Merge branch 'master' into upstream

11 files changed, 270 insertions, 70 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index a3bfebc..cfb1fff 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -315,6 +315,11 @@ dasd_increase_state(struct dasd_device *device)
 		rc = dasd_state_basic_to_ready(device);
 
 	if (!rc &&
+	    device->state == DASD_STATE_UNFMT &&
+	    device->target > DASD_STATE_UNFMT)
+		rc = -EPERM;
+
+	if (!rc &&
 	    device->state == DASD_STATE_READY &&
 	    device->target >= DASD_STATE_ONLINE)
 		rc = dasd_state_ready_to_online(device);
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index c1c6f13..216bc4f 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -45,6 +45,7 @@ struct dasd_devmap {
         unsigned int devindex;
         unsigned short features;
 	struct dasd_device *device;
+	struct dasd_uid uid;
 };
 
 /*
@@ -716,6 +717,68 @@ dasd_discipline_show(struct device *dev, struct device_attribute *attr, char *bu
 
 static DEVICE_ATTR(discipline, 0444, dasd_discipline_show, NULL);
 
+static ssize_t
+dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	int alias;
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap))
+		alias = devmap->uid.alias;
+	else
+		alias = 0;
+	spin_unlock(&dasd_devmap_lock);
+
+	return sprintf(buf, alias ? "1\n" : "0\n");
+}
+
+static DEVICE_ATTR(alias, 0444, dasd_alias_show, NULL);
+
+static ssize_t
+dasd_vendor_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	char *vendor;
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
+		vendor = devmap->uid.vendor;
+	else
+		vendor = "";
+	spin_unlock(&dasd_devmap_lock);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
+}
+
+static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);
+
+#define UID_STRLEN ( /* vendor */ 3 + 1 + /* serial    */ 14 + 1 +\
+		     /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1)
+
+static ssize_t
+dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	char uid[UID_STRLEN];
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
+		snprintf(uid, sizeof(uid), "%s.%s.%04x.%02x",
+			 devmap->uid.vendor, devmap->uid.serial,
+			 devmap->uid.ssid, devmap->uid.unit_addr);
+	else
+		uid[0] = 0;
+	spin_unlock(&dasd_devmap_lock);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", uid);
+}
+
+static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);
+
 /*
  * extended error-reporting
  */
@@ -759,6 +822,9 @@ static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);
 static struct attribute * dasd_attrs[] = {
 	&dev_attr_readonly.attr,
 	&dev_attr_discipline.attr,
+	&dev_attr_alias.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_uid.attr,
 	&dev_attr_use_diag.attr,
 	&dev_attr_eer_enabled.attr,
 	NULL,
@@ -768,6 +834,42 @@ static struct attribute_group dasd_attr_group = {
 	.attrs = dasd_attrs,
 };
 
+
+/*
+ * Return copy of the device unique identifier.
+ */
+int
+dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
+{
+	struct dasd_devmap *devmap;
+
+	devmap = dasd_find_busid(cdev->dev.bus_id);
+	if (IS_ERR(devmap))
+		return PTR_ERR(devmap);
+	spin_lock(&dasd_devmap_lock);
+	*uid = devmap->uid;
+	spin_unlock(&dasd_devmap_lock);
+	return 0;
+}
+
+/*
+ * Register the given device unique identifier into devmap struct.
+ */
+int
+dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
+{
+	struct dasd_devmap *devmap;
+
+	devmap = dasd_find_busid(cdev->dev.bus_id);
+	if (IS_ERR(devmap))
+		return PTR_ERR(devmap);
+	spin_lock(&dasd_devmap_lock);
+	devmap->uid = *uid;
+	spin_unlock(&dasd_devmap_lock);
+	return 0;
+}
+EXPORT_SYMBOL(dasd_set_uid);
+
 /*
  * Return value of the specified feature.
  */
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index ee09ef3..7d5a6cee 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -446,6 +446,39 @@ dasd_eckd_cdl_reclen(int recid)
 	return LABEL_SIZE;
 }
 
+/*
+ * Generate device unique id that specifies the physical device.
+ */
+static int
+dasd_eckd_generate_uid(struct dasd_device *device, struct dasd_uid *uid)
+{
+	struct dasd_eckd_private *private;
+	struct dasd_eckd_confdata *confdata;
+
+	private = (struct dasd_eckd_private *) device->private;
+	if (!private)
+		return -ENODEV;
+	confdata = &private->conf_data;
+	if (!confdata)
+		return -ENODEV;
+
+	memset(uid, 0, sizeof(struct dasd_uid));
+	strncpy(uid->vendor, confdata->ned1.HDA_manufacturer,
+		sizeof(uid->vendor) - 1);
+	EBCASC(uid->vendor, sizeof(uid->vendor) - 1);
+	strncpy(uid->serial, confdata->ned1.HDA_location,
+		sizeof(uid->serial) - 1);
+	EBCASC(uid->serial, sizeof(uid->serial) - 1);
+	uid->ssid = confdata->neq.subsystemID;
+	if (confdata->ned2.sneq.flags == 0x40) {
+		uid->alias = 1;
+		uid->unit_addr = confdata->ned2.sneq.base_unit_addr;
+	} else
+		uid->unit_addr = confdata->ned1.unit_addr;
+
+	return 0;
+}
+
 static int
 dasd_eckd_read_conf(struct dasd_device *device)
 {
@@ -507,11 +540,15 @@ dasd_eckd_read_conf(struct dasd_device *device)
 	return 0;
 }
 
-
+/*
+ * Check device characteristics.
+ * If the device is accessible using ECKD discipline, the device is enabled.
+ */
 static int
 dasd_eckd_check_characteristics(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private;
+	struct dasd_uid uid;
 	void *rdc_data;
 	int rc;
 
@@ -536,6 +573,7 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 
 	/* Read Device Characteristics */
 	rdc_data = (void *) &(private->rdc_data);
+	memset(rdc_data, 0, sizeof(rdc_data));
 	rc = read_dev_chars(device->cdev, &rdc_data, 64);
 	if (rc) {
 		DEV_MESSAGE(KERN_WARNING, device,
@@ -556,8 +594,17 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 
 	/* Read Configuration Data */
 	rc = dasd_eckd_read_conf (device);
-	return rc;
+	if (rc)
+		return rc;
+
+	/* Generate device unique id and register in devmap */
+	rc = dasd_eckd_generate_uid(device, &uid);
+	if (rc)
+		return rc;
 
+	rc = dasd_set_uid(device->cdev, &uid);
+
+	return rc;
 }
 
 static struct dasd_ccw_req *
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index ad8524b..d5734e9 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -228,26 +228,36 @@ struct dasd_eckd_confdata {
 		unsigned char HDA_manufacturer[3];
 		unsigned char HDA_location[2];
 		unsigned char HDA_seqno[12];
-		__u16 ID;
+		__u8 ID;
+		__u8 unit_addr;
 	} __attribute__ ((packed)) ned1;
-	struct {
+	union {
 		struct {
-			unsigned char identifier:2;
-			unsigned char token_id:1;
-			unsigned char sno_valid:1;
-			unsigned char subst_sno:1;
-			unsigned char recNED:1;
-			unsigned char emuNED:1;
-			unsigned char reserved:1;
-		} __attribute__ ((packed)) flags;
-		__u8 descriptor;
-		__u8 reserved[2];
-		unsigned char dev_type[6];
-		unsigned char dev_model[3];
-		unsigned char DASD_manufacturer[3];
-		unsigned char DASD_location[2];
-		unsigned char DASD_seqno[12];
-		__u16 ID;
+			struct {
+				unsigned char identifier:2;
+				unsigned char token_id:1;
+				unsigned char sno_valid:1;
+				unsigned char subst_sno:1;
+				unsigned char recNED:1;
+				unsigned char emuNED:1;
+				unsigned char reserved:1;
+			} __attribute__ ((packed)) flags;
+			__u8 descriptor;
+			__u8 reserved[2];
+			unsigned char dev_type[6];
+			unsigned char dev_model[3];
+			unsigned char DASD_manufacturer[3];
+			unsigned char DASD_location[2];
+			unsigned char DASD_seqno[12];
+			__u16 ID;
+		} __attribute__ ((packed)) ned;
+		struct {
+			unsigned char flags;            /* byte  0    */
+			unsigned char res2[7];          /* byte  1- 7 */
+			unsigned char sua_flags;	/* byte  8    */
+			__u8 base_unit_addr;            /* byte  9    */
+			unsigned char res3[22];	        /* byte 10-31 */
+		} __attribute__ ((packed)) sneq;
 	} __attribute__ ((packed)) ned2;
 	struct {
 		struct {
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 4293ba8..d4b13e3 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -268,6 +268,16 @@ struct dasd_discipline {
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
 
+/*
+ * Unique identifier for dasd device.
+ */
+struct dasd_uid {
+	__u8 alias;
+	char vendor[4];
+	char serial[15];
+	__u16 ssid;
+	__u8 unit_addr;
+};
 
 /*
  * Notification numbers for extended error reporting notifications:
@@ -516,6 +526,8 @@ void dasd_devmap_exit(void);
 struct dasd_device *dasd_create_device(struct ccw_device *);
 void dasd_delete_device(struct dasd_device *);
 
+int dasd_get_uid(struct ccw_device *, struct dasd_uid *);
+int dasd_set_uid(struct ccw_device *, struct dasd_uid *);
 int dasd_get_feature(struct ccw_device *, int);
 int dasd_set_feature(struct ccw_device *, int, int);
 
diff --git a/drivers/s390/char/tape_3590.c b/drivers/s390/char/tape_3590.c
index c3915f6..d71ef1a 100644
--- a/drivers/s390/char/tape_3590.c
+++ b/drivers/s390/char/tape_3590.c
@@ -230,14 +230,16 @@ tape_3590_read_attmsg(struct tape_device *device)
  * These functions are used to schedule follow-up actions from within an
  * interrupt context (like unsolicited interrupts).
  */
+struct work_handler_data {
+	struct tape_device *device;
+	enum tape_op        op;
+	struct work_struct  work;
+};
+
 static void
 tape_3590_work_handler(void *data)
 {
-	struct {
-		struct tape_device *device;
-		enum tape_op op;
-		struct work_struct work;
-	} *p = data;
+	struct work_handler_data *p = data;
 
 	switch (p->op) {
 	case TO_MSEN:
@@ -257,11 +259,7 @@ tape_3590_work_handler(void *data)
 static int
 tape_3590_schedule_work(struct tape_device *device, enum tape_op op)
 {
-	struct {
-		struct tape_device *device;
-		enum tape_op op;
-		struct work_struct work;
-	} *p;
+	struct work_handler_data *p;
 
 	if ((p = kzalloc(sizeof(*p), GFP_ATOMIC)) == NULL)
 		return -ENOMEM;
@@ -316,7 +314,7 @@ tape_3590_bread(struct tape_device *device, struct request *req)
 
 	rq_for_each_bio(bio, req) {
 		bio_for_each_segment(bv, bio, i) {
-			dst = kmap(bv->bv_page) + bv->bv_offset;
+			dst = page_address(bv->bv_page) + bv->bv_offset;
 			for (off = 0; off < bv->bv_len;
 			     off += TAPEBLOCK_HSEC_SIZE) {
 				ccw->flags = CCW_FLAG_CC;
@@ -1168,6 +1166,7 @@ tape_3590_setup_device(struct tape_device *device)
 static void
 tape_3590_cleanup_device(struct tape_device *device)
 {
+	flush_scheduled_work();
 	tape_std_unassign(device);
 
 	kfree(device->discdata);
@@ -1234,6 +1233,7 @@ static struct tape_discipline tape_discipline_3590 = {
 
 static struct ccw_device_id tape_3590_ids[] = {
 	{CCW_DEVICE_DEVTYPE(0x3590, 0, 0x3590, 0), .driver_info = tape_3590},
+	{CCW_DEVICE_DEVTYPE(0x3592, 0, 0x3592, 0), .driver_info = tape_3592},
 	{ /* end of list */ }
 };
 
diff --git a/drivers/s390/char/tape_std.h b/drivers/s390/char/tape_std.h
index 2d31179..1fc9523 100644
--- a/drivers/s390/char/tape_std.h
+++ b/drivers/s390/char/tape_std.h
@@ -153,6 +153,7 @@ enum s390_tape_type {
         tape_3480,
         tape_3490,
         tape_3590,
+        tape_3592,
 };
 
 #endif // _TAPE_STD_H
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 6412b2c..72187e5 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -242,28 +242,10 @@ s390_subchannel_remove_chpid(struct device *dev, void *data)
 	if (sch->vpm == mask)
 		goto out_unreg;
 
-	if ((sch->schib.scsw.actl & (SCSW_ACTL_CLEAR_PEND |
-				     SCSW_ACTL_HALT_PEND |
-				     SCSW_ACTL_START_PEND |
-				     SCSW_ACTL_RESUME_PEND)) &&
-	    (sch->schib.pmcw.lpum == mask)) {
-		int cc = cio_cancel(sch);
-		
-		if (cc == -ENODEV)
-			goto out_unreg;
-
-		if (cc == -EINVAL) {
-			cc = cio_clear(sch);
-			if (cc == -ENODEV)
-				goto out_unreg;
-			/* Call handler. */
-			if (sch->driver && sch->driver->termination)
-				sch->driver->termination(&sch->dev);
-			goto out_unlock;
-		}
-	} else if ((sch->schib.scsw.actl & SCSW_ACTL_DEVACT) &&
-		   (sch->schib.scsw.actl & SCSW_ACTL_SCHACT) &&
-		   (sch->schib.pmcw.lpum == mask)) {
+	if ((sch->schib.scsw.actl & SCSW_ACTL_DEVACT) &&
+	    (sch->schib.scsw.actl & SCSW_ACTL_SCHACT) &&
+	    (sch->schib.pmcw.lpum == mask) &&
+	    (sch->vpm == 0)) {
 		int cc;
 
 		cc = cio_clear(sch);
@@ -653,13 +635,13 @@ __chp_add(struct subchannel_id schid, void *data)
 		if (sch->schib.pmcw.chpid[i] == chp->id) {
 			if (stsch(sch->schid, &sch->schib) != 0) {
 				/* Endgame. */
-				spin_unlock(&sch->lock);
+				spin_unlock_irq(&sch->lock);
 				return -ENXIO;
 			}
 			break;
 		}
 	if (i==8) {
-		spin_unlock(&sch->lock);
+		spin_unlock_irq(&sch->lock);
 		return 0;
 	}
 	sch->lpm = ((sch->schib.pmcw.pim &
diff --git a/drivers/s390/cio/qdio.c b/drivers/s390/cio/qdio.c
index 814f925..96f5192 100644
--- a/drivers/s390/cio/qdio.c
+++ b/drivers/s390/cio/qdio.c
@@ -38,6 +38,7 @@
 #include <linux/kernel.h>
 #include <linux/proc_fs.h>
 #include <linux/timer.h>
+#include <linux/mempool.h>
 
 #include <asm/ccwdev.h>
 #include <asm/io.h>
@@ -80,6 +81,8 @@ static int indicator_used[INDICATORS_PER_CACHELINE];
 static __u32 * volatile indicators;
 static __u32 volatile spare_indicator;
 static atomic_t spare_indicator_usecount;
+#define QDIO_MEMPOOL_SCSSC_ELEMENTS 2
+static mempool_t *qdio_mempool_scssc;
 
 static debug_info_t *qdio_dbf_setup;
 static debug_info_t *qdio_dbf_sbal;
@@ -1637,7 +1640,7 @@ next:
 
 	}
 	kfree(irq_ptr->qdr);
-	kfree(irq_ptr);
+	free_page((unsigned long) irq_ptr);
 }
 
 static void
@@ -2304,7 +2307,7 @@ qdio_get_ssqd_information(struct qdio_irq *irq_ptr)
 
 	QDIO_DBF_TEXT0(0,setup,"getssqd");
 	qdioac = 0;
-	ssqd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	ssqd_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);
 	if (!ssqd_area) {
 	        QDIO_PRINT_WARN("Could not get memory for chsc. Using all " \
 				"SIGAs for sch x%x.\n", irq_ptr->schid.sch_no);
@@ -2364,7 +2367,7 @@ qdio_get_ssqd_information(struct qdio_irq *irq_ptr)
 out:
 	qdio_check_subchannel_qebsm(irq_ptr, qdioac,
 				    ssqd_area->sch_token);
-	free_page ((unsigned long) ssqd_area);
+	mempool_free(ssqd_area, qdio_mempool_scssc);
 	irq_ptr->qdioac = qdioac;
 }
 
@@ -2458,7 +2461,7 @@ tiqdio_set_subchannel_ind(struct qdio_irq *irq_ptr, int reset_to_zero)
 			virt_to_phys((volatile void *)irq_ptr->dev_st_chg_ind);
 	}
 
-	scssc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	scssc_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);
 	if (!scssc_area) {
 		QDIO_PRINT_WARN("No memory for setting indicators on " \
 				"subchannel 0.%x.%x.\n",
@@ -2514,7 +2517,7 @@ tiqdio_set_subchannel_ind(struct qdio_irq *irq_ptr, int reset_to_zero)
 	QDIO_DBF_HEX2(0,setup,&real_addr_dev_st_chg_ind,sizeof(unsigned long));
 	result = 0;
 out:
-	free_page ((unsigned long) scssc_area);
+	mempool_free(scssc_area, qdio_mempool_scssc);
 	return result;
 
 }
@@ -2543,7 +2546,7 @@ tiqdio_set_delay_target(struct qdio_irq *irq_ptr, unsigned long delay_target)
 	if (!irq_ptr->is_thinint_irq)
 		return -ENODEV;
 
-	scsscf_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	scsscf_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);
 	if (!scsscf_area) {
 		QDIO_PRINT_WARN("No memory for setting delay target on " \
 				"subchannel 0.%x.%x.\n",
@@ -2581,7 +2584,7 @@ tiqdio_set_delay_target(struct qdio_irq *irq_ptr, unsigned long delay_target)
 	QDIO_DBF_HEX2(0,trace,&delay_target,sizeof(unsigned long));
 	result = 0; /* not critical */
 out:
-	free_page ((unsigned long) scsscf_area);
+	mempool_free(scsscf_area, qdio_mempool_scssc);
 	return result;
 }
 
@@ -2980,7 +2983,7 @@ qdio_allocate(struct qdio_initialize *init_data)
 	qdio_allocate_do_dbf(init_data);
 
 	/* create irq */
-	irq_ptr = kzalloc(sizeof(struct qdio_irq), GFP_KERNEL | GFP_DMA);
+	irq_ptr = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 
 	QDIO_DBF_TEXT0(0,setup,"irq_ptr:");
 	QDIO_DBF_HEX0(0,setup,&irq_ptr,sizeof(void*));
@@ -2995,7 +2998,7 @@ qdio_allocate(struct qdio_initialize *init_data)
 	/* QDR must be in DMA area since CCW data address is only 32 bit */
 	irq_ptr->qdr=kmalloc(sizeof(struct qdr), GFP_KERNEL | GFP_DMA);
   	if (!(irq_ptr->qdr)) {
-   		kfree(irq_ptr);
+   		free_page((unsigned long) irq_ptr);
     		QDIO_PRINT_ERR("kmalloc of irq_ptr->qdr failed!\n");
 		return -ENOMEM;
        	}
@@ -3780,6 +3783,16 @@ oom:
 	return -ENOMEM;
 }
 
+static void *qdio_mempool_alloc(gfp_t gfp_mask, void *size)
+{
+	return (void *) get_zeroed_page(gfp_mask|GFP_DMA);
+}
+
+static void qdio_mempool_free(void *element, void *size)
+{
+	free_page((unsigned long) element);
+}
+
 static int __init
 init_QDIO(void)
 {
@@ -3809,6 +3822,10 @@ init_QDIO(void)
 
 	qdio_add_procfs_entry();
 
+	qdio_mempool_scssc = mempool_create(QDIO_MEMPOOL_SCSSC_ELEMENTS,
+					    qdio_mempool_alloc,
+					    qdio_mempool_free, NULL);
+
 	if (tiqdio_check_chsc_availability())
 		QDIO_PRINT_ERR("Not all CHSCs supported. Continuing.\n");
 
@@ -3824,6 +3841,7 @@ cleanup_QDIO(void)
 	qdio_remove_procfs_entry();
 	qdio_release_qdio_memory();
 	qdio_unregister_dbf_views();
+	mempool_destroy(qdio_mempool_scssc);
 
   	printk("qdio: %s: module removed\n",version);
 }
diff --git a/drivers/s390/net/qeth_main.c b/drivers/s390/net/qeth_main.c
index b3c6e79..cb14642 100644
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -8014,7 +8014,6 @@ static int (*qeth_old_arp_constructor) (struct neighbour *);
 
 static struct neigh_ops arp_direct_ops_template = {
 	.family = AF_INET,
-	.destructor = NULL,
 	.solicit = NULL,
 	.error_report = NULL,
 	.output = dev_queue_xmit,
diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index 3bf4666..f99e553 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 #include <linux/errno.h>
 #include <linux/workqueue.h>
+#include <linux/time.h>
 
 #include <asm/lowcore.h>
 
@@ -362,12 +363,19 @@ s390_revalidate_registers(struct mci *mci)
 	return kill_task;
 }
 
+#define MAX_IPD_COUNT	29
+#define MAX_IPD_TIME	(5 * 60 * USEC_PER_SEC) /* 5 minutes */
+
 /*
  * machine check handler.
  */
 void
 s390_do_machine_check(struct pt_regs *regs)
 {
+	static DEFINE_SPINLOCK(ipd_lock);
+	static unsigned long long last_ipd;
+	static int ipd_count;
+	unsigned long long tmp;
 	struct mci *mci;
 	struct mcck_struct *mcck;
 	int umode;
@@ -404,11 +412,27 @@ s390_do_machine_check(struct pt_regs *regs)
 				s390_handle_damage("processing backup machine "
 						   "check with damage.");
 			}
-			if (!umode)
-				s390_handle_damage("processing backup machine "
-						   "check in kernel mode.");
-			mcck->kill_task = 1;
-			mcck->mcck_code = *(unsigned long long *) mci;
+
+			/*
+			 * Nullifying exigent condition, therefore we might
+			 * retry this instruction.
+			 */
+
+			spin_lock(&ipd_lock);
+
+			tmp = get_clock();
+
+			if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
+				ipd_count++;
+			else
+				ipd_count = 1;
+
+			last_ipd = tmp;
+
+			if (ipd_count == MAX_IPD_COUNT)
+				s390_handle_damage("too many ipd retries.");
+
+			spin_unlock(&ipd_lock);
 		}
 		else {
 			/* Processing damage -> stopping machine */