null_blk: don't allow discard for zoned mode

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>

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 8efd877..ce9e336 100644 (file)
--- 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);