metadata_wq serves on-stack work items from chunk_io(). Even if
multiple chunk_io() are simultaneously in progress, each is
independent and queued only once, so multithreaded workqueue can be
safely used.
Switch metadata_wq to multithread and flush the work item instead of
the workqueue in chunk_io().
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: dm-devel@xxxxxxxxxx
---
drivers/md/dm-snap-persistent.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index d3021a6..95891df 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -256,7 +256,7 @@ static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw,
*/
INIT_WORK_ONSTACK(&req.work, do_metadata);
queue_work(ps->metadata_wq, &req.work);
- flush_workqueue(ps->metadata_wq);
+ flush_work(&req.work);
return req.result;
}
@@ -818,7 +818,7 @@ static int persistent_ctr(struct dm_exception_store *store,
atomic_set(&ps->pending_count, 0);
ps->callbacks = NULL;
- ps->metadata_wq = alloc_ordered_workqueue("ksnaphd", WQ_MEM_RECLAIM);
+ ps->metadata_wq = alloc_workqueue("ksnaphd", WQ_MEM_RECLAIM, 0);
if (!ps->metadata_wq) {
kfree(ps);
DMERR("couldn't start header metadata update thread");
--
1.7.1
--
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