Re: [PATCH] kobject: return -ENOSPC when add_uevent_var() fails

[Greg Kroah-Hartman]

On Tue, Jun 11, 2019 at 06:09:55AM +0900, Masahiro Yamada wrote:
> On Tue, Jun 11, 2019 at 2:47 AM Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Wed, Jun 05, 2019 at 02:44:12AM +0900, Masahiro Yamada wrote:
> > > This function never attempts to allocate memory, so returning -ENOMEM
> > > looks weird to me. The reason of the failure is there is no more space
> > > in the given kobj_uevent_env structure.
> > >
> > > No caller of this function relies on this functing returning a specific
> > > error code, so just change it to return -ENOSPC. The intended change,
> > > if any, is the error number displayed in log messages.
> > >
> > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> > > ---
> > >
> > >  lib/kobject_uevent.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
> > > index 7998affa45d4..5ffd44bf4aad 100644
> > > --- a/lib/kobject_uevent.c
> > > +++ b/lib/kobject_uevent.c
> > > @@ -647,7 +647,7 @@ EXPORT_SYMBOL_GPL(kobject_uevent);
> > >   * @env: environment buffer structure
> > >   * @format: printf format for the key=value pair
> > >   *
> > > - * Returns 0 if environment variable was added successfully or -ENOMEM
> > > + * Returns 0 if environment variable was added successfully or -ENOSPC
> > >   * if no space was available.
> > >   */
> > >  int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
> > > @@ -657,7 +657,7 @@ int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
> > >
> > >       if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
> > >               WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
> > > -             return -ENOMEM;
> > > +             return -ENOSPC;
> >
> > As Rafael says, changing this for no good reason is not a good idea,
> > sorry.  Let's live with it as-is unless you can show some place where
> > this specific error value is causing problems.
> 
> 
> 
> Didn't you see WARN() above the return code?

Yes.

> I rephrased the commit log for clarification in v2.

It still doesn't matter :)

thanks,

greg k-h