Merge branch 'for-4.3/drivers' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe: "On top of the 4.3 core block IO changes, here are the driver related changes for 4.3. Basically just NVMe and nbd this time around: - NVMe: - PRACT PI improvement from Alok Pandey. - Cleanups and improvements on submission queue doorbell and writing, using CMB if available. From Jon Derrick. - From Keith, support for setting queue maximum segments, and reset support. - Also from Jon, fixup of u64 division issue on 32-bit archs and wiring up of the reset support through and ioctl. - Two small cleanups from Matias and Sunad - Various code cleanups and fixes from Markus Pargmann" * 'for-4.3/drivers' of git://git.kernel.dk/linux-block: NVMe: Using PRACT bit to generate and verify PI by controller NVMe:Remove unreachable code in nvme_abort_req NVMe: Add nvme subsystem reset IOCTL NVMe: Add nvme subsystem reset support NVMe: removed unused nn var from nvme_dev_add NVMe: Set queue max segments nbd: flags is a u32 variable nbd: Rename functions for clearness of recv/send path nbd: Change 'disconnect' to be boolean nbd: Add debugfs entries nbd: Remove variable 'pid' nbd: Move clear queue debug message nbd: Remove 'harderror' and propagate error properly nbd: restructure sock_shutdown nbd: sock_shutdown, remove conditional lock nbd: Fix timeout detection nvme: Fixes u64 division which breaks i386 builds NVMe: Use CMB for the IO SQes if available NVMe: Unify SQ entry writing and doorbell ringing
2026-03-06 15:25:10 -08:00 · 2015-09-02 13:14:58 -07:00
parent 1081230b74 e19b127f5b
commit 52b084d31c
4 changed files with 506 additions and 146 deletions
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -72,6 +72,10 @@ module_param(nvme_char_major, int, 0);
 static int use_threaded_interrupts;
 module_param(use_threaded_interrupts, int, 0);

+static bool use_cmb_sqes = true;
+module_param(use_cmb_sqes, bool, 0644);
+MODULE_PARM_DESC(use_cmb_sqes, "use controller's memory buffer for I/O SQes");
+
 static DEFINE_SPINLOCK(dev_list_lock);
 static LIST_HEAD(dev_list);
 static struct task_struct *nvme_thread;
@@ -103,6 +107,7 @@ struct nvme_queue {
 	char irqname[24];	/* nvme4294967295-65535\0 */
 	spinlock_t q_lock;
 	struct nvme_command *sq_cmds;
+	struct nvme_command __iomem *sq_cmds_io;
 	volatile struct nvme_completion *cqes;
 	struct blk_mq_tags **tags;
 	dma_addr_t sq_dma_addr;
@@ -379,27 +384,28 @@ static void *nvme_finish_cmd(struct nvme_queue *nvmeq, int tag,
 *
 * Safe to use from interrupt context
 */
-static int __nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
+static void __nvme_submit_cmd(struct nvme_queue *nvmeq,
+						struct nvme_command *cmd)
 {
 	u16 tail = nvmeq->sq_tail;

-	memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
+	if (nvmeq->sq_cmds_io)
+		memcpy_toio(&nvmeq->sq_cmds_io[tail], cmd, sizeof(*cmd));
+	else
+		memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
+
 	if (++tail == nvmeq->q_depth)
 		tail = 0;
 	writel(tail, nvmeq->q_db);
 	nvmeq->sq_tail = tail;
-
-	return 0;
 }

-static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
+static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
 {
 	unsigned long flags;
-	int ret;
 	spin_lock_irqsave(&nvmeq->q_lock, flags);
-	ret = __nvme_submit_cmd(nvmeq, cmd);
+	__nvme_submit_cmd(nvmeq, cmd);
 	spin_unlock_irqrestore(&nvmeq->q_lock, flags);
-	return ret;
 }

 static __le64 **iod_list(struct nvme_iod *iod)
@@ -730,18 +736,16 @@ static int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod,
 static void nvme_submit_priv(struct nvme_queue *nvmeq, struct request *req,
 		struct nvme_iod *iod)
 {
-	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+	struct nvme_command cmnd;

-	memcpy(cmnd, req->cmd, sizeof(struct nvme_command));
-	cmnd->rw.command_id = req->tag;
+	memcpy(&cmnd, req->cmd, sizeof(cmnd));
+	cmnd.rw.command_id = req->tag;
 	if (req->nr_phys_segments) {
-		cmnd->rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
-		cmnd->rw.prp2 = cpu_to_le64(iod->first_dma);
+		cmnd.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+		cmnd.rw.prp2 = cpu_to_le64(iod->first_dma);
 	}

-	if (++nvmeq->sq_tail == nvmeq->q_depth)
-		nvmeq->sq_tail = 0;
-	writel(nvmeq->sq_tail, nvmeq->q_db);
+	__nvme_submit_cmd(nvmeq, &cmnd);
 }

 /*
@@ -754,45 +758,41 @@ static void nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
 {
 	struct nvme_dsm_range *range =
 				(struct nvme_dsm_range *)iod_list(iod)[0];
-	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+	struct nvme_command cmnd;

 	range->cattr = cpu_to_le32(0);
 	range->nlb = cpu_to_le32(blk_rq_bytes(req) >> ns->lba_shift);
 	range->slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));

-	memset(cmnd, 0, sizeof(*cmnd));
-	cmnd->dsm.opcode = nvme_cmd_dsm;
-	cmnd->dsm.command_id = req->tag;
-	cmnd->dsm.nsid = cpu_to_le32(ns->ns_id);
-	cmnd->dsm.prp1 = cpu_to_le64(iod->first_dma);
-	cmnd->dsm.nr = 0;
-	cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
+	memset(&cmnd, 0, sizeof(cmnd));
+	cmnd.dsm.opcode = nvme_cmd_dsm;
+	cmnd.dsm.command_id = req->tag;
+	cmnd.dsm.nsid = cpu_to_le32(ns->ns_id);
+	cmnd.dsm.prp1 = cpu_to_le64(iod->first_dma);
+	cmnd.dsm.nr = 0;
+	cmnd.dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);

-	if (++nvmeq->sq_tail == nvmeq->q_depth)
-		nvmeq->sq_tail = 0;
-	writel(nvmeq->sq_tail, nvmeq->q_db);
+	__nvme_submit_cmd(nvmeq, &cmnd);
 }

 static void nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
 								int cmdid)
 {
-	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+	struct nvme_command cmnd;

-	memset(cmnd, 0, sizeof(*cmnd));
-	cmnd->common.opcode = nvme_cmd_flush;
-	cmnd->common.command_id = cmdid;
-	cmnd->common.nsid = cpu_to_le32(ns->ns_id);
+	memset(&cmnd, 0, sizeof(cmnd));
+	cmnd.common.opcode = nvme_cmd_flush;
+	cmnd.common.command_id = cmdid;
+	cmnd.common.nsid = cpu_to_le32(ns->ns_id);

-	if (++nvmeq->sq_tail == nvmeq->q_depth)
-		nvmeq->sq_tail = 0;
-	writel(nvmeq->sq_tail, nvmeq->q_db);
+	__nvme_submit_cmd(nvmeq, &cmnd);
 }

 static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 							struct nvme_ns *ns)
 {
 	struct request *req = iod_get_private(iod);
-	struct nvme_command *cmnd;
+	struct nvme_command cmnd;
 	u16 control = 0;
 	u32 dsmgmt = 0;

@@ -804,19 +804,16 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 	if (req->cmd_flags & REQ_RAHEAD)
 		dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;

-	cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
-	memset(cmnd, 0, sizeof(*cmnd));
+	memset(&cmnd, 0, sizeof(cmnd));
+	cmnd.rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
+	cmnd.rw.command_id = req->tag;
+	cmnd.rw.nsid = cpu_to_le32(ns->ns_id);
+	cmnd.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+	cmnd.rw.prp2 = cpu_to_le64(iod->first_dma);
+	cmnd.rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
+	cmnd.rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);

-	cmnd->rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
-	cmnd->rw.command_id = req->tag;
-	cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
-	cmnd->rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
-	cmnd->rw.prp2 = cpu_to_le64(iod->first_dma);
-	cmnd->rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
-	cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
-
-	if (blk_integrity_rq(req)) {
-		cmnd->rw.metadata = cpu_to_le64(sg_dma_address(iod->meta_sg));
+	if (ns->ms) {
 		switch (ns->pi_type) {
 		case NVME_NS_DPS_PI_TYPE3:
 			control |= NVME_RW_PRINFO_PRCHK_GUARD;
@@ -825,19 +822,21 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 		case NVME_NS_DPS_PI_TYPE2:
 			control |= NVME_RW_PRINFO_PRCHK_GUARD |
 					NVME_RW_PRINFO_PRCHK_REF;
-			cmnd->rw.reftag = cpu_to_le32(
+			cmnd.rw.reftag = cpu_to_le32(
 					nvme_block_nr(ns, blk_rq_pos(req)));
 			break;
 		}
-	} else if (ns->ms)
-		control |= NVME_RW_PRINFO_PRACT;
+		if (blk_integrity_rq(req))
+			cmnd.rw.metadata =
+				cpu_to_le64(sg_dma_address(iod->meta_sg));
+		else
+			control |= NVME_RW_PRINFO_PRACT;
+	}

-	cmnd->rw.control = cpu_to_le16(control);
-	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
+	cmnd.rw.control = cpu_to_le16(control);
+	cmnd.rw.dsmgmt = cpu_to_le32(dsmgmt);

-	if (++nvmeq->sq_tail == nvmeq->q_depth)
-		nvmeq->sq_tail = 0;
-	writel(nvmeq->sq_tail, nvmeq->q_db);
+	__nvme_submit_cmd(nvmeq, &cmnd);

 	return 0;
 }
@@ -1080,7 +1079,8 @@ static int nvme_submit_async_admin_req(struct nvme_dev *dev)
 	c.common.command_id = req->tag;

 	blk_mq_free_request(req);
-	return __nvme_submit_cmd(nvmeq, &c);
+	__nvme_submit_cmd(nvmeq, &c);
+	return 0;
 }

 static int nvme_submit_admin_async_cmd(struct nvme_dev *dev,
@@ -1103,7 +1103,8 @@ static int nvme_submit_admin_async_cmd(struct nvme_dev *dev,

 	cmd->common.command_id = req->tag;

-	return nvme_submit_cmd(nvmeq, cmd);
+	nvme_submit_cmd(nvmeq, cmd);
+	return 0;
 }

 static int adapter_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)
@@ -1315,12 +1316,7 @@ static void nvme_abort_req(struct request *req)

 	dev_warn(nvmeq->q_dmadev, "Aborting I/O %d QID %d\n", req->tag,
 							nvmeq->qid);
-	if (nvme_submit_cmd(dev->queues[0], &cmd) < 0) {
-		dev_warn(nvmeq->q_dmadev,
-				"Could not abort I/O %d QID %d",
-				req->tag, nvmeq->qid);
-		blk_mq_free_request(abort_req);
-	}
+	nvme_submit_cmd(dev->queues[0], &cmd);
 }

 static void nvme_cancel_queue_ios(struct request *req, void *data, bool reserved)
@@ -1374,7 +1370,8 @@ static void nvme_free_queue(struct nvme_queue *nvmeq)
 {
 	dma_free_coherent(nvmeq->q_dmadev, CQ_SIZE(nvmeq->q_depth),
 				(void *)nvmeq->cqes, nvmeq->cq_dma_addr);
-	dma_free_coherent(nvmeq->q_dmadev, SQ_SIZE(nvmeq->q_depth),
+	if (nvmeq->sq_cmds)
+		dma_free_coherent(nvmeq->q_dmadev, SQ_SIZE(nvmeq->q_depth),
 					nvmeq->sq_cmds, nvmeq->sq_dma_addr);
 	kfree(nvmeq);
 }
@@ -1447,6 +1444,47 @@ static void nvme_disable_queue(struct nvme_dev *dev, int qid)
 	spin_unlock_irq(&nvmeq->q_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, dev->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, dev->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, int depth)
+{
+	if (qid && dev->cmb && use_cmb_sqes && NVME_CMB_SQS(dev->cmbsz)) {
+		unsigned offset = (qid - 1) *
+					roundup(SQ_SIZE(depth), dev->page_size);
+		nvmeq->sq_dma_addr = dev->cmb_dma_addr + offset;
+		nvmeq->sq_cmds_io = dev->cmb + offset;
+	} else {
+		nvmeq->sq_cmds = dma_alloc_coherent(dev->dev, SQ_SIZE(depth),
+					&nvmeq->sq_dma_addr, GFP_KERNEL);
+		if (!nvmeq->sq_cmds)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
 static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
 							int depth)
 {
@@ -1459,9 +1497,7 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
 	if (!nvmeq->cqes)
 		goto free_nvmeq;

-	nvmeq->sq_cmds = dma_alloc_coherent(dev->dev, SQ_SIZE(depth),
-					&nvmeq->sq_dma_addr, GFP_KERNEL);
-	if (!nvmeq->sq_cmds)
+	if (nvme_alloc_sq_cmds(dev, nvmeq, qid, depth))
 		goto free_cqdma;

 	nvmeq->q_dmadev = dev->dev;
@@ -1696,6 +1732,12 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
 		page_shift = dev_page_max;
 	}

+	dev->subsystem = readl(&dev->bar->vs) >= NVME_VS(1, 1) ?
+						NVME_CAP_NSSRC(cap) : 0;
+
+	if (dev->subsystem && (readl(&dev->bar->csts) & NVME_CSTS_NSSRO))
+		writel(NVME_CSTS_NSSRO, &dev->bar->csts);
+
 	result = nvme_disable_ctrl(dev, cap);
 	if (result < 0)
 		return result;
@@ -1856,6 +1898,15 @@ static int nvme_user_cmd(struct nvme_dev *dev, struct nvme_ns *ns,
 	return status;
 }

+static int nvme_subsys_reset(struct nvme_dev *dev)
+{
+	if (!dev->subsystem)
+		return -ENOTTY;
+
+	writel(0x4E564D65, &dev->bar->nssr); /* "NVMe" */
+	return 0;
+}
+
 static int nvme_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd,
 							unsigned long arg)
 {
@@ -1989,7 +2040,7 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 								!ns->ext)
 		nvme_init_integrity(ns);

-	if (ns->ms && !blk_get_integrity(disk))
+	if (ns->ms && !(ns->ms == 8 && ns->pi_type) && !blk_get_integrity(disk))
 		set_capacity(disk, 0);
 	else
 		set_capacity(disk, le64_to_cpup(&id->nsze) << (ns->lba_shift - 9));
@@ -2020,7 +2071,10 @@ static int nvme_kthread(void *data)
 		spin_lock(&dev_list_lock);
 		list_for_each_entry_safe(dev, next, &dev_list, node) {
 			int i;
-			if (readl(&dev->bar->csts) & NVME_CSTS_CFS) {
+			u32 csts = readl(&dev->bar->csts);
+
+			if ((dev->subsystem && (csts & NVME_CSTS_NSSRO)) ||
+							csts & NVME_CSTS_CFS) {
 				if (work_busy(&dev->reset_work))
 					continue;
 				list_del_init(&dev->node);
@@ -2080,8 +2134,11 @@ static void nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid)
 	list_add_tail(&ns->list, &dev->namespaces);

 	blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
-	if (dev->max_hw_sectors)
+	if (dev->max_hw_sectors) {
 		blk_queue_max_hw_sectors(ns->queue, dev->max_hw_sectors);
+		blk_queue_max_segments(ns->queue,
+			((dev->max_hw_sectors << 9) / dev->page_size) + 1);
+	}
 	if (dev->stripe_size)
 		blk_queue_chunk_sectors(ns->queue, dev->stripe_size >> 9);
 	if (dev->vwc & NVME_CTRL_VWC_PRESENT)
@@ -2159,6 +2216,58 @@ static int set_queue_count(struct nvme_dev *dev, int count)
 	return min(result & 0xffff, result >> 16) + 1;
 }

+static void __iomem *nvme_map_cmb(struct nvme_dev *dev)
+{
+	u64 szu, size, offset;
+	u32 cmbloc;
+	resource_size_t bar_size;
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	void __iomem *cmb;
+	dma_addr_t dma_addr;
+
+	if (!use_cmb_sqes)
+		return NULL;
+
+	dev->cmbsz = readl(&dev->bar->cmbsz);
+	if (!(NVME_CMB_SZ(dev->cmbsz)))
+		return NULL;
+
+	cmbloc = readl(&dev->bar->cmbloc);
+
+	szu = (u64)1 << (12 + 4 * NVME_CMB_SZU(dev->cmbsz));
+	size = szu * NVME_CMB_SZ(dev->cmbsz);
+	offset = szu * NVME_CMB_OFST(cmbloc);
+	bar_size = pci_resource_len(pdev, NVME_CMB_BIR(cmbloc));
+
+	if (offset > bar_size)
+		return NULL;
+
+	/*
+	 * 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;
+
+	dma_addr = pci_resource_start(pdev, NVME_CMB_BIR(cmbloc)) + offset;
+	cmb = ioremap_wc(dma_addr, size);
+	if (!cmb)
+		return NULL;
+
+	dev->cmb_dma_addr = dma_addr;
+	dev->cmb_size = size;
+	return cmb;
+}
+
+static inline void nvme_release_cmb(struct nvme_dev *dev)
+{
+	if (dev->cmb) {
+		iounmap(dev->cmb);
+		dev->cmb = NULL;
+	}
+}
+
 static size_t db_bar_size(struct nvme_dev *dev, unsigned nr_io_queues)
 {
 	return 4096 + ((nr_io_queues + 1) * 8 * dev->db_stride);
@@ -2177,6 +2286,15 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	if (result < nr_io_queues)
 		nr_io_queues = result;

+	if (dev->cmb && NVME_CMB_SQS(dev->cmbsz)) {
+		result = nvme_cmb_qdepth(dev, nr_io_queues,
+				sizeof(struct nvme_command));
+		if (result > 0)
+			dev->q_depth = result;
+		else
+			nvme_release_cmb(dev);
+	}
+
 	size = db_bar_size(dev, nr_io_queues);
 	if (size > 8192) {
 		iounmap(dev->bar);
@@ -2344,7 +2462,6 @@ static int nvme_dev_add(struct nvme_dev *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 	int res;
-	unsigned nn;
 	struct nvme_id_ctrl *ctrl;
 	int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;

@@ -2354,7 +2471,6 @@ static int nvme_dev_add(struct nvme_dev *dev)
 		return -EIO;
 	}

-	nn = le32_to_cpup(&ctrl->nn);
 	dev->oncs = le16_to_cpup(&ctrl->oncs);
 	dev->abort_limit = ctrl->acl + 1;
 	dev->vwc = ctrl->vwc;
@@ -2440,6 +2556,8 @@ static int nvme_dev_map(struct nvme_dev *dev)
 	dev->q_depth = min_t(int, NVME_CAP_MQES(cap) + 1, NVME_Q_DEPTH);
 	dev->db_stride = 1 << NVME_CAP_STRIDE(cap);
 	dev->dbs = ((void __iomem *)dev->bar) + 4096;
+	if (readl(&dev->bar->vs) >= NVME_VS(1, 2))
+		dev->cmb = nvme_map_cmb(dev);

 	return 0;

@@ -2820,6 +2938,8 @@ static long nvme_dev_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 	case NVME_IOCTL_RESET:
 		dev_warn(dev->dev, "resetting controller\n");
 		return nvme_reset(dev);
+	case NVME_IOCTL_SUBSYS_RESET:
+		return nvme_subsys_reset(dev);
 	default:
 		return -ENOTTY;
 	}
@@ -3145,6 +3265,7 @@ static void nvme_remove(struct pci_dev *pdev)
 	nvme_dev_remove_admin(dev);
 	device_destroy(nvme_class, MKDEV(nvme_char_major, dev->instance));
 	nvme_free_queues(dev, 0);
+	nvme_release_cmb(dev);
 	nvme_release_prp_pools(dev);
 	kref_put(&dev->kref, nvme_free_dev);
 }
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -28,18 +28,32 @@ struct nvme_bar {
 	__u32			cc;	/* Controller Configuration */
 	__u32			rsvd1;	/* Reserved */
 	__u32			csts;	/* Controller Status */
-	__u32			rsvd2;	/* Reserved */
+	__u32			nssr;	/* Subsystem Reset */
 	__u32			aqa;	/* Admin Queue Attributes */
 	__u64			asq;	/* Admin SQ Base Address */
 	__u64			acq;	/* Admin CQ Base Address */
+	__u32			cmbloc; /* Controller Memory Buffer Location */
+	__u32			cmbsz;  /* Controller Memory Buffer Size */
 };

 #define NVME_CAP_MQES(cap)	((cap) & 0xffff)
 #define NVME_CAP_TIMEOUT(cap)	(((cap) >> 24) & 0xff)
 #define NVME_CAP_STRIDE(cap)	(((cap) >> 32) & 0xf)
+#define NVME_CAP_NSSRC(cap)	(((cap) >> 36) & 0x1)
 #define NVME_CAP_MPSMIN(cap)	(((cap) >> 48) & 0xf)
 #define NVME_CAP_MPSMAX(cap)	(((cap) >> 52) & 0xf)

+#define NVME_CMB_BIR(cmbloc)	((cmbloc) & 0x7)
+#define NVME_CMB_OFST(cmbloc)	(((cmbloc) >> 12) & 0xfffff)
+#define NVME_CMB_SZ(cmbsz)	(((cmbsz) >> 12) & 0xfffff)
+#define NVME_CMB_SZU(cmbsz)	(((cmbsz) >> 8) & 0xf)
+
+#define NVME_CMB_WDS(cmbsz)	((cmbsz) & 0x10)
+#define NVME_CMB_RDS(cmbsz)	((cmbsz) & 0x8)
+#define NVME_CMB_LISTS(cmbsz)	((cmbsz) & 0x4)
+#define NVME_CMB_CQS(cmbsz)	((cmbsz) & 0x2)
+#define NVME_CMB_SQS(cmbsz)	((cmbsz) & 0x1)
+
 enum {
 	NVME_CC_ENABLE		= 1 << 0,
 	NVME_CC_CSS_NVM		= 0 << 4,
@@ -55,6 +69,7 @@ enum {
 	NVME_CC_IOCQES		= 4 << 20,
 	NVME_CSTS_RDY		= 1 << 0,
 	NVME_CSTS_CFS		= 1 << 1,
+	NVME_CSTS_NSSRO		= 1 << 4,
 	NVME_CSTS_SHST_NORMAL	= 0 << 2,
 	NVME_CSTS_SHST_OCCUR	= 1 << 2,
 	NVME_CSTS_SHST_CMPLT	= 2 << 2,
@@ -97,9 +112,14 @@ struct nvme_dev {
 	char serial[20];
 	char model[40];
 	char firmware_rev[8];
+	bool subsystem;
 	u32 max_hw_sectors;
 	u32 stripe_size;
 	u32 page_size;
+	void __iomem *cmb;
+	dma_addr_t cmb_dma_addr;
+	u64 cmb_size;
+	u32 cmbsz;
 	u16 oncs;
 	u16 abort_limit;
 	u8 event_limit;
--- a/include/uapi/linux/nvme.h
+++ b/include/uapi/linux/nvme.h
@@ -584,5 +584,6 @@ struct nvme_passthru_cmd {
 #define NVME_IOCTL_SUBMIT_IO	_IOW('N', 0x42, struct nvme_user_io)
 #define NVME_IOCTL_IO_CMD	_IOWR('N', 0x43, struct nvme_passthru_cmd)
 #define NVME_IOCTL_RESET	_IO('N', 0x44)
+#define NVME_IOCTL_SUBSYS_RESET	_IO('N', 0x45)

 #endif /* _UAPI_LINUX_NVME_H */