dm: submit stacked requests in irq enabled context
Switch to having request-based DM enqueue all prep'ed requests into work
processed by another thread. This allows request-based DM to invoke
block APIs that assume interrupt enabled context (e.g. blk_get_request)
and is a prerequisite for adding blk-mq support to request-based DM.
The new kernel thread is only initialized for request-based DM devices.
multipath_map() is now always in irq enabled context so change multipath
spinlock (m->lock) locking to always disable interrupts.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 7b6b0f0..2552b88 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -384,12 +384,11 @@
struct multipath *m = (struct multipath *) ti->private;
int r = DM_MAPIO_REQUEUE;
size_t nr_bytes = blk_rq_bytes(clone);
- unsigned long flags;
struct pgpath *pgpath;
struct block_device *bdev;
struct dm_mpath_io *mpio;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
/* Do we need to select a new pgpath? */
if (!m->current_pgpath ||
@@ -411,21 +410,26 @@
/* ENOMEM, requeue */
goto out_unlock;
- bdev = pgpath->path.dev->bdev;
- clone->q = bdev_get_queue(bdev);
- clone->rq_disk = bdev->bd_disk;
- clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
mpio = map_context->ptr;
mpio->pgpath = pgpath;
mpio->nr_bytes = nr_bytes;
+
+ bdev = pgpath->path.dev->bdev;
+
+ clone->q = bdev_get_queue(bdev);
+ clone->rq_disk = bdev->bd_disk;
+ clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
+
+ spin_unlock_irq(&m->lock);
+
if (pgpath->pg->ps.type->start_io)
pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
&pgpath->path,
nr_bytes);
- r = DM_MAPIO_REMAPPED;
+ return DM_MAPIO_REMAPPED;
out_unlock:
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
return r;
}