmet layer

[James Smart]

On 9/11/2018 12:35 AM, Christoph Hellwig wrote:
> Thanks,
>
> applied to nvme-4.20.

thanks