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, 28 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/time-utils.h b/drivers/md/dm-vdo/time-utils.h
new file mode 100644
index 000000000..5f1e850fd
--- /dev/null
+++ b/drivers/md/dm-vdo/time-utils.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef UDS_TIME_UTILS_H
+#define UDS_TIME_UTILS_H
+
+#include <linux/ktime.h>
+#include <linux/time.h>
+#include <linux/types.h>
+
+static inline s64 ktime_to_seconds(ktime_t reltime)
+{
+	return reltime / NSEC_PER_SEC;
+}
+
+static inline ktime_t current_time_ns(clockid_t clock)
+{
+	return clock == CLOCK_MONOTONIC ? ktime_get_ns() : ktime_get_real_ns();
+}
+
+static inline ktime_t current_time_us(void)
+{
+	return current_time_ns(CLOCK_REALTIME) / NSEC_PER_USEC;
+}
+
+#endif /* UDS_TIME_UTILS_H */