[PATCH v1 1/1] docs: Update documentation to avoid mentioning of kernel.h

Andy Shevchenko
2025-11-26T21:00:02Z

For several years, and still ongoing, the kernel.h is being split
to smaller and narrow headers to avoid "including everything" approach
which is bad in many ways. Since that, documentation missed a few
required updates to align with that work. Do it here.

Note, language translations are left untouched and if anybody willing
to help, please provide path(es) based on the updated English variant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Documentation/core-api/kobject.rst | 2 +-
Documentation/dev-tools/checkpatch.rst | 2 +-
Documentation/driver-api/basics.rst | 17 ++++++++++++++++-
.../driver-api/driver-model/design-patterns.rst | 2 +-
Documentation/process/coding-style.rst | 10 +++++++---
Documentation/staging/rpmsg.rst | 7 +++++--
6 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/Documentation/core-api/kobject.rst b/Documentation/core-api/kobject.rst
index 7310247310a0..5f6c61bc03bf 100644
--- a/Documentation/core-api/kobject.rst
+++ b/Documentation/core-api/kobject.rst
@@ -78,7 +78,7 @@ just a matter of using the kobj member. Code that works with kobjects will
often have the opposite problem, however: given a struct kobject pointer,
what is the pointer to the containing structure? You must avoid tricks
(such as assuming that the kobject is at the beginning of the structure)
-and, instead, use the container_of() macro, found in ``<linux/kernel.h>``::
+and, instead, use the container_of() macro, found in ``<linux/container_of.h>``::

container_of(ptr, type, member)

diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index fa2988dd4657..c1dff8e6bccb 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -753,7 +753,7 @@ Macros, Attributes and Symbols
sizeof(foo)/sizeof(foo[0]) for finding number of elements in an
array.

- The macro is defined in include/linux/kernel.h::
+ The macro is defined in include/linux/array_size.h::

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
index 5e9f7aee71a7..8b6a5888cb11 100644
--- a/Documentation/driver-api/basics.rst
+++ b/Documentation/driver-api/basics.rst
@@ -114,10 +114,25 @@ Kernel objects manipulation
Kernel utility functions
------------------------

-.. kernel-doc:: include/linux/kernel.h
+.. 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
diff --git a/Documentation/driver-api/driver-model/design-patterns.rst b/Documentation/driver-api/driver-model/design-patterns.rst
index 41eb8f41f7dd..965b2b93be6f 100644
--- a/Documentation/driver-api/driver-model/design-patterns.rst
+++ b/Documentation/driver-api/driver-model/design-patterns.rst
@@ -103,7 +103,7 @@ The design pattern is the same for an hrtimer or something similar that will
return a single argument which is a pointer to a struct member in the
callback.

-container_of() is a macro defined in <linux/kernel.h>
+container_of() is a macro defined in <linux/container_of.h>

What container_of() does is to obtain a pointer to the containing struct from
a pointer to a member by a simple subtraction using the offsetof() macro from
diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
index 2969ca378dbb..d63ea0bffdfe 100644
--- a/Documentation/process/coding-style.rst
+++ b/Documentation/process/coding-style.rst
@@ -1070,7 +1070,7 @@ readability.
18) Don't re-invent the kernel macros
-------------------------------------

-The header file include/linux/kernel.h contains a number of macros that
+There many header files in include/linux/ that contain a number of macros that
you should use, rather than explicitly coding some variant of them yourself.
For example, if you need to calculate the length of an array, take advantage
of the macro
@@ -1079,14 +1079,18 @@ of the macro

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

+which is defined in array_size.h.
+
Similarly, if you need to calculate the size of some structure member, use

.. code-block:: c

#define sizeof_field(t, f) (sizeof(((t*)0)->f))

-There are also min() and max() macros that do strict type checking if you
-need them. Feel free to peruse that header file to see what else is already
+which is defined in stddef.h.
+
+There are also min() and max() macros defined in minmax.h that do strict type checking if you
+need them. Feel free to peruse the header files to see what else is already
defined that you shouldn't reproduce in your code.

diff --git a/Documentation/staging/rpmsg.rst b/Documentation/staging/rpmsg.rst
index 40282cca86ca..42bac1149d9d 100644
--- a/Documentation/staging/rpmsg.rst
+++ b/Documentation/staging/rpmsg.rst
@@ -224,9 +224,12 @@ content to the console.

::

- #include <linux/kernel.h>
+ #include <linux/dev_printk.h>
+ #include <linux/mod_devicetable.h>
#include <linux/module.h>
+ #include <linux/printk.h>
#include <linux/rpmsg.h>
+ #include <linux/types.h>

static void rpmsg_sample_cb(struct rpmsg_channel *rpdev, void *data, int len,
void *priv, u32 src)
@@ -244,7 +247,7 @@ content to the console.
/* send a message on our channel */
err = rpmsg_send(rpdev->ept, "hello!", 6);
if (err) {
- pr_err("rpmsg_send failed: %d\n", err);
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", err);
return err;
}

--
2.50.1