s390/dasd: enhance CUIR scope detection

This patch adds an enhanced detection for control unit initiated
reconfiguration request scope.
The first approach assumed the scope of the reconfiguration request
to be restricted to the path on which the message was received.
The enhanced approach determines the full scope of the reconfiguration
request by evaluating additional path and device selection information
contained in the reconfiguration message.

Reviewed-by: Peter Oberparleiter <[e-mail]>
Reviewed-by: Sebastian Ott <[e-mail]>
Signed-off-by: Stefan Haberland <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/block/dasd_eckd.c

···
 {
 	void *conf_data;
 	int conf_len, conf_data_saved;
-	int rc, path_err;
+	int rc, path_err, pos;
 	__u8 lpm, opm;
 	struct dasd_eckd_private *private, path_private;
 	struct dasd_path *path_data;
···
 			path_data->opm |= lpm;
 			continue;	/* no error */
 		}
+		/* translate path mask to position in mask */
+		pos = 8 - ffs(lpm);
+		kfree(private->path_conf_data[pos]);
+		if ((__u8 *)private->path_conf_data[pos] ==
+		    private->conf_data) {
+			private->conf_data = NULL;
+			private->conf_len = 0;
+			conf_data_saved = 0;
+		}
+		private->path_conf_data[pos] =
+			(struct dasd_conf_data *) conf_data;
 		/* save first valid configuration data */
 		if (!conf_data_saved) {
 			kfree(private->conf_data);
···
 				kfree(conf_data);
 				continue;
 			}
-
 			if (dasd_eckd_compare_path_uid(
 				    device, &path_private)) {
 				uid = &path_private.uid;
···
 		path_data->cablepm &= ~lpm;
 		path_data->hpfpm &= ~lpm;
 		path_data->cuirpm &= ~lpm;
-
-		if (conf_data != private->conf_data)
-			kfree(conf_data);
 	}
 
 	return path_err;
···
 static void dasd_eckd_uncheck_device(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private;
+	int i;
 
 	private = (struct dasd_eckd_private *) device->private;
 	dasd_alias_disconnect_device_from_lcu(device);
···
 	private->vdsneq = NULL;
 	private->gneq = NULL;
 	private->conf_len = 0;
+	for (i = 0; i < 8; i++) {
+		kfree(private->path_conf_data[i]);
+		if ((__u8 *)private->path_conf_data[i] ==
+		    private->conf_data) {
+			private->conf_data = NULL;
+			private->conf_len = 0;
+		}
+		private->path_conf_data[i] = NULL;
+	}
 	kfree(private->conf_data);
 	private->conf_data = NULL;
 }
···
 	cqr->startdev = device;
 	cqr->memdev = device;
 	cqr->block = NULL;
-	cqr->retries = 256;
 	cqr->expires = 10 * HZ;
-
-	/* we need to check for messages on exactly this path */
 	set_bit(DASD_CQR_VERIFY_PATH, &cqr->flags);
-	cqr->lpm = lpum;
+	/* dasd_sleep_on_immediatly does not do complex error
+	 * recovery so clear erp flag and set retry counter to
+	 * do basic erp */
+	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+	cqr->retries = 256;
 
 	/* Prepare for Read Subsystem Data */
 	prssdp = (struct dasd_psf_prssd_data *) cqr->data;
···
 	psf_cuir->message_id = message_id;
 	psf_cuir->cssid = sch_id.cssid;
 	psf_cuir->ssid = sch_id.ssid;
-
 	ccw = cqr->cpaddr;
 	ccw->cmd_code = DASD_ECKD_CCW_PSF;
 	ccw->cda = (__u32)(addr_t)psf_cuir;
+	ccw->flags = CCW_FLAG_SLI;
 	ccw->count = sizeof(struct dasd_psf_cuir_response);
 
 	cqr->startdev = device;
···
 	cqr->expires = 10*HZ;
 	cqr->buildclk = get_tod_clock();
 	cqr->status = DASD_CQR_FILLED;
+	set_bit(DASD_CQR_VERIFY_PATH, &cqr->flags);
 
 	rc = dasd_sleep_on(cqr);
 
···
 	return rc;
 }
 
-static int dasd_eckd_cuir_change_state(struct dasd_device *device, __u8 lpum)
+/*
+ * return configuration data that is referenced by record selector
+ * if a record selector is specified or per default return the
+ * conf_data pointer for the path specified by lpum
+ */
+static struct dasd_conf_data *dasd_eckd_get_ref_conf(struct dasd_device *device,
+						     __u8 lpum,
+						     struct dasd_cuir_message *cuir)
 {
-	unsigned long flags;
-	__u8 tbcpm;
+	struct dasd_eckd_private *private;
+	struct dasd_conf_data *conf_data;
+	int path, pos;
 
-	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
-	tbcpm = device->path_data.opm & ~lpum;
-	if (tbcpm) {
-		device->path_data.opm = tbcpm;
-		device->path_data.cuirpm |= lpum;
+	private = (struct dasd_eckd_private *) device->private;
+	if (cuir->record_selector == 0)
+		goto out;
+	for (path = 0x80, pos = 0; path; path >>= 1, pos++) {
+		conf_data = private->path_conf_data[pos];
+		if (conf_data->gneq.record_selector ==
+		    cuir->record_selector)
+			return conf_data;
 	}
-	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
-	return tbcpm ? 0 : PSF_CUIR_LAST_PATH;
+out:
+	return private->path_conf_data[8 - ffs(lpum)];
 }
 
 /*
- * walk through all devices and quiesce them
- * if it is the last path return error
+ * This function determines the scope of a reconfiguration request by
+ * analysing the path and device selection data provided in the CUIR request.
+ * Returns a path mask containing CUIR affected paths for the give device.
+ *
+ * If the CUIR request does not contain the required information return the
+ * path mask of the path the attention message for the CUIR request was reveived
+ * on.
+ */
+static int dasd_eckd_cuir_scope(struct dasd_device *device, __u8 lpum,
+				struct dasd_cuir_message *cuir)
+{
+	struct dasd_conf_data *ref_conf_data;
+	unsigned long bitmask = 0, mask = 0;
+	struct dasd_eckd_private *private;
+	struct dasd_conf_data *conf_data;
+	unsigned int pos, path;
+	char *ref_gneq, *gneq;
+	char *ref_ned, *ned;
+	int tbcpm = 0;
+
+	/* if CUIR request does not specify the scope use the path
+	   the attention message was presented on */
+	if (!cuir->ned_map ||
+	    !(cuir->neq_map[0] | cuir->neq_map[1] | cuir->neq_map[2]))
+		return lpum;
+
+	private = (struct dasd_eckd_private *) device->private;
+	/* get reference conf data */
+	ref_conf_data = dasd_eckd_get_ref_conf(device, lpum, cuir);
+	/* reference ned is determined by ned_map field */
+	pos = 8 - ffs(cuir->ned_map);
+	ref_ned = (char *)&ref_conf_data->neds[pos];
+	ref_gneq = (char *)&ref_conf_data->gneq;
+	/* transfer 24 bit neq_map to mask */
+	mask = cuir->neq_map[2];
+	mask |= cuir->neq_map[1] << 8;
+	mask |= cuir->neq_map[0] << 16;
+
+	for (path = 0x80; path; path >>= 1) {
+		/* initialise data per path */
+		bitmask = mask;
+		pos = 8 - ffs(path);
+		conf_data = private->path_conf_data[pos];
+		pos = 8 - ffs(cuir->ned_map);
+		ned = (char *) &conf_data->neds[pos];
+		/* compare reference ned and per path ned */
+		if (memcmp(ref_ned, ned, sizeof(*ned)) != 0)
+			continue;
+		gneq = (char *)&conf_data->gneq;
+		/* compare reference gneq and per_path gneq under
+		   24 bit mask where mask bit 0 equals byte 7 of
+		   the gneq and mask bit 24 equals byte 31 */
+		while (bitmask) {
+			pos = ffs(bitmask) - 1;
+			if (memcmp(&ref_gneq[31 - pos], &gneq[31 - pos], 1)
+			    != 0)
+				break;
+			clear_bit(pos, &bitmask);
+		}
+		if (bitmask)
+			continue;
+		/* device and path match the reference values
+		   add path to CUIR scope */
+		tbcpm |= path;
+	}
+	return tbcpm;
+}
+
+static void dasd_eckd_cuir_notify_user(struct dasd_device *device,
+				       unsigned long paths,
+				       struct subchannel_id sch_id, int action)
+{
+	struct channel_path_desc *desc;
+	int pos;
+
+	while (paths) {
+		/* get position of bit in mask */
+		pos = ffs(paths) - 1;
+		/* get channel path descriptor from this position */
+		desc = ccw_device_get_chp_desc(device->cdev, 7 - pos);
+		if (action == CUIR_QUIESCE)
+			pr_warn("Service on the storage server caused path "
+				"%x.%02x to go offline", sch_id.cssid,
+				desc ? desc->chpid : 0);
+		else if (action == CUIR_RESUME)
+			pr_info("Path %x.%02x is back online after service "
+				"on the storage server", sch_id.cssid,
+				desc ? desc->chpid : 0);
+		kfree(desc);
+		clear_bit(pos, &paths);
+	}
+}
+
+static int dasd_eckd_cuir_remove_path(struct dasd_device *device, __u8 lpum,
+				      struct dasd_cuir_message *cuir)
+{
+	unsigned long tbcpm;
+
+	tbcpm = dasd_eckd_cuir_scope(device, lpum, cuir);
+	/* nothing to do if path is not in use */
+	if (!(device->path_data.opm & tbcpm))
+		return 0;
+	if (!(device->path_data.opm & ~tbcpm)) {
+		/* no path would be left if the CUIR action is taken
+		   return error */
+		return -EINVAL;
+	}
+	/* remove device from operational path mask */
+	device->path_data.opm &= ~tbcpm;
+	device->path_data.cuirpm |= tbcpm;
+	return tbcpm;
+}
+
+/*
+ * walk through all devices and build a path mask to quiesce them
+ * return an error if the last path to a device would be removed
  *
  * if only part of the devices are quiesced and an error
  * occurs no onlining necessary, the storage server will
  * notify the already set offline devices again
  */
 static int dasd_eckd_cuir_quiesce(struct dasd_device *device, __u8 lpum,
-				 struct channel_path_desc *desc,
-				 struct subchannel_id sch_id)
+				  struct subchannel_id sch_id,
+				  struct dasd_cuir_message *cuir)
 {
 	struct alias_pav_group *pavgroup, *tempgroup;
 	struct dasd_eckd_private *private;
 	struct dasd_device *dev, *n;
-	int rc;
+	unsigned long paths = 0;
+	unsigned long flags;
+	int tbcpm;
 
 	private = (struct dasd_eckd_private *) device->private;
-	rc = 0;
-
 	/* active devices */
-	list_for_each_entry_safe(dev, n,
-				 &private->lcu->active_devices,
+	list_for_each_entry_safe(dev, n, &private->lcu->active_devices,
 				 alias_list) {
-		rc = dasd_eckd_cuir_change_state(dev, lpum);
-		if (rc)
-			goto out;
+		spin_lock_irqsave(get_ccwdev_lock(dev->cdev), flags);
+		tbcpm = dasd_eckd_cuir_remove_path(dev, lpum, cuir);
+		spin_unlock_irqrestore(get_ccwdev_lock(dev->cdev), flags);
+		if (tbcpm < 0)
+			goto out_err;
+		paths |= tbcpm;
 	}
-
 	/* inactive devices */
-	list_for_each_entry_safe(dev, n,
-				 &private->lcu->inactive_devices,
+	list_for_each_entry_safe(dev, n, &private->lcu->inactive_devices,
 				 alias_list) {
-		rc = dasd_eckd_cuir_change_state(dev, lpum);
-		if (rc)
-			goto out;
+		spin_lock_irqsave(get_ccwdev_lock(dev->cdev), flags);
+		tbcpm = dasd_eckd_cuir_remove_path(dev, lpum, cuir);
+		spin_unlock_irqrestore(get_ccwdev_lock(dev->cdev), flags);
+		if (tbcpm < 0)
+			goto out_err;
+		paths |= tbcpm;
 	}
-
 	/* devices in PAV groups */
 	list_for_each_entry_safe(pavgroup, tempgroup,
 				 &private->lcu->grouplist, group) {
 		list_for_each_entry_safe(dev, n, &pavgroup->baselist,
 					 alias_list) {
-			rc = dasd_eckd_cuir_change_state(dev, lpum);
-			if (rc)
-				goto out;
+			spin_lock_irqsave(get_ccwdev_lock(dev->cdev), flags);
+			tbcpm = dasd_eckd_cuir_remove_path(dev, lpum, cuir);
+			spin_unlock_irqrestore(
+				get_ccwdev_lock(dev->cdev), flags);
+			if (tbcpm < 0)
+				goto out_err;
+			paths |= tbcpm;
 		}
 		list_for_each_entry_safe(dev, n, &pavgroup->aliaslist,
 					 alias_list) {
-			rc = dasd_eckd_cuir_change_state(dev, lpum);
-			if (rc)
-				goto out;
+			spin_lock_irqsave(get_ccwdev_lock(dev->cdev), flags);
+			tbcpm = dasd_eckd_cuir_remove_path(dev, lpum, cuir);
+			spin_unlock_irqrestore(
+				get_ccwdev_lock(dev->cdev), flags);
+			if (tbcpm < 0)
+				goto out_err;
+			paths |= tbcpm;
 		}
 	}
-
-	pr_warn("Service on the storage server caused path %x.%02x to go offline",
-		sch_id.cssid, desc ? desc->chpid : 0);
-	rc = PSF_CUIR_COMPLETED;
-out:
-	return rc;
+	/* notify user about all paths affected by CUIR action */
+	dasd_eckd_cuir_notify_user(device, paths, sch_id, CUIR_QUIESCE);
+	return 0;
+out_err:
+	return tbcpm;
 }
 
 static int dasd_eckd_cuir_resume(struct dasd_device *device, __u8 lpum,
-				 struct channel_path_desc *desc,
-				 struct subchannel_id sch_id)
+				 struct subchannel_id sch_id,
+				 struct dasd_cuir_message *cuir)
 {
 	struct alias_pav_group *pavgroup, *tempgroup;
 	struct dasd_eckd_private *private;
 	struct dasd_device *dev, *n;
+	unsigned long paths = 0;
+	int tbcpm;
 
-	pr_info("Path %x.%02x is back online after service on the storage server",
-		sch_id.cssid, desc ? desc->chpid : 0);
 	private = (struct dasd_eckd_private *) device->private;
-
 	/*
 	 * the path may have been added through a generic path event before
 	 * only trigger path verification if the path is not already in use
 	 */
-
 	list_for_each_entry_safe(dev, n,
 				 &private->lcu->active_devices,
 				 alias_list) {
-		if (!(dev->path_data.opm & lpum)) {
-			dev->path_data.tbvpm |= lpum;
+		tbcpm = dasd_eckd_cuir_scope(dev, lpum, cuir);
+		paths |= tbcpm;
+		if (!(dev->path_data.opm & tbcpm)) {
+			dev->path_data.tbvpm |= tbcpm;
 			dasd_schedule_device_bh(dev);
 		}
 	}
-
 	list_for_each_entry_safe(dev, n,
 				 &private->lcu->inactive_devices,
 				 alias_list) {
-		if (!(dev->path_data.opm & lpum)) {
-			dev->path_data.tbvpm |= lpum;
+		tbcpm = dasd_eckd_cuir_scope(dev, lpum, cuir);
+		paths |= tbcpm;
+		if (!(dev->path_data.opm & tbcpm)) {
+			dev->path_data.tbvpm |= tbcpm;
 			dasd_schedule_device_bh(dev);
 		}
 	}
-
 	/* devices in PAV groups */
 	list_for_each_entry_safe(pavgroup, tempgroup,
 				 &private->lcu->grouplist,
···
 		list_for_each_entry_safe(dev, n,
 					 &pavgroup->baselist,
 					 alias_list) {
-			if (!(dev->path_data.opm & lpum)) {
-				dev->path_data.tbvpm |= lpum;
+			tbcpm = dasd_eckd_cuir_scope(dev, lpum, cuir);
+			paths |= tbcpm;
+			if (!(dev->path_data.opm & tbcpm)) {
+				dev->path_data.tbvpm |= tbcpm;
 				dasd_schedule_device_bh(dev);
 			}
 		}
 		list_for_each_entry_safe(dev, n,
 					 &pavgroup->aliaslist,
 					 alias_list) {
-			if (!(dev->path_data.opm & lpum)) {
-				dev->path_data.tbvpm |= lpum;
+			tbcpm = dasd_eckd_cuir_scope(dev, lpum, cuir);
+			paths |= tbcpm;
+			if (!(dev->path_data.opm & tbcpm)) {
+				dev->path_data.tbvpm |= tbcpm;
 				dasd_schedule_device_bh(dev);
 			}
 		}
 	}
-	return PSF_CUIR_COMPLETED;
+	/* notify user about all paths affected by CUIR action */
+	dasd_eckd_cuir_notify_user(device, paths, sch_id, CUIR_RESUME);
+	return 0;
 }
 
 static void dasd_eckd_handle_cuir(struct dasd_device *device, void *messages,
···
 	struct channel_path_desc *desc;
 	struct subchannel_id sch_id;
 	int pos, response;
-	ccw_device_get_schid(device->cdev, &sch_id);
 
+	DBF_DEV_EVENT(DBF_WARNING, device,
+		      "CUIR request: %016llx %016llx %016llx %08x",
+		      ((u64 *)cuir)[0], ((u64 *)cuir)[1], ((u64 *)cuir)[2],
+		      ((u32 *)cuir)[3]);
+	ccw_device_get_schid(device->cdev, &sch_id);
 	/* get position of path in mask */
 	pos = 8 - ffs(lpum);
 	/* get channel path descriptor from this position */
···
 
 	if (cuir->code == CUIR_QUIESCE) {
 		/* quiesce */
-		response = dasd_eckd_cuir_quiesce(device, lpum, desc, sch_id);
+		if (dasd_eckd_cuir_quiesce(device, lpum, sch_id, cuir))
+			response = PSF_CUIR_LAST_PATH;
+		else
+			response = PSF_CUIR_COMPLETED;
 	} else if (cuir->code == CUIR_RESUME) {
 		/* resume */
-		response = dasd_eckd_cuir_resume(device, lpum, desc, sch_id);
+		dasd_eckd_cuir_resume(device, lpum, sch_id, cuir);
+		response = PSF_CUIR_COMPLETED;
 	} else
 		response = PSF_CUIR_NOT_SUPPORTED;
 
-	dasd_eckd_psf_cuir_response(device, response, cuir->message_id,
-				    desc, sch_id);
-
+	dasd_eckd_psf_cuir_response(device, response,
+				    cuir->message_id, desc, sch_id);
+	DBF_DEV_EVENT(DBF_WARNING, device,
+		      "CUIR response: %d on message ID %08x", response,
+		      cuir->message_id);
 	/* free descriptor copy */
 	kfree(desc);
+	/* to make sure there is no attention left schedule work again */
+	device->discipline->check_attention(device, lpum);
 }
 
 static void dasd_eckd_check_attention_work(struct work_struct *work)
···
 
 	data = container_of(work, struct check_attention_work_data, worker);
 	device = data->device;
-
 	messages = kzalloc(sizeof(*messages), GFP_KERNEL);
 	if (!messages) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			      "Could not allocate attention message buffer");
 		goto out;
 	}
-
 	rc = dasd_eckd_read_message_buffer(device, messages, data->lpum);
 	if (rc)
 		goto out;
-
 	if (messages->length == ATTENTION_LENGTH_CUIR &&
 	    messages->format == ATTENTION_FORMAT_CUIR)
 		dasd_eckd_handle_cuir(device, messages, data->lpum);
-
 out:
 	dasd_put_device(device);
 	kfree(messages);

drivers/s390/block/dasd_eckd.h

···
 		__u8 identifier:2;
 		__u8 reserved:6;
 	} __attribute__ ((packed)) flags;
-	__u8 reserved[5];
+	__u8 record_selector;
+	__u8 reserved[4];
 	struct {
 		__u8 value:2;
 		__u8 number:6;
···
 	struct dasd_device *next;
 };
 
+struct dasd_conf_data {
+	struct dasd_ned neds[5];
+	u8 reserved[64];
+	struct dasd_gneq gneq;
+} __packed;
+
 struct dasd_eckd_private {
 	struct dasd_eckd_characteristics rdc_data;
 	u8 *conf_data;
 	int conf_len;
+	/* per path configuration data */
+	struct dasd_conf_data *path_conf_data[8];
 	/* pointers to specific parts in the conf_data */
 	struct dasd_ned *ned;
 	struct dasd_sneq *sneq;