From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001
From: Zeng Chi <zengchi@kylinos.cn>
Date: Mon, 21 Sep 2026 18:24:42 +0800
Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL
 attributes

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>
---
 Documentation/driver-api/basics.rst | 151 ++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 Documentation/driver-api/basics.rst

(limited to 'Documentation/driver-api/basics.rst')

diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
new file mode 100644
index 000000000..3b182cfdf
--- /dev/null
+++ b/Documentation/driver-api/basics.rst
@@ -0,0 +1,151 @@
+Driver Basics
+=============
+
+Driver Entry and Exit points
+----------------------------
+
+.. kernel-doc:: include/linux/module.h
+   :internal:
+
+Driver device table
+-------------------
+
+.. kernel-doc:: include/linux/mod_devicetable.h
+   :internal:
+   :no-identifiers: pci_device_id
+
+
+Delaying and scheduling routines
+--------------------------------
+
+.. kernel-doc:: include/linux/sched.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/core.c
+   :export:
+
+.. kernel-doc:: kernel/sched/cpupri.c
+   :internal:
+
+.. kernel-doc:: kernel/sched/fair.c
+   :internal:
+
+.. kernel-doc:: include/linux/completion.h
+   :internal:
+
+Time and timer routines
+-----------------------
+
+.. kernel-doc:: include/linux/jiffies.h
+   :internal:
+
+.. kernel-doc:: kernel/time/time.c
+   :export:
+
+.. kernel-doc:: kernel/time/timer.c
+   :export:
+
+High-resolution timers
+----------------------
+
+.. kernel-doc:: include/linux/ktime.h
+   :internal:
+
+.. kernel-doc:: include/linux/hrtimer.h
+   :internal:
+
+.. kernel-doc:: kernel/time/hrtimer.c
+   :export:
+
+Wait queues and Wake events
+---------------------------
+
+.. kernel-doc:: include/linux/wait.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/wait.c
+   :export:
+
+Internal Functions
+------------------
+
+.. kernel-doc:: kernel/exit.c
+   :internal:
+
+.. kernel-doc:: kernel/signal.c
+   :internal:
+
+.. kernel-doc:: include/linux/kthread.h
+   :internal:
+
+.. kernel-doc:: kernel/kthread.c
+   :export:
+
+Reference counting
+------------------
+
+.. kernel-doc:: include/linux/refcount.h
+   :internal:
+
+.. kernel-doc:: lib/refcount.c
+   :export:
+
+.. kernel-doc:: include/linux/percpu-refcount.h
+.. kernel-doc:: lib/percpu-refcount.c
+
+Atomics
+-------
+
+.. kernel-doc:: include/linux/atomic/atomic-instrumented.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-arch-fallback.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-long.h
+   :internal:
+
+Kernel objects manipulation
+---------------------------
+
+.. kernel-doc:: lib/kobject.c
+   :export:
+
+.. kernel-doc:: lib/kobject_uevent.c
+   :export:
+
+Kernel utility functions
+------------------------
+
+.. kernel-doc:: include/linux/array_size.h
+   :internal:
+
+.. kernel-doc:: include/linux/container_of.h
+   :internal:
+
+.. kernel-doc:: include/linux/kstrtox.h
+   :internal:
+   :no-identifiers: kstrtol kstrtoul
+
+.. kernel-doc:: include/linux/stddef.h
+   :internal:
+
+.. kernel-doc:: include/linux/util_macros.h
+   :internal:
+
+.. kernel-doc:: include/linux/wordpart.h
+   :internal:
+
+.. kernel-doc:: kernel/printk/printk.c
+   :export:
+   :no-identifiers: printk
+
+.. kernel-doc:: kernel/panic.c
+   :export:
+
+Device Resource Management
+--------------------------
+
+.. kernel-doc:: drivers/base/devres.c
+   :export:
+
-- 
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