Adding upstream version 6.1.76.upstream/6.1.76upstream

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

1 files changed, 1249 insertions, 0 deletions

diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
new file mode 100644
index 000000000..9fa821fa7
--- /dev/null
+++ b/drivers/block/sunvdc.c
@@ -0,0 +1,1249 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* sunvdc.c: Sun LDOM Virtual Disk Client.
+ *
+ * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/blk-mq.h>
+#include <linux/hdreg.h>
+#include <linux/cdrom.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/scatterlist.h>
+
+#include <asm/vio.h>
+#include <asm/ldc.h>
+
+#define DRV_MODULE_NAME		"sunvdc"
+#define PFX DRV_MODULE_NAME	": "
+#define DRV_MODULE_VERSION	"1.2"
+#define DRV_MODULE_RELDATE	"November 24, 2014"
+
+static char version[] =
+	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
+MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
+MODULE_DESCRIPTION("Sun LDOM virtual disk client driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_MODULE_VERSION);
+
+#define VDC_TX_RING_SIZE	512
+#define VDC_DEFAULT_BLK_SIZE	512
+
+#define MAX_XFER_BLKS		(128 * 1024)
+#define MAX_XFER_SIZE		(MAX_XFER_BLKS / VDC_DEFAULT_BLK_SIZE)
+#define MAX_RING_COOKIES	((MAX_XFER_BLKS / PAGE_SIZE) + 2)
+
+#define WAITING_FOR_LINK_UP	0x01
+#define WAITING_FOR_TX_SPACE	0x02
+#define WAITING_FOR_GEN_CMD	0x04
+#define WAITING_FOR_ANY		-1
+
+#define	VDC_MAX_RETRIES	10
+
+static struct workqueue_struct *sunvdc_wq;
+
+struct vdc_req_entry {
+	struct request		*req;
+};
+
+struct vdc_port {
+	struct vio_driver_state	vio;
+
+	struct gendisk		*disk;
+
+	struct vdc_completion	*cmp;
+
+	u64			req_id;
+	u64			seq;
+	struct vdc_req_entry	rq_arr[VDC_TX_RING_SIZE];
+
+	unsigned long		ring_cookies;
+
+	u64			max_xfer_size;
+	u32			vdisk_block_size;
+	u32			drain;
+
+	u64			ldc_timeout;
+	struct delayed_work	ldc_reset_timer_work;
+	struct work_struct	ldc_reset_work;
+
+	/* The server fills these in for us in the disk attribute
+	 * ACK packet.
+	 */
+	u64			operations;
+	u32			vdisk_size;
+	u8			vdisk_type;
+	u8			vdisk_mtype;
+	u32			vdisk_phys_blksz;
+
+	struct blk_mq_tag_set	tag_set;
+
+	char			disk_name[32];
+};
+
+static void vdc_ldc_reset(struct vdc_port *port);
+static void vdc_ldc_reset_work(struct work_struct *work);
+static void vdc_ldc_reset_timer_work(struct work_struct *work);
+
+static inline struct vdc_port *to_vdc_port(struct vio_driver_state *vio)
+{
+	return container_of(vio, struct vdc_port, vio);
+}
+
+/* Ordered from largest major to lowest */
+static struct vio_version vdc_versions[] = {
+	{ .major = 1, .minor = 2 },
+	{ .major = 1, .minor = 1 },
+	{ .major = 1, .minor = 0 },
+};
+
+static inline int vdc_version_supported(struct vdc_port *port,
+					u16 major, u16 minor)
+{
+	return port->vio.ver.major == major && port->vio.ver.minor >= minor;
+}
+
+#define VDCBLK_NAME	"vdisk"
+static int vdc_major;
+#define PARTITION_SHIFT	3
+
+static inline u32 vdc_tx_dring_avail(struct vio_dring_state *dr)
+{
+	return vio_dring_avail(dr, VDC_TX_RING_SIZE);
+}
+
+static int vdc_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+	struct gendisk *disk = bdev->bd_disk;
+	sector_t nsect = get_capacity(disk);
+	sector_t cylinders = nsect;
+
+	geo->heads = 0xff;
+	geo->sectors = 0x3f;
+	sector_div(cylinders, geo->heads * geo->sectors);
+	geo->cylinders = cylinders;
+	if ((sector_t)(geo->cylinders + 1) * geo->heads * geo->sectors < nsect)
+		geo->cylinders = 0xffff;
+
+	return 0;
+}
+
+/* Add ioctl/CDROM_GET_CAPABILITY to support cdrom_id in udev
+ * when vdisk_mtype is VD_MEDIA_TYPE_CD or VD_MEDIA_TYPE_DVD.
+ * Needed to be able to install inside an ldom from an iso image.
+ */
+static int vdc_ioctl(struct block_device *bdev, fmode_t mode,
+		     unsigned command, unsigned long argument)
+{
+	struct vdc_port *port = bdev->bd_disk->private_data;
+	int i;
+
+	switch (command) {
+	case CDROMMULTISESSION:
+		pr_debug(PFX "Multisession CDs not supported\n");
+		for (i = 0; i < sizeof(struct cdrom_multisession); i++)
+			if (put_user(0, (char __user *)(argument + i)))
+				return -EFAULT;
+		return 0;
+
+	case CDROM_GET_CAPABILITY:
+		if (!vdc_version_supported(port, 1, 1))
+			return -EINVAL;
+		switch (port->vdisk_mtype) {
+		case VD_MEDIA_TYPE_CD:
+		case VD_MEDIA_TYPE_DVD:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	default:
+		pr_debug(PFX "ioctl %08x not supported\n", command);
+		return -EINVAL;
+	}
+}
+
+static const struct block_device_operations vdc_fops = {
+	.owner		= THIS_MODULE,
+	.getgeo		= vdc_getgeo,
+	.ioctl		= vdc_ioctl,
+	.compat_ioctl	= blkdev_compat_ptr_ioctl,
+};
+
+static void vdc_blk_queue_start(struct vdc_port *port)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	/* restart blk queue when ring is half emptied. also called after
+	 * handshake completes, so check for initial handshake before we've
+	 * allocated a disk.
+	 */
+	if (port->disk && vdc_tx_dring_avail(dr) * 100 / VDC_TX_RING_SIZE >= 50)
+		blk_mq_start_stopped_hw_queues(port->disk->queue, true);
+}
+
+static void vdc_finish(struct vio_driver_state *vio, int err, int waiting_for)
+{
+	if (vio->cmp &&
+	    (waiting_for == -1 ||
+	     vio->cmp->waiting_for == waiting_for)) {
+		vio->cmp->err = err;
+		complete(&vio->cmp->com);
+		vio->cmp = NULL;
+	}
+}
+
+static void vdc_handshake_complete(struct vio_driver_state *vio)
+{
+	struct vdc_port *port = to_vdc_port(vio);
+
+	cancel_delayed_work(&port->ldc_reset_timer_work);
+	vdc_finish(vio, 0, WAITING_FOR_LINK_UP);
+	vdc_blk_queue_start(port);
+}
+
+static int vdc_handle_unknown(struct vdc_port *port, void *arg)
+{
+	struct vio_msg_tag *pkt = arg;
+
+	printk(KERN_ERR PFX "Received unknown msg [%02x:%02x:%04x:%08x]\n",
+	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
+	printk(KERN_ERR PFX "Resetting connection.\n");
+
+	ldc_disconnect(port->vio.lp);
+
+	return -ECONNRESET;
+}
+
+static int vdc_send_attr(struct vio_driver_state *vio)
+{
+	struct vdc_port *port = to_vdc_port(vio);
+	struct vio_disk_attr_info pkt;
+
+	memset(&pkt, 0, sizeof(pkt));
+
+	pkt.tag.type = VIO_TYPE_CTRL;
+	pkt.tag.stype = VIO_SUBTYPE_INFO;
+	pkt.tag.stype_env = VIO_ATTR_INFO;
+	pkt.tag.sid = vio_send_sid(vio);
+
+	pkt.xfer_mode = VIO_DRING_MODE;
+	pkt.vdisk_block_size = port->vdisk_block_size;
+	pkt.max_xfer_size = port->max_xfer_size;
+
+	viodbg(HS, "SEND ATTR xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
+	       pkt.xfer_mode, pkt.vdisk_block_size, pkt.max_xfer_size);
+
+	return vio_ldc_send(&port->vio, &pkt, sizeof(pkt));
+}
+
+static int vdc_handle_attr(struct vio_driver_state *vio, void *arg)
+{
+	struct vdc_port *port = to_vdc_port(vio);
+	struct vio_disk_attr_info *pkt = arg;
+
+	viodbg(HS, "GOT ATTR stype[0x%x] ops[%llx] disk_size[%llu] disk_type[%x] "
+	       "mtype[0x%x] xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
+	       pkt->tag.stype, pkt->operations,
+	       pkt->vdisk_size, pkt->vdisk_type, pkt->vdisk_mtype,
+	       pkt->xfer_mode, pkt->vdisk_block_size,
+	       pkt->max_xfer_size);
+
+	if (pkt->tag.stype == VIO_SUBTYPE_ACK) {
+		switch (pkt->vdisk_type) {
+		case VD_DISK_TYPE_DISK:
+		case VD_DISK_TYPE_SLICE:
+			break;
+
+		default:
+			printk(KERN_ERR PFX "%s: Bogus vdisk_type 0x%x\n",
+			       vio->name, pkt->vdisk_type);
+			return -ECONNRESET;
+		}
+
+		if (pkt->vdisk_block_size > port->vdisk_block_size) {
+			printk(KERN_ERR PFX "%s: BLOCK size increased "
+			       "%u --> %u\n",
+			       vio->name,
+			       port->vdisk_block_size, pkt->vdisk_block_size);
+			return -ECONNRESET;
+		}
+
+		port->operations = pkt->operations;
+		port->vdisk_type = pkt->vdisk_type;
+		if (vdc_version_supported(port, 1, 1)) {
+			port->vdisk_size = pkt->vdisk_size;
+			port->vdisk_mtype = pkt->vdisk_mtype;
+		}
+		if (pkt->max_xfer_size < port->max_xfer_size)
+			port->max_xfer_size = pkt->max_xfer_size;
+		port->vdisk_block_size = pkt->vdisk_block_size;
+
+		port->vdisk_phys_blksz = VDC_DEFAULT_BLK_SIZE;
+		if (vdc_version_supported(port, 1, 2))
+			port->vdisk_phys_blksz = pkt->phys_block_size;
+
+		return 0;
+	} else {
+		printk(KERN_ERR PFX "%s: Attribute NACK\n", vio->name);
+
+		return -ECONNRESET;
+	}
+}
+
+static void vdc_end_special(struct vdc_port *port, struct vio_disk_desc *desc)
+{
+	int err = desc->status;
+
+	vdc_finish(&port->vio, -err, WAITING_FOR_GEN_CMD);
+}
+
+static void vdc_end_one(struct vdc_port *port, struct vio_dring_state *dr,
+			unsigned int index)
+{
+	struct vio_disk_desc *desc = vio_dring_entry(dr, index);
+	struct vdc_req_entry *rqe = &port->rq_arr[index];
+	struct request *req;
+
+	if (unlikely(desc->hdr.state != VIO_DESC_DONE))
+		return;
+
+	ldc_unmap(port->vio.lp, desc->cookies, desc->ncookies);
+	desc->hdr.state = VIO_DESC_FREE;
+	dr->cons = vio_dring_next(dr, index);
+
+	req = rqe->req;
+	if (req == NULL) {
+		vdc_end_special(port, desc);
+		return;
+	}
+
+	rqe->req = NULL;
+
+	blk_mq_end_request(req, desc->status ? BLK_STS_IOERR : 0);
+
+	vdc_blk_queue_start(port);
+}
+
+static int vdc_ack(struct vdc_port *port, void *msgbuf)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct vio_dring_data *pkt = msgbuf;
+
+	if (unlikely(pkt->dring_ident != dr->ident ||
+		     pkt->start_idx != pkt->end_idx ||
+		     pkt->start_idx >= VDC_TX_RING_SIZE))
+		return 0;
+
+	vdc_end_one(port, dr, pkt->start_idx);
+
+	return 0;
+}
+
+static int vdc_nack(struct vdc_port *port, void *msgbuf)
+{
+	/* XXX Implement me XXX */
+	return 0;
+}
+
+static void vdc_event(void *arg, int event)
+{
+	struct vdc_port *port = arg;
+	struct vio_driver_state *vio = &port->vio;
+	unsigned long flags;
+	int err;
+
+	spin_lock_irqsave(&vio->lock, flags);
+
+	if (unlikely(event == LDC_EVENT_RESET)) {
+		vio_link_state_change(vio, event);
+		queue_work(sunvdc_wq, &port->ldc_reset_work);
+		goto out;
+	}
+
+	if (unlikely(event == LDC_EVENT_UP)) {
+		vio_link_state_change(vio, event);
+		goto out;
+	}
+
+	if (unlikely(event != LDC_EVENT_DATA_READY)) {
+		pr_warn(PFX "Unexpected LDC event %d\n", event);
+		goto out;
+	}
+
+	err = 0;
+	while (1) {
+		union {
+			struct vio_msg_tag tag;
+			u64 raw[8];
+		} msgbuf;
+
+		err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
+		if (unlikely(err < 0)) {
+			if (err == -ECONNRESET)
+				vio_conn_reset(vio);
+			break;
+		}
+		if (err == 0)
+			break;
+		viodbg(DATA, "TAG [%02x:%02x:%04x:%08x]\n",
+		       msgbuf.tag.type,
+		       msgbuf.tag.stype,
+		       msgbuf.tag.stype_env,
+		       msgbuf.tag.sid);
+		err = vio_validate_sid(vio, &msgbuf.tag);
+		if (err < 0)
+			break;
+
+		if (likely(msgbuf.tag.type == VIO_TYPE_DATA)) {
+			if (msgbuf.tag.stype == VIO_SUBTYPE_ACK)
+				err = vdc_ack(port, &msgbuf);
+			else if (msgbuf.tag.stype == VIO_SUBTYPE_NACK)
+				err = vdc_nack(port, &msgbuf);
+			else
+				err = vdc_handle_unknown(port, &msgbuf);
+		} else if (msgbuf.tag.type == VIO_TYPE_CTRL) {
+			err = vio_control_pkt_engine(vio, &msgbuf);
+		} else {
+			err = vdc_handle_unknown(port, &msgbuf);
+		}
+		if (err < 0)
+			break;
+	}
+	if (err < 0)
+		vdc_finish(&port->vio, err, WAITING_FOR_ANY);
+out:
+	spin_unlock_irqrestore(&vio->lock, flags);
+}
+
+static int __vdc_tx_trigger(struct vdc_port *port)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct vio_dring_data hdr = {
+		.tag = {
+			.type		= VIO_TYPE_DATA,
+			.stype		= VIO_SUBTYPE_INFO,
+			.stype_env	= VIO_DRING_DATA,
+			.sid		= vio_send_sid(&port->vio),
+		},
+		.dring_ident		= dr->ident,
+		.start_idx		= dr->prod,
+		.end_idx		= dr->prod,
+	};
+	int err, delay;
+	int retries = 0;
+
+	hdr.seq = dr->snd_nxt;
+	delay = 1;
+	do {
+		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
+		if (err > 0) {
+			dr->snd_nxt++;
+			break;
+		}
+		udelay(delay);
+		if ((delay <<= 1) > 128)
+			delay = 128;
+		if (retries++ > VDC_MAX_RETRIES)
+			break;
+	} while (err == -EAGAIN);
+
+	if (err == -ENOTCONN)
+		vdc_ldc_reset(port);
+	return err;
+}
+
+static int __send_request(struct request *req)
+{
+	struct vdc_port *port = req->q->disk->private_data;
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct scatterlist sg[MAX_RING_COOKIES];
+	struct vdc_req_entry *rqe;
+	struct vio_disk_desc *desc;
+	unsigned int map_perm;
+	int nsg, err, i;
+	u64 len;
+	u8 op;
+
+	if (WARN_ON(port->ring_cookies > MAX_RING_COOKIES))
+		return -EINVAL;
+
+	map_perm = LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_IO;
+
+	if (rq_data_dir(req) == READ) {
+		map_perm |= LDC_MAP_W;
+		op = VD_OP_BREAD;
+	} else {
+		map_perm |= LDC_MAP_R;
+		op = VD_OP_BWRITE;
+	}
+
+	sg_init_table(sg, port->ring_cookies);
+	nsg = blk_rq_map_sg(req->q, req, sg);
+
+	len = 0;
+	for (i = 0; i < nsg; i++)
+		len += sg[i].length;
+
+	desc = vio_dring_cur(dr);
+
+	err = ldc_map_sg(port->vio.lp, sg, nsg,
+			 desc->cookies, port->ring_cookies,
+			 map_perm);
+	if (err < 0) {
+		printk(KERN_ERR PFX "ldc_map_sg() failure, err=%d.\n", err);
+		return err;
+	}
+
+	rqe = &port->rq_arr[dr->prod];
+	rqe->req = req;
+
+	desc->hdr.ack = VIO_ACK_ENABLE;
+	desc->req_id = port->req_id;
+	desc->operation = op;
+	if (port->vdisk_type == VD_DISK_TYPE_DISK) {
+		desc->slice = 0xff;
+	} else {
+		desc->slice = 0;
+	}
+	desc->status = ~0;
+	desc->offset = (blk_rq_pos(req) << 9) / port->vdisk_block_size;
+	desc->size = len;
+	desc->ncookies = err;
+
+	/* This has to be a non-SMP write barrier because we are writing
+	 * to memory which is shared with the peer LDOM.
+	 */
+	wmb();
+	desc->hdr.state = VIO_DESC_READY;
+
+	err = __vdc_tx_trigger(port);
+	if (err < 0) {
+		printk(KERN_ERR PFX "vdc_tx_trigger() failure, err=%d\n", err);
+	} else {
+		port->req_id++;
+		dr->prod = vio_dring_next(dr, dr->prod);
+	}
+
+	return err;
+}
+
+static blk_status_t vdc_queue_rq(struct blk_mq_hw_ctx *hctx,
+				 const struct blk_mq_queue_data *bd)
+{
+	struct vdc_port *port = hctx->queue->queuedata;
+	struct vio_dring_state *dr;
+	unsigned long flags;
+
+	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	blk_mq_start_request(bd->rq);
+
+	spin_lock_irqsave(&port->vio.lock, flags);
+
+	/*
+	 * Doing drain, just end the request in error
+	 */
+	if (unlikely(port->drain)) {
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+		return BLK_STS_IOERR;
+	}
+
+	if (unlikely(vdc_tx_dring_avail(dr) < 1)) {
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+		blk_mq_stop_hw_queue(hctx);
+		return BLK_STS_DEV_RESOURCE;
+	}
+
+	if (__send_request(bd->rq) < 0) {
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+		return BLK_STS_IOERR;
+	}
+
+	spin_unlock_irqrestore(&port->vio.lock, flags);
+	return BLK_STS_OK;
+}
+
+static int generic_request(struct vdc_port *port, u8 op, void *buf, int len)
+{
+	struct vio_dring_state *dr;
+	struct vio_completion comp;
+	struct vio_disk_desc *desc;
+	unsigned int map_perm;
+	unsigned long flags;
+	int op_len, err;
+	void *req_buf;
+
+	if (!(((u64)1 << (u64)op) & port->operations))
+		return -EOPNOTSUPP;
+
+	switch (op) {
+	case VD_OP_BREAD:
+	case VD_OP_BWRITE:
+	default:
+		return -EINVAL;
+
+	case VD_OP_FLUSH:
+		op_len = 0;
+		map_perm = 0;
+		break;
+
+	case VD_OP_GET_WCE:
+		op_len = sizeof(u32);
+		map_perm = LDC_MAP_W;
+		break;
+
+	case VD_OP_SET_WCE:
+		op_len = sizeof(u32);
+		map_perm = LDC_MAP_R;
+		break;
+
+	case VD_OP_GET_VTOC:
+		op_len = sizeof(struct vio_disk_vtoc);
+		map_perm = LDC_MAP_W;
+		break;
+
+	case VD_OP_SET_VTOC:
+		op_len = sizeof(struct vio_disk_vtoc);
+		map_perm = LDC_MAP_R;
+		break;
+
+	case VD_OP_GET_DISKGEOM:
+		op_len = sizeof(struct vio_disk_geom);
+		map_perm = LDC_MAP_W;
+		break;
+
+	case VD_OP_SET_DISKGEOM:
+		op_len = sizeof(struct vio_disk_geom);
+		map_perm = LDC_MAP_R;
+		break;
+
+	case VD_OP_SCSICMD:
+		op_len = 16;
+		map_perm = LDC_MAP_RW;
+		break;
+
+	case VD_OP_GET_DEVID:
+		op_len = sizeof(struct vio_disk_devid);
+		map_perm = LDC_MAP_W;
+		break;
+
+	case VD_OP_GET_EFI:
+	case VD_OP_SET_EFI:
+		return -EOPNOTSUPP;
+	}
+
+	map_perm |= LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_IO;
+
+	op_len = (op_len + 7) & ~7;
+	req_buf = kzalloc(op_len, GFP_KERNEL);
+	if (!req_buf)
+		return -ENOMEM;
+
+	if (len > op_len)
+		len = op_len;
+
+	if (map_perm & LDC_MAP_R)
+		memcpy(req_buf, buf, len);
+
+	spin_lock_irqsave(&port->vio.lock, flags);
+
+	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	/* XXX If we want to use this code generically we have to
+	 * XXX handle TX ring exhaustion etc.
+	 */
+	desc = vio_dring_cur(dr);
+
+	err = ldc_map_single(port->vio.lp, req_buf, op_len,
+			     desc->cookies, port->ring_cookies,
+			     map_perm);
+	if (err < 0) {
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+		kfree(req_buf);
+		return err;
+	}
+
+	init_completion(&comp.com);
+	comp.waiting_for = WAITING_FOR_GEN_CMD;
+	port->vio.cmp = &comp;
+
+	desc->hdr.ack = VIO_ACK_ENABLE;
+	desc->req_id = port->req_id;
+	desc->operation = op;
+	desc->slice = 0;
+	desc->status = ~0;
+	desc->offset = 0;
+	desc->size = op_len;
+	desc->ncookies = err;
+
+	/* This has to be a non-SMP write barrier because we are writing
+	 * to memory which is shared with the peer LDOM.
+	 */
+	wmb();
+	desc->hdr.state = VIO_DESC_READY;
+
+	err = __vdc_tx_trigger(port);
+	if (err >= 0) {
+		port->req_id++;
+		dr->prod = vio_dring_next(dr, dr->prod);
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+
+		wait_for_completion(&comp.com);
+		err = comp.err;
+	} else {
+		port->vio.cmp = NULL;
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+	}
+
+	if (map_perm & LDC_MAP_W)
+		memcpy(buf, req_buf, len);
+
+	kfree(req_buf);
+
+	return err;
+}
+
+static int vdc_alloc_tx_ring(struct vdc_port *port)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	unsigned long len, entry_size;
+	int ncookies;
+	void *dring;
+
+	entry_size = sizeof(struct vio_disk_desc) +
+		(sizeof(struct ldc_trans_cookie) * port->ring_cookies);
+	len = (VDC_TX_RING_SIZE * entry_size);
+
+	ncookies = VIO_MAX_RING_COOKIES;
+	dring = ldc_alloc_exp_dring(port->vio.lp, len,
+				    dr->cookies, &ncookies,
+				    (LDC_MAP_SHADOW |
+				     LDC_MAP_DIRECT |
+				     LDC_MAP_RW));
+	if (IS_ERR(dring))
+		return PTR_ERR(dring);
+
+	dr->base = dring;
+	dr->entry_size = entry_size;
+	dr->num_entries = VDC_TX_RING_SIZE;
+	dr->prod = dr->cons = 0;
+	dr->pending = VDC_TX_RING_SIZE;
+	dr->ncookies = ncookies;
+
+	return 0;
+}
+
+static void vdc_free_tx_ring(struct vdc_port *port)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	if (dr->base) {
+		ldc_free_exp_dring(port->vio.lp, dr->base,
+				   (dr->entry_size * dr->num_entries),
+				   dr->cookies, dr->ncookies);
+		dr->base = NULL;
+		dr->entry_size = 0;
+		dr->num_entries = 0;
+		dr->pending = 0;
+		dr->ncookies = 0;
+	}
+}
+
+static int vdc_port_up(struct vdc_port *port)
+{
+	struct vio_completion comp;
+
+	init_completion(&comp.com);
+	comp.err = 0;
+	comp.waiting_for = WAITING_FOR_LINK_UP;
+	port->vio.cmp = &comp;
+
+	vio_port_up(&port->vio);
+	wait_for_completion(&comp.com);
+	return comp.err;
+}
+
+static void vdc_port_down(struct vdc_port *port)
+{
+	ldc_disconnect(port->vio.lp);
+	ldc_unbind(port->vio.lp);
+	vdc_free_tx_ring(port);
+	vio_ldc_free(&port->vio);
+}
+
+static const struct blk_mq_ops vdc_mq_ops = {
+	.queue_rq	= vdc_queue_rq,
+};
+
+static int probe_disk(struct vdc_port *port)
+{
+	struct request_queue *q;
+	struct gendisk *g;
+	int err;
+
+	err = vdc_port_up(port);
+	if (err)
+		return err;
+
+	/* Using version 1.2 means vdisk_phys_blksz should be set unless the
+	 * disk is reserved by another system.
+	 */
+	if (vdc_version_supported(port, 1, 2) && !port->vdisk_phys_blksz)
+		return -ENODEV;
+
+	if (vdc_version_supported(port, 1, 1)) {
+		/* vdisk_size should be set during the handshake, if it wasn't
+		 * then the underlying disk is reserved by another system
+		 */
+		if (port->vdisk_size == -1)
+			return -ENODEV;
+	} else {
+		struct vio_disk_geom geom;
+
+		err = generic_request(port, VD_OP_GET_DISKGEOM,
+				      &geom, sizeof(geom));
+		if (err < 0) {
+			printk(KERN_ERR PFX "VD_OP_GET_DISKGEOM returns "
+			       "error %d\n", err);
+			return err;
+		}
+		port->vdisk_size = ((u64)geom.num_cyl *
+				    (u64)geom.num_hd *
+				    (u64)geom.num_sec);
+	}
+
+	err = blk_mq_alloc_sq_tag_set(&port->tag_set, &vdc_mq_ops,
+			VDC_TX_RING_SIZE, BLK_MQ_F_SHOULD_MERGE);
+	if (err)
+		return err;
+
+	g = blk_mq_alloc_disk(&port->tag_set, port);
+	if (IS_ERR(g)) {
+		printk(KERN_ERR PFX "%s: Could not allocate gendisk.\n",
+		       port->vio.name);
+		err = PTR_ERR(g);
+		goto out_free_tag;
+	}
+
+	port->disk = g;
+	q = g->queue;
+
+	/* Each segment in a request is up to an aligned page in size. */
+	blk_queue_segment_boundary(q, PAGE_SIZE - 1);
+	blk_queue_max_segment_size(q, PAGE_SIZE);
+
+	blk_queue_max_segments(q, port->ring_cookies);
+	blk_queue_max_hw_sectors(q, port->max_xfer_size);
+	g->major = vdc_major;
+	g->first_minor = port->vio.vdev->dev_no << PARTITION_SHIFT;
+	g->minors = 1 << PARTITION_SHIFT;
+	strcpy(g->disk_name, port->disk_name);
+
+	g->fops = &vdc_fops;
+	g->queue = q;
+	g->private_data = port;
+
+	set_capacity(g, port->vdisk_size);
+
+	if (vdc_version_supported(port, 1, 1)) {
+		switch (port->vdisk_mtype) {
+		case VD_MEDIA_TYPE_CD:
+			pr_info(PFX "Virtual CDROM %s\n", port->disk_name);
+			g->flags |= GENHD_FL_REMOVABLE;
+			set_disk_ro(g, 1);
+			break;
+
+		case VD_MEDIA_TYPE_DVD:
+			pr_info(PFX "Virtual DVD %s\n", port->disk_name);
+			g->flags |= GENHD_FL_REMOVABLE;
+			set_disk_ro(g, 1);
+			break;
+
+		case VD_MEDIA_TYPE_FIXED:
+			pr_info(PFX "Virtual Hard disk %s\n", port->disk_name);
+			break;
+		}
+	}
+
+	blk_queue_physical_block_size(q, port->vdisk_phys_blksz);
+
+	pr_info(PFX "%s: %u sectors (%u MB) protocol %d.%d\n",
+	       g->disk_name,
+	       port->vdisk_size, (port->vdisk_size >> (20 - 9)),
+	       port->vio.ver.major, port->vio.ver.minor);
+
+	err = device_add_disk(&port->vio.vdev->dev, g, NULL);
+	if (err)
+		goto out_cleanup_disk;
+
+	return 0;
+
+out_cleanup_disk:
+	put_disk(g);
+out_free_tag:
+	blk_mq_free_tag_set(&port->tag_set);
+	return err;
+}
+
+static struct ldc_channel_config vdc_ldc_cfg = {
+	.event		= vdc_event,
+	.mtu		= 64,
+	.mode		= LDC_MODE_UNRELIABLE,
+};
+
+static struct vio_driver_ops vdc_vio_ops = {
+	.send_attr		= vdc_send_attr,
+	.handle_attr		= vdc_handle_attr,
+	.handshake_complete	= vdc_handshake_complete,
+};
+
+static void print_version(void)
+{
+	static int version_printed;
+
+	if (version_printed++ == 0)
+		printk(KERN_INFO "%s", version);
+}
+
+struct vdc_check_port_data {
+	int	dev_no;
+	char	*type;
+};
+
+static int vdc_device_probed(struct device *dev, void *arg)
+{
+	struct vio_dev *vdev = to_vio_dev(dev);
+	struct vdc_check_port_data *port_data;
+
+	port_data = (struct vdc_check_port_data *)arg;
+
+	if ((vdev->dev_no == port_data->dev_no) &&
+	    (!(strcmp((char *)&vdev->type, port_data->type))) &&
+		dev_get_drvdata(dev)) {
+		/* This device has already been configured
+		 * by vdc_port_probe()
+		 */
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+/* Determine whether the VIO device is part of an mpgroup
+ * by locating all the virtual-device-port nodes associated
+ * with the parent virtual-device node for the VIO device
+ * and checking whether any of these nodes are vdc-ports
+ * which have already been configured.
+ *
+ * Returns true if this device is part of an mpgroup and has
+ * already been probed.
+ */
+static bool vdc_port_mpgroup_check(struct vio_dev *vdev)
+{
+	struct vdc_check_port_data port_data;
+	struct device *dev;
+
+	port_data.dev_no = vdev->dev_no;
+	port_data.type = (char *)&vdev->type;
+
+	dev = device_find_child(vdev->dev.parent, &port_data,
+				vdc_device_probed);
+
+	if (dev)
+		return true;
+
+	return false;
+}
+
+static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+	struct mdesc_handle *hp;
+	struct vdc_port *port;
+	int err;
+	const u64 *ldc_timeout;
+
+	print_version();
+
+	hp = mdesc_grab();
+	if (!hp)
+		return -ENODEV;
+
+	err = -ENODEV;
+	if ((vdev->dev_no << PARTITION_SHIFT) & ~(u64)MINORMASK) {
+		printk(KERN_ERR PFX "Port id [%llu] too large.\n",
+		       vdev->dev_no);
+		goto err_out_release_mdesc;
+	}
+
+	/* Check if this device is part of an mpgroup */
+	if (vdc_port_mpgroup_check(vdev)) {
+		printk(KERN_WARNING
+			"VIO: Ignoring extra vdisk port %s",
+			dev_name(&vdev->dev));
+		goto err_out_release_mdesc;
+	}
+
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port) {
+		err = -ENOMEM;
+		goto err_out_release_mdesc;
+	}
+
+	if (vdev->dev_no >= 26)
+		snprintf(port->disk_name, sizeof(port->disk_name),
+			 VDCBLK_NAME "%c%c",
+			 'a' + ((int)vdev->dev_no / 26) - 1,
+			 'a' + ((int)vdev->dev_no % 26));
+	else
+		snprintf(port->disk_name, sizeof(port->disk_name),
+			 VDCBLK_NAME "%c", 'a' + ((int)vdev->dev_no % 26));
+	port->vdisk_size = -1;
+
+	/* Actual wall time may be double due to do_generic_file_read() doing
+	 * a readahead I/O first, and once that fails it will try to read a
+	 * single page.
+	 */
+	ldc_timeout = mdesc_get_property(hp, vdev->mp, "vdc-timeout", NULL);
+	port->ldc_timeout = ldc_timeout ? *ldc_timeout : 0;
+	INIT_DELAYED_WORK(&port->ldc_reset_timer_work, vdc_ldc_reset_timer_work);
+	INIT_WORK(&port->ldc_reset_work, vdc_ldc_reset_work);
+
+	err = vio_driver_init(&port->vio, vdev, VDEV_DISK,
+			      vdc_versions, ARRAY_SIZE(vdc_versions),
+			      &vdc_vio_ops, port->disk_name);
+	if (err)
+		goto err_out_free_port;
+
+	port->vdisk_block_size = VDC_DEFAULT_BLK_SIZE;
+	port->max_xfer_size = MAX_XFER_SIZE;
+	port->ring_cookies = MAX_RING_COOKIES;
+
+	err = vio_ldc_alloc(&port->vio, &vdc_ldc_cfg, port);
+	if (err)
+		goto err_out_free_port;
+
+	err = vdc_alloc_tx_ring(port);
+	if (err)
+		goto err_out_free_ldc;
+
+	err = probe_disk(port);
+	if (err)
+		goto err_out_free_tx_ring;
+
+	/* Note that the device driver_data is used to determine
+	 * whether the port has been probed.
+	 */
+	dev_set_drvdata(&vdev->dev, port);
+
+	mdesc_release(hp);
+
+	return 0;
+
+err_out_free_tx_ring:
+	vdc_free_tx_ring(port);
+
+err_out_free_ldc:
+	vio_ldc_free(&port->vio);
+
+err_out_free_port:
+	kfree(port);
+
+err_out_release_mdesc:
+	mdesc_release(hp);
+	return err;
+}
+
+static void vdc_port_remove(struct vio_dev *vdev)
+{
+	struct vdc_port *port = dev_get_drvdata(&vdev->dev);
+
+	if (port) {
+		blk_mq_stop_hw_queues(port->disk->queue);
+
+		flush_work(&port->ldc_reset_work);
+		cancel_delayed_work_sync(&port->ldc_reset_timer_work);
+		del_timer_sync(&port->vio.timer);
+
+		del_gendisk(port->disk);
+		put_disk(port->disk);
+		blk_mq_free_tag_set(&port->tag_set);
+
+		vdc_free_tx_ring(port);
+		vio_ldc_free(&port->vio);
+
+		dev_set_drvdata(&vdev->dev, NULL);
+
+		kfree(port);
+	}
+}
+
+static void vdc_requeue_inflight(struct vdc_port *port)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	u32 idx;
+
+	for (idx = dr->cons; idx != dr->prod; idx = vio_dring_next(dr, idx)) {
+		struct vio_disk_desc *desc = vio_dring_entry(dr, idx);
+		struct vdc_req_entry *rqe = &port->rq_arr[idx];
+		struct request *req;
+
+		ldc_unmap(port->vio.lp, desc->cookies, desc->ncookies);
+		desc->hdr.state = VIO_DESC_FREE;
+		dr->cons = vio_dring_next(dr, idx);
+
+		req = rqe->req;
+		if (req == NULL) {
+			vdc_end_special(port, desc);
+			continue;
+		}
+
+		rqe->req = NULL;
+		blk_mq_requeue_request(req, false);
+	}
+}
+
+static void vdc_queue_drain(struct vdc_port *port)
+{
+	struct request_queue *q = port->disk->queue;
+
+	/*
+	 * Mark the queue as draining, then freeze/quiesce to ensure
+	 * that all existing requests are seen in ->queue_rq() and killed
+	 */
+	port->drain = 1;
+	spin_unlock_irq(&port->vio.lock);
+
+	blk_mq_freeze_queue(q);
+	blk_mq_quiesce_queue(q);
+
+	spin_lock_irq(&port->vio.lock);
+	port->drain = 0;
+	blk_mq_unquiesce_queue(q);
+	blk_mq_unfreeze_queue(q);
+}
+
+static void vdc_ldc_reset_timer_work(struct work_struct *work)
+{
+	struct vdc_port *port;
+	struct vio_driver_state *vio;
+
+	port = container_of(work, struct vdc_port, ldc_reset_timer_work.work);
+	vio = &port->vio;
+
+	spin_lock_irq(&vio->lock);
+	if (!(port->vio.hs_state & VIO_HS_COMPLETE)) {
+		pr_warn(PFX "%s ldc down %llu seconds, draining queue\n",
+			port->disk_name, port->ldc_timeout);
+		vdc_queue_drain(port);
+		vdc_blk_queue_start(port);
+	}
+	spin_unlock_irq(&vio->lock);
+}
+
+static void vdc_ldc_reset_work(struct work_struct *work)
+{
+	struct vdc_port *port;
+	struct vio_driver_state *vio;
+	unsigned long flags;
+
+	port = container_of(work, struct vdc_port, ldc_reset_work);
+	vio = &port->vio;
+
+	spin_lock_irqsave(&vio->lock, flags);
+	vdc_ldc_reset(port);
+	spin_unlock_irqrestore(&vio->lock, flags);
+}
+
+static void vdc_ldc_reset(struct vdc_port *port)
+{
+	int err;
+
+	assert_spin_locked(&port->vio.lock);
+
+	pr_warn(PFX "%s ldc link reset\n", port->disk_name);
+	blk_mq_stop_hw_queues(port->disk->queue);
+	vdc_requeue_inflight(port);
+	vdc_port_down(port);
+
+	err = vio_ldc_alloc(&port->vio, &vdc_ldc_cfg, port);
+	if (err) {
+		pr_err(PFX "%s vio_ldc_alloc:%d\n", port->disk_name, err);
+		return;
+	}
+
+	err = vdc_alloc_tx_ring(port);
+	if (err) {
+		pr_err(PFX "%s vio_alloc_tx_ring:%d\n", port->disk_name, err);
+		goto err_free_ldc;
+	}
+
+	if (port->ldc_timeout)
+		mod_delayed_work(system_wq, &port->ldc_reset_timer_work,
+			  round_jiffies(jiffies + HZ * port->ldc_timeout));
+	mod_timer(&port->vio.timer, round_jiffies(jiffies + HZ));
+	return;
+
+err_free_ldc:
+	vio_ldc_free(&port->vio);
+}
+
+static const struct vio_device_id vdc_port_match[] = {
+	{
+		.type = "vdc-port",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(vio, vdc_port_match);
+
+static struct vio_driver vdc_port_driver = {
+	.id_table	= vdc_port_match,
+	.probe		= vdc_port_probe,
+	.remove		= vdc_port_remove,
+	.name		= "vdc_port",
+};
+
+static int __init vdc_init(void)
+{
+	int err;
+
+	sunvdc_wq = alloc_workqueue("sunvdc", 0, 0);
+	if (!sunvdc_wq)
+		return -ENOMEM;
+
+	err = register_blkdev(0, VDCBLK_NAME);
+	if (err < 0)
+		goto out_free_wq;
+
+	vdc_major = err;
+
+	err = vio_register_driver(&vdc_port_driver);
+	if (err)
+		goto out_unregister_blkdev;
+
+	return 0;
+
+out_unregister_blkdev:
+	unregister_blkdev(vdc_major, VDCBLK_NAME);
+	vdc_major = 0;
+
+out_free_wq:
+	destroy_workqueue(sunvdc_wq);
+	return err;
+}
+
+static void __exit vdc_exit(void)
+{
+	vio_unregister_driver(&vdc_port_driver);
+	unregister_blkdev(vdc_major, VDCBLK_NAME);
+	destroy_workqueue(sunvdc_wq);
+}
+
+module_init(vdc_init);
+module_exit(vdc_exit);