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-rw-r--r--drivers/md/dm-crypt.c2
-rw-r--r--drivers/md/dm-table.c19
-rw-r--r--include/linux/device-mapper.h5
3 files changed, 26 insertions, 0 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 49da55c..8c2a000 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1698,6 +1698,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->num_flush_requests = 1;
+ ti->discard_zeroes_data_unsupported = 1;
+
return 0;
bad:
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 3226698..bc04518 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1283,6 +1283,22 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
return 0;
}
+static bool dm_table_discard_zeroes_data(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i = 0;
+
+ /* Ensure that all targets supports discard_zeroes_data. */
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+
+ if (ti->discard_zeroes_data_unsupported)
+ return 0;
+ }
+
+ return 1;
+}
+
void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
struct queue_limits *limits)
{
@@ -1305,6 +1321,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
}
blk_queue_flush(q, flush);
+ if (!dm_table_discard_zeroes_data(t))
+ q->limits.discard_zeroes_data = 0;
+
dm_table_set_integrity(t);
/*
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 3fa1f3d..99e3e50 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -197,6 +197,11 @@ struct dm_target {
* whether or not its underlying devices have support.
*/
unsigned discards_supported:1;
+
+ /*
+ * Set if this target does not return zeroes on discarded blocks.
+ */
+ unsigned discard_zeroes_data_unsupported:1;
};
/* Each target can link one of these into the table */
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