bcache/md: Use raid stripe size

Now that we've got code for raid5/6 stripe awareness, bcache just needs
to know about the stripes and when writing partial stripes is expensive
- we probably don't want to enable this optimization for raid1 or 10,
even though they have stripes. So add a flag to queue_limits.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 05e826793e4e..5d21239bc859 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -592,6 +592,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                 ret = -1;
         }
 
+        t->raid_partial_stripes_expensive =
+                max(t->raid_partial_stripes_expensive,
+                    b->raid_partial_stripes_expensive);
+
         /* Find lowest common alignment_offset */
         t->alignment_offset = lcm(t->alignment_offset, alignment)
                 & (max(t->physical_block_size, t->io_min) - 1);