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From: Petr Mladek <pmladek@suse.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: rafael@kernel.org, linux-kernel@vger.kernel.org,
	Rob Herring <robh@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	devicetree@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: Re: [PATCH v4 10/11] lib/vsprintf: Add %pfw conversion specifier for printing fwnode names
Date: Tue, 3 Sep 2019 15:06:07 +0200
Message-ID: <20190903130607.cf2qv3s3evobbd5g@pathway.suse.cz> (raw)
In-Reply-To: <20190902083240.20367-11-sakari.ailus@linux.intel.com>

On Mon 2019-09-02 11:32:39, Sakari Ailus wrote:
> Add support for %pfw conversion specifier (with "f" and "P" modifiers) to
> support printing full path of the node, including its name ("f") and only
> the node's name ("P") in the printk family of functions. The two flags
> have equivalent functionality to existing %pOF with the same two modifiers
> ("f" and "P") on OF based systems. The ability to do the same on ACPI
> based systems is added by this patch.
> diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
> index 922a29eb70e6c..abba210f67567 100644
> --- a/Documentation/core-api/printk-formats.rst
> +++ b/Documentation/core-api/printk-formats.rst
> @@ -418,6 +418,30 @@ Examples::
>  
>  Passed by reference.
>  
> +Fwnode handles
> +--------------
> +
> +::
> +
> +	%pfw[fP]
> +
> +For printing information on fwnode handles. The default is to print the full
> +node name, including the path. The modifiers are functionally equivalent to
> +%pOF above.
> +
> +	- f - full name of the node, including the path
> +	- P - the name of the node including an address (if there is one)
> +
> +Examples (ACPI):

s/:/::/ for the .rst formar.

> +
> +	%pfwf	\_SB.PCI0.CIO2.port@1.endpoint@0	- Full node name
> +	%pfwP	endpoint@0				- Node name
> +
> +Examples (OF):

Same here.

> +
> +	%pfwf	/ocp@68000000/i2c@48072000/camera@10/port/endpoint - Full name
> +	%pfwP	endpoint				- Node name
> +
>  Time and date (struct rtc_time)
>  -------------------------------
>  
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 4ad9332d54ba6..b9b4c835db063 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1981,6 +1981,36 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
>  	return widen_string(buf, buf - buf_start, end, spec);
>  }
>  
> +static noinline_for_stack
> +char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
> +		    struct printf_spec spec, const char *fmt)
> +{
> +	struct printf_spec str_spec = spec;
> +	char *buf_start = buf;
> +
> +	str_spec.field_width = -1;
> +
> +	if (*fmt != 'w')
> +		return error_string(buf, end, "(%pfw?)", spec);

This means that only "%pfw" will dereference the pointer by
fwnode_full_name_string() or fwnode_get_name(). All the other
eventual misuses of the obsolete %pf format will result in this
error message.

OK, it is hard to imagine using "%pf" to get symbol name and always add
'w' suffix. Therefore it looks that reusing the obsolete %pf format
modifier is pretty safe after all.


> +	if (check_pointer(&buf, end, fwnode, spec))
> +		return buf;
> +
> +	fmt++;
> +
> +	switch (*fmt) {
> +	case 'f':	/* full_name */
> +	default:

Using default: in the middle of switch might cause a lot of confusion.
Please, make it the last label.


> +		buf = fwnode_full_name_string(fwnode, buf, end);
> +		break;
> +	case 'P':	/* name */
> +		buf = string(buf, end, fwnode_get_name(fwnode), str_spec);
> +		break;
> +	}
> +
> +	return widen_string(buf, buf - buf_start, end, spec);
> +}
> +
>  /*
>   * Show a '%p' thing.  A kernel extension is that the '%p' is followed
>   * by an extra set of alphanumeric characters that are extended format
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index a60c241112cd4..8df50911ff4e9 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -5995,7 +5995,8 @@ sub process {
>  				while ($fmt =~ /(\%[\*\d\.]*p(\w))/g) {
>  					$specifier = $1;
>  					$extension = $2;
> -					if ($extension !~ /[SsBKRraEhMmIiUDdgVCbGNOxt]/) {
> +					if ($extension !~ /[SsBKRraEhMmIiUDdgVCbGNOxtf]/ ||
> +					    $extension =~ /^f[^w]/) {

This does not work. $extension seems to have only one character.

Best Regards,
Petr


  reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02  8:32 [PATCH v4 00/11] Device property improvements, add %pfw format specifier Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 01/11] software node: Get reference to parent swnode in get_parent op Sakari Ailus
2019-09-02 10:10   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 02/11] software node: Make argument to to_software_node const Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 03/11] device property: Move fwnode_get_parent() up Sakari Ailus
2019-09-02 10:11   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 04/11] device property: Add functions for accessing node's parents Sakari Ailus
2019-09-02 10:14   ` Andy Shevchenko
2019-09-02 12:34     ` Sakari Ailus
2019-09-02 12:46       ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 05/11] device property: Add fwnode_get_name for returning the name of a node Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 06/11] device property: Add a function to obtain a node's prefix Sakari Ailus
2019-09-02 10:16   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 07/11] lib/vsprintf: Remove support for %pF and %pf in favour of %pS and %ps Sakari Ailus
2019-09-02 14:39   ` Petr Mladek
2019-09-02 16:01     ` Andy Shevchenko
2019-09-03 14:04       ` Petr Mladek
2019-09-06  6:59         ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 08/11] lib/vsprintf: Make use of fwnode API to obtain node names and separators Sakari Ailus
2019-09-02 15:18   ` Petr Mladek
2019-09-02 15:41     ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 09/11] lib/vsprintf: OF nodes are first and foremost, struct device_nodes Sakari Ailus
2019-09-02 10:21   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 10/11] lib/vsprintf: Add %pfw conversion specifier for printing fwnode names Sakari Ailus
2019-09-03 13:06   ` Petr Mladek [this message]
2019-09-04 15:04     ` Sakari Ailus
2019-09-04 15:17       ` Andy Shevchenko
2019-09-04 15:39         ` Joe Perches
2019-09-04 15:54           ` Andy Shevchenko
2019-09-04 15:37       ` Joe Perches
2019-09-04 16:09         ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 11/11] lib/test_printf: Add tests for %pfw printk modifier Sakari Ailus
2019-09-02 12:26   ` Andy Shevchenko
2019-09-02 13:09     ` Sakari Ailus
2019-09-03 13:38   ` Petr Mladek
2019-09-04 14:03     ` Sakari Ailus

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