s390/dasd: channel path aware error recovery

With this feature, the DASD device driver more robustly handles DASDs
that are attached via multiple channel paths and are subject to
constant Interface-Control-Checks (IFCCs) and Channel-Control-Checks
(CCCs) or loss of High-Performance-FICON (HPF) functionality on one or
more of these paths.

If a channel path does not work correctly, it is removed from normal
operation as long as other channel paths are available. All extended
error recovery states can be queried and reset via user space
interfaces.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 146 insertions, 64 deletions

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 51fdf31aa8eb..67bf50c9946f 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1044,6 +1044,9 @@ static void dasd_eckd_clear_conf_data(struct dasd_device *device)
 	for (i = 0; i < 8; i++) {
 		kfree(device->path[i].conf_data);
 		device->path[i].conf_data = NULL;
+		device->path[i].cssid = 0;
+		device->path[i].ssid = 0;
+		device->path[i].chpid = 0;
 	}
 }
 
@@ -1057,9 +1060,12 @@ static int dasd_eckd_read_conf(struct dasd_device *device)
 	struct dasd_eckd_private *private, path_private;
 	struct dasd_uid *uid;
 	char print_path_uid[60], print_device_uid[60];
+	struct channel_path_desc *chp_desc;
+	struct subchannel_id sch_id;
 
 	private = device->private;
 	opm = ccw_device_get_path_mask(device->cdev);
+	ccw_device_get_schid(device->cdev, &sch_id);
 	conf_data_saved = 0;
 	path_err = 0;
 	/* get configuration data per operational path */
@@ -1097,6 +1103,12 @@ static int dasd_eckd_read_conf(struct dasd_device *device)
 			pos = pathmask_to_pos(lpm);
 			/* store per path conf_data */
 			device->path[pos].conf_data = conf_data;
+			device->path[pos].cssid = sch_id.cssid;
+			device->path[pos].ssid = sch_id.ssid;
+			chp_desc = ccw_device_get_chp_desc(device->cdev, pos);
+			if (chp_desc)
+				device->path[pos].chpid = chp_desc->chpid;
+			kfree(chp_desc);
 			/*
 			 * build device UID that other path data
 			 * can be compared to it
@@ -1157,6 +1169,12 @@ static int dasd_eckd_read_conf(struct dasd_device *device)
 			pos = pathmask_to_pos(lpm);
 			/* store per path conf_data */
 			device->path[pos].conf_data = conf_data;
+			device->path[pos].cssid = sch_id.cssid;
+			device->path[pos].ssid = sch_id.ssid;
+			chp_desc = ccw_device_get_chp_desc(device->cdev, pos);
+			if (chp_desc)
+				device->path[pos].chpid = chp_desc->chpid;
+			kfree(chp_desc);
 			path_private.conf_data = NULL;
 			path_private.conf_len = 0;
 		}
@@ -1179,6 +1197,32 @@ static int dasd_eckd_read_conf(struct dasd_device *device)
 	return path_err;
 }
 
+static u32 get_fcx_max_data(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private = device->private;
+	int fcx_in_css, fcx_in_gneq, fcx_in_features;
+	int tpm, mdc;
+
+	if (dasd_nofcx)
+		return 0;
+	/* is transport mode supported? */
+	fcx_in_css = css_general_characteristics.fcx;
+	fcx_in_gneq = private->gneq->reserved2[7] & 0x04;
+	fcx_in_features = private->features.feature[40] & 0x80;
+	tpm = fcx_in_css && fcx_in_gneq && fcx_in_features;
+
+	if (!tpm)
+		return 0;
+
+	mdc = ccw_device_get_mdc(device->cdev, 0);
+	if (mdc < 0) {
+		dev_warn(&device->cdev->dev, "Detecting the maximum supported data size for zHPF requests failed\n");
+		return 0;
+	} else {
+		return (u32)mdc * FCX_MAX_DATA_FACTOR;
+	}
+}
+
 static int verify_fcx_max_data(struct dasd_device *device, __u8 lpm)
 {
 	struct dasd_eckd_private *private = device->private;
@@ -1438,6 +1482,19 @@ static int dasd_eckd_verify_path(struct dasd_device *device, __u8 lpm)
 	return 0;
 }
 
+static void dasd_eckd_reset_path(struct dasd_device *device, __u8 pm)
+{
+	struct dasd_eckd_private *private = device->private;
+	unsigned long flags;
+
+	if (!private->fcx_max_data)
+		private->fcx_max_data = get_fcx_max_data(device);
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	dasd_path_set_tbvpm(device, pm ? : dasd_path_get_notoperpm(device));
+	dasd_schedule_device_bh(device);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+}
+
 static int dasd_eckd_read_features(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private = device->private;
@@ -1634,32 +1691,6 @@ static void dasd_eckd_kick_validate_server(struct dasd_device *device)
 		dasd_put_device(device);
 }
 
-static u32 get_fcx_max_data(struct dasd_device *device)
-{
-	struct dasd_eckd_private *private = device->private;
-	int fcx_in_css, fcx_in_gneq, fcx_in_features;
-	int tpm, mdc;
-
-	if (dasd_nofcx)
-		return 0;
-	/* is transport mode supported? */
-	fcx_in_css = css_general_characteristics.fcx;
-	fcx_in_gneq = private->gneq->reserved2[7] & 0x04;
-	fcx_in_features = private->features.feature[40] & 0x80;
-	tpm = fcx_in_css && fcx_in_gneq && fcx_in_features;
-
-	if (!tpm)
-		return 0;
-
-	mdc = ccw_device_get_mdc(device->cdev, 0);
-	if (mdc < 0) {
-		dev_warn(&device->cdev->dev, "Detecting the maximum supported"
-			 " data size for zHPF requests failed\n");
-		return 0;
-	} else
-		return (u32)mdc * FCX_MAX_DATA_FACTOR;
-}
-
 /*
  * Check device characteristics.
  * If the device is accessible using ECKD discipline, the device is enabled.
@@ -1711,10 +1742,11 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 	if (rc)
 		goto out_err1;
 
-	/* set default timeout */
+	/* set some default values */
 	device->default_expires = DASD_EXPIRES;
-	/* set default retry count */
 	device->default_retries = DASD_RETRIES;
+	device->path_thrhld = DASD_ECKD_PATH_THRHLD;
+	device->path_interval = DASD_ECKD_PATH_INTERVAL;
 
 	if (private->gneq) {
 		value = 1;
@@ -1828,6 +1860,9 @@ static void dasd_eckd_uncheck_device(struct dasd_device *device)
 			private->conf_len = 0;
 		}
 		device->path[i].conf_data = NULL;
+		device->path[i].cssid = 0;
+		device->path[i].ssid = 0;
+		device->path[i].chpid = 0;
 	}
 	kfree(private->conf_data);
 	private->conf_data = NULL;
@@ -4765,7 +4800,8 @@ static void dasd_eckd_dump_sense_tcw(struct dasd_device *device,
 		       req, scsw_cc(&irb->scsw), scsw_fctl(&irb->scsw),
 		       scsw_actl(&irb->scsw), scsw_stctl(&irb->scsw),
 		       scsw_dstat(&irb->scsw), scsw_cstat(&irb->scsw),
-		       irb->scsw.tm.fcxs, irb->scsw.tm.schxs,
+		       irb->scsw.tm.fcxs,
+		       (irb->scsw.tm.ifob << 7) | irb->scsw.tm.sesq,
 		       req ? req->intrc : 0);
 	len += sprintf(page + len, PRINTK_HEADER
 		       " device %s: Failing TCW: %p\n",
@@ -5288,11 +5324,10 @@ static int dasd_hosts_print(struct dasd_device *device, struct seq_file *m)
  */
 static int
 dasd_eckd_psf_cuir_response(struct dasd_device *device, int response,
-			    __u32 message_id,
-			    struct channel_path_desc *desc,
-			    struct subchannel_id sch_id)
+			    __u32 message_id, __u8 lpum)
 {
 	struct dasd_psf_cuir_response *psf_cuir;
+	int pos = pathmask_to_pos(lpum);
 	struct dasd_ccw_req *cqr;
 	struct ccw1 *ccw;
 	int rc;
@@ -5310,11 +5345,10 @@ dasd_eckd_psf_cuir_response(struct dasd_device *device, int response,
 	psf_cuir = (struct dasd_psf_cuir_response *)cqr->data;
 	psf_cuir->order = PSF_ORDER_CUIR_RESPONSE;
 	psf_cuir->cc = response;
-	if (desc)
-		psf_cuir->chpid = desc->chpid;
+	psf_cuir->chpid = device->path[pos].chpid;
 	psf_cuir->message_id = message_id;
-	psf_cuir->cssid = sch_id.cssid;
-	psf_cuir->ssid = sch_id.ssid;
+	psf_cuir->cssid = device->path[pos].cssid;
+	psf_cuir->ssid = device->path[pos].ssid;
 	ccw = cqr->cpaddr;
 	ccw->cmd_code = DASD_ECKD_CCW_PSF;
 	ccw->cda = (__u32)(addr_t)psf_cuir;
@@ -5427,27 +5461,23 @@ static int dasd_eckd_cuir_scope(struct dasd_device *device, __u8 lpum,
 }
 
 static void dasd_eckd_cuir_notify_user(struct dasd_device *device,
-				       unsigned long paths,
-				       struct subchannel_id sch_id, int action)
+				       unsigned long paths, int action)
 {
-	struct channel_path_desc *desc;
 	int pos;
 
 	while (paths) {
 		/* get position of bit in mask */
-		pos = ffs(paths) - 1;
+		pos = 8 - ffs(paths);
 		/* 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);
+			pr_warn("Service on the storage server caused path %x.%02x to go offline",
+				device->path[pos].cssid,
+				device->path[pos].chpid);
 		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);
+			pr_info("Path %x.%02x is back online after service on the storage server",
+				device->path[pos].cssid,
+				device->path[pos].chpid);
+		clear_bit(7 - pos, &paths);
 	}
 }
 
@@ -5480,7 +5510,6 @@ static int dasd_eckd_cuir_remove_path(struct dasd_device *device, __u8 lpum,
  * notify the already set offline devices again
  */
 static int dasd_eckd_cuir_quiesce(struct dasd_device *device, __u8 lpum,
-				  struct subchannel_id sch_id,
 				  struct dasd_cuir_message *cuir)
 {
 	struct dasd_eckd_private *private = device->private;
@@ -5535,14 +5564,13 @@ static int dasd_eckd_cuir_quiesce(struct dasd_device *device, __u8 lpum,
 		}
 	}
 	/* notify user about all paths affected by CUIR action */
-	dasd_eckd_cuir_notify_user(device, paths, sch_id, CUIR_QUIESCE);
+	dasd_eckd_cuir_notify_user(device, paths, CUIR_QUIESCE);
 	return 0;
 out_err:
 	return tbcpm;
 }
 
 static int dasd_eckd_cuir_resume(struct dasd_device *device, __u8 lpum,
-				 struct subchannel_id sch_id,
 				 struct dasd_cuir_message *cuir)
 {
 	struct dasd_eckd_private *private = device->private;
@@ -5601,7 +5629,7 @@ static int dasd_eckd_cuir_resume(struct dasd_device *device, __u8 lpum,
 		}
 	}
 	/* notify user about all paths affected by CUIR action */
-	dasd_eckd_cuir_notify_user(device, paths, sch_id, CUIR_RESUME);
+	dasd_eckd_cuir_notify_user(device, paths, CUIR_RESUME);
 	return 0;
 }
 
@@ -5609,38 +5637,31 @@ static void dasd_eckd_handle_cuir(struct dasd_device *device, void *messages,
 				 __u8 lpum)
 {
 	struct dasd_cuir_message *cuir = messages;
-	struct channel_path_desc *desc;
-	struct subchannel_id sch_id;
-	int pos, response;
+	int response;
 
 	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);
-	pos = pathmask_to_pos(lpum);
-	desc = ccw_device_get_chp_desc(device->cdev, pos);
 
 	if (cuir->code == CUIR_QUIESCE) {
 		/* quiesce */
-		if (dasd_eckd_cuir_quiesce(device, lpum, sch_id, cuir))
+		if (dasd_eckd_cuir_quiesce(device, lpum, cuir))
 			response = PSF_CUIR_LAST_PATH;
 		else
 			response = PSF_CUIR_COMPLETED;
 	} else if (cuir->code == CUIR_RESUME) {
 		/* resume */
-		dasd_eckd_cuir_resume(device, lpum, sch_id, cuir);
+		dasd_eckd_cuir_resume(device, lpum, cuir);
 		response = PSF_CUIR_COMPLETED;
 	} else
 		response = PSF_CUIR_NOT_SUPPORTED;
 
 	dasd_eckd_psf_cuir_response(device, response,
-				    cuir->message_id, desc, sch_id);
+				    cuir->message_id, lpum);
 	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);
 }
@@ -5687,6 +5708,63 @@ static int dasd_eckd_check_attention(struct dasd_device *device, __u8 lpum)
 	return 0;
 }
 
+static int dasd_eckd_disable_hpf_path(struct dasd_device *device, __u8 lpum)
+{
+	if (~lpum & dasd_path_get_opm(device)) {
+		dasd_path_add_nohpfpm(device, lpum);
+		dasd_path_remove_opm(device, lpum);
+		dev_err(&device->cdev->dev,
+			"Channel path %02X lost HPF functionality and is disabled\n",
+			lpum);
+		return 1;
+	}
+	return 0;
+}
+
+static void dasd_eckd_disable_hpf_device(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private = device->private;
+
+	dev_err(&device->cdev->dev,
+		"High Performance FICON disabled\n");
+	private->fcx_max_data = 0;
+}
+
+static int dasd_eckd_hpf_enabled(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private = device->private;
+
+	return private->fcx_max_data ? 1 : 0;
+}
+
+static void dasd_eckd_handle_hpf_error(struct dasd_device *device,
+				       struct irb *irb)
+{
+	struct dasd_eckd_private *private = device->private;
+
+	if (!private->fcx_max_data) {
+		/* sanity check for no HPF, the error makes no sense */
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "Trying to disable HPF for a non HPF device");
+		return;
+	}
+	if (irb->scsw.tm.sesq == SCSW_SESQ_DEV_NOFCX) {
+		dasd_eckd_disable_hpf_device(device);
+	} else if (irb->scsw.tm.sesq == SCSW_SESQ_PATH_NOFCX) {
+		if (dasd_eckd_disable_hpf_path(device, irb->esw.esw1.lpum))
+			return;
+		dasd_eckd_disable_hpf_device(device);
+		dasd_path_set_tbvpm(device,
+				  dasd_path_get_hpfpm(device));
+	}
+	/*
+	 * prevent that any new I/O ist started on the device and schedule a
+	 * requeue of existing requests
+	 */
+	dasd_device_set_stop_bits(device, DASD_STOPPED_NOT_ACC);
+	dasd_schedule_requeue(device);
+}
+
 static struct ccw_driver dasd_eckd_driver = {
 	.driver = {
 		.name	= "dasd-eckd",
@@ -5755,6 +5833,10 @@ static struct dasd_discipline dasd_eckd_discipline = {
 	.check_attention = dasd_eckd_check_attention,
 	.host_access_count = dasd_eckd_host_access_count,
 	.hosts_print = dasd_hosts_print,
+	.handle_hpf_error = dasd_eckd_handle_hpf_error,
+	.disable_hpf = dasd_eckd_disable_hpf_device,
+	.hpf_enabled = dasd_eckd_hpf_enabled,
+	.reset_path = dasd_eckd_reset_path,
 };
 
 static int __init