This adds the dm-userspace kernel device-mapper target. It contains
my latest changes, as well as Fujita's ringbuffer transport.
Comments welcome :)
--
Dan Smith
IBM Linux Technology Center
Open Hypervisor Team
email: danms@xxxxxxxxxx
Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
diff -r 50f87a6ffd94 drivers/md/Kconfig
--- a/drivers/md/Kconfig Thu Jan 25 17:50:37 2007 -0800
+++ b/drivers/md/Kconfig Mon Jan 29 14:28:05 2007 -0800
@@ -236,6 +236,12 @@ 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 -r 50f87a6ffd94 drivers/md/Makefile
--- a/drivers/md/Makefile Thu Jan 25 17:50:37 2007 -0800
+++ b/drivers/md/Makefile Mon Jan 29 14:28:05 2007 -0800
@@ -14,6 +14,8 @@ 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 \
+ dm-userspace-cache.o
hostprogs-y := mktables
# Note: link order is important. All raid personalities
@@ -36,6 +38,7 @@ obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot
obj-$(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 -r 50f87a6ffd94 drivers/md/dm-user.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/md/dm-user.h Mon Jan 29 14:28:05 2007 -0800
@@ -0,0 +1,176 @@
+/*
+ * Copyright IBM 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/dm-userspace.h>
+
+#include <linux/hardirq.h>
+#include <linux/slab.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;
+
+struct dmu_mappings;
+
+#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/RX lists with a separate lock that is
+ * always used with IRQs disabled because it is locked from
+ * inside the endio function
+ */
+ spinlock_t xmit_lock;
+ struct list_head tx_requests; /* Requests to send to userspace */
+ struct list_head *rx_requests; /* Requests waiting for reply */
+
+ struct dmu_mappings *mappings;
+
+ /* 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 */
+
+ unsigned int request_slots; /* Max number of reqs we will queue */
+};
+
+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 */
+
+ struct block_device *target_dev;
+
+ 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(struct work_struct *work);
+
+/* 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);
+}
+
+int dmu_init_mappings(void);
+void dmu_cleanup_mappings(void);
+int dmu_make_mapping(struct dmu_device *dev,
+ uint64_t org, uint64_t new, int64_t offset,
+ struct block_device *dest, int rw);
+int dmu_map_from_mappings(struct dmu_device *dev,
+ struct bio *bio);
+int dmu_alloc_mappings(struct dmu_mappings **m, uint32_t size);
+int dmu_remove_mapping(struct dmu_device *dev, uint64_t org);
+unsigned int dmu_remove_all_mappings(struct dmu_device *dev);
+
+#endif
diff -r 50f87a6ffd94 drivers/md/dm-userspace-cache.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/md/dm-userspace-cache.c Mon Jan 29 14:28:05 2007 -0800
@@ -0,0 +1,256 @@
+/*
+ * Copyright IBM 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 "dm.h"
+
+#include <linux/dm-userspace.h>
+
+#include "dm-user.h"
+
+#define DM_MSG_PREFIX "dm-userspace-cache"
+
+static struct kmem_cache *map_cache;
+
+struct dmu_mappings {
+ struct list_head *table;
+ uint32_t size;
+ uint32_t count;
+ struct semaphore sem;
+};
+
+struct dmu_map {
+ struct list_head list;
+ uint64_t org_block;
+ uint64_t new_block;
+ int64_t offset;
+ struct block_device *dest_dev;
+ int rw;
+};
+
+int dmu_alloc_mappings(struct dmu_mappings **mp, uint32_t size)
+{
+ struct dmu_mappings *m;
+ int i;
+
+ (*mp) = kmalloc(sizeof(*m), GFP_KERNEL);
+ if (!(*mp)) {
+ DMERR("Failed to alloc mappings");
+ return 0;
+ }
+
+ m = *mp;
+
+ m->table = kmalloc(sizeof(struct list_head) * size, GFP_KERNEL);
+ m->size = size;
+ m->count = 0;
+
+ for (i = 0; i < m->size; i++) {
+ INIT_LIST_HEAD(&m->table[i]);
+ }
+
+ init_MUTEX(&m->sem);
+
+ return 1;
+}
+
+int dmu_destroy_mappings(struct dmu_mappings *m)
+{
+ if (m->table)
+ kfree(m->table);
+
+ return 1;
+}
+
+static struct dmu_map *__dmu_find_mapping(struct dmu_mappings *m,
+ uint64_t block)
+{
+ uint32_t bucket;
+ struct dmu_map *map;
+
+ bucket = ((uint32_t)block) % m->size;
+
+ list_for_each_entry(map, &m->table[bucket], list) {
+ if (map->org_block == block)
+ return map;
+ }
+
+ return NULL;
+}
+
+static void __dmu_delete_mapping(struct dmu_mappings *m,
+ struct dmu_map *map)
+{
+ m->count--;
+ list_del(&map->list);
+ kmem_cache_free(map_cache, map);
+}
+
+static int dmu_add_mapping(struct dmu_mappings *m,
+ struct dmu_map *map)
+{
+ uint32_t bucket;
+ struct dmu_map *old;
+
+ down(&m->sem);
+
+ old = __dmu_find_mapping(m, map->org_block);
+ if (old)
+ __dmu_delete_mapping(m, old);
+
+ bucket = ((uint32_t)map->org_block) % m->size;
+
+ list_add(&map->list, &m->table[bucket]);
+ m->count++;
+
+ up(&m->sem);
+
+ return 1;
+}
+
+int dmu_map_from_mappings(struct dmu_device *dev,
+ struct bio *bio)
+{
+ struct dmu_map *map;
+ int ret = 0;
+
+ down(&dev->mappings->sem);
+
+ map = __dmu_find_mapping(dev->mappings,
+ dmu_block(dev, bio->bi_sector));
+
+ if (map && (bio_rw(bio) == map->rw)) {
+
+ bio->bi_sector = dmu_sector(dev, map->new_block) +
+ dmu_sector_offset(dev, bio->bi_sector) +
+ map->offset;
+ bio->bi_bdev = map->dest_dev;
+ ret = 1;
+ }
+
+ up(&dev->mappings->sem);
+
+ return ret;
+}
+
+int dmu_make_mapping(struct dmu_device *dev,
+ uint64_t org, uint64_t new, int64_t offset,
+ struct block_device *dest, int rw)
+{
+ struct dmu_map *map;
+
+ /* FIXME */
+ map = kmem_cache_alloc(map_cache, GFP_NOIO);
+ if (!map) {
+ DMERR("Failed to alloc mapping");
+ return 0;
+ }
+
+ INIT_LIST_HEAD(&map->list);
+
+ map->org_block = org;
+ map->new_block = new;
+ map->dest_dev = dest;
+ map->offset = offset;
+ map->rw = rw;
+
+ return dmu_add_mapping(dev->mappings, map);
+}
+
+int dmu_remove_mapping(struct dmu_device *dev,
+ uint64_t org)
+{
+ struct dmu_map *map;
+ int ret = 0;
+
+ down(&dev->mappings->sem);
+
+ map = __dmu_find_mapping(dev->mappings, org);
+ if (map) {
+ __dmu_delete_mapping(dev->mappings, map);
+ ret = 1;
+ }
+
+ up(&dev->mappings->sem);
+
+ return ret;
+}
+
+static unsigned int __destroy_bucket(struct dmu_mappings *m,
+ unsigned int index)
+{
+ struct dmu_map *map, *next;
+ unsigned int count = 0;
+
+ list_for_each_entry_safe(map, next, &m->table[index], list) {
+ __dmu_delete_mapping(m, map);
+ count++;
+ }
+
+ return count;
+}
+
+unsigned int dmu_remove_all_mappings(struct dmu_device *dev)
+{
+ int i;
+ unsigned int count = 0;
+
+ down(&dev->mappings->sem);
+
+ for (i = 0; i < dev->mappings->size; i++) {
+ count += __destroy_bucket(dev->mappings, i);
+ }
+
+ up(&dev->mappings->sem);
+
+ return count;
+}
+
+int dmu_init_mappings(void)
+{
+ map_cache =
+ kmem_cache_create("dm-userspace-mappings",
+ sizeof(struct dmu_map),
+ __alignof__ (struct dmu_map),
+ 0, NULL, NULL);
+ if (!map_cache) {
+ DMERR("Failed to allocate map cache");
+ return 0;
+ }
+
+ return 1;
+}
+
+void dmu_cleanup_mappings(void)
+{
+ kmem_cache_destroy(map_cache);
+}
+
+
diff -r 50f87a6ffd94 drivers/md/dm-userspace-chardev.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/md/dm-userspace-chardev.c Mon Jan 29 14:28:05 2007 -0800
@@ -0,0 +1,765 @@
+/*
+ * Copyright IBM 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;
+ int count = 0;
+ struct list_head *list = &dev->rx_requests[id % DMU_CP_HASH];
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->xmit_lock, flags);
+ list_for_each_entry_safe(req, next, list, list) {
+ count++;
+ if (req->id == id) {
+ list_del_init(&req->list);
+ match = req;
+ atomic_dec(&dev->r_reqs);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&dev->xmit_lock, flags);
+
+ 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);
+ schedule_work(&req->task);
+ }
+}
+
+static void add_rx_request(struct dmu_request *req)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&req->dev->xmit_lock, flags);
+ list_add_tail(&req->list,
+ &req->dev->rx_requests[req->id % DMU_CP_HASH]);
+ atomic_inc(&req->dev->r_reqs);
+ spin_unlock_irqrestore(&req->dev->xmit_lock, flags);
+}
+
+struct dmu_request *pluck_next_request(struct dmu_device *dev)
+{
+ struct dmu_request *req = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->xmit_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->xmit_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;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ring->r_lock, flags);
+ msg = dmu_head_msg(ring, ring->r_idx);
+ if (msg->hdr.status)
+ msg = NULL;
+ else
+ dmu_ring_idx_inc(ring);
+ spin_unlock_irqrestore(&ring->r_lock, flags);
+
+ 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->xmit_lock, flags);
+ list_add_tail(&req->list, &dev->tx_requests);
+ atomic_inc(&dev->t_reqs);
+ spin_unlock_irqrestore(&dev->xmit_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 void flush_block(int read_err, unsigned int write_err, void *data)
+{
+ struct dmu_request *req = data;
+
+ if (read_err || write_err) {
+ DMERR("Failed to copy block!");
+ bio_io_error(req->bio, req->bio->bi_size);
+ return;
+ }
+
+ atomic_inc(&req->dev->f_reqs);
+ generic_make_request(req->bio);
+}
+
+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);
+}
+
+static void map_worker(struct work_struct *work)
+{
+ struct dmu_request *req;
+ struct dmu_msg_map_response *msg;
+ struct dmu_device *dev;
+ struct target_device *src_dev, *dst_dev;
+
+ req = container_of(work, struct dmu_request, task);
+ msg = &req->response;
+ dev = req->dev;
+
+ if (dmu_get_flag(&msg->flags, DMU_FLAG_COPY_FIRST)) {
+ 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;
+ }
+
+ req->target_dev = dst_dev->bdev;
+
+ /* 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 (dmu_get_flag(&msg->flags, DMU_FLAG_COPY_FIRST))
+ 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_make_mapping(struct dmu_device *dev,
+ struct dmu_msg_make_mapping *msg)
+{
+ struct target_device *target;
+
+ target = find_target(dev, MKDEV(msg->dev_maj, msg->dev_min));
+ if (!target) {
+ DMERR("Failed to find target device %i:%i\n",
+ msg->dev_maj, msg->dev_min);
+ return;
+ }
+
+ dmu_make_mapping(dev,
+ msg->org_block, msg->new_block, msg->offset,
+ target->bdev, dmu_get_flag(&msg->flags, DMU_FLAG_WR));
+
+}
+
+static void do_kill_mapping(struct dmu_device *dev,
+ struct dmu_msg_make_mapping *msg)
+{
+ if (!dmu_remove_mapping(dev, msg->org_block))
+ DMERR("Tried to remove non-existent mapping for %llu",
+ msg->org_block);
+}
+
+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);
+ 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;
+
+ case DM_USERSPACE_MAKE_MAPPING:
+ do_make_mapping(dev, &msg->payload.make_mapping);
+ break;
+
+ case DM_USERSPACE_KILL_MAPPING:
+ do_kill_mapping(dev, &msg->payload.make_mapping);
+ 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);
+
+ /* Stop taking requests when there is no userspace to service them */
+ dev->request_slots = 0;
+
+ 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;
+ unsigned long flags;
+
+ poll_wait(file, &t->poll_wait, wait);
+
+ spin_lock_irqsave(&ring->r_lock, flags);
+
+ 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_irqrestore(&ring->r_lock, flags);
+
+ 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);
+
+ /* Open the gates and wake anyone waiting */
+ /* FIXME: Magic number */
+ dev->request_slots = 20000;
+ wake_up_interruptible(&dev->lowmem);
+
+ 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 -r 50f87a6ffd94 drivers/md/dm-userspace.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/md/dm-userspace.c Mon Jan 29 14:28:05 2007 -0800
@@ -0,0 +1,568 @@
+/*
+ * Copyright IBM 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"
+
+struct kmem_cache *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(struct work_struct *work)
+{
+ struct dmu_request *req;
+ struct dmu_device *dev;
+
+ req = container_of(work, struct dmu_request, task);
+ 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);
+ 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())
+ DMERR("%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;
+ int i;
+
+ 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);
+ }
+
+ for (i = 0; i < DMU_CP_HASH; i++) {
+ list_for_each_safe(cursor, next, &dev->rx_requests[i]) {
+ 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);
+ }
+ }
+
+ dmu_remove_all_mappings(dev);
+
+ 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, i;
+
+ 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->xmit_lock);
+
+ INIT_LIST_HEAD(&dev->tx_requests);
+
+ dev->rx_requests = kmalloc(sizeof(struct list_head) * DMU_CP_HASH,
+ GFP_KERNEL);
+ if (!dev->rx_requests) {
+ DMERR("Failed to alloc RX hash\n");
+ return 0;
+ }
+
+ for (i = 0; i < DMU_CP_HASH; i++)
+ INIT_LIST_HEAD(&dev->rx_requests[i]);
+
+ 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);
+
+ dmu_alloc_mappings(&dev->mappings, 2048);
+
+ ret = kcopyd_client_create(DMU_COPY_PAGES, &dev->kcopy);
+ if (ret) {
+ DMERR("Failed to initialize kcopyd client");
+ return 0;
+ }
+
+ dev->request_slots = 0; /* Unable to queue reqs right away */
+
+ 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))) {
+ DMINFO("Refusing bio barrier\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (dmu_map_from_mappings(dev, bio)) {
+ map_context->ptr = NULL;
+ return 1;
+ }
+
+ wait_event_interruptible(dev->lowmem,
+ atomic_read(&dev->total) <
+ dev->request_slots);
+
+ 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;
+
+ 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 (!req)
+ return 0;
+
+ 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);
+ 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 = dmu_init_mappings();
+ if (!r)
+ goto bad3;
+
+ r = init_chardev_transport();
+ if (!r)
+ goto bad4;
+
+ return 1;
+ bad4:
+ dmu_cleanup_mappings();
+ 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);
+
+ dmu_cleanup_mappings();
+
+ 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 -r 50f87a6ffd94 include/linux/dm-userspace.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/linux/dm-userspace.h Mon Jan 29 14:28:05 2007 -0800
@@ -0,0 +1,123 @@
+/*
+ * Copyright IBM Corp., 2006
+ * Author: Dan Smith <danms@xxxxxxxxxx>
+ *
+ * This file is released under the LGPL
+ *
+ */
+
+#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
+#define DM_USERSPACE_MAKE_MAPPING 6
+#define DM_USERSPACE_KILL_MAPPING 7
+
+/*
+ * 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;
+};
+
+struct dmu_msg_make_mapping {
+ uint64_t org_block;
+ uint64_t new_block;
+ int64_t offset;
+ uint32_t dev_maj;
+ uint32_t dev_min;
+ 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;
+ struct dmu_msg_make_mapping make_mapping;
+ } 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
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