Bjorn Helgaas
c7c90e121e
Extend IS_MODULE() and IS_ENABLED comments to explain why one might use "#if IS_ENABLED(CONFIG_FOO)" instead of "#ifdef CONFIG_FOO". To wit, "#ifdef CONFIG_FOO" is true only for CONFIG_FOO=y, while "#if IS_ENABLED(CONFIG_FOO)" is true for both CONFIG_FOO=y and CONFIG_FOO=m. This is because "CONFIG_FOO=m" in .config does not result in "CONFIG_FOO" being defined. The actual definitions are in autoconf.h, where: CONFIG_FOO=y results in #define CONFIG_FOO 1 CONFIG_FOO=m results in #define CONFIG_FOO_MODULE 1 Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.