Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3543 insertions, 0 deletions

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
new file mode 100644
index 0000000000..f8e92404a6
--- /dev/null
+++ b/drivers/nvme/host/pci.c
@@ -0,0 +1,3543 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVM Express device driver
+ * Copyright (c) 2011-2014, Intel Corporation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/async.h>
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/blk-mq-pci.h>
+#include <linux/blk-integrity.h>
+#include <linux/dmi.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kstrtox.h>
+#include <linux/memremap.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/once.h>
+#include <linux/pci.h>
+#include <linux/suspend.h>
+#include <linux/t10-pi.h>
+#include <linux/types.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
+#include <linux/sed-opal.h>
+#include <linux/pci-p2pdma.h>
+
+#include "trace.h"
+#include "nvme.h"
+
+#define SQ_SIZE(q)	((q)->q_depth << (q)->sqes)
+#define CQ_SIZE(q)	((q)->q_depth * sizeof(struct nvme_completion))
+
+#define SGES_PER_PAGE	(NVME_CTRL_PAGE_SIZE / sizeof(struct nvme_sgl_desc))
+
+/*
+ * These can be higher, but we need to ensure that any command doesn't
+ * require an sg allocation that needs more than a page of data.
+ */
+#define NVME_MAX_KB_SZ	8192
+#define NVME_MAX_SEGS	128
+#define NVME_MAX_NR_ALLOCATIONS	5
+
+static int use_threaded_interrupts;
+module_param(use_threaded_interrupts, int, 0444);
+
+static bool use_cmb_sqes = true;
+module_param(use_cmb_sqes, bool, 0444);
+MODULE_PARM_DESC(use_cmb_sqes, "use controller's memory buffer for I/O SQes");
+
+static unsigned int max_host_mem_size_mb = 128;
+module_param(max_host_mem_size_mb, uint, 0444);
+MODULE_PARM_DESC(max_host_mem_size_mb,
+	"Maximum Host Memory Buffer (HMB) size per controller (in MiB)");
+
+static unsigned int sgl_threshold = SZ_32K;
+module_param(sgl_threshold, uint, 0644);
+MODULE_PARM_DESC(sgl_threshold,
+		"Use SGLs when average request segment size is larger or equal to "
+		"this size. Use 0 to disable SGLs.");
+
+#define NVME_PCI_MIN_QUEUE_SIZE 2
+#define NVME_PCI_MAX_QUEUE_SIZE 4095
+static int io_queue_depth_set(const char *val, const struct kernel_param *kp);
+static const struct kernel_param_ops io_queue_depth_ops = {
+	.set = io_queue_depth_set,
+	.get = param_get_uint,
+};
+
+static unsigned int io_queue_depth = 1024;
+module_param_cb(io_queue_depth, &io_queue_depth_ops, &io_queue_depth, 0644);
+MODULE_PARM_DESC(io_queue_depth, "set io queue depth, should >= 2 and < 4096");
+
+static int io_queue_count_set(const char *val, const struct kernel_param *kp)
+{
+	unsigned int n;
+	int ret;
+
+	ret = kstrtouint(val, 10, &n);
+	if (ret != 0 || n > num_possible_cpus())
+		return -EINVAL;
+	return param_set_uint(val, kp);
+}
+
+static const struct kernel_param_ops io_queue_count_ops = {
+	.set = io_queue_count_set,
+	.get = param_get_uint,
+};
+
+static unsigned int write_queues;
+module_param_cb(write_queues, &io_queue_count_ops, &write_queues, 0644);
+MODULE_PARM_DESC(write_queues,
+	"Number of queues to use for writes. If not set, reads and writes "
+	"will share a queue set.");
+
+static unsigned int poll_queues;
+module_param_cb(poll_queues, &io_queue_count_ops, &poll_queues, 0644);
+MODULE_PARM_DESC(poll_queues, "Number of queues to use for polled IO.");
+
+static bool noacpi;
+module_param(noacpi, bool, 0444);
+MODULE_PARM_DESC(noacpi, "disable acpi bios quirks");
+
+struct nvme_dev;
+struct nvme_queue;
+
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
+static void nvme_delete_io_queues(struct nvme_dev *dev);
+static void nvme_update_attrs(struct nvme_dev *dev);
+
+/*
+ * Represents an NVM Express device.  Each nvme_dev is a PCI function.
+ */
+struct nvme_dev {
+	struct nvme_queue *queues;
+	struct blk_mq_tag_set tagset;
+	struct blk_mq_tag_set admin_tagset;
+	u32 __iomem *dbs;
+	struct device *dev;
+	struct dma_pool *prp_page_pool;
+	struct dma_pool *prp_small_pool;
+	unsigned online_queues;
+	unsigned max_qid;
+	unsigned io_queues[HCTX_MAX_TYPES];
+	unsigned int num_vecs;
+	u32 q_depth;
+	int io_sqes;
+	u32 db_stride;
+	void __iomem *bar;
+	unsigned long bar_mapped_size;
+	struct mutex shutdown_lock;
+	bool subsystem;
+	u64 cmb_size;
+	bool cmb_use_sqes;
+	u32 cmbsz;
+	u32 cmbloc;
+	struct nvme_ctrl ctrl;
+	u32 last_ps;
+	bool hmb;
+
+	mempool_t *iod_mempool;
+
+	/* shadow doorbell buffer support: */
+	__le32 *dbbuf_dbs;
+	dma_addr_t dbbuf_dbs_dma_addr;
+	__le32 *dbbuf_eis;
+	dma_addr_t dbbuf_eis_dma_addr;
+
+	/* host memory buffer support: */
+	u64 host_mem_size;
+	u32 nr_host_mem_descs;
+	dma_addr_t host_mem_descs_dma;
+	struct nvme_host_mem_buf_desc *host_mem_descs;
+	void **host_mem_desc_bufs;
+	unsigned int nr_allocated_queues;
+	unsigned int nr_write_queues;
+	unsigned int nr_poll_queues;
+};
+
+static int io_queue_depth_set(const char *val, const struct kernel_param *kp)
+{
+	return param_set_uint_minmax(val, kp, NVME_PCI_MIN_QUEUE_SIZE,
+			NVME_PCI_MAX_QUEUE_SIZE);
+}
+
+static inline unsigned int sq_idx(unsigned int qid, u32 stride)
+{
+	return qid * 2 * stride;
+}
+
+static inline unsigned int cq_idx(unsigned int qid, u32 stride)
+{
+	return (qid * 2 + 1) * stride;
+}
+
+static inline struct nvme_dev *to_nvme_dev(struct nvme_ctrl *ctrl)
+{
+	return container_of(ctrl, struct nvme_dev, ctrl);
+}
+
+/*
+ * An NVM Express queue.  Each device has at least two (one for admin
+ * commands and one for I/O commands).
+ */
+struct nvme_queue {
+	struct nvme_dev *dev;
+	spinlock_t sq_lock;
+	void *sq_cmds;
+	 /* only used for poll queues: */
+	spinlock_t cq_poll_lock ____cacheline_aligned_in_smp;
+	struct nvme_completion *cqes;
+	dma_addr_t sq_dma_addr;
+	dma_addr_t cq_dma_addr;
+	u32 __iomem *q_db;
+	u32 q_depth;
+	u16 cq_vector;
+	u16 sq_tail;
+	u16 last_sq_tail;
+	u16 cq_head;
+	u16 qid;
+	u8 cq_phase;
+	u8 sqes;
+	unsigned long flags;
+#define NVMEQ_ENABLED		0
+#define NVMEQ_SQ_CMB		1
+#define NVMEQ_DELETE_ERROR	2
+#define NVMEQ_POLLED		3
+	__le32 *dbbuf_sq_db;
+	__le32 *dbbuf_cq_db;
+	__le32 *dbbuf_sq_ei;
+	__le32 *dbbuf_cq_ei;
+	struct completion delete_done;
+};
+
+union nvme_descriptor {
+	struct nvme_sgl_desc	*sg_list;
+	__le64			*prp_list;
+};
+
+/*
+ * The nvme_iod describes the data in an I/O.
+ *
+ * The sg pointer contains the list of PRP/SGL chunk allocations in addition
+ * to the actual struct scatterlist.
+ */
+struct nvme_iod {
+	struct nvme_request req;
+	struct nvme_command cmd;
+	bool aborted;
+	s8 nr_allocations;	/* PRP list pool allocations. 0 means small
+				   pool in use */
+	unsigned int dma_len;	/* length of single DMA segment mapping */
+	dma_addr_t first_dma;
+	dma_addr_t meta_dma;
+	struct sg_table sgt;
+	union nvme_descriptor list[NVME_MAX_NR_ALLOCATIONS];
+};
+
+static inline unsigned int nvme_dbbuf_size(struct nvme_dev *dev)
+{
+	return dev->nr_allocated_queues * 8 * dev->db_stride;
+}
+
+static void nvme_dbbuf_dma_alloc(struct nvme_dev *dev)
+{
+	unsigned int mem_size = nvme_dbbuf_size(dev);
+
+	if (!(dev->ctrl.oacs & NVME_CTRL_OACS_DBBUF_SUPP))
+		return;
+
+	if (dev->dbbuf_dbs) {
+		/*
+		 * Clear the dbbuf memory so the driver doesn't observe stale
+		 * values from the previous instantiation.
+		 */
+		memset(dev->dbbuf_dbs, 0, mem_size);
+		memset(dev->dbbuf_eis, 0, mem_size);
+		return;
+	}
+
+	dev->dbbuf_dbs = dma_alloc_coherent(dev->dev, mem_size,
+					    &dev->dbbuf_dbs_dma_addr,
+					    GFP_KERNEL);
+	if (!dev->dbbuf_dbs)
+		goto fail;
+	dev->dbbuf_eis = dma_alloc_coherent(dev->dev, mem_size,
+					    &dev->dbbuf_eis_dma_addr,
+					    GFP_KERNEL);
+	if (!dev->dbbuf_eis)
+		goto fail_free_dbbuf_dbs;
+	return;
+
+fail_free_dbbuf_dbs:
+	dma_free_coherent(dev->dev, mem_size, dev->dbbuf_dbs,
+			  dev->dbbuf_dbs_dma_addr);
+	dev->dbbuf_dbs = NULL;
+fail:
+	dev_warn(dev->dev, "unable to allocate dma for dbbuf\n");
+}
+
+static void nvme_dbbuf_dma_free(struct nvme_dev *dev)
+{
+	unsigned int mem_size = nvme_dbbuf_size(dev);
+
+	if (dev->dbbuf_dbs) {
+		dma_free_coherent(dev->dev, mem_size,
+				  dev->dbbuf_dbs, dev->dbbuf_dbs_dma_addr);
+		dev->dbbuf_dbs = NULL;
+	}
+	if (dev->dbbuf_eis) {
+		dma_free_coherent(dev->dev, mem_size,
+				  dev->dbbuf_eis, dev->dbbuf_eis_dma_addr);
+		dev->dbbuf_eis = NULL;
+	}
+}
+
+static void nvme_dbbuf_init(struct nvme_dev *dev,
+			    struct nvme_queue *nvmeq, int qid)
+{
+	if (!dev->dbbuf_dbs || !qid)
+		return;
+
+	nvmeq->dbbuf_sq_db = &dev->dbbuf_dbs[sq_idx(qid, dev->db_stride)];
+	nvmeq->dbbuf_cq_db = &dev->dbbuf_dbs[cq_idx(qid, dev->db_stride)];
+	nvmeq->dbbuf_sq_ei = &dev->dbbuf_eis[sq_idx(qid, dev->db_stride)];
+	nvmeq->dbbuf_cq_ei = &dev->dbbuf_eis[cq_idx(qid, dev->db_stride)];
+}
+
+static void nvme_dbbuf_free(struct nvme_queue *nvmeq)
+{
+	if (!nvmeq->qid)
+		return;
+
+	nvmeq->dbbuf_sq_db = NULL;
+	nvmeq->dbbuf_cq_db = NULL;
+	nvmeq->dbbuf_sq_ei = NULL;
+	nvmeq->dbbuf_cq_ei = NULL;
+}
+
+static void nvme_dbbuf_set(struct nvme_dev *dev)
+{
+	struct nvme_command c = { };
+	unsigned int i;
+
+	if (!dev->dbbuf_dbs)
+		return;
+
+	c.dbbuf.opcode = nvme_admin_dbbuf;
+	c.dbbuf.prp1 = cpu_to_le64(dev->dbbuf_dbs_dma_addr);
+	c.dbbuf.prp2 = cpu_to_le64(dev->dbbuf_eis_dma_addr);
+
+	if (nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0)) {
+		dev_warn(dev->ctrl.device, "unable to set dbbuf\n");
+		/* Free memory and continue on */
+		nvme_dbbuf_dma_free(dev);
+
+		for (i = 1; i <= dev->online_queues; i++)
+			nvme_dbbuf_free(&dev->queues[i]);
+	}
+}
+
+static inline int nvme_dbbuf_need_event(u16 event_idx, u16 new_idx, u16 old)
+{
+	return (u16)(new_idx - event_idx - 1) < (u16)(new_idx - old);
+}
+
+/* Update dbbuf and return true if an MMIO is required */
+static bool nvme_dbbuf_update_and_check_event(u16 value, __le32 *dbbuf_db,
+					      volatile __le32 *dbbuf_ei)
+{
+	if (dbbuf_db) {
+		u16 old_value, event_idx;
+
+		/*
+		 * Ensure that the queue is written before updating
+		 * the doorbell in memory
+		 */
+		wmb();
+
+		old_value = le32_to_cpu(*dbbuf_db);
+		*dbbuf_db = cpu_to_le32(value);
+
+		/*
+		 * Ensure that the doorbell is updated before reading the event
+		 * index from memory.  The controller needs to provide similar
+		 * ordering to ensure the envent index is updated before reading
+		 * the doorbell.
+		 */
+		mb();
+
+		event_idx = le32_to_cpu(*dbbuf_ei);
+		if (!nvme_dbbuf_need_event(event_idx, value, old_value))
+			return false;
+	}
+
+	return true;
+}
+
+/*
+ * Will slightly overestimate the number of pages needed.  This is OK
+ * as it only leads to a small amount of wasted memory for the lifetime of
+ * the I/O.
+ */
+static int nvme_pci_npages_prp(void)
+{
+	unsigned max_bytes = (NVME_MAX_KB_SZ * 1024) + NVME_CTRL_PAGE_SIZE;
+	unsigned nprps = DIV_ROUND_UP(max_bytes, NVME_CTRL_PAGE_SIZE);
+	return DIV_ROUND_UP(8 * nprps, NVME_CTRL_PAGE_SIZE - 8);
+}
+
+static int nvme_admin_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+				unsigned int hctx_idx)
+{
+	struct nvme_dev *dev = to_nvme_dev(data);
+	struct nvme_queue *nvmeq = &dev->queues[0];
+
+	WARN_ON(hctx_idx != 0);
+	WARN_ON(dev->admin_tagset.tags[0] != hctx->tags);
+
+	hctx->driver_data = nvmeq;
+	return 0;
+}
+
+static int nvme_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+			  unsigned int hctx_idx)
+{
+	struct nvme_dev *dev = to_nvme_dev(data);
+	struct nvme_queue *nvmeq = &dev->queues[hctx_idx + 1];
+
+	WARN_ON(dev->tagset.tags[hctx_idx] != hctx->tags);
+	hctx->driver_data = nvmeq;
+	return 0;
+}
+
+static int nvme_pci_init_request(struct blk_mq_tag_set *set,
+		struct request *req, unsigned int hctx_idx,
+		unsigned int numa_node)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+	nvme_req(req)->ctrl = set->driver_data;
+	nvme_req(req)->cmd = &iod->cmd;
+	return 0;
+}
+
+static int queue_irq_offset(struct nvme_dev *dev)
+{
+	/* if we have more than 1 vec, admin queue offsets us by 1 */
+	if (dev->num_vecs > 1)
+		return 1;
+
+	return 0;
+}
+
+static void nvme_pci_map_queues(struct blk_mq_tag_set *set)
+{
+	struct nvme_dev *dev = to_nvme_dev(set->driver_data);
+	int i, qoff, offset;
+
+	offset = queue_irq_offset(dev);
+	for (i = 0, qoff = 0; i < set->nr_maps; i++) {
+		struct blk_mq_queue_map *map = &set->map[i];
+
+		map->nr_queues = dev->io_queues[i];
+		if (!map->nr_queues) {
+			BUG_ON(i == HCTX_TYPE_DEFAULT);
+			continue;
+		}
+
+		/*
+		 * The poll queue(s) doesn't have an IRQ (and hence IRQ
+		 * affinity), so use the regular blk-mq cpu mapping
+		 */
+		map->queue_offset = qoff;
+		if (i != HCTX_TYPE_POLL && offset)
+			blk_mq_pci_map_queues(map, to_pci_dev(dev->dev), offset);
+		else
+			blk_mq_map_queues(map);
+		qoff += map->nr_queues;
+		offset += map->nr_queues;
+	}
+}
+
+/*
+ * Write sq tail if we are asked to, or if the next command would wrap.
+ */
+static inline void nvme_write_sq_db(struct nvme_queue *nvmeq, bool write_sq)
+{
+	if (!write_sq) {
+		u16 next_tail = nvmeq->sq_tail + 1;
+
+		if (next_tail == nvmeq->q_depth)
+			next_tail = 0;
+		if (next_tail != nvmeq->last_sq_tail)
+			return;
+	}
+
+	if (nvme_dbbuf_update_and_check_event(nvmeq->sq_tail,
+			nvmeq->dbbuf_sq_db, nvmeq->dbbuf_sq_ei))
+		writel(nvmeq->sq_tail, nvmeq->q_db);
+	nvmeq->last_sq_tail = nvmeq->sq_tail;
+}
+
+static inline void nvme_sq_copy_cmd(struct nvme_queue *nvmeq,
+				    struct nvme_command *cmd)
+{
+	memcpy(nvmeq->sq_cmds + (nvmeq->sq_tail << nvmeq->sqes),
+		absolute_pointer(cmd), sizeof(*cmd));
+	if (++nvmeq->sq_tail == nvmeq->q_depth)
+		nvmeq->sq_tail = 0;
+}
+
+static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx)
+{
+	struct nvme_queue *nvmeq = hctx->driver_data;
+
+	spin_lock(&nvmeq->sq_lock);
+	if (nvmeq->sq_tail != nvmeq->last_sq_tail)
+		nvme_write_sq_db(nvmeq, true);
+	spin_unlock(&nvmeq->sq_lock);
+}
+
+static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req,
+				     int nseg)
+{
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+	unsigned int avg_seg_size;
+
+	avg_seg_size = DIV_ROUND_UP(blk_rq_payload_bytes(req), nseg);
+
+	if (!nvme_ctrl_sgl_supported(&dev->ctrl))
+		return false;
+	if (!nvmeq->qid)
+		return false;
+	if (!sgl_threshold || avg_seg_size < sgl_threshold)
+		return false;
+	return true;
+}
+
+static void nvme_free_prps(struct nvme_dev *dev, struct request *req)
+{
+	const int last_prp = NVME_CTRL_PAGE_SIZE / sizeof(__le64) - 1;
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	dma_addr_t dma_addr = iod->first_dma;
+	int i;
+
+	for (i = 0; i < iod->nr_allocations; i++) {
+		__le64 *prp_list = iod->list[i].prp_list;
+		dma_addr_t next_dma_addr = le64_to_cpu(prp_list[last_prp]);
+
+		dma_pool_free(dev->prp_page_pool, prp_list, dma_addr);
+		dma_addr = next_dma_addr;
+	}
+}
+
+static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+	if (iod->dma_len) {
+		dma_unmap_page(dev->dev, iod->first_dma, iod->dma_len,
+			       rq_dma_dir(req));
+		return;
+	}
+
+	WARN_ON_ONCE(!iod->sgt.nents);
+
+	dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);
+
+	if (iod->nr_allocations == 0)
+		dma_pool_free(dev->prp_small_pool, iod->list[0].sg_list,
+			      iod->first_dma);
+	else if (iod->nr_allocations == 1)
+		dma_pool_free(dev->prp_page_pool, iod->list[0].sg_list,
+			      iod->first_dma);
+	else
+		nvme_free_prps(dev, req);
+	mempool_free(iod->sgt.sgl, dev->iod_mempool);
+}
+
+static void nvme_print_sgl(struct scatterlist *sgl, int nents)
+{
+	int i;
+	struct scatterlist *sg;
+
+	for_each_sg(sgl, sg, nents, i) {
+		dma_addr_t phys = sg_phys(sg);
+		pr_warn("sg[%d] phys_addr:%pad offset:%d length:%d "
+			"dma_address:%pad dma_length:%d\n",
+			i, &phys, sg->offset, sg->length, &sg_dma_address(sg),
+			sg_dma_len(sg));
+	}
+}
+
+static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
+		struct request *req, struct nvme_rw_command *cmnd)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	struct dma_pool *pool;
+	int length = blk_rq_payload_bytes(req);
+	struct scatterlist *sg = iod->sgt.sgl;
+	int dma_len = sg_dma_len(sg);
+	u64 dma_addr = sg_dma_address(sg);
+	int offset = dma_addr & (NVME_CTRL_PAGE_SIZE - 1);
+	__le64 *prp_list;
+	dma_addr_t prp_dma;
+	int nprps, i;
+
+	length -= (NVME_CTRL_PAGE_SIZE - offset);
+	if (length <= 0) {
+		iod->first_dma = 0;
+		goto done;
+	}
+
+	dma_len -= (NVME_CTRL_PAGE_SIZE - offset);
+	if (dma_len) {
+		dma_addr += (NVME_CTRL_PAGE_SIZE - offset);
+	} else {
+		sg = sg_next(sg);
+		dma_addr = sg_dma_address(sg);
+		dma_len = sg_dma_len(sg);
+	}
+
+	if (length <= NVME_CTRL_PAGE_SIZE) {
+		iod->first_dma = dma_addr;
+		goto done;
+	}
+
+	nprps = DIV_ROUND_UP(length, NVME_CTRL_PAGE_SIZE);
+	if (nprps <= (256 / 8)) {
+		pool = dev->prp_small_pool;
+		iod->nr_allocations = 0;
+	} else {
+		pool = dev->prp_page_pool;
+		iod->nr_allocations = 1;
+	}
+
+	prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
+	if (!prp_list) {
+		iod->nr_allocations = -1;
+		return BLK_STS_RESOURCE;
+	}
+	iod->list[0].prp_list = prp_list;
+	iod->first_dma = prp_dma;
+	i = 0;
+	for (;;) {
+		if (i == NVME_CTRL_PAGE_SIZE >> 3) {
+			__le64 *old_prp_list = prp_list;
+			prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
+			if (!prp_list)
+				goto free_prps;
+			iod->list[iod->nr_allocations++].prp_list = prp_list;
+			prp_list[0] = old_prp_list[i - 1];
+			old_prp_list[i - 1] = cpu_to_le64(prp_dma);
+			i = 1;
+		}
+		prp_list[i++] = cpu_to_le64(dma_addr);
+		dma_len -= NVME_CTRL_PAGE_SIZE;
+		dma_addr += NVME_CTRL_PAGE_SIZE;
+		length -= NVME_CTRL_PAGE_SIZE;
+		if (length <= 0)
+			break;
+		if (dma_len > 0)
+			continue;
+		if (unlikely(dma_len < 0))
+			goto bad_sgl;
+		sg = sg_next(sg);
+		dma_addr = sg_dma_address(sg);
+		dma_len = sg_dma_len(sg);
+	}
+done:
+	cmnd->dptr.prp1 = cpu_to_le64(sg_dma_address(iod->sgt.sgl));
+	cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma);
+	return BLK_STS_OK;
+free_prps:
+	nvme_free_prps(dev, req);
+	return BLK_STS_RESOURCE;
+bad_sgl:
+	WARN(DO_ONCE(nvme_print_sgl, iod->sgt.sgl, iod->sgt.nents),
+			"Invalid SGL for payload:%d nents:%d\n",
+			blk_rq_payload_bytes(req), iod->sgt.nents);
+	return BLK_STS_IOERR;
+}
+
+static void nvme_pci_sgl_set_data(struct nvme_sgl_desc *sge,
+		struct scatterlist *sg)
+{
+	sge->addr = cpu_to_le64(sg_dma_address(sg));
+	sge->length = cpu_to_le32(sg_dma_len(sg));
+	sge->type = NVME_SGL_FMT_DATA_DESC << 4;
+}
+
+static void nvme_pci_sgl_set_seg(struct nvme_sgl_desc *sge,
+		dma_addr_t dma_addr, int entries)
+{
+	sge->addr = cpu_to_le64(dma_addr);
+	sge->length = cpu_to_le32(entries * sizeof(*sge));
+	sge->type = NVME_SGL_FMT_LAST_SEG_DESC << 4;
+}
+
+static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
+		struct request *req, struct nvme_rw_command *cmd)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	struct dma_pool *pool;
+	struct nvme_sgl_desc *sg_list;
+	struct scatterlist *sg = iod->sgt.sgl;
+	unsigned int entries = iod->sgt.nents;
+	dma_addr_t sgl_dma;
+	int i = 0;
+
+	/* setting the transfer type as SGL */
+	cmd->flags = NVME_CMD_SGL_METABUF;
+
+	if (entries == 1) {
+		nvme_pci_sgl_set_data(&cmd->dptr.sgl, sg);
+		return BLK_STS_OK;
+	}
+
+	if (entries <= (256 / sizeof(struct nvme_sgl_desc))) {
+		pool = dev->prp_small_pool;
+		iod->nr_allocations = 0;
+	} else {
+		pool = dev->prp_page_pool;
+		iod->nr_allocations = 1;
+	}
+
+	sg_list = dma_pool_alloc(pool, GFP_ATOMIC, &sgl_dma);
+	if (!sg_list) {
+		iod->nr_allocations = -1;
+		return BLK_STS_RESOURCE;
+	}
+
+	iod->list[0].sg_list = sg_list;
+	iod->first_dma = sgl_dma;
+
+	nvme_pci_sgl_set_seg(&cmd->dptr.sgl, sgl_dma, entries);
+	do {
+		nvme_pci_sgl_set_data(&sg_list[i++], sg);
+		sg = sg_next(sg);
+	} while (--entries > 0);
+
+	return BLK_STS_OK;
+}
+
+static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev,
+		struct request *req, struct nvme_rw_command *cmnd,
+		struct bio_vec *bv)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	unsigned int offset = bv->bv_offset & (NVME_CTRL_PAGE_SIZE - 1);
+	unsigned int first_prp_len = NVME_CTRL_PAGE_SIZE - offset;
+
+	iod->first_dma = dma_map_bvec(dev->dev, bv, rq_dma_dir(req), 0);
+	if (dma_mapping_error(dev->dev, iod->first_dma))
+		return BLK_STS_RESOURCE;
+	iod->dma_len = bv->bv_len;
+
+	cmnd->dptr.prp1 = cpu_to_le64(iod->first_dma);
+	if (bv->bv_len > first_prp_len)
+		cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma + first_prp_len);
+	else
+		cmnd->dptr.prp2 = 0;
+	return BLK_STS_OK;
+}
+
+static blk_status_t nvme_setup_sgl_simple(struct nvme_dev *dev,
+		struct request *req, struct nvme_rw_command *cmnd,
+		struct bio_vec *bv)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+	iod->first_dma = dma_map_bvec(dev->dev, bv, rq_dma_dir(req), 0);
+	if (dma_mapping_error(dev->dev, iod->first_dma))
+		return BLK_STS_RESOURCE;
+	iod->dma_len = bv->bv_len;
+
+	cmnd->flags = NVME_CMD_SGL_METABUF;
+	cmnd->dptr.sgl.addr = cpu_to_le64(iod->first_dma);
+	cmnd->dptr.sgl.length = cpu_to_le32(iod->dma_len);
+	cmnd->dptr.sgl.type = NVME_SGL_FMT_DATA_DESC << 4;
+	return BLK_STS_OK;
+}
+
+static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
+		struct nvme_command *cmnd)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	blk_status_t ret = BLK_STS_RESOURCE;
+	int rc;
+
+	if (blk_rq_nr_phys_segments(req) == 1) {
+		struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+		struct bio_vec bv = req_bvec(req);
+
+		if (!is_pci_p2pdma_page(bv.bv_page)) {
+			if (bv.bv_offset + bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
+				return nvme_setup_prp_simple(dev, req,
+							     &cmnd->rw, &bv);
+
+			if (nvmeq->qid && sgl_threshold &&
+			    nvme_ctrl_sgl_supported(&dev->ctrl))
+				return nvme_setup_sgl_simple(dev, req,
+							     &cmnd->rw, &bv);
+		}
+	}
+
+	iod->dma_len = 0;
+	iod->sgt.sgl = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
+	if (!iod->sgt.sgl)
+		return BLK_STS_RESOURCE;
+	sg_init_table(iod->sgt.sgl, blk_rq_nr_phys_segments(req));
+	iod->sgt.orig_nents = blk_rq_map_sg(req->q, req, iod->sgt.sgl);
+	if (!iod->sgt.orig_nents)
+		goto out_free_sg;
+
+	rc = dma_map_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req),
+			     DMA_ATTR_NO_WARN);
+	if (rc) {
+		if (rc == -EREMOTEIO)
+			ret = BLK_STS_TARGET;
+		goto out_free_sg;
+	}
+
+	if (nvme_pci_use_sgls(dev, req, iod->sgt.nents))
+		ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw);
+	else
+		ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);
+	if (ret != BLK_STS_OK)
+		goto out_unmap_sg;
+	return BLK_STS_OK;
+
+out_unmap_sg:
+	dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);
+out_free_sg:
+	mempool_free(iod->sgt.sgl, dev->iod_mempool);
+	return ret;
+}
+
+static blk_status_t nvme_map_metadata(struct nvme_dev *dev, struct request *req,
+		struct nvme_command *cmnd)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+	iod->meta_dma = dma_map_bvec(dev->dev, rq_integrity_vec(req),
+			rq_dma_dir(req), 0);
+	if (dma_mapping_error(dev->dev, iod->meta_dma))
+		return BLK_STS_IOERR;
+	cmnd->rw.metadata = cpu_to_le64(iod->meta_dma);
+	return BLK_STS_OK;
+}
+
+static blk_status_t nvme_prep_rq(struct nvme_dev *dev, struct request *req)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	blk_status_t ret;
+
+	iod->aborted = false;
+	iod->nr_allocations = -1;
+	iod->sgt.nents = 0;
+
+	ret = nvme_setup_cmd(req->q->queuedata, req);
+	if (ret)
+		return ret;
+
+	if (blk_rq_nr_phys_segments(req)) {
+		ret = nvme_map_data(dev, req, &iod->cmd);
+		if (ret)
+			goto out_free_cmd;
+	}
+
+	if (blk_integrity_rq(req)) {
+		ret = nvme_map_metadata(dev, req, &iod->cmd);
+		if (ret)
+			goto out_unmap_data;
+	}
+
+	nvme_start_request(req);
+	return BLK_STS_OK;
+out_unmap_data:
+	nvme_unmap_data(dev, req);
+out_free_cmd:
+	nvme_cleanup_cmd(req);
+	return ret;
+}
+
+/*
+ * NOTE: ns is NULL when called on the admin queue.
+ */
+static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
+			 const struct blk_mq_queue_data *bd)
+{
+	struct nvme_queue *nvmeq = hctx->driver_data;
+	struct nvme_dev *dev = nvmeq->dev;
+	struct request *req = bd->rq;
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	blk_status_t ret;
+
+	/*
+	 * We should not need to do this, but we're still using this to
+	 * ensure we can drain requests on a dying queue.
+	 */
+	if (unlikely(!test_bit(NVMEQ_ENABLED, &nvmeq->flags)))
+		return BLK_STS_IOERR;
+
+	if (unlikely(!nvme_check_ready(&dev->ctrl, req, true)))
+		return nvme_fail_nonready_command(&dev->ctrl, req);
+
+	ret = nvme_prep_rq(dev, req);
+	if (unlikely(ret))
+		return ret;
+	spin_lock(&nvmeq->sq_lock);
+	nvme_sq_copy_cmd(nvmeq, &iod->cmd);
+	nvme_write_sq_db(nvmeq, bd->last);
+	spin_unlock(&nvmeq->sq_lock);
+	return BLK_STS_OK;
+}
+
+static void nvme_submit_cmds(struct nvme_queue *nvmeq, struct request **rqlist)
+{
+	spin_lock(&nvmeq->sq_lock);
+	while (!rq_list_empty(*rqlist)) {
+		struct request *req = rq_list_pop(rqlist);
+		struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+		nvme_sq_copy_cmd(nvmeq, &iod->cmd);
+	}
+	nvme_write_sq_db(nvmeq, true);
+	spin_unlock(&nvmeq->sq_lock);
+}
+
+static bool nvme_prep_rq_batch(struct nvme_queue *nvmeq, struct request *req)
+{
+	/*
+	 * We should not need to do this, but we're still using this to
+	 * ensure we can drain requests on a dying queue.
+	 */
+	if (unlikely(!test_bit(NVMEQ_ENABLED, &nvmeq->flags)))
+		return false;
+	if (unlikely(!nvme_check_ready(&nvmeq->dev->ctrl, req, true)))
+		return false;
+
+	req->mq_hctx->tags->rqs[req->tag] = req;
+	return nvme_prep_rq(nvmeq->dev, req) == BLK_STS_OK;
+}
+
+static void nvme_queue_rqs(struct request **rqlist)
+{
+	struct request *req, *next, *prev = NULL;
+	struct request *requeue_list = NULL;
+
+	rq_list_for_each_safe(rqlist, req, next) {
+		struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+
+		if (!nvme_prep_rq_batch(nvmeq, req)) {
+			/* detach 'req' and add to remainder list */
+			rq_list_move(rqlist, &requeue_list, req, prev);
+
+			req = prev;
+			if (!req)
+				continue;
+		}
+
+		if (!next || req->mq_hctx != next->mq_hctx) {
+			/* detach rest of list, and submit */
+			req->rq_next = NULL;
+			nvme_submit_cmds(nvmeq, rqlist);
+			*rqlist = next;
+			prev = NULL;
+		} else
+			prev = req;
+	}
+
+	*rqlist = requeue_list;
+}
+
+static __always_inline void nvme_pci_unmap_rq(struct request *req)
+{
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+	struct nvme_dev *dev = nvmeq->dev;
+
+	if (blk_integrity_rq(req)) {
+	        struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+		dma_unmap_page(dev->dev, iod->meta_dma,
+			       rq_integrity_vec(req)->bv_len, rq_dma_dir(req));
+	}
+
+	if (blk_rq_nr_phys_segments(req))
+		nvme_unmap_data(dev, req);
+}
+
+static void nvme_pci_complete_rq(struct request *req)
+{
+	nvme_pci_unmap_rq(req);
+	nvme_complete_rq(req);
+}
+
+static void nvme_pci_complete_batch(struct io_comp_batch *iob)
+{
+	nvme_complete_batch(iob, nvme_pci_unmap_rq);
+}
+
+/* We read the CQE phase first to check if the rest of the entry is valid */
+static inline bool nvme_cqe_pending(struct nvme_queue *nvmeq)
+{
+	struct nvme_completion *hcqe = &nvmeq->cqes[nvmeq->cq_head];
+
+	return (le16_to_cpu(READ_ONCE(hcqe->status)) & 1) == nvmeq->cq_phase;
+}
+
+static inline void nvme_ring_cq_doorbell(struct nvme_queue *nvmeq)
+{
+	u16 head = nvmeq->cq_head;
+
+	if (nvme_dbbuf_update_and_check_event(head, nvmeq->dbbuf_cq_db,
+					      nvmeq->dbbuf_cq_ei))
+		writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
+}
+
+static inline struct blk_mq_tags *nvme_queue_tagset(struct nvme_queue *nvmeq)
+{
+	if (!nvmeq->qid)
+		return nvmeq->dev->admin_tagset.tags[0];
+	return nvmeq->dev->tagset.tags[nvmeq->qid - 1];
+}
+
+static inline void nvme_handle_cqe(struct nvme_queue *nvmeq,
+				   struct io_comp_batch *iob, u16 idx)
+{
+	struct nvme_completion *cqe = &nvmeq->cqes[idx];
+	__u16 command_id = READ_ONCE(cqe->command_id);
+	struct request *req;
+
+	/*
+	 * AEN requests are special as they don't time out and can
+	 * survive any kind of queue freeze and often don't respond to
+	 * aborts.  We don't even bother to allocate a struct request
+	 * for them but rather special case them here.
+	 */
+	if (unlikely(nvme_is_aen_req(nvmeq->qid, command_id))) {
+		nvme_complete_async_event(&nvmeq->dev->ctrl,
+				cqe->status, &cqe->result);
+		return;
+	}
+
+	req = nvme_find_rq(nvme_queue_tagset(nvmeq), command_id);
+	if (unlikely(!req)) {
+		dev_warn(nvmeq->dev->ctrl.device,
+			"invalid id %d completed on queue %d\n",
+			command_id, le16_to_cpu(cqe->sq_id));
+		return;
+	}
+
+	trace_nvme_sq(req, cqe->sq_head, nvmeq->sq_tail);
+	if (!nvme_try_complete_req(req, cqe->status, cqe->result) &&
+	    !blk_mq_add_to_batch(req, iob, nvme_req(req)->status,
+					nvme_pci_complete_batch))
+		nvme_pci_complete_rq(req);
+}
+
+static inline void nvme_update_cq_head(struct nvme_queue *nvmeq)
+{
+	u32 tmp = nvmeq->cq_head + 1;
+
+	if (tmp == nvmeq->q_depth) {
+		nvmeq->cq_head = 0;
+		nvmeq->cq_phase ^= 1;
+	} else {
+		nvmeq->cq_head = tmp;
+	}
+}
+
+static inline int nvme_poll_cq(struct nvme_queue *nvmeq,
+			       struct io_comp_batch *iob)
+{
+	int found = 0;
+
+	while (nvme_cqe_pending(nvmeq)) {
+		found++;
+		/*
+		 * load-load control dependency between phase and the rest of
+		 * the cqe requires a full read memory barrier
+		 */
+		dma_rmb();
+		nvme_handle_cqe(nvmeq, iob, nvmeq->cq_head);
+		nvme_update_cq_head(nvmeq);
+	}
+
+	if (found)
+		nvme_ring_cq_doorbell(nvmeq);
+	return found;
+}
+
+static irqreturn_t nvme_irq(int irq, void *data)
+{
+	struct nvme_queue *nvmeq = data;
+	DEFINE_IO_COMP_BATCH(iob);
+
+	if (nvme_poll_cq(nvmeq, &iob)) {
+		if (!rq_list_empty(iob.req_list))
+			nvme_pci_complete_batch(&iob);
+		return IRQ_HANDLED;
+	}
+	return IRQ_NONE;
+}
+
+static irqreturn_t nvme_irq_check(int irq, void *data)
+{
+	struct nvme_queue *nvmeq = data;
+
+	if (nvme_cqe_pending(nvmeq))
+		return IRQ_WAKE_THREAD;
+	return IRQ_NONE;
+}
+
+/*
+ * Poll for completions for any interrupt driven queue
+ * Can be called from any context.
+ */
+static void nvme_poll_irqdisable(struct nvme_queue *nvmeq)
+{
+	struct pci_dev *pdev = to_pci_dev(nvmeq->dev->dev);
+
+	WARN_ON_ONCE(test_bit(NVMEQ_POLLED, &nvmeq->flags));
+
+	disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));
+	nvme_poll_cq(nvmeq, NULL);
+	enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));
+}
+
+static int nvme_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
+{
+	struct nvme_queue *nvmeq = hctx->driver_data;
+	bool found;
+
+	if (!nvme_cqe_pending(nvmeq))
+		return 0;
+
+	spin_lock(&nvmeq->cq_poll_lock);
+	found = nvme_poll_cq(nvmeq, iob);
+	spin_unlock(&nvmeq->cq_poll_lock);
+
+	return found;
+}
+
+static void nvme_pci_submit_async_event(struct nvme_ctrl *ctrl)
+{
+	struct nvme_dev *dev = to_nvme_dev(ctrl);
+	struct nvme_queue *nvmeq = &dev->queues[0];
+	struct nvme_command c = { };
+
+	c.common.opcode = nvme_admin_async_event;
+	c.common.command_id = NVME_AQ_BLK_MQ_DEPTH;
+
+	spin_lock(&nvmeq->sq_lock);
+	nvme_sq_copy_cmd(nvmeq, &c);
+	nvme_write_sq_db(nvmeq, true);
+	spin_unlock(&nvmeq->sq_lock);
+}
+
+static int adapter_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)
+{
+	struct nvme_command c = { };
+
+	c.delete_queue.opcode = opcode;
+	c.delete_queue.qid = cpu_to_le16(id);
+
+	return nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0);
+}
+
+static int adapter_alloc_cq(struct nvme_dev *dev, u16 qid,
+		struct nvme_queue *nvmeq, s16 vector)
+{
+	struct nvme_command c = { };
+	int flags = NVME_QUEUE_PHYS_CONTIG;
+
+	if (!test_bit(NVMEQ_POLLED, &nvmeq->flags))
+		flags |= NVME_CQ_IRQ_ENABLED;
+
+	/*
+	 * Note: we (ab)use the fact that the prp fields survive if no data
+	 * is attached to the request.
+	 */
+	c.create_cq.opcode = nvme_admin_create_cq;
+	c.create_cq.prp1 = cpu_to_le64(nvmeq->cq_dma_addr);
+	c.create_cq.cqid = cpu_to_le16(qid);
+	c.create_cq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
+	c.create_cq.cq_flags = cpu_to_le16(flags);
+	c.create_cq.irq_vector = cpu_to_le16(vector);
+
+	return nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0);
+}
+
+static int adapter_alloc_sq(struct nvme_dev *dev, u16 qid,
+						struct nvme_queue *nvmeq)
+{
+	struct nvme_ctrl *ctrl = &dev->ctrl;
+	struct nvme_command c = { };
+	int flags = NVME_QUEUE_PHYS_CONTIG;
+
+	/*
+	 * Some drives have a bug that auto-enables WRRU if MEDIUM isn't
+	 * set. Since URGENT priority is zeroes, it makes all queues
+	 * URGENT.
+	 */
+	if (ctrl->quirks & NVME_QUIRK_MEDIUM_PRIO_SQ)
+		flags |= NVME_SQ_PRIO_MEDIUM;
+
+	/*
+	 * Note: we (ab)use the fact that the prp fields survive if no data
+	 * is attached to the request.
+	 */
+	c.create_sq.opcode = nvme_admin_create_sq;
+	c.create_sq.prp1 = cpu_to_le64(nvmeq->sq_dma_addr);
+	c.create_sq.sqid = cpu_to_le16(qid);
+	c.create_sq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
+	c.create_sq.sq_flags = cpu_to_le16(flags);
+	c.create_sq.cqid = cpu_to_le16(qid);
+
+	return nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0);
+}
+
+static int adapter_delete_cq(struct nvme_dev *dev, u16 cqid)
+{
+	return adapter_delete_queue(dev, nvme_admin_delete_cq, cqid);
+}
+
+static int adapter_delete_sq(struct nvme_dev *dev, u16 sqid)
+{
+	return adapter_delete_queue(dev, nvme_admin_delete_sq, sqid);
+}
+
+static enum rq_end_io_ret abort_endio(struct request *req, blk_status_t error)
+{
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+
+	dev_warn(nvmeq->dev->ctrl.device,
+		 "Abort status: 0x%x", nvme_req(req)->status);
+	atomic_inc(&nvmeq->dev->ctrl.abort_limit);
+	blk_mq_free_request(req);
+	return RQ_END_IO_NONE;
+}
+
+static bool nvme_should_reset(struct nvme_dev *dev, u32 csts)
+{
+	/* If true, indicates loss of adapter communication, possibly by a
+	 * NVMe Subsystem reset.
+	 */
+	bool nssro = dev->subsystem && (csts & NVME_CSTS_NSSRO);
+
+	/* If there is a reset/reinit ongoing, we shouldn't reset again. */
+	switch (nvme_ctrl_state(&dev->ctrl)) {
+	case NVME_CTRL_RESETTING:
+	case NVME_CTRL_CONNECTING:
+		return false;
+	default:
+		break;
+	}
+
+	/* We shouldn't reset unless the controller is on fatal error state
+	 * _or_ if we lost the communication with it.
+	 */
+	if (!(csts & NVME_CSTS_CFS) && !nssro)
+		return false;
+
+	return true;
+}
+
+static void nvme_warn_reset(struct nvme_dev *dev, u32 csts)
+{
+	/* Read a config register to help see what died. */
+	u16 pci_status;
+	int result;
+
+	result = pci_read_config_word(to_pci_dev(dev->dev), PCI_STATUS,
+				      &pci_status);
+	if (result == PCIBIOS_SUCCESSFUL)
+		dev_warn(dev->ctrl.device,
+			 "controller is down; will reset: CSTS=0x%x, PCI_STATUS=0x%hx\n",
+			 csts, pci_status);
+	else
+		dev_warn(dev->ctrl.device,
+			 "controller is down; will reset: CSTS=0x%x, PCI_STATUS read failed (%d)\n",
+			 csts, result);
+
+	if (csts != ~0)
+		return;
+
+	dev_warn(dev->ctrl.device,
+		 "Does your device have a faulty power saving mode enabled?\n");
+	dev_warn(dev->ctrl.device,
+		 "Try \"nvme_core.default_ps_max_latency_us=0 pcie_aspm=off\" and report a bug\n");
+}
+
+static enum blk_eh_timer_return nvme_timeout(struct request *req)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+	struct nvme_dev *dev = nvmeq->dev;
+	struct request *abort_req;
+	struct nvme_command cmd = { };
+	u32 csts = readl(dev->bar + NVME_REG_CSTS);
+
+	/* If PCI error recovery process is happening, we cannot reset or
+	 * the recovery mechanism will surely fail.
+	 */
+	mb();
+	if (pci_channel_offline(to_pci_dev(dev->dev)))
+		return BLK_EH_RESET_TIMER;
+
+	/*
+	 * Reset immediately if the controller is failed
+	 */
+	if (nvme_should_reset(dev, csts)) {
+		nvme_warn_reset(dev, csts);
+		goto disable;
+	}
+
+	/*
+	 * Did we miss an interrupt?
+	 */
+	if (test_bit(NVMEQ_POLLED, &nvmeq->flags))
+		nvme_poll(req->mq_hctx, NULL);
+	else
+		nvme_poll_irqdisable(nvmeq);
+
+	if (blk_mq_rq_state(req) != MQ_RQ_IN_FLIGHT) {
+		dev_warn(dev->ctrl.device,
+			 "I/O %d QID %d timeout, completion polled\n",
+			 req->tag, nvmeq->qid);
+		return BLK_EH_DONE;
+	}
+
+	/*
+	 * Shutdown immediately if controller times out while starting. The
+	 * reset work will see the pci device disabled when it gets the forced
+	 * cancellation error. All outstanding requests are completed on
+	 * shutdown, so we return BLK_EH_DONE.
+	 */
+	switch (nvme_ctrl_state(&dev->ctrl)) {
+	case NVME_CTRL_CONNECTING:
+		nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
+		fallthrough;
+	case NVME_CTRL_DELETING:
+		dev_warn_ratelimited(dev->ctrl.device,
+			 "I/O %d QID %d timeout, disable controller\n",
+			 req->tag, nvmeq->qid);
+		nvme_req(req)->flags |= NVME_REQ_CANCELLED;
+		nvme_dev_disable(dev, true);
+		return BLK_EH_DONE;
+	case NVME_CTRL_RESETTING:
+		return BLK_EH_RESET_TIMER;
+	default:
+		break;
+	}
+
+	/*
+	 * Shutdown the controller immediately and schedule a reset if the
+	 * command was already aborted once before and still hasn't been
+	 * returned to the driver, or if this is the admin queue.
+	 */
+	if (!nvmeq->qid || iod->aborted) {
+		dev_warn(dev->ctrl.device,
+			 "I/O %d QID %d timeout, reset controller\n",
+			 req->tag, nvmeq->qid);
+		nvme_req(req)->flags |= NVME_REQ_CANCELLED;
+		goto disable;
+	}
+
+	if (atomic_dec_return(&dev->ctrl.abort_limit) < 0) {
+		atomic_inc(&dev->ctrl.abort_limit);
+		return BLK_EH_RESET_TIMER;
+	}
+	iod->aborted = true;
+
+	cmd.abort.opcode = nvme_admin_abort_cmd;
+	cmd.abort.cid = nvme_cid(req);
+	cmd.abort.sqid = cpu_to_le16(nvmeq->qid);
+
+	dev_warn(nvmeq->dev->ctrl.device,
+		"I/O %d (%s) QID %d timeout, aborting\n",
+		 req->tag,
+		 nvme_get_opcode_str(nvme_req(req)->cmd->common.opcode),
+		 nvmeq->qid);
+
+	abort_req = blk_mq_alloc_request(dev->ctrl.admin_q, nvme_req_op(&cmd),
+					 BLK_MQ_REQ_NOWAIT);
+	if (IS_ERR(abort_req)) {
+		atomic_inc(&dev->ctrl.abort_limit);
+		return BLK_EH_RESET_TIMER;
+	}
+	nvme_init_request(abort_req, &cmd);
+
+	abort_req->end_io = abort_endio;
+	abort_req->end_io_data = NULL;
+	blk_execute_rq_nowait(abort_req, false);
+
+	/*
+	 * The aborted req will be completed on receiving the abort req.
+	 * We enable the timer again. If hit twice, it'll cause a device reset,
+	 * as the device then is in a faulty state.
+	 */
+	return BLK_EH_RESET_TIMER;
+
+disable:
+	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING))
+		return BLK_EH_DONE;
+
+	nvme_dev_disable(dev, false);
+	if (nvme_try_sched_reset(&dev->ctrl))
+		nvme_unquiesce_io_queues(&dev->ctrl);
+	return BLK_EH_DONE;
+}
+
+static void nvme_free_queue(struct nvme_queue *nvmeq)
+{
+	dma_free_coherent(nvmeq->dev->dev, CQ_SIZE(nvmeq),
+				(void *)nvmeq->cqes, nvmeq->cq_dma_addr);
+	if (!nvmeq->sq_cmds)
+		return;
+
+	if (test_and_clear_bit(NVMEQ_SQ_CMB, &nvmeq->flags)) {
+		pci_free_p2pmem(to_pci_dev(nvmeq->dev->dev),
+				nvmeq->sq_cmds, SQ_SIZE(nvmeq));
+	} else {
+		dma_free_coherent(nvmeq->dev->dev, SQ_SIZE(nvmeq),
+				nvmeq->sq_cmds, nvmeq->sq_dma_addr);
+	}
+}
+
+static void nvme_free_queues(struct nvme_dev *dev, int lowest)
+{
+	int i;
+
+	for (i = dev->ctrl.queue_count - 1; i >= lowest; i--) {
+		dev->ctrl.queue_count--;
+		nvme_free_queue(&dev->queues[i]);
+	}
+}
+
+static void nvme_suspend_queue(struct nvme_dev *dev, unsigned int qid)
+{
+	struct nvme_queue *nvmeq = &dev->queues[qid];
+
+	if (!test_and_clear_bit(NVMEQ_ENABLED, &nvmeq->flags))
+		return;
+
+	/* ensure that nvme_queue_rq() sees NVMEQ_ENABLED cleared */
+	mb();
+
+	nvmeq->dev->online_queues--;
+	if (!nvmeq->qid && nvmeq->dev->ctrl.admin_q)
+		nvme_quiesce_admin_queue(&nvmeq->dev->ctrl);
+	if (!test_and_clear_bit(NVMEQ_POLLED, &nvmeq->flags))
+		pci_free_irq(to_pci_dev(dev->dev), nvmeq->cq_vector, nvmeq);
+}
+
+static void nvme_suspend_io_queues(struct nvme_dev *dev)
+{
+	int i;
+
+	for (i = dev->ctrl.queue_count - 1; i > 0; i--)
+		nvme_suspend_queue(dev, i);
+}
+
+/*
+ * Called only on a device that has been disabled and after all other threads
+ * that can check this device's completion queues have synced, except
+ * nvme_poll(). This is the last chance for the driver to see a natural
+ * completion before nvme_cancel_request() terminates all incomplete requests.
+ */
+static void nvme_reap_pending_cqes(struct nvme_dev *dev)
+{
+	int i;
+
+	for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+		spin_lock(&dev->queues[i].cq_poll_lock);
+		nvme_poll_cq(&dev->queues[i], NULL);
+		spin_unlock(&dev->queues[i].cq_poll_lock);
+	}
+}
+
+static int nvme_cmb_qdepth(struct nvme_dev *dev, int nr_io_queues,
+				int entry_size)
+{
+	int q_depth = dev->q_depth;
+	unsigned q_size_aligned = roundup(q_depth * entry_size,
+					  NVME_CTRL_PAGE_SIZE);
+
+	if (q_size_aligned * nr_io_queues > dev->cmb_size) {
+		u64 mem_per_q = div_u64(dev->cmb_size, nr_io_queues);
+
+		mem_per_q = round_down(mem_per_q, NVME_CTRL_PAGE_SIZE);
+		q_depth = div_u64(mem_per_q, entry_size);
+
+		/*
+		 * Ensure the reduced q_depth is above some threshold where it
+		 * would be better to map queues in system memory with the
+		 * original depth
+		 */
+		if (q_depth < 64)
+			return -ENOMEM;
+	}
+
+	return q_depth;
+}
+
+static int nvme_alloc_sq_cmds(struct nvme_dev *dev, struct nvme_queue *nvmeq,
+				int qid)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	if (qid && dev->cmb_use_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {
+		nvmeq->sq_cmds = pci_alloc_p2pmem(pdev, SQ_SIZE(nvmeq));
+		if (nvmeq->sq_cmds) {
+			nvmeq->sq_dma_addr = pci_p2pmem_virt_to_bus(pdev,
+							nvmeq->sq_cmds);
+			if (nvmeq->sq_dma_addr) {
+				set_bit(NVMEQ_SQ_CMB, &nvmeq->flags);
+				return 0;
+			}
+
+			pci_free_p2pmem(pdev, nvmeq->sq_cmds, SQ_SIZE(nvmeq));
+		}
+	}
+
+	nvmeq->sq_cmds = dma_alloc_coherent(dev->dev, SQ_SIZE(nvmeq),
+				&nvmeq->sq_dma_addr, GFP_KERNEL);
+	if (!nvmeq->sq_cmds)
+		return -ENOMEM;
+	return 0;
+}
+
+static int nvme_alloc_queue(struct nvme_dev *dev, int qid, int depth)
+{
+	struct nvme_queue *nvmeq = &dev->queues[qid];
+
+	if (dev->ctrl.queue_count > qid)
+		return 0;
+
+	nvmeq->sqes = qid ? dev->io_sqes : NVME_ADM_SQES;
+	nvmeq->q_depth = depth;
+	nvmeq->cqes = dma_alloc_coherent(dev->dev, CQ_SIZE(nvmeq),
+					 &nvmeq->cq_dma_addr, GFP_KERNEL);
+	if (!nvmeq->cqes)
+		goto free_nvmeq;
+
+	if (nvme_alloc_sq_cmds(dev, nvmeq, qid))
+		goto free_cqdma;
+
+	nvmeq->dev = dev;
+	spin_lock_init(&nvmeq->sq_lock);
+	spin_lock_init(&nvmeq->cq_poll_lock);
+	nvmeq->cq_head = 0;
+	nvmeq->cq_phase = 1;
+	nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
+	nvmeq->qid = qid;
+	dev->ctrl.queue_count++;
+
+	return 0;
+
+ free_cqdma:
+	dma_free_coherent(dev->dev, CQ_SIZE(nvmeq), (void *)nvmeq->cqes,
+			  nvmeq->cq_dma_addr);
+ free_nvmeq:
+	return -ENOMEM;
+}
+
+static int queue_request_irq(struct nvme_queue *nvmeq)
+{
+	struct pci_dev *pdev = to_pci_dev(nvmeq->dev->dev);
+	int nr = nvmeq->dev->ctrl.instance;
+
+	if (use_threaded_interrupts) {
+		return pci_request_irq(pdev, nvmeq->cq_vector, nvme_irq_check,
+				nvme_irq, nvmeq, "nvme%dq%d", nr, nvmeq->qid);
+	} else {
+		return pci_request_irq(pdev, nvmeq->cq_vector, nvme_irq,
+				NULL, nvmeq, "nvme%dq%d", nr, nvmeq->qid);
+	}
+}
+
+static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
+{
+	struct nvme_dev *dev = nvmeq->dev;
+
+	nvmeq->sq_tail = 0;
+	nvmeq->last_sq_tail = 0;
+	nvmeq->cq_head = 0;
+	nvmeq->cq_phase = 1;
+	nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
+	memset((void *)nvmeq->cqes, 0, CQ_SIZE(nvmeq));
+	nvme_dbbuf_init(dev, nvmeq, qid);
+	dev->online_queues++;
+	wmb(); /* ensure the first interrupt sees the initialization */
+}
+
+/*
+ * Try getting shutdown_lock while setting up IO queues.
+ */
+static int nvme_setup_io_queues_trylock(struct nvme_dev *dev)
+{
+	/*
+	 * Give up if the lock is being held by nvme_dev_disable.
+	 */
+	if (!mutex_trylock(&dev->shutdown_lock))
+		return -ENODEV;
+
+	/*
+	 * Controller is in wrong state, fail early.
+	 */
+	if (nvme_ctrl_state(&dev->ctrl) != NVME_CTRL_CONNECTING) {
+		mutex_unlock(&dev->shutdown_lock);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
+{
+	struct nvme_dev *dev = nvmeq->dev;
+	int result;
+	u16 vector = 0;
+
+	clear_bit(NVMEQ_DELETE_ERROR, &nvmeq->flags);
+
+	/*
+	 * A queue's vector matches the queue identifier unless the controller
+	 * has only one vector available.
+	 */
+	if (!polled)
+		vector = dev->num_vecs == 1 ? 0 : qid;
+	else
+		set_bit(NVMEQ_POLLED, &nvmeq->flags);
+
+	result = adapter_alloc_cq(dev, qid, nvmeq, vector);
+	if (result)
+		return result;
+
+	result = adapter_alloc_sq(dev, qid, nvmeq);
+	if (result < 0)
+		return result;
+	if (result)
+		goto release_cq;
+
+	nvmeq->cq_vector = vector;
+
+	result = nvme_setup_io_queues_trylock(dev);
+	if (result)
+		return result;
+	nvme_init_queue(nvmeq, qid);
+	if (!polled) {
+		result = queue_request_irq(nvmeq);
+		if (result < 0)
+			goto release_sq;
+	}
+
+	set_bit(NVMEQ_ENABLED, &nvmeq->flags);
+	mutex_unlock(&dev->shutdown_lock);
+	return result;
+
+release_sq:
+	dev->online_queues--;
+	mutex_unlock(&dev->shutdown_lock);
+	adapter_delete_sq(dev, qid);
+release_cq:
+	adapter_delete_cq(dev, qid);
+	return result;
+}
+
+static const struct blk_mq_ops nvme_mq_admin_ops = {
+	.queue_rq	= nvme_queue_rq,
+	.complete	= nvme_pci_complete_rq,
+	.init_hctx	= nvme_admin_init_hctx,
+	.init_request	= nvme_pci_init_request,
+	.timeout	= nvme_timeout,
+};
+
+static const struct blk_mq_ops nvme_mq_ops = {
+	.queue_rq	= nvme_queue_rq,
+	.queue_rqs	= nvme_queue_rqs,
+	.complete	= nvme_pci_complete_rq,
+	.commit_rqs	= nvme_commit_rqs,
+	.init_hctx	= nvme_init_hctx,
+	.init_request	= nvme_pci_init_request,
+	.map_queues	= nvme_pci_map_queues,
+	.timeout	= nvme_timeout,
+	.poll		= nvme_poll,
+};
+
+static void nvme_dev_remove_admin(struct nvme_dev *dev)
+{
+	if (dev->ctrl.admin_q && !blk_queue_dying(dev->ctrl.admin_q)) {
+		/*
+		 * If the controller was reset during removal, it's possible
+		 * user requests may be waiting on a stopped queue. Start the
+		 * queue to flush these to completion.
+		 */
+		nvme_unquiesce_admin_queue(&dev->ctrl);
+		nvme_remove_admin_tag_set(&dev->ctrl);
+	}
+}
+
+static unsigned long db_bar_size(struct nvme_dev *dev, unsigned nr_io_queues)
+{
+	return NVME_REG_DBS + ((nr_io_queues + 1) * 8 * dev->db_stride);
+}
+
+static int nvme_remap_bar(struct nvme_dev *dev, unsigned long size)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	if (size <= dev->bar_mapped_size)
+		return 0;
+	if (size > pci_resource_len(pdev, 0))
+		return -ENOMEM;
+	if (dev->bar)
+		iounmap(dev->bar);
+	dev->bar = ioremap(pci_resource_start(pdev, 0), size);
+	if (!dev->bar) {
+		dev->bar_mapped_size = 0;
+		return -ENOMEM;
+	}
+	dev->bar_mapped_size = size;
+	dev->dbs = dev->bar + NVME_REG_DBS;
+
+	return 0;
+}
+
+static int nvme_pci_configure_admin_queue(struct nvme_dev *dev)
+{
+	int result;
+	u32 aqa;
+	struct nvme_queue *nvmeq;
+
+	result = nvme_remap_bar(dev, db_bar_size(dev, 0));
+	if (result < 0)
+		return result;
+
+	dev->subsystem = readl(dev->bar + NVME_REG_VS) >= NVME_VS(1, 1, 0) ?
+				NVME_CAP_NSSRC(dev->ctrl.cap) : 0;
+
+	if (dev->subsystem &&
+	    (readl(dev->bar + NVME_REG_CSTS) & NVME_CSTS_NSSRO))
+		writel(NVME_CSTS_NSSRO, dev->bar + NVME_REG_CSTS);
+
+	/*
+	 * If the device has been passed off to us in an enabled state, just
+	 * clear the enabled bit.  The spec says we should set the 'shutdown
+	 * notification bits', but doing so may cause the device to complete
+	 * commands to the admin queue ... and we don't know what memory that
+	 * might be pointing at!
+	 */
+	result = nvme_disable_ctrl(&dev->ctrl, false);
+	if (result < 0)
+		return result;
+
+	result = nvme_alloc_queue(dev, 0, NVME_AQ_DEPTH);
+	if (result)
+		return result;
+
+	dev->ctrl.numa_node = dev_to_node(dev->dev);
+
+	nvmeq = &dev->queues[0];
+	aqa = nvmeq->q_depth - 1;
+	aqa |= aqa << 16;
+
+	writel(aqa, dev->bar + NVME_REG_AQA);
+	lo_hi_writeq(nvmeq->sq_dma_addr, dev->bar + NVME_REG_ASQ);
+	lo_hi_writeq(nvmeq->cq_dma_addr, dev->bar + NVME_REG_ACQ);
+
+	result = nvme_enable_ctrl(&dev->ctrl);
+	if (result)
+		return result;
+
+	nvmeq->cq_vector = 0;
+	nvme_init_queue(nvmeq, 0);
+	result = queue_request_irq(nvmeq);
+	if (result) {
+		dev->online_queues--;
+		return result;
+	}
+
+	set_bit(NVMEQ_ENABLED, &nvmeq->flags);
+	return result;
+}
+
+static int nvme_create_io_queues(struct nvme_dev *dev)
+{
+	unsigned i, max, rw_queues;
+	int ret = 0;
+
+	for (i = dev->ctrl.queue_count; i <= dev->max_qid; i++) {
+		if (nvme_alloc_queue(dev, i, dev->q_depth)) {
+			ret = -ENOMEM;
+			break;
+		}
+	}
+
+	max = min(dev->max_qid, dev->ctrl.queue_count - 1);
+	if (max != 1 && dev->io_queues[HCTX_TYPE_POLL]) {
+		rw_queues = dev->io_queues[HCTX_TYPE_DEFAULT] +
+				dev->io_queues[HCTX_TYPE_READ];
+	} else {
+		rw_queues = max;
+	}
+
+	for (i = dev->online_queues; i <= max; i++) {
+		bool polled = i > rw_queues;
+
+		ret = nvme_create_queue(&dev->queues[i], i, polled);
+		if (ret)
+			break;
+	}
+
+	/*
+	 * Ignore failing Create SQ/CQ commands, we can continue with less
+	 * than the desired amount of queues, and even a controller without
+	 * I/O queues can still be used to issue admin commands.  This might
+	 * be useful to upgrade a buggy firmware for example.
+	 */
+	return ret >= 0 ? 0 : ret;
+}
+
+static u64 nvme_cmb_size_unit(struct nvme_dev *dev)
+{
+	u8 szu = (dev->cmbsz >> NVME_CMBSZ_SZU_SHIFT) & NVME_CMBSZ_SZU_MASK;
+
+	return 1ULL << (12 + 4 * szu);
+}
+
+static u32 nvme_cmb_size(struct nvme_dev *dev)
+{
+	return (dev->cmbsz >> NVME_CMBSZ_SZ_SHIFT) & NVME_CMBSZ_SZ_MASK;
+}
+
+static void nvme_map_cmb(struct nvme_dev *dev)
+{
+	u64 size, offset;
+	resource_size_t bar_size;
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	int bar;
+
+	if (dev->cmb_size)
+		return;
+
+	if (NVME_CAP_CMBS(dev->ctrl.cap))
+		writel(NVME_CMBMSC_CRE, dev->bar + NVME_REG_CMBMSC);
+
+	dev->cmbsz = readl(dev->bar + NVME_REG_CMBSZ);
+	if (!dev->cmbsz)
+		return;
+	dev->cmbloc = readl(dev->bar + NVME_REG_CMBLOC);
+
+	size = nvme_cmb_size_unit(dev) * nvme_cmb_size(dev);
+	offset = nvme_cmb_size_unit(dev) * NVME_CMB_OFST(dev->cmbloc);
+	bar = NVME_CMB_BIR(dev->cmbloc);
+	bar_size = pci_resource_len(pdev, bar);
+
+	if (offset > bar_size)
+		return;
+
+	/*
+	 * Tell the controller about the host side address mapping the CMB,
+	 * and enable CMB decoding for the NVMe 1.4+ scheme:
+	 */
+	if (NVME_CAP_CMBS(dev->ctrl.cap)) {
+		hi_lo_writeq(NVME_CMBMSC_CRE | NVME_CMBMSC_CMSE |
+			     (pci_bus_address(pdev, bar) + offset),
+			     dev->bar + NVME_REG_CMBMSC);
+	}
+
+	/*
+	 * Controllers may support a CMB size larger than their BAR,
+	 * for example, due to being behind a bridge. Reduce the CMB to
+	 * the reported size of the BAR
+	 */
+	if (size > bar_size - offset)
+		size = bar_size - offset;
+
+	if (pci_p2pdma_add_resource(pdev, bar, size, offset)) {
+		dev_warn(dev->ctrl.device,
+			 "failed to register the CMB\n");
+		return;
+	}
+
+	dev->cmb_size = size;
+	dev->cmb_use_sqes = use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS);
+
+	if ((dev->cmbsz & (NVME_CMBSZ_WDS | NVME_CMBSZ_RDS)) ==
+			(NVME_CMBSZ_WDS | NVME_CMBSZ_RDS))
+		pci_p2pmem_publish(pdev, true);
+
+	nvme_update_attrs(dev);
+}
+
+static int nvme_set_host_mem(struct nvme_dev *dev, u32 bits)
+{
+	u32 host_mem_size = dev->host_mem_size >> NVME_CTRL_PAGE_SHIFT;
+	u64 dma_addr = dev->host_mem_descs_dma;
+	struct nvme_command c = { };
+	int ret;
+
+	c.features.opcode	= nvme_admin_set_features;
+	c.features.fid		= cpu_to_le32(NVME_FEAT_HOST_MEM_BUF);
+	c.features.dword11	= cpu_to_le32(bits);
+	c.features.dword12	= cpu_to_le32(host_mem_size);
+	c.features.dword13	= cpu_to_le32(lower_32_bits(dma_addr));
+	c.features.dword14	= cpu_to_le32(upper_32_bits(dma_addr));
+	c.features.dword15	= cpu_to_le32(dev->nr_host_mem_descs);
+
+	ret = nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0);
+	if (ret) {
+		dev_warn(dev->ctrl.device,
+			 "failed to set host mem (err %d, flags %#x).\n",
+			 ret, bits);
+	} else
+		dev->hmb = bits & NVME_HOST_MEM_ENABLE;
+
+	return ret;
+}
+
+static void nvme_free_host_mem(struct nvme_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->nr_host_mem_descs; i++) {
+		struct nvme_host_mem_buf_desc *desc = &dev->host_mem_descs[i];
+		size_t size = le32_to_cpu(desc->size) * NVME_CTRL_PAGE_SIZE;
+
+		dma_free_attrs(dev->dev, size, dev->host_mem_desc_bufs[i],
+			       le64_to_cpu(desc->addr),
+			       DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_NO_WARN);
+	}
+
+	kfree(dev->host_mem_desc_bufs);
+	dev->host_mem_desc_bufs = NULL;
+	dma_free_coherent(dev->dev,
+			dev->nr_host_mem_descs * sizeof(*dev->host_mem_descs),
+			dev->host_mem_descs, dev->host_mem_descs_dma);
+	dev->host_mem_descs = NULL;
+	dev->nr_host_mem_descs = 0;
+}
+
+static int __nvme_alloc_host_mem(struct nvme_dev *dev, u64 preferred,
+		u32 chunk_size)
+{
+	struct nvme_host_mem_buf_desc *descs;
+	u32 max_entries, len;
+	dma_addr_t descs_dma;
+	int i = 0;
+	void **bufs;
+	u64 size, tmp;
+
+	tmp = (preferred + chunk_size - 1);
+	do_div(tmp, chunk_size);
+	max_entries = tmp;
+
+	if (dev->ctrl.hmmaxd && dev->ctrl.hmmaxd < max_entries)
+		max_entries = dev->ctrl.hmmaxd;
+
+	descs = dma_alloc_coherent(dev->dev, max_entries * sizeof(*descs),
+				   &descs_dma, GFP_KERNEL);
+	if (!descs)
+		goto out;
+
+	bufs = kcalloc(max_entries, sizeof(*bufs), GFP_KERNEL);
+	if (!bufs)
+		goto out_free_descs;
+
+	for (size = 0; size < preferred && i < max_entries; size += len) {
+		dma_addr_t dma_addr;
+
+		len = min_t(u64, chunk_size, preferred - size);
+		bufs[i] = dma_alloc_attrs(dev->dev, len, &dma_addr, GFP_KERNEL,
+				DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_NO_WARN);
+		if (!bufs[i])
+			break;
+
+		descs[i].addr = cpu_to_le64(dma_addr);
+		descs[i].size = cpu_to_le32(len / NVME_CTRL_PAGE_SIZE);
+		i++;
+	}
+
+	if (!size)
+		goto out_free_bufs;
+
+	dev->nr_host_mem_descs = i;
+	dev->host_mem_size = size;
+	dev->host_mem_descs = descs;
+	dev->host_mem_descs_dma = descs_dma;
+	dev->host_mem_desc_bufs = bufs;
+	return 0;
+
+out_free_bufs:
+	while (--i >= 0) {
+		size_t size = le32_to_cpu(descs[i].size) * NVME_CTRL_PAGE_SIZE;
+
+		dma_free_attrs(dev->dev, size, bufs[i],
+			       le64_to_cpu(descs[i].addr),
+			       DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_NO_WARN);
+	}
+
+	kfree(bufs);
+out_free_descs:
+	dma_free_coherent(dev->dev, max_entries * sizeof(*descs), descs,
+			descs_dma);
+out:
+	dev->host_mem_descs = NULL;
+	return -ENOMEM;
+}
+
+static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
+{
+	u64 min_chunk = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
+	u64 hmminds = max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
+	u64 chunk_size;
+
+	/* start big and work our way down */
+	for (chunk_size = min_chunk; chunk_size >= hmminds; chunk_size /= 2) {
+		if (!__nvme_alloc_host_mem(dev, preferred, chunk_size)) {
+			if (!min || dev->host_mem_size >= min)
+				return 0;
+			nvme_free_host_mem(dev);
+		}
+	}
+
+	return -ENOMEM;
+}
+
+static int nvme_setup_host_mem(struct nvme_dev *dev)
+{
+	u64 max = (u64)max_host_mem_size_mb * SZ_1M;
+	u64 preferred = (u64)dev->ctrl.hmpre * 4096;
+	u64 min = (u64)dev->ctrl.hmmin * 4096;
+	u32 enable_bits = NVME_HOST_MEM_ENABLE;
+	int ret;
+
+	if (!dev->ctrl.hmpre)
+		return 0;
+
+	preferred = min(preferred, max);
+	if (min > max) {
+		dev_warn(dev->ctrl.device,
+			"min host memory (%lld MiB) above limit (%d MiB).\n",
+			min >> ilog2(SZ_1M), max_host_mem_size_mb);
+		nvme_free_host_mem(dev);
+		return 0;
+	}
+
+	/*
+	 * If we already have a buffer allocated check if we can reuse it.
+	 */
+	if (dev->host_mem_descs) {
+		if (dev->host_mem_size >= min)
+			enable_bits |= NVME_HOST_MEM_RETURN;
+		else
+			nvme_free_host_mem(dev);
+	}
+
+	if (!dev->host_mem_descs) {
+		if (nvme_alloc_host_mem(dev, min, preferred)) {
+			dev_warn(dev->ctrl.device,
+				"failed to allocate host memory buffer.\n");
+			return 0; /* controller must work without HMB */
+		}
+
+		dev_info(dev->ctrl.device,
+			"allocated %lld MiB host memory buffer.\n",
+			dev->host_mem_size >> ilog2(SZ_1M));
+	}
+
+	ret = nvme_set_host_mem(dev, enable_bits);
+	if (ret)
+		nvme_free_host_mem(dev);
+	return ret;
+}
+
+static ssize_t cmb_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "cmbloc : x%08x\ncmbsz  : x%08x\n",
+		       ndev->cmbloc, ndev->cmbsz);
+}
+static DEVICE_ATTR_RO(cmb);
+
+static ssize_t cmbloc_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "%u\n", ndev->cmbloc);
+}
+static DEVICE_ATTR_RO(cmbloc);
+
+static ssize_t cmbsz_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "%u\n", ndev->cmbsz);
+}
+static DEVICE_ATTR_RO(cmbsz);
+
+static ssize_t hmb_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "%d\n", ndev->hmb);
+}
+
+static ssize_t hmb_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+	bool new;
+	int ret;
+
+	if (kstrtobool(buf, &new) < 0)
+		return -EINVAL;
+
+	if (new == ndev->hmb)
+		return count;
+
+	if (new) {
+		ret = nvme_setup_host_mem(ndev);
+	} else {
+		ret = nvme_set_host_mem(ndev, 0);
+		if (!ret)
+			nvme_free_host_mem(ndev);
+	}
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_RW(hmb);
+
+static umode_t nvme_pci_attrs_are_visible(struct kobject *kobj,
+		struct attribute *a, int n)
+{
+	struct nvme_ctrl *ctrl =
+		dev_get_drvdata(container_of(kobj, struct device, kobj));
+	struct nvme_dev *dev = to_nvme_dev(ctrl);
+
+	if (a == &dev_attr_cmb.attr ||
+	    a == &dev_attr_cmbloc.attr ||
+	    a == &dev_attr_cmbsz.attr) {
+	    	if (!dev->cmbsz)
+			return 0;
+	}
+	if (a == &dev_attr_hmb.attr && !ctrl->hmpre)
+		return 0;
+
+	return a->mode;
+}
+
+static struct attribute *nvme_pci_attrs[] = {
+	&dev_attr_cmb.attr,
+	&dev_attr_cmbloc.attr,
+	&dev_attr_cmbsz.attr,
+	&dev_attr_hmb.attr,
+	NULL,
+};
+
+static const struct attribute_group nvme_pci_dev_attrs_group = {
+	.attrs		= nvme_pci_attrs,
+	.is_visible	= nvme_pci_attrs_are_visible,
+};
+
+static const struct attribute_group *nvme_pci_dev_attr_groups[] = {
+	&nvme_dev_attrs_group,
+	&nvme_pci_dev_attrs_group,
+	NULL,
+};
+
+static void nvme_update_attrs(struct nvme_dev *dev)
+{
+	sysfs_update_group(&dev->ctrl.device->kobj, &nvme_pci_dev_attrs_group);
+}
+
+/*
+ * nirqs is the number of interrupts available for write and read
+ * queues. The core already reserved an interrupt for the admin queue.
+ */
+static void nvme_calc_irq_sets(struct irq_affinity *affd, unsigned int nrirqs)
+{
+	struct nvme_dev *dev = affd->priv;
+	unsigned int nr_read_queues, nr_write_queues = dev->nr_write_queues;
+
+	/*
+	 * If there is no interrupt available for queues, ensure that
+	 * the default queue is set to 1. The affinity set size is
+	 * also set to one, but the irq core ignores it for this case.
+	 *
+	 * If only one interrupt is available or 'write_queue' == 0, combine
+	 * write and read queues.
+	 *
+	 * If 'write_queues' > 0, ensure it leaves room for at least one read
+	 * queue.
+	 */
+	if (!nrirqs) {
+		nrirqs = 1;
+		nr_read_queues = 0;
+	} else if (nrirqs == 1 || !nr_write_queues) {
+		nr_read_queues = 0;
+	} else if (nr_write_queues >= nrirqs) {
+		nr_read_queues = 1;
+	} else {
+		nr_read_queues = nrirqs - nr_write_queues;
+	}
+
+	dev->io_queues[HCTX_TYPE_DEFAULT] = nrirqs - nr_read_queues;
+	affd->set_size[HCTX_TYPE_DEFAULT] = nrirqs - nr_read_queues;
+	dev->io_queues[HCTX_TYPE_READ] = nr_read_queues;
+	affd->set_size[HCTX_TYPE_READ] = nr_read_queues;
+	affd->nr_sets = nr_read_queues ? 2 : 1;
+}
+
+static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	struct irq_affinity affd = {
+		.pre_vectors	= 1,
+		.calc_sets	= nvme_calc_irq_sets,
+		.priv		= dev,
+	};
+	unsigned int irq_queues, poll_queues;
+
+	/*
+	 * Poll queues don't need interrupts, but we need at least one I/O queue
+	 * left over for non-polled I/O.
+	 */
+	poll_queues = min(dev->nr_poll_queues, nr_io_queues - 1);
+	dev->io_queues[HCTX_TYPE_POLL] = poll_queues;
+
+	/*
+	 * Initialize for the single interrupt case, will be updated in
+	 * nvme_calc_irq_sets().
+	 */
+	dev->io_queues[HCTX_TYPE_DEFAULT] = 1;
+	dev->io_queues[HCTX_TYPE_READ] = 0;
+
+	/*
+	 * We need interrupts for the admin queue and each non-polled I/O queue,
+	 * but some Apple controllers require all queues to use the first
+	 * vector.
+	 */
+	irq_queues = 1;
+	if (!(dev->ctrl.quirks & NVME_QUIRK_SINGLE_VECTOR))
+		irq_queues += (nr_io_queues - poll_queues);
+	return pci_alloc_irq_vectors_affinity(pdev, 1, irq_queues,
+			      PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY, &affd);
+}
+
+static unsigned int nvme_max_io_queues(struct nvme_dev *dev)
+{
+	/*
+	 * If tags are shared with admin queue (Apple bug), then
+	 * make sure we only use one IO queue.
+	 */
+	if (dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS)
+		return 1;
+	return num_possible_cpus() + dev->nr_write_queues + dev->nr_poll_queues;
+}
+
+static int nvme_setup_io_queues(struct nvme_dev *dev)
+{
+	struct nvme_queue *adminq = &dev->queues[0];
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	unsigned int nr_io_queues;
+	unsigned long size;
+	int result;
+
+	/*
+	 * Sample the module parameters once at reset time so that we have
+	 * stable values to work with.
+	 */
+	dev->nr_write_queues = write_queues;
+	dev->nr_poll_queues = poll_queues;
+
+	nr_io_queues = dev->nr_allocated_queues - 1;
+	result = nvme_set_queue_count(&dev->ctrl, &nr_io_queues);
+	if (result < 0)
+		return result;
+
+	if (nr_io_queues == 0)
+		return 0;
+
+	/*
+	 * Free IRQ resources as soon as NVMEQ_ENABLED bit transitions
+	 * from set to unset. If there is a window to it is truely freed,
+	 * pci_free_irq_vectors() jumping into this window will crash.
+	 * And take lock to avoid racing with pci_free_irq_vectors() in
+	 * nvme_dev_disable() path.
+	 */
+	result = nvme_setup_io_queues_trylock(dev);
+	if (result)
+		return result;
+	if (test_and_clear_bit(NVMEQ_ENABLED, &adminq->flags))
+		pci_free_irq(pdev, 0, adminq);
+
+	if (dev->cmb_use_sqes) {
+		result = nvme_cmb_qdepth(dev, nr_io_queues,
+				sizeof(struct nvme_command));
+		if (result > 0) {
+			dev->q_depth = result;
+			dev->ctrl.sqsize = result - 1;
+		} else {
+			dev->cmb_use_sqes = false;
+		}
+	}
+
+	do {
+		size = db_bar_size(dev, nr_io_queues);
+		result = nvme_remap_bar(dev, size);
+		if (!result)
+			break;
+		if (!--nr_io_queues) {
+			result = -ENOMEM;
+			goto out_unlock;
+		}
+	} while (1);
+	adminq->q_db = dev->dbs;
+
+ retry:
+	/* Deregister the admin queue's interrupt */
+	if (test_and_clear_bit(NVMEQ_ENABLED, &adminq->flags))
+		pci_free_irq(pdev, 0, adminq);
+
+	/*
+	 * If we enable msix early due to not intx, disable it again before
+	 * setting up the full range we need.
+	 */
+	pci_free_irq_vectors(pdev);
+
+	result = nvme_setup_irqs(dev, nr_io_queues);
+	if (result <= 0) {
+		result = -EIO;
+		goto out_unlock;
+	}
+
+	dev->num_vecs = result;
+	result = max(result - 1, 1);
+	dev->max_qid = result + dev->io_queues[HCTX_TYPE_POLL];
+
+	/*
+	 * Should investigate if there's a performance win from allocating
+	 * more queues than interrupt vectors; it might allow the submission
+	 * path to scale better, even if the receive path is limited by the
+	 * number of interrupts.
+	 */
+	result = queue_request_irq(adminq);
+	if (result)
+		goto out_unlock;
+	set_bit(NVMEQ_ENABLED, &adminq->flags);
+	mutex_unlock(&dev->shutdown_lock);
+
+	result = nvme_create_io_queues(dev);
+	if (result || dev->online_queues < 2)
+		return result;
+
+	if (dev->online_queues - 1 < dev->max_qid) {
+		nr_io_queues = dev->online_queues - 1;
+		nvme_delete_io_queues(dev);
+		result = nvme_setup_io_queues_trylock(dev);
+		if (result)
+			return result;
+		nvme_suspend_io_queues(dev);
+		goto retry;
+	}
+	dev_info(dev->ctrl.device, "%d/%d/%d default/read/poll queues\n",
+					dev->io_queues[HCTX_TYPE_DEFAULT],
+					dev->io_queues[HCTX_TYPE_READ],
+					dev->io_queues[HCTX_TYPE_POLL]);
+	return 0;
+out_unlock:
+	mutex_unlock(&dev->shutdown_lock);
+	return result;
+}
+
+static enum rq_end_io_ret nvme_del_queue_end(struct request *req,
+					     blk_status_t error)
+{
+	struct nvme_queue *nvmeq = req->end_io_data;
+
+	blk_mq_free_request(req);
+	complete(&nvmeq->delete_done);
+	return RQ_END_IO_NONE;
+}
+
+static enum rq_end_io_ret nvme_del_cq_end(struct request *req,
+					  blk_status_t error)
+{
+	struct nvme_queue *nvmeq = req->end_io_data;
+
+	if (error)
+		set_bit(NVMEQ_DELETE_ERROR, &nvmeq->flags);
+
+	return nvme_del_queue_end(req, error);
+}
+
+static int nvme_delete_queue(struct nvme_queue *nvmeq, u8 opcode)
+{
+	struct request_queue *q = nvmeq->dev->ctrl.admin_q;
+	struct request *req;
+	struct nvme_command cmd = { };
+
+	cmd.delete_queue.opcode = opcode;
+	cmd.delete_queue.qid = cpu_to_le16(nvmeq->qid);
+
+	req = blk_mq_alloc_request(q, nvme_req_op(&cmd), BLK_MQ_REQ_NOWAIT);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	nvme_init_request(req, &cmd);
+
+	if (opcode == nvme_admin_delete_cq)
+		req->end_io = nvme_del_cq_end;
+	else
+		req->end_io = nvme_del_queue_end;
+	req->end_io_data = nvmeq;
+
+	init_completion(&nvmeq->delete_done);
+	blk_execute_rq_nowait(req, false);
+	return 0;
+}
+
+static bool __nvme_delete_io_queues(struct nvme_dev *dev, u8 opcode)
+{
+	int nr_queues = dev->online_queues - 1, sent = 0;
+	unsigned long timeout;
+
+ retry:
+	timeout = NVME_ADMIN_TIMEOUT;
+	while (nr_queues > 0) {
+		if (nvme_delete_queue(&dev->queues[nr_queues], opcode))
+			break;
+		nr_queues--;
+		sent++;
+	}
+	while (sent) {
+		struct nvme_queue *nvmeq = &dev->queues[nr_queues + sent];
+
+		timeout = wait_for_completion_io_timeout(&nvmeq->delete_done,
+				timeout);
+		if (timeout == 0)
+			return false;
+
+		sent--;
+		if (nr_queues)
+			goto retry;
+	}
+	return true;
+}
+
+static void nvme_delete_io_queues(struct nvme_dev *dev)
+{
+	if (__nvme_delete_io_queues(dev, nvme_admin_delete_sq))
+		__nvme_delete_io_queues(dev, nvme_admin_delete_cq);
+}
+
+static unsigned int nvme_pci_nr_maps(struct nvme_dev *dev)
+{
+	if (dev->io_queues[HCTX_TYPE_POLL])
+		return 3;
+	if (dev->io_queues[HCTX_TYPE_READ])
+		return 2;
+	return 1;
+}
+
+static void nvme_pci_update_nr_queues(struct nvme_dev *dev)
+{
+	blk_mq_update_nr_hw_queues(&dev->tagset, dev->online_queues - 1);
+	/* free previously allocated queues that are no longer usable */
+	nvme_free_queues(dev, dev->online_queues);
+}
+
+static int nvme_pci_enable(struct nvme_dev *dev)
+{
+	int result = -ENOMEM;
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	if (pci_enable_device_mem(pdev))
+		return result;
+
+	pci_set_master(pdev);
+
+	if (readl(dev->bar + NVME_REG_CSTS) == -1) {
+		result = -ENODEV;
+		goto disable;
+	}
+
+	/*
+	 * Some devices and/or platforms don't advertise or work with INTx
+	 * interrupts. Pre-enable a single MSIX or MSI vec for setup. We'll
+	 * adjust this later.
+	 */
+	result = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
+	if (result < 0)
+		goto disable;
+
+	dev->ctrl.cap = lo_hi_readq(dev->bar + NVME_REG_CAP);
+
+	dev->q_depth = min_t(u32, NVME_CAP_MQES(dev->ctrl.cap) + 1,
+				io_queue_depth);
+	dev->db_stride = 1 << NVME_CAP_STRIDE(dev->ctrl.cap);
+	dev->dbs = dev->bar + 4096;
+
+	/*
+	 * Some Apple controllers require a non-standard SQE size.
+	 * Interestingly they also seem to ignore the CC:IOSQES register
+	 * so we don't bother updating it here.
+	 */
+	if (dev->ctrl.quirks & NVME_QUIRK_128_BYTES_SQES)
+		dev->io_sqes = 7;
+	else
+		dev->io_sqes = NVME_NVM_IOSQES;
+
+	/*
+	 * Temporary fix for the Apple controller found in the MacBook8,1 and
+	 * some MacBook7,1 to avoid controller resets and data loss.
+	 */
+	if (pdev->vendor == PCI_VENDOR_ID_APPLE && pdev->device == 0x2001) {
+		dev->q_depth = 2;
+		dev_warn(dev->ctrl.device, "detected Apple NVMe controller, "
+			"set queue depth=%u to work around controller resets\n",
+			dev->q_depth);
+	} else if (pdev->vendor == PCI_VENDOR_ID_SAMSUNG &&
+		   (pdev->device == 0xa821 || pdev->device == 0xa822) &&
+		   NVME_CAP_MQES(dev->ctrl.cap) == 0) {
+		dev->q_depth = 64;
+		dev_err(dev->ctrl.device, "detected PM1725 NVMe controller, "
+                        "set queue depth=%u\n", dev->q_depth);
+	}
+
+	/*
+	 * Controllers with the shared tags quirk need the IO queue to be
+	 * big enough so that we get 32 tags for the admin queue
+	 */
+	if ((dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS) &&
+	    (dev->q_depth < (NVME_AQ_DEPTH + 2))) {
+		dev->q_depth = NVME_AQ_DEPTH + 2;
+		dev_warn(dev->ctrl.device, "IO queue depth clamped to %d\n",
+			 dev->q_depth);
+	}
+	dev->ctrl.sqsize = dev->q_depth - 1; /* 0's based queue depth */
+
+	nvme_map_cmb(dev);
+
+	pci_save_state(pdev);
+
+	result = nvme_pci_configure_admin_queue(dev);
+	if (result)
+		goto free_irq;
+	return result;
+
+ free_irq:
+	pci_free_irq_vectors(pdev);
+ disable:
+	pci_disable_device(pdev);
+	return result;
+}
+
+static void nvme_dev_unmap(struct nvme_dev *dev)
+{
+	if (dev->bar)
+		iounmap(dev->bar);
+	pci_release_mem_regions(to_pci_dev(dev->dev));
+}
+
+static bool nvme_pci_ctrl_is_dead(struct nvme_dev *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	u32 csts;
+
+	if (!pci_is_enabled(pdev) || !pci_device_is_present(pdev))
+		return true;
+	if (pdev->error_state != pci_channel_io_normal)
+		return true;
+
+	csts = readl(dev->bar + NVME_REG_CSTS);
+	return (csts & NVME_CSTS_CFS) || !(csts & NVME_CSTS_RDY);
+}
+
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
+{
+	enum nvme_ctrl_state state = nvme_ctrl_state(&dev->ctrl);
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	bool dead;
+
+	mutex_lock(&dev->shutdown_lock);
+	dead = nvme_pci_ctrl_is_dead(dev);
+	if (state == NVME_CTRL_LIVE || state == NVME_CTRL_RESETTING) {
+		if (pci_is_enabled(pdev))
+			nvme_start_freeze(&dev->ctrl);
+		/*
+		 * Give the controller a chance to complete all entered requests
+		 * if doing a safe shutdown.
+		 */
+		if (!dead && shutdown)
+			nvme_wait_freeze_timeout(&dev->ctrl, NVME_IO_TIMEOUT);
+	}
+
+	nvme_quiesce_io_queues(&dev->ctrl);
+
+	if (!dead && dev->ctrl.queue_count > 0) {
+		nvme_delete_io_queues(dev);
+		nvme_disable_ctrl(&dev->ctrl, shutdown);
+		nvme_poll_irqdisable(&dev->queues[0]);
+	}
+	nvme_suspend_io_queues(dev);
+	nvme_suspend_queue(dev, 0);
+	pci_free_irq_vectors(pdev);
+	if (pci_is_enabled(pdev))
+		pci_disable_device(pdev);
+	nvme_reap_pending_cqes(dev);
+
+	nvme_cancel_tagset(&dev->ctrl);
+	nvme_cancel_admin_tagset(&dev->ctrl);
+
+	/*
+	 * The driver will not be starting up queues again if shutting down so
+	 * must flush all entered requests to their failed completion to avoid
+	 * deadlocking blk-mq hot-cpu notifier.
+	 */
+	if (shutdown) {
+		nvme_unquiesce_io_queues(&dev->ctrl);
+		if (dev->ctrl.admin_q && !blk_queue_dying(dev->ctrl.admin_q))
+			nvme_unquiesce_admin_queue(&dev->ctrl);
+	}
+	mutex_unlock(&dev->shutdown_lock);
+}
+
+static int nvme_disable_prepare_reset(struct nvme_dev *dev, bool shutdown)
+{
+	if (!nvme_wait_reset(&dev->ctrl))
+		return -EBUSY;
+	nvme_dev_disable(dev, shutdown);
+	return 0;
+}
+
+static int nvme_setup_prp_pools(struct nvme_dev *dev)
+{
+	dev->prp_page_pool = dma_pool_create("prp list page", dev->dev,
+						NVME_CTRL_PAGE_SIZE,
+						NVME_CTRL_PAGE_SIZE, 0);
+	if (!dev->prp_page_pool)
+		return -ENOMEM;
+
+	/* Optimisation for I/Os between 4k and 128k */
+	dev->prp_small_pool = dma_pool_create("prp list 256", dev->dev,
+						256, 256, 0);
+	if (!dev->prp_small_pool) {
+		dma_pool_destroy(dev->prp_page_pool);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void nvme_release_prp_pools(struct nvme_dev *dev)
+{
+	dma_pool_destroy(dev->prp_page_pool);
+	dma_pool_destroy(dev->prp_small_pool);
+}
+
+static int nvme_pci_alloc_iod_mempool(struct nvme_dev *dev)
+{
+	size_t alloc_size = sizeof(struct scatterlist) * NVME_MAX_SEGS;
+
+	dev->iod_mempool = mempool_create_node(1,
+			mempool_kmalloc, mempool_kfree,
+			(void *)alloc_size, GFP_KERNEL,
+			dev_to_node(dev->dev));
+	if (!dev->iod_mempool)
+		return -ENOMEM;
+	return 0;
+}
+
+static void nvme_free_tagset(struct nvme_dev *dev)
+{
+	if (dev->tagset.tags)
+		nvme_remove_io_tag_set(&dev->ctrl);
+	dev->ctrl.tagset = NULL;
+}
+
+/* pairs with nvme_pci_alloc_dev */
+static void nvme_pci_free_ctrl(struct nvme_ctrl *ctrl)
+{
+	struct nvme_dev *dev = to_nvme_dev(ctrl);
+
+	nvme_free_tagset(dev);
+	put_device(dev->dev);
+	kfree(dev->queues);
+	kfree(dev);
+}
+
+static void nvme_reset_work(struct work_struct *work)
+{
+	struct nvme_dev *dev =
+		container_of(work, struct nvme_dev, ctrl.reset_work);
+	bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
+	int result;
+
+	if (nvme_ctrl_state(&dev->ctrl) != NVME_CTRL_RESETTING) {
+		dev_warn(dev->ctrl.device, "ctrl state %d is not RESETTING\n",
+			 dev->ctrl.state);
+		result = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * If we're called to reset a live controller first shut it down before
+	 * moving on.
+	 */
+	if (dev->ctrl.ctrl_config & NVME_CC_ENABLE)
+		nvme_dev_disable(dev, false);
+	nvme_sync_queues(&dev->ctrl);
+
+	mutex_lock(&dev->shutdown_lock);
+	result = nvme_pci_enable(dev);
+	if (result)
+		goto out_unlock;
+	nvme_unquiesce_admin_queue(&dev->ctrl);
+	mutex_unlock(&dev->shutdown_lock);
+
+	/*
+	 * Introduce CONNECTING state from nvme-fc/rdma transports to mark the
+	 * initializing procedure here.
+	 */
+	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_CONNECTING)) {
+		dev_warn(dev->ctrl.device,
+			"failed to mark controller CONNECTING\n");
+		result = -EBUSY;
+		goto out;
+	}
+
+	result = nvme_init_ctrl_finish(&dev->ctrl, was_suspend);
+	if (result)
+		goto out;
+
+	nvme_dbbuf_dma_alloc(dev);
+
+	result = nvme_setup_host_mem(dev);
+	if (result < 0)
+		goto out;
+
+	result = nvme_setup_io_queues(dev);
+	if (result)
+		goto out;
+
+	/*
+	 * Freeze and update the number of I/O queues as thos might have
+	 * changed.  If there are no I/O queues left after this reset, keep the
+	 * controller around but remove all namespaces.
+	 */
+	if (dev->online_queues > 1) {
+		nvme_unquiesce_io_queues(&dev->ctrl);
+		nvme_wait_freeze(&dev->ctrl);
+		nvme_pci_update_nr_queues(dev);
+		nvme_dbbuf_set(dev);
+		nvme_unfreeze(&dev->ctrl);
+	} else {
+		dev_warn(dev->ctrl.device, "IO queues lost\n");
+		nvme_mark_namespaces_dead(&dev->ctrl);
+		nvme_unquiesce_io_queues(&dev->ctrl);
+		nvme_remove_namespaces(&dev->ctrl);
+		nvme_free_tagset(dev);
+	}
+
+	/*
+	 * If only admin queue live, keep it to do further investigation or
+	 * recovery.
+	 */
+	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_LIVE)) {
+		dev_warn(dev->ctrl.device,
+			"failed to mark controller live state\n");
+		result = -ENODEV;
+		goto out;
+	}
+
+	nvme_start_ctrl(&dev->ctrl);
+	return;
+
+ out_unlock:
+	mutex_unlock(&dev->shutdown_lock);
+ out:
+	/*
+	 * Set state to deleting now to avoid blocking nvme_wait_reset(), which
+	 * may be holding this pci_dev's device lock.
+	 */
+	dev_warn(dev->ctrl.device, "Disabling device after reset failure: %d\n",
+		 result);
+	nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
+	nvme_dev_disable(dev, true);
+	nvme_sync_queues(&dev->ctrl);
+	nvme_mark_namespaces_dead(&dev->ctrl);
+	nvme_unquiesce_io_queues(&dev->ctrl);
+	nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DEAD);
+}
+
+static int nvme_pci_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
+{
+	*val = readl(to_nvme_dev(ctrl)->bar + off);
+	return 0;
+}
+
+static int nvme_pci_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
+{
+	writel(val, to_nvme_dev(ctrl)->bar + off);
+	return 0;
+}
+
+static int nvme_pci_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val)
+{
+	*val = lo_hi_readq(to_nvme_dev(ctrl)->bar + off);
+	return 0;
+}
+
+static int nvme_pci_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
+{
+	struct pci_dev *pdev = to_pci_dev(to_nvme_dev(ctrl)->dev);
+
+	return snprintf(buf, size, "%s\n", dev_name(&pdev->dev));
+}
+
+static void nvme_pci_print_device_info(struct nvme_ctrl *ctrl)
+{
+	struct pci_dev *pdev = to_pci_dev(to_nvme_dev(ctrl)->dev);
+	struct nvme_subsystem *subsys = ctrl->subsys;
+
+	dev_err(ctrl->device,
+		"VID:DID %04x:%04x model:%.*s firmware:%.*s\n",
+		pdev->vendor, pdev->device,
+		nvme_strlen(subsys->model, sizeof(subsys->model)),
+		subsys->model, nvme_strlen(subsys->firmware_rev,
+					   sizeof(subsys->firmware_rev)),
+		subsys->firmware_rev);
+}
+
+static bool nvme_pci_supports_pci_p2pdma(struct nvme_ctrl *ctrl)
+{
+	struct nvme_dev *dev = to_nvme_dev(ctrl);
+
+	return dma_pci_p2pdma_supported(dev->dev);
+}
+
+static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
+	.name			= "pcie",
+	.module			= THIS_MODULE,
+	.flags			= NVME_F_METADATA_SUPPORTED,
+	.dev_attr_groups	= nvme_pci_dev_attr_groups,
+	.reg_read32		= nvme_pci_reg_read32,
+	.reg_write32		= nvme_pci_reg_write32,
+	.reg_read64		= nvme_pci_reg_read64,
+	.free_ctrl		= nvme_pci_free_ctrl,
+	.submit_async_event	= nvme_pci_submit_async_event,
+	.get_address		= nvme_pci_get_address,
+	.print_device_info	= nvme_pci_print_device_info,
+	.supports_pci_p2pdma	= nvme_pci_supports_pci_p2pdma,
+};
+
+static int nvme_dev_map(struct nvme_dev *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	if (pci_request_mem_regions(pdev, "nvme"))
+		return -ENODEV;
+
+	if (nvme_remap_bar(dev, NVME_REG_DBS + 4096))
+		goto release;
+
+	return 0;
+  release:
+	pci_release_mem_regions(pdev);
+	return -ENODEV;
+}
+
+static unsigned long check_vendor_combination_bug(struct pci_dev *pdev)
+{
+	if (pdev->vendor == 0x144d && pdev->device == 0xa802) {
+		/*
+		 * Several Samsung devices seem to drop off the PCIe bus
+		 * randomly when APST is on and uses the deepest sleep state.
+		 * This has been observed on a Samsung "SM951 NVMe SAMSUNG
+		 * 256GB", a "PM951 NVMe SAMSUNG 512GB", and a "Samsung SSD
+		 * 950 PRO 256GB", but it seems to be restricted to two Dell
+		 * laptops.
+		 */
+		if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.") &&
+		    (dmi_match(DMI_PRODUCT_NAME, "XPS 15 9550") ||
+		     dmi_match(DMI_PRODUCT_NAME, "Precision 5510")))
+			return NVME_QUIRK_NO_DEEPEST_PS;
+	} else if (pdev->vendor == 0x144d && pdev->device == 0xa804) {
+		/*
+		 * Samsung SSD 960 EVO drops off the PCIe bus after system
+		 * suspend on a Ryzen board, ASUS PRIME B350M-A, as well as
+		 * within few minutes after bootup on a Coffee Lake board -
+		 * ASUS PRIME Z370-A
+		 */
+		if (dmi_match(DMI_BOARD_VENDOR, "ASUSTeK COMPUTER INC.") &&
+		    (dmi_match(DMI_BOARD_NAME, "PRIME B350M-A") ||
+		     dmi_match(DMI_BOARD_NAME, "PRIME Z370-A")))
+			return NVME_QUIRK_NO_APST;
+	} else if ((pdev->vendor == 0x144d && (pdev->device == 0xa801 ||
+		    pdev->device == 0xa808 || pdev->device == 0xa809)) ||
+		   (pdev->vendor == 0x1e0f && pdev->device == 0x0001)) {
+		/*
+		 * Forcing to use host managed nvme power settings for
+		 * lowest idle power with quick resume latency on
+		 * Samsung and Toshiba SSDs based on suspend behavior
+		 * on Coffee Lake board for LENOVO C640
+		 */
+		if ((dmi_match(DMI_BOARD_VENDOR, "LENOVO")) &&
+		     dmi_match(DMI_BOARD_NAME, "LNVNB161216"))
+			return NVME_QUIRK_SIMPLE_SUSPEND;
+	} else if (pdev->vendor == 0x2646 && (pdev->device == 0x2263 ||
+		   pdev->device == 0x500f)) {
+		/*
+		 * Exclude some Kingston NV1 and A2000 devices from
+		 * NVME_QUIRK_SIMPLE_SUSPEND. Do a full suspend to save a
+		 * lot fo energy with s2idle sleep on some TUXEDO platforms.
+		 */
+		if (dmi_match(DMI_BOARD_NAME, "NS5X_NS7XAU") ||
+		    dmi_match(DMI_BOARD_NAME, "NS5x_7xAU") ||
+		    dmi_match(DMI_BOARD_NAME, "NS5x_7xPU") ||
+		    dmi_match(DMI_BOARD_NAME, "PH4PRX1_PH6PRX1"))
+			return NVME_QUIRK_FORCE_NO_SIMPLE_SUSPEND;
+	}
+
+	return 0;
+}
+
+static struct nvme_dev *nvme_pci_alloc_dev(struct pci_dev *pdev,
+		const struct pci_device_id *id)
+{
+	unsigned long quirks = id->driver_data;
+	int node = dev_to_node(&pdev->dev);
+	struct nvme_dev *dev;
+	int ret = -ENOMEM;
+
+	dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, node);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+	INIT_WORK(&dev->ctrl.reset_work, nvme_reset_work);
+	mutex_init(&dev->shutdown_lock);
+
+	dev->nr_write_queues = write_queues;
+	dev->nr_poll_queues = poll_queues;
+	dev->nr_allocated_queues = nvme_max_io_queues(dev) + 1;
+	dev->queues = kcalloc_node(dev->nr_allocated_queues,
+			sizeof(struct nvme_queue), GFP_KERNEL, node);
+	if (!dev->queues)
+		goto out_free_dev;
+
+	dev->dev = get_device(&pdev->dev);
+
+	quirks |= check_vendor_combination_bug(pdev);
+	if (!noacpi &&
+	    !(quirks & NVME_QUIRK_FORCE_NO_SIMPLE_SUSPEND) &&
+	    acpi_storage_d3(&pdev->dev)) {
+		/*
+		 * Some systems use a bios work around to ask for D3 on
+		 * platforms that support kernel managed suspend.
+		 */
+		dev_info(&pdev->dev,
+			 "platform quirk: setting simple suspend\n");
+		quirks |= NVME_QUIRK_SIMPLE_SUSPEND;
+	}
+	ret = nvme_init_ctrl(&dev->ctrl, &pdev->dev, &nvme_pci_ctrl_ops,
+			     quirks);
+	if (ret)
+		goto out_put_device;
+
+	if (dev->ctrl.quirks & NVME_QUIRK_DMA_ADDRESS_BITS_48)
+		dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(48));
+	else
+		dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	dma_set_min_align_mask(&pdev->dev, NVME_CTRL_PAGE_SIZE - 1);
+	dma_set_max_seg_size(&pdev->dev, 0xffffffff);
+
+	/*
+	 * Limit the max command size to prevent iod->sg allocations going
+	 * over a single page.
+	 */
+	dev->ctrl.max_hw_sectors = min_t(u32,
+		NVME_MAX_KB_SZ << 1, dma_opt_mapping_size(&pdev->dev) >> 9);
+	dev->ctrl.max_segments = NVME_MAX_SEGS;
+
+	/*
+	 * There is no support for SGLs for metadata (yet), so we are limited to
+	 * a single integrity segment for the separate metadata pointer.
+	 */
+	dev->ctrl.max_integrity_segments = 1;
+	return dev;
+
+out_put_device:
+	put_device(dev->dev);
+	kfree(dev->queues);
+out_free_dev:
+	kfree(dev);
+	return ERR_PTR(ret);
+}
+
+static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct nvme_dev *dev;
+	int result = -ENOMEM;
+
+	dev = nvme_pci_alloc_dev(pdev, id);
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
+
+	result = nvme_dev_map(dev);
+	if (result)
+		goto out_uninit_ctrl;
+
+	result = nvme_setup_prp_pools(dev);
+	if (result)
+		goto out_dev_unmap;
+
+	result = nvme_pci_alloc_iod_mempool(dev);
+	if (result)
+		goto out_release_prp_pools;
+
+	dev_info(dev->ctrl.device, "pci function %s\n", dev_name(&pdev->dev));
+
+	result = nvme_pci_enable(dev);
+	if (result)
+		goto out_release_iod_mempool;
+
+	result = nvme_alloc_admin_tag_set(&dev->ctrl, &dev->admin_tagset,
+				&nvme_mq_admin_ops, sizeof(struct nvme_iod));
+	if (result)
+		goto out_disable;
+
+	/*
+	 * Mark the controller as connecting before sending admin commands to
+	 * allow the timeout handler to do the right thing.
+	 */
+	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_CONNECTING)) {
+		dev_warn(dev->ctrl.device,
+			"failed to mark controller CONNECTING\n");
+		result = -EBUSY;
+		goto out_disable;
+	}
+
+	result = nvme_init_ctrl_finish(&dev->ctrl, false);
+	if (result)
+		goto out_disable;
+
+	nvme_dbbuf_dma_alloc(dev);
+
+	result = nvme_setup_host_mem(dev);
+	if (result < 0)
+		goto out_disable;
+
+	result = nvme_setup_io_queues(dev);
+	if (result)
+		goto out_disable;
+
+	if (dev->online_queues > 1) {
+		nvme_alloc_io_tag_set(&dev->ctrl, &dev->tagset, &nvme_mq_ops,
+				nvme_pci_nr_maps(dev), sizeof(struct nvme_iod));
+		nvme_dbbuf_set(dev);
+	}
+
+	if (!dev->ctrl.tagset)
+		dev_warn(dev->ctrl.device, "IO queues not created\n");
+
+	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_LIVE)) {
+		dev_warn(dev->ctrl.device,
+			"failed to mark controller live state\n");
+		result = -ENODEV;
+		goto out_disable;
+	}
+
+	pci_set_drvdata(pdev, dev);
+
+	nvme_start_ctrl(&dev->ctrl);
+	nvme_put_ctrl(&dev->ctrl);
+	flush_work(&dev->ctrl.scan_work);
+	return 0;
+
+out_disable:
+	nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
+	nvme_dev_disable(dev, true);
+	nvme_free_host_mem(dev);
+	nvme_dev_remove_admin(dev);
+	nvme_dbbuf_dma_free(dev);
+	nvme_free_queues(dev, 0);
+out_release_iod_mempool:
+	mempool_destroy(dev->iod_mempool);
+out_release_prp_pools:
+	nvme_release_prp_pools(dev);
+out_dev_unmap:
+	nvme_dev_unmap(dev);
+out_uninit_ctrl:
+	nvme_uninit_ctrl(&dev->ctrl);
+	nvme_put_ctrl(&dev->ctrl);
+	return result;
+}
+
+static void nvme_reset_prepare(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	/*
+	 * We don't need to check the return value from waiting for the reset
+	 * state as pci_dev device lock is held, making it impossible to race
+	 * with ->remove().
+	 */
+	nvme_disable_prepare_reset(dev, false);
+	nvme_sync_queues(&dev->ctrl);
+}
+
+static void nvme_reset_done(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	if (!nvme_try_sched_reset(&dev->ctrl))
+		flush_work(&dev->ctrl.reset_work);
+}
+
+static void nvme_shutdown(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	nvme_disable_prepare_reset(dev, true);
+}
+
+/*
+ * The driver's remove may be called on a device in a partially initialized
+ * state. This function must not have any dependencies on the device state in
+ * order to proceed.
+ */
+static void nvme_remove(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
+	pci_set_drvdata(pdev, NULL);
+
+	if (!pci_device_is_present(pdev)) {
+		nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DEAD);
+		nvme_dev_disable(dev, true);
+	}
+
+	flush_work(&dev->ctrl.reset_work);
+	nvme_stop_ctrl(&dev->ctrl);
+	nvme_remove_namespaces(&dev->ctrl);
+	nvme_dev_disable(dev, true);
+	nvme_free_host_mem(dev);
+	nvme_dev_remove_admin(dev);
+	nvme_dbbuf_dma_free(dev);
+	nvme_free_queues(dev, 0);
+	mempool_destroy(dev->iod_mempool);
+	nvme_release_prp_pools(dev);
+	nvme_dev_unmap(dev);
+	nvme_uninit_ctrl(&dev->ctrl);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int nvme_get_power_state(struct nvme_ctrl *ctrl, u32 *ps)
+{
+	return nvme_get_features(ctrl, NVME_FEAT_POWER_MGMT, 0, NULL, 0, ps);
+}
+
+static int nvme_set_power_state(struct nvme_ctrl *ctrl, u32 ps)
+{
+	return nvme_set_features(ctrl, NVME_FEAT_POWER_MGMT, ps, NULL, 0, NULL);
+}
+
+static int nvme_resume(struct device *dev)
+{
+	struct nvme_dev *ndev = pci_get_drvdata(to_pci_dev(dev));
+	struct nvme_ctrl *ctrl = &ndev->ctrl;
+
+	if (ndev->last_ps == U32_MAX ||
+	    nvme_set_power_state(ctrl, ndev->last_ps) != 0)
+		goto reset;
+	if (ctrl->hmpre && nvme_setup_host_mem(ndev))
+		goto reset;
+
+	return 0;
+reset:
+	return nvme_try_sched_reset(ctrl);
+}
+
+static int nvme_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct nvme_dev *ndev = pci_get_drvdata(pdev);
+	struct nvme_ctrl *ctrl = &ndev->ctrl;
+	int ret = -EBUSY;
+
+	ndev->last_ps = U32_MAX;
+
+	/*
+	 * The platform does not remove power for a kernel managed suspend so
+	 * use host managed nvme power settings for lowest idle power if
+	 * possible. This should have quicker resume latency than a full device
+	 * shutdown.  But if the firmware is involved after the suspend or the
+	 * device does not support any non-default power states, shut down the
+	 * device fully.
+	 *
+	 * If ASPM is not enabled for the device, shut down the device and allow
+	 * the PCI bus layer to put it into D3 in order to take the PCIe link
+	 * down, so as to allow the platform to achieve its minimum low-power
+	 * state (which may not be possible if the link is up).
+	 */
+	if (pm_suspend_via_firmware() || !ctrl->npss ||
+	    !pcie_aspm_enabled(pdev) ||
+	    (ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND))
+		return nvme_disable_prepare_reset(ndev, true);
+
+	nvme_start_freeze(ctrl);
+	nvme_wait_freeze(ctrl);
+	nvme_sync_queues(ctrl);
+
+	if (nvme_ctrl_state(ctrl) != NVME_CTRL_LIVE)
+		goto unfreeze;
+
+	/*
+	 * Host memory access may not be successful in a system suspend state,
+	 * but the specification allows the controller to access memory in a
+	 * non-operational power state.
+	 */
+	if (ndev->hmb) {
+		ret = nvme_set_host_mem(ndev, 0);
+		if (ret < 0)
+			goto unfreeze;
+	}
+
+	ret = nvme_get_power_state(ctrl, &ndev->last_ps);
+	if (ret < 0)
+		goto unfreeze;
+
+	/*
+	 * A saved state prevents pci pm from generically controlling the
+	 * device's power. If we're using protocol specific settings, we don't
+	 * want pci interfering.
+	 */
+	pci_save_state(pdev);
+
+	ret = nvme_set_power_state(ctrl, ctrl->npss);
+	if (ret < 0)
+		goto unfreeze;
+
+	if (ret) {
+		/* discard the saved state */
+		pci_load_saved_state(pdev, NULL);
+
+		/*
+		 * Clearing npss forces a controller reset on resume. The
+		 * correct value will be rediscovered then.
+		 */
+		ret = nvme_disable_prepare_reset(ndev, true);
+		ctrl->npss = 0;
+	}
+unfreeze:
+	nvme_unfreeze(ctrl);
+	return ret;
+}
+
+static int nvme_simple_suspend(struct device *dev)
+{
+	struct nvme_dev *ndev = pci_get_drvdata(to_pci_dev(dev));
+
+	return nvme_disable_prepare_reset(ndev, true);
+}
+
+static int nvme_simple_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct nvme_dev *ndev = pci_get_drvdata(pdev);
+
+	return nvme_try_sched_reset(&ndev->ctrl);
+}
+
+static const struct dev_pm_ops nvme_dev_pm_ops = {
+	.suspend	= nvme_suspend,
+	.resume		= nvme_resume,
+	.freeze		= nvme_simple_suspend,
+	.thaw		= nvme_simple_resume,
+	.poweroff	= nvme_simple_suspend,
+	.restore	= nvme_simple_resume,
+};
+#endif /* CONFIG_PM_SLEEP */
+
+static pci_ers_result_t nvme_error_detected(struct pci_dev *pdev,
+						pci_channel_state_t state)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	/*
+	 * A frozen channel requires a reset. When detected, this method will
+	 * shutdown the controller to quiesce. The controller will be restarted
+	 * after the slot reset through driver's slot_reset callback.
+	 */
+	switch (state) {
+	case pci_channel_io_normal:
+		return PCI_ERS_RESULT_CAN_RECOVER;
+	case pci_channel_io_frozen:
+		dev_warn(dev->ctrl.device,
+			"frozen state error detected, reset controller\n");
+		if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING)) {
+			nvme_dev_disable(dev, true);
+			return PCI_ERS_RESULT_DISCONNECT;
+		}
+		nvme_dev_disable(dev, false);
+		return PCI_ERS_RESULT_NEED_RESET;
+	case pci_channel_io_perm_failure:
+		dev_warn(dev->ctrl.device,
+			"failure state error detected, request disconnect\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+static pci_ers_result_t nvme_slot_reset(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	dev_info(dev->ctrl.device, "restart after slot reset\n");
+	pci_restore_state(pdev);
+	if (!nvme_try_sched_reset(&dev->ctrl))
+		nvme_unquiesce_io_queues(&dev->ctrl);
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void nvme_error_resume(struct pci_dev *pdev)
+{
+	struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+	flush_work(&dev->ctrl.reset_work);
+}
+
+static const struct pci_error_handlers nvme_err_handler = {
+	.error_detected	= nvme_error_detected,
+	.slot_reset	= nvme_slot_reset,
+	.resume		= nvme_error_resume,
+	.reset_prepare	= nvme_reset_prepare,
+	.reset_done	= nvme_reset_done,
+};
+
+static const struct pci_device_id nvme_id_table[] = {
+	{ PCI_VDEVICE(INTEL, 0x0953),	/* Intel 750/P3500/P3600/P3700 */
+		.driver_data = NVME_QUIRK_STRIPE_SIZE |
+				NVME_QUIRK_DEALLOCATE_ZEROES, },
+	{ PCI_VDEVICE(INTEL, 0x0a53),	/* Intel P3520 */
+		.driver_data = NVME_QUIRK_STRIPE_SIZE |
+				NVME_QUIRK_DEALLOCATE_ZEROES, },
+	{ PCI_VDEVICE(INTEL, 0x0a54),	/* Intel P4500/P4600 */
+		.driver_data = NVME_QUIRK_STRIPE_SIZE |
+				NVME_QUIRK_DEALLOCATE_ZEROES |
+				NVME_QUIRK_IGNORE_DEV_SUBNQN |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_VDEVICE(INTEL, 0x0a55),	/* Dell Express Flash P4600 */
+		.driver_data = NVME_QUIRK_STRIPE_SIZE |
+				NVME_QUIRK_DEALLOCATE_ZEROES, },
+	{ PCI_VDEVICE(INTEL, 0xf1a5),	/* Intel 600P/P3100 */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS |
+				NVME_QUIRK_MEDIUM_PRIO_SQ |
+				NVME_QUIRK_NO_TEMP_THRESH_CHANGE |
+				NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_VDEVICE(INTEL, 0xf1a6),	/* Intel 760p/Pro 7600p */
+		.driver_data = NVME_QUIRK_IGNORE_DEV_SUBNQN, },
+	{ PCI_VDEVICE(INTEL, 0x5845),	/* Qemu emulated controller */
+		.driver_data = NVME_QUIRK_IDENTIFY_CNS |
+				NVME_QUIRK_DISABLE_WRITE_ZEROES |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_VDEVICE(REDHAT, 0x0010),	/* Qemu emulated controller */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x126f, 0x2263),	/* Silicon Motion unidentified */
+		.driver_data = NVME_QUIRK_NO_NS_DESC_LIST |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1bb1, 0x0100),   /* Seagate Nytro Flash Storage */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY |
+				NVME_QUIRK_NO_NS_DESC_LIST, },
+	{ PCI_DEVICE(0x1c58, 0x0003),	/* HGST adapter */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x1c58, 0x0023),	/* WDC SN200 adapter */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x1c5f, 0x0540),	/* Memblaze Pblaze4 adapter */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x144d, 0xa821),   /* Samsung PM1725 */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x144d, 0xa822),   /* Samsung PM1725a */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY |
+				NVME_QUIRK_DISABLE_WRITE_ZEROES|
+				NVME_QUIRK_IGNORE_DEV_SUBNQN, },
+	{ PCI_DEVICE(0x1987, 0x5012),	/* Phison E12 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1987, 0x5016),	/* Phison E16 */
+		.driver_data = NVME_QUIRK_IGNORE_DEV_SUBNQN |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1987, 0x5019),  /* phison E19 */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1987, 0x5021),   /* Phison E21 */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1b4b, 0x1092),	/* Lexar 256 GB SSD */
+		.driver_data = NVME_QUIRK_NO_NS_DESC_LIST |
+				NVME_QUIRK_IGNORE_DEV_SUBNQN, },
+	{ PCI_DEVICE(0x1cc1, 0x33f8),   /* ADATA IM2P33F8ABR1 1 TB */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x10ec, 0x5762),   /* ADATA SX6000LNP */
+		.driver_data = NVME_QUIRK_IGNORE_DEV_SUBNQN |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x10ec, 0x5763),  /* ADATA SX6000PNP */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1cc1, 0x8201),   /* ADATA SX8200PNP 512GB */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS |
+				NVME_QUIRK_IGNORE_DEV_SUBNQN, },
+	 { PCI_DEVICE(0x1344, 0x5407), /* Micron Technology Inc NVMe SSD */
+		.driver_data = NVME_QUIRK_IGNORE_DEV_SUBNQN },
+	 { PCI_DEVICE(0x1344, 0x6001),   /* Micron Nitro NVMe */
+		 .driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1c5c, 0x1504),   /* SK Hynix PC400 */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1c5c, 0x174a),   /* SK Hynix P31 SSD */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x15b7, 0x2001),   /*  Sandisk Skyhawk */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1d97, 0x2263),   /* SPCC */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x144d, 0xa80b),   /* Samsung PM9B1 256G and 512G */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES |
+				NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x144d, 0xa809),   /* Samsung MZALQ256HBJD 256G */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x144d, 0xa802),   /* Samsung SM953 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1cc4, 0x6303),   /* UMIS RPJTJ512MGE1QDY 512G */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1cc4, 0x6302),   /* UMIS RPJTJ256MGE1QDY 256G */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x2646, 0x2262),   /* KINGSTON SKC2000 NVMe SSD */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
+	{ PCI_DEVICE(0x2646, 0x2263),   /* KINGSTON A2000 NVMe SSD  */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
+	{ PCI_DEVICE(0x2646, 0x5013),   /* Kingston KC3000, Kingston FURY Renegade */
+		.driver_data = NVME_QUIRK_NO_SECONDARY_TEMP_THRESH, },
+	{ PCI_DEVICE(0x2646, 0x5018),   /* KINGSTON OM8SFP4xxxxP OS21012 NVMe SSD */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x2646, 0x5016),   /* KINGSTON OM3PGP4xxxxP OS21011 NVMe SSD */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x2646, 0x501A),   /* KINGSTON OM8PGP4xxxxP OS21005 NVMe SSD */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x2646, 0x501B),   /* KINGSTON OM8PGP4xxxxQ OS21005 NVMe SSD */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x2646, 0x501E),   /* KINGSTON OM3PGP4xxxxQ OS21011 NVMe SSD */
+		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ PCI_DEVICE(0x1f40, 0x1202),   /* Netac Technologies Co. NV3000 NVMe SSD */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1f40, 0x5236),   /* Netac Technologies Co. NV7000 NVMe SSD */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e4B, 0x1001),   /* MAXIO MAP1001 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e4B, 0x1002),   /* MAXIO MAP1002 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e4B, 0x1202),   /* MAXIO MAP1202 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e4B, 0x1602),   /* MAXIO MAP1602 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1cc1, 0x5350),   /* ADATA XPG GAMMIX S50 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1dbe, 0x5236),   /* ADATA XPG GAMMIX S70 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e49, 0x0021),   /* ZHITAI TiPro5000 NVMe SSD */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
+	{ PCI_DEVICE(0x1e49, 0x0041),   /* ZHITAI TiPro7000 NVMe SSD */
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
+	{ PCI_DEVICE(0xc0a9, 0x540a),   /* Crucial P2 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1d97, 0x2263), /* Lexar NM610 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1d97, 0x1d97), /* Lexar NM620 */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1d97, 0x2269), /* Lexar NM760 */
+		.driver_data = NVME_QUIRK_BOGUS_NID |
+				NVME_QUIRK_IGNORE_DEV_SUBNQN, },
+	{ PCI_DEVICE(0x10ec, 0x5763), /* TEAMGROUP T-FORCE CARDEA ZERO Z330 SSD */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x1e4b, 0x1602), /* HS-SSD-FUTURE 2048G  */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(0x10ec, 0x5765), /* TEAMGROUP MP33 2TB SSD */
+		.driver_data = NVME_QUIRK_BOGUS_NID, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x0061),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x0065),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x8061),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd00),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd01),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd02),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001),
+		.driver_data = NVME_QUIRK_SINGLE_VECTOR },
+	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2003) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2005),
+		.driver_data = NVME_QUIRK_SINGLE_VECTOR |
+				NVME_QUIRK_128_BYTES_SQES |
+				NVME_QUIRK_SHARED_TAGS |
+				NVME_QUIRK_SKIP_CID_GEN |
+				NVME_QUIRK_IDENTIFY_CNS },
+	{ PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) },
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, nvme_id_table);
+
+static struct pci_driver nvme_driver = {
+	.name		= "nvme",
+	.id_table	= nvme_id_table,
+	.probe		= nvme_probe,
+	.remove		= nvme_remove,
+	.shutdown	= nvme_shutdown,
+	.driver		= {
+		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
+#ifdef CONFIG_PM_SLEEP
+		.pm		= &nvme_dev_pm_ops,
+#endif
+	},
+	.sriov_configure = pci_sriov_configure_simple,
+	.err_handler	= &nvme_err_handler,
+};
+
+static int __init nvme_init(void)
+{
+	BUILD_BUG_ON(sizeof(struct nvme_create_cq) != 64);
+	BUILD_BUG_ON(sizeof(struct nvme_create_sq) != 64);
+	BUILD_BUG_ON(sizeof(struct nvme_delete_queue) != 64);
+	BUILD_BUG_ON(IRQ_AFFINITY_MAX_SETS < 2);
+	BUILD_BUG_ON(NVME_MAX_SEGS > SGES_PER_PAGE);
+	BUILD_BUG_ON(sizeof(struct scatterlist) * NVME_MAX_SEGS > PAGE_SIZE);
+	BUILD_BUG_ON(nvme_pci_npages_prp() > NVME_MAX_NR_ALLOCATIONS);
+
+	return pci_register_driver(&nvme_driver);
+}
+
+static void __exit nvme_exit(void)
+{
+	pci_unregister_driver(&nvme_driver);
+	flush_workqueue(nvme_wq);
+}
+
+MODULE_AUTHOR("Matthew Wilcox <willy@linux.intel.com>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+module_init(nvme_init);
+module_exit(nvme_exit);