Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1276 insertions, 0 deletions

diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
new file mode 100644
index 000000000..2be8231dc
--- /dev/null
+++ b/drivers/block/sunvdc.c
@@ -0,0 +1,1276 @@
+// 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 gendisk *disk, struct hd_geometry *geo)
+{
+	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, blk_mode_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, 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);
+		/*
+		 * If the port was reset (-ENOTCONN), the dring and the
+		 * LDC channel including all of its mappings are already
+		 * torn down and reallocated - there is nothing to undo
+		 * and @desc must not be touched.
+		 *
+		 * For any other failure the descriptor was never handed
+		 * to the peer: unmap the cookies and free the descriptor
+		 * again, so that a later retry of the request does not
+		 * leak LDC map table entries.
+		 */
+		if (err != -ENOTCONN) {
+			ldc_unmap(port->vio.lp, desc->cookies,
+				  desc->ncookies);
+			desc->hdr.state = VIO_DESC_FREE;
+			rqe->req = NULL;
+		}
+	} 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;
+	int ret;
+
+	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;
+	}
+
+	ret = __send_request(bd->rq);
+	if (ret == -EAGAIN) {
+		spin_unlock_irqrestore(&port->vio.lock, flags);
+		/* already spun for 10msec, defer 10msec and retry */
+		blk_mq_delay_kick_requeue_list(hctx->queue, 10);
+		return BLK_STS_DEV_RESOURCE;
+	} else if (ret < 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 queue_limits lim = {
+		.physical_block_size		= port->vdisk_phys_blksz,
+		.max_hw_sectors			= port->max_xfer_size,
+		/* Each segment in a request is up to an aligned page in size. */
+		.seg_boundary_mask		= PAGE_SIZE - 1,
+		.max_segment_size		= PAGE_SIZE,
+		.max_segments			= port->ring_cookies,
+		.features			= BLK_FEAT_ROTATIONAL,
+	};
+	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, 0);
+	if (err)
+		return err;
+
+	g = blk_mq_alloc_disk(&port->tag_set, &lim, 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;
+
+	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;
+		}
+	}
+
+	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, const void *arg)
+{
+	struct vio_dev *vdev = to_vio_dev(dev);
+	const struct vdc_check_port_data *port_data;
+
+	port_data = (const 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) {
+		put_device(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_obj(*port);
+	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);
+		timer_delete_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;
+	unsigned int memflags;
+
+	/*
+	 * 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);
+
+	memflags = 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, memflags);
+}
+
+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_percpu_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", WQ_PERCPU, 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);