Merge branch 'writeback-workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into for-3.10/core

Tejun writes:

-----

This is the pull request for the earlier patchset[1] with the same
name.  It's only three patches (the first one was committed to
workqueue tree) but the merge strategy is a bit involved due to the
dependencies.

* Because the conversion needs features from wq/for-3.10,
  block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts
  with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those
  workqueue conflicts from flaring up in block tree.

* Resolving the issue that Jan and Dave raised about debugging
  requires arch-wide changes.  The patchset is being worked on[2] but
  it'll have to go through -mm after these changes show up in -next,
  and not included in this pull request.

The three commits are located in the following git branch.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue

Pulling it into block/for-3.10/core produces a conflict in
drivers/md/raid5.c between the following two commits.

  e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available")
  2f6db2a707 ("raid5: use bio_reset()")

The conflict is trivial - one removes an "if ()" conditional while the
other removes "rbi->bi_next = NULL" right above it.  We just need to
remove both.  The merged branch is available at

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge

so that you can use it for verification.  The test merge commit has
proper merge description.

While these changes are a bit of pain to route, they make code simpler
and even have, while minute, measureable performance gain[3] even on a
workload which isn't particularly favorable to showing the benefits of
this conversion.

----

Fixed up the conflict.

Conflicts:
	drivers/md/raid5.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>

11 files changed, 175 insertions, 29 deletions

diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index 9978ad4..5ac9c93 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -135,6 +135,11 @@ static const struct block_device_operations scm_blk_devops = {
 	.release = scm_release,
 };
 
+static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req)
+{
+	return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT;
+}
+
 static void scm_request_prepare(struct scm_request *scmrq)
 {
 	struct scm_blk_dev *bdev = scmrq->bdev;
@@ -195,14 +200,18 @@ void scm_request_requeue(struct scm_request *scmrq)
 
 	scm_release_cluster(scmrq);
 	blk_requeue_request(bdev->rq, scmrq->request);
+	atomic_dec(&bdev->queued_reqs);
 	scm_request_done(scmrq);
 	scm_ensure_queue_restart(bdev);
 }
 
 void scm_request_finish(struct scm_request *scmrq)
 {
+	struct scm_blk_dev *bdev = scmrq->bdev;
+
 	scm_release_cluster(scmrq);
 	blk_end_request_all(scmrq->request, scmrq->error);
+	atomic_dec(&bdev->queued_reqs);
 	scm_request_done(scmrq);
 }
 
@@ -218,6 +227,10 @@ static void scm_blk_request(struct request_queue *rq)
 		if (req->cmd_type != REQ_TYPE_FS)
 			continue;
 
+		if (!scm_permit_request(bdev, req)) {
+			scm_ensure_queue_restart(bdev);
+			return;
+		}
 		scmrq = scm_request_fetch();
 		if (!scmrq) {
 			SCM_LOG(5, "no request");
@@ -231,11 +244,13 @@ static void scm_blk_request(struct request_queue *rq)
 			return;
 		}
 		if (scm_need_cluster_request(scmrq)) {
+			atomic_inc(&bdev->queued_reqs);
 			blk_start_request(req);
 			scm_initiate_cluster_request(scmrq);
 			return;
 		}
 		scm_request_prepare(scmrq);
+		atomic_inc(&bdev->queued_reqs);
 		blk_start_request(req);
 
 		ret = scm_start_aob(scmrq->aob);
@@ -244,7 +259,6 @@ static void scm_blk_request(struct request_queue *rq)
 			scm_request_requeue(scmrq);
 			return;
 		}
-		atomic_inc(&bdev->queued_reqs);
 	}
 }
 
@@ -280,6 +294,38 @@ void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
 	tasklet_hi_schedule(&bdev->tasklet);
 }
 
+static void scm_blk_handle_error(struct scm_request *scmrq)
+{
+	struct scm_blk_dev *bdev = scmrq->bdev;
+	unsigned long flags;
+
+	if (scmrq->error != -EIO)
+		goto restart;
+
+	/* For -EIO the response block is valid. */
+	switch (scmrq->aob->response.eqc) {
+	case EQC_WR_PROHIBIT:
+		spin_lock_irqsave(&bdev->lock, flags);
+		if (bdev->state != SCM_WR_PROHIBIT)
+			pr_info("%lu: Write access to the SCM increment is suspended\n",
+				(unsigned long) bdev->scmdev->address);
+		bdev->state = SCM_WR_PROHIBIT;
+		spin_unlock_irqrestore(&bdev->lock, flags);
+		goto requeue;
+	default:
+		break;
+	}
+
+restart:
+	if (!scm_start_aob(scmrq->aob))
+		return;
+
+requeue:
+	spin_lock_irqsave(&bdev->rq_lock, flags);
+	scm_request_requeue(scmrq);
+	spin_unlock_irqrestore(&bdev->rq_lock, flags);
+}
+
 static void scm_blk_tasklet(struct scm_blk_dev *bdev)
 {
 	struct scm_request *scmrq;
@@ -293,11 +339,8 @@ static void scm_blk_tasklet(struct scm_blk_dev *bdev)
 		spin_unlock_irqrestore(&bdev->lock, flags);
 
 		if (scmrq->error && scmrq->retries-- > 0) {
-			if (scm_start_aob(scmrq->aob)) {
-				spin_lock_irqsave(&bdev->rq_lock, flags);
-				scm_request_requeue(scmrq);
-				spin_unlock_irqrestore(&bdev->rq_lock, flags);
-			}
+			scm_blk_handle_error(scmrq);
+
 			/* Request restarted or requeued, handle next. */
 			spin_lock_irqsave(&bdev->lock, flags);
 			continue;
@@ -310,7 +353,6 @@ static void scm_blk_tasklet(struct scm_blk_dev *bdev)
 		}
 
 		scm_request_finish(scmrq);
-		atomic_dec(&bdev->queued_reqs);
 		spin_lock_irqsave(&bdev->lock, flags);
 	}
 	spin_unlock_irqrestore(&bdev->lock, flags);
@@ -332,6 +374,7 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 	}
 
 	bdev->scmdev = scmdev;
+	bdev->state = SCM_OPER;
 	spin_lock_init(&bdev->rq_lock);
 	spin_lock_init(&bdev->lock);
 	INIT_LIST_HEAD(&bdev->finished_requests);
@@ -396,6 +439,18 @@ void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
 	put_disk(bdev->gendisk);
 }
 
+void scm_blk_set_available(struct scm_blk_dev *bdev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&bdev->lock, flags);
+	if (bdev->state == SCM_WR_PROHIBIT)
+		pr_info("%lu: Write access to the SCM increment is restored\n",
+			(unsigned long) bdev->scmdev->address);
+	bdev->state = SCM_OPER;
+	spin_unlock_irqrestore(&bdev->lock, flags);
+}
+
 static int __init scm_blk_init(void)
 {
 	int ret = -EINVAL;
diff --git a/drivers/s390/block/scm_blk.h b/drivers/s390/block/scm_blk.h
index 3c1ccf4..8b387b3 100644
--- a/drivers/s390/block/scm_blk.h
+++ b/drivers/s390/block/scm_blk.h
@@ -21,6 +21,7 @@ struct scm_blk_dev {
 	spinlock_t rq_lock;	/* guard the request queue */
 	spinlock_t lock;	/* guard the rest of the blockdev */
 	atomic_t queued_reqs;
+	enum {SCM_OPER, SCM_WR_PROHIBIT} state;
 	struct list_head finished_requests;
 #ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE
 	struct list_head cluster_list;
@@ -48,6 +49,7 @@ struct scm_request {
 
 int scm_blk_dev_setup(struct scm_blk_dev *, struct scm_device *);
 void scm_blk_dev_cleanup(struct scm_blk_dev *);
+void scm_blk_set_available(struct scm_blk_dev *);
 void scm_blk_irq(struct scm_device *, void *, int);
 
 void scm_request_finish(struct scm_request *);
diff --git a/drivers/s390/block/scm_drv.c b/drivers/s390/block/scm_drv.c
index 9fa0a90..5f6180d 100644
--- a/drivers/s390/block/scm_drv.c
+++ b/drivers/s390/block/scm_drv.c
@@ -13,12 +13,23 @@
 #include <asm/eadm.h>
 #include "scm_blk.h"
 
-static void notify(struct scm_device *scmdev)
+static void scm_notify(struct scm_device *scmdev, enum scm_event event)
 {
-	pr_info("%lu: The capabilities of the SCM increment changed\n",
-		(unsigned long) scmdev->address);
-	SCM_LOG(2, "State changed");
-	SCM_LOG_STATE(2, scmdev);
+	struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
+
+	switch (event) {
+	case SCM_CHANGE:
+		pr_info("%lu: The capabilities of the SCM increment changed\n",
+			(unsigned long) scmdev->address);
+		SCM_LOG(2, "State changed");
+		SCM_LOG_STATE(2, scmdev);
+		break;
+	case SCM_AVAIL:
+		SCM_LOG(2, "Increment available");
+		SCM_LOG_STATE(2, scmdev);
+		scm_blk_set_available(bdev);
+		break;
+	}
 }
 
 static int scm_probe(struct scm_device *scmdev)
@@ -64,7 +75,7 @@ static struct scm_driver scm_drv = {
 		.name = "scm_block",
 		.owner = THIS_MODULE,
 	},
-	.notify = notify,
+	.notify = scm_notify,
 	.probe = scm_probe,
 	.remove = scm_remove,
 	.handler = scm_blk_irq,
diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 30a2255..cd79838 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -627,6 +627,8 @@ static int __init sclp_detect_standby_memory(void)
 	struct read_storage_sccb *sccb;
 	int i, id, assigned, rc;
 
+	if (OLDMEM_BASE) /* No standby memory in kdump mode */
+		return 0;
 	if (!early_read_info_sccb_valid)
 		return 0;
 	if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 31ceef1..e16c553 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -433,6 +433,20 @@ static void chsc_process_sei_scm_change(struct chsc_sei_nt0_area *sei_area)
 			      " failed (rc=%d).\n", ret);
 }
 
+static void chsc_process_sei_scm_avail(struct chsc_sei_nt0_area *sei_area)
+{
+	int ret;
+
+	CIO_CRW_EVENT(4, "chsc: scm available information\n");
+	if (sei_area->rs != 7)
+		return;
+
+	ret = scm_process_availability_information();
+	if (ret)
+		CIO_CRW_EVENT(0, "chsc: process availability information"
+			      " failed (rc=%d).\n", ret);
+}
+
 static void chsc_process_sei_nt2(struct chsc_sei_nt2_area *sei_area)
 {
 	switch (sei_area->cc) {
@@ -468,6 +482,9 @@ static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
 	case 12: /* scm change notification */
 		chsc_process_sei_scm_change(sei_area);
 		break;
+	case 14: /* scm available notification */
+		chsc_process_sei_scm_avail(sei_area);
+		break;
 	default: /* other stuff */
 		CIO_CRW_EVENT(2, "chsc: sei nt0 unhandled cc=%d\n",
 			      sei_area->cc);
diff --git a/drivers/s390/cio/chsc.h b/drivers/s390/cio/chsc.h
index 227e05f..349d5fc 100644
--- a/drivers/s390/cio/chsc.h
+++ b/drivers/s390/cio/chsc.h
@@ -156,8 +156,10 @@ int chsc_scm_info(struct chsc_scm_info *scm_area, u64 token);
 
 #ifdef CONFIG_SCM_BUS
 int scm_update_information(void);
+int scm_process_availability_information(void);
 #else /* CONFIG_SCM_BUS */
 static inline int scm_update_information(void) { return 0; }
+static inline int scm_process_availability_information(void) { return 0; }
 #endif /* CONFIG_SCM_BUS */
 
 
diff --git a/drivers/s390/cio/scm.c b/drivers/s390/cio/scm.c
index bcf20f3..46ec256 100644
--- a/drivers/s390/cio/scm.c
+++ b/drivers/s390/cio/scm.c
@@ -211,7 +211,7 @@ static void scmdev_update(struct scm_device *scmdev, struct sale *sale)
 		goto out;
 	scmdrv = to_scm_drv(scmdev->dev.driver);
 	if (changed && scmdrv->notify)
-		scmdrv->notify(scmdev);
+		scmdrv->notify(scmdev, SCM_CHANGE);
 out:
 	device_unlock(&scmdev->dev);
 	if (changed)
@@ -297,6 +297,22 @@ int scm_update_information(void)
 	return ret;
 }
 
+static int scm_dev_avail(struct device *dev, void *unused)
+{
+	struct scm_driver *scmdrv = to_scm_drv(dev->driver);
+	struct scm_device *scmdev = to_scm_dev(dev);
+
+	if (dev->driver && scmdrv->notify)
+		scmdrv->notify(scmdev, SCM_AVAIL);
+
+	return 0;
+}
+
+int scm_process_availability_information(void)
+{
+	return bus_for_each_dev(&scm_bus_type, NULL, NULL, scm_dev_avail);
+}
+
 static int __init scm_init(void)
 {
 	int ret;
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index d87961d..8c06223 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -916,6 +916,7 @@ int qeth_send_control_data(struct qeth_card *, int, struct qeth_cmd_buffer *,
 	void *reply_param);
 int qeth_get_priority_queue(struct qeth_card *, struct sk_buff *, int, int);
 int qeth_get_elements_no(struct qeth_card *, void *, struct sk_buff *, int);
+int qeth_get_elements_for_frags(struct sk_buff *);
 int qeth_do_send_packet_fast(struct qeth_card *, struct qeth_qdio_out_q *,
 			struct sk_buff *, struct qeth_hdr *, int, int, int);
 int qeth_do_send_packet(struct qeth_card *, struct qeth_qdio_out_q *,
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 0d8cdff..0d73a99 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -3679,6 +3679,25 @@ int qeth_get_priority_queue(struct qeth_card *card, struct sk_buff *skb,
 }
 EXPORT_SYMBOL_GPL(qeth_get_priority_queue);
 
+int qeth_get_elements_for_frags(struct sk_buff *skb)
+{
+	int cnt, length, e, elements = 0;
+	struct skb_frag_struct *frag;
+	char *data;
+
+	for (cnt = 0; cnt < skb_shinfo(skb)->nr_frags; cnt++) {
+		frag = &skb_shinfo(skb)->frags[cnt];
+		data = (char *)page_to_phys(skb_frag_page(frag)) +
+			frag->page_offset;
+		length = frag->size;
+		e = PFN_UP((unsigned long)data + length - 1) -
+			PFN_DOWN((unsigned long)data);
+		elements += e;
+	}
+	return elements;
+}
+EXPORT_SYMBOL_GPL(qeth_get_elements_for_frags);
+
 int qeth_get_elements_no(struct qeth_card *card, void *hdr,
 		     struct sk_buff *skb, int elems)
 {
@@ -3686,7 +3705,8 @@ int qeth_get_elements_no(struct qeth_card *card, void *hdr,
 	int elements_needed = PFN_UP((unsigned long)skb->data + dlen - 1) -
 		PFN_DOWN((unsigned long)skb->data);
 
-	elements_needed += skb_shinfo(skb)->nr_frags;
+	elements_needed += qeth_get_elements_for_frags(skb);
+
 	if ((elements_needed + elems) > QETH_MAX_BUFFER_ELEMENTS(card)) {
 		QETH_DBF_MESSAGE(2, "Invalid size of IP packet "
 			"(Number=%d / Length=%d). Discarded.\n",
@@ -3771,12 +3791,23 @@ static inline void __qeth_fill_buffer(struct sk_buff *skb,
 
 	for (cnt = 0; cnt < skb_shinfo(skb)->nr_frags; cnt++) {
 		frag = &skb_shinfo(skb)->frags[cnt];
-		buffer->element[element].addr = (char *)
-			page_to_phys(skb_frag_page(frag))
-			+ frag->page_offset;
-		buffer->element[element].length = frag->size;
-		buffer->element[element].eflags = SBAL_EFLAGS_MIDDLE_FRAG;
-		element++;
+		data = (char *)page_to_phys(skb_frag_page(frag)) +
+			frag->page_offset;
+		length = frag->size;
+		while (length > 0) {
+			length_here = PAGE_SIZE -
+				((unsigned long) data % PAGE_SIZE);
+			if (length < length_here)
+				length_here = length;
+
+			buffer->element[element].addr = data;
+			buffer->element[element].length = length_here;
+			buffer->element[element].eflags =
+				SBAL_EFLAGS_MIDDLE_FRAG;
+			length -= length_here;
+			data += length_here;
+			element++;
+		}
 	}
 
 	if (buffer->element[element - 1].eflags)
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 091ca0efa..8710337 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -623,7 +623,7 @@ static int qeth_l3_send_setrouting(struct qeth_card *card,
 	return rc;
 }
 
-static void qeth_l3_correct_routing_type(struct qeth_card *card,
+static int qeth_l3_correct_routing_type(struct qeth_card *card,
 		enum qeth_routing_types *type, enum qeth_prot_versions prot)
 {
 	if (card->info.type == QETH_CARD_TYPE_IQD) {
@@ -632,7 +632,7 @@ static void qeth_l3_correct_routing_type(struct qeth_card *card,
 		case PRIMARY_CONNECTOR:
 		case SECONDARY_CONNECTOR:
 		case MULTICAST_ROUTER:
-			return;
+			return 0;
 		default:
 			goto out_inval;
 		}
@@ -641,17 +641,18 @@ static void qeth_l3_correct_routing_type(struct qeth_card *card,
 		case NO_ROUTER:
 		case PRIMARY_ROUTER:
 		case SECONDARY_ROUTER:
-			return;
+			return 0;
 		case MULTICAST_ROUTER:
 			if (qeth_is_ipafunc_supported(card, prot,
 						      IPA_OSA_MC_ROUTER))
-				return;
+				return 0;
 		default:
 			goto out_inval;
 		}
 	}
 out_inval:
 	*type = NO_ROUTER;
+	return -EINVAL;
 }
 
 int qeth_l3_setrouting_v4(struct qeth_card *card)
@@ -660,8 +661,10 @@ int qeth_l3_setrouting_v4(struct qeth_card *card)
 
 	QETH_CARD_TEXT(card, 3, "setrtg4");
 
-	qeth_l3_correct_routing_type(card, &card->options.route4.type,
+	rc = qeth_l3_correct_routing_type(card, &card->options.route4.type,
 				  QETH_PROT_IPV4);
+	if (rc)
+		return rc;
 
 	rc = qeth_l3_send_setrouting(card, card->options.route4.type,
 				  QETH_PROT_IPV4);
@@ -683,8 +686,10 @@ int qeth_l3_setrouting_v6(struct qeth_card *card)
 
 	if (!qeth_is_supported(card, IPA_IPV6))
 		return 0;
-	qeth_l3_correct_routing_type(card, &card->options.route6.type,
+	rc = qeth_l3_correct_routing_type(card, &card->options.route6.type,
 				  QETH_PROT_IPV6);
+	if (rc)
+		return rc;
 
 	rc = qeth_l3_send_setrouting(card, card->options.route6.type,
 				  QETH_PROT_IPV6);
@@ -2898,7 +2903,9 @@ static inline int qeth_l3_tso_elements(struct sk_buff *skb)
 		tcp_hdr(skb)->doff * 4;
 	int tcpd_len = skb->len - (tcpd - (unsigned long)skb->data);
 	int elements = PFN_UP(tcpd + tcpd_len - 1) - PFN_DOWN(tcpd);
-	elements += skb_shinfo(skb)->nr_frags;
+
+	elements += qeth_get_elements_for_frags(skb);
+
 	return elements;
 }
 
@@ -3348,7 +3355,6 @@ static int __qeth_l3_set_online(struct ccwgroup_device *gdev, int recovery_mode)
 		rc = -ENODEV;
 		goto out_remove;
 	}
-	qeth_trace_features(card);
 
 	if (!card->dev && qeth_l3_setup_netdev(card)) {
 		rc = -ENODEV;
@@ -3425,6 +3431,7 @@ contin:
 		qeth_l3_set_multicast_list(card->dev);
 		rtnl_unlock();
 	}
+	qeth_trace_features(card);
 	/* let user_space know that device is online */
 	kobject_uevent(&gdev->dev.kobj, KOBJ_CHANGE);
 	mutex_unlock(&card->conf_mutex);
diff --git a/drivers/s390/net/qeth_l3_sys.c b/drivers/s390/net/qeth_l3_sys.c
index ebc3794..e70af24 100644
--- a/drivers/s390/net/qeth_l3_sys.c
+++ b/drivers/s390/net/qeth_l3_sys.c
@@ -87,6 +87,8 @@ static ssize_t qeth_l3_dev_route_store(struct qeth_card *card,
 			rc = qeth_l3_setrouting_v6(card);
 	}
 out:
+	if (rc)
+		route->type = old_route_type;
 	mutex_unlock(&card->conf_mutex);
 	return rc ? rc : count;
 }