Merge tag 'docs-5.10-2' of git://git.lwn.net/linux

Pull documentation fixes from Jonathan Corbet:
 "A handful of late-arriving documentation fixes"

* tag 'docs-5.10-2' of git://git.lwn.net/linux:
  docs: Add two missing entries in vm sysctl index
  docs/vm: trivial fixes to several spelling mistakes
  docs: submitting-patches: describe preserving review/test tags
  Documentation: Chinese translation of Documentation/arm64/hugetlbpage.rst
  Documentation: x86: fix a missing word in x86_64/mm.rst.
  docs: driver-api: remove a duplicated index entry
  docs: lkdtm: Modernize and improve details
  docs: deprecated.rst: Expand str*cpy() replacement notes
  docs/cpu-load: format the example code.

Author: torvalds

Documentation/admin-guide/cpu-load.rst

@@ -61,43 +61,46 @@ will lead to quite erratic information inside ``/proc/stat``::
 
 	static volatile sig_atomic_t stop;
 
-	static void sighandler (int signr)
+	static void sighandler(int signr)
 	{
-	(void) signr;
-	stop = 1;
+		(void) signr;
+		stop = 1;
 	}
+
 	static unsigned long hog (unsigned long niters)
 	{
-	stop = 0;
-	while (!stop && --niters);
-	return niters;
+		stop = 0;
+		while (!stop && --niters);
+		return niters;
 	}
+
 	int main (void)
 	{
-	int i;
-	struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 },
-				.it_value = { .tv_sec = 0, .tv_usec = 1 } };
-	sigset_t set;
-	unsigned long v[HIST];
-	double tmp = 0.0;
-	unsigned long n;
-	signal (SIGALRM, &sighandler);
-	setitimer (ITIMER_REAL, &it, NULL);
-
-	hog (ULONG_MAX);
-	for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog (ULONG_MAX);
-	for (i = 0; i < HIST; ++i) tmp += v[i];
-	tmp /= HIST;
-	n = tmp - (tmp / 3.0);
-
-	sigemptyset (&set);
-	sigaddset (&set, SIGALRM);
-
-	for (;;) {
-		hog (n);
-		sigwait (&set, &i);
-	}
-	return 0;
+		int i;
+		struct itimerval it = {
+			.it_interval = { .tv_sec = 0, .tv_usec = 1 },
+			.it_value    = { .tv_sec = 0, .tv_usec = 1 } };
+		sigset_t set;
+		unsigned long v[HIST];
+		double tmp = 0.0;
+		unsigned long n;
+		signal(SIGALRM, &sighandler);
+		setitimer(ITIMER_REAL, &it, NULL);
+
+		hog (ULONG_MAX);
+		for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog(ULONG_MAX);
+		for (i = 0; i < HIST; ++i) tmp += v[i];
+		tmp /= HIST;
+		n = tmp - (tmp / 3.0);
+
+		sigemptyset(&set);
+		sigaddset(&set, SIGALRM);
+
+		for (;;) {
+			hog(n);
+			sigwait(&set, &i);
+		}
+		return 0;
 	}
 
 

Documentation/admin-guide/sysctl/vm.rst

@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm:
 - admin_reserve_kbytes
 - block_dump
 - compact_memory
+- compaction_proactiveness
 - compact_unevictable_allowed
 - dirty_background_bytes
 - dirty_background_ratio
@@ -37,6 +38,7 @@ Currently, these files are in /proc/sys/vm:
 - dirty_writeback_centisecs
 - drop_caches
 - extfrag_threshold
+- highmem_is_dirtyable
 - hugetlb_shm_group
 - laptop_mode
 - legacy_va_layout

Documentation/arm64/hugetlbpage.rst

@@ -1,3 +1,5 @@
+.. _hugetlbpage_index:
+
 ====================
 HugeTLBpage on ARM64
 ====================

Documentation/driver-api/index.rst

@@ -77,7 +77,6 @@ available subsections can be seen below.
    console
    dcdbas
    eisa
-   ipmb
    isa
    isapnp
    io-mapping

Documentation/fault-injection/provoke-crashes.rst

@@ -1,48 +1,58 @@
-===============
-Provoke crashes
-===============
+.. SPDX-License-Identifier: GPL-2.0
 
-The lkdtm module provides an interface to crash or injure the kernel at
-predefined crashpoints to evaluate the reliability of crash dumps obtained
-using different dumping solutions. The module uses KPROBEs to instrument
-crashing points, but can also crash the kernel directly without KRPOBE
-support.
+============================================================
+Provoking crashes with Linux Kernel Dump Test Module (LKDTM)
+============================================================
 
+The lkdtm module provides an interface to disrupt (and usually crash)
+the kernel at predefined code locations to evaluate the reliability of
+the kernel's exception handling and to test crash dumps obtained using
+different dumping solutions. The module uses KPROBEs to instrument the
+trigger location, but can also trigger the kernel directly without KPROBE
+support via debugfs.
 
-You can provide the way either through module arguments when inserting
-the module, or through a debugfs interface.
+You can select the location of the trigger ("crash point name") and the
+type of action ("crash point type") either through module arguments when
+inserting the module, or through the debugfs interface.
 
 Usage::
 
 	insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<>
 			[cpoint_count={>0}]
 
 recur_count
-	Recursion level for the stack overflow test. Default is 10.
+	Recursion level for the stack overflow test. By default this is
+	dynamically calculated based on kernel configuration, with the
+	goal of being just large enough to exhaust the kernel stack. The
+	value can be seen at `/sys/module/lkdtm/parameters/recur_count`.
 
 cpoint_name
-	Crash point where the kernel is to be crashed. It can be
+	Where in the kernel to trigger the action. It can be
 	one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY,
 	FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD,
-	IDE_CORE_CP, DIRECT
+	IDE_CORE_CP, or DIRECT
 
 cpoint_type
 	Indicates the action to be taken on hitting the crash point.
-	It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW,
-	CORRUPT_STACK, UNALIGNED_LOAD_STORE_WRITE, OVERWRITE_ALLOCATION,
-	WRITE_AFTER_FREE,
+	These are numerous, and best queried directly from debugfs. Some
+	of the common ones are PANIC, BUG, EXCEPTION, LOOP, and OVERFLOW.
+	See the contents of `/sys/kernel/debug/provoke-crash/DIRECT` for
+	a complete list.
 
 cpoint_count
 	Indicates the number of times the crash point is to be hit
-	to trigger an action. The default is 10.
+	before triggering the action. The default is 10 (except for
+	DIRECT, which always fires immediately).
 
 You can also induce failures by mounting debugfs and writing the type to
-<mountpoint>/provoke-crash/<crashpoint>. E.g.::
+<debugfs>/provoke-crash/<crashpoint>. E.g.::
 
-  mount -t debugfs debugfs /mnt
-  echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY
+  mount -t debugfs debugfs /sys/kernel/debug
+  echo EXCEPTION > /sys/kernel/debug/provoke-crash/INT_HARDWARE_ENTRY
 
+The special file `DIRECT` will induce the action directly without KPROBE
+instrumentation. This mode is the only one available when the module is
+built for a kernel without KPROBEs support::
 
-A special file is `DIRECT` which will induce the crash directly without
-KPROBE instrumentation. This mode is the only one available when the module
-is built on a kernel without KPROBEs support.
+  # Instead of having a BUG kill your shell, have it kill "cat":
+  cat <(echo WRITE_RO) >/sys/kernel/debug/provoke-crash/DIRECT

Documentation/process/deprecated.rst

@@ -106,23 +106,29 @@ NUL or newline terminated.
 
 strcpy()
 --------
-strcpy() performs no bounds checking on the destination
-buffer. This could result in linear overflows beyond the
-end of the buffer, leading to all kinds of misbehaviors. While
-`CONFIG_FORTIFY_SOURCE=y` and various compiler flags help reduce the
-risk of using this function, there is no good reason to add new uses of
-this function. The safe replacement is strscpy().
+strcpy() performs no bounds checking on the destination buffer. This
+could result in linear overflows beyond the end of the buffer, leading to
+all kinds of misbehaviors. While `CONFIG_FORTIFY_SOURCE=y` and various
+compiler flags help reduce the risk of using this function, there is
+no good reason to add new uses of this function. The safe replacement
+is strscpy(), though care must be given to any cases where the return
+value of strcpy() was used, since strscpy() does not return a pointer to
+the destination, but rather a count of non-NUL bytes copied (or negative
+errno when it truncates).
 
 strncpy() on NUL-terminated strings
 -----------------------------------
-Use of strncpy() does not guarantee that the destination buffer
-will be NUL terminated. This can lead to various linear read overflows
-and other misbehavior due to the missing termination. It also NUL-pads the
-destination buffer if the source contents are shorter than the destination
-buffer size, which may be a needless performance penalty for callers using
-only NUL-terminated strings. The safe replacement is strscpy().
-(Users of strscpy() still needing NUL-padding should instead
-use strscpy_pad().)
+Use of strncpy() does not guarantee that the destination buffer will
+be NUL terminated. This can lead to various linear read overflows and
+other misbehavior due to the missing termination. It also NUL-pads
+the destination buffer if the source contents are shorter than the
+destination buffer size, which may be a needless performance penalty
+for callers using only NUL-terminated strings. The safe replacement is
+strscpy(), though care must be given to any cases where the return value
+of strncpy() was used, since strscpy() does not return a pointer to the
+destination, but rather a count of non-NUL bytes copied (or negative
+errno when it truncates). Any cases still needing NUL-padding should
+instead use strscpy_pad().
 
 If a caller is using non-NUL-terminated strings, strncpy() can
 still be used, but destinations should be marked with the `__nonstring
@@ -131,10 +137,12 @@ attribute to avoid future compiler warnings.
 
 strlcpy()
 ---------
-strlcpy() reads the entire source buffer first, possibly exceeding
-the given limit of bytes to copy. This is inefficient and can lead to
-linear read overflows if a source string is not NUL-terminated. The
-safe replacement is strscpy().
+strlcpy() reads the entire source buffer first (since the return value
+is meant to match that of strlen()). This read may exceed the destination
+size limit. This is both inefficient and can lead to linear read overflows
+if a source string is not NUL-terminated. The safe replacement is strscpy(),
+though care must be given to any cases where the return value of strlcpy()
+is used, since strscpy() will return negative errno values when it truncates.
 
 %p format specifier
 -------------------

Documentation/process/submitting-patches.rst

@@ -527,6 +527,13 @@ done on the patch.  Reviewed-by: tags, when supplied by reviewers known to
 understand the subject area and to perform thorough reviews, will normally
 increase the likelihood of your patch getting into the kernel.
 
+Both Tested-by and Reviewed-by tags, once received on mailing list from tester
+or reviewer, should be added by author to the applicable patches when sending
+next versions.  However if the patch has changed substantially in following
+version, these tags might not be applicable anymore and thus should be removed.
+Usually removal of someone's Tested-by or Reviewed-by tags should be mentioned
+in the patch changelog (after the '---' separator).
+
 A Suggested-by: tag indicates that the patch idea is suggested by the person
 named and ensures credit to the person for the idea. Please note that this
 tag should not be added without the reporter's permission, especially if the

Documentation/translations/zh_CN/arm64/hugetlbpage.rst

@@ -0,0 +1,45 @@
+.. include:: ../disclaimer-zh_CN.rst
+
+:Original: :ref:`Documentation/arm64/hugetlbpage.rst <hugetlbpage_index>`
+
+Translator: Bailu Lin <bailu.lin@vivo.com>
+
+=====================
+ARM64中的 HugeTLBpage
+=====================
+
+大页依靠有效利用 TLBs 来提高地址翻译的性能。这取决于以下
+两点 -
+
+  - 大页的大小
+  - TLBs 支持的条目大小
+
+ARM64 接口支持2种大页方式。
+
+1) pud/pmd 级别的块映射
+-----------------------
+
+这是常规大页，他们的 pmd 或 pud 页面表条目指向一个内存块。
+不管 TLB 中支持的条目大小如何，块映射可以减少翻译大页地址
+所需遍历的页表深度。
+
+2) 使用连续位
+-------------
+
+架构中转换页表条目(D4.5.3, ARM DDI 0487C.a)中提供一个连续
+位告诉 MMU 这个条目是一个连续条目集的一员，它可以被缓存在单
+个 TLB 条目中。
+
+在 Linux 中连续位用来增加 pmd 和 pte(最后一级)级别映射的大
+小。受支持的连续页表条目数量因页面大小和页表级别而异。
+
+
+支持以下大页尺寸配置 -
+
+  ====== ========   ====    ========    ===
+  -      CONT PTE    PMD    CONT PMD    PUD
+  ====== ========   ====    ========    ===
+  4K:         64K     2M         32M     1G
+  16K:         2M    32M          1G
+  64K:         2M   512M         16G
+  ====== ========   ====    ========    ===

Documentation/translations/zh_CN/arm64/index.rst

@@ -14,3 +14,4 @@ ARM64 架构
     :maxdepth: 2
 
     amu
+    hugetlbpage

Documentation/vm/mmu_notifier.rst

@@ -89,7 +89,7 @@ they are write protected for COW (other case of B apply too).
 
 So here because at time N+2 the clear page table entry was not pair with a
 notification to invalidate the secondary TLB, the device see the new value for
-addrB before seing the new value for addrA. This break total memory ordering
+addrB before seeing the new value for addrA. This break total memory ordering
 for the device.
 
 When changing a pte to write protect or to point to a new write protected page