From: NeilBrown <neilb@xxxxxxx>
DM currently implements congestion checking by checking on congestion
in each component device. For raid456 we need to also check if the
stripe cache is congested.
Add per-target congestion checker callback support and establish the
raid_is_congested() callback for dm-raid.
Extending the target_callbacks structure with additional callback
functions allows for establishing multiple callbacks per-target (a
callback is also needed for unplug).
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-raid.c | 18 ++++++++++++++++--
drivers/md/dm-table.c | 15 +++++++++++++++
include/linux/device-mapper.h | 12 ++++++++++++
3 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index edcccd8..962f88f 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -58,6 +58,7 @@ struct raid_set {
struct mddev_s md;
struct raid_type *raid_type;
+ struct target_callbacks callbacks;
struct raid_dev dev[0];
};
@@ -363,6 +364,13 @@ static void do_table_event(struct work_struct *ws)
dm_table_event(rs->ti->table);
}
+static int raid_is_congested(void *v, int bits)
+{
+ struct target_callbacks *cb = v;
+ struct raid_set *rs = container_of(cb, struct raid_set,
+ callbacks);
+ return md_raid5_congested(&rs->md, bits);
+}
/*
* Construct a RAID4/5/6 mapping:
* Args:
@@ -443,8 +451,13 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
rs->md.in_sync = 0; /* Assume already marked dirty */
mutex_unlock(&rs->md.reconfig_mutex);
- if (!errnum)
- return 0;
+ if (errnum)
+ goto err;
+
+ rs->callbacks.congested_fn = raid_is_congested;
+ dm_table_add_callbacks(ti->table, &rs->callbacks);
+
+ return 0;
err:
if (rs)
@@ -457,6 +470,7 @@ static void raid_dtr(struct dm_target *ti)
{
struct raid_set *rs = ti->private;
+ list_del_init(&rs->callbacks.list);
md_stop(&rs->md);
context_free(rs);
}
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 90267f8..88df831 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -71,6 +71,8 @@ struct dm_table {
void *event_context;
struct dm_md_mempools *mempools;
+
+ struct list_head target_callbacks;
};
/*
@@ -204,6 +206,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
return -ENOMEM;
INIT_LIST_HEAD(&t->devices);
+ INIT_LIST_HEAD(&t->target_callbacks);
atomic_set(&t->holders, 0);
t->discards_supported = 1;
@@ -1229,10 +1232,18 @@ int dm_table_resume_targets(struct dm_table *t)
return 0;
}
+void dm_table_add_callbacks(struct dm_table *t,
+ struct target_callbacks *cb)
+{
+ list_add(&cb->list, &t->target_callbacks);
+}
+EXPORT_SYMBOL_GPL(dm_table_add_callbacks);
+
int dm_table_any_congested(struct dm_table *t, int bdi_bits)
{
struct dm_dev_internal *dd;
struct list_head *devices = dm_table_get_devices(t);
+ struct target_callbacks *cb;
int r = 0;
list_for_each_entry(dd, devices, list) {
@@ -1247,6 +1258,10 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
bdevname(dd->dm_dev.bdev, b));
}
+ list_for_each_entry(cb, &t->target_callbacks, list)
+ if (cb->congested_fn)
+ r |= cb->congested_fn(cb, bdi_bits);
+
return r;
}
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 2970022..77e2e78 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -193,6 +193,12 @@ struct dm_target {
char *error;
};
+/* Each target can link one of these into the table */
+struct target_callbacks {
+ struct list_head list;
+ congested_fn *congested_fn;
+};
+
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);
@@ -269,6 +275,12 @@ int dm_table_add_target(struct dm_table *t, const char *type,
sector_t start, sector_t len, char *params);
/*
+ * Target_ctr should call this if they need to add any
+ * callback
+ */
+void dm_table_add_callbacks(struct dm_table *t,
+ struct target_callbacks *cb);
+/*
* Finally call this to make the table ready for use.
*/
int dm_table_complete(struct dm_table *t);
--
1.7.2.3
--
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