Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/4/20 10:44 PM, Masami Hiramatsu wrote:
> Update boot configuration documentation.
> 
>  - Not using "config" abbreviation but configuration or description.
>  - Rewrite descriptions of node and its maxinum number.
>  - Add a section of use cases of boot configuration.
>  - Move how to use bootconfig to earlier section.
>  - Fix some typos, indents and format mistakes.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Hi Masami,

I swear that I am not trying to cause another version...

> ---
> Changes in v5:
>  - Elaborate the document.
>  - Fix some typos.
> Changes in v4:
>  - Remove O= option from examples.
> Changes in v3:
>  - Specify that comments also count in size.
>  - Fix a confusing sentence.
>  - Add O=<builddir> to make command.
> Changes in v2:
>  - Fixes additional typos (Thanks Markus and Randy!)
>  - Change a section title to "Tree Structured Key".
> ---
>  Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
>  Documentation/trace/boottime-trace.rst   |    2 
>  2 files changed, 131 insertions(+), 72 deletions(-)
> 
> diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> index cf2edcd09183..3bfc9ddf68e1 100644
> --- a/Documentation/admin-guide/bootconfig.rst
> +++ b/Documentation/admin-guide/bootconfig.rst
> @@ -11,25 +11,106 @@ Boot Configuration

> +When to Use the Boot Configuration?
> +-----------------------------------
> +
> +The boot configuration supports kernel command line options and init daemon
> +boot options. All sub-keys under "kernel" root key are passed as a part of
> +the kernel command line [1]_, and ones under "init" root key are passed as
> +a part of the init daemon's command line. For example, ::
> +
> +   root=UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82 ro quiet splash console=ttyS0,115200n8 console=tty0
> +
> +This can be written as following boot configuration file.::
> +
> +   kernel {
> +      root = "UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82" # nvme0n1p3
> +      ro       # mount rootfs as read only
> +      quiet    # No console log
> +      splash   # show splash image on boot screen
> +      console = "ttyS0,115200n8" # 1st console to serial device
> +      console += tty0            # add 2nd console
> +   }
> +
> +If you think that kernel/init options becomes too long to write in boot-loader

                                         become

> +configuration file or you want to comment on each option, the boot
> +configuration may be suitable. If unsure, you can still continue to use the
> +legacy kernel command line.


> +Boot Configuration Syntax
> +=========================
> +
> +The boot configuration syntax is a simple structured key-value. Each key
> +consists of dot-connected-words, and key and value are connected by ``=``.
> +The value has to be terminated by semicolon (``;``) or newline (``\n``).
> +For an array, its entries are separated by comma (``,``). ::
> +
> +  KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
>  
>  Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
>  
>  Each key word must contain only alphabets, numbers, dash (``-``) or underscore
>  (``_``). And each value only contains printable characters or spaces except
> -for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
> +for delimiters such as semicolon (``;``), new-line (``\n``), comma (``,``),

            usually called:                  newline

>  hash (``#``) and closing brace (``}``).
>  
>  If you want to use those delimiters in a value, you can use either double-


>  Comments
>  --------
>  
> -The config syntax accepts shell-script style comments. The comments starting
> -with hash ("#") until newline ("\n") will be ignored.
> -
> -::
> +The boot configuration accepts shell-script style comments. The comments,
> +beginning with hash (``#``) continues until newline (``\n``), will be

                               and continuing until newline

> +skipped.::
>  
>   # comment line
>   foo = value # value is set to foo.


Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

thanks.
-- 
~Randy