[PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[Bo YU]

Fix warning form checkpatch, use pr_warn replace KERN_WARNING

Signed-off-by: Bo YU <tsu.yubo@gmail.com>
---
changes in v2:
According to Joe's suggestion,drop newline from msg, otherwise
it can be unterminated with newline.
---
 lib/kobject_uevent.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 63d0816ab23b..1837765ebf01 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -195,12 +195,12 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
 	enum kobject_action action;
 	const char *action_args;
 	struct kobj_uevent_env *env;
-	const char *msg = NULL, *devpath;
+	const char *msg = NULL;
 	int r;
 
 	r = kobject_action_type(buf, count, &action, &action_args);
 	if (r) {
-		msg = "unknown uevent action string\n";
+		msg = "unknown uevent action string";
 		goto out;
 	}
 
@@ -212,7 +212,7 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
 	r = kobject_action_args(action_args,
 				count - (action_args - buf), &env);
 	if (r == -EINVAL) {
-		msg = "incorrect uevent action arguments\n";
+		msg = "incorrect uevent action arguments";
 		goto out;
 	}
 
@@ -223,8 +223,9 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
 	kfree(env);
 out:
 	if (r) {
-		devpath = kobject_get_path(kobj, GFP_KERNEL);
-		printk(KERN_WARNING "synth uevent: %s: %s",
+		char *devpath = kobject_get_path(kobj, GFP_KERNEL);
+
+		pr_warn("synth uevent: %s: %s\n",
 		       devpath ?: "unknown device",
 		       msg ?: "failed to send uevent");
 		kfree(devpath);
-- 
2.11.0

Re: [PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[Rafael J. Wysocki]

On Tue, Nov 6, 2018 at 3:42 AM Bo YU <tsu.yubo@gmail.com> wrote:
>
> Fix warning form checkpatch, use pr_warn replace KERN_WARNING
>
> Signed-off-by: Bo YU <tsu.yubo@gmail.com>

First off, IMO, you should not change the existing code just in order
to make checkpatch happy about it.  That alone is not a good enough
reason for modifying it.

If the checkpatch warning indicates an issue like broken white space
(and I mean really broken and not lines longer than 80 chars etc),
then that may be a reason to modify the existing code, depending.

> ---
> changes in v2:
> According to Joe's suggestion,drop newline from msg, otherwise
> it can be unterminated with newline.
> ---
>  lib/kobject_uevent.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
> index 63d0816ab23b..1837765ebf01 100644
> --- a/lib/kobject_uevent.c
> +++ b/lib/kobject_uevent.c
> @@ -195,12 +195,12 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
>         enum kobject_action action;
>         const char *action_args;
>         struct kobj_uevent_env *env;
> -       const char *msg = NULL, *devpath;
> +       const char *msg = NULL;
>         int r;
>
>         r = kobject_action_type(buf, count, &action, &action_args);
>         if (r) {
> -               msg = "unknown uevent action string\n";
> +               msg = "unknown uevent action string";
>                 goto out;
>         }
>
> @@ -212,7 +212,7 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
>         r = kobject_action_args(action_args,
>                                 count - (action_args - buf), &env);
>         if (r == -EINVAL) {
> -               msg = "incorrect uevent action arguments\n";
> +               msg = "incorrect uevent action arguments";

Second, this change is not what the changelog of your patch is talking about.

>                 goto out;
>         }
>
> @@ -223,8 +223,9 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
>         kfree(env);
>  out:
>         if (r) {
> -               devpath = kobject_get_path(kobj, GFP_KERNEL);
> -               printk(KERN_WARNING "synth uevent: %s: %s",
> +               char *devpath = kobject_get_path(kobj, GFP_KERNEL);
> +
> +               pr_warn("synth uevent: %s: %s\n",
>                        devpath ?: "unknown device",
>                        msg ?: "failed to send uevent");
>                 kfree(devpath);
> --
> 2.11.0
>

Re: [PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[Joe Perches]

On Tue, 2018-11-06 at 08:49 +0100, Rafael J. Wysocki wrote:
> On Tue, Nov 6, 2018 at 3:42 AM Bo YU <tsu.yubo@gmail.com> wrote:
> > Fix warning form checkpatch, use pr_warn replace KERN_WARNING
> > 
> > Signed-off-by: Bo YU <tsu.yubo@gmail.com>
> 
> First off, IMO, you should not change the existing code just in order
> to make checkpatch happy about it.  That alone is not a good enough
> reason for modifying it.
> 
> If the checkpatch warning indicates an issue like broken white space
> (and I mean really broken and not lines longer than 80 chars etc),
> then that may be a reason to modify the existing code, depending.

Existing code is slightly broken.
There is currently a missing terminating newline in the
non-switch case match, when msg == NULL;

It might be simpler to initialize msg like

	const char *msg = "failed to send uevent";

and always use msg and not msg ?: in the printk.

> > changes in v2:
> > According to Joe's suggestion,drop newline from msg, otherwise
> > it can be unterminated with newline.ch
> > ---
> >  lib/kobject_uevent.c | 11 ++++++-----
> >  1 file changed, 6 insertions(+), 5 deletions(-)
> > 
> > diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
> > index 63d0816ab23b..1837765ebf01 100644
> > --- a/lib/kobject_uevent.c
> > +++ b/lib/kobject_uevent.c
> > @@ -195,12 +195,12 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
> >         enum kobject_action action;
> >         const char *action_args;
> >         struct kobj_uevent_env *env;
> > -       const char *msg = NULL, *devpath;
> > +       const char *msg = NULL;
> >         int r;
> > 
> >         r = kobject_action_type(buf, count, &action, &action_args);
> >         if (r) {
> > -               msg = "unknown uevent action string\n";
> > +               msg = "unknown uevent action string";
> >                 goto out;
> >         }
> > 
> > @@ -212,7 +212,7 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
> >         r = kobject_action_args(action_args,
> >                                 count - (action_args - buf), &env);
> >         if (r == -EINVAL) {
> > -               msg = "incorrect uevent action arguments\n";
> > +               msg = "incorrect uevent action arguments";
> 
> Second, this change is not what the changelog of your patch is talking about.
> 
> >                 goto out;
> >         }
> > 
> > @@ -223,8 +223,9 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
> >         kfree(env);
> >  out:
> >         if (r) {
> > -               devpath = kobject_get_path(kobj, GFP_KERNEL);
> > -               printk(KERN_WARNING "synth uevent: %s: %s",
> > +               char *devpath = kobject_get_path(kobj, GFP_KERNEL);
> > +
> > +               pr_warn("synth uevent: %s: %s\n",
> >                        devpath ?: "unknown device",
> >                        msg ?: "failed to send uevent");
> >                 kfree(devpath);
> > --
> > 2.11.0
> > 

Re: [PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[Rafael J. Wysocki]

On Tue, Nov 6, 2018 at 8:58 AM Joe Perches <joe@perches.com> wrote:
>
> On Tue, 2018-11-06 at 08:49 +0100, Rafael J. Wysocki wrote:
> > On Tue, Nov 6, 2018 at 3:42 AM Bo YU <tsu.yubo@gmail.com> wrote:
> > > Fix warning form checkpatch, use pr_warn replace KERN_WARNING
> > >
> > > Signed-off-by: Bo YU <tsu.yubo@gmail.com>
> >
> > First off, IMO, you should not change the existing code just in order
> > to make checkpatch happy about it.  That alone is not a good enough
> > reason for modifying it.
> >
> > If the checkpatch warning indicates an issue like broken white space
> > (and I mean really broken and not lines longer than 80 chars etc),
> > then that may be a reason to modify the existing code, depending.
>
> Existing code is slightly broken.
> There is currently a missing terminating newline in the
> non-switch case match, when msg == NULL;

OK, so this should be explained in the patch changelog.

Saying "I do this to make checkpatch happy" in the changelog is just
not enough IMO (if not outright misleading).

Re: [PATCH v2] kobject: to use pr_warn replace KERN_WARNING

[YU Bo]

On Tue, Nov 06, 2018 at 09:09:15AM +0100, Rafael J. Wysocki wrote:
>On Tue, Nov 6, 2018 at 8:58 AM Joe Perches <joe@perches.com> wrote:
>>
>> On Tue, 2018-11-06 at 08:49 +0100, Rafael J. Wysocki wrote:
>> > On Tue, Nov 6, 2018 at 3:42 AM Bo YU <tsu.yubo@gmail.com> wrote:
>> > > Fix warning form checkpatch, use pr_warn replace KERN_WARNING
>> > >
>> > > Signed-off-by: Bo YU <tsu.yubo@gmail.com>
>> >
>> > First off, IMO, you should not change the existing code just in order
>> > to make checkpatch happy about it.  That alone is not a good enough
>> > reason for modifying it.
>> >
>> > If the checkpatch warning indicates an issue like broken white space
>> > (and I mean really broken and not lines longer than 80 chars etc),
>> > then that may be a reason to modify the existing code, depending.
>>
>> Existing code is slightly broken.
>> There is currently a missing terminating newline in the
>> non-switch case match, when msg == NULL;
>
>OK, so this should be explained in the patch changelog.
>
>Saying "I do this to make checkpatch happy" in the changelog is just
>not enough IMO (if not outright misleading).
Using pr_* code become more and more in kernel when i read code and then i ask
for help from checkpatch. In commit log i just copy the what to to but not my
explations that why to do such.
I will send V3, thanks.