scsi: drbd: Remove WRITE_SAME support

REQ_OP_WRITE_SAME was only ever submitted by the legacy Linux zeroing code,
which has switched to use REQ_OP_WRITE_ZEROES long ago.

Link: https://lore.kernel.org/r/20220209082828.2629273-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 2 insertions, 70 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 44ccf8b4f4b2..02030c9c4d3b 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1265,71 +1265,6 @@ static void fixup_write_zeroes(struct drbd_device *device, struct request_queue
 		q->limits.max_write_zeroes_sectors = 0;
 }
 
-static void decide_on_write_same_support(struct drbd_device *device,
-			struct request_queue *q,
-			struct request_queue *b, struct o_qlim *o,
-			bool disable_write_same)
-{
-	struct drbd_peer_device *peer_device = first_peer_device(device);
-	struct drbd_connection *connection = peer_device->connection;
-	bool can_do = b ? b->limits.max_write_same_sectors : true;
-
-	if (can_do && disable_write_same) {
-		can_do = false;
-		drbd_info(peer_device, "WRITE_SAME disabled by config\n");
-	}
-
-	if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_WSAME)) {
-		can_do = false;
-		drbd_info(peer_device, "peer does not support WRITE_SAME\n");
-	}
-
-	if (o) {
-		/* logical block size; queue_logical_block_size(NULL) is 512 */
-		unsigned int peer_lbs = be32_to_cpu(o->logical_block_size);
-		unsigned int me_lbs_b = queue_logical_block_size(b);
-		unsigned int me_lbs = queue_logical_block_size(q);
-
-		if (me_lbs_b != me_lbs) {
-			drbd_warn(device,
-				"logical block size of local backend does not match (drbd:%u, backend:%u); was this a late attach?\n",
-				me_lbs, me_lbs_b);
-			/* rather disable write same than trigger some BUG_ON later in the scsi layer. */
-			can_do = false;
-		}
-		if (me_lbs_b != peer_lbs) {
-			drbd_warn(peer_device, "logical block sizes do not match (me:%u, peer:%u); this may cause problems.\n",
-				me_lbs, peer_lbs);
-			if (can_do) {
-				drbd_dbg(peer_device, "logical block size mismatch: WRITE_SAME disabled.\n");
-				can_do = false;
-			}
-			me_lbs = max(me_lbs, me_lbs_b);
-			/* We cannot change the logical block size of an in-use queue.
-			 * We can only hope that access happens to be properly aligned.
-			 * If not, the peer will likely produce an IO error, and detach. */
-			if (peer_lbs > me_lbs) {
-				if (device->state.role != R_PRIMARY) {
-					blk_queue_logical_block_size(q, peer_lbs);
-					drbd_warn(peer_device, "logical block size set to %u\n", peer_lbs);
-				} else {
-					drbd_warn(peer_device,
-						"current Primary must NOT adjust logical block size (%u -> %u); hope for the best.\n",
-						me_lbs, peer_lbs);
-				}
-			}
-		}
-		if (can_do && !o->write_same_capable) {
-			/* If we introduce an open-coded write-same loop on the receiving side,
-			 * the peer would present itself as "capable". */
-			drbd_dbg(peer_device, "WRITE_SAME disabled (peer device not capable)\n");
-			can_do = false;
-		}
-	}
-
-	blk_queue_max_write_same_sectors(q, can_do ? DRBD_MAX_BBIO_SECTORS : 0);
-}
-
 static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,
 				   unsigned int max_bio_size, struct o_qlim *o)
 {
@@ -1339,7 +1274,6 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 	struct request_queue *b = NULL;
 	struct disk_conf *dc;
 	bool discard_zeroes_if_aligned = true;
-	bool disable_write_same = false;
 
 	if (bdev) {
 		b = bdev->backing_bdev->bd_disk->queue;
@@ -1349,7 +1283,6 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 		dc = rcu_dereference(device->ldev->disk_conf);
 		max_segments = dc->max_bio_bvecs;
 		discard_zeroes_if_aligned = dc->discard_zeroes_if_aligned;
-		disable_write_same = dc->disable_write_same;
 		rcu_read_unlock();
 
 		blk_set_stacking_limits(&q->limits);
@@ -1360,7 +1293,6 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 	blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
 	blk_queue_segment_boundary(q, PAGE_SIZE-1);
 	decide_on_discard_support(device, q, b, discard_zeroes_if_aligned);
-	decide_on_write_same_support(device, q, b, o, disable_write_same);
 
 	if (b) {
 		blk_stack_limits(&q->limits, &b->limits, 0);
@@ -1666,8 +1598,8 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 	if (write_ordering_changed(old_disk_conf, new_disk_conf))
 		drbd_bump_write_ordering(device->resource, NULL, WO_BDEV_FLUSH);
 
-	if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned
-	||  old_disk_conf->disable_write_same != new_disk_conf->disable_write_same)
+	if (old_disk_conf->discard_zeroes_if_aligned !=
+	    new_disk_conf->discard_zeroes_if_aligned)
 		drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
 	drbd_md_sync(device);