From 3093a479727be194996dbc40f803711af5877be4 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 20 Jul 2020 08:12:49 +0200
Subject: [PATCH] block: inherit the zoned characteristics in blk_stack_limits
Git-commit: 3093a479727be194996dbc40f803711af5877be4
Patch-mainline: v5.9-rc1
References: bsc#1175995, jsc#SLE-15608

Lift the code from device mapper into blk_stack_limits to inherity
the stacking limitations.  This ensures we do the right thing for
all stacked zoned block devices.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 block/blk-settings.c   |  1 +
 drivers/md/dm-table.c  | 19 -------------------
 include/linux/blkdev.h |  9 ++++++---
 3 files changed, 7 insertions(+), 22 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 9a2c23cd9700..9cddbd736474 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -609,6 +609,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 		t->chunk_sectors = min_not_zero(t->chunk_sectors,
 						b->chunk_sectors);
 
+	t->zoned = max(t->zoned, b->zoned);
 	return ret;
 }
 EXPORT_SYMBOL(blk_stack_limits);
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 0ea5b7367179..ec5364133cef 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -467,9 +467,6 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 		       q->limits.logical_block_size,
 		       q->limits.alignment_offset,
 		       (unsigned long long) start << SECTOR_SHIFT);
-
-	limits->zoned = blk_queue_zoned_model(q);
-
 	return 0;
 }
 
@@ -1528,22 +1525,6 @@ int dm_calculate_queue_limits(struct dm_table *table,
 			       dm_device_name(table->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
-
-		/*
-		 * FIXME: this should likely be moved to blk_stack_limits(), would
-		 * also eliminate limits->zoned stacking hack in dm_set_device_limits()
-		 */
-		if (limits->zoned == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) {
-			/*
-			 * By default, the stacked limits zoned model is set to
-			 * BLK_ZONED_NONE in blk_set_stacking_limits(). Update
-			 * this model using the first target model reported
-			 * that is not BLK_ZONED_NONE. This will be either the
-			 * first target device zoned model or the model reported
-			 * by the target .io_hints.
-			 */
-			limits->zoned = ti_limits.zoned;
-		}
 	}
 
 	/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 63078944909c..9e331a1eb35f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -306,11 +306,14 @@ enum blk_queue_state {
 
 /*
  * Zoned block device models (zoned limit).
+ *
+ * Note: This needs to be ordered from the least to the most severe
+ * restrictions for the inheritance in blk_stack_limits() to work.
  */
 enum blk_zoned_model {
-	BLK_ZONED_NONE,	/* Regular block device */
-	BLK_ZONED_HA,	/* Host-aware zoned block device */
-	BLK_ZONED_HM,	/* Host-managed zoned block device */
+	BLK_ZONED_NONE = 0,	/* Regular block device */
+	BLK_ZONED_HA,		/* Host-aware zoned block device */
+	BLK_ZONED_HM,		/* Host-managed zoned block device */
 };
 
 struct queue_limits {
-- 
2.26.2