Re: [PATCH] arc:kernel:perf_event.c : replaced sprintf with sysfs_emit()

Re: [PATCH] arc:kernel:perf_event.c : replaced sprintf with sysfs_emit()

[Rujra Bhatt]

Hi,

On Sat, Jul 5, 2025 at 1:00 PM Rujra Bhatt <braker.noob.kernel@gmail.com> wrote:
>
> Replaced sprintf() with sysfs_emit() in sysfs*_show() function in
> perf_event.c file to follow the kernel's guidelines from
> documentation/filesystems/sysfs.rst
> This will improve consistency, safety, and makes it easier to maintain
> and update in future.
>
> Signed-off-by: Rujra Bhatt <braker.noob.kernel@gmail.com>
> ---
>  arch/arc/kernel/perf_event.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
> index ed6d4f0cd621..424ec072c441 100644
> --- a/arch/arc/kernel/perf_event.c
> +++ b/arch/arc/kernel/perf_event.c
> @@ -648,7 +648,7 @@ static ssize_t arc_pmu_events_sysfs_show(struct device *dev,
>         struct perf_pmu_events_attr *pmu_attr;
>
>         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
> -       return sprintf(page, "event=0x%04llx\n", pmu_attr->id);
> +       return sysfs_emit(page, "event=0x%04llx\n", pmu_attr->id);
>  }
>
>  /*
> --
> 2.43.0
>

Gentle reminder for the replacement of sprintf() with the sysfs_emit(), kindly
review it.

Thanking you,
regards,
Rujra Bhatt

Re: [PATCH] arc:kernel:perf_event.c : replaced sprintf with sysfs_emit()

[Greg KH]

On Fri, Jul 18, 2025 at 03:57:20PM +0530, Rujra Bhatt wrote:
> Hi,
> 
> On Sat, Jul 5, 2025 at 1:00 PM Rujra Bhatt <braker.noob.kernel@gmail.com> wrote:
> >
> > Replaced sprintf() with sysfs_emit() in sysfs*_show() function in
> > perf_event.c file to follow the kernel's guidelines from
> > documentation/filesystems/sysfs.rst
> > This will improve consistency, safety, and makes it easier to maintain
> > and update in future.
> >
> > Signed-off-by: Rujra Bhatt <braker.noob.kernel@gmail.com>
> > ---
> >  arch/arc/kernel/perf_event.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
> > index ed6d4f0cd621..424ec072c441 100644
> > --- a/arch/arc/kernel/perf_event.c
> > +++ b/arch/arc/kernel/perf_event.c
> > @@ -648,7 +648,7 @@ static ssize_t arc_pmu_events_sysfs_show(struct device *dev,
> >         struct perf_pmu_events_attr *pmu_attr;
> >
> >         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
> > -       return sprintf(page, "event=0x%04llx\n", pmu_attr->id);
> > +       return sysfs_emit(page, "event=0x%04llx\n", pmu_attr->id);
> >  }
> >
> >  /*
> > --
> > 2.43.0
> >
> 
> Gentle reminder for the replacement of sprintf() with the sysfs_emit(), kindly
> review it.

Why is this required?  There is no bug in the current code, so no need
to change it at all.  Please just use sysfs_emit() for new sysfs files,
no need to churn the tree and change all existing entries, otherwise we
would have done this a long time ago when we introduced these functions.

thanks,

greg k-h

Re: [PATCH] arc:kernel:perf_event.c : replaced sprintf with sysfs_emit()

[Rujra Bhatt]

On Fri, Jul 18, 2025 at 5:18 PM Greg KH <greg@kroah.com> wrote:
>
> On Fri, Jul 18, 2025 at 03:57:20PM +0530, Rujra Bhatt wrote:
> > Hi,
> >
> > On Sat, Jul 5, 2025 at 1:00 PM Rujra Bhatt <braker.noob.kernel@gmail.com> wrote:
> > >
> > > Replaced sprintf() with sysfs_emit() in sysfs*_show() function in
> > > perf_event.c file to follow the kernel's guidelines from
> > > documentation/filesystems/sysfs.rst
> > > This will improve consistency, safety, and makes it easier to maintain
> > > and update in future.
> > >
> > > Signed-off-by: Rujra Bhatt <braker.noob.kernel@gmail.com>
> > > ---
> > >  arch/arc/kernel/perf_event.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
> > > index ed6d4f0cd621..424ec072c441 100644
> > > --- a/arch/arc/kernel/perf_event.c
> > > +++ b/arch/arc/kernel/perf_event.c
> > > @@ -648,7 +648,7 @@ static ssize_t arc_pmu_events_sysfs_show(struct device *dev,
> > >         struct perf_pmu_events_attr *pmu_attr;
> > >
> > >         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
> > > -       return sprintf(page, "event=0x%04llx\n", pmu_attr->id);
> > > +       return sysfs_emit(page, "event=0x%04llx\n", pmu_attr->id);
> > >  }
> > >
> > >  /*
> > > --
> > > 2.43.0
> > >
> >
> > Gentle reminder for the replacement of sprintf() with the sysfs_emit(), kindly
> > review it.
>
> Why is this required?  There is no bug in the current code, so no need
> to change it at all.  Please just use sysfs_emit() for new sysfs files,
> no need to churn the tree and change all existing entries, otherwise we
> would have done this a long time ago when we introduced these functions.
>

Hi Greg,
I appreciate your feedback.

I wanted to bring the formatting in line with the
latest guidance, especially since sysfs_emit() has become the recommended
method for sysfs output. I see now, though, that I should restrict myself to
using that helper only in the context of genuine bug fixes or in the course
of adding features.
I'll make sure to only use sysfs_emit() for new sysfs entries or when
modifying existing files for actual bugs or feature changes,
as per your guidance.

Thank you so much for pointing this out.

regards,
Rujra Bhatt