The NBD protocol defines the flag NBD_FLAG_ROTATIONAL to flag that the
export in use should be treated as a rotational device.
Add support for that flag to the kernel driver.
Signed-off-by: Wouter Verhelst <w@xxxxxxx>
---
drivers/block/nbd.c | 3 +++
include/uapi/linux/nbd.h | 3 ++-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 41a90150b501..5b1811b1ba5f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -350,6 +350,9 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
lim.features |= BLK_FEAT_WRITE_CACHE;
lim.features &= ~BLK_FEAT_FUA;
}
+ if (nbd->config->flags & NBD_FLAG_ROTATIONAL)
+ lim.features |= BLK_FEAT_ROTATIONAL;
+
lim.logical_block_size = blksize;
lim.physical_block_size = blksize;
error = queue_limits_commit_update(nbd->disk->queue, &lim);
diff --git a/include/uapi/linux/nbd.h b/include/uapi/linux/nbd.h
index 80ce0ef43afd..d75215f2c675 100644
--- a/include/uapi/linux/nbd.h
+++ b/include/uapi/linux/nbd.h
@@ -51,8 +51,9 @@ enum {
#define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */
#define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */
#define NBD_FLAG_SEND_FUA (1 << 3) /* send FUA (forced unit access) */
-/* there is a gap here to match userspace */
+#define NBD_FLAG_ROTATIONAL (1 << 4) /* device is rotational */
#define NBD_FLAG_SEND_TRIM (1 << 5) /* send trim/discard */
+/* there is a gap here to match userspace */
#define NBD_FLAG_CAN_MULTI_CONN (1 << 8) /* Server supports multiple connections per export. */
/* values for cmd flags in the upper 16 bits of request type */
--
2.43.0
