nvme-fabrics: Add target support for FC transport

Implements the FC-NVME T11 definition of how nvme fabric capsules are
performed on an FC fabric. Utilizes a lower-layer API to FC host adapters
to send/receive FC-4 LS operations and perform the FCP transactions
necessary to perform and FCP IO request for NVME.

The T11 definitions for FC-4 Link Services are implemented which create
NVMeOF connections.  Implements the hooks with nvmet layer to pass NVME
commands to it for processing and posting of data/response base to the
host via the different connections.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Jay Freyensee <james_p_freyensee@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

3 files changed, 2301 insertions, 0 deletions

diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
index 3a5b9d0576cb..746a63e4d54a 100644
--- a/drivers/nvme/target/Kconfig
+++ b/drivers/nvme/target/Kconfig
@@ -34,3 +34,14 @@ config NVME_TARGET_RDMA
 	  devices over RDMA.
 
 	  If unsure, say N.
+
+config NVME_TARGET_FC
+	tristate "NVMe over Fabrics FC target driver"
+	depends on NVME_TARGET
+	depends on HAS_DMA
+	help
+	  This enables the NVMe FC target support, which allows exporting NVMe
+	  devices over FC.
+
+	  If unsure, say N.
+
diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
index b7a06232c9da..80b128b9ac9f 100644
--- a/drivers/nvme/target/Makefile
+++ b/drivers/nvme/target/Makefile
@@ -2,8 +2,10 @@
 obj-$(CONFIG_NVME_TARGET)		+= nvmet.o
 obj-$(CONFIG_NVME_TARGET_LOOP)		+= nvme-loop.o
 obj-$(CONFIG_NVME_TARGET_RDMA)		+= nvmet-rdma.o
+obj-$(CONFIG_NVME_TARGET_FC)		+= nvmet-fc.o
 
 nvmet-y		+= core.o configfs.o admin-cmd.o io-cmd.o fabrics-cmd.o \
 			discovery.o
 nvme-loop-y	+= loop.o
 nvmet-rdma-y	+= rdma.o
+nvmet-fc-y	+= fc.o
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
new file mode 100644
index 000000000000..173e842f19c9
--- /dev/null
+++ b/drivers/nvme/target/fc.c
@@ -0,0 +1,2288 @@
+/*
+ * Copyright (c) 2016 Avago Technologies.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful.
+ * ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
+ * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED, EXCEPT TO
+ * THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID.
+ * See the GNU General Public License for more details, a copy of which
+ * can be found in the file COPYING included with this package
+ *
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/blk-mq.h>
+#include <linux/parser.h>
+#include <linux/random.h>
+#include <uapi/scsi/fc/fc_fs.h>
+#include <uapi/scsi/fc/fc_els.h>
+
+#include "nvmet.h"
+#include <linux/nvme-fc-driver.h>
+#include <linux/nvme-fc.h>
+
+
+/* *************************** Data Structures/Defines ****************** */
+
+
+#define NVMET_LS_CTX_COUNT		4
+
+/* for this implementation, assume small single frame rqst/rsp */
+#define NVME_FC_MAX_LS_BUFFER_SIZE		2048
+
+struct nvmet_fc_tgtport;
+struct nvmet_fc_tgt_assoc;
+
+struct nvmet_fc_ls_iod {
+	struct nvmefc_tgt_ls_req	*lsreq;
+	struct nvmefc_tgt_fcp_req	*fcpreq;	/* only if RS */
+
+	struct list_head		ls_list;	/* tgtport->ls_list */
+
+	struct nvmet_fc_tgtport		*tgtport;
+	struct nvmet_fc_tgt_assoc	*assoc;
+
+	u8				*rqstbuf;
+	u8				*rspbuf;
+	u16				rqstdatalen;
+	dma_addr_t			rspdma;
+
+	struct scatterlist		sg[2];
+
+	struct work_struct		work;
+} __aligned(sizeof(unsigned long long));
+
+#define NVMET_FC_MAX_KB_PER_XFR		256
+
+enum nvmet_fcp_datadir {
+	NVMET_FCP_NODATA,
+	NVMET_FCP_WRITE,
+	NVMET_FCP_READ,
+	NVMET_FCP_ABORTED,
+};
+
+struct nvmet_fc_fcp_iod {
+	struct nvmefc_tgt_fcp_req	*fcpreq;
+
+	struct nvme_fc_cmd_iu		cmdiubuf;
+	struct nvme_fc_ersp_iu		rspiubuf;
+	dma_addr_t			rspdma;
+	struct scatterlist		*data_sg;
+	struct scatterlist		*next_sg;
+	int				data_sg_cnt;
+	u32				next_sg_offset;
+	u32				total_length;
+	u32				offset;
+	enum nvmet_fcp_datadir		io_dir;
+	bool				active;
+	bool				abort;
+	spinlock_t			flock;
+
+	struct nvmet_req		req;
+	struct work_struct		work;
+
+	struct nvmet_fc_tgtport		*tgtport;
+	struct nvmet_fc_tgt_queue	*queue;
+
+	struct list_head		fcp_list;	/* tgtport->fcp_list */
+};
+
+struct nvmet_fc_tgtport {
+
+	struct nvmet_fc_target_port	fc_target_port;
+
+	struct list_head		tgt_list; /* nvmet_fc_target_list */
+	struct device			*dev;	/* dev for dma mapping */
+	struct nvmet_fc_target_template	*ops;
+
+	struct nvmet_fc_ls_iod		*iod;
+	spinlock_t			lock;
+	struct list_head		ls_list;
+	struct list_head		ls_busylist;
+	struct list_head		assoc_list;
+	struct ida			assoc_cnt;
+	struct nvmet_port		*port;
+	struct kref			ref;
+};
+
+struct nvmet_fc_tgt_queue {
+	bool				ninetypercent;
+	u16				qid;
+	u16				sqsize;
+	u16				ersp_ratio;
+	u16				sqhd;
+	int				cpu;
+	atomic_t			connected;
+	atomic_t			sqtail;
+	atomic_t			zrspcnt;
+	atomic_t			rsn;
+	spinlock_t			qlock;
+	struct nvmet_port		*port;
+	struct nvmet_cq			nvme_cq;
+	struct nvmet_sq			nvme_sq;
+	struct nvmet_fc_tgt_assoc	*assoc;
+	struct nvmet_fc_fcp_iod		*fod;		/* array of fcp_iods */
+	struct list_head		fod_list;
+	struct workqueue_struct		*work_q;
+	struct kref			ref;
+} __aligned(sizeof(unsigned long long));
+
+struct nvmet_fc_tgt_assoc {
+	u64				association_id;
+	u32				a_id;
+	struct nvmet_fc_tgtport		*tgtport;
+	struct list_head		a_list;
+	struct nvmet_fc_tgt_queue	*queues[NVMET_NR_QUEUES];
+	struct kref			ref;
+};
+
+
+static inline int
+nvmet_fc_iodnum(struct nvmet_fc_ls_iod *iodptr)
+{
+	return (iodptr - iodptr->tgtport->iod);
+}
+
+static inline int
+nvmet_fc_fodnum(struct nvmet_fc_fcp_iod *fodptr)
+{
+	return (fodptr - fodptr->queue->fod);
+}
+
+
+/*
+ * Association and Connection IDs:
+ *
+ * Association ID will have random number in upper 6 bytes and zero
+ *   in lower 2 bytes
+ *
+ * Connection IDs will be Association ID with QID or'd in lower 2 bytes
+ *
+ * note: Association ID = Connection ID for queue 0
+ */
+#define BYTES_FOR_QID			sizeof(u16)
+#define BYTES_FOR_QID_SHIFT		(BYTES_FOR_QID * 8)
+#define NVMET_FC_QUEUEID_MASK		((u64)((1 << BYTES_FOR_QID_SHIFT) - 1))
+
+static inline u64
+nvmet_fc_makeconnid(struct nvmet_fc_tgt_assoc *assoc, u16 qid)
+{
+	return (assoc->association_id | qid);
+}
+
+static inline u64
+nvmet_fc_getassociationid(u64 connectionid)
+{
+	return connectionid & ~NVMET_FC_QUEUEID_MASK;
+}
+
+static inline u16
+nvmet_fc_getqueueid(u64 connectionid)
+{
+	return (u16)(connectionid & NVMET_FC_QUEUEID_MASK);
+}
+
+static inline struct nvmet_fc_tgtport *
+targetport_to_tgtport(struct nvmet_fc_target_port *targetport)
+{
+	return container_of(targetport, struct nvmet_fc_tgtport,
+				 fc_target_port);
+}
+
+static inline struct nvmet_fc_fcp_iod *
+nvmet_req_to_fod(struct nvmet_req *nvme_req)
+{
+	return container_of(nvme_req, struct nvmet_fc_fcp_iod, req);
+}
+
+
+/* *************************** Globals **************************** */
+
+
+static DEFINE_SPINLOCK(nvmet_fc_tgtlock);
+
+static LIST_HEAD(nvmet_fc_target_list);
+static DEFINE_IDA(nvmet_fc_tgtport_cnt);
+
+
+static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
+static void nvmet_fc_handle_fcp_rqst_work(struct work_struct *work);
+static void nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc);
+static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
+static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
+static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
+static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
+static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);
+
+
+/* *********************** FC-NVME DMA Handling **************************** */
+
+/*
+ * The fcloop device passes in a NULL device pointer. Real LLD's will
+ * pass in a valid device pointer. If NULL is passed to the dma mapping
+ * routines, depending on the platform, it may or may not succeed, and
+ * may crash.
+ *
+ * As such:
+ * Wrapper all the dma routines and check the dev pointer.
+ *
+ * If simple mappings (return just a dma address, we'll noop them,
+ * returning a dma address of 0.
+ *
+ * On more complex mappings (dma_map_sg), a pseudo routine fills
+ * in the scatter list, setting all dma addresses to 0.
+ */
+
+static inline dma_addr_t
+fc_dma_map_single(struct device *dev, void *ptr, size_t size,
+		enum dma_data_direction dir)
+{
+	return dev ? dma_map_single(dev, ptr, size, dir) : (dma_addr_t)0L;
+}
+
+static inline int
+fc_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return dev ? dma_mapping_error(dev, dma_addr) : 0;
+}
+
+static inline void
+fc_dma_unmap_single(struct device *dev, dma_addr_t addr, size_t size,
+	enum dma_data_direction dir)
+{
+	if (dev)
+		dma_unmap_single(dev, addr, size, dir);
+}
+
+static inline void
+fc_dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir)
+{
+	if (dev)
+		dma_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static inline void
+fc_dma_sync_single_for_device(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir)
+{
+	if (dev)
+		dma_sync_single_for_device(dev, addr, size, dir);
+}
+
+/* pseudo dma_map_sg call */
+static int
+fc_map_sg(struct scatterlist *sg, int nents)
+{
+	struct scatterlist *s;
+	int i;
+
+	WARN_ON(nents == 0 || sg[0].length == 0);
+
+	for_each_sg(sg, s, nents, i) {
+		s->dma_address = 0L;
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+		s->dma_length = s->length;
+#endif
+	}
+	return nents;
+}
+
+static inline int
+fc_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir)
+{
+	return dev ? dma_map_sg(dev, sg, nents, dir) : fc_map_sg(sg, nents);
+}
+
+static inline void
+fc_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir)
+{
+	if (dev)
+		dma_unmap_sg(dev, sg, nents, dir);
+}
+
+
+/* *********************** FC-NVME Port Management ************************ */
+
+
+static int
+nvmet_fc_alloc_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_ls_iod *iod;
+	int i;
+
+	iod = kcalloc(NVMET_LS_CTX_COUNT, sizeof(struct nvmet_fc_ls_iod),
+			GFP_KERNEL);
+	if (!iod)
+		return -ENOMEM;
+
+	tgtport->iod = iod;
+
+	for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
+		INIT_WORK(&iod->work, nvmet_fc_handle_ls_rqst_work);
+		iod->tgtport = tgtport;
+		list_add_tail(&iod->ls_list, &tgtport->ls_list);
+
+		iod->rqstbuf = kcalloc(2, NVME_FC_MAX_LS_BUFFER_SIZE,
+			GFP_KERNEL);
+		if (!iod->rqstbuf)
+			goto out_fail;
+
+		iod->rspbuf = iod->rqstbuf + NVME_FC_MAX_LS_BUFFER_SIZE;
+
+		iod->rspdma = fc_dma_map_single(tgtport->dev, iod->rspbuf,
+						NVME_FC_MAX_LS_BUFFER_SIZE,
+						DMA_TO_DEVICE);
+		if (fc_dma_mapping_error(tgtport->dev, iod->rspdma))
+			goto out_fail;
+	}
+
+	return 0;
+
+out_fail:
+	kfree(iod->rqstbuf);
+	list_del(&iod->ls_list);
+	for (iod--, i--; i >= 0; iod--, i--) {
+		fc_dma_unmap_single(tgtport->dev, iod->rspdma,
+				NVME_FC_MAX_LS_BUFFER_SIZE, DMA_TO_DEVICE);
+		kfree(iod->rqstbuf);
+		list_del(&iod->ls_list);
+	}
+
+	kfree(iod);
+
+	return -EFAULT;
+}
+
+static void
+nvmet_fc_free_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_ls_iod *iod = tgtport->iod;
+	int i;
+
+	for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
+		fc_dma_unmap_single(tgtport->dev,
+				iod->rspdma, NVME_FC_MAX_LS_BUFFER_SIZE,
+				DMA_TO_DEVICE);
+		kfree(iod->rqstbuf);
+		list_del(&iod->ls_list);
+	}
+	kfree(tgtport->iod);
+}
+
+static struct nvmet_fc_ls_iod *
+nvmet_fc_alloc_ls_iod(struct nvmet_fc_tgtport *tgtport)
+{
+	static struct nvmet_fc_ls_iod *iod;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	iod = list_first_entry_or_null(&tgtport->ls_list,
+					struct nvmet_fc_ls_iod, ls_list);
+	if (iod)
+		list_move_tail(&iod->ls_list, &tgtport->ls_busylist);
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+	return iod;
+}
+
+
+static void
+nvmet_fc_free_ls_iod(struct nvmet_fc_tgtport *tgtport,
+			struct nvmet_fc_ls_iod *iod)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	list_move(&iod->ls_list, &tgtport->ls_list);
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+}
+
+static void
+nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
+				struct nvmet_fc_tgt_queue *queue)
+{
+	struct nvmet_fc_fcp_iod *fod = queue->fod;
+	int i;
+
+	for (i = 0; i < queue->sqsize; fod++, i++) {
+		INIT_WORK(&fod->work, nvmet_fc_handle_fcp_rqst_work);
+		fod->tgtport = tgtport;
+		fod->queue = queue;
+		fod->active = false;
+		list_add_tail(&fod->fcp_list, &queue->fod_list);
+		spin_lock_init(&fod->flock);
+
+		fod->rspdma = fc_dma_map_single(tgtport->dev, &fod->rspiubuf,
+					sizeof(fod->rspiubuf), DMA_TO_DEVICE);
+		if (fc_dma_mapping_error(tgtport->dev, fod->rspdma)) {
+			list_del(&fod->fcp_list);
+			for (fod--, i--; i >= 0; fod--, i--) {
+				fc_dma_unmap_single(tgtport->dev, fod->rspdma,
+						sizeof(fod->rspiubuf),
+						DMA_TO_DEVICE);
+				fod->rspdma = 0L;
+				list_del(&fod->fcp_list);
+			}
+
+			return;
+		}
+	}
+}
+
+static void
+nvmet_fc_destroy_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
+				struct nvmet_fc_tgt_queue *queue)
+{
+	struct nvmet_fc_fcp_iod *fod = queue->fod;
+	int i;
+
+	for (i = 0; i < queue->sqsize; fod++, i++) {
+		if (fod->rspdma)
+			fc_dma_unmap_single(tgtport->dev, fod->rspdma,
+				sizeof(fod->rspiubuf), DMA_TO_DEVICE);
+	}
+}
+
+static struct nvmet_fc_fcp_iod *
+nvmet_fc_alloc_fcp_iod(struct nvmet_fc_tgt_queue *queue)
+{
+	static struct nvmet_fc_fcp_iod *fod;
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->qlock, flags);
+	fod = list_first_entry_or_null(&queue->fod_list,
+					struct nvmet_fc_fcp_iod, fcp_list);
+	if (fod) {
+		list_del(&fod->fcp_list);
+		fod->active = true;
+		fod->abort = false;
+		/*
+		 * no queue reference is taken, as it was taken by the
+		 * queue lookup just prior to the allocation. The iod
+		 * will "inherit" that reference.
+		 */
+	}
+	spin_unlock_irqrestore(&queue->qlock, flags);
+	return fod;
+}
+
+
+static void
+nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
+			struct nvmet_fc_fcp_iod *fod)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->qlock, flags);
+	list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
+	fod->active = false;
+	spin_unlock_irqrestore(&queue->qlock, flags);
+
+	/*
+	 * release the reference taken at queue lookup and fod allocation
+	 */
+	nvmet_fc_tgt_q_put(queue);
+}
+
+static int
+nvmet_fc_queue_to_cpu(struct nvmet_fc_tgtport *tgtport, int qid)
+{
+	int cpu, idx, cnt;
+
+	if (!(tgtport->ops->target_features &
+			NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED) ||
+	    tgtport->ops->max_hw_queues == 1)
+		return WORK_CPU_UNBOUND;
+
+	/* Simple cpu selection based on qid modulo active cpu count */
+	idx = !qid ? 0 : (qid - 1) % num_active_cpus();
+
+	/* find the n'th active cpu */
+	for (cpu = 0, cnt = 0; ; ) {
+		if (cpu_active(cpu)) {
+			if (cnt == idx)
+				break;
+			cnt++;
+		}
+		cpu = (cpu + 1) % num_possible_cpus();
+	}
+
+	return cpu;
+}
+
+static struct nvmet_fc_tgt_queue *
+nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
+			u16 qid, u16 sqsize)
+{
+	struct nvmet_fc_tgt_queue *queue;
+	unsigned long flags;
+	int ret;
+
+	if (qid >= NVMET_NR_QUEUES)
+		return NULL;
+
+	queue = kzalloc((sizeof(*queue) +
+				(sizeof(struct nvmet_fc_fcp_iod) * sqsize)),
+				GFP_KERNEL);
+	if (!queue)
+		return NULL;
+
+	if (!nvmet_fc_tgt_a_get(assoc))
+		goto out_free_queue;
+
+	queue->work_q = alloc_workqueue("ntfc%d.%d.%d", 0, 0,
+				assoc->tgtport->fc_target_port.port_num,
+				assoc->a_id, qid);
+	if (!queue->work_q)
+		goto out_a_put;
+
+	queue->fod = (struct nvmet_fc_fcp_iod *)&queue[1];
+	queue->qid = qid;
+	queue->sqsize = sqsize;
+	queue->assoc = assoc;
+	queue->port = assoc->tgtport->port;
+	queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
+	INIT_LIST_HEAD(&queue->fod_list);
+	atomic_set(&queue->connected, 0);
+	atomic_set(&queue->sqtail, 0);
+	atomic_set(&queue->rsn, 1);
+	atomic_set(&queue->zrspcnt, 0);
+	spin_lock_init(&queue->qlock);
+	kref_init(&queue->ref);
+
+	nvmet_fc_prep_fcp_iodlist(assoc->tgtport, queue);
+
+	ret = nvmet_sq_init(&queue->nvme_sq);
+	if (ret)
+		goto out_fail_iodlist;
+
+	WARN_ON(assoc->queues[qid]);
+	spin_lock_irqsave(&assoc->tgtport->lock, flags);
+	assoc->queues[qid] = queue;
+	spin_unlock_irqrestore(&assoc->tgtport->lock, flags);
+
+	return queue;
+
+out_fail_iodlist:
+	nvmet_fc_destroy_fcp_iodlist(assoc->tgtport, queue);
+	destroy_workqueue(queue->work_q);
+out_a_put:
+	nvmet_fc_tgt_a_put(assoc);
+out_free_queue:
+	kfree(queue);
+	return NULL;
+}
+
+
+static void
+nvmet_fc_tgt_queue_free(struct kref *ref)
+{
+	struct nvmet_fc_tgt_queue *queue =
+		container_of(ref, struct nvmet_fc_tgt_queue, ref);
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->assoc->tgtport->lock, flags);
+	queue->assoc->queues[queue->qid] = NULL;
+	spin_unlock_irqrestore(&queue->assoc->tgtport->lock, flags);
+
+	nvmet_fc_destroy_fcp_iodlist(queue->assoc->tgtport, queue);
+
+	nvmet_fc_tgt_a_put(queue->assoc);
+
+	destroy_workqueue(queue->work_q);
+
+	kfree(queue);
+}
+
+static void
+nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue)
+{
+	kref_put(&queue->ref, nvmet_fc_tgt_queue_free);
+}
+
+static int
+nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue)
+{
+	return kref_get_unless_zero(&queue->ref);
+}
+
+
+static void
+nvmet_fc_abort_op(struct nvmet_fc_tgtport *tgtport,
+				struct nvmefc_tgt_fcp_req *fcpreq)
+{
+	int ret;
+
+	fcpreq->op = NVMET_FCOP_ABORT;
+	fcpreq->offset = 0;
+	fcpreq->timeout = 0;
+	fcpreq->transfer_length = 0;
+	fcpreq->transferred_length = 0;
+	fcpreq->fcp_error = 0;
+	fcpreq->sg_cnt = 0;
+
+	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fcpreq);
+	if (ret)
+		/* should never reach here !! */
+		WARN_ON(1);
+}
+
+
+static void
+nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
+{
+	struct nvmet_fc_fcp_iod *fod = queue->fod;
+	unsigned long flags;
+	int i;
+	bool disconnect;
+
+	disconnect = atomic_xchg(&queue->connected, 0);
+
+	spin_lock_irqsave(&queue->qlock, flags);
+	/* about outstanding io's */
+	for (i = 0; i < queue->sqsize; fod++, i++) {
+		if (fod->active) {
+			spin_lock(&fod->flock);
+			fod->abort = true;
+			spin_unlock(&fod->flock);
+		}
+	}
+	spin_unlock_irqrestore(&queue->qlock, flags);
+
+	flush_workqueue(queue->work_q);
+
+	if (disconnect)
+		nvmet_sq_destroy(&queue->nvme_sq);
+
+	nvmet_fc_tgt_q_put(queue);
+}
+
+static struct nvmet_fc_tgt_queue *
+nvmet_fc_find_target_queue(struct nvmet_fc_tgtport *tgtport,
+				u64 connection_id)
+{
+	struct nvmet_fc_tgt_assoc *assoc;
+	struct nvmet_fc_tgt_queue *queue;
+	u64 association_id = nvmet_fc_getassociationid(connection_id);
+	u16 qid = nvmet_fc_getqueueid(connection_id);
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
+		if (association_id == assoc->association_id) {
+			queue = assoc->queues[qid];
+			if (queue &&
+			    (!atomic_read(&queue->connected) ||
+			     !nvmet_fc_tgt_q_get(queue)))
+				queue = NULL;
+			spin_unlock_irqrestore(&tgtport->lock, flags);
+			return queue;
+		}
+	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+	return NULL;
+}
+
+static struct nvmet_fc_tgt_assoc *
+nvmet_fc_alloc_target_assoc(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_tgt_assoc *assoc, *tmpassoc;
+	unsigned long flags;
+	u64 ran;
+	int idx;
+	bool needrandom = true;
+
+	assoc = kzalloc(sizeof(*assoc), GFP_KERNEL);
+	if (!assoc)
+		return NULL;
+
+	idx = ida_simple_get(&tgtport->assoc_cnt, 0, 0, GFP_KERNEL);
+	if (idx < 0)
+		goto out_free_assoc;
+
+	if (!nvmet_fc_tgtport_get(tgtport))
+		goto out_ida_put;
+
+	assoc->tgtport = tgtport;
+	assoc->a_id = idx;
+	INIT_LIST_HEAD(&assoc->a_list);
+	kref_init(&assoc->ref);
+
+	while (needrandom) {
+		get_random_bytes(&ran, sizeof(ran) - BYTES_FOR_QID);
+		ran = ran << BYTES_FOR_QID_SHIFT;
+
+		spin_lock_irqsave(&tgtport->lock, flags);
+		needrandom = false;
+		list_for_each_entry(tmpassoc, &tgtport->assoc_list, a_list)
+			if (ran == tmpassoc->association_id) {
+				needrandom = true;
+				break;
+			}
+		if (!needrandom) {
+			assoc->association_id = ran;
+			list_add_tail(&assoc->a_list, &tgtport->assoc_list);
+		}
+		spin_unlock_irqrestore(&tgtport->lock, flags);
+	}
+
+	return assoc;
+
+out_ida_put:
+	ida_simple_remove(&tgtport->assoc_cnt, idx);
+out_free_assoc:
+	kfree(assoc);
+	return NULL;
+}
+
+static void
+nvmet_fc_target_assoc_free(struct kref *ref)
+{
+	struct nvmet_fc_tgt_assoc *assoc =
+		container_of(ref, struct nvmet_fc_tgt_assoc, ref);
+	struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	list_del(&assoc->a_list);
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+	ida_simple_remove(&tgtport->assoc_cnt, assoc->a_id);
+	kfree(assoc);
+	nvmet_fc_tgtport_put(tgtport);
+}
+
+static void
+nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc)
+{
+	kref_put(&assoc->ref, nvmet_fc_target_assoc_free);
+}
+
+static int
+nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc)
+{
+	return kref_get_unless_zero(&assoc->ref);
+}
+
+static void
+nvmet_fc_delete_target_assoc(struct nvmet_fc_tgt_assoc *assoc)
+{
+	struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
+	struct nvmet_fc_tgt_queue *queue;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	for (i = NVMET_NR_QUEUES - 1; i >= 0; i--) {
+		queue = assoc->queues[i];
+		if (queue) {
+			if (!nvmet_fc_tgt_q_get(queue))
+				continue;
+			spin_unlock_irqrestore(&tgtport->lock, flags);
+			nvmet_fc_delete_target_queue(queue);
+			nvmet_fc_tgt_q_put(queue);
+			spin_lock_irqsave(&tgtport->lock, flags);
+		}
+	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+
+	nvmet_fc_tgt_a_put(assoc);
+}
+
+static struct nvmet_fc_tgt_assoc *
+nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
+				u64 association_id)
+{
+	struct nvmet_fc_tgt_assoc *assoc;
+	struct nvmet_fc_tgt_assoc *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
+		if (association_id == assoc->association_id) {
+			ret = assoc;
+			nvmet_fc_tgt_a_get(assoc);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+
+	return ret;
+}
+
+
+/**
+ * nvme_fc_register_targetport - transport entry point called by an
+ *                              LLDD to register the existence of a local
+ *                              NVME subystem FC port.
+ * @pinfo:     pointer to information about the port to be registered
+ * @template:  LLDD entrypoints and operational parameters for the port
+ * @dev:       physical hardware device node port corresponds to. Will be
+ *             used for DMA mappings
+ * @portptr:   pointer to a local port pointer. Upon success, the routine
+ *             will allocate a nvme_fc_local_port structure and place its
+ *             address in the local port pointer. Upon failure, local port
+ *             pointer will be set to NULL.
+ *
+ * Returns:
+ * a completion status. Must be 0 upon success; a negative errno
+ * (ex: -ENXIO) upon failure.
+ */
+int
+nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
+			struct nvmet_fc_target_template *template,
+			struct device *dev,
+			struct nvmet_fc_target_port **portptr)
+{
+	struct nvmet_fc_tgtport *newrec;
+	unsigned long flags;
+	int ret, idx;
+
+	if (!template->xmt_ls_rsp || !template->fcp_op ||
+	    !template->targetport_delete ||
+	    !template->max_hw_queues || !template->max_sgl_segments ||
+	    !template->max_dif_sgl_segments || !template->dma_boundary) {
+		ret = -EINVAL;
+		goto out_regtgt_failed;
+	}
+
+	newrec = kzalloc((sizeof(*newrec) + template->target_priv_sz),
+			 GFP_KERNEL);
+	if (!newrec) {
+		ret = -ENOMEM;
+		goto out_regtgt_failed;
+	}
+
+	idx = ida_simple_get(&nvmet_fc_tgtport_cnt, 0, 0, GFP_KERNEL);
+	if (idx < 0) {
+		ret = -ENOSPC;
+		goto out_fail_kfree;
+	}
+
+	if (!get_device(dev) && dev) {
+		ret = -ENODEV;
+		goto out_ida_put;
+	}
+
+	newrec->fc_target_port.node_name = pinfo->node_name;
+	newrec->fc_target_port.port_name = pinfo->port_name;
+	newrec->fc_target_port.private = &newrec[1];
+	newrec->fc_target_port.port_id = pinfo->port_id;
+	newrec->fc_target_port.port_num = idx;
+	INIT_LIST_HEAD(&newrec->tgt_list);
+	newrec->dev = dev;
+	newrec->ops = template;
+	spin_lock_init(&newrec->lock);
+	INIT_LIST_HEAD(&newrec->ls_list);
+	INIT_LIST_HEAD(&newrec->ls_busylist);
+	INIT_LIST_HEAD(&newrec->assoc_list);
+	kref_init(&newrec->ref);
+	ida_init(&newrec->assoc_cnt);
+
+	ret = nvmet_fc_alloc_ls_iodlist(newrec);
+	if (ret) {
+		ret = -ENOMEM;
+		goto out_free_newrec;
+	}
+
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+
+	*portptr = &newrec->fc_target_port;
+	return 0;
+
+out_free_newrec:
+	put_device(dev);
+out_ida_put:
+	ida_simple_remove(&nvmet_fc_tgtport_cnt, idx);
+out_fail_kfree:
+	kfree(newrec);
+out_regtgt_failed:
+	*portptr = NULL;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nvmet_fc_register_targetport);
+
+
+static void
+nvmet_fc_free_tgtport(struct kref *ref)
+{
+	struct nvmet_fc_tgtport *tgtport =
+		container_of(ref, struct nvmet_fc_tgtport, ref);
+	struct device *dev = tgtport->dev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_del(&tgtport->tgt_list);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+
+	nvmet_fc_free_ls_iodlist(tgtport);
+
+	/* let the LLDD know we've finished tearing it down */
+	tgtport->ops->targetport_delete(&tgtport->fc_target_port);
+
+	ida_simple_remove(&nvmet_fc_tgtport_cnt,
+			tgtport->fc_target_port.port_num);
+
+	ida_destroy(&tgtport->assoc_cnt);
+
+	kfree(tgtport);
+
+	put_device(dev);
+}
+
+static void
+nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport)
+{
+	kref_put(&tgtport->ref, nvmet_fc_free_tgtport);
+}
+
+static int
+nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport)
+{
+	return kref_get_unless_zero(&tgtport->ref);
+}
+
+static void
+__nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
+{
+	struct nvmet_fc_tgt_assoc *assoc, *next;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tgtport->lock, flags);
+	list_for_each_entry_safe(assoc, next,
+				&tgtport->assoc_list, a_list) {
+		if (!nvmet_fc_tgt_a_get(assoc))
+			continue;
+		spin_unlock_irqrestore(&tgtport->lock, flags);
+		nvmet_fc_delete_target_assoc(assoc);
+		nvmet_fc_tgt_a_put(assoc);
+		spin_lock_irqsave(&tgtport->lock, flags);
+	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+}
+
+/*
+ * nvmet layer has called to terminate an association
+ */
+static void
+nvmet_fc_delete_ctrl(struct nvmet_ctrl *ctrl)
+{
+	struct nvmet_fc_tgtport *tgtport, *next;
+	struct nvmet_fc_tgt_assoc *assoc;
+	struct nvmet_fc_tgt_queue *queue;
+	unsigned long flags;
+	bool found_ctrl = false;
+
+	/* this is a bit ugly, but don't want to make locks layered */
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry_safe(tgtport, next, &nvmet_fc_target_list,
+			tgt_list) {
+		if (!nvmet_fc_tgtport_get(tgtport))
+			continue;
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+
+		spin_lock_irqsave(&tgtport->lock, flags);
+		list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
+			queue = assoc->queues[0];
+			if (queue && queue->nvme_sq.ctrl == ctrl) {
+				if (nvmet_fc_tgt_a_get(assoc))
+					found_ctrl = true;
+				break;
+			}
+		}
+		spin_unlock_irqrestore(&tgtport->lock, flags);
+
+		nvmet_fc_tgtport_put(tgtport);
+
+		if (found_ctrl) {
+			nvmet_fc_delete_target_assoc(assoc);
+			nvmet_fc_tgt_a_put(assoc);
+			return;
+		}
+
+		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+}
+
+/**
+ * nvme_fc_unregister_targetport - transport entry point called by an
+ *                              LLDD to deregister/remove a previously
+ *                              registered a local NVME subsystem FC port.
+ * @tgtport: pointer to the (registered) target port that is to be
+ *           deregistered.
+ *
+ * Returns:
+ * a completion status. Must be 0 upon success; a negative errno
+ * (ex: -ENXIO) upon failure.
+ */
+int
+nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
+{
+	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
+
+	/* terminate any outstanding associations */
+	__nvmet_fc_free_assocs(tgtport);
+
+	nvmet_fc_tgtport_put(tgtport);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvmet_fc_unregister_targetport);
+
+
+/* *********************** FC-NVME LS Handling **************************** */
+
+
+static void
+nvmet_fc_format_rsp_hdr(void *buf, u8 ls_cmd, u32 desc_len, u8 rqst_ls_cmd)
+{
+	struct fcnvme_ls_acc_hdr *acc = buf;
+
+	acc->w0.ls_cmd = ls_cmd;
+	acc->desc_list_len = desc_len;
+	acc->rqst.desc_tag = cpu_to_be32(FCNVME_LSDESC_RQST);
+	acc->rqst.desc_len =
+			fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rqst));
+	acc->rqst.w0.ls_cmd = rqst_ls_cmd;
+}
+
+static int
+nvmet_fc_format_rjt(void *buf, u16 buflen, u8 ls_cmd,
+			u8 reason, u8 explanation, u8 vendor)
+{
+	struct fcnvme_ls_rjt *rjt = buf;
+
+	nvmet_fc_format_rsp_hdr(buf, FCNVME_LSDESC_RQST,
+			fcnvme_lsdesc_len(sizeof(struct fcnvme_ls_rjt)),
+			ls_cmd);
+	rjt->rjt.desc_tag = cpu_to_be32(FCNVME_LSDESC_RJT);
+	rjt->rjt.desc_len = fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rjt));
+	rjt->rjt.reason_code = reason;
+	rjt->rjt.reason_explanation = explanation;
+	rjt->rjt.vendor = vendor;
+
+	return sizeof(struct fcnvme_ls_rjt);
+}
+
+/* Validation Error indexes into the string table below */
+enum {
+	VERR_NO_ERROR		= 0,
+	VERR_CR_ASSOC_LEN	= 1,
+	VERR_CR_ASSOC_RQST_LEN	= 2,
+	VERR_CR_ASSOC_CMD	= 3,
+	VERR_CR_ASSOC_CMD_LEN	= 4,
+	VERR_ERSP_RATIO		= 5,
+	VERR_ASSOC_ALLOC_FAIL	= 6,
+	VERR_QUEUE_ALLOC_FAIL	= 7,
+	VERR_CR_CONN_LEN	= 8,
+	VERR_CR_CONN_RQST_LEN	= 9,
+	VERR_ASSOC_ID		= 10,
+	VERR_ASSOC_ID_LEN	= 11,
+	VERR_NO_ASSOC		= 12,
+	VERR_CONN_ID		= 13,
+	VERR_CONN_ID_LEN	= 14,
+	VERR_NO_CONN		= 15,
+	VERR_CR_CONN_CMD	= 16,
+	VERR_CR_CONN_CMD_LEN	= 17,
+	VERR_DISCONN_LEN	= 18,
+	VERR_DISCONN_RQST_LEN	= 19,
+	VERR_DISCONN_CMD	= 20,
+	VERR_DISCONN_CMD_LEN	= 21,
+	VERR_DISCONN_SCOPE	= 22,
+	VERR_RS_LEN		= 23,
+	VERR_RS_RQST_LEN	= 24,
+	VERR_RS_CMD		= 25,
+	VERR_RS_CMD_LEN		= 26,
+	VERR_RS_RCTL		= 27,
+	VERR_RS_RO		= 28,
+};
+
+static char *validation_errors[] = {
+	"OK",
+	"Bad CR_ASSOC Length",
+	"Bad CR_ASSOC Rqst Length",
+	"Not CR_ASSOC Cmd",
+	"Bad CR_ASSOC Cmd Length",
+	"Bad Ersp Ratio",
+	"Association Allocation Failed",
+	"Queue Allocation Failed",
+	"Bad CR_CONN Length",
+	"Bad CR_CONN Rqst Length",
+	"Not Association ID",
+	"Bad Association ID Length",
+	"No Association",
+	"Not Connection ID",
+	"Bad Connection ID Length",