From: Dan Smith <danms@xxxxxxxxxx>
Subject: Re: [PATCH 1/2] dm-userspace: use ring buffer instead of system call
Date: Fri, 27 Oct 2006 07:01:41 -0700
> FT> It's against on the top of the following patches:
>
> Would you mind sending a patch against a vanilla tree? I'm having a
> hard time getting the patches (old and new) to apply cleanly and in
> the right order.
No problem. Here's the patch against 2.6.18
> FT> In my experiments, the ring buffer interface provides 10% better
> FT> write performance with disktest benchmark, though dbench gives
> FT> comparable performances (about 340 MB/s).
>
> This is good to hear. I am interested in testing it in some of my
> real-life situations where performance is slower due to the high
> latency. This mostly affects the boot time of Xen guests.
>
> I have added kernel caching back into my local version (which only
> adds 200 lines). It improves Xen guest boot performance
> significantly, but does not affect dbench performance. I will be
> interested to see what kind of performance I can get from your
> ringbuffer version, as well as possibly a combination of the two.
I see. I'm looking forward to the results. Then I'll send some other
patches.
---
>From 615787c8a3a716189d6ece9334c451ca9d0d5037 Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Date: Fri, 27 Oct 2006 23:27:28 +0900
Subject: [PATCH] dm-userspace: use ring buffer instead of system call
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
drivers/md/Kconfig | 6
drivers/md/Makefile | 2
drivers/md/dm-user.h | 158 ++++++++
drivers/md/dm-userspace-chardev.c | 777 +++++++++++++++++++++++++++++++++++++
drivers/md/dm-userspace.c | 563 +++++++++++++++++++++++++++
include/linux/dm-userspace.h | 122 ++++++
6 files changed, 1628 insertions(+), 0 deletions(-)
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index bf869ed..714b3b3 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -223,6 +223,12 @@ config DM_SNAPSHOT
---help---
Allow volume managers to take writable snapshots of a device.
+config DM_USERSPACE
+ tristate "Userspace target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM && EXPERIMENTAL
+ ---help---
+ A target that provides a userspace interface to device-mapper
+
config DM_MIRROR
tristate "Mirror target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 34957a6..a123456 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -14,6 +14,7 @@ raid456-objs := raid5.o raid6algos.o rai
raid6altivec1.o raid6altivec2.o raid6altivec4.o \
raid6altivec8.o \
raid6mmx.o raid6sse1.o raid6sse2.o
+dm-user-objs := dm-userspace.o dm-userspace-chardev.o
hostprogs-y := mktables
# Note: link order is important. All raid personalities
@@ -36,6 +37,7 @@ obj-$(CONFIG_DM_MULTIPATH_EMC) += dm-emc
obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
+obj-$(CONFIG_DM_USERSPACE) += dm-user.o
quiet_cmd_unroll = UNROLL $@
cmd_unroll = $(PERL) $(srctree)/$(src)/unroll.pl $(UNROLL) \
diff --git a/drivers/md/dm-user.h b/drivers/md/dm-user.h
new file mode 100644
index 0000000..f1792ec
--- /dev/null
+++ b/drivers/md/dm-user.h
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#ifndef __DM_USER_H
+#define __DM_USER_H
+
+#include <linux/hardirq.h>
+
+#define DMU_KEY_LEN 256
+
+extern struct target_type userspace_target;
+extern mempool_t *request_pool;
+extern dev_t dmu_dev;
+extern spinlock_t devices_lock;
+extern struct list_head devices;
+
+#define DMU_CP_HASH 1024
+
+/*
+ * A block device that we can send bios to
+ */
+struct target_device {
+ struct list_head list; /* Our place in the targets list */
+ struct block_device *bdev; /* The target block_device */
+ struct kref users; /* Self-destructing reference count */
+};
+
+/*
+ * A dm-userspace device, which consists of multiple targets sharing a
+ * common key
+ */
+struct dmu_device {
+ struct list_head list; /* Our place in the devices list */
+
+ spinlock_t lock; /* Protects all the fields below */
+
+ /* We need to protect the TX list with a separate lock that is
+ * always used with IRQs disabled because it is locked from
+ * inside the endio function
+ */
+ spinlock_t tx_lock;
+ struct list_head tx_requests; /* Requests to send to userspace */
+
+ struct list_head rx_requests; /* Requests waiting for reply */
+
+ struct semaphore cp_sem; /* Protection for cp_requests */
+ struct list_head cp_requests; /* Requests waiting to be copied */
+
+ /* Accounting */
+ atomic_t t_reqs; /* Waiting to be sent to userspace */
+ atomic_t r_reqs; /* Waiting for a response from uspace*/
+ atomic_t f_reqs; /* Submitted, waiting for endio */
+ atomic_t total; /* Total requests allocated */
+
+ atomic_t idcounter; /* Counter for making request IDs */
+
+ struct list_head target_devs; /* List of devices we can target */
+
+ void *transport_private; /* Private data for userspace comms */
+
+ char key[DMU_KEY_LEN]; /* Unique name string for device */
+ struct kref users; /* Self-destructing reference count */
+
+ wait_queue_head_t lowmem; /* To block while waiting for memory */
+
+ uint64_t block_size; /* Block size for this device */
+ uint64_t block_mask; /* Mask for offset in block */
+ unsigned int block_shift; /* Shift to convert to/from block */
+
+ struct kcopyd_client *kcopy; /* Interface to kcopyd */
+};
+
+struct dmu_request {
+ struct list_head list; /* Our place on the request queue */
+ struct list_head copy; /* Our place on the copy list */
+ struct dmu_device *dev; /* The DMU device that owns us */
+
+ int type; /* Type of request */
+ uint32_t flags; /* Attribute flags */
+ uint64_t id; /* Unique ID for sync with userspace */
+ union {
+ uint64_t block; /* The block in question */
+ } u;
+
+ struct list_head deps; /* Requests depending on this one */
+ struct bio *bio; /* The bio this request represents */
+
+ struct work_struct task; /* Async task to run for this req */
+
+ struct dmu_msg_map_response response; /* FIXME: Clean this up */
+};
+
+
+extern void add_tx_request(struct dmu_device *dev, struct dmu_request *req);
+extern void endio_worker(void *data);
+
+/* Find and grab a reference to a target device */
+struct target_device *find_target(struct dmu_device *dev,
+ dev_t devno);
+/* Character device transport functions */
+int register_chardev_transport(struct dmu_device *dev);
+void unregister_chardev_transport(struct dmu_device *dev);
+int init_chardev_transport(void);
+void cleanup_chardev_transport(void);
+void write_chardev_transport_info(struct dmu_device *dev,
+ char *buf, unsigned int maxlen);
+
+/* Return the block number for @sector */
+static inline u64 dmu_block(struct dmu_device *dev,
+ sector_t sector)
+{
+ return sector >> dev->block_shift;
+}
+
+/* Return the sector offset in a block for @sector */
+static inline u64 dmu_sector_offset(struct dmu_device *dev,
+ sector_t sector)
+{
+ return sector & dev->block_mask;
+}
+
+/* Return the starting sector for @block */
+static inline u64 dmu_sector(struct dmu_device *dev,
+ uint64_t block)
+{
+ return block << dev->block_shift;
+}
+
+/* Increase the usage count for @dev */
+static inline void get_dev(struct dmu_device *dev)
+{
+ kref_get(&dev->users);
+}
+
+/* Decrease the usage count for @dev */
+void destroy_dmu_device(struct kref *ref);
+static inline void put_dev(struct dmu_device *dev)
+{
+ kref_put(&dev->users, destroy_dmu_device);
+}
+
+#endif
diff --git a/drivers/md/dm-userspace-chardev.c b/drivers/md/dm-userspace-chardev.c
new file mode 100644
index 0000000..4478a97
--- /dev/null
+++ b/drivers/md/dm-userspace-chardev.c
@@ -0,0 +1,777 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@xxxxxxxxxx>
+ *
+ * (C) 2006 FUJITA Tomonori <tomof@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/dm-userspace.h>
+#include <linux/list.h>
+#include <linux/kthread.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <asm/uaccess.h>
+
+#include "dm.h"
+#include "dm-bio-list.h"
+#include "kcopyd.h"
+#include "dm-user.h"
+
+#define DM_MSG_PREFIX "dm-userspace"
+
+/* This allows for a cleaner separation between the dm-userspace
+ * device-mapper target, and the userspace transport used. Right now,
+ * only a chardev transport exists, but it's possible that there could
+ * be more in the future
+ */
+struct dmu_ring {
+ u32 r_idx;
+ unsigned long r_pages[DMU_RING_PAGES];
+ spinlock_t r_lock;
+};
+
+struct chardev_transport {
+ struct cdev cdev;
+ dev_t ctl_dev;
+ struct dmu_device *parent;
+
+ struct dmu_ring tx;
+ struct dmu_ring rx;
+
+ struct task_struct *tx_task;
+ struct task_struct *rx_task;
+
+ wait_queue_head_t tx_wqueue;
+ wait_queue_head_t rx_wqueue;
+ wait_queue_head_t poll_wait;
+};
+
+static inline void dmu_ring_idx_inc(struct dmu_ring *r)
+{
+ if (r->r_idx == DMU_MAX_EVENTS - 1)
+ r->r_idx = 0;
+ else
+ r->r_idx++;
+}
+
+static struct dmu_msg *dmu_head_msg(struct dmu_ring *r, u32 idx)
+{
+ u32 pidx, off;
+
+ pidx = idx / DMU_EVENT_PER_PAGE;
+ off = idx % DMU_EVENT_PER_PAGE;
+
+ return (struct dmu_msg *)
+ (r->r_pages[pidx] + sizeof(struct dmu_msg) * off);
+}
+
+static struct dmu_request *find_rx_request(struct dmu_device *dev,
+ uint64_t id)
+{
+ struct dmu_request *req, *next, *match = NULL;
+
+ spin_lock(&dev->lock);
+ list_for_each_entry_safe(req, next, &dev->rx_requests, list) {
+ if (req->id == id) {
+ list_del_init(&req->list);
+ match = req;
+ atomic_dec(&dev->r_reqs);
+ break;
+ }
+ }
+ spin_unlock(&dev->lock);
+
+ return match;
+}
+
+static int have_pending_requests(struct dmu_device *dev)
+{
+ return atomic_read(&dev->t_reqs) != 0;
+}
+
+static void send_userspace_message(struct dmu_msg *msg,
+ struct dmu_request *req)
+{
+ memset(msg, 0, sizeof(*msg));
+
+ msg->hdr.id = req->id;
+
+ switch (req->type) {
+ case DM_USERSPACE_MAP_BLOCK_REQ:
+ msg->hdr.msg_type = req->type;
+ msg->payload.map_req.org_block = req->u.block;
+ dmu_cpy_flag(&msg->payload.map_req.flags,
+ req->flags, DMU_FLAG_WR);
+ break;
+
+ case DM_USERSPACE_MAP_DONE:
+ msg->hdr.msg_type = DM_USERSPACE_MAP_DONE;
+ msg->payload.map_done.id_of_op = req->id;
+ msg->payload.map_done.org_block = req->u.block;
+ dmu_cpy_flag(&msg->payload.map_done.flags,
+ req->flags, DMU_FLAG_WR);
+ break;
+
+ default:
+ DMWARN("Unknown outgoing message type %i", req->type);
+ }
+
+ /* If this request is not on a list (the rx_requests list),
+ * then it needs to be freed after sending
+ */
+ if (list_empty(&req->list)) {
+ INIT_WORK(&req->task, endio_worker, req);
+ schedule_work(&req->task);
+ }
+}
+
+static void add_rx_request(struct dmu_request *req)
+{
+ spin_lock(&req->dev->lock);
+ list_add_tail(&req->list, &req->dev->rx_requests);
+ atomic_inc(&req->dev->r_reqs);
+ spin_unlock(&req->dev->lock);
+}
+
+struct dmu_request *pluck_next_request(struct dmu_device *dev)
+{
+ struct dmu_request *req = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->tx_lock, flags);
+ if (!list_empty(&dev->tx_requests)) {
+ req = list_entry(dev->tx_requests.next,
+ struct dmu_request, list);
+ list_del_init(&req->list);
+
+ atomic_dec(&dev->t_reqs);
+ }
+ spin_unlock_irqrestore(&dev->tx_lock, flags);
+
+ if (req && ((req->type == DM_USERSPACE_MAP_BLOCK_REQ) ||
+ (req->type == DM_USERSPACE_MAP_DONE)))
+ add_rx_request(req);
+
+ return req;
+}
+
+static struct dmu_msg *get_tx_msg(struct dmu_ring *ring)
+{
+ struct dmu_msg *msg;
+
+ spin_lock(&ring->r_lock);
+ msg = dmu_head_msg(ring, ring->r_idx);
+ if (msg->hdr.status)
+ msg = NULL;
+ else
+ dmu_ring_idx_inc(ring);
+ spin_unlock(&ring->r_lock);
+
+ return msg;
+}
+
+static void send_tx_request(struct dmu_msg *msg, struct dmu_request *req)
+{
+ struct chardev_transport *t = req->dev->transport_private;
+
+ send_userspace_message(msg, req);
+ msg->hdr.status = 1;
+ mb();
+ flush_dcache_page(virt_to_page(msg));
+ wake_up_interruptible(&t->poll_wait);
+}
+
+/* Add a request to a device's request queue */
+void add_tx_request(struct dmu_device *dev, struct dmu_request *req)
+{
+ unsigned long flags;
+ struct chardev_transport *t = dev->transport_private;
+ struct dmu_ring *ring = &t->tx;
+ struct dmu_msg *msg;
+
+ BUG_ON(!list_empty(&req->list));
+
+ msg = get_tx_msg(ring);
+
+ if (msg) {
+ add_rx_request(req);
+ send_tx_request(msg, req);
+ } else {
+ spin_lock_irqsave(&dev->tx_lock, flags);
+ list_add_tail(&req->list, &dev->tx_requests);
+ atomic_inc(&dev->t_reqs);
+ spin_unlock_irqrestore(&dev->tx_lock, flags);
+
+ wake_up_interruptible(&t->tx_wqueue);
+ }
+}
+
+static int dmu_txd(void *data)
+{
+
+ struct dmu_device *dev = data;
+ struct chardev_transport *t = dev->transport_private;
+ struct dmu_ring *ring = &t->tx;
+ struct dmu_request *req = NULL;
+ struct dmu_msg *msg;
+
+ while (!kthread_should_stop()) {
+ msg = dmu_head_msg(ring, ring->r_idx);
+
+ wait_event_interruptible(t->tx_wqueue,
+ (!msg->hdr.status &&
+ have_pending_requests(dev)) ||
+ kthread_should_stop());
+
+ if (kthread_should_stop())
+ break;
+
+ msg = get_tx_msg(ring);
+ if (!msg)
+ continue;
+
+ req = pluck_next_request(dev);
+ BUG_ON(!req);
+
+ send_tx_request(msg, req);
+ }
+
+ return 0;
+}
+
+static struct dmu_request *pluck_dep_req(struct dmu_request *req)
+{
+ struct dmu_request *dreq = NULL;
+
+ if (list_empty(&req->deps)) {
+ /* Delete from cp_requests */
+ list_del_init(&req->copy);
+ } else {
+ /* Get next dependent request */
+ dreq = list_entry(req->deps.next, struct dmu_request, list);
+ list_del_init(&dreq->list);
+ }
+
+ return dreq;
+}
+
+static void flush_block(int read_err, unsigned int write_err, void *data)
+{
+ struct dmu_request *req = data;
+ struct dmu_request *dreq;
+ uint64_t id = req->id;
+
+ if (read_err || write_err) {
+ DMERR("Failed to copy block!");
+ bio_io_error(req->bio, req->bio->bi_size);
+ while ((dreq = pluck_dep_req(req))) {
+ bio_io_error(dreq->bio, dreq->bio->bi_size);
+ }
+ return;
+ }
+
+ atomic_inc(&req->dev->f_reqs);
+ generic_make_request(req->bio);
+
+ down(&req->dev->cp_sem);
+ while ((dreq = pluck_dep_req(req))) {
+ if (id > dreq->id) {
+ printk(KERN_EMERG "Flushing %llu after %llu\n",
+ (unsigned long long) dreq->id,
+ (unsigned long long) id);
+ }
+ id = dreq->id;
+ atomic_inc(&req->dev->f_reqs);
+ generic_make_request(dreq->bio);
+ }
+ up(&req->dev->cp_sem);
+}
+
+static void copy_block(struct dmu_device *dev,
+ struct block_device *src_dev,
+ struct block_device *dst_dev,
+ struct dmu_request *req,
+ uint64_t org_block,
+ uint64_t new_block,
+ int64_t offset)
+{
+ struct io_region src, dst;
+
+ src.bdev = src_dev;
+ src.sector = dmu_sector(dev, org_block);
+ src.count = dev->block_size;
+
+ dst.bdev = dst_dev;
+ dst.sector = dmu_sector(dev, new_block);
+ dst.sector += offset;
+ dst.count = dev->block_size;
+
+ kcopyd_copy(dev->kcopy, &src, 1, &dst, 0, flush_block, req);
+}
+
+/*
+ * Queues @req with a waiting request to the same block, if one
+ * exists. Returns nonzero if queued.
+ */
+static int maybe_queue_dependent_request(struct dmu_request *req,
+ int is_copy_first)
+{
+ struct dmu_request *dreq = NULL;
+ int found = 0;
+
+ BUG_ON(!list_empty(&req->list));
+
+ down(&req->dev->cp_sem);
+
+ list_for_each_entry(dreq, &req->dev->cp_requests, copy) {
+ if (req->u.block == dreq->u.block) {
+ list_add_tail(&req->list, &dreq->deps);
+ found = 1;
+ break;
+ }
+ }
+
+ if (!found && is_copy_first) {
+ BUG_ON(!list_empty(&req->copy));
+ list_add(&req->copy, &req->dev->cp_requests);
+ }
+
+ up(&req->dev->cp_sem);
+
+ return found;
+}
+
+static void map_worker(void *data)
+{
+ struct dmu_request *req = data;
+ struct dmu_msg_map_response *msg = &req->response;
+ struct dmu_device *dev = req->dev;
+ struct target_device *src_dev, *dst_dev;
+ int need_copy = dmu_get_flag(&msg->flags, DMU_FLAG_COPY_FIRST);
+
+ if (need_copy) {
+ src_dev = find_target(dev, MKDEV(msg->src_maj, msg->src_min));
+ if (!src_dev) {
+ DMERR("Failed to find src device %i:%i\n",
+ msg->src_maj, msg->src_min);
+ goto fail;
+ }
+ } else
+ src_dev = NULL;
+
+ dst_dev = find_target(dev, MKDEV(msg->dst_maj, msg->dst_min));
+ if (!dst_dev) {
+ DMERR("Failed to find dest device %i:%i\n",
+ msg->dst_maj, msg->dst_min);
+ goto fail;
+ }
+
+ /* Remap the bio */
+ req->bio->bi_sector = dmu_sector(dev, msg->new_block) +
+ dmu_sector_offset(dev, req->bio->bi_sector) +
+ msg->offset;
+ req->bio->bi_bdev = dst_dev->bdev;
+
+ dmu_cpy_flag(&req->flags, msg->flags, DMU_FLAG_SYNC);
+
+ if (!maybe_queue_dependent_request(req, need_copy)) {
+ if (need_copy)
+ copy_block(dev, src_dev->bdev, dst_dev->bdev, req,
+ req->u.block, msg->new_block,
+ msg->offset);
+ else
+ flush_block(0, 0, req);
+ }
+
+ return;
+
+ fail:
+ bio_io_error(req->bio, req->bio->bi_size);
+}
+
+static void do_map_bio(struct dmu_device *dev,
+ struct dmu_msg_map_response *msg)
+{
+ struct dmu_request *req;
+
+ req = find_rx_request(dev, msg->id_of_req);
+ if (!req) {
+ DMERR("Unable to complete unknown map: %llu\n",
+ (unsigned long long) msg->id_of_req);
+ return;
+ }
+
+ memcpy(&req->response, msg, sizeof(req->response));
+
+ INIT_WORK(&req->task, map_worker, req);
+ schedule_work(&req->task);
+}
+
+static void do_map_done(struct dmu_device *dev, uint64_t id_of_op, int fail)
+{
+ struct dmu_request *req;
+
+ req = find_rx_request(dev, id_of_op);
+ if (!req) {
+ DMERR("Unable to complete unknown request: %llu\n",
+ (unsigned long long) id_of_op);
+ return;
+ }
+
+ dmu_clr_flag(&req->flags, DMU_FLAG_SYNC);
+
+ req->bio->bi_end_io(req->bio, req->bio->bi_size, fail);
+}
+
+static void do_map_failed(struct dmu_device *dev, uint64_t id_of_op)
+{
+ struct dmu_request *req;
+
+ req = find_rx_request(dev, id_of_op);
+ if (!req) {
+ DMERR("Unable to fail unknown request: %llu\n",
+ (unsigned long long) id_of_op);
+ return;
+ }
+
+ DMERR("Userspace failed to map id %llu (sector %llu)",
+ (unsigned long long) id_of_op,
+ (unsigned long long) req->bio->bi_sector);
+
+ bio_io_error(req->bio, req->bio->bi_size);
+
+ mempool_free(req, request_pool);
+}
+
+static int dmu_rxd(void *data)
+{
+ struct dmu_device *dev = (struct dmu_device *) data;
+ struct chardev_transport *t = dev->transport_private;
+ struct dmu_ring *ring = &t->rx;
+ struct dmu_msg *msg;
+
+ while (!kthread_should_stop()) {
+ msg = dmu_head_msg(ring, ring->r_idx);
+ /* do we need this? */
+ flush_dcache_page(virt_to_page(msg));
+
+ wait_event_interruptible(t->rx_wqueue, msg->hdr.status ||
+ kthread_should_stop());
+
+ if (kthread_should_stop())
+ break;
+
+ switch (msg->hdr.msg_type) {
+ case DM_USERSPACE_MAP_BLOCK_RESP:
+ do_map_bio(dev, &msg->payload.map_rsp);
+ break;
+
+ case DM_USERSPACE_MAP_FAILED:
+ do_map_failed(dev, msg->payload.map_rsp.id_of_req);
+ break;
+
+ case DM_USERSPACE_MAP_DONE:
+ do_map_done(dev, msg->payload.map_done.id_of_op, 0);
+ break;
+
+ case DM_USERSPACE_MAP_DONE_FAILED:
+ do_map_done(dev, msg->payload.map_done.id_of_op, 1);
+ break;
+
+ default:
+ DMWARN("Unknown incoming request type: %i",
+ msg->hdr.msg_type);
+ }
+
+ msg->hdr.status = 0;
+ dmu_ring_idx_inc(ring);
+ }
+
+ return 0;
+}
+
+ssize_t dmu_ctl_write(struct file *file, const char __user *buffer,
+ size_t size, loff_t *offset)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ struct chardev_transport *t = dev->transport_private;
+
+ wake_up(&t->tx_wqueue);
+ wake_up(&t->rx_wqueue);
+ return size;
+}
+
+static void dmu_ring_free(struct dmu_ring *r)
+{
+ int i;
+ for (i = 0; i < DMU_RING_PAGES; i++) {
+ if (!r->r_pages[i])
+ break;
+ free_page(r->r_pages[i]);
+ r->r_pages[i] = 0;
+ }
+}
+
+static int dmu_ring_alloc(struct dmu_ring *r)
+{
+ int i;
+
+ r->r_idx = 0;
+ spin_lock_init(&r->r_lock);
+
+ for (i = 0; i < DMU_RING_PAGES; i++) {
+ r->r_pages[i] = get_zeroed_page(GFP_KERNEL);
+ if (!r->r_pages[i])
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+int dmu_ctl_open(struct inode *inode, struct file *file)
+{
+ int ret;
+ struct chardev_transport *t;
+ struct dmu_device *dev;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ t = container_of(inode->i_cdev, struct chardev_transport, cdev);
+ dev = t->parent;
+
+ init_waitqueue_head(&t->poll_wait);
+ init_waitqueue_head(&t->tx_wqueue);
+ init_waitqueue_head(&t->rx_wqueue);
+
+ ret = dmu_ring_alloc(&t->tx);
+ if (ret)
+ return -ENOMEM;
+
+ ret = dmu_ring_alloc(&t->rx);
+ if (ret)
+ goto free_tx;
+
+ t->tx_task = kthread_run(dmu_txd, dev, "%s_tx", DM_MSG_PREFIX);
+ if (!t->tx_task)
+ goto free_rx;
+
+ t->rx_task = kthread_run(dmu_rxd, dev, "%s_rx", DM_MSG_PREFIX);
+ if (!t->rx_task) {
+ ret = -ENOMEM;
+ goto destroy_tx_task;
+ }
+
+ get_dev(dev);
+
+ file->private_data = dev;
+
+ return 0;
+destroy_tx_task:
+ kthread_stop(t->tx_task);
+free_rx:
+ dmu_ring_free(&t->rx);
+free_tx:
+ dmu_ring_free(&t->tx);
+ return ret;
+}
+
+int dmu_ctl_release(struct inode *inode, struct file *file)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ struct chardev_transport *t = dev->transport_private;
+
+ kthread_stop(t->rx_task);
+ kthread_stop(t->tx_task);
+
+ dmu_ring_free(&t->rx);
+ dmu_ring_free(&t->tx);
+
+ put_dev(dev);
+
+ return 0;
+}
+
+unsigned dmu_ctl_poll(struct file *file, poll_table *wait)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ struct chardev_transport *t = dev->transport_private;
+ struct dmu_ring *ring = &t->tx;
+ struct dmu_msg *msg;
+ unsigned mask = 0;
+ u32 idx;
+
+ poll_wait(file, &t->poll_wait, wait);
+
+ spin_lock(&ring->r_lock);
+
+ idx = ring->r_idx ? ring->r_idx - 1 : DMU_MAX_EVENTS - 1;
+ msg = dmu_head_msg(ring, idx);
+ if (msg->hdr.status)
+ mask |= POLLIN | POLLRDNORM;
+
+ spin_unlock(&ring->r_lock);
+
+ return mask;
+}
+
+static int dmu_ring_map(struct vm_area_struct *vma, unsigned long addr,
+ struct dmu_ring *ring)
+{
+ int i, err;
+
+ for (i = 0; i < DMU_RING_PAGES; i++) {
+ struct page *page = virt_to_page(ring->r_pages[i]);
+ err = vm_insert_page(vma, addr, page);
+ if (err)
+ return err;
+ addr += PAGE_SIZE;
+ }
+
+ return 0;
+}
+
+static int dmu_ctl_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ struct chardev_transport *t = dev->transport_private;
+ unsigned long addr;
+ int err;
+
+ if (vma->vm_pgoff)
+ return -EINVAL;
+
+ if (vma->vm_end - vma->vm_start != DMU_RING_SIZE * 2) {
+ DMERR("mmap size must be %lu, not %lu \n",
+ DMU_RING_SIZE * 2, vma->vm_end - vma->vm_start);
+ return -EINVAL;
+ }
+
+ addr = vma->vm_start;
+ err = dmu_ring_map(vma, addr, &t->tx);
+ if (err)
+ return err;
+ err = dmu_ring_map(vma, addr + DMU_RING_SIZE, &t->rx);
+
+ return err;
+}
+
+static struct file_operations ctl_fops = {
+ .open = dmu_ctl_open,
+ .release = dmu_ctl_release,
+ .write = dmu_ctl_write,
+ .mmap = dmu_ctl_mmap,
+ .poll = dmu_ctl_poll,
+ .owner = THIS_MODULE,
+};
+
+static int get_free_minor(void)
+{
+ struct dmu_device *dev;
+ int minor = 0;
+
+ spin_lock(&devices_lock);
+
+ while (1) {
+ list_for_each_entry(dev, &devices, list) {
+ struct chardev_transport *t = dev->transport_private;
+ if (MINOR(t->ctl_dev) == minor)
+ goto dupe;
+ }
+ break;
+ dupe:
+ minor++;
+ }
+
+ spin_unlock(&devices_lock);
+
+ return minor;
+}
+
+int register_chardev_transport(struct dmu_device *dev)
+{
+ struct chardev_transport *t;
+ int ret;
+
+ dev->transport_private = kmalloc(sizeof(struct chardev_transport),
+ GFP_KERNEL);
+ t = dev->transport_private;
+
+ if (!t) {
+ DMERR("Failed to allocate chardev transport");
+ goto bad;
+ }
+
+ t->ctl_dev = MKDEV(MAJOR(dmu_dev), get_free_minor());
+ t->parent = dev;
+
+ cdev_init(&t->cdev, &ctl_fops);
+ t->cdev.owner = THIS_MODULE;
+ t->cdev.ops = &ctl_fops;
+
+ ret = cdev_add(&t->cdev, t->ctl_dev, 1);
+ if (ret < 0) {
+ DMERR("Failed to register control device %d:%d",
+ MAJOR(t->ctl_dev), MINOR(t->ctl_dev));
+ goto bad;
+ }
+
+ return 1;
+
+ bad:
+ kfree(t);
+ return 0;
+}
+
+void unregister_chardev_transport(struct dmu_device *dev)
+{
+ struct chardev_transport *t = dev->transport_private;
+
+ cdev_del(&t->cdev);
+ kfree(t);
+}
+
+int init_chardev_transport(void)
+{
+ int r;
+
+ r = alloc_chrdev_region(&dmu_dev, 0, 10, "dm-userspace");
+ if (r) {
+ DMERR("Failed to allocate chardev region");
+ return 0;
+ } else
+ return 1;
+}
+
+void cleanup_chardev_transport(void)
+{
+ unregister_chrdev_region(dmu_dev, 10);
+}
+
+void write_chardev_transport_info(struct dmu_device *dev,
+ char *buf, unsigned int maxlen)
+{
+ struct chardev_transport *t = dev->transport_private;
+
+ snprintf(buf, maxlen, "%x:%x",
+ MAJOR(t->ctl_dev), MINOR(t->ctl_dev));
+}
diff --git a/drivers/md/dm-userspace.c b/drivers/md/dm-userspace.c
new file mode 100644
index 0000000..b6b8320
--- /dev/null
+++ b/drivers/md/dm-userspace.c
@@ -0,0 +1,563 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/types.h>
+#include <linux/poll.h>
+
+#include <linux/dm-userspace.h>
+
+#include "dm.h"
+#include "dm-bio-list.h"
+#include "kcopyd.h"
+#include "dm-user.h"
+
+#define DMU_COPY_PAGES 256
+
+#define DM_MSG_PREFIX "dm-userspace"
+
+static kmem_cache_t *request_cache;
+mempool_t *request_pool;
+
+spinlock_t devices_lock;
+LIST_HEAD(devices);
+
+/* Device number for the control device */
+dev_t dmu_dev;
+
+void endio_worker(void *data)
+{
+ struct dmu_request *req = data;
+ struct dmu_device *dev = req->dev;
+
+ spin_lock(&dev->lock);
+ if (list_empty(&req->list) && list_empty(&req->copy)) {
+ mempool_free(req, request_pool);
+ atomic_dec(&dev->f_reqs);
+ atomic_dec(&dev->total);
+ wake_up_interruptible(&dev->lowmem);
+ } else {
+ PREPARE_WORK(&req->task, endio_worker, req);
+ schedule_work(&req->task);
+ }
+ spin_unlock(&dev->lock);
+}
+
+/* Return an already-bound target device */
+struct target_device *find_target(struct dmu_device *dev,
+ dev_t devno)
+{
+ struct target_device *target, *match = NULL;
+
+ spin_lock(&dev->lock);
+ list_for_each_entry(target, &dev->target_devs, list) {
+ if (target->bdev->bd_dev == devno) {
+ match = target;
+ break;
+ }
+ }
+ spin_unlock(&dev->lock);
+
+ return match;
+}
+
+/* Find a new target device and bind it to our device */
+static struct target_device *get_target(struct dmu_device *dev,
+ dev_t devno)
+{
+ struct target_device *target;
+ struct block_device *bdev;
+
+ target = find_target(dev, devno);
+ if (target)
+ return target;
+
+ bdev = open_by_devnum(devno, FMODE_READ | FMODE_WRITE);
+ if (IS_ERR(bdev)) {
+ DMERR("Unable to lookup device %x", devno);
+ return NULL;
+ }
+
+ target = kmalloc(sizeof(*target), GFP_KERNEL);
+ if (!target) {
+ DMERR("Unable to alloc new target device");
+ return NULL;
+ }
+
+ target->bdev = bdev;
+ INIT_LIST_HEAD(&target->list);
+
+ if (in_interrupt())
+ printk("%s in irq\n", __FUNCTION__);
+
+ spin_lock(&dev->lock);
+ list_add_tail(&target->list, &dev->target_devs);
+ spin_unlock(&dev->lock);
+
+ return target;
+}
+
+/* Caller must hold dev->lock */
+static void put_target(struct dmu_device *dev,
+ struct target_device *target)
+{
+ list_del(&target->list);
+
+ bd_release(target->bdev);
+ blkdev_put(target->bdev);
+
+ kfree(target);
+}
+
+void destroy_dmu_device(struct kref *ref)
+{
+ struct dmu_device *dev;
+ struct list_head *cursor, *next;
+
+ dev = container_of(ref, struct dmu_device, users);
+
+ spin_lock(&devices_lock);
+ list_del(&dev->list);
+ spin_unlock(&devices_lock);
+
+ list_for_each_safe(cursor, next, &dev->target_devs) {
+ struct target_device *target;
+
+ target = list_entry(cursor,
+ struct target_device,
+ list);
+
+ put_target(dev, target);
+ }
+
+ list_for_each_safe(cursor, next, &dev->tx_requests) {
+ struct dmu_request *req;
+
+ req = list_entry(cursor,
+ struct dmu_request,
+ list);
+
+ DMERR("Failing unsent bio");
+ bio_io_error(req->bio, req->bio->bi_size);
+
+ list_del(&req->list);
+
+ mempool_free(req, request_pool);
+ }
+
+ list_for_each_safe(cursor, next, &dev->rx_requests) {
+ struct dmu_request *req;
+
+ req = list_entry(cursor,
+ struct dmu_request,
+ list);
+
+ DMERR("Failing bio");
+ req->flags = 0;
+ bio_io_error(req->bio, req->bio->bi_size);
+
+ list_del(&req->list);
+
+ mempool_free(req, request_pool);
+ }
+
+ list_for_each_safe(cursor, next, &dev->cp_requests) {
+ struct dmu_request *req;
+
+ req = list_entry(cursor,
+ struct dmu_request,
+ list);
+
+ DMERR("Failing bio");
+ req->flags = 0;
+ bio_io_error(req->bio, req->bio->bi_size);
+
+ list_del(&req->list);
+
+ mempool_free(req, request_pool);
+ }
+
+ kcopyd_client_destroy(dev->kcopy);
+ unregister_chardev_transport(dev);
+
+ kfree(dev);
+}
+
+static int init_dmu_device(struct dmu_device *dev, u32 block_size)
+{
+ int ret;
+
+ init_waitqueue_head(&dev->lowmem);
+ INIT_LIST_HEAD(&dev->list);
+ INIT_LIST_HEAD(&dev->target_devs);
+ kref_init(&dev->users);
+ spin_lock_init(&dev->lock);
+ spin_lock_init(&dev->tx_lock);
+
+ INIT_LIST_HEAD(&dev->tx_requests);
+ INIT_LIST_HEAD(&dev->rx_requests);
+ INIT_LIST_HEAD(&dev->cp_requests);
+
+ dev->block_size = block_size;
+ dev->block_mask = block_size - 1;
+ dev->block_shift = ffs(block_size) - 1;
+
+ atomic_set(&dev->t_reqs, 0);
+ atomic_set(&dev->r_reqs, 0);
+ atomic_set(&dev->f_reqs, 0);
+ atomic_set(&dev->total, 0);
+ atomic_set(&dev->idcounter, 0);
+
+ init_MUTEX(&dev->cp_sem);
+
+ ret = kcopyd_client_create(DMU_COPY_PAGES, &dev->kcopy);
+ if (ret) {
+ DMERR("Failed to initialize kcopyd client");
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct dmu_device *new_dmu_device(char *key,
+ struct dm_target *ti,
+ u32 block_size)
+{
+ struct dmu_device *dev;
+ int ret;
+
+ dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
+ DMERR("Failed to allocate new userspace device");
+ return NULL;
+ }
+
+ if (!init_dmu_device(dev, block_size))
+ goto bad1;
+
+ snprintf(dev->key, DMU_KEY_LEN, "%s", key);
+
+ ret = register_chardev_transport(dev);
+ if (!ret)
+ goto bad2;
+
+ spin_lock(&devices_lock);
+ list_add(&dev->list, &devices);
+ spin_unlock(&devices_lock);
+
+ return dev;
+
+ bad2:
+ put_dev(dev);
+ bad1:
+ kfree(dev);
+ DMERR("Failed to create device");
+ return NULL;
+}
+
+static struct dmu_device *find_dmu_device(const char *key)
+{
+ struct dmu_device *dev;
+ struct dmu_device *match = NULL;
+
+ spin_lock(&devices_lock);
+
+ list_for_each_entry(dev, &devices, list) {
+ spin_lock(&dev->lock);
+ if (strncmp(dev->key, key, DMU_KEY_LEN) == 0) {
+ match = dev;
+ spin_unlock(&dev->lock);
+ break;
+ }
+ spin_unlock(&dev->lock);
+ }
+
+ spin_unlock(&devices_lock);
+
+ return match;
+}
+
+static int dmu_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ uint64_t block_size;
+ struct dmu_device *dev;
+ char *device_key;
+ char *block_size_param;
+ int target_idx = 2;
+
+ if (argc < 3) {
+ ti->error = "Invalid argument count";
+ return -EINVAL;
+ }
+
+ device_key = argv[0];
+ block_size_param = argv[1];
+
+ block_size = simple_strtoul(block_size_param, NULL, 10) / 512;
+
+ dev = find_dmu_device(device_key);
+ if (!dev) {
+ dev = new_dmu_device(device_key, ti, block_size);
+ if (!dev) {
+ ti->error = "Failed to create device";
+ goto bad;
+ }
+ } else
+ get_dev(dev);
+
+ spin_lock(&dev->lock);
+ if (dev->block_size != block_size) {
+ ti->error = "Invalid block size";
+ goto bad;
+ }
+ spin_unlock(&dev->lock);
+
+ /* Resolve target devices */
+ do {
+ int maj, min;
+ sscanf(argv[target_idx], "%i:%i", &maj, &min);
+ if (!get_target(dev, MKDEV(maj, min))) {
+ DMERR("Failed to find target device %i:%i (%s)",
+ maj, min, argv[target_idx]);
+ goto out;
+ }
+ } while (++target_idx < argc);
+
+ ti->private = dev;
+ ti->split_io = block_size;
+
+ return 0;
+
+ bad:
+ if (dev)
+ spin_unlock(&dev->lock);
+ out:
+ if (dev)
+ put_dev(dev);
+
+ return -EINVAL;
+}
+
+static void dmu_dtr(struct dm_target *ti)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+
+ put_dev(dev);
+}
+
+static void init_req(struct dmu_device *dev,
+ struct bio *bio,
+ struct dmu_request *req)
+{
+ req->id = (uint64_t) atomic_add_return(1, &dev->idcounter);
+
+ req->type = DM_USERSPACE_MAP_BLOCK_REQ;
+ req->dev = dev;
+ req->bio = bio;
+ req->u.block = dmu_block(dev, bio->bi_sector);
+ req->flags = 0;
+ INIT_LIST_HEAD(&req->deps);
+ INIT_LIST_HEAD(&req->list);
+ INIT_LIST_HEAD(&req->copy);
+
+ if (bio_rw(bio))
+ dmu_set_flag(&req->flags, DMU_FLAG_WR);
+}
+
+static int dmu_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+ struct dmu_request *req;
+
+ if (unlikely(bio_barrier(bio))) {
+ printk("Refusing bio barrier\n");
+ return -EOPNOTSUPP;
+ }
+
+ wait_event_interruptible(dev->lowmem,
+ atomic_read(&dev->total) <= 20000);
+
+ req = mempool_alloc(request_pool, GFP_NOIO);
+ if (!req) {
+ DMERR("Failed to alloc request");
+ return -1;
+ }
+
+ atomic_inc(&dev->total);
+
+ map_context->ptr = req;
+
+ init_req(dev, bio, req);
+
+ add_tx_request(dev, req);
+
+ return 0;
+}
+
+static int dmu_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+
+ /* FIXME: Remove after debug */
+ spin_lock(&dev->lock);
+ printk("Requests: %u t:%u r:%u f:%u (%c%c%c)\n",
+ atomic_read(&dev->total),
+ atomic_read(&dev->t_reqs),
+ atomic_read(&dev->r_reqs),
+ atomic_read(&dev->f_reqs),
+ list_empty(&dev->tx_requests) ? ' ':'T',
+ list_empty(&dev->rx_requests) ? ' ':'R',
+ list_empty(&dev->cp_requests) ? ' ':'C');
+ spin_unlock(&dev->lock);
+
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ write_chardev_transport_info(dev, result, maxlen);
+ break;
+
+ case STATUSTYPE_TABLE:
+ snprintf(result, maxlen, "%s %llu",
+ dev->key,
+ (unsigned long long) dev->block_size * 512);
+ break;
+ }
+
+ return 0;
+}
+
+static int dmu_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ struct dmu_request *req = map_context->ptr;
+ int ret = 0;
+
+ if (error)
+ return -1;
+
+ if (dmu_get_flag(&req->flags, DMU_FLAG_SYNC)) {
+ req->type = DM_USERSPACE_MAP_DONE;
+ add_tx_request(req->dev, req);
+ ret = 1;
+ } else {
+ INIT_WORK(&req->task, endio_worker, req);
+ schedule_work(&req->task);
+ }
+
+ return ret;
+}
+
+struct target_type userspace_target = {
+ .name = "userspace",
+ .version = {0, 1, 0},
+ .module = THIS_MODULE,
+ .ctr = dmu_ctr,
+ .dtr = dmu_dtr,
+ .map = dmu_map,
+ .status = dmu_status,
+ .end_io = dmu_end_io
+};
+
+int __init dm_userspace_init(void)
+{
+ int r = dm_register_target(&userspace_target);
+ if (r < 0) {
+ DMERR("Register failed %d", r);
+ return 0;
+ }
+
+ spin_lock_init(&devices_lock);
+
+ request_cache =
+ kmem_cache_create("dm-userspace-requests",
+ sizeof(struct dmu_request),
+ __alignof__ (struct dmu_request),
+ 0, NULL, NULL);
+ if (!request_cache) {
+ DMERR("Failed to allocate request cache");
+ goto bad;
+ }
+
+ request_pool = mempool_create(64,
+ mempool_alloc_slab, mempool_free_slab,
+ request_cache);
+ if (!request_pool) {
+ DMERR("Failed to allocate request pool");
+ goto bad2;
+ }
+
+ r = init_chardev_transport();
+ if (!r)
+ goto bad3;
+
+ return 1;
+
+ bad3:
+ mempool_destroy(request_pool);
+ bad2:
+ kmem_cache_destroy(request_cache);
+ bad:
+ dm_unregister_target(&userspace_target);
+
+ return 0;
+}
+
+void __exit dm_userspace_exit(void)
+{
+ int r;
+ struct list_head *cursor, *next;
+ struct dmu_device *dev;
+
+ spin_lock(&devices_lock);
+
+ list_for_each_safe(cursor, next, &devices) {
+ dev = list_entry(cursor, struct dmu_device, list);
+ list_del(cursor);
+ destroy_dmu_device(&dev->users);
+ DMERR("Destroying hanging device %s", dev->key);
+ }
+
+ spin_unlock(&devices_lock);
+
+ cleanup_chardev_transport();
+
+ mempool_destroy(request_pool);
+ kmem_cache_destroy(request_cache);
+
+ r = dm_unregister_target(&userspace_target);
+ if (r < 0)
+ DMERR("unregister failed %d", r);
+}
+
+module_init(dm_userspace_init);
+module_exit(dm_userspace_exit);
+
+MODULE_DESCRIPTION(DM_NAME " userspace target");
+MODULE_AUTHOR("Dan Smith");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/dm-userspace.h b/include/linux/dm-userspace.h
new file mode 100644
index 0000000..e249f51
--- /dev/null
+++ b/include/linux/dm-userspace.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#ifndef __DM_USERSPACE_H
+#define __DM_USERSPACE_H
+
+#include <linux/types.h>
+
+/*
+ * Message Types
+ */
+#define DM_USERSPACE_MAP_BLOCK_REQ 1
+#define DM_USERSPACE_MAP_BLOCK_RESP 2
+#define DM_USERSPACE_MAP_FAILED 3
+#define DM_USERSPACE_MAP_DONE 4
+#define DM_USERSPACE_MAP_DONE_FAILED 5
+
+/*
+ * Flags and associated macros
+ */
+#define DMU_FLAG_VALID 1
+#define DMU_FLAG_WR 2
+#define DMU_FLAG_COPY_FIRST 4
+#define DMU_FLAG_SYNC 8
+
+static inline int dmu_get_flag(uint32_t *flags, uint32_t flag)
+{
+ return (*flags & flag) != 0;
+}
+
+static inline void dmu_set_flag(uint32_t *flags, uint32_t flag)
+{
+ *flags |= flag;
+}
+
+static inline void dmu_clr_flag(uint32_t *flags, uint32_t flag)
+{
+ *flags &= (~flag);
+}
+
+static inline void dmu_cpy_flag(uint32_t *flags, uint32_t src, uint32_t flag)
+{
+ *flags = (*flags & ~flag) | (src & flag);
+}
+
+/*
+ * This message header is sent in front of every message, in both
+ * directions
+ */
+struct dmu_msg_header {
+ uint64_t id;
+ uint32_t msg_type;
+ uint32_t payload_len;
+ uint32_t status;
+ uint32_t padding;
+};
+
+/* DM_USERSPACE_MAP_DONE
+ * DM_USERSPACE_MAP_DONE_FAILED
+ */
+struct dmu_msg_map_done {
+ uint64_t id_of_op;
+ uint64_t org_block;
+ uint32_t flags;
+};
+
+/* DM_USERSPACE_MAP_BLOCK_REQ */
+struct dmu_msg_map_request {
+ uint64_t org_block;
+
+ uint32_t flags;
+};
+
+/* DM_USERSPACE_MAP_BLOCK_RESP
+ * DM_USERSPACE_MAP_BLOCK_FAILED
+ */
+struct dmu_msg_map_response {
+ uint64_t new_block;
+ int64_t offset;
+
+ uint64_t id_of_req;
+ uint32_t flags;
+
+ uint32_t src_maj;
+ uint32_t src_min;
+
+ uint32_t dst_maj;
+ uint32_t dst_min;
+};
+
+/* A full message */
+struct dmu_msg {
+ struct dmu_msg_header hdr;
+ union {
+ struct dmu_msg_map_done map_done;
+ struct dmu_msg_map_request map_req;
+ struct dmu_msg_map_response map_rsp;
+ } payload;
+};
+
+#define DMU_RING_SIZE (1UL << 16)
+#define DMU_RING_PAGES (DMU_RING_SIZE >> PAGE_SHIFT)
+#define DMU_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct dmu_msg))
+#define DMU_MAX_EVENTS (DMU_EVENT_PER_PAGE * DMU_RING_PAGES)
+
+#endif
--
1.4.1
--
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