[patch net-next] devlink: add format requirement for devlink param names

[patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

From: Jiri Pirko <jiri@mellanox.com>

Currently, the name format is not required by the code, however it is
required during patch review. All params added until now are in-lined
with the following format:
1) lowercase characters, digits and underscored are allowed
2) underscore is neither at the beginning nor at the end and
   there is no more than one in a row.

Add checker to the code to require this format from drivers and warn if
they don't follow.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
 net/core/devlink.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 97e9a2246929..5969cab5bc31 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/u64_stats_sync.h>
 #include <linux/timekeeping.h>
+#include <linux/ctype.h>
 #include <rdma/ib_verbs.h>
 #include <net/netlink.h>
 #include <net/genetlink.h>
@@ -7040,10 +7041,37 @@ void devlink_resource_occ_get_unregister(struct devlink *devlink,
 }
 EXPORT_SYMBOL_GPL(devlink_resource_occ_get_unregister);
 
+static bool devlink_param_valid_name(const char *name)
+{
+	int len = strlen(name);
+	int i;
+
+	/* Name can contain lowercase characters or digits.
+	 * Underscores are also allowed, but not at the beginning
+	 * or end of the name and not more than one in a row.
+	 */
+
+	for (i = 0; i < len; i++) {
+		if (islower(name[i]) || isdigit(name[i]))
+			continue;
+		if (name[i] != '_')
+			return false;
+		if (i == 0 || i + 1 == len)
+			return false;
+		if (name[i - 1] == '_')
+			return false;
+	}
+	return true;
+}
+
 static int devlink_param_verify(const struct devlink_param *param)
 {
 	if (!param || !param->name || !param->supported_cmodes)
 		return -EINVAL;
+
+	if (WARN_ON(!devlink_param_valid_name(param->name)))
+		return -EINVAL;
+
 	if (param->generic)
 		return devlink_param_generic_verify(param);
 	else
-- 
2.21.0

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jakub Kicinski]

On Fri, 18 Oct 2019 18:07:26 +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@mellanox.com>
> 
> Currently, the name format is not required by the code, however it is
> required during patch review. All params added until now are in-lined
> with the following format:
> 1) lowercase characters, digits and underscored are allowed
> 2) underscore is neither at the beginning nor at the end and
>    there is no more than one in a row.
> 
> Add checker to the code to require this format from drivers and warn if
> they don't follow.
> 
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>

Looks good, I could nit pick that length of 0 could also be disallowed
since we're checking validity, but why would I :)

Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

Fri, Oct 18, 2019 at 06:25:50PM CEST, jakub.kicinski@netronome.com wrote:
>On Fri, 18 Oct 2019 18:07:26 +0200, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@mellanox.com>
>> 
>> Currently, the name format is not required by the code, however it is
>> required during patch review. All params added until now are in-lined
>> with the following format:
>> 1) lowercase characters, digits and underscored are allowed
>> 2) underscore is neither at the beginning nor at the end and
>>    there is no more than one in a row.
>> 
>> Add checker to the code to require this format from drivers and warn if
>> they don't follow.
>> 
>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>
>Looks good, I could nit pick that length of 0 could also be disallowed
>since we're checking validity, but why would I :)

Okay.

>
>Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Re: [patch net-next] devlink: add format requirement for devlink param names

[Stephen Hemminger]

On Fri, 18 Oct 2019 18:07:26 +0200
Jiri Pirko <jiri@resnulli.us> wrote:

> +static bool devlink_param_valid_name(const char *name)
> +{
> +	int len = strlen(name);
> +	int i;
> +
> +	/* Name can contain lowercase characters or digits.
> +	 * Underscores are also allowed, but not at the beginning
> +	 * or end of the name and not more than one in a row.
> +	 */
> +
> +	for (i = 0; i < len; i++) {

Very minor stuff.
   1. since strlen technically returns size_t why not make both i and len type size_t
   2. no blank line after comment and before loop?

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

Fri, Oct 18, 2019 at 06:33:22PM CEST, stephen@networkplumber.org wrote:
>On Fri, 18 Oct 2019 18:07:26 +0200
>Jiri Pirko <jiri@resnulli.us> wrote:
>
>> +static bool devlink_param_valid_name(const char *name)
>> +{
>> +	int len = strlen(name);
>> +	int i;
>> +
>> +	/* Name can contain lowercase characters or digits.
>> +	 * Underscores are also allowed, but not at the beginning
>> +	 * or end of the name and not more than one in a row.
>> +	 */
>> +
>> +	for (i = 0; i < len; i++) {
>
>Very minor stuff.
>   1. since strlen technically returns size_t why not make both i and len type size_t
>   2. no blank line after comment and before loop?

Ok.

Re: [patch net-next] devlink: add format requirement for devlink param names

[Stephen Hemminger]

On Fri, 18 Oct 2019 18:07:26 +0200
Jiri Pirko <jiri@resnulli.us> wrote:

> +static bool devlink_param_valid_name(const char *name)
> +{
> +	int len = strlen(name);
> +	int i;
> +
> +	/* Name can contain lowercase characters or digits.
> +	 * Underscores are also allowed, but not at the beginning
> +	 * or end of the name and not more than one in a row.
> +	 */
> +
> +	for (i = 0; i < len; i++) {
> +		if (islower(name[i]) || isdigit(name[i]))
> +			continue;
> +		if (name[i] != '_')
> +			return false;
> +		if (i == 0 || i + 1 == len)
> +			return false;
> +		if (name[i - 1] == '_')
> +			return false;
> +	}
> +	return true;
> +}

You might want to also impose a maximum length on name,
and not allow slash in name (if you ever plan to use sysfs).

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

Fri, Oct 18, 2019 at 06:35:09PM CEST, stephen@networkplumber.org wrote:
>On Fri, 18 Oct 2019 18:07:26 +0200
>Jiri Pirko <jiri@resnulli.us> wrote:
>
>> +static bool devlink_param_valid_name(const char *name)
>> +{
>> +	int len = strlen(name);
>> +	int i;
>> +
>> +	/* Name can contain lowercase characters or digits.
>> +	 * Underscores are also allowed, but not at the beginning
>> +	 * or end of the name and not more than one in a row.
>> +	 */
>> +
>> +	for (i = 0; i < len; i++) {
>> +		if (islower(name[i]) || isdigit(name[i]))
>> +			continue;
>> +		if (name[i] != '_')
>> +			return false;
>> +		if (i == 0 || i + 1 == len)
>> +			return false;
>> +		if (name[i - 1] == '_')
>> +			return false;
>> +	}
>> +	return true;
>> +}
>
>You might want to also impose a maximum length on name,

Well I don't really see why.

>and not allow slash in name (if you ever plan to use sysfs).

They are not allowed. Only islower, isdigit, '_'. That's it.

Re: [patch net-next] devlink: add format requirement for devlink param names

[Andrew Lunn]

On Fri, Oct 18, 2019 at 06:07:26PM +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@mellanox.com>
> 
> Currently, the name format is not required by the code, however it is
> required during patch review. All params added until now are in-lined
> with the following format:
> 1) lowercase characters, digits and underscored are allowed
> 2) underscore is neither at the beginning nor at the end and
>    there is no more than one in a row.
> 
> Add checker to the code to require this format from drivers and warn if
> they don't follow.

Hi Jiri

Could you add a reference to where these requirements are derived
from. What can go wrong if they are ignored? I assume it is something
to do with sysfs?

      Andrew

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

Fri, Oct 18, 2019 at 07:43:04PM CEST, andrew@lunn.ch wrote:
>On Fri, Oct 18, 2019 at 06:07:26PM +0200, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@mellanox.com>
>> 
>> Currently, the name format is not required by the code, however it is
>> required during patch review. All params added until now are in-lined
>> with the following format:
>> 1) lowercase characters, digits and underscored are allowed
>> 2) underscore is neither at the beginning nor at the end and
>>    there is no more than one in a row.
>> 
>> Add checker to the code to require this format from drivers and warn if
>> they don't follow.
>
>Hi Jiri
>
>Could you add a reference to where these requirements are derived
>from. What can go wrong if they are ignored? I assume it is something

Well, no reference. All existing params, both generic and driver
specific are following this format. I just wanted to make that required
so all params are looking similar.


>to do with sysfs?

No, why would you think so?


>
>      Andrew

Re: [patch net-next] devlink: add format requirement for devlink param names

[Andrew Lunn]

On Fri, Oct 18, 2019 at 10:08:22PM +0200, Jiri Pirko wrote:
> Fri, Oct 18, 2019 at 07:43:04PM CEST, andrew@lunn.ch wrote:
> >On Fri, Oct 18, 2019 at 06:07:26PM +0200, Jiri Pirko wrote:
> >> From: Jiri Pirko <jiri@mellanox.com>
> >> 
> >> Currently, the name format is not required by the code, however it is
> >> required during patch review. All params added until now are in-lined
> >> with the following format:
> >> 1) lowercase characters, digits and underscored are allowed
> >> 2) underscore is neither at the beginning nor at the end and
> >>    there is no more than one in a row.
> >> 
> >> Add checker to the code to require this format from drivers and warn if
> >> they don't follow.
> >
> >Hi Jiri
> >
> >Could you add a reference to where these requirements are derived
> >from. What can go wrong if they are ignored? I assume it is something
> 
> Well, no reference. All existing params, both generic and driver
> specific are following this format. I just wanted to make that required
> so all params are looking similar.
> 
> 
> >to do with sysfs?
> 
> No, why would you think so?

I was not expecting it to be totally arbitrary. I thought you would
have a real technical reason. Spaces often cause problems, as well as
/ etc.

I've had problems with hwmon device names breaking assumptions in the
user space code, etc. I was expecting something like this.

I don't really like the all lower case restriction. It makes it hard
to be consistent. All Marvell Docs refer to the Address Translation
Unit as ATU. I don't think there is any reference to atu. I would
prefer to be consistent with the documentation and use ATU. But that
is against your arbitrary rules.

       Andrew

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jakub Kicinski]

On Fri, 18 Oct 2019 22:27:48 +0200, Andrew Lunn wrote:
> I don't really like the all lower case restriction. It makes it hard
> to be consistent. All Marvell Docs refer to the Address Translation
> Unit as ATU. I don't think there is any reference to atu. I would
> prefer to be consistent with the documentation and use ATU. But that
> is against your arbitrary rules.

So is MTU yet all command line params we take as input or output use
lower case.

I'm with Jiri.

Re: [patch net-next] devlink: add format requirement for devlink param names

[Jiri Pirko]

Fri, Oct 18, 2019 at 10:27:48PM CEST, andrew@lunn.ch wrote:
>On Fri, Oct 18, 2019 at 10:08:22PM +0200, Jiri Pirko wrote:
>> Fri, Oct 18, 2019 at 07:43:04PM CEST, andrew@lunn.ch wrote:
>> >On Fri, Oct 18, 2019 at 06:07:26PM +0200, Jiri Pirko wrote:
>> >> From: Jiri Pirko <jiri@mellanox.com>
>> >> 
>> >> Currently, the name format is not required by the code, however it is
>> >> required during patch review. All params added until now are in-lined
>> >> with the following format:
>> >> 1) lowercase characters, digits and underscored are allowed
>> >> 2) underscore is neither at the beginning nor at the end and
>> >>    there is no more than one in a row.
>> >> 
>> >> Add checker to the code to require this format from drivers and warn if
>> >> they don't follow.
>> >
>> >Hi Jiri
>> >
>> >Could you add a reference to where these requirements are derived
>> >from. What can go wrong if they are ignored? I assume it is something
>> 
>> Well, no reference. All existing params, both generic and driver
>> specific are following this format. I just wanted to make that required
>> so all params are looking similar.
>> 
>> 
>> >to do with sysfs?
>> 
>> No, why would you think so?
>
>I was not expecting it to be totally arbitrary. I thought you would
>have a real technical reason. Spaces often cause problems, as well as
>/ etc.
>
>I've had problems with hwmon device names breaking assumptions in the
>user space code, etc. I was expecting something like this.
>
>I don't really like the all lower case restriction. It makes it hard
>to be consistent. All Marvell Docs refer to the Address Translation
>Unit as ATU. I don't think there is any reference to atu. I would
>prefer to be consistent with the documentation and use ATU. But that
>is against your arbitrary rules.


There are already params with abbrs that could be upper case. So if we
do uppercase now, it would be inconsistent. I just
want the format to be as simple as possible. lowercase, digits and "_"
is very simple and can accomodate everything.


>
>       Andrew