KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/block/rnbd/Kconfig b/drivers/block/rnbd/Kconfig
new file mode 100644
index 000000000..2ff05a0d2
--- /dev/null
+++ b/drivers/block/rnbd/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+config BLK_DEV_RNBD
+	bool
+
+config BLK_DEV_RNBD_CLIENT
+	tristate "RDMA Network Block Device driver client"
+	depends on INFINIBAND_RTRS_CLIENT
+	select BLK_DEV_RNBD
+	select SG_POOL
+	help
+	  RNBD client is a network block device driver using rdma transport.
+
+	  RNBD client allows for mapping of a remote block devices over
+	  RTRS protocol from a target system where RNBD server is running.
+
+	  If unsure, say N.
+
+config BLK_DEV_RNBD_SERVER
+	tristate "RDMA Network Block Device driver server"
+	depends on INFINIBAND_RTRS_SERVER
+	select BLK_DEV_RNBD
+	help
+	  RNBD server is the server side of RNBD using rdma transport.
+
+	  RNBD server allows for exporting local block devices to a remote client
+	  over RTRS protocol.
+
+	  If unsure, say N.