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

Pull documentation format standardization from Jonathan Corbet:
 "This series converts a number of top-level documents to the RST format
  without incorporating them into the Sphinx tree. The hope is to bring
  some uniformity to kernel documentation and, perhaps more importantly,
  have our existing docs serve as an example of the desired formatting
  for those that will be added later.

  Mauro has gone through and fixed up a lot of top-level documentation
  files to make them conform to the RST format, but without moving or
  renaming them in any way. This will help when we incorporate the ones
  we want to keep into the Sphinx doctree, but the real purpose is to
  bring a bit of uniformity to our documentation and let the top-level
  docs serve as examples for those writing new ones"

* tag 'standardize-docs' of git://git.lwn.net/linux: (84 commits)
  docs: kprobes.txt: Fix whitespacing
  tee.txt: standardize document format
  cgroup-v2.txt: standardize document format
  dell_rbu.txt: standardize document format
  zorro.txt: standardize document format
  xz.txt: standardize document format
  xillybus.txt: standardize document format
  vfio.txt: standardize document format
  vfio-mediated-device.txt: standardize document format
  unaligned-memory-access.txt: standardize document format
  this_cpu_ops.txt: standardize document format
  svga.txt: standardize document format
  static-keys.txt: standardize document format
  smsc_ece1099.txt: standardize document format
  SM501.txt: standardize document format
  siphash.txt: standardize document format
  sgi-ioc4.txt: standardize document format
  SAK.txt: standardize document format
  rpmsg.txt: standardize document format
  robust-futexes.txt: standardize document format
  ...

1 files changed, 108 insertions, 99 deletions

diff --git a/Documentation/static-keys.txt b/Documentation/static-keys.txt
index ef419fd0897f..b83dfa1c0602 100644
--- a/Documentation/static-keys.txt
+++ b/Documentation/static-keys.txt
@@ -1,30 +1,34 @@
-			Static Keys
-			-----------
+===========
+Static Keys
+===========
 
-DEPRECATED API:
+.. warning::
 
-The use of 'struct static_key' directly, is now DEPRECATED. In addition
-static_key_{true,false}() is also DEPRECATED. IE DO NOT use the following:
+   DEPRECATED API:
 
-struct static_key false = STATIC_KEY_INIT_FALSE;
-struct static_key true = STATIC_KEY_INIT_TRUE;
-static_key_true()
-static_key_false()
+   The use of 'struct static_key' directly, is now DEPRECATED. In addition
+   static_key_{true,false}() is also DEPRECATED. IE DO NOT use the following::
 
-The updated API replacements are:
+	struct static_key false = STATIC_KEY_INIT_FALSE;
+	struct static_key true = STATIC_KEY_INIT_TRUE;
+	static_key_true()
+	static_key_false()
 
-DEFINE_STATIC_KEY_TRUE(key);
-DEFINE_STATIC_KEY_FALSE(key);
-DEFINE_STATIC_KEY_ARRAY_TRUE(keys, count);
-DEFINE_STATIC_KEY_ARRAY_FALSE(keys, count);
-static_branch_likely()
-static_branch_unlikely()
+   The updated API replacements are::
 
-0) Abstract
+	DEFINE_STATIC_KEY_TRUE(key);
+	DEFINE_STATIC_KEY_FALSE(key);
+	DEFINE_STATIC_KEY_ARRAY_TRUE(keys, count);
+	DEFINE_STATIC_KEY_ARRAY_FALSE(keys, count);
+	static_branch_likely()
+	static_branch_unlikely()
+
+Abstract
+========
 
 Static keys allows the inclusion of seldom used features in
 performance-sensitive fast-path kernel code, via a GCC feature and a code
-patching technique. A quick example:
+patching technique. A quick example::
 
 	DEFINE_STATIC_KEY_FALSE(key);
 
@@ -45,7 +49,8 @@ The static_branch_unlikely() branch will be generated into the code with as litt
 impact to the likely code path as possible.
 
 
-1) Motivation
+Motivation
+==========
 
 
 Currently, tracepoints are implemented using a conditional branch. The
@@ -60,7 +65,8 @@ possible. Although tracepoints are the original motivation for this work, other
 kernel code paths should be able to make use of the static keys facility.
 
 
-2) Solution
+Solution
+========
 
 
 gcc (v4.5) adds a new 'asm goto' statement that allows branching to a label:
@@ -71,7 +77,7 @@ Using the 'asm goto', we can create branches that are either taken or not taken
 by default, without the need to check memory. Then, at run-time, we can patch
 the branch site to change the branch direction.
 
-For example, if we have a simple branch that is disabled by default:
+For example, if we have a simple branch that is disabled by default::
 
 	if (static_branch_unlikely(&key))
 		printk("I am the true branch\n");
@@ -87,14 +93,15 @@ optimization.
 This lowlevel patching mechanism is called 'jump label patching', and it gives
 the basis for the static keys facility.
 
-3) Static key label API, usage and examples:
+Static key label API, usage and examples
+========================================
 
 
-In order to make use of this optimization you must first define a key:
+In order to make use of this optimization you must first define a key::
 
 	DEFINE_STATIC_KEY_TRUE(key);
 
-or:
+or::
 
 	DEFINE_STATIC_KEY_FALSE(key);
 
@@ -102,14 +109,14 @@ or:
 The key must be global, that is, it can't be allocated on the stack or dynamically
 allocated at run-time.
 
-The key is then used in code as:
+The key is then used in code as::
 
         if (static_branch_unlikely(&key))
                 do unlikely code
         else
                 do likely code
 
-Or:
+Or::
 
         if (static_branch_likely(&key))
                 do likely code
@@ -120,15 +127,15 @@ Keys defined via DEFINE_STATIC_KEY_TRUE(), or DEFINE_STATIC_KEY_FALSE, may
 be used in either static_branch_likely() or static_branch_unlikely()
 statements.
 
-Branch(es) can be set true via:
+Branch(es) can be set true via::
 
-static_branch_enable(&key);
+	static_branch_enable(&key);
 
-or false via:
+or false via::
 
-static_branch_disable(&key);
+	static_branch_disable(&key);
 
-The branch(es) can then be switched via reference counts:
+The branch(es) can then be switched via reference counts::
 
 	static_branch_inc(&key);
 	...
@@ -142,11 +149,11 @@ static_branch_inc(), will change the branch back to true. Likewise, if the
 key is initialized false, a 'static_branch_inc()', will change the branch to
 true. And then a 'static_branch_dec()', will again make the branch false.
 
-Where an array of keys is required, it can be defined as:
+Where an array of keys is required, it can be defined as::
 
 	DEFINE_STATIC_KEY_ARRAY_TRUE(keys, count);
 
-or:
+or::
 
 	DEFINE_STATIC_KEY_ARRAY_FALSE(keys, count);
 
@@ -159,96 +166,98 @@ simply fall back to a traditional, load, test, and jump sequence. Also, the
 struct jump_entry table must be at least 4-byte aligned because the
 static_key->entry field makes use of the two least significant bits.
 
-* select HAVE_ARCH_JUMP_LABEL, see: arch/x86/Kconfig
-
-* #define JUMP_LABEL_NOP_SIZE, see: arch/x86/include/asm/jump_label.h
+* ``select HAVE_ARCH_JUMP_LABEL``,
+    see: arch/x86/Kconfig
 
-* __always_inline bool arch_static_branch(struct static_key *key, bool branch), see:
-					arch/x86/include/asm/jump_label.h
+* ``#define JUMP_LABEL_NOP_SIZE``,
+    see: arch/x86/include/asm/jump_label.h
 
-* __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch),
-					see: arch/x86/include/asm/jump_label.h
+* ``__always_inline bool arch_static_branch(struct static_key *key, bool branch)``,
+    see: arch/x86/include/asm/jump_label.h
 
-* void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type),
-					see: arch/x86/kernel/jump_label.c
+* ``__always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)``,
+    see: arch/x86/include/asm/jump_label.h
 
-* __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type),
-					see: arch/x86/kernel/jump_label.c
+* ``void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type)``,
+    see: arch/x86/kernel/jump_label.c
 
+* ``__init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type)``,
+    see: arch/x86/kernel/jump_label.c
 
-* struct jump_entry, see: arch/x86/include/asm/jump_label.h
+* ``struct jump_entry``,
+    see: arch/x86/include/asm/jump_label.h
 
 
 5) Static keys / jump label analysis, results (x86_64):
 
 
 As an example, let's add the following branch to 'getppid()', such that the
-system call now looks like:
+system call now looks like::
 
-SYSCALL_DEFINE0(getppid)
-{
+  SYSCALL_DEFINE0(getppid)
+  {
         int pid;
 
-+       if (static_branch_unlikely(&key))
-+               printk("I am the true branch\n");
+  +     if (static_branch_unlikely(&key))
+  +             printk("I am the true branch\n");
 
         rcu_read_lock();
         pid = task_tgid_vnr(rcu_dereference(current->real_parent));
         rcu_read_unlock();
 
         return pid;
-}
-
-The resulting instructions with jump labels generated by GCC is:
-
-ffffffff81044290 <sys_getppid>:
-ffffffff81044290:       55                      push   %rbp
-ffffffff81044291:       48 89 e5                mov    %rsp,%rbp
-ffffffff81044294:       e9 00 00 00 00          jmpq   ffffffff81044299 <sys_getppid+0x9>
-ffffffff81044299:       65 48 8b 04 25 c0 b6    mov    %gs:0xb6c0,%rax
-ffffffff810442a0:       00 00
-ffffffff810442a2:       48 8b 80 80 02 00 00    mov    0x280(%rax),%rax
-ffffffff810442a9:       48 8b 80 b0 02 00 00    mov    0x2b0(%rax),%rax
-ffffffff810442b0:       48 8b b8 e8 02 00 00    mov    0x2e8(%rax),%rdi
-ffffffff810442b7:       e8 f4 d9 00 00          callq  ffffffff81051cb0 <pid_vnr>
-ffffffff810442bc:       5d                      pop    %rbp
-ffffffff810442bd:       48 98                   cltq
-ffffffff810442bf:       c3                      retq
-ffffffff810442c0:       48 c7 c7 e3 54 98 81    mov    $0xffffffff819854e3,%rdi
-ffffffff810442c7:       31 c0                   xor    %eax,%eax
-ffffffff810442c9:       e8 71 13 6d 00          callq  ffffffff8171563f <printk>
-ffffffff810442ce:       eb c9                   jmp    ffffffff81044299 <sys_getppid+0x9>
-
-Without the jump label optimization it looks like:
-
-ffffffff810441f0 <sys_getppid>:
-ffffffff810441f0:       8b 05 8a 52 d8 00       mov    0xd8528a(%rip),%eax        # ffffffff81dc9480 <key>
-ffffffff810441f6:       55                      push   %rbp
-ffffffff810441f7:       48 89 e5                mov    %rsp,%rbp
-ffffffff810441fa:       85 c0                   test   %eax,%eax
-ffffffff810441fc:       75 27                   jne    ffffffff81044225 <sys_getppid+0x35>
-ffffffff810441fe:       65 48 8b 04 25 c0 b6    mov    %gs:0xb6c0,%rax
-ffffffff81044205:       00 00
-ffffffff81044207:       48 8b 80 80 02 00 00    mov    0x280(%rax),%rax
-ffffffff8104420e:       48 8b 80 b0 02 00 00    mov    0x2b0(%rax),%rax
-ffffffff81044215:       48 8b b8 e8 02 00 00    mov    0x2e8(%rax),%rdi
-ffffffff8104421c:       e8 2f da 00 00          callq  ffffffff81051c50 <pid_vnr>
-ffffffff81044221:       5d                      pop    %rbp
-ffffffff81044222:       48 98                   cltq
-ffffffff81044224:       c3                      retq
-ffffffff81044225:       48 c7 c7 13 53 98 81    mov    $0xffffffff81985313,%rdi
-ffffffff8104422c:       31 c0                   xor    %eax,%eax
-ffffffff8104422e:       e8 60 0f 6d 00          callq  ffffffff81715193 <printk>
-ffffffff81044233:       eb c9                   jmp    ffffffff810441fe <sys_getppid+0xe>
-ffffffff81044235:       66 66 2e 0f 1f 84 00    data32 nopw %cs:0x0(%rax,%rax,1)
-ffffffff8104423c:       00 00 00 00
+  }
+
+The resulting instructions with jump labels generated by GCC is::
+
+  ffffffff81044290 <sys_getppid>:
+  ffffffff81044290:       55                      push   %rbp
+  ffffffff81044291:       48 89 e5                mov    %rsp,%rbp
+  ffffffff81044294:       e9 00 00 00 00          jmpq   ffffffff81044299 <sys_getppid+0x9>
+  ffffffff81044299:       65 48 8b 04 25 c0 b6    mov    %gs:0xb6c0,%rax
+  ffffffff810442a0:       00 00
+  ffffffff810442a2:       48 8b 80 80 02 00 00    mov    0x280(%rax),%rax
+  ffffffff810442a9:       48 8b 80 b0 02 00 00    mov    0x2b0(%rax),%rax
+  ffffffff810442b0:       48 8b b8 e8 02 00 00    mov    0x2e8(%rax),%rdi
+  ffffffff810442b7:       e8 f4 d9 00 00          callq  ffffffff81051cb0 <pid_vnr>
+  ffffffff810442bc:       5d                      pop    %rbp
+  ffffffff810442bd:       48 98                   cltq
+  ffffffff810442bf:       c3                      retq
+  ffffffff810442c0:       48 c7 c7 e3 54 98 81    mov    $0xffffffff819854e3,%rdi
+  ffffffff810442c7:       31 c0                   xor    %eax,%eax
+  ffffffff810442c9:       e8 71 13 6d 00          callq  ffffffff8171563f <printk>
+  ffffffff810442ce:       eb c9                   jmp    ffffffff81044299 <sys_getppid+0x9>
+
+Without the jump label optimization it looks like::
+
+  ffffffff810441f0 <sys_getppid>:
+  ffffffff810441f0:       8b 05 8a 52 d8 00       mov    0xd8528a(%rip),%eax        # ffffffff81dc9480 <key>
+  ffffffff810441f6:       55                      push   %rbp
+  ffffffff810441f7:       48 89 e5                mov    %rsp,%rbp
+  ffffffff810441fa:       85 c0                   test   %eax,%eax
+  ffffffff810441fc:       75 27                   jne    ffffffff81044225 <sys_getppid+0x35>
+  ffffffff810441fe:       65 48 8b 04 25 c0 b6    mov    %gs:0xb6c0,%rax
+  ffffffff81044205:       00 00
+  ffffffff81044207:       48 8b 80 80 02 00 00    mov    0x280(%rax),%rax
+  ffffffff8104420e:       48 8b 80 b0 02 00 00    mov    0x2b0(%rax),%rax
+  ffffffff81044215:       48 8b b8 e8 02 00 00    mov    0x2e8(%rax),%rdi
+  ffffffff8104421c:       e8 2f da 00 00          callq  ffffffff81051c50 <pid_vnr>
+  ffffffff81044221:       5d                      pop    %rbp
+  ffffffff81044222:       48 98                   cltq
+  ffffffff81044224:       c3                      retq
+  ffffffff81044225:       48 c7 c7 13 53 98 81    mov    $0xffffffff81985313,%rdi
+  ffffffff8104422c:       31 c0                   xor    %eax,%eax
+  ffffffff8104422e:       e8 60 0f 6d 00          callq  ffffffff81715193 <printk>
+  ffffffff81044233:       eb c9                   jmp    ffffffff810441fe <sys_getppid+0xe>
+  ffffffff81044235:       66 66 2e 0f 1f 84 00    data32 nopw %cs:0x0(%rax,%rax,1)
+  ffffffff8104423c:       00 00 00 00
 
 Thus, the disable jump label case adds a 'mov', 'test' and 'jne' instruction
 vs. the jump label case just has a 'no-op' or 'jmp 0'. (The jmp 0, is patched
 to a 5 byte atomic no-op instruction at boot-time.) Thus, the disabled jump
-label case adds:
+label case adds::
 
-6 (mov) + 2 (test) + 2 (jne) = 10 - 5 (5 byte jump 0) = 5 addition bytes.
+  6 (mov) + 2 (test) + 2 (jne) = 10 - 5 (5 byte jump 0) = 5 addition bytes.
 
 If we then include the padding bytes, the jump label code saves, 16 total bytes
 of instruction memory for this small function. In this case the non-jump label
@@ -262,7 +271,7 @@ Since there are a number of static key API uses in the scheduler paths,
 'pipe-test' (also known as 'perf bench sched pipe') can be used to show the
 performance improvement. Testing done on 3.3.0-rc2:
 
-jump label disabled:
+jump label disabled::
 
  Performance counter stats for 'bash -c /tmp/pipe-test' (50 runs):
 
@@ -279,7 +288,7 @@ jump label disabled:
 
        1.601607384 seconds time elapsed                                          ( +-  0.07% )
 
-jump label enabled:
+jump label enabled::
 
  Performance counter stats for 'bash -c /tmp/pipe-test' (50 runs):