>From mbroz@xxxxxxxxxx Thu Jan 8 11:14:02 2009
Date: Thu, 08 Jan 2009 17:13:12 +0100
From: Milan Broz <mbroz@xxxxxxxxxx>
Reply-To: device-mapper development <dm-devel@xxxxxxxxxx>
To: device-mapper development <dm-devel@xxxxxxxxxx>
Subject: [PATCH 1/4] dm-core: remove current partial barrier implementation
Prepare for full barrier implementation - remove the simple one
Signed-off-by: Milan Broz <mbroz@xxxxxxxxxx>
---
drivers/md/dm-linear.c | 1 -
drivers/md/dm-table.c | 19 -------------------
drivers/md/dm.c | 15 ++++++++++-----
drivers/md/dm.h | 1 -
include/linux/device-mapper.h | 1 -
5 files changed, 10 insertions(+), 27 deletions(-)
Index: linux-2.6.29-rc3-devel/drivers/md/dm-linear.c
===================================================================
--- linux-2.6.29-rc3-devel.orig/drivers/md/dm-linear.c 2009-02-05 05:33:47.000000000 +0100
+++ linux-2.6.29-rc3-devel/drivers/md/dm-linear.c 2009-02-05 05:33:52.000000000 +0100
@@ -142,7 +142,6 @@ static struct target_type linear_target
.status = linear_status,
.ioctl = linear_ioctl,
.merge = linear_merge,
- .features = DM_TARGET_SUPPORTS_BARRIERS,
};
int __init dm_linear_init(void)
Index: linux-2.6.29-rc3-devel/drivers/md/dm-table.c
===================================================================
--- linux-2.6.29-rc3-devel.orig/drivers/md/dm-table.c 2009-02-05 05:33:48.000000000 +0100
+++ linux-2.6.29-rc3-devel/drivers/md/dm-table.c 2009-02-05 05:33:52.000000000 +0100
@@ -52,8 +52,6 @@ struct dm_table {
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
@@ -240,7 +238,6 @@ int dm_table_create(struct dm_table **re
INIT_LIST_HEAD(&t->devices);
atomic_set(&t->holders, 0);
- t->barriers_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -741,10 +738,6 @@ int dm_table_add_target(struct dm_table
/* 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:
@@ -789,12 +782,6 @@ int dm_table_complete(struct dm_table *t
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);
@@ -1008,12 +995,6 @@ struct mapped_device *dm_table_get_md(st
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);
Index: linux-2.6.29-rc3-devel/drivers/md/dm.c
===================================================================
--- linux-2.6.29-rc3-devel.orig/drivers/md/dm.c 2009-02-05 05:33:51.000000000 +0100
+++ linux-2.6.29-rc3-devel/drivers/md/dm.c 2009-02-05 05:33:52.000000000 +0100
@@ -831,11 +831,7 @@ static void __process_bio(struct mapped_
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);
@@ -917,6 +913,15 @@ static int dm_request(struct request_que
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();
Index: linux-2.6.29-rc3-devel/drivers/md/dm.h
===================================================================
--- linux-2.6.29-rc3-devel.orig/drivers/md/dm.h 2009-02-05 05:33:48.000000000 +0100
+++ linux-2.6.29-rc3-devel/drivers/md/dm.h 2009-02-05 05:33:52.000000000 +0100
@@ -52,7 +52,6 @@ int dm_table_any_congested(struct dm_tab
* 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.
Index: linux-2.6.29-rc3-devel/include/linux/device-mapper.h
===================================================================
--- linux-2.6.29-rc3-devel.orig/include/linux/device-mapper.h 2009-02-05 05:33:48.000000000 +0100
+++ linux-2.6.29-rc3-devel/include/linux/device-mapper.h 2009-02-05 05:33:52.000000000 +0100
@@ -116,7 +116,6 @@ void dm_put_device(struct dm_target *ti,
/*
* Target features
*/
-#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001
struct target_type {
uint64_t features;
--
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