Merge tag 'for-linus-20180929' of git://git.kernel.dk/linux-block

Jens writes:
  "Block fixes for 4.19-rc6

   A set of fixes that should go into this release. This pull request
   contains:

   - A fix (hopefully) for the persistent grants for xen-blkfront. A
     previous fix from this series wasn't complete, hence reverted, and
     this one should hopefully be it. (Boris Ostrovsky)

   - Fix for an elevator drain warning with SMR devices, which is
     triggered when you switch schedulers (Damien)

   - bcache deadlock fix (Guoju Fang)

   - Fix for the block unplug tracepoint, which has had the
     timer/explicit flag reverted since 4.11 (Ilya)

   - Fix a regression in this series where the blk-mq timeout hook is
     invoked with the RCU read lock held, hence preventing it from
     blocking (Keith)

   - NVMe pull from Christoph, with a single multipath fix (Susobhan Dey)"

* tag 'for-linus-20180929' of git://git.kernel.dk/linux-block:
  xen/blkfront: correct purging of persistent grants
  Revert "xen/blkfront: When purging persistent grants, keep them in the buffer"
  blk-mq: I/O and timer unplugs are inverted in blktrace
  bcache: add separate workqueue for journal_write to avoid deadlock
  xen/blkfront: When purging persistent grants, keep them in the buffer
  block: fix deadline elevator drain for zoned block devices
  blk-mq: Allow blocking queue tag iter callbacks
  nvme: properly propagate errors in nvme_mpath_init

8 files changed, 25 insertions, 19 deletions

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 94e1ed667b6e..41317c50a446 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -322,16 +322,11 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 
         /*
          * __blk_mq_update_nr_hw_queues will update the nr_hw_queues and
-         * queue_hw_ctx after freeze the queue. So we could use q_usage_counter
-         * to avoid race with it. __blk_mq_update_nr_hw_queues will users
-         * synchronize_rcu to ensure all of the users go out of the critical
-         * section below and see zeroed q_usage_counter.
+         * queue_hw_ctx after freeze the queue, so we use q_usage_counter
+         * to avoid race with it.
          */
-        rcu_read_lock();
-        if (percpu_ref_is_zero(&q->q_usage_counter)) {
-                rcu_read_unlock();
+        if (!percpu_ref_tryget(&q->q_usage_counter))
                 return;
-        }
 
         queue_for_each_hw_ctx(q, hctx, i) {
                 struct blk_mq_tags *tags = hctx->tags;
@@ -347,7 +342,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
                         bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
                 bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
         }
-        rcu_read_unlock();
+        blk_queue_exit(q);
 }
 
 static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 85a1c1a59c72..e3c39ea8e17b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1628,7 +1628,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
                 BUG_ON(!rq->q);
                 if (rq->mq_ctx != this_ctx) {
                         if (this_ctx) {
-                                trace_block_unplug(this_q, depth, from_schedule);
+                                trace_block_unplug(this_q, depth, !from_schedule);
                                 blk_mq_sched_insert_requests(this_q, this_ctx,
                                                                 &ctx_list,
                                                                 from_schedule);
@@ -1648,7 +1648,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
          * on 'ctx_list'. Do those.
          */
         if (this_ctx) {
-                trace_block_unplug(this_q, depth, from_schedule);
+                trace_block_unplug(this_q, depth, !from_schedule);
                 blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list,
                                                 from_schedule);
         }
diff --git a/block/elevator.c b/block/elevator.c
index 6a06b5d040e5..fae58b2f906f 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -609,7 +609,7 @@ void elv_drain_elevator(struct request_queue *q)
 
         while (e->type->ops.sq.elevator_dispatch_fn(q, 1))
                 ;
-        if (q->nr_sorted && printed++ < 10) {
+        if (q->nr_sorted && !blk_queue_is_zoned(q) && printed++ < 10 ) {
                 printk(KERN_ERR "%s: forced dispatching is broken "
                        "(nr_sorted=%u), please report this\n",
                        q->elevator->type->elevator_name, q->nr_sorted);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index a71d817e900d..429d20131c7e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2670,8 +2670,8 @@ static void purge_persistent_grants(struct blkfront_info *info)
                         list_del(&gnt_list_entry->node);
                         gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL);
                         rinfo->persistent_gnts_c--;
-                        __free_page(gnt_list_entry->page);
-                        kfree(gnt_list_entry);
+                        gnt_list_entry->gref = GRANT_INVALID_REF;
+                        list_add_tail(&gnt_list_entry->node, &rinfo->grants);
                 }
 
                 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 83504dd8100a..954dad29e6e8 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -965,6 +965,7 @@ void bch_prio_write(struct cache *ca);
 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent);
 
 extern struct workqueue_struct *bcache_wq;
+extern struct workqueue_struct *bch_journal_wq;
 extern struct mutex bch_register_lock;
 extern struct list_head bch_cache_sets;
 
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index 6116bbf870d8..522c7426f3a0 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -485,7 +485,7 @@ static void do_journal_discard(struct cache *ca)
 
                 closure_get(&ca->set->cl);
                 INIT_WORK(&ja->discard_work, journal_discard_work);
-                schedule_work(&ja->discard_work);
+                queue_work(bch_journal_wq, &ja->discard_work);
         }
 }
 
@@ -592,7 +592,7 @@ static void journal_write_done(struct closure *cl)
                 : &j->w[0];
 
         __closure_wake_up(&w->wait);
-        continue_at_nobarrier(cl, journal_write, system_wq);
+        continue_at_nobarrier(cl, journal_write, bch_journal_wq);
 }
 
 static void journal_write_unlock(struct closure *cl)
@@ -627,7 +627,7 @@ static void journal_write_unlocked(struct closure *cl)
                 spin_unlock(&c->journal.lock);
 
                 btree_flush_write(c);
-                continue_at(cl, journal_write, system_wq);
+                continue_at(cl, journal_write, bch_journal_wq);
                 return;
         }
 
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 94c756c66bd7..30ba9aeb5ee8 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -47,6 +47,7 @@ static int bcache_major;
 static DEFINE_IDA(bcache_device_idx);
 static wait_queue_head_t unregister_wait;
 struct workqueue_struct *bcache_wq;
+struct workqueue_struct *bch_journal_wq;
 
 #define BTREE_MAX_PAGES         (256 * 1024 / PAGE_SIZE)
 /* limitation of partitions number on single bcache device */
@@ -2341,6 +2342,9 @@ static void bcache_exit(void)
                 kobject_put(bcache_kobj);
         if (bcache_wq)
                 destroy_workqueue(bcache_wq);
+        if (bch_journal_wq)
+                destroy_workqueue(bch_journal_wq);
+
         if (bcache_major)
                 unregister_blkdev(bcache_major, "bcache");
         unregister_reboot_notifier(&reboot);
@@ -2370,6 +2374,10 @@ static int __init bcache_init(void)
         if (!bcache_wq)
                 goto err;
 
+        bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
+        if (!bch_journal_wq)
+                goto err;
+
         bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
         if (!bcache_kobj)
                 goto err;
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 5a9562881d4e..9fe3fff818b8 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -537,8 +537,10 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 
         INIT_WORK(&ctrl->ana_work, nvme_ana_work);
         ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
-        if (!ctrl->ana_log_buf)
+        if (!ctrl->ana_log_buf) {
+                error = -ENOMEM;
                 goto out;
+        }
 
         error = nvme_read_ana_log(ctrl, true);
         if (error)
@@ -547,7 +549,7 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 out_free_ana_log_buf:
         kfree(ctrl->ana_log_buf);
 out:
-        return -ENOMEM;
+        return error;
 }
 
 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)