[dm-devel] [RFC PATCH 10/13] dm: enable request-based dm
Kiyoshi Ueda
k-ueda at ct.jp.nec.com
Wed Mar 19 23:11:14 UTC 2008
This patch enables request-based dm.
Request-based dm and bio-based dm coexist, since there are
some target drivers which are more fitting to bio-based dm.
There are some limitations between them.
- OK: bio-based dm device on bio-based dm device
- OK: bio-based dm device on request-based dm device
- OK: request-based dm device on request-based dm device
- NG: request-based dm device on bio-based dm device
The type of a dm device is decided at the first table loading time.
Until then, mempool creations and queue initializations are deferred.
Once the type of a dm device is decided, the type can't be changed.
Signed-off-by: Kiyoshi Ueda <k-ueda at ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura at ce.jp.nec.com>
---
drivers/md/dm-table.c | 54 +++++++++++++++
drivers/md/dm.c | 174 +++++++++++++++++++++++++++++++++++++++-----------
drivers/md/dm.h | 6 +
3 files changed, 199 insertions(+), 35 deletions(-)
Index: 2.6.25-rc5/drivers/md/dm-table.c
===================================================================
--- 2.6.25-rc5.orig/drivers/md/dm-table.c
+++ 2.6.25-rc5/drivers/md/dm-table.c
@@ -813,6 +813,55 @@ static int setup_indexes(struct dm_table
return 0;
}
+#define DM_HOOK_AT_REQUEST 0
+#define DM_HOOK_AT_BIO 1
+
+/*
+ * Check the consistency of targets' hook type
+ *
+ * Returns
+ * DM_HOOK_AT_REQUEST: the table is for request-based dm
+ * DM_HOOK_AT_BIO : the table is for bio-based dm
+ * negative : the table is not consistent
+ */
+static int check_table_hook_type(struct dm_table *t)
+{
+ unsigned int i;
+ unsigned int bio_based = 0, rq_based = 0;
+ struct dm_target *ti;
+
+ for (i = 0; i < t->num_targets; i++) {
+ ti = t->targets + i;
+
+ if (ti->type->map_rq)
+ rq_based = 1;
+ else
+ bio_based = 1;
+
+ if (rq_based && bio_based) {
+ DMERR("Inconsistent table: different target types"
+ " mixed up");
+ return -EINVAL;
+ }
+ }
+
+ return rq_based ? DM_HOOK_AT_REQUEST : DM_HOOK_AT_BIO;
+}
+
+static int set_md_hook_type(struct dm_table *t)
+{
+ int r = check_table_hook_type(t);
+
+ switch (r) {
+ case DM_HOOK_AT_REQUEST:
+ return dm_set_md_request_based(t->md);
+ case DM_HOOK_AT_BIO:
+ return dm_set_md_bio_based(t->md);
+ default:
+ return r;
+ }
+}
+
/*
* Builds the btree to index the map.
*/
@@ -821,6 +870,11 @@ int dm_table_complete(struct dm_table *t
int r = 0;
unsigned int leaf_nodes;
+ /* Setup the mapped_device to bio-based dm or request-based dm */
+ r = set_md_hook_type(t);
+ if (r)
+ return r;
+
check_for_valid_limits(&t->limits);
/* how many indexes will the btree have ? */
Index: 2.6.25-rc5/drivers/md/dm.c
===================================================================
--- 2.6.25-rc5.orig/drivers/md/dm.c
+++ 2.6.25-rc5/drivers/md/dm.c
@@ -100,6 +100,7 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_REQUEST_BASED 6
+#define DMF_BIO_BASED 7
/*
* Work processed by per-device workqueue.
@@ -1507,6 +1508,135 @@ out:
return r;
}
+static void init_queue(struct request_queue *q, struct mapped_device *md)
+{
+ q->queuedata = md;
+ q->backing_dev_info.congested_fn = dm_any_congested;
+ q->backing_dev_info.congested_data = md;
+ blk_queue_make_request(q, dm_request);
+ blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
+ q->unplug_fn = dm_unplug_all;
+}
+
+int dm_set_md_request_based(struct mapped_device *md)
+{
+ int r = 0;
+
+ if (test_bit(DMF_REQUEST_BASED, &md->flags))
+ /* Initialization is already done */
+ return 0;
+
+ if (test_bit(DMF_BIO_BASED, &md->flags)) {
+ DMERR("Can't change hook type to request-based from bio-based");
+ return -EINVAL;
+ }
+
+ md->io_pool = mempool_create_slab_pool(MIN_IOS, _bio_info_cache);
+ if (!md->io_pool)
+ return -ENOMEM;
+
+ md->tio_pool = mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
+ if (!md->tio_pool) {
+ r = -ENOMEM;
+ goto out_free_io_pool;
+ }
+
+ md->bs = bioset_create(MIN_IOS, MIN_IOS);
+ if (!md->bs) {
+ r = -ENOMEM;
+ goto out_free_tio_pool;
+ }
+
+ md->queue = blk_init_queue(dm_request_fn, NULL);
+ if (!md->queue) {
+ DMERR("request queue initialization for request-based failed");
+ r = -ENOMEM;
+ goto out_free_bs;
+ }
+
+ md->saved_make_request_fn = md->queue->make_request_fn;
+ init_queue(md->queue, md);
+ blk_queue_softirq_done(md->queue, dm_softirq_done);
+ md->disk->queue = md->queue;
+ r = blk_register_queue(md->disk);
+ if (r) {
+ DMERR("registration of request queue failed");
+ goto out_cleanup_queue;
+ }
+
+ set_bit(DMF_REQUEST_BASED, &md->flags);
+
+ return 0;
+
+out_cleanup_queue:
+ blk_cleanup_queue(md->queue);
+ md->disk->queue = md->queue = NULL;
+ md->saved_make_request_fn = NULL;
+
+out_free_bs:
+ bioset_free(md->bs);
+ md->bs = NULL;
+
+out_free_tio_pool:
+ mempool_destroy(md->tio_pool);
+ md->tio_pool = NULL;
+
+out_free_io_pool:
+ mempool_destroy(md->io_pool);
+ md->io_pool = NULL;
+
+ return r;
+}
+
+int dm_set_md_bio_based(struct mapped_device *md)
+{
+ if (test_bit(DMF_BIO_BASED, &md->flags))
+ /* Initialization is already done */
+ return 0;
+
+ if (test_bit(DMF_REQUEST_BASED, &md->flags)) {
+ DMERR("Can't change hook type to bio-based from request-based");
+ return -EINVAL;
+ }
+
+ md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
+ if (!md->io_pool)
+ goto out;
+
+ md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
+ if (!md->tio_pool)
+ goto out_free_io_pool;
+
+ md->bs = bioset_create(16, 16);
+ if (!md->bs)
+ goto out_free_tio_pool;
+
+ md->queue = blk_alloc_queue(GFP_KERNEL);
+ if (!md->queue) {
+ DMERR("request queue initialization for request-based failed");
+ goto out_free_bs;
+ }
+
+ init_queue(md->queue, md);
+ md->disk->queue = md->queue;
+
+ set_bit(DMF_BIO_BASED, &md->flags);
+
+ return 0;
+
+out_free_bs:
+ bioset_free(md->bs);
+ md->bs = NULL;
+out_free_tio_pool:
+ mempool_destroy(md->tio_pool);
+ md->tio_pool = NULL;
+out_free_io_pool:
+ mempool_destroy(md->io_pool);
+ md->io_pool = NULL;
+out:
+ return -ENOMEM;
+}
+
static struct block_device_operations dm_blk_dops;
/*
@@ -1546,28 +1676,7 @@ static struct mapped_device *alloc_dev(i
INIT_LIST_HEAD(&md->uevent_list);
spin_lock_init(&md->uevent_lock);
- md->queue = blk_alloc_queue(GFP_KERNEL);
- if (!md->queue)
- goto bad_queue;
-
- 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);
- blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
- md->queue->unplug_fn = dm_unplug_all;
-
- md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
- if (!md->io_pool)
- goto bad_io_pool;
-
- md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
- if (!md->tio_pool)
- goto bad_tio_pool;
-
- md->bs = bioset_create(16, 16);
- if (!md->bs)
- goto bad_no_bioset;
+ /* md's queue and mempools will be allocated after the 1st table load */
md->disk = alloc_disk(1);
if (!md->disk)
@@ -1580,7 +1689,6 @@ static struct mapped_device *alloc_dev(i
md->disk->major = _major;
md->disk->first_minor = minor;
md->disk->fops = &dm_blk_dops;
- md->disk->queue = md->queue;
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
add_disk(md->disk);
@@ -1602,14 +1710,6 @@ static struct mapped_device *alloc_dev(i
bad_thread:
put_disk(md->disk);
bad_disk:
- bioset_free(md->bs);
-bad_no_bioset:
- mempool_destroy(md->tio_pool);
-bad_tio_pool:
- mempool_destroy(md->io_pool);
-bad_io_pool:
- blk_cleanup_queue(md->queue);
-bad_queue:
free_minor(minor);
bad_minor:
module_put(THIS_MODULE);
@@ -1629,9 +1729,12 @@ static void free_dev(struct mapped_devic
bdput(md->suspended_bdev);
}
destroy_workqueue(md->wq);
- mempool_destroy(md->tio_pool);
- mempool_destroy(md->io_pool);
- bioset_free(md->bs);
+ if (md->tio_pool)
+ mempool_destroy(md->tio_pool);
+ if (md->io_pool)
+ mempool_destroy(md->io_pool);
+ if (md->bs)
+ bioset_free(md->bs);
del_gendisk(md->disk);
free_minor(minor);
@@ -1640,7 +1743,8 @@ static void free_dev(struct mapped_devic
spin_unlock(&_minor_lock);
put_disk(md->disk);
- blk_cleanup_queue(md->queue);
+ if (md->queue)
+ blk_cleanup_queue(md->queue);
module_put(THIS_MODULE);
kfree(md);
}
Index: 2.6.25-rc5/drivers/md/dm.h
===================================================================
--- 2.6.25-rc5.orig/drivers/md/dm.h
+++ 2.6.25-rc5/drivers/md/dm.h
@@ -197,4 +197,10 @@ int dm_lock_for_deletion(struct mapped_d
void dm_kobject_uevent(struct mapped_device *md);
+/*
+ * Initializer for request-based/bio-based device
+ */
+int dm_set_md_request_based(struct mapped_device *md);
+int dm_set_md_bio_based(struct mapped_device *md);
+
#endif
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