Merge branch 'linus' into timers/urgent

Get upstream changes so dependent patches can be applied.

8 files changed, 138 insertions, 220 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 34b9ad6b3143..e2f7b6e93efd 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -373,6 +373,12 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 		rc = -EINVAL;
 		goto error;
 	}
+	/* Check if the devices are bound to the required ccw driver. */
+	if (gdev->count && gdrv && gdrv->ccw_driver &&
+	    gdev->cdev[0]->drv != gdrv->ccw_driver) {
+		rc = -EINVAL;
+		goto error;
+	}
 
 	dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 	gdev->dev.groups = ccwgroup_attr_groups;
diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index 735052ecd3e5..8e7e19b9e92c 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -43,11 +43,7 @@ static DEFINE_MUTEX(on_close_mutex);
 
 static void CHSC_LOG_HEX(int level, void *data, int length)
 {
-	while (length > 0) {
-		debug_event(chsc_debug_log_id, level, data, length);
-		length -= chsc_debug_log_id->buf_size;
-		data += chsc_debug_log_id->buf_size;
-	}
+	debug_event(chsc_debug_log_id, level, data, length);
 }
 
 MODULE_AUTHOR("IBM Corporation");
diff --git a/drivers/s390/cio/cio_debug.h b/drivers/s390/cio/cio_debug.h
index fa817efcec8f..7bdbe73707c2 100644
--- a/drivers/s390/cio/cio_debug.h
+++ b/drivers/s390/cio/cio_debug.h
@@ -23,13 +23,7 @@ extern debug_info_t *cio_debug_crw_id;
 
 static inline void CIO_HEX_EVENT(int level, void *data, int length)
 {
-	if (unlikely(!cio_debug_trace_id))
-		return;
-	while (length > 0) {
-		debug_event(cio_debug_trace_id, level, data, length);
-		length -= cio_debug_trace_id->buf_size;
-		data += cio_debug_trace_id->buf_size;
-	}
+	debug_event(cio_debug_trace_id, level, data, length);
 }
 
 #endif
diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c
index 220491d27ef4..7d59230e88bb 100644
--- a/drivers/s390/cio/cmf.c
+++ b/drivers/s390/cio/cmf.c
@@ -58,8 +58,9 @@
 
 /* indices for READCMB */
 enum cmb_index {
+	avg_utilization = -1,
  /* basic and exended format: */
-	cmb_ssch_rsch_count,
+	cmb_ssch_rsch_count = 0,
 	cmb_sample_count,
 	cmb_device_connect_time,
 	cmb_function_pending_time,
@@ -215,71 +216,52 @@ struct set_schib_struct {
 	unsigned long address;
 	wait_queue_head_t wait;
 	int ret;
-	struct kref kref;
 };
 
-static void cmf_set_schib_release(struct kref *kref)
-{
-	struct set_schib_struct *set_data;
-
-	set_data = container_of(kref, struct set_schib_struct, kref);
-	kfree(set_data);
-}
-
 #define CMF_PENDING 1
+#define SET_SCHIB_TIMEOUT (10 * HZ)
 
 static int set_schib_wait(struct ccw_device *cdev, u32 mme,
-				int mbfc, unsigned long address)
+			  int mbfc, unsigned long address)
 {
-	struct set_schib_struct *set_data;
-	int ret;
+	struct set_schib_struct set_data;
+	int ret = -ENODEV;
 
 	spin_lock_irq(cdev->ccwlock);
-	if (!cdev->private->cmb) {
-		ret = -ENODEV;
+	if (!cdev->private->cmb)
 		goto out;
-	}
-	set_data = kzalloc(sizeof(struct set_schib_struct), GFP_ATOMIC);
-	if (!set_data) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	init_waitqueue_head(&set_data->wait);
-	kref_init(&set_data->kref);
-	set_data->mme = mme;
-	set_data->mbfc = mbfc;
-	set_data->address = address;
 
 	ret = set_schib(cdev, mme, mbfc, address);
 	if (ret != -EBUSY)
-		goto out_put;
+		goto out;
 
-	if (cdev->private->state != DEV_STATE_ONLINE) {
-		/* if the device is not online, don't even try again */
-		ret = -EBUSY;
-		goto out_put;
-	}
+	/* if the device is not online, don't even try again */
+	if (cdev->private->state != DEV_STATE_ONLINE)
+		goto out;
 
-	cdev->private->state = DEV_STATE_CMFCHANGE;
-	set_data->ret = CMF_PENDING;
-	cdev->private->cmb_wait = set_data;
+	init_waitqueue_head(&set_data.wait);
+	set_data.mme = mme;
+	set_data.mbfc = mbfc;
+	set_data.address = address;
+	set_data.ret = CMF_PENDING;
 
+	cdev->private->state = DEV_STATE_CMFCHANGE;
+	cdev->private->cmb_wait = &set_data;
 	spin_unlock_irq(cdev->ccwlock);
-	if (wait_event_interruptible(set_data->wait,
-				     set_data->ret != CMF_PENDING)) {
-		spin_lock_irq(cdev->ccwlock);
-		if (set_data->ret == CMF_PENDING) {
-			set_data->ret = -ERESTARTSYS;
+
+	ret = wait_event_interruptible_timeout(set_data.wait,
+					       set_data.ret != CMF_PENDING,
+					       SET_SCHIB_TIMEOUT);
+	spin_lock_irq(cdev->ccwlock);
+	if (ret <= 0) {
+		if (set_data.ret == CMF_PENDING) {
+			set_data.ret = (ret == 0) ? -ETIME : ret;
 			if (cdev->private->state == DEV_STATE_CMFCHANGE)
 				cdev->private->state = DEV_STATE_ONLINE;
 		}
-		spin_unlock_irq(cdev->ccwlock);
 	}
-	spin_lock_irq(cdev->ccwlock);
 	cdev->private->cmb_wait = NULL;
-	ret = set_data->ret;
-out_put:
-	kref_put(&set_data->kref, cmf_set_schib_release);
+	ret = set_data.ret;
 out:
 	spin_unlock_irq(cdev->ccwlock);
 	return ret;
@@ -287,28 +269,21 @@ out:
 
 void retry_set_schib(struct ccw_device *cdev)
 {
-	struct set_schib_struct *set_data;
+	struct set_schib_struct *set_data = cdev->private->cmb_wait;
 
-	set_data = cdev->private->cmb_wait;
-	if (!set_data) {
-		WARN_ON(1);
+	if (!set_data)
 		return;
-	}
-	kref_get(&set_data->kref);
+
 	set_data->ret = set_schib(cdev, set_data->mme, set_data->mbfc,
 				  set_data->address);
 	wake_up(&set_data->wait);
-	kref_put(&set_data->kref, cmf_set_schib_release);
 }
 
 static int cmf_copy_block(struct ccw_device *cdev)
 {
-	struct subchannel *sch;
-	void *reference_buf;
-	void *hw_block;
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
 	struct cmb_data *cmb_data;
-
-	sch = to_subchannel(cdev->dev.parent);
+	void *hw_block;
 
 	if (cio_update_schib(sch))
 		return -ENODEV;
@@ -323,102 +298,65 @@ static int cmf_copy_block(struct ccw_device *cdev)
 	}
 	cmb_data = cdev->private->cmb;
 	hw_block = cmb_data->hw_block;
-	if (!memcmp(cmb_data->last_block, hw_block, cmb_data->size))
-		/* No need to copy. */
-		return 0;
-	reference_buf = kzalloc(cmb_data->size, GFP_ATOMIC);
-	if (!reference_buf)
-		return -ENOMEM;
-	/* Ensure consistency of block copied from hardware. */
-	do {
-		memcpy(cmb_data->last_block, hw_block, cmb_data->size);
-		memcpy(reference_buf, hw_block, cmb_data->size);
-	} while (memcmp(cmb_data->last_block, reference_buf, cmb_data->size));
+	memcpy(cmb_data->last_block, hw_block, cmb_data->size);
 	cmb_data->last_update = get_tod_clock();
-	kfree(reference_buf);
 	return 0;
 }
 
 struct copy_block_struct {
 	wait_queue_head_t wait;
 	int ret;
-	struct kref kref;
 };
 
-static void cmf_copy_block_release(struct kref *kref)
-{
-	struct copy_block_struct *copy_block;
-
-	copy_block = container_of(kref, struct copy_block_struct, kref);
-	kfree(copy_block);
-}
-
 static int cmf_cmb_copy_wait(struct ccw_device *cdev)
 {
-	struct copy_block_struct *copy_block;
-	int ret;
-	unsigned long flags;
+	struct copy_block_struct copy_block;
+	int ret = -ENODEV;
 
-	spin_lock_irqsave(cdev->ccwlock, flags);
-	if (!cdev->private->cmb) {
-		ret = -ENODEV;
-		goto out;
-	}
-	copy_block = kzalloc(sizeof(struct copy_block_struct), GFP_ATOMIC);
-	if (!copy_block) {
-		ret = -ENOMEM;
+	spin_lock_irq(cdev->ccwlock);
+	if (!cdev->private->cmb)
 		goto out;
-	}
-	init_waitqueue_head(&copy_block->wait);
-	kref_init(&copy_block->kref);
 
 	ret = cmf_copy_block(cdev);
 	if (ret != -EBUSY)
-		goto out_put;
+		goto out;
 
-	if (cdev->private->state != DEV_STATE_ONLINE) {
-		ret = -EBUSY;
-		goto out_put;
-	}
+	if (cdev->private->state != DEV_STATE_ONLINE)
+		goto out;
+
+	init_waitqueue_head(&copy_block.wait);
+	copy_block.ret = CMF_PENDING;
 
 	cdev->private->state = DEV_STATE_CMFUPDATE;
-	copy_block->ret = CMF_PENDING;
-	cdev->private->cmb_wait = copy_block;
+	cdev->private->cmb_wait = &copy_block;
+	spin_unlock_irq(cdev->ccwlock);
 
-	spin_unlock_irqrestore(cdev->ccwlock, flags);
-	if (wait_event_interruptible(copy_block->wait,
-				     copy_block->ret != CMF_PENDING)) {
-		spin_lock_irqsave(cdev->ccwlock, flags);
-		if (copy_block->ret == CMF_PENDING) {
-			copy_block->ret = -ERESTARTSYS;
+	ret = wait_event_interruptible(copy_block.wait,
+				       copy_block.ret != CMF_PENDING);
+	spin_lock_irq(cdev->ccwlock);
+	if (ret) {
+		if (copy_block.ret == CMF_PENDING) {
+			copy_block.ret = -ERESTARTSYS;
 			if (cdev->private->state == DEV_STATE_CMFUPDATE)
 				cdev->private->state = DEV_STATE_ONLINE;
 		}
-		spin_unlock_irqrestore(cdev->ccwlock, flags);
 	}
-	spin_lock_irqsave(cdev->ccwlock, flags);
 	cdev->private->cmb_wait = NULL;
-	ret = copy_block->ret;
-out_put:
-	kref_put(&copy_block->kref, cmf_copy_block_release);
+	ret = copy_block.ret;
 out:
-	spin_unlock_irqrestore(cdev->ccwlock, flags);
+	spin_unlock_irq(cdev->ccwlock);
 	return ret;
 }
 
 void cmf_retry_copy_block(struct ccw_device *cdev)
 {
-	struct copy_block_struct *copy_block;
+	struct copy_block_struct *copy_block = cdev->private->cmb_wait;
 
-	copy_block = cdev->private->cmb_wait;
-	if (!copy_block) {
-		WARN_ON(1);
+	if (!copy_block)
 		return;
-	}
-	kref_get(&copy_block->kref);
+
 	copy_block->ret = cmf_copy_block(cdev);
 	wake_up(&copy_block->wait);
-	kref_put(&copy_block->kref, cmf_copy_block_release);
 }
 
 static void cmf_generic_reset(struct ccw_device *cdev)
@@ -650,25 +588,44 @@ static int set_cmb(struct ccw_device *cdev, u32 mme)
 	return set_schib_wait(cdev, mme, 0, offset);
 }
 
+/* calculate utilization in 0.1 percent units */
+static u64 __cmb_utilization(u64 device_connect_time, u64 function_pending_time,
+			     u64 device_disconnect_time, u64 start_time)
+{
+	u64 utilization, elapsed_time;
+
+	utilization = time_to_nsec(device_connect_time +
+				   function_pending_time +
+				   device_disconnect_time);
+
+	elapsed_time = get_tod_clock() - start_time;
+	elapsed_time = tod_to_ns(elapsed_time);
+	elapsed_time /= 1000;
+
+	return elapsed_time ? (utilization / elapsed_time) : 0;
+}
+
 static u64 read_cmb(struct ccw_device *cdev, int index)
 {
+	struct cmb_data *cmb_data;
+	unsigned long flags;
 	struct cmb *cmb;
+	u64 ret = 0;
 	u32 val;
-	int ret;
-	unsigned long flags;
-
-	ret = cmf_cmb_copy_wait(cdev);
-	if (ret < 0)
-		return 0;
 
 	spin_lock_irqsave(cdev->ccwlock, flags);
-	if (!cdev->private->cmb) {
-		ret = 0;
+	cmb_data = cdev->private->cmb;
+	if (!cmb_data)
 		goto out;
-	}
-	cmb = ((struct cmb_data *)cdev->private->cmb)->last_block;
 
+	cmb = cmb_data->hw_block;
 	switch (index) {
+	case avg_utilization:
+		ret = __cmb_utilization(cmb->device_connect_time,
+					cmb->function_pending_time,
+					cmb->device_disconnect_time,
+					cdev->private->cmb_start_time);
+		goto out;
 	case cmb_ssch_rsch_count:
 		ret = cmb->ssch_rsch_count;
 		goto out;
@@ -691,7 +648,6 @@ static u64 read_cmb(struct ccw_device *cdev, int index)
 		val = cmb->device_active_only_time;
 		break;
 	default:
-		ret = 0;
 		goto out;
 	}
 	ret = time_to_avg_nsec(val, cmb->sample_count);
@@ -729,8 +685,7 @@ static int readall_cmb(struct ccw_device *cdev, struct cmbdata *data)
 	/* we only know values before device_busy_time */
 	data->size = offsetof(struct cmbdata, device_busy_time);
 
-	/* convert to nanoseconds */
-	data->elapsed_time = (time * 1000) >> 12;
+	data->elapsed_time = tod_to_ns(time);
 
 	/* copy data to new structure */
 	data->ssch_rsch_count = cmb->ssch_rsch_count;
@@ -904,28 +859,27 @@ static int set_cmbe(struct ccw_device *cdev, u32 mme)
 	return set_schib_wait(cdev, mme, 1, mba);
 }
 
-
 static u64 read_cmbe(struct ccw_device *cdev, int index)
 {
-	struct cmbe *cmb;
 	struct cmb_data *cmb_data;
-	u32 val;
-	int ret;
 	unsigned long flags;
-
-	ret = cmf_cmb_copy_wait(cdev);
-	if (ret < 0)
-		return 0;
+	struct cmbe *cmb;
+	u64 ret = 0;
+	u32 val;
 
 	spin_lock_irqsave(cdev->ccwlock, flags);
 	cmb_data = cdev->private->cmb;
-	if (!cmb_data) {
-		ret = 0;
+	if (!cmb_data)
 		goto out;
-	}
-	cmb = cmb_data->last_block;
 
+	cmb = cmb_data->hw_block;
 	switch (index) {
+	case avg_utilization:
+		ret = __cmb_utilization(cmb->device_connect_time,
+					cmb->function_pending_time,
+					cmb->device_disconnect_time,
+					cdev->private->cmb_start_time);
+		goto out;
 	case cmb_ssch_rsch_count:
 		ret = cmb->ssch_rsch_count;
 		goto out;
@@ -954,7 +908,6 @@ static u64 read_cmbe(struct ccw_device *cdev, int index)
 		val = cmb->initial_command_response_time;
 		break;
 	default:
-		ret = 0;
 		goto out;
 	}
 	ret = time_to_avg_nsec(val, cmb->sample_count);
@@ -991,8 +944,7 @@ static int readall_cmbe(struct ccw_device *cdev, struct cmbdata *data)
 	/* we only know values before device_busy_time */
 	data->size = offsetof(struct cmbdata, device_busy_time);
 
-	/* conver to nanoseconds */
-	data->elapsed_time = (time * 1000) >> 12;
+	data->elapsed_time = tod_to_ns(time);
 
 	cmb = cmb_data->last_block;
 	/* copy data to new structure */
@@ -1045,19 +997,15 @@ static ssize_t cmb_show_avg_sample_interval(struct device *dev,
 					    struct device_attribute *attr,
 					    char *buf)
 {
-	struct ccw_device *cdev;
-	long interval;
+	struct ccw_device *cdev = to_ccwdev(dev);
 	unsigned long count;
-	struct cmb_data *cmb_data;
+	long interval;
 
-	cdev = to_ccwdev(dev);
 	count = cmf_read(cdev, cmb_sample_count);
 	spin_lock_irq(cdev->ccwlock);
-	cmb_data = cdev->private->cmb;
 	if (count) {
-		interval = cmb_data->last_update -
-			cdev->private->cmb_start_time;
-		interval = (interval * 1000) >> 12;
+		interval = get_tod_clock() - cdev->private->cmb_start_time;
+		interval = tod_to_ns(interval);
 		interval /= count;
 	} else
 		interval = -1;
@@ -1069,27 +1017,9 @@ static ssize_t cmb_show_avg_utilization(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
 {
-	struct cmbdata data;
-	u64 utilization;
-	unsigned long t, u;
-	int ret;
-
-	ret = cmf_readall(to_ccwdev(dev), &data);
-	if (ret == -EAGAIN || ret == -ENODEV)
-		/* No data (yet/currently) available to use for calculation. */
-		return sprintf(buf, "n/a\n");
-	else if (ret)
-		return ret;
-
-	utilization = data.device_connect_time +
-		      data.function_pending_time +
-		      data.device_disconnect_time;
-
-	/* calculate value in 0.1 percent units */
-	t = data.elapsed_time / 1000;
-	u = utilization / t;
+	unsigned long u = cmf_read(to_ccwdev(dev), avg_utilization);
 
-	return sprintf(buf, "%02ld.%01ld%%\n", u/ 10, u - (u/ 10) * 10);
+	return sprintf(buf, "%02lu.%01lu%%\n", u / 10, u % 10);
 }
 
 #define cmf_attr(name) \
diff --git a/drivers/s390/cio/eadm_sch.c b/drivers/s390/cio/eadm_sch.c
index 0f11f3bcac82..d14795f7110b 100644
--- a/drivers/s390/cio/eadm_sch.c
+++ b/drivers/s390/cio/eadm_sch.c
@@ -43,13 +43,7 @@ static debug_info_t *eadm_debug;
 
 static void EADM_LOG_HEX(int level, void *data, int length)
 {
-	if (!debug_level_enabled(eadm_debug, level))
-		return;
-	while (length > 0) {
-		debug_event(eadm_debug, level, data, length);
-		length -= eadm_debug->buf_size;
-		data += eadm_debug->buf_size;
-	}
+	debug_event(eadm_debug, level, data, length);
 }
 
 static void orb_init(union orb *orb)
diff --git a/drivers/s390/cio/qdio_debug.h b/drivers/s390/cio/qdio_debug.h
index e06496ab0036..f85f5fa7cefc 100644
--- a/drivers/s390/cio/qdio_debug.h
+++ b/drivers/s390/cio/qdio_debug.h
@@ -34,11 +34,7 @@ extern debug_info_t *qdio_dbf_error;
 
 static inline void DBF_HEX(void *addr, int len)
 {
-	while (len > 0) {
-		debug_event(qdio_dbf_setup, DBF_ERR, addr, len);
-		len -= qdio_dbf_setup->buf_size;
-		addr += qdio_dbf_setup->buf_size;
-	}
+	debug_event(qdio_dbf_setup, DBF_ERR, addr, len);
 }
 
 #define DBF_ERROR(text...) \
@@ -50,11 +46,7 @@ static inline void DBF_HEX(void *addr, int len)
 
 static inline void DBF_ERROR_HEX(void *addr, int len)
 {
-	while (len > 0) {
-		debug_event(qdio_dbf_error, DBF_ERR, addr, len);
-		len -= qdio_dbf_error->buf_size;
-		addr += qdio_dbf_error->buf_size;
-	}
+	debug_event(qdio_dbf_error, DBF_ERR, addr, len);
 }
 
 #define DBF_DEV_EVENT(level, device, text...) \
@@ -69,11 +61,7 @@ static inline void DBF_ERROR_HEX(void *addr, int len)
 static inline void DBF_DEV_HEX(struct qdio_irq *dev, void *addr,
 			       int len, int level)
 {
-	while (len > 0) {
-		debug_event(dev->debug_area, level, addr, len);
-		len -= dev->debug_area->buf_size;
-		addr += dev->debug_area->buf_size;
-	}
+	debug_event(dev->debug_area, level, addr, len);
 }
 
 int qdio_allocate_dbf(struct qdio_initialize *init_data,
diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c
index a739bdf9630e..0787b587e4b8 100644
--- a/drivers/s390/cio/qdio_thinint.c
+++ b/drivers/s390/cio/qdio_thinint.c
@@ -57,10 +57,8 @@ static u32 *get_indicator(void)
 	int i;
 
 	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
-		if (!atomic_read(&q_indicators[i].count)) {
-			atomic_set(&q_indicators[i].count, 1);
+		if (!atomic_cmpxchg(&q_indicators[i].count, 0, 1))
 			return &q_indicators[i].ind;
-		}
 
 	/* use the shared indicator */
 	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
@@ -69,13 +67,11 @@ static u32 *get_indicator(void)
 
 static void put_indicator(u32 *addr)
 {
-	int i;
+	struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
 
 	if (!addr)
 		return;
-	i = ((unsigned long)addr - (unsigned long)q_indicators) /
-		sizeof(struct indicator_t);
-	atomic_dec(&q_indicators[i].count);
+	atomic_dec(&ind->count);
 }
 
 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index f20b4d66c75f..d9a2fffd034b 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -106,7 +106,10 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
 {
 	int ret = 0;
 
-	if (!len || pa->pa_nr)
+	if (!len)
+		return 0;
+
+	if (pa->pa_nr)
 		return -EINVAL;
 
 	pa->pa_iova = iova;
@@ -330,6 +333,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
 {
 	struct ccw1 *ccw = chain->ch_ccw + idx;
 
+	if (ccw_is_test(ccw) || ccw_is_noop(ccw) || ccw_is_tic(ccw))
+		return;
 	if (!ccw->count)
 		return;
 
@@ -502,6 +507,16 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 
 	ccw = chain->ch_ccw + idx;
 
+	if (!ccw->count) {
+		/*
+		 * We just want the translation result of any direct ccw
+		 * to be an IDA ccw, so let's add the IDA flag for it.
+		 * Although the flag will be ignored by firmware.
+		 */
+		ccw->flags |= CCW_FLAG_IDA;
+		return 0;
+	}
+
 	/*
 	 * Pin data page(s) in memory.
 	 * The number of pages actually is the count of the idaws which will be
@@ -542,6 +557,9 @@ static int ccwchain_fetch_idal(struct ccwchain *chain,
 
 	ccw = chain->ch_ccw + idx;
 
+	if (!ccw->count)
+		return 0;
+
 	/* Calculate size of idaws. */
 	ret = copy_from_iova(cp->mdev, &idaw_iova, ccw->cda, sizeof(idaw_iova));
 	if (ret)
@@ -570,10 +588,6 @@ static int ccwchain_fetch_idal(struct ccwchain *chain,
 
 	for (i = 0; i < idaw_nr; i++) {
 		idaw_iova = *(idaws + i);
-		if (IS_ERR_VALUE(idaw_iova)) {
-			ret = -EFAULT;
-			goto out_free_idaws;
-		}
 
 		ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev,
 					  idaw_iova, 1);