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zfcp: patches for 3.6-rc

PATCH New Steffen Maier 1 participant 9 messages Sep 4, 2012

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#0 lore raw

cover zfcp: patches for 3.6-rc

James,

here is a series of zfcp fixes for the current 3.6-rc.
The patches apply on top of the current fixes branch of your scsi.git.

Steffen

Linux on System z Development

IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter
Geschaeftsfuehrung: Dirk Wittkopp
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294

#1 lore raw

PATCH 1/8 zfcp: Adapt to new FC_PORTSPEED semantics

From: Steffen Maier <[email protected]>

Commit a9277e7783651d4e0a849f7988340b1c1cf748a4
"[SCSI] scsi_transport_fc: Getting FC Port Speed in sync with FC-GS" changed the semantics of FC_PORTSPEED defines to
FDMI port attributes of FC-HBA/SM-HBA
which is different from the previous bit reversed
Report Port Speed Capabilities (RPSC) ELS of FC-GS/FC-LS.

Zfcp showed "10 Gbit" instead of "4 Gbit" for supported_speeds. It now uses explicit bit conversion as the other LLDs already do, in order to be independent of the kernel bit semantics. See also http://marc.info/?l=linux-scsi&m=134452926830730&w=2

---
 drivers/s390/scsi/zfcp_fsf.c |   34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)
drivers/s390/scsi/zfcp_fsf.c +32 -2
@@ -437,6 +437,34 @@ void zfcp_fsf_req_dismiss_all(struct zfc
 	}
 }
 
+#define ZFCP_FSF_PORTSPEED_1GBIT	(1 <<  0)
+#define ZFCP_FSF_PORTSPEED_2GBIT	(1 <<  1)
+#define ZFCP_FSF_PORTSPEED_4GBIT	(1 <<  2)
+#define ZFCP_FSF_PORTSPEED_10GBIT	(1 <<  3)
+#define ZFCP_FSF_PORTSPEED_8GBIT	(1 <<  4)
+#define ZFCP_FSF_PORTSPEED_16GBIT	(1 <<  5)
+#define ZFCP_FSF_PORTSPEED_NOT_NEGOTIATED (1 << 15)
+
+static u32 zfcp_fsf_convert_portspeed(u32 fsf_speed)
+{
+	u32 fdmi_speed = 0;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_1GBIT)
+		fdmi_speed |= FC_PORTSPEED_1GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_2GBIT)
+		fdmi_speed |= FC_PORTSPEED_2GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_4GBIT)
+		fdmi_speed |= FC_PORTSPEED_4GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_10GBIT)
+		fdmi_speed |= FC_PORTSPEED_10GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_8GBIT)
+		fdmi_speed |= FC_PORTSPEED_8GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_16GBIT)
+		fdmi_speed |= FC_PORTSPEED_16GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_NOT_NEGOTIATED)
+		fdmi_speed |= FC_PORTSPEED_NOT_NEGOTIATED;
+	return fdmi_speed;
+}
+
 static int zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *req)
 {
 	struct fsf_qtcb_bottom_config *bottom = &req->qtcb->bottom.config;
@@ -456,7 +484,8 @@ static int zfcp_fsf_exchange_config_eval
 	fc_host_port_name(shost) = nsp->fl_wwpn;
 	fc_host_node_name(shost) = nsp->fl_wwnn;
 	fc_host_port_id(shost) = ntoh24(bottom->s_id);
-	fc_host_speed(shost) = bottom->fc_link_speed;
+	fc_host_speed(shost) =
+		zfcp_fsf_convert_portspeed(bottom->fc_link_speed);
 	fc_host_supported_classes(shost) = FC_COS_CLASS2 | FC_COS_CLASS3;
 
 	adapter->hydra_version = bottom->adapter_type;
@@ -580,7 +609,8 @@ static void zfcp_fsf_exchange_port_evalu
 	} else
 		fc_host_permanent_port_name(shost) = fc_host_port_name(shost);
 	fc_host_maxframe_size(shost) = bottom->maximum_frame_size;
-	fc_host_supported_speeds(shost) = bottom->supported_speed;
+	fc_host_supported_speeds(shost) =
+		zfcp_fsf_convert_portspeed(bottom->supported_speed);
 	memcpy(fc_host_supported_fc4s(shost), bottom->supported_fc4_types,
 	       FC_FC4_LIST_SIZE);
 	memcpy(fc_host_active_fc4s(shost), bottom->active_fc4_types,
#2 lore raw

PATCH 2/8 zfcp: Make trace record tags unique

In reply to Steffen Maier

From: Steffen Maier <[email protected]>

Duplicate fssrh_2 from a54ca0f62f953898b05549391ac2a8a4dad6482b "[SCSI] zfcp: Redesign of the debug tracing for HBA records." complicates distinction of generic status read response from local link up.
Duplicate fsscth1 from 2c55b750a884b86dea8b4cc5f15e1484cc47a25c "[SCSI] zfcp: Redesign of the debug tracing for SAN records." complicates distinction of good common transport response from invalid port handle.

---
 drivers/s390/scsi/zfcp_fsf.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/s390/scsi/zfcp_fsf.c +2 -2
@@ -219,7 +219,7 @@ static void zfcp_fsf_status_read_handler
 		return;
 	}
 
-	zfcp_dbf_hba_fsf_uss("fssrh_2", req);
+	zfcp_dbf_hba_fsf_uss("fssrh_4", req);
 
 	switch (sr_buf->status_type) {
 	case FSF_STATUS_READ_PORT_CLOSED:
@@ -915,7 +915,7 @@ static void zfcp_fsf_send_ct_handler(str
 
 	switch (header->fsf_status) {
         case FSF_GOOD:
-		zfcp_dbf_san_res("fsscth1", req);
+		zfcp_dbf_san_res("fsscth2", req);
 		ct->status = 0;
 		break;
         case FSF_SERVICE_CLASS_NOT_SUPPORTED:
#3 lore raw

PATCH 3/8 zfcp: Bounds checking for deferred error trace

In reply to Steffen Maier

From: Steffen Maier <[email protected]>

The pl vector has scount elements, i.e. pl[scount-1] is the last valid element. For maximum sized requests, payload->counter == scount after the last loop iteration. Therefore, do bounds checking first (with boolean shortcut) to not access the invalid element pl[scount].

Do not trust the maximum sbale->scount value from the HBA but ensure we won't access the pl vector out of our allocated bounds. While at it, clean up scoping and prevent unnecessary memset.

Minor fix for 86a9668a8d29ea711613e1cb37efa68e7c4db564 "[SCSI] zfcp: support for hardware data router"

---
 drivers/s390/scsi/zfcp_dbf.c  |    2 +-
 drivers/s390/scsi/zfcp_qdio.c |   16 ++++++++++------
 2 files changed, 11 insertions(+), 7 deletions(-)
drivers/s390/scsi/zfcp_dbf.c +1 -1
@@ -191,7 +191,7 @@ void zfcp_dbf_hba_def_err(struct zfcp_ad
 	length = min((u16)sizeof(struct qdio_buffer),
 		     (u16)ZFCP_DBF_PAY_MAX_REC);
 
-	while ((char *)pl[payload->counter] && payload->counter < scount) {
+	while (payload->counter < scount && (char *)pl[payload->counter]) {
 		memcpy(payload->data, (char *)pl[payload->counter], length);
 		debug_event(dbf->pay, 1, payload, zfcp_dbf_plen(length));
 		payload->counter++;
drivers/s390/scsi/zfcp_qdio.c +10 -6
@@ -102,18 +102,22 @@ static void zfcp_qdio_int_resp(struct cc
 {
 	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
 	struct zfcp_adapter *adapter = qdio->adapter;
-	struct qdio_buffer_element *sbale;
 	int sbal_no, sbal_idx;
-	void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
-	u64 req_id;
-	u8 scount;
 
 	if (unlikely(qdio_err)) {
-		memset(pl, 0, ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
 		if (zfcp_adapter_multi_buffer_active(adapter)) {
+			void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
+			struct qdio_buffer_element *sbale;
+			u64 req_id;
+			u8 scount;
+
+			memset(pl, 0,
+			       ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
 			sbale = qdio->res_q[idx]->element;
 			req_id = (u64) sbale->addr;
-			scount = sbale->scount + 1; /* incl. signaling SBAL */
+			scount = min(sbale->scount + 1,
+				     ZFCP_QDIO_MAX_SBALS_PER_REQ + 1);
+				     /* incl. signaling SBAL */
 
 			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
 				sbal_idx = (idx + sbal_no) %
#4 lore raw

PATCH 4/8 zfcp: Do not wakeup while suspended

In reply to Steffen Maier

From: Steffen Maier <[email protected]>

If the mapping of FCP device bus ID and corresponding subchannel is modified while the Linux image is suspended, the resume of FCP devices can fail. During resume, zfcp gets callbacks from cio regarding the modified subchannels but they can be arbitrarily mixed with the restore/resume callback. Since the cio callbacks would trigger adapter recovery, zfcp could wakeup before the resume callback. Therefore, ignore the cio callbacks regarding subchannels while being suspended. We can safely do so, since zfcp does not deal itself with subchannels. For problem determination purposes, we still trace the ignored callback events.

The following kernel messages could be seen on resume:

kernel: <WWPN>: parent <FCP device bus ID> should not be sleeping

As part of adapter reopen recovery, zfcp performs auto port scanning which can erroneously try to register new remote ports with scsi_transport_fc and the device core code complains about the parent (adapter) still sleeping.

kernel: zfcp.3dff9c: <FCP device bus ID>:\
Setting up the QDIO connection to the FCP adapter failed
<last kernel message repeated 3 more times>
kernel: zfcp.574d43: <FCP device bus ID>:\
ERP cannot recover an error on the FCP device

In such cases, the adapter gave up recovery and remained blocked along with its child objects: remote ports and LUNs/scsi devices. Even the adapter shutdown as part of giving up recovery failed because the ccw device state remained disconnected. Later, the corresponding remote ports ran into dev_loss_tmo. As a result, the LUNs were erroneously not available again after resume.

Even a manually triggered adapter recovery (e.g. sysfs attribute failed, or device offline/online via sysfs) could not recover the adapter due to the remaining disconnected state of the corresponding ccw device.

---
 drivers/s390/scsi/zfcp_ccw.c |   73 +++++++++++++++++++++++++++++++++++++------
 drivers/s390/scsi/zfcp_dbf.c |   20 +++++++++++
 drivers/s390/scsi/zfcp_dbf.h |    1 
 drivers/s390/scsi/zfcp_def.h |    1 
 drivers/s390/scsi/zfcp_ext.h |    1 
 5 files changed, 86 insertions(+), 10 deletions(-)
drivers/s390/scsi/zfcp_ccw.c +63 -10
@@ -39,17 +39,23 @@ void zfcp_ccw_adapter_put(struct zfcp_ad
 	spin_unlock_irqrestore(&zfcp_ccw_adapter_ref_lock, flags);
 }
 
-static int zfcp_ccw_activate(struct ccw_device *cdev)
-
+/**
+ * zfcp_ccw_activate - activate adapter and wait for it to finish
+ * @cdev: pointer to belonging ccw device
+ * @clear: Status flags to clear.
+ * @tag: s390dbf trace record tag
+ */
+static int zfcp_ccw_activate(struct ccw_device *cdev, int clear, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
+	zfcp_erp_clear_adapter_status(adapter, clear);
 	zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
 	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
-				"ccresu2");
+				tag);
 	zfcp_erp_wait(adapter);
 	flush_work(&adapter->scan_work);
 
@@ -164,26 +170,29 @@ static int zfcp_ccw_set_online(struct cc
 	BUG_ON(!zfcp_reqlist_isempty(adapter->req_list));
 	adapter->req_no = 0;
 
-	zfcp_ccw_activate(cdev);
+	zfcp_ccw_activate(cdev, 0, "ccsonl1");
 	zfcp_ccw_adapter_put(adapter);
 	return 0;
 }
 
 /**
- * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * zfcp_ccw_offline_sync - shut down adapter and wait for it to finish
  * @cdev: pointer to belonging ccw device
+ * @set: Status flags to set.
+ * @tag: s390dbf trace record tag
  *
  * This function gets called by the common i/o layer and sets an adapter
  * into state offline.
  */
-static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+static int zfcp_ccw_offline_sync(struct ccw_device *cdev, int set, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
-	zfcp_erp_adapter_shutdown(adapter, 0, "ccsoff1");
+	zfcp_erp_set_adapter_status(adapter, set);
+	zfcp_erp_adapter_shutdown(adapter, 0, tag);
 	zfcp_erp_wait(adapter);
 
 	zfcp_ccw_adapter_put(adapter);
@@ -191,6 +200,18 @@ static int zfcp_ccw_set_offline(struct c
 }
 
 /**
+ * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * @cdev: pointer to belonging ccw device
+ *
+ * This function gets called by the common i/o layer and sets an adapter
+ * into state offline.
+ */
+static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+{
+	return zfcp_ccw_offline_sync(cdev, 0, "ccsoff1");
+}
+
+/**
  * zfcp_ccw_notify - ccw notify function
  * @cdev: pointer to belonging ccw device
  * @event: indicates if adapter was detached or attached
@@ -207,6 +228,11 @@ static int zfcp_ccw_notify(struct ccw_de
 
 	switch (event) {
 	case CIO_GONE:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccnigo1", adapter);
+			break;
+		}
 		dev_warn(&cdev->dev, "The FCP device has been detached\n");
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti1");
 		break;
@@ -216,6 +242,11 @@ static int zfcp_ccw_notify(struct ccw_de
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti2");
 		break;
 	case CIO_OPER:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccniop1", adapter);
+			break;
+		}
 		dev_info(&cdev->dev, "The FCP device is operational again\n");
 		zfcp_erp_set_adapter_status(adapter,
 					    ZFCP_STATUS_COMMON_RUNNING);
@@ -251,6 +282,28 @@ static void zfcp_ccw_shutdown(struct ccw
 	zfcp_ccw_adapter_put(adapter);
 }
 
+static int zfcp_ccw_suspend(struct ccw_device *cdev)
+{
+	zfcp_ccw_offline_sync(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccsusp1");
+	return 0;
+}
+
+static int zfcp_ccw_thaw(struct ccw_device *cdev)
+{
+	/* trace records for thaw and final shutdown during suspend
+	   can only be found in system dump until the end of suspend
+	   but not after resume because it's based on the memory image
+	   right after the very first suspend (freeze) callback */
+	zfcp_ccw_activate(cdev, 0, "ccthaw1");
+	return 0;
+}
+
+static int zfcp_ccw_resume(struct ccw_device *cdev)
+{
+	zfcp_ccw_activate(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccresu1");
+	return 0;
+}
+
 struct ccw_driver zfcp_ccw_driver = {
 	.driver = {
 		.owner	= THIS_MODULE,
@@ -263,7 +316,7 @@ struct ccw_driver zfcp_ccw_driver = {
 	.set_offline = zfcp_ccw_set_offline,
 	.notify      = zfcp_ccw_notify,
 	.shutdown    = zfcp_ccw_shutdown,
-	.freeze      = zfcp_ccw_set_offline,
-	.thaw	     = zfcp_ccw_activate,
-	.restore     = zfcp_ccw_activate,
+	.freeze      = zfcp_ccw_suspend,
+	.thaw	     = zfcp_ccw_thaw,
+	.restore     = zfcp_ccw_resume,
 };
drivers/s390/scsi/zfcp_dbf.c +20 -0
@@ -200,6 +200,26 @@ void zfcp_dbf_hba_def_err(struct zfcp_ad
 	spin_unlock_irqrestore(&dbf->pay_lock, flags);
 }
 
+/**
+ * zfcp_dbf_hba_basic - trace event for basic adapter events
+ * @adapter: pointer to struct zfcp_adapter
+ */
+void zfcp_dbf_hba_basic(char *tag, struct zfcp_adapter *adapter)
+{
+	struct zfcp_dbf *dbf = adapter->dbf;
+	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dbf->hba_lock, flags);
+	memset(rec, 0, sizeof(*rec));
+
+	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
+	rec->id = ZFCP_DBF_HBA_BASIC;
+
+	debug_event(dbf->hba, 1, rec, sizeof(*rec));
+	spin_unlock_irqrestore(&dbf->hba_lock, flags);
+}
+
 static void zfcp_dbf_set_common(struct zfcp_dbf_rec *rec,
 				struct zfcp_adapter *adapter,
 				struct zfcp_port *port,
drivers/s390/scsi/zfcp_dbf.h +1 -0
@@ -154,6 +154,7 @@ enum zfcp_dbf_hba_id {
 	ZFCP_DBF_HBA_RES	= 1,
 	ZFCP_DBF_HBA_USS	= 2,
 	ZFCP_DBF_HBA_BIT	= 3,
+	ZFCP_DBF_HBA_BASIC	= 4,
 };
 
 /**
drivers/s390/scsi/zfcp_def.h +1 -0
@@ -77,6 +77,7 @@ struct zfcp_reqlist;
 #define ZFCP_STATUS_ADAPTER_SIOSL_ISSUED	0x00000004
 #define ZFCP_STATUS_ADAPTER_XCONFIG_OK		0x00000008
 #define ZFCP_STATUS_ADAPTER_HOST_CON_INIT	0x00000010
+#define ZFCP_STATUS_ADAPTER_SUSPENDED		0x00000040
 #define ZFCP_STATUS_ADAPTER_ERP_PENDING		0x00000100
 #define ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED	0x00000200
 #define ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED	0x00000400
drivers/s390/scsi/zfcp_ext.h +1 -0
@@ -54,6 +54,7 @@ extern void zfcp_dbf_hba_fsf_res(char *,
 extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_berr(struct zfcp_dbf *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_def_err(struct zfcp_adapter *, u64, u16, void **);
+extern void zfcp_dbf_hba_basic(char *, struct zfcp_adapter *);
 extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32);
 extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *);
#5 lore raw

PATCH 5/8 zfcp: remove invalid reference to list iterator variable

In reply to Steffen Maier

From: Julia Lawall <[email protected]>

If list_for_each_entry, etc complete a traversal of the list, the iterator variable ends up pointing to an address at an offset from the list head, and not a meaningful structure. Thus this value should not be used after the end of the iterator. Replace port->adapter->scsi_host by adapter->scsi_host.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Oversight in upsteam commit of v2.6.37 a1ca48319a9aa1c5b57ce142f538e76050bb8972
"[SCSI] zfcp: Move ACL/CFDC code to zfcp_cfdc.c" which merged the content of zfcp_erp_port_access_changed().

---
 drivers/s390/scsi/zfcp_cfdc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/s390/scsi/zfcp_cfdc.c +1 -1
@@ -293,7 +293,7 @@ void zfcp_cfdc_adapter_access_changed(st
 	}
 	read_unlock_irqrestore(&adapter->port_list_lock, flags);
 
-	shost_for_each_device(sdev, port->adapter->scsi_host) {
+	shost_for_each_device(sdev, adapter->scsi_host) {
 		zfcp_sdev = sdev_to_zfcp(sdev);
 		status = atomic_read(&zfcp_sdev->status);
 		if ((status & ZFCP_STATUS_COMMON_ACCESS_DENIED) ||
#6 lore raw

PATCH 6/8 zfcp: restore refcount check on port_remove

In reply to Steffen Maier

From: Steffen Maier <[email protected]>

Upstream commit f3450c7b917201bb49d67032e9f60d5125675d6a "[SCSI] zfcp: Replace local reference counting with common kref" accidentally dropped a reference count check before tearing down zfcp_ports that are potentially in use by zfcp_units. Even remote ports in use can be removed causing unreachable garbage objects zfcp_ports with zfcp_units. Thus units won't come back even after a manual port_rescan. The kref of zfcp_port->dev.kobj is already used by the driver core. We cannot re-use it to track the number of zfcp_units. Re-introduce our own counter for units per port
and check on port_remove.

---
 drivers/s390/scsi/zfcp_aux.c   |    1 +
 drivers/s390/scsi/zfcp_def.h   |    1 +
 drivers/s390/scsi/zfcp_ext.h   |    1 +
 drivers/s390/scsi/zfcp_sysfs.c |   18 ++++++++++++++++--
 drivers/s390/scsi/zfcp_unit.c  |   36 ++++++++++++++++++++++++++----------
 5 files changed, 45 insertions(+), 12 deletions(-)
drivers/s390/scsi/zfcp_aux.c +1 -0
@@ -519,6 +519,7 @@ struct zfcp_port *zfcp_port_enqueue(stru
 
 	rwlock_init(&port->unit_list_lock);
 	INIT_LIST_HEAD(&port->unit_list);
+	atomic_set(&port->units, 0);
 
 	INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
 	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
drivers/s390/scsi/zfcp_def.h +1 -0
@@ -205,6 +205,7 @@ struct zfcp_port {
 	struct zfcp_adapter    *adapter;       /* adapter used to access port */
 	struct list_head	unit_list;	/* head of logical unit list */
 	rwlock_t		unit_list_lock; /* unit list lock */
+	atomic_t		units;	       /* zfcp_unit count */
 	atomic_t	       status;	       /* status of this remote port */
 	u64		       wwnn;	       /* WWNN if known */
 	u64		       wwpn;	       /* WWPN */
drivers/s390/scsi/zfcp_ext.h +1 -0
@@ -159,6 +159,7 @@ extern void zfcp_scsi_dif_sense_error(st
 extern struct attribute_group zfcp_sysfs_unit_attrs;
 extern struct attribute_group zfcp_sysfs_adapter_attrs;
 extern struct attribute_group zfcp_sysfs_port_attrs;
+extern struct mutex zfcp_sysfs_port_units_mutex;
 extern struct device_attribute *zfcp_sysfs_sdev_attrs[];
 extern struct device_attribute *zfcp_sysfs_shost_attrs[];
 
drivers/s390/scsi/zfcp_sysfs.c +16 -2
@@ -227,6 +227,8 @@ static ssize_t zfcp_sysfs_port_rescan_st
 static ZFCP_DEV_ATTR(adapter, port_rescan, S_IWUSR, NULL,
 		     zfcp_sysfs_port_rescan_store);
 
+DEFINE_MUTEX(zfcp_sysfs_port_units_mutex);
+
 static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t count)
@@ -249,6 +251,16 @@ static ssize_t zfcp_sysfs_port_remove_st
 	else
 		retval = 0;
 
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) > 0) {
+		retval = -EBUSY;
+		mutex_unlock(&zfcp_sysfs_port_units_mutex);
+		goto out;
+	}
+	/* port is about to be removed, so no more unit_add */
+	atomic_set(&port->units, -1);
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+
 	write_lock_irq(&adapter->port_list_lock);
 	list_del(&port->list);
 	write_unlock_irq(&adapter->port_list_lock);
@@ -289,12 +301,14 @@ static ssize_t zfcp_sysfs_unit_add_store
 {
 	struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
 	u64 fcp_lun;
+	int retval;
 
 	if (strict_strtoull(buf, 0, (unsigned long long *) &fcp_lun))
 		return -EINVAL;
 
-	if (zfcp_unit_add(port, fcp_lun))
-		return -EINVAL;
+	retval = zfcp_unit_add(port, fcp_lun);
+	if (retval)
+		return retval;
 
 	return count;
 }
drivers/s390/scsi/zfcp_unit.c +26 -10
@@ -104,7 +104,7 @@ static void zfcp_unit_release(struct dev
 {
 	struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
 
-	put_device(&unit->port->dev);
+	atomic_dec(&unit->port->units);
 	kfree(unit);
 }
 
@@ -119,16 +119,27 @@ static void zfcp_unit_release(struct dev
 int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 {
 	struct zfcp_unit *unit;
+	int retval = 0;
+
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) == -1) {
+		/* port is already gone */
+		retval = -ENODEV;
+		goto out;
+	}
 
 	unit = zfcp_unit_find(port, fcp_lun);
 	if (unit) {
 		put_device(&unit->dev);
-		return -EEXIST;
+		retval = -EEXIST;
+		goto out;
 	}
 
 	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
-	if (!unit)
-		return -ENOMEM;
+	if (!unit) {
+		retval = -ENOMEM;
+		goto out;
+	}
 
 	unit->port = port;
 	unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port
 	if (dev_set_name(&unit->dev, "0x%016llx",
 			 (unsigned long long) fcp_lun)) {
 		kfree(unit);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
-	get_device(&port->dev);
-
 	if (device_register(&unit->dev)) {
 		put_device(&unit->dev);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
 	if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
 		device_unregister(&unit->dev);
-		return -EINVAL;
+		retval = -EINVAL;
+		goto out;
 	}
 
+	atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
+
 	write_lock_irq(&port->unit_list_lock);
 	list_add_tail(&unit->list, &port->unit_list);
 	write_unlock_irq(&port->unit_list_lock);
 
 	zfcp_unit_scsi_scan(unit);
 
-	return 0;
+out:
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+	return retval;
 }
 
 /**
#7 lore raw

PATCH 7/8 zfcp: No automatic port_rescan on events

In reply to Steffen Maier

From: Steffen Maier <[email protected]>

In FC fabrics with large zones, the automatic port_rescan on incoming ELS and any adapter recovery can cause quite some traffic at the very same time, especially if lots of Linux images share an HBA, which is common on s390. This can cause trouble and failures. Fix this by making such port rescans dependent on a user configurable module parameter.

The following unconditional automatic port rescans remain as is:
On setting an adapter online and
on manual user-triggered writes to the sysfs attribute port_rescan.

---
 drivers/s390/scsi/zfcp_ccw.c |    7 ++++++-
 drivers/s390/scsi/zfcp_erp.c |    2 +-
 drivers/s390/scsi/zfcp_ext.h |    2 ++
 drivers/s390/scsi/zfcp_fc.c  |   23 ++++++++++++++++++++++-
 drivers/s390/scsi/zfcp_fsf.c |    2 +-
 5 files changed, 32 insertions(+), 4 deletions(-)
drivers/s390/scsi/zfcp_ccw.c +6 -1
@@ -57,7 +57,7 @@ static int zfcp_ccw_activate(struct ccw_
 	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
 				tag);
 	zfcp_erp_wait(adapter);
-	flush_work(&adapter->scan_work);
+	flush_work(&adapter->scan_work); /* ok to call even if nothing queued */
 
 	zfcp_ccw_adapter_put(adapter);
 
@@ -171,6 +171,11 @@ static int zfcp_ccw_set_online(struct cc
 	adapter->req_no = 0;
 
 	zfcp_ccw_activate(cdev, 0, "ccsonl1");
+	/* scan for remote ports
+	   either at the end of any successful adapter recovery
+	   or only after the adapter recovery for setting a device online */
+	zfcp_fc_inverse_conditional_port_scan(adapter);
+	flush_work(&adapter->scan_work); /* ok to call even if nothing queued */
 	zfcp_ccw_adapter_put(adapter);
 	return 0;
 }
drivers/s390/scsi/zfcp_erp.c +1 -1
@@ -1230,7 +1230,7 @@ static void zfcp_erp_action_cleanup(stru
 	case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
 		if (result == ZFCP_ERP_SUCCEEDED) {
 			register_service_level(&adapter->service_level);
-			queue_work(adapter->work_queue, &adapter->scan_work);
+			zfcp_fc_conditional_port_scan(adapter);
 			queue_work(adapter->work_queue, &adapter->ns_up_work);
 		} else
 			unregister_service_level(&adapter->service_level);
drivers/s390/scsi/zfcp_ext.h +2 -0
@@ -99,6 +99,8 @@ extern void zfcp_fc_gs_destroy(struct zf
 extern int zfcp_fc_exec_bsg_job(struct fc_bsg_job *);
 extern int zfcp_fc_timeout_bsg_job(struct fc_bsg_job *);
 extern void zfcp_fc_sym_name_update(struct work_struct *);
+extern void zfcp_fc_conditional_port_scan(struct zfcp_adapter *);
+extern void zfcp_fc_inverse_conditional_port_scan(struct zfcp_adapter *);
 
 /* zfcp_fsf.c */
 extern struct kmem_cache *zfcp_fsf_qtcb_cache;
drivers/s390/scsi/zfcp_fc.c +22 -1
@@ -26,6 +26,27 @@ static u32 zfcp_fc_rscn_range_mask[] = {
 	[ELS_ADDR_FMT_FAB]		= 0x000000,
 };
 
+static bool no_auto_port_rescan;
+module_param_named(no_auto_port_rescan, no_auto_port_rescan, bool, 0600);
+MODULE_PARM_DESC(no_auto_port_rescan,
+		 "no automatic port_rescan (default off)");
+
+void zfcp_fc_conditional_port_scan(struct zfcp_adapter *adapter)
+{
+	if (no_auto_port_rescan)
+		return;
+
+	queue_work(adapter->work_queue, &adapter->scan_work);
+}
+
+void zfcp_fc_inverse_conditional_port_scan(struct zfcp_adapter *adapter)
+{
+	if (!no_auto_port_rescan)
+		return;
+
+	queue_work(adapter->work_queue, &adapter->scan_work);
+}
+
 /**
  * zfcp_fc_post_event - post event to userspace via fc_transport
  * @work: work struct with enqueued events
@@ -206,7 +227,7 @@ static void zfcp_fc_incoming_rscn(struct
 		zfcp_fc_enqueue_event(fsf_req->adapter, FCH_EVT_RSCN,
 				      *(u32 *)page);
 	}
-	queue_work(fsf_req->adapter->work_queue, &fsf_req->adapter->scan_work);
+	zfcp_fc_conditional_port_scan(fsf_req->adapter);
 }
 
 static void zfcp_fc_incoming_wwpn(struct zfcp_fsf_req *req, u64 wwpn)
drivers/s390/scsi/zfcp_fsf.c +1 -1
@@ -257,7 +257,7 @@ static void zfcp_fsf_status_read_handler
 		if (sr_buf->status_subtype & FSF_STATUS_READ_SUB_ACT_UPDATED)
 			zfcp_cfdc_adapter_access_changed(adapter);
 		if (sr_buf->status_subtype & FSF_STATUS_READ_SUB_INCOMING_ELS)
-			queue_work(adapter->work_queue, &adapter->scan_work);
+			zfcp_fc_conditional_port_scan(adapter);
 		break;
 	case FSF_STATUS_READ_CFDC_UPDATED:
 		zfcp_cfdc_adapter_access_changed(adapter);
#8 lore raw

PATCH 8/8 zfcp: only access zfcp_scsi_dev for valid scsi_device

In reply to Steffen Maier

From: Martin Peschke <[email protected]>

__scsi_remove_device (e.g. due to dev_loss_tmo) calls zfcp_scsi_slave_destroy which in turn sends a close LUN FSF request to the adapter. After 30 seconds without response, zfcp_erp_timeout_handler kicks the ERP thread failing the close LUN ERP action. zfcp_erp_wait in zfcp_erp_lun_shutdown_wait and thus zfcp_scsi_slave_destroy returns and then scsi_device is no longer valid. Sometime later the response to the close LUN FSF request may finally come in. However, commit b62a8d9b45b971a67a0f8413338c230e3117dff5
"[SCSI] zfcp: Use SCSI device data zfcp_scsi_dev instead of zfcp_unit" introduced a number of attempts to unconditionally access struct zfcp_scsi_dev through struct scsi_device causing a use-after-free. This leads to an Oops due to kernel page fault in one of:
zfcp_fsf_abort_fcp_command_handler, zfcp_fsf_open_lun_handler, zfcp_fsf_close_lun_handler, zfcp_fsf_req_trace, zfcp_fsf_fcp_handler_common.
Move dereferencing of zfcp private data zfcp_scsi_dev allocated in scsi_device via scsi_transport_reserve_device after the check for potentially aborted FSF request and thus no longer valid scsi_device. Only then assign sdev_to_zfcp(sdev) to the local auto variable struct zfcp_scsi_dev *zfcp_sdev.

---
 drivers/s390/scsi/zfcp_fsf.c |   19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)
drivers/s390/scsi/zfcp_fsf.c +14 -5
@@ -801,12 +801,14 @@ out:
 static void zfcp_fsf_abort_fcp_command_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	union fsf_status_qual *fsq = &req->qtcb->header.fsf_status_qual;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		if (fsq->word[0] == fsq->word[1]) {
@@ -1769,13 +1771,15 @@ static void zfcp_fsf_open_lun_handler(st
 {
 	struct zfcp_adapter *adapter = req->adapter;
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 	struct fsf_qtcb_bottom_support *bottom = &req->qtcb->bottom.support;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED |
 			  ZFCP_STATUS_COMMON_ACCESS_BOXED |
 			  ZFCP_STATUS_LUN_SHARED |
@@ -1886,11 +1890,13 @@ out:
 static void zfcp_fsf_close_lun_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		zfcp_erp_adapter_reopen(zfcp_sdev->port->adapter, 0, "fscuh_1");
@@ -1980,7 +1986,7 @@ static void zfcp_fsf_req_trace(struct zf
 {
 	struct fsf_qual_latency_info *lat_in;
 	struct latency_cont *lat = NULL;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scsi->device);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct zfcp_blk_drv_data blktrc;
 	int ticks = req->adapter->timer_ticks;
 
@@ -1995,6 +2001,7 @@ static void zfcp_fsf_req_trace(struct zf
 
 	if (req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA &&
 	    !(req->status & ZFCP_STATUS_FSFREQ_ERROR)) {
+		zfcp_sdev = sdev_to_zfcp(scsi->device);
 		blktrc.flags |= ZFCP_BLK_LAT_VALID;
 		blktrc.channel_lat = lat_in->channel_lat * ticks;
 		blktrc.fabric_lat = lat_in->fabric_lat * ticks;
@@ -2032,12 +2039,14 @@ static void zfcp_fsf_fcp_handler_common(
 {
 	struct scsi_cmnd *scmnd = req->data;
 	struct scsi_device *sdev = scmnd->device;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 
 	if (unlikely(req->status & ZFCP_STATUS_FSFREQ_ERROR))
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (header->fsf_status) {
 	case FSF_HANDLE_MISMATCH:
 	case FSF_PORT_HANDLE_NOT_VALID: