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dm: move deferred bio flushing to workqueue

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Add a single-thread workqueue for each mapped device
and move flushing of the lists of pushback and deferred bios
to this new workqueue.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz 2008-02-08 02:11:17 +00:00 committed by Alasdair G Kergon
parent 3a7f6c990a
commit 304f3f6a58
1 changed files with 67 additions and 12 deletions
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79
drivers/md/dm.c
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@ -71,6 +71,19 @@ union map_info *dm_get_mapinfo(struct bio *bio)
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
/*
* Work processed by per-device workqueue.
*/
struct dm_wq_req {
enum {
DM_WQ_FLUSH_ALL,
DM_WQ_FLUSH_DEFERRED,
} type;
struct work_struct work;
struct mapped_device *md;
void *context;
};
struct mapped_device {
struct rw_semaphore io_lock;
struct mutex suspend_lock;
@ -95,6 +108,11 @@ struct mapped_device {
struct bio_list deferred;
struct bio_list pushback;
/*
* Processing queue (flush/barriers)
*/
struct workqueue_struct *wq;
/*
* The current mapping.
*/
@ -1044,6 +1062,10 @@ static struct mapped_device *alloc_dev(int minor)
add_disk(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = create_singlethread_workqueue("kdmflush");
if (!md->wq)
goto bad_thread;
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
@ -1053,6 +1075,8 @@ static struct mapped_device *alloc_dev(int minor)
return md;
bad_thread:
put_disk(md->disk);
bad_disk:
bioset_free(md->bs);
bad_no_bioset:
@ -1080,6 +1104,7 @@ static void free_dev(struct mapped_device *md)
unlock_fs(md);
bdput(md->suspended_bdev);
}
destroy_workqueue(md->wq);
mempool_destroy(md->tio_pool);
mempool_destroy(md->io_pool);
bioset_free(md->bs);
@ -1308,6 +1333,44 @@ static void __merge_pushback_list(struct mapped_device *md)
spin_unlock_irqrestore(&md->pushback_lock, flags);
}
static void dm_wq_work(struct work_struct *work)
{
struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
struct mapped_device *md = req->md;
down_write(&md->io_lock);
switch (req->type) {
case DM_WQ_FLUSH_ALL:
__merge_pushback_list(md);
/* pass through */
case DM_WQ_FLUSH_DEFERRED:
__flush_deferred_io(md);
break;
default:
DMERR("dm_wq_work: unrecognised work type %d", req->type);
BUG();
}
up_write(&md->io_lock);
}
static void dm_wq_queue(struct mapped_device *md, int type, void *context,
struct dm_wq_req *req)
{
req->type = type;
req->md = md;
req->context = context;
INIT_WORK(&req->work, dm_wq_work);
queue_work(md->wq, &req->work);
}
static void dm_queue_flush(struct mapped_device *md, int type, void *context)
{
struct dm_wq_req req;
dm_wq_queue(md, type, context, &req);
flush_workqueue(md->wq);
}
/*
* Swap in a new table (destroying old one).
*/
@ -1450,9 +1513,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
/* were we interrupted ? */
if (r < 0) {
down_write(&md->io_lock);
__flush_deferred_io(md);
up_write(&md->io_lock);
dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
@ -1463,16 +1524,12 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
set_bit(DMF_SUSPENDED, &md->flags);
flush_and_out:
if (r && noflush) {
if (r && noflush)
/*
* Because there may be already I/Os in the pushback list,
* flush them before return.
*/
down_write(&md->io_lock);
__merge_pushback_list(md);
__flush_deferred_io(md);
up_write(&md->io_lock);
}
dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
out:
if (r && md->suspended_bdev) {
@ -1504,9 +1561,7 @@ int dm_resume(struct mapped_device *md)
if (r)
goto out;
down_write(&md->io_lock);
__flush_deferred_io(md);
up_write(&md->io_lock);
dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
unlock_fs(md);