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@xxxxxxxxx> wrote:
> > Fix warning form checkpatch, use pr_warn replace KERN_WARNING
> > 
> > Signed-off-by: Bo YU <tsu.yubo@xxxxxxxxx>
> 
> 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
> >