[APPENDIX PATCH 1/5] blk_end_request: request-based dm core
From: Kiyoshi Ueda
Date: Fri Aug 31 2007 - 18:45:46 EST
This patch is an examle of block device stacking at request level,
showing the necessity of blk_end_request() and how the new
rq->end_io() hook is used.
Request-based dm itself is still under development and not ready
for inclusion.
This patch adds request-based dm feature to dm core.
Request-based dm hooks clone's ->end_io() to check errors of clone
returned from device drivers. (See clone_end_request())
# Currently, request-based dm can be turned on by ioctl at dm device
# creation time, so the userspace patches are needed.
# The ioctl from userspace is ignored if kernel doesn't support it,
# so please update userspace tools first when you try this.
# (If kernel was updated first, you would hit kernel panic.)
Signed-off-by: Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx>
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
---
block/ll_rw_blk.c | 9
drivers/md/dm-hw-handler.h | 1
drivers/md/dm-ioctl.c | 5
drivers/md/dm-table.c | 23 +
drivers/md/dm.c | 514 +++++++++++++++++++++++++++++++++++++++++- drivers/md/dm.h | 13 +
drivers/scsi/scsi_lib.c | 38 +++
include/linux/blkdev.h | 6
include/linux/device-mapper.h | 35 ++
include/linux/dm-ioctl.h | 9
10 files changed, 638 insertions(+), 15 deletions(-)
diff -rupN 07-change-end-io/block/ll_rw_blk.c a1-rqdm-core/block/ll_rw_blk.c
--- 07-change-end-io/block/ll_rw_blk.c 2007-08-24 12:31:41.000000000 -0400
+++ a1-rqdm-core/block/ll_rw_blk.c 2007-08-29 13:53:12.000000000 -0400
@@ -177,6 +177,13 @@ void blk_queue_softirq_done(struct reque
EXPORT_SYMBOL(blk_queue_softirq_done);
+void blk_queue_device_congested(struct request_queue *q, device_congested_fn *fn)
+{
+ q->device_congested_fn = fn;
+}
+
+EXPORT_SYMBOL_GPL(blk_queue_device_congested);
+
/**
* blk_queue_make_request - define an alternate make_request function for a device
* @q: the request queue for the device to be affected
@@ -3692,7 +3699,7 @@ int blk_end_io(struct request *rq, int u
struct request_queue *q = rq->q;
unsigned long flags = 0UL;
- if (blk_fs_request(rq) || blk_pc_request(rq)) {
+ if ((blk_fs_request(rq) || blk_pc_request(rq)) && !blk_cloned_rq(rq)) {
if (__end_that_request_first(rq, uptodate, nr_bytes))
return 1;
}
diff -rupN 07-change-end-io/drivers/md/dm.c a1-rqdm-core/drivers/md/dm.c
--- 07-change-end-io/drivers/md/dm.c 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/drivers/md/dm.c 2007-08-30 11:19:30.000000000 -0400
@@ -51,6 +51,22 @@ struct dm_target_io {
union map_info info;
};
+/*
+ * For request based dm.
+ * One of these is allocated per request.
+ *
+ * Since assuming "original request : cloned request = 1 : 1" and
+ * a counter for number of clones like struct dm_io.io_count isn't needed,
+ * struct dm_io and struct target_io can merge.
+ */
+struct dm_rq_target_io {
+ struct mapped_device *md;
+ int error;
+ struct request *rq;
+ struct dm_target *ti;
+ union map_info info;
+};
+
union map_info *dm_get_mapinfo(struct bio *bio)
{
if (bio && bio->bi_private)
@@ -58,6 +74,14 @@ union map_info *dm_get_mapinfo(struct bi
return NULL;
}
+union map_info *dm_get_rq_mapinfo(struct request *rq)
+{
+ if (rq && rq->end_io_data)
+ return &((struct dm_rq_target_io *)rq->end_io_data)->info;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
+
#define MINOR_ALLOCED ((void *)-1)
/*
@@ -70,6 +94,13 @@ union map_info *dm_get_mapinfo(struct bi
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
+/*
+ * Bits for the md->features field.
+ */
+#define DM_FEAT_REQUEST_BASE (1 << 0)
+
+#define dm_feat_rq_base(md) ((md)->features & DM_FEAT_REQUEST_BASE)
+
struct mapped_device {
struct rw_semaphore io_lock;
struct semaphore suspend_lock;
@@ -79,6 +110,7 @@ struct mapped_device {
atomic_t open_count;
unsigned long flags;
+ unsigned long features;
struct request_queue *queue;
struct gendisk *disk;
@@ -121,11 +153,16 @@ struct mapped_device {
/* forced geometry settings */
struct hd_geometry geometry;
+
+ /* For saving the address of __make_request for request based dm */
+ make_request_fn *saved_make_request_fn;
};
#define MIN_IOS 256
static struct kmem_cache *_io_cache;
static struct kmem_cache *_tio_cache;
+static struct kmem_cache *_rq_cache; /* clone pool for request-based dm */
+static struct kmem_cache *_rq_tio_cache; /* target_io pool for request-based dm */
static int __init local_init(void)
{
@@ -143,9 +180,27 @@ static int __init local_init(void)
return -ENOMEM;
}
+ _rq_cache = kmem_cache_create("dm_rq", sizeof(struct request),
+ 0, 0, NULL);
+ if (!_rq_cache) {
+ kmem_cache_destroy(_tio_cache);
+ kmem_cache_destroy(_io_cache);
+ return -ENOMEM;
+ }
+
+ _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
+ if (!_rq_tio_cache) {
+ kmem_cache_destroy(_rq_cache);
+ kmem_cache_destroy(_tio_cache);
+ kmem_cache_destroy(_io_cache);
+ return -ENOMEM;
+ }
+
_major = major;
r = register_blkdev(_major, _name);
if (r < 0) {
+ kmem_cache_destroy(_rq_tio_cache);
+ kmem_cache_destroy(_rq_cache);
kmem_cache_destroy(_tio_cache);
kmem_cache_destroy(_io_cache);
return r;
@@ -159,6 +214,8 @@ static int __init local_init(void)
static void local_exit(void)
{
+ kmem_cache_destroy(_rq_tio_cache);
+ kmem_cache_destroy(_rq_cache);
kmem_cache_destroy(_tio_cache);
kmem_cache_destroy(_io_cache);
unregister_blkdev(_major, _name);
@@ -341,6 +398,27 @@ static void free_tio(struct mapped_devic
mempool_free(tio, md->tio_pool);
}
+static inline struct request *alloc_rq(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_ATOMIC);
+}
+
+static inline void free_rq(struct mapped_device *md, struct request *rq)
+{
+ mempool_free(rq, md->io_pool);
+}
+
+static inline struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md)
+{
+ return mempool_alloc(md->tio_pool, GFP_ATOMIC);
+}
+
+static inline void free_rq_tio(struct mapped_device *md,
+ struct dm_rq_target_io *tio)
+{
+ mempool_free(tio, md->tio_pool);
+}
+
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
@@ -434,6 +512,93 @@ int dm_set_geometry(struct mapped_device
return 0;
}
+/*
+ * The queue is only valid as long as you have a reference
+ * count on 'md'.
+ */
+struct request_queue *dm_get_queue(struct mapped_device *md)
+{
+ if (blk_get_queue(md->queue))
+ return NULL;
+
+ return md->queue;
+}
+EXPORT_SYMBOL_GPL(dm_get_queue);
+
+void dm_put_queue(struct request_queue *q)
+{
+ blk_put_queue(q);
+}
+EXPORT_SYMBOL_GPL(dm_put_queue);
+
+void dm_stop_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_stop_queue);
+
+void dm_start_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (blk_queue_stopped(q))
+ blk_start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_start_queue);
+
+void __dm_requeue_request(struct request_queue *q, struct request *rq)
+{
+ if (elv_queue_empty(q))
+ blk_plug_device(q);
+ blk_requeue_request(q, rq);
+}
+EXPORT_SYMBOL_GPL(__dm_requeue_request);
+
+void dm_requeue_request(struct request_queue *q, struct request *rq)
+{
+ unsigned long flags = 0UL;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __dm_requeue_request(q, rq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_requeue_request);
+
+void dm_dispatch_request(struct request_queue *q, struct request *rq)
+{
+ int where = ELEVATOR_INSERT_BACK;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ /* Initialize statistic stuff */
+ disk_round_stats(rq->rq_disk);
+ rq->start_time = jiffies;
+ rq->rq_disk->in_flight++;
+
+ __elv_add_request(q, rq, where, 0);
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_dispatch_request);
+
+static void kill_request(struct request *rq)
+{
+ int nr_bytes = rq->hard_nr_sectors << 9;
+
+ if (!nr_bytes)
+ nr_bytes = rq->data_len;
+
+ rq->cmd_flags |= REQ_QUIET;
+ blk_end_request(rq, 0, nr_bytes);
+}
+
/*-----------------------------------------------------------------
* CRUD START:
* A more elegant soln is in the works that uses the queue
@@ -533,6 +698,152 @@ static int clone_endio(struct bio *bio,
return r;
}
+static void blk_update_cloned_rq(struct request *rq, struct request *clone)
+{
+ clone->nr_phys_segments = rq->nr_phys_segments;
+ clone->nr_hw_segments = rq->nr_hw_segments;
+ clone->current_nr_sectors = rq->current_nr_sectors;
+ clone->hard_cur_sectors = rq->hard_cur_sectors;
+ clone->hard_nr_sectors = rq->hard_nr_sectors;
+ clone->nr_sectors = rq->nr_sectors;
+ clone->hard_sector = rq->hard_sector;
+ clone->sector = rq->sector;
+ clone->data_len = rq->data_len;
+ clone->buffer = rq->buffer;
+ clone->data = rq->data;
+ clone->bio = rq->bio;
+ clone->biotail = rq->biotail;
+}
+
+static void dec_rq_pending(struct dm_rq_target_io *tio)
+{
+ if (!atomic_dec_return(&tio->md->pending))
+ /* nudge anyone waiting on suspend queue */
+ wake_up(&tio->md->wait);
+}
+
+static void finish_clone(struct request *clone, int needlock,
+ int (drv_callback)(struct request *))
+{
+ if (!clone->q)
+ /*
+ * The clone was not dispatched into underlying devices and
+ * it means the caller is not underlying device driver,
+ * the caller should be dm. (e.g. dispatch_queued_ios() of
+ * dm-multipath)
+ * So no need to do here for this clone.
+ */
+ return;
+
+ /*
+ * The clone is *NOT* freed actually here because it is alloced from
+ * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
+ *
+ * The uptodate and nr_bytes arguments of blk_end_io() don't matter
+ * because they aren't used for dm's clones.
+ */
+ if (blk_end_io(clone, 1, 0, needlock, NULL, drv_callback))
+ DMWARN("dm ignores the immediate return request of callback.");
+}
+
+static void clean_clone(struct request *clone)
+{
+ clone->special = NULL;
+ clone->errors = 0;
+}
+
+static int clone_end_request(struct request *clone, int uptodate, int nr_bytes,
+ int needlock, int (drv_callback)(struct request *))
+{
+ int r = 0, error = 0, rw = rq_data_dir(clone);
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ dm_request_endio_first_fn endio_first = tio->ti->type->rq_end_io_first;
+ dm_request_endio_fn endio = tio->ti->type->rq_end_io;
+ dm_request_queue_in_tgt_fn queue_in_tgt = tio->ti->type->queue_in_tgt;
+ struct request *orig = tio->rq;
+ struct request_queue *q = clone->q, *q_orig = orig->q;
+
+ if (blk_fs_request(clone) && clone->rq_disk)
+ disk_stat_add(clone->rq_disk, sectors[rw], nr_bytes >> 9);
+
+ if (end_io_error(uptodate))
+ error = !uptodate ? -EIO : uptodate;
+
+ if (endio_first) {
+ r = endio_first(tio->ti, clone, error, &tio->info);
+ switch (r) {
+ case 0:
+ /* succeeded */
+ break;
+ case 1:
+ /* the target wants to handle the io without unmap */
+ finish_clone(clone, needlock, drv_callback);
+ clean_clone(clone);
+
+ if (!queue_in_tgt) {
+ DMERR("queue_in_tgt isn't implemented.");
+ BUG();
+ }
+ queue_in_tgt(tio->ti, clone, &tio->info);
+ blk_run_queue(q_orig);
+
+ return 0;
+ case 2:
+ /* The target wants to requeue the original request */
+ if (needlock)
+ dm_requeue_request(q_orig, orig);
+ else
+ __dm_requeue_request(q_orig, orig);
+
+ goto free_clone;
+ default:
+ if (r >= 0) {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
+
+ /*
+ * the target detected error, but couldn't retry.
+ * direct the error to upper layer.
+ */
+ uptodate = r;
+ break;
+ }
+ }
+
+ /* Complete the original request's chunk */
+ r = blk_end_request(orig, uptodate, nr_bytes);
+
+ /*
+ * Recopy the original request fields that were updated
+ * in blk_end_request() to the clone.
+ */
+ blk_update_cloned_rq(orig, clone);
+
+ if (r)
+ /* The original request has leftover */
+ return 1;
+
+free_clone:
+ /*
+ * Now the original request is completed and freed, or requeued.
+ * So
+ */
+
+ if (endio)
+ endio(tio->ti, clone, error, &tio->info);
+
+ finish_clone(clone, needlock, drv_callback);
+
+ blk_run_queue(q_orig);
+
+ dec_rq_pending(tio);
+ free_rq(tio->md, clone);
+ free_rq_tio(tio->md, tio);
+
+ return 0;
+}
+
static sector_t max_io_len(struct mapped_device *md,
sector_t sector, struct dm_target *ti)
{
@@ -844,6 +1155,166 @@ static int dm_request(struct request_que
return 0;
}
+/* FIXME */
+static int dm_make_request(struct request_queue *q, struct bio *bio)
+{
+ int r = 0;
+ struct mapped_device *md = (struct mapped_device *)q->queuedata;
+
+ r = md->saved_make_request_fn(q, bio); /* call __make_request() */
+
+ return r;
+}
+
+static void setup_clone(struct request *clone, struct request *rq)
+{
+ INIT_LIST_HEAD(&clone->queuelist);
+ INIT_LIST_HEAD(&clone->donelist);
+ clone->q = NULL;
+ clone->cmd_flags = (rq_data_dir(rq) | REQ_NOMERGE | REQ_CLONED);
+ clone->cmd_type = rq->cmd_type;
+ clone->sector = rq->sector;
+ clone->hard_sector = rq->hard_sector;
+ clone->nr_sectors = rq->nr_sectors;
+ clone->hard_nr_sectors = rq->hard_nr_sectors;
+ clone->current_nr_sectors = rq->current_nr_sectors;
+ clone->hard_cur_sectors = rq->hard_cur_sectors;
+ clone->bio = rq->bio;
+ clone->biotail = rq->biotail;
+ INIT_HLIST_NODE(&clone->hash);
+// RB_CLEAR_NODE(&clone->rb_node);
+ clone->completion_data = NULL;
+ clone->elevator_private = NULL;
+ clone->elevator_private2 = NULL;
+ clone->rq_disk = NULL;
+ clone->start_time = jiffies;
+ clone->nr_phys_segments = rq->nr_phys_segments;
+ clone->nr_hw_segments = rq->nr_hw_segments;
+ clone->ioprio = rq->ioprio;
+ clone->special = NULL;
+ clone->buffer = rq->buffer;
+ clone->tag = -1;
+ clone->errors = 0;
+ clone->ref_count = 1;
+ clone->cmd_len = rq->cmd_len;
+ memcpy(clone->cmd, rq->cmd, sizeof(rq->cmd));
+ clone->data_len = rq->data_len;
+ clone->sense_len = rq->sense_len;
+ clone->data = rq->data;
+ clone->sense = rq->sense;
+ clone->timeout = 0;
+ clone->retries = 0;
+ clone->end_io = clone_end_request;
+ clone->end_io_data = NULL;
+}
+
+int dm_underlying_device_congested(struct request_queue *q)
+{
+ if (q->device_congested_fn)
+ return q->device_congested_fn(q);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_underlying_device_congested);
+
+static int clone_and_map_request(struct dm_target *ti, struct request *rq,
+ struct mapped_device *md)
+{
+ int r;
+ struct request *clone;
+ struct dm_rq_target_io *tio;
+
+ tio = alloc_rq_tio(md); /* only one for each original request */
+ if (!tio)
+ /* -ENOMEM */
+ goto requeue;
+ tio->md = md;
+ tio->error = 0;
+ tio->rq = rq;
+ tio->ti = ti;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ clone = alloc_rq(md);
+ if (!clone) {
+ /* -ENOMEM */
+ free_rq_tio(md, tio);
+ goto requeue;
+ }
+ setup_clone(clone, rq);
+ clone->end_io_data = tio;
+
+ atomic_inc(&md->pending);
+ r = ti->type->map_rq(ti, clone, &tio->info);
+ switch (r) {
+ case 0:
+ /* the target has taken the request to submit by itself */
+ break;
+ case 1:
+ /* the clone has been remapped so dispatch it */
+ dm_dispatch_request(clone->q, clone);
+ break;
+ case 2:
+ /* the target has requested to requeue the original request */
+ dec_rq_pending(tio);
+ free_rq_tio(md, tio);
+ free_rq(md, clone);
+ goto requeue;
+ default:
+ if (r >= 0) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
+
+ dec_rq_pending(tio);
+ free_rq_tio(md, tio);
+ free_rq(md, clone);
+ kill_request(rq);
+ break;
+ }
+
+ return 0;
+
+requeue:
+ return 1;
+}
+
+/*
+ * q->request_fn for request based dm.
+ * called with q->queue_lock held
+ */
+static void dm_request_fn(struct request_queue *q)
+{
+ int r;
+ struct mapped_device *md = (struct mapped_device *)q->queuedata;
+ struct dm_table *map = dm_get_table(md);
+ struct dm_target *ti;
+ dm_congested_fn congested;
+ struct request *rq;
+
+ while (!blk_queue_plugged(q)) {
+ rq = elv_next_request(q);
+ if (!rq)
+ break;
+
+ ti = dm_table_find_target(map, rq->sector);
+ congested = ti->type->congested;
+ if (congested && congested(ti))
+ break;
+
+ blkdev_dequeue_request(rq);
+ spin_unlock(q->queue_lock);
+ r = clone_and_map_request(ti, rq, md);
+ spin_lock_irq(q->queue_lock);
+
+ if (r)
+ __dm_requeue_request(q, rq);
+ }
+
+ dm_table_put(map);
+
+ return;
+}
+
static int dm_flush_all(struct request_queue *q, struct gendisk *disk,
sector_t *error_sector)
{
@@ -865,6 +1336,9 @@ static void dm_unplug_all(struct request
struct dm_table *map = dm_get_table(md);
if (map) {
+ if (dm_feat_rq_base(md))
+ generic_unplug_device(q);
+
dm_table_unplug_all(map);
dm_table_put(map);
}
@@ -966,7 +1440,7 @@ static struct block_device_operations dm
/*
* Allocate and initialise a blank device with a given minor.
*/
-static struct mapped_device *alloc_dev(int minor)
+static struct mapped_device *alloc_dev(int minor, int request_base)
{
int r;
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
@@ -997,23 +1471,35 @@ static struct mapped_device *alloc_dev(i
atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
- md->queue = blk_alloc_queue(GFP_KERNEL);
+ if (request_base) {
+ md->features |= DM_FEAT_REQUEST_BASE;
+ md->queue = blk_init_queue(dm_request_fn, NULL);
+ } else {
+ md->queue = blk_alloc_queue(GFP_KERNEL);
+ }
if (!md->queue)
goto bad1_free_minor;
md->queue->queuedata = md;
- md->queue->backing_dev_info.congested_fn = dm_any_congested;
- md->queue->backing_dev_info.congested_data = md;
- blk_queue_make_request(md->queue, dm_request);
+ if (request_base) {
+ md->saved_make_request_fn = md->queue->make_request_fn;
+ blk_queue_make_request(md->queue, dm_make_request);
+ } else {
+ md->queue->backing_dev_info.congested_fn = dm_any_congested;
+ md->queue->backing_dev_info.congested_data = md;
+ blk_queue_make_request(md->queue, dm_request);
+ }
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
md->queue->unplug_fn = dm_unplug_all;
md->queue->issue_flush_fn = dm_flush_all;
- md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
+ md->io_pool = mempool_create_slab_pool(MIN_IOS,
+ request_base ? _rq_cache : _io_cache);
if (!md->io_pool)
goto bad2;
- md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
+ md->tio_pool = mempool_create_slab_pool(MIN_IOS,
+ request_base ? _rq_tio_cache : _tio_cache);
if (!md->tio_pool)
goto bad3;
@@ -1154,11 +1640,12 @@ static void __unbind(struct mapped_devic
/*
* Constructor for a new device.
*/
-int dm_create(int minor, struct mapped_device **result)
+int dm_create(int minor, struct mapped_device **result, unsigned create_flags)
{
struct mapped_device *md;
+ int request_base = create_flags & DM_CREATE_REQUEST_BASE_FLAG ? 1 : 0;
- md = alloc_dev(minor);
+ md = alloc_dev(minor, request_base);
if (!md)
return -ENXIO;
@@ -1383,9 +1870,13 @@ int dm_suspend(struct mapped_device *md,
up_write(&md->io_lock);
/* unplug */
- if (map)
+ if (map) {
dm_table_unplug_all(map);
+ if (dm_feat_rq_base(md))
+ dm_stop_queue(md->queue);
+ }
+
/*
* Then we wait for the already mapped ios to
* complete.
@@ -1475,6 +1966,9 @@ int dm_resume(struct mapped_device *md)
if (!map || !dm_table_get_size(map))
goto out;
+ if (dm_feat_rq_base(md))
+ dm_start_queue(md->queue);
+
r = dm_table_resume_targets(map);
if (r)
goto out;
diff -rupN 07-change-end-io/drivers/md/dm.h a1-rqdm-core/drivers/md/dm.h
--- 07-change-end-io/drivers/md/dm.h 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/drivers/md/dm.h 2007-08-28 15:21:48.000000000 -0400
@@ -84,6 +84,11 @@
#define DM_SUSPEND_NOFLUSH_FLAG (1 << 1)
/*
+ * Create feature flags
+ */
+#define DM_CREATE_REQUEST_BASE_FLAG (1 << 0)
+
+/*
* List of devices that a metadevice uses and should open/close.
*/
struct dm_dev {
@@ -112,6 +117,7 @@ int dm_table_resume_targets(struct dm_ta
int dm_table_any_congested(struct dm_table *t, int bdi_bits);
void dm_table_unplug_all(struct dm_table *t);
int dm_table_flush_all(struct dm_table *t);
+int dm_table_underlying_device_congested(struct dm_table *t);
/*-----------------------------------------------------------------
* A registry of target types.
@@ -124,6 +130,12 @@ int dm_target_iterate(void (*iter_func)(
void *param), void *param);
/*-----------------------------------------------------------------
+ * Helper for block layer operations
+ *---------------------------------------------------------------*/
+void dm_dispatch_request(struct request_queue *q, struct request *rq);
+int dm_underlying_device_congested(struct request_queue *q);
+
+/*-----------------------------------------------------------------
* Useful inlines.
*---------------------------------------------------------------*/
static inline int array_too_big(unsigned long fixed, unsigned long obj,
@@ -180,6 +192,7 @@ void dm_stripe_exit(void);
void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
union map_info *dm_get_mapinfo(struct bio *bio);
+union map_info *dm_get_rq_mapinfo(struct request *rq);
int dm_open_count(struct mapped_device *md);
int dm_lock_for_deletion(struct mapped_device *md);
diff -rupN 07-change-end-io/drivers/md/dm-hw-handler.h a1-rqdm-core/drivers/md/dm-hw-handler.h
--- 07-change-end-io/drivers/md/dm-hw-handler.h 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/drivers/md/dm-hw-handler.h 2007-08-28 15:21:48.000000000 -0400
@@ -35,6 +35,7 @@ struct hw_handler_type {
void (*pg_init) (struct hw_handler *hwh, unsigned bypassed,
struct dm_path *path);
unsigned (*error) (struct hw_handler *hwh, struct bio *bio);
+ unsigned (*error_rq) (struct hw_handler *hwh, struct request *rq);
int (*status) (struct hw_handler *hwh, status_type_t type,
char *result, unsigned int maxlen);
};
diff -rupN 07-change-end-io/drivers/md/dm-ioctl.c a1-rqdm-core/drivers/md/dm-ioctl.c
--- 07-change-end-io/drivers/md/dm-ioctl.c 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/drivers/md/dm-ioctl.c 2007-08-28 15:21:48.000000000 -0400
@@ -565,6 +565,7 @@ static int dev_create(struct dm_ioctl *p
{
int r, m = DM_ANY_MINOR;
struct mapped_device *md;
+ unsigned create_flags = 0;
r = check_name(param->name);
if (r)
@@ -572,8 +573,10 @@ static int dev_create(struct dm_ioctl *p
if (param->flags & DM_PERSISTENT_DEV_FLAG)
m = MINOR(huge_decode_dev(param->dev));
+ if (param->flags & DM_REQUEST_BASE_FLAG)
+ create_flags |= DM_CREATE_REQUEST_BASE_FLAG;
- r = dm_create(m, &md);
+ r = dm_create(m, &md, create_flags);
if (r)
return r;
diff -rupN 07-change-end-io/drivers/md/dm-table.c a1-rqdm-core/drivers/md/dm-table.c
--- 07-change-end-io/drivers/md/dm-table.c 2007-08-22 18:54:04.000000000 -0400
+++ a1-rqdm-core/drivers/md/dm-table.c 2007-08-28 15:21:48.000000000 -0400
@@ -1025,6 +1025,29 @@ int dm_table_flush_all(struct dm_table *
return ret;
}
+int dm_table_underlying_device_congested(struct dm_table *t)
+{
+ int r = 0;
+ struct list_head *d, *devices = dm_table_get_devices(t);
+ struct dm_dev *dd;
+ struct request_queue *q;
+
+ for (d = devices->next; d != devices; d = d->next) {
+ dd = list_entry(d, struct dm_dev, list);
+ q = bdev_get_queue(dd->bdev);
+
+ /*
+ * We should use "&=" and target driver should chose
+ * not congested device by using a table function like
+ * dm_table_uncongested_device().
+ */
+ r &= dm_underlying_device_congested(q);
+// r |= dm_underlying_device_congested(q);
+ }
+
+ return r;
+}
+
struct mapped_device *dm_table_get_md(struct dm_table *t)
{
dm_get(t->md);
diff -rupN 07-change-end-io/drivers/scsi/scsi_lib.c a1-rqdm-core/drivers/scsi/scsi_lib.c
--- 07-change-end-io/drivers/scsi/scsi_lib.c 2007-08-24 12:26:06.000000000 -0400
+++ a1-rqdm-core/drivers/scsi/scsi_lib.c 2007-08-28 15:21:48.000000000 -0400
@@ -1401,6 +1401,43 @@ static void scsi_softirq_done(struct req
}
}
+static int scsi_device_congested(struct request_queue *q)
+{
+ int r = 0;
+ struct scsi_device *sdev = q->queuedata;
+// struct Scsi_Host *shost;
+// unsigned long flags = 0UL;
+
+ if (!sdev || !get_device(&sdev->sdev_gendev))
+ /*
+ * Something may happened. We handle it in scsi_request_fn.
+ * Please dispatch the requests in the queue.
+ */
+ return 0;
+
+ if ((sdev->device_busy >= sdev->queue_depth) || sdev->device_blocked ||
+ (sdev->single_lun && scsi_target(sdev)->starget_sdev_user &&
+ scsi_target(sdev)->starget_sdev_user != sdev)) {
+ r = 1;
+ goto out;
+ }
+
+/*
+ shost = sdev->host;
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_in_recovery(shost) ||
+ (shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
+ shost->host_blocked || shost->host_self_blocked)
+ r = 1;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+*/
+
+out:
+ put_device(&sdev->sdev_gendev);
+
+ return r;
+}
+
/*
* Function: scsi_request_fn()
*
@@ -1590,6 +1627,7 @@ struct request_queue *scsi_alloc_queue(s
blk_queue_prep_rq(q, scsi_prep_fn);
blk_queue_softirq_done(q, scsi_softirq_done);
+ blk_queue_device_congested(q, scsi_device_congested);
return q;
}
diff -rupN 07-change-end-io/include/linux/blkdev.h a1-rqdm-core/include/linux/blkdev.h
--- 07-change-end-io/include/linux/blkdev.h 2007-08-24 12:32:44.000000000 -0400
+++ a1-rqdm-core/include/linux/blkdev.h 2007-08-29 13:53:12.000000000 -0400
@@ -203,6 +203,7 @@ enum rq_flag_bits {
__REQ_RW_SYNC, /* request is sync (O_DIRECT) */
__REQ_ALLOCED, /* request came from our alloc pool */
__REQ_RW_META, /* metadata io request */
+ __REQ_CLONED, /* request is a clone of another request */
__REQ_NR_BITS, /* stops here */
};
@@ -224,6 +225,7 @@ enum rq_flag_bits {
#define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
#define REQ_ALLOCED (1 << __REQ_ALLOCED)
#define REQ_RW_META (1 << __REQ_RW_META)
+#define REQ_CLONED (1 << __REQ_CLONED)
#define BLK_MAX_CDB 16
@@ -348,6 +350,7 @@ typedef int (merge_bvec_fn) (struct requ
typedef int (issue_flush_fn) (struct request_queue *, struct gendisk *, sector_t *);
typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
typedef void (softirq_done_fn)(struct request *);
+typedef int (device_congested_fn) (struct request_queue *q);
enum blk_queue_state {
Queue_down,
@@ -386,6 +389,7 @@ struct request_queue
issue_flush_fn *issue_flush_fn;
prepare_flush_fn *prepare_flush_fn;
softirq_done_fn *softirq_done_fn;
+ device_congested_fn *device_congested_fn;
/*
* Dispatch queue sorting
@@ -555,6 +559,7 @@ enum {
#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
+#define blk_cloned_rq(rq) ((rq)->cmd_flags & REQ_CLONED)
#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
@@ -786,6 +791,7 @@ extern void blk_queue_prep_rq(struct req
extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
extern void blk_queue_dma_alignment(struct request_queue *, int);
extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
+extern void blk_queue_device_congested(struct request_queue *, device_congested_fn *);
extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
extern void blk_queue_issue_flush_fn(struct request_queue *, issue_flush_fn *);
diff -rupN 07-change-end-io/include/linux/device-mapper.h a1-rqdm-core/include/linux/device-mapper.h
--- 07-change-end-io/include/linux/device-mapper.h 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/include/linux/device-mapper.h 2007-08-28 15:21:48.000000000 -0400
@@ -10,6 +10,8 @@
#ifdef __KERNEL__
+struct request;
+struct request_queue;
struct dm_target;
struct dm_table;
struct dm_dev;
@@ -45,6 +47,9 @@ typedef void (*dm_dtr_fn) (struct dm_tar
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
+typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
+ union map_info *map_context);
+
/*
* Returns:
* < 0 : error (currently ignored)
@@ -57,6 +62,18 @@ typedef int (*dm_endio_fn) (struct dm_ta
struct bio *bio, int error,
union map_info *map_context);
+typedef int (*dm_request_endio_first_fn) (struct dm_target *ti,
+ struct request *clone, int error,
+ union map_info *map_context);
+
+typedef int (*dm_request_endio_fn) (struct dm_target *ti,
+ struct request *clone, int error,
+ union map_info *map_context);
+
+typedef void (*dm_request_queue_in_tgt_fn) (struct dm_target *ti,
+ struct request *clone,
+ union map_info *map_context);
+
typedef void (*dm_flush_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
@@ -71,6 +88,7 @@ typedef int (*dm_message_fn) (struct dm_
typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
struct file *filp, unsigned int cmd,
unsigned long arg);
+typedef int (*dm_congested_fn) (struct dm_target *ti);
void dm_error(const char *message);
@@ -98,7 +116,11 @@ struct target_type {
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
+ dm_map_request_fn map_rq;
dm_endio_fn end_io;
+ dm_request_endio_first_fn rq_end_io_first;
+ dm_request_endio_fn rq_end_io;
+ dm_request_queue_in_tgt_fn queue_in_tgt;
dm_flush_fn flush;
dm_presuspend_fn presuspend;
dm_postsuspend_fn postsuspend;
@@ -107,6 +129,7 @@ struct target_type {
dm_status_fn status;
dm_message_fn message;
dm_ioctl_fn ioctl;
+ dm_congested_fn congested;
};
struct io_restrictions {
@@ -142,6 +165,8 @@ struct dm_target {
/* Used to provide an error string from the ctr */
char *error;
+
+ struct request_queue *queue;
};
int dm_register_target(struct target_type *t);
@@ -157,7 +182,7 @@ int dm_unregister_target(struct target_t
* DM_ANY_MINOR chooses the next available minor number.
*/
#define DM_ANY_MINOR (-1)
-int dm_create(int minor, struct mapped_device **md);
+int dm_create(int minor, struct mapped_device **md, unsigned create_flags);
/*
* Reference counting for md.
@@ -167,6 +192,14 @@ void dm_get(struct mapped_device *md);
void dm_put(struct mapped_device *md);
/*
+ * Queue operations
+ */
+struct request_queue *dm_get_queue(struct mapped_device *md);
+void dm_put_queue(struct request_queue *q);
+void dm_stop_queue(struct request_queue *q);
+void dm_start_queue(struct request_queue *q);
+
+/*
* An arbitrary pointer may be stored alongside a mapped device.
*/
void dm_set_mdptr(struct mapped_device *md, void *ptr);
diff -rupN 07-change-end-io/include/linux/dm-ioctl.h a1-rqdm-core/include/linux/dm-ioctl.h
--- 07-change-end-io/include/linux/dm-ioctl.h 2007-08-13 00:25:24.000000000 -0400
+++ a1-rqdm-core/include/linux/dm-ioctl.h 2007-08-28 15:21:48.000000000 -0400
@@ -285,9 +285,9 @@ typedef char ioctl_struct[308];
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 11
+#define DM_VERSION_MINOR 12
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2006-10-12)"
+#define DM_VERSION_EXTRA "-ioctl (2006-12-14)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
@@ -328,4 +328,9 @@ typedef char ioctl_struct[308];
*/
#define DM_NOFLUSH_FLAG (1 << 11) /* In */
+/*
+ * Set this to create request based device-mapper device.
+ */
+#define DM_REQUEST_BASE_FLAG (1 << 12) /* In */
+
#endif /* _LINUX_DM_IOCTL_H */
-
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