dm: remove limited barrier support
Prepare for full barrier implementation: first remove the restricted support.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index bfa107f..79fb53e 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -142,7 +142,6 @@
.status = linear_status,
.ioctl = linear_ioctl,
.merge = linear_merge,
- .features = DM_TARGET_SUPPORTS_BARRIERS,
};
int __init dm_linear_init(void)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 02d0b48..429b50b 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -52,8 +52,6 @@
sector_t *highs;
struct dm_target *targets;
- unsigned barriers_supported:1;
-
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
@@ -243,7 +241,6 @@
INIT_LIST_HEAD(&t->devices);
atomic_set(&t->holders, 0);
- t->barriers_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -751,10 +748,6 @@
/* FIXME: the plan is to combine high here and then have
* the merge fn apply the target level restrictions. */
combine_restrictions_low(&t->limits, &tgt->limits);
-
- if (!(tgt->type->features & DM_TARGET_SUPPORTS_BARRIERS))
- t->barriers_supported = 0;
-
return 0;
bad:
@@ -799,12 +792,6 @@
check_for_valid_limits(&t->limits);
- /*
- * We only support barriers if there is exactly one underlying device.
- */
- if (!list_is_singular(&t->devices))
- t->barriers_supported = 0;
-
/* how many indexes will the btree have ? */
leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
@@ -1059,12 +1046,6 @@
return t->md;
}
-int dm_table_barrier_ok(struct dm_table *t)
-{
- return t->barriers_supported;
-}
-EXPORT_SYMBOL(dm_table_barrier_ok);
-
EXPORT_SYMBOL(dm_vcalloc);
EXPORT_SYMBOL(dm_get_device);
EXPORT_SYMBOL(dm_put_device);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 25d86e2..ab3b5d8 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -851,11 +851,7 @@
bio_io_error(bio);
return;
}
- if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
- dm_table_put(ci.map);
- bio_endio(bio, -EOPNOTSUPP);
- return;
- }
+
ci.md = md;
ci.bio = bio;
ci.io = alloc_io(md);
@@ -937,6 +933,15 @@
struct mapped_device *md = q->queuedata;
int cpu;
+ /*
+ * There is no use in forwarding any barrier request since we can't
+ * guarantee it is (or can be) handled by the targets correctly.
+ */
+ if (unlikely(bio_barrier(bio))) {
+ bio_endio(bio, -EOPNOTSUPP);
+ return 0;
+ }
+
down_read(&md->io_lock);
cpu = part_stat_lock();
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index b48397c0..a31506d 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -52,7 +52,6 @@
* To check the return value from dm_table_find_target().
*/
#define dm_target_is_valid(t) ((t)->table)
-int dm_table_barrier_ok(struct dm_table *t);
/*-----------------------------------------------------------------
* A registry of target types.