From: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Date: Wed, 20 May 2020 16:01:52 -0700
Subject: [PATCH] null_blk: don't allow discard for zoned mode
Git-commit: 1592cd15eec6e2952453f9a82da6e8a53e2b8db5
Patch-mainline: v5.7-rc7
References: bsc#1175995,jsc#SLE-15608

Zoned block device specification do not define the behavior of
discard/trim command as this command is generally replaced by the reset
write pointer (zone reset) command. Emulate this in null_blk by making
zoned and discard options mutually exclusive.

Suggested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/block/null_blk_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 8efd8778e209..ce9e33603a4d 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1535,6 +1535,13 @@ static void null_config_discard(struct nullb *nullb)
 {
 	if (nullb->dev->discard == false)
 		return;
+
+	if (nullb->dev->zoned) {
+		nullb->dev->discard = false;
+		pr_info("discard option is ignored in zoned mode\n");
+		return;
+	}
+
 	nullb->q->limits.discard_granularity = nullb->dev->blocksize;
 	nullb->q->limits.discard_alignment = nullb->dev->blocksize;
 	blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
-- 
2.16.4