Merge tag 'for-linus-2019-08-17' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A collection of fixes that should go into this series. This contains:

   - Revert of the REQ_NOWAIT_INLINE and associated dio changes. There
     were still corner cases there, and even though I had a solution for
     it, it's too involved for this stage. (me)

   - Set of NVMe fixes (via Sagi)

   - io_uring fix for fixed buffers (Anthony)

   - io_uring defer issue fix (Jackie)

   - Regression fix for queue sync at exit time (zhengbin)

   - xen blk-back memory leak fix (Wenwen)"

* tag 'for-linus-2019-08-17' of git://git.kernel.dk/linux-block:
  io_uring: fix an issue when IOSQE_IO_LINK is inserted into defer list
  block: remove REQ_NOWAIT_INLINE
  io_uring: fix manual setup of iov_iter for fixed buffers
  xen/blkback: fix memory leaks
  blk-mq: move cancel of requeue_work to the front of blk_exit_queue
  nvme-pci: Fix async probe remove race
  nvme: fix controller removal race with scan work
  nvme-rdma: fix possible use-after-free in connect error flow
  nvme: fix a possible deadlock when passthru commands sent to a multipath device
  nvme-core: Fix extra device_put() call on error path
  nvmet-file: fix nvmet_file_flush() always returning an error
  nvmet-loop: Flush nvme_delete_wq when removing the port
  nvmet: Fix use-after-free bug when a port is removed
  nvme-multipath: revalidate nvme_ns_head gendisk in nvme_validate_ns

block/blk-mq.c

@@ -1958,13 +1958,9 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 	rq = blk_mq_get_request(q, bio, &data);
 	if (unlikely(!rq)) {
 		rq_qos_cleanup(q, bio);
-
-		cookie = BLK_QC_T_NONE;
-		if (bio->bi_opf & REQ_NOWAIT_INLINE)
-			cookie = BLK_QC_T_EAGAIN;
-		else if (bio->bi_opf & REQ_NOWAIT)
+		if (bio->bi_opf & REQ_NOWAIT)
 			bio_wouldblock_error(bio);
-		return cookie;
+		return BLK_QC_T_NONE;
 	}
 
 	trace_block_getrq(q, bio, bio->bi_opf);
@@ -2666,8 +2662,6 @@ void blk_mq_release(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx, *next;
 	int i;
 
-	cancel_delayed_work_sync(&q->requeue_work);
-
 	queue_for_each_hw_ctx(q, hctx, i)
 		WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
 

block/blk-sysfs.c

@@ -892,6 +892,9 @@ static void __blk_release_queue(struct work_struct *work)
 
 	blk_free_queue_stats(q->stats);
 
+	if (queue_is_mq(q))
+		cancel_delayed_work_sync(&q->requeue_work);
+
 	blk_exit_queue(q);
 
 	blk_queue_free_zone_bitmaps(q);

drivers/block/xen-blkback/xenbus.c

@@ -965,6 +965,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
 		}
 	}
 
+	err = -ENOMEM;
 	for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) {
 		req = kzalloc(sizeof(*req), GFP_KERNEL);
 		if (!req)
@@ -987,7 +988,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
 	err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn);
-		return err;
+		goto fail;
 	}
 
 	return 0;
@@ -1007,8 +1008,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
 		}
 		kfree(req);
 	}
-	return -ENOMEM;
-
+	return err;
 }
 
 static int connect_ring(struct backend_info *be)

drivers/nvme/host/core.c

@@ -1286,6 +1286,9 @@ static u32 nvme_passthru_start(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 	 */
 	if (effects & (NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK)) {
 		mutex_lock(&ctrl->scan_lock);
+		mutex_lock(&ctrl->subsys->lock);
+		nvme_mpath_start_freeze(ctrl->subsys);
+		nvme_mpath_wait_freeze(ctrl->subsys);
 		nvme_start_freeze(ctrl);
 		nvme_wait_freeze(ctrl);
 	}
@@ -1316,6 +1319,8 @@ static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
 		nvme_update_formats(ctrl);
 	if (effects & (NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK)) {
 		nvme_unfreeze(ctrl);
+		nvme_mpath_unfreeze(ctrl->subsys);
+		mutex_unlock(&ctrl->subsys->lock);
 		mutex_unlock(&ctrl->scan_lock);
 	}
 	if (effects & NVME_CMD_EFFECTS_CCC)
@@ -1715,6 +1720,7 @@ static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id)
 	if (ns->head->disk) {
 		nvme_update_disk_info(ns->head->disk, ns, id);
 		blk_queue_stack_limits(ns->head->disk->queue, ns->queue);
+		revalidate_disk(ns->head->disk);
 	}
 #endif
 }
@@ -2487,6 +2493,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 		if (ret) {
 			dev_err(ctrl->device,
 				"failed to register subsystem device.\n");
+			put_device(&subsys->dev);
 			goto out_unlock;
 		}
 		ida_init(&subsys->ns_ida);
@@ -2509,7 +2516,6 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	nvme_put_subsystem(subsys);
 out_unlock:
 	mutex_unlock(&nvme_subsystems_lock);
-	put_device(&subsys->dev);
 	return ret;
 }
 
@@ -3571,6 +3577,13 @@ void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
 	struct nvme_ns *ns, *next;
 	LIST_HEAD(ns_list);
 
+	/*
+	 * make sure to requeue I/O to all namespaces as these
+	 * might result from the scan itself and must complete
+	 * for the scan_work to make progress
+	 */
+	nvme_mpath_clear_ctrl_paths(ctrl);
+
 	/* prevent racing with ns scanning */
 	flush_work(&ctrl->scan_work);
 

drivers/nvme/host/multipath.c

@@ -12,6 +12,36 @@ module_param(multipath, bool, 0444);
 MODULE_PARM_DESC(multipath,
 	"turn on native support for multiple controllers per subsystem");
 
+void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_mq_unfreeze_queue(h->disk->queue);
+}
+
+void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_mq_freeze_queue_wait(h->disk->queue);
+}
+
+void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_freeze_queue_start(h->disk->queue);
+}
+
 /*
  * If multipathing is enabled we need to always use the subsystem instance
  * number for numbering our devices to avoid conflicts between subsystems that
@@ -104,18 +134,34 @@ static const char *nvme_ana_state_names[] = {
 	[NVME_ANA_CHANGE]		= "change",
 };
 
-void nvme_mpath_clear_current_path(struct nvme_ns *ns)
+bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
 {
 	struct nvme_ns_head *head = ns->head;
+	bool changed = false;
 	int node;
 
 	if (!head)
-		return;
+		goto out;
 
 	for_each_node(node) {
-		if (ns == rcu_access_pointer(head->current_path[node]))
+		if (ns == rcu_access_pointer(head->current_path[node])) {
 			rcu_assign_pointer(head->current_path[node], NULL);
+			changed = true;
 		}
+	}
+out:
+	return changed;
+}
+
+void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
+{
+	struct nvme_ns *ns;
+
+	mutex_lock(&ctrl->scan_lock);
+	list_for_each_entry(ns, &ctrl->namespaces, list)
+		if (nvme_mpath_clear_current_path(ns))
+			kblockd_schedule_work(&ns->head->requeue_work);
+	mutex_unlock(&ctrl->scan_lock);
 }
 
 static bool nvme_path_is_disabled(struct nvme_ns *ns)
@@ -226,6 +272,24 @@ inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
 	return ns;
 }
 
+static bool nvme_available_path(struct nvme_ns_head *head)
+{
+	struct nvme_ns *ns;
+
+	list_for_each_entry_rcu(ns, &head->list, siblings) {
+		switch (ns->ctrl->state) {
+		case NVME_CTRL_LIVE:
+		case NVME_CTRL_RESETTING:
+		case NVME_CTRL_CONNECTING:
+			/* fallthru */
+			return true;
+		default:
+			break;
+		}
+	}
+	return false;
+}
+
 static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
 		struct bio *bio)
 {
@@ -252,14 +316,14 @@ static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
 				      disk_devt(ns->head->disk),
 				      bio->bi_iter.bi_sector);
 		ret = direct_make_request(bio);
-	} else if (!list_empty_careful(&head->list)) {
-		dev_warn_ratelimited(dev, "no path available - requeuing I/O\n");
+	} else if (nvme_available_path(head)) {
+		dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
 
 		spin_lock_irq(&head->requeue_lock);
 		bio_list_add(&head->requeue_list, bio);
 		spin_unlock_irq(&head->requeue_lock);
 	} else {
-		dev_warn_ratelimited(dev, "no path - failing I/O\n");
+		dev_warn_ratelimited(dev, "no available path - failing I/O\n");
 
 		bio->bi_status = BLK_STS_IOERR;
 		bio_endio(bio);

drivers/nvme/host/nvme.h

@@ -490,6 +490,9 @@ static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
 	return ctrl->ana_log_buf != NULL;
 }
 
+void nvme_mpath_unfreeze(struct nvme_subsystem *subsys);
+void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys);
+void nvme_mpath_start_freeze(struct nvme_subsystem *subsys);
 void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
 			struct nvme_ctrl *ctrl, int *flags);
 void nvme_failover_req(struct request *req);
@@ -500,7 +503,8 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head);
 int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id);
 void nvme_mpath_uninit(struct nvme_ctrl *ctrl);
 void nvme_mpath_stop(struct nvme_ctrl *ctrl);
-void nvme_mpath_clear_current_path(struct nvme_ns *ns);
+bool nvme_mpath_clear_current_path(struct nvme_ns *ns);
+void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl);
 struct nvme_ns *nvme_find_path(struct nvme_ns_head *head);
 
 static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)
@@ -548,7 +552,11 @@ static inline void nvme_mpath_add_disk(struct nvme_ns *ns,
 static inline void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 {
 }
-static inline void nvme_mpath_clear_current_path(struct nvme_ns *ns)
+static inline bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
+{
+	return false;
+}
+static inline void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 {
 }
 static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)
@@ -568,6 +576,15 @@ static inline void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
 static inline void nvme_mpath_stop(struct nvme_ctrl *ctrl)
 {
 }
+static inline void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
+{
+}
+static inline void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
+{
+}
+static inline void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
+{
+}
 #endif /* CONFIG_NVME_MULTIPATH */
 
 #ifdef CONFIG_NVM

drivers/nvme/host/pci.c

@@ -2695,7 +2695,7 @@ static void nvme_async_probe(void *data, async_cookie_t cookie)
 {
 	struct nvme_dev *dev = data;
 
-	nvme_reset_ctrl_sync(&dev->ctrl);
+	flush_work(&dev->ctrl.reset_work);
 	flush_work(&dev->ctrl.scan_work);
 	nvme_put_ctrl(&dev->ctrl);
 }
@@ -2761,6 +2761,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	dev_info(dev->ctrl.device, "pci function %s\n", dev_name(&pdev->dev));
 
+	nvme_reset_ctrl(&dev->ctrl);
 	nvme_get_ctrl(&dev->ctrl);
 	async_schedule(nvme_async_probe, dev);
 

drivers/nvme/host/rdma.c

@@ -562,13 +562,17 @@ static int nvme_rdma_alloc_queue(struct nvme_rdma_ctrl *ctrl,
 	return ret;
 }
 
+static void __nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
+{
+	rdma_disconnect(queue->cm_id);
+	ib_drain_qp(queue->qp);
+}
+
 static void nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
 {
 	if (!test_and_clear_bit(NVME_RDMA_Q_LIVE, &queue->flags))
 		return;
-
-	rdma_disconnect(queue->cm_id);
-	ib_drain_qp(queue->qp);
+	__nvme_rdma_stop_queue(queue);
 }
 
 static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
@@ -607,11 +611,13 @@ static int nvme_rdma_start_queue(struct nvme_rdma_ctrl *ctrl, int idx)
 	else
 		ret = nvmf_connect_admin_queue(&ctrl->ctrl);
 
-	if (!ret)
+	if (!ret) {
 		set_bit(NVME_RDMA_Q_LIVE, &queue->flags);
-	else
+	} else {
+		__nvme_rdma_stop_queue(queue);
 		dev_info(ctrl->ctrl.device,
 			"failed to connect queue: %d ret=%d\n", idx, ret);
+	}
 	return ret;
 }
 

drivers/nvme/target/configfs.c

@@ -675,6 +675,7 @@ static void nvmet_port_subsys_drop_link(struct config_item *parent,
 
 found:
 	list_del(&p->entry);
+	nvmet_port_del_ctrls(port, subsys);
 	nvmet_port_disc_changed(port, subsys);
 
 	if (list_empty(&port->subsystems))

drivers/nvme/target/core.c

@@ -46,6 +46,9 @@ inline u16 errno_to_nvme_status(struct nvmet_req *req, int errno)
 	u16 status;
 
 	switch (errno) {
+	case 0:
+		status = NVME_SC_SUCCESS;
+		break;
 	case -ENOSPC:
 		req->error_loc = offsetof(struct nvme_rw_command, length);
 		status = NVME_SC_CAP_EXCEEDED | NVME_SC_DNR;
@@ -280,6 +283,18 @@ void nvmet_unregister_transport(const struct nvmet_fabrics_ops *ops)
 }
 EXPORT_SYMBOL_GPL(nvmet_unregister_transport);
 
+void nvmet_port_del_ctrls(struct nvmet_port *port, struct nvmet_subsys *subsys)
+{
+	struct nvmet_ctrl *ctrl;
+
+	mutex_lock(&subsys->lock);
+	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
+		if (ctrl->port == port)
+			ctrl->ops->delete_ctrl(ctrl);
+	}
+	mutex_unlock(&subsys->lock);
+}
+
 int nvmet_enable_port(struct nvmet_port *port)
 {
 	const struct nvmet_fabrics_ops *ops;

drivers/nvme/target/loop.c

@@ -654,6 +654,14 @@ static void nvme_loop_remove_port(struct nvmet_port *port)
 	mutex_lock(&nvme_loop_ports_mutex);
 	list_del_init(&port->entry);
 	mutex_unlock(&nvme_loop_ports_mutex);
+
+	/*
+	 * Ensure any ctrls that are in the process of being
+	 * deleted are in fact deleted before we return
+	 * and free the port. This is to prevent active
+	 * ctrls from using a port after it's freed.
+	 */
+	flush_workqueue(nvme_delete_wq);
 }
 
 static const struct nvmet_fabrics_ops nvme_loop_ops = {

drivers/nvme/target/nvmet.h

@@ -418,6 +418,9 @@ void nvmet_port_send_ana_event(struct nvmet_port *port);
 int nvmet_register_transport(const struct nvmet_fabrics_ops *ops);
 void nvmet_unregister_transport(const struct nvmet_fabrics_ops *ops);
 
+void nvmet_port_del_ctrls(struct nvmet_port *port,
+			  struct nvmet_subsys *subsys);
+
 int nvmet_enable_port(struct nvmet_port *port);
 void nvmet_disable_port(struct nvmet_port *port);
 

fs/block_dev.c

@@ -345,24 +345,15 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 	struct bio *bio;
 	bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
 	bool is_read = (iov_iter_rw(iter) == READ), is_sync;
-	bool nowait = (iocb->ki_flags & IOCB_NOWAIT) != 0;
 	loff_t pos = iocb->ki_pos;
 	blk_qc_t qc = BLK_QC_T_NONE;
-	gfp_t gfp;
-	int ret;
+	int ret = 0;
 
 	if ((pos | iov_iter_alignment(iter)) &
 	    (bdev_logical_block_size(bdev) - 1))
 		return -EINVAL;
 
-	if (nowait)
-		gfp = GFP_NOWAIT;
-	else
-		gfp = GFP_KERNEL;
-
-	bio = bio_alloc_bioset(gfp, nr_pages, &blkdev_dio_pool);
-	if (!bio)
-		return -EAGAIN;
+	bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);
 
 	dio = container_of(bio, struct blkdev_dio, bio);
 	dio->is_sync = is_sync = is_sync_kiocb(iocb);
@@ -384,7 +375,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 	if (!is_poll)
 		blk_start_plug(&plug);
 
-	ret = 0;
 	for (;;) {
 		bio_set_dev(bio, bdev);
 		bio->bi_iter.bi_sector = pos >> 9;
@@ -409,14 +399,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 			task_io_account_write(bio->bi_iter.bi_size);
 		}
 
-		/*
-		 * Tell underlying layer to not block for resource shortage.
-		 * And if we would have blocked, return error inline instead
-		 * of through the bio->bi_end_io() callback.
-		 */
-		if (nowait)
-			bio->bi_opf |= (REQ_NOWAIT | REQ_NOWAIT_INLINE);
-
+		dio->size += bio->bi_iter.bi_size;
 		pos += bio->bi_iter.bi_size;
 
 		nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES);
@@ -428,13 +411,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 				polled = true;
 			}
 
-			dio->size += bio->bi_iter.bi_size;
 			qc = submit_bio(bio);
-			if (qc == BLK_QC_T_EAGAIN) {
-				dio->size -= bio->bi_iter.bi_size;
-				ret = -EAGAIN;
-				goto error;
-			}
 
 			if (polled)
 				WRITE_ONCE(iocb->ki_cookie, qc);
@@ -455,19 +432,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 			atomic_inc(&dio->ref);
 		}
 
-		dio->size += bio->bi_iter.bi_size;
-		qc = submit_bio(bio);
-		if (qc == BLK_QC_T_EAGAIN) {
-			dio->size -= bio->bi_iter.bi_size;
-			ret = -EAGAIN;
-			goto error;
-		}
-
-		bio = bio_alloc(gfp, nr_pages);
-		if (!bio) {
-			ret = -EAGAIN;
-			goto error;
-		}
+		submit_bio(bio);
+		bio = bio_alloc(GFP_KERNEL, nr_pages);
 	}
 
 	if (!is_poll)
@@ -487,7 +453,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 	}
 	__set_current_state(TASK_RUNNING);
 
-out:
 	if (!ret)
 		ret = blk_status_to_errno(dio->bio.bi_status);
 	if (likely(!ret))
@@ -495,10 +460,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 
 	bio_put(&dio->bio);
 	return ret;
-error:
-	if (!is_poll)
-		blk_finish_plug(&plug);
-	goto out;
 }
 
 static ssize_t

fs/io_uring.c

@@ -1097,10 +1097,8 @@ static int io_import_fixed(struct io_ring_ctx *ctx, int rw,
 
 			iter->bvec = bvec + seg_skip;
 			iter->nr_segs -= seg_skip;
-			iter->count -= (seg_skip << PAGE_SHIFT);
+			iter->count -= bvec->bv_len + offset;
 			iter->iov_offset = offset & ~PAGE_MASK;
-			if (iter->iov_offset)
-				iter->count -= iter->iov_offset;
 		}
 	}
 
@@ -2025,6 +2023,15 @@ static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
 {
 	int ret;
 
+	ret = io_req_defer(ctx, req, s->sqe);
+	if (ret) {
+		if (ret != -EIOCBQUEUED) {
+			io_free_req(req);
+			io_cqring_add_event(ctx, s->sqe->user_data, ret);
+		}
+		return 0;
+	}
+
 	ret = __io_submit_sqe(ctx, req, s, true);
 	if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
 		struct io_uring_sqe *sqe_copy;
@@ -2097,13 +2104,6 @@ static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
 		return;
 	}
 
-	ret = io_req_defer(ctx, req, s->sqe);
-	if (ret) {
-		if (ret != -EIOCBQUEUED)
-			goto err_req;
-		return;
-	}
-
 	/*
 	 * If we already have a head request, queue this one for async
 	 * submittal once the head completes. If we don't have a head but

include/linux/blk_types.h

@@ -311,7 +311,6 @@ enum req_flag_bits {
 	__REQ_RAHEAD,		/* read ahead, can fail anytime */
 	__REQ_BACKGROUND,	/* background IO */
 	__REQ_NOWAIT,           /* Don't wait if request will block */
-	__REQ_NOWAIT_INLINE,	/* Return would-block error inline */
 	/*
 	 * When a shared kthread needs to issue a bio for a cgroup, doing
 	 * so synchronously can lead to priority inversions as the kthread
@@ -346,7 +345,6 @@ enum req_flag_bits {
 #define REQ_RAHEAD		(1ULL << __REQ_RAHEAD)
 #define REQ_BACKGROUND		(1ULL << __REQ_BACKGROUND)
 #define REQ_NOWAIT		(1ULL << __REQ_NOWAIT)
-#define REQ_NOWAIT_INLINE	(1ULL << __REQ_NOWAIT_INLINE)
 #define REQ_CGROUP_PUNT		(1ULL << __REQ_CGROUP_PUNT)
 
 #define REQ_NOUNMAP		(1ULL << __REQ_NOUNMAP)
@@ -420,13 +418,12 @@ static inline int op_stat_group(unsigned int op)
 
 typedef unsigned int blk_qc_t;
 #define BLK_QC_T_NONE		-1U
-#define BLK_QC_T_EAGAIN		-2U
 #define BLK_QC_T_SHIFT		16
 #define BLK_QC_T_INTERNAL	(1U << 31)
 
 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 {
-	return cookie != BLK_QC_T_NONE && cookie != BLK_QC_T_EAGAIN;
+	return cookie != BLK_QC_T_NONE;
 }
 
 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)