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 9978ad4433cb..5ac9c935c151 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 3c1ccf494647..8b387b32fd62 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 9fa0a908607b..5f6180d6ff08 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 30a2255389e5..cd798386b622 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 31ceef1beb8b..e16c553f6556 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 227e05f674b3..349d5fc47196 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 bcf20f3aa51b..46ec25632e8b 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 d87961d4c0de..8c0622399fcd 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 0d8cdff81813..0d73a999983d 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 091ca0efa1c5..8710337dab3e 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 ebc379486267..e70af2406ff9 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;
 }