[PATCH v8 4/5] dm: Add block provisioning support

[Sarthak Kukreti <sarthakkukreti@chromium.org>]

Add block provisioning support for device-mapper targets.
dm-crypt and dm-linear will, by default, passthrough REQ_OP_PROVISION
requests to the underlying device, if supported.

Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm-crypt.c         |  4 +++-
 drivers/md/dm-linear.c        |  1 +
 drivers/md/dm-table.c         | 23 +++++++++++++++++++++++
 drivers/md/dm.c               |  7 +++++++
 include/linux/device-mapper.h | 17 +++++++++++++++++
 5 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f2662c21a6df..8f94d98e241b 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3362,6 +3362,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		cc->tag_pool_max_sectors <<= cc->sector_shift;
 	}
 
+	ti->num_provision_bios = 1;
+
 	ret = -ENOMEM;
 	cc->io_queue = alloc_workqueue("kcryptd_io/%s", WQ_MEM_RECLAIM, 1, devname);
 	if (!cc->io_queue) {
@@ -3416,7 +3418,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
 	 * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
 	 */
 	if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
-	    bio_op(bio) == REQ_OP_DISCARD)) {
+	    bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_PROVISION)) {
 		bio_set_dev(bio, cc->dev->bdev);
 		if (bio_sectors(bio))
 			bio->bi_iter.bi_sector = cc->start +
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index f4448d520ee9..74ee27ca551a 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -62,6 +62,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	ti->num_discard_bios = 1;
 	ti->num_secure_erase_bios = 1;
 	ti->num_write_zeroes_bios = 1;
+	ti->num_provision_bios = 1;
 	ti->private = lc;
 	return 0;
 
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 37b48f63ae6a..1839317d047e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1856,6 +1856,26 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t)
 	return true;
 }
 
+static int device_provision_capable(struct dm_target *ti, struct dm_dev *dev,
+				    sector_t start, sector_t len, void *data)
+{
+	return bdev_max_provision_sectors(dev->bdev);
+}
+
+static bool dm_table_supports_provision(struct dm_table *t)
+{
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
+		if (ti->provision_supported ||
+		    (ti->type->iterate_devices &&
+		    ti->type->iterate_devices(ti, device_provision_capable, NULL)))
+			return true;
+	}
+
+	return false;
+}
+
 static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev,
 				     sector_t start, sector_t len, void *data)
 {
@@ -1989,6 +2009,9 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	if (!dm_table_supports_write_zeroes(t))
 		q->limits.max_write_zeroes_sectors = 0;
 
+	if (!dm_table_supports_provision(t))
+		q->limits.max_provision_sectors = 0;
+
 	dm_table_verify_integrity(t);
 
 	/*
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 64a1f306c96c..0e6cf1a5a414 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1598,6 +1598,7 @@ static bool is_abnormal_io(struct bio *bio)
 		case REQ_OP_DISCARD:
 		case REQ_OP_SECURE_ERASE:
 		case REQ_OP_WRITE_ZEROES:
+		case REQ_OP_PROVISION:
 			return true;
 		default:
 			break;
@@ -1634,6 +1635,12 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci,
 		if (ti->max_write_zeroes_granularity)
 			max_granularity = max_sectors;
 		break;
+	case REQ_OP_PROVISION:
+		num_bios = ti->num_provision_bios;
+		max_sectors = limits->max_provision_sectors;
+		if (ti->max_provision_granularity)
+			max_granularity = max_sectors;
+		break;
 	default:
 		break;
 	}
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 69d0435c7ebb..41fd4e456d1f 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -332,6 +332,12 @@ struct dm_target {
 	 */
 	unsigned int num_write_zeroes_bios;
 
+	/*
+	 * The number of PROVISION bios that will be submitted to the target.
+	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
+	 */
+	unsigned int num_provision_bios;
+
 	/*
 	 * The minimum number of extra bytes allocated in each io for the
 	 * target to use.
@@ -356,6 +362,11 @@ struct dm_target {
 	 */
 	bool discards_supported:1;
 
+	/* Set if this target needs to receive provision requests regardless of
+	 * whether or not its underlying devices have support.
+	 */
+	bool provision_supported:1;
+
 	/*
 	 * Set if this target requires that discards be split on
 	 * 'max_discard_sectors' boundaries.
@@ -374,6 +385,12 @@ struct dm_target {
 	 */
 	bool max_write_zeroes_granularity:1;
 
+	/*
+	 * Set if this target requires that provisions be split on
+	 * 'max_provision_sectors' boundaries.
+	 */
+	bool max_provision_granularity:1;
+
 	/*
 	 * Set if we need to limit the number of in-flight bios when swapping.
 	 */
-- 
2.42.0.609.gbb76f46606-goog