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path: root/drivers/md/dm-table.c
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Diffstat (limited to 'drivers/md/dm-table.c')
-rw-r--r--drivers/md/dm-table.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index bc60ef77a0d8..f9fc07d7a4b9 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -54,6 +54,8 @@ struct dm_table {
sector_t *highs;
struct dm_target *targets;
+ unsigned discards_supported:1;
+
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
@@ -203,6 +205,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
INIT_LIST_HEAD(&t->devices);
atomic_set(&t->holders, 0);
+ t->discards_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -770,6 +773,9 @@ int dm_table_add_target(struct dm_table *t, const char *type,
t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+ if (!tgt->num_discard_requests)
+ t->discards_supported = 0;
+
return 0;
bad:
@@ -1135,6 +1141,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
else
queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
+ if (!dm_table_supports_discards(t))
+ queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
+ else
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+
dm_table_set_integrity(t);
/*
@@ -1281,6 +1292,39 @@ struct mapped_device *dm_table_get_md(struct dm_table *t)
return t->md;
}
+static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
+ sector_t start, sector_t len, void *data)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+
+ return q && blk_queue_discard(q);
+}
+
+bool dm_table_supports_discards(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i = 0;
+
+ if (!t->discards_supported)
+ return 0;
+
+ /*
+ * Ensure that at least one underlying device supports discards.
+ * t->devices includes internal dm devices such as mirror logs
+ * so we need to use iterate_devices here, which targets
+ * supporting discard must provide.
+ */
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, device_discard_capable, NULL))
+ return 1;
+ }
+
+ return 0;
+}
+
EXPORT_SYMBOL(dm_vcalloc);
EXPORT_SYMBOL(dm_get_device);
EXPORT_SYMBOL(dm_put_device);