From 9bf59a611a5eb479f321fae34adc9f948de0a42f Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Fri, 28 Feb 2014 15:33:48 +0100
Subject: [PATCH] dm mpath: remove extra nesting in map function
Return early for case when no path exists, and when the
pathgroup isn't ready. This eliminates the need for
extra nesting for the the common case.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/md/dm-mpath.c | 46 ++++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 07ca77f2943800..e7d80baf8d69ce 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -398,29 +398,31 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
pgpath = m->current_pgpath;
- if (pgpath) {
- if (pg_ready(m)) {
- if (set_mapinfo(m, map_context) < 0)
- /* 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;
- if (pgpath->pg->ps.type->start_io)
- pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
- &pgpath->path,
- nr_bytes);
- r = DM_MAPIO_REMAPPED;
- goto out_unlock;
- }
+ if (!pgpath) {
+ if (!__must_push_back(m))
+ r = -EIO; /* Failed */
+ goto out_unlock;
+ }
+ if (!pg_ready(m)) {
__pg_init_all_paths(m);
- } else if (!__must_push_back(m))
- r = -EIO; /* Failed */
+ goto out_unlock;
+ }
+ if (set_mapinfo(m, map_context) < 0)
+ /* 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;
+ if (pgpath->pg->ps.type->start_io)
+ pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
+ &pgpath->path,
+ nr_bytes);
+ r = DM_MAPIO_REMAPPED;
out_unlock:
spin_unlock_irqrestore(&m->lock, flags);
--
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