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, 14 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-net-dsa b/Documentation/ABI/testing/sysfs-class-net-dsa
new file mode 100644
index 000000000..e2da26b44
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-net-dsa
@@ -0,0 +1,14 @@
+What:		/sys/class/net/<iface>/dsa/tagging
+Date:		August 2018
+KernelVersion:	4.20
+Contact:	netdev@vger.kernel.org
+Description:
+		On read, this file returns a string indicating the type of
+		tagging protocol used by the DSA network devices that are
+		attached to this master interface.
+		On write, this file changes the tagging protocol of the
+		attached DSA switches, if this operation is supported by the
+		driver. Changing the tagging protocol must be done with the DSA
+		interfaces and the master interface all administratively down.
+		See the "name" field of each registered struct dsa_device_ops
+		for a list of valid values.