On Tue, Sep 03, 2019 at 10:55:40PM +0900, Akinobu Mita wrote: > 2019年9月3日(火) 4:08 Greg KH <gre...@linuxfoundation.org>: > > > > On Mon, Sep 02, 2019 at 08:47:02PM +0200, Jacek Anaszewski wrote: > > > On 9/2/19 8:12 PM, Greg KH wrote: > > > > On Sun, Sep 01, 2019 at 06:53:34PM +0200, Jacek Anaszewski wrote: > > > >> Hi Akinobu, > > > >> > > > >> Thank you for the patch. > > > >> > > > >> I have one nit below but in general it looks good to me. > > > >> I've tested it with 2000 mtd triggers (~14kB file size) > > > >> and it worked flawlessly. > > > >> > > > >> Still, I would like to have ack from Greg for it. > > > >> > > > >> Adding Greg on Cc. > > > >> > > > >> On 8/29/19 4:49 PM, 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. > > > > > > > > But this is NOT a binary file. A sysfs binary file is used for when the > > > > kernel passes data to or from hardware without any parsing of the data > > > > by the kernel. > > > > > > > > You are not doing that here, you are abusing the "one value per file" > > > > rule of sysfs so much that you are forced to work around the limitation > > > > it put in place on purpose to keep you from doing stuff like this. > > > > > > > > Please fix this "correctly" by creating a new api that works properly > > > > and just live with the fact that this file will never work correctly and > > > > move everyone to use the new api instead. > > > > > > > > Don't keep on abusing the interface by workarounds like this, it is not > > > > ok. > > > > > > In the message [0] you pledged to give us exception for that, provided > > > it will be properly documented in the code. I suppose you now object > > > because the patch does not meet that condition. > > > > Well, I honestly don't remember writing that email, but it was 5 months > > and many thousands of emails ago :) > > > > Also, you all didn't document the heck out of this. So no, I really do > > not want to see this patch accepted as-is. > > > > > Provided that will be fixed, can we count on your ack for the > > > implementation of the solution you proposed? :-) > > > > Let's see the patch that actually implements what I suggested first :) > > I'd propose introducing a new procfs file (/proc/led-triggers) and new > /sys/class/leds/<led>/current-trigger api. > > Reading /proc/led-triggers file shows all available triggers. > This violates "one value per file", but it's a procfs file.
No, procfs files are ONLY for process-related things. Don't keep the insanity of this file format by just moving it out of sysfs and into procfs :) thanks, greg k-h
