dm: add support for secure erase forwarding

Set QUEUE_FLAG_SECERASE in DM device's queue_flags if a DM table's
data devices support secure erase.

Also, add support for secure erase to both the linear and striped
targets.
Signed-off-by: Denis Semakin <d.semakin@omprussia.ru>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-linear.c

@@ -59,6 +59,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_bios = 1;
 	ti->num_discard_bios = 1;
+	ti->num_secure_erase_bios = 1;
 	ti->num_write_same_bios = 1;
 	ti->num_write_zeroes_bios = 1;
 	ti->private = lc;

drivers/md/dm-stripe.c

@@ -169,6 +169,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_bios = stripes;
 	ti->num_discard_bios = stripes;
+	ti->num_secure_erase_bios = stripes;
 	ti->num_write_same_bios = stripes;
 	ti->num_write_zeroes_bios = stripes;
 
@@ -295,6 +296,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
 		return DM_MAPIO_REMAPPED;
 	}
 	if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
+	    unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
 	    unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES) ||
 	    unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) {
 		target_bio_nr = dm_bio_get_target_bio_nr(bio);

drivers/md/dm-table.c

@@ -1846,6 +1846,34 @@ static bool dm_table_supports_discards(struct dm_table *t)
 	return true;
 }
 
+static int device_not_secure_erase_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_secure_erase(q);
+}
+
+static bool dm_table_supports_secure_erase(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned int i;
+
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+
+		if (!ti->num_secure_erase_bios)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    ti->type->iterate_devices(ti, device_not_secure_erase_capable, NULL))
+			return false;
+	}
+
+	return true;
+}
+
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			       struct queue_limits *limits)
 {
@@ -1867,6 +1895,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	} else
 		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 
+	if (dm_table_supports_secure_erase(t))
+		queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
+
 	if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
 		wc = true;
 		if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))

drivers/md/dm.c

@@ -1414,6 +1414,11 @@ static unsigned get_num_discard_bios(struct dm_target *ti)
 	return ti->num_discard_bios;
 }
 
+static unsigned get_num_secure_erase_bios(struct dm_target *ti)
+{
+	return ti->num_secure_erase_bios;
+}
+
 static unsigned get_num_write_same_bios(struct dm_target *ti)
 {
 	return ti->num_write_same_bios;
@@ -1467,6 +1472,11 @@ static int __send_discard(struct clone_info *ci, struct dm_target *ti)
 					   is_split_required_for_discard);
 }
 
+static int __send_secure_erase(struct clone_info *ci, struct dm_target *ti)
+{
+	return __send_changing_extent_only(ci, ti, get_num_secure_erase_bios, NULL);
+}
+
 static int __send_write_same(struct clone_info *ci, struct dm_target *ti)
 {
 	return __send_changing_extent_only(ci, ti, get_num_write_same_bios, NULL);
@@ -1484,6 +1494,8 @@ static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
 
 	if (bio_op(bio) == REQ_OP_DISCARD)
 		*result = __send_discard(ci, ti);
+	else if (bio_op(bio) == REQ_OP_SECURE_ERASE)
+		*result = __send_secure_erase(ci, ti);
 	else if (bio_op(bio) == REQ_OP_WRITE_SAME)
 		*result = __send_write_same(ci, ti);
 	else if (bio_op(bio) == REQ_OP_WRITE_ZEROES)

include/linux/device-mapper.h

@@ -267,6 +267,12 @@ struct dm_target {
 	 */
 	unsigned num_discard_bios;
 
+	/*
+	 * The number of secure erase bios that will be submitted to the target.
+	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
+	 */
+	unsigned num_secure_erase_bios;
+
 	/*
 	 * The number of WRITE SAME bios that will be submitted to the target.
 	 * The bio number can be accessed with dm_bio_get_target_bio_nr.