From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Akinobu Mita <akinobu.mita@gmail.com>
Cc: linux-leds@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>
Subject: Re: [PATCH 1/5] leds: remove PAGE_SIZE limit of /sys/class/leds/<led>/trigger
Date: Wed, 11 Sep 2019 16:36:02 +0100 [thread overview]
Message-ID: <20190911153602.GB13865@kroah.com> (raw)
In-Reply-To: <CAC5umyhZ_-Gdh7+EzNoHPs2zki2-dK1xBv5xpE5zwZPt_jvNEA@mail.gmail.com>
On Thu, Sep 12, 2019 at 12:25:28AM +0900, Akinobu Mita wrote:
> 2019年9月8日(日) 22:10 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
> >
> > On Sun, Sep 08, 2019 at 09:41:08PM +0900, Akinobu Mita wrote:
> > > Reading /sys/class/leds/<led>/trigger returns all available LED triggers.
> > > However, the size of this file is limited to PAGE_SIZE because of the
> > > limitation for sysfs attribute.
> > >
> > > Enabling LED CPU trigger on systems with thousands of CPUs easily hits
> > > PAGE_SIZE limit, and makes it impossible to see all available LED triggers
> > > and which trigger is currently activated.
> > >
> > > This converts /sys/class/leds/<led>/trigger to bin attribute and removes
> > > the PAGE_SIZE limitation.
> > >
> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > > Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
> > > Cc: Pavel Machek <pavel@ucw.cz>
> > > Cc: Dan Murphy <dmurphy@ti.com>
> > > Acked-by: Pavel Machek <pavel@ucw.cz>
> > > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> > > ---
> > > drivers/leds/led-class.c | 8 ++--
> > > drivers/leds/led-triggers.c | 90 ++++++++++++++++++++++++++++++++++-----------
> > > drivers/leds/leds.h | 6 +++
> > > include/linux/leds.h | 5 ---
> > > 4 files changed, 79 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> > > index 4793e77..8b5a1d1 100644
> > > --- a/drivers/leds/led-class.c
> > > +++ b/drivers/leds/led-class.c
> > > @@ -73,13 +73,13 @@ static ssize_t max_brightness_show(struct device *dev,
> > > static DEVICE_ATTR_RO(max_brightness);
> > >
> > > #ifdef CONFIG_LEDS_TRIGGERS
> > > -static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
> > > -static struct attribute *led_trigger_attrs[] = {
> > > - &dev_attr_trigger.attr,
> > > +static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
> >
> > BIN_ATTR_RW()?
>
> We can use BIN_ATTR_RW() by renaming led_trigger_{read,write}() to
> trigger_{read,write}(). But led_trigger_{read,write}() are not static
> functions. These are defined as export symbols for led-class module.
>
> So trigger_{read,write}() will be too generic symbol names, won't they?
Yes they would, sorry I didn't notice that.
Wait, why are those functions being exported? Who is calling a sysfs
function from a different code path than sysfs?
thanks,
greg k-h
next prev parent reply other threads:[~2019-09-11 15:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-08 12:41 [PATCH 0/5] leds: fix /sys/class/leds/<led>/trigger and add new api Akinobu Mita
2019-09-08 12:41 ` [PATCH 1/5] leds: remove PAGE_SIZE limit of /sys/class/leds/<led>/trigger Akinobu Mita
2019-09-08 13:10 ` Greg Kroah-Hartman
2019-09-11 15:25 ` Akinobu Mita
2019-09-11 15:36 ` Greg Kroah-Hartman [this message]
2019-09-11 17:25 ` Akinobu Mita
2019-09-08 13:18 ` Greg Kroah-Hartman
2019-09-08 12:41 ` [PATCH 2/5] leds: make sure leds_class is initialized before triggers are registered Akinobu Mita
2019-09-08 13:07 ` Greg Kroah-Hartman
2019-09-08 12:41 ` [PATCH 3/5] driver core: class: add function to create /sys/class/<class>/foo directory Akinobu Mita
2019-09-08 13:08 ` Greg Kroah-Hartman
2019-09-08 13:11 ` Greg Kroah-Hartman
2019-09-08 20:26 ` Pavel Machek
2019-09-08 12:41 ` [PATCH 4/5] leds: add /sys/class/triggers/ that contains trigger sub-directories Akinobu Mita
2019-09-08 13:21 ` Greg Kroah-Hartman
2019-09-08 12:41 ` [PATCH 5/5] leds: add /sys/class/leds/<led>/current-trigger Akinobu Mita
2019-09-08 13:10 ` Greg Kroah-Hartman
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