[RFC PATCH -next v3 04/10] nvmet: set WZDS and DRB if device supports BLK_FEAT_WRITE_ZEROES_UNMAP

Zhang Yi
2025-03-18T07:44:15Z

From: Zhang Yi <yi.zhang@huawei.com>

Set WZDS and DRB bit to the namespace dlfeat if the underlying block
device supports BLK_FEAT_WRITE_ZEROES_UNMAP, make the nvme target
device supports unmaped write zeroes command.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
drivers/nvme/target/io-cmd-bdev.c | 4 ++++
include/linux/blkdev.h | 5 +++++
2 files changed, 9 insertions(+)

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 83be0657e6df..0e8b35732492 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -46,6 +46,10 @@ void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
id->npda = id->npdg;
/* NOWS = Namespace Optimal Write Size */
id->nows = to0based(bdev_io_opt(bdev) / bdev_logical_block_size(bdev));
+
+ /* Set WZDS and DRB if device supports unmapped write zeroes */
+ if (bdev_unmap_write_zeroes(bdev))
+ id->dlfeat = (1 << 3) | 0x1;
}

void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5d280c7fba65..836738ab1fa6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1344,6 +1344,11 @@ static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
return bdev_limits(bdev)->max_write_zeroes_sectors;
}

+static inline bool bdev_unmap_write_zeroes(struct block_device *bdev)
+{
+ return bdev_limits(bdev)->features & BLK_FEAT_WRITE_ZEROES_UNMAP;
+}
+
static inline bool bdev_nonrot(struct block_device *bdev)
{
return blk_queue_nonrot(bdev_get_queue(bdev));
--
2.46.1