On Fri 2019-03-29 07:22:53, Greg Kroah-Hartman wrote: > On Fri, Mar 29, 2019 at 04:09:22AM +0100, Marek Behun wrote: > > Hello Tejun and Greg, > > > > kernfs_fop_open/read/write allocates a buffer for the ->read, ->write, > > or ->seq_read methods. This buffer is either preallocated or allocated > > on the spot, with minimum size being PAGE_SIZE, if ->atomic_write_len > > is not given. > > > > There is a question/problem currently in the led-trigger API, that the > > PAGE_SIZE buffer can in some specific scenarios be too short. > > And that file is in sysfs? That's a huge abuse of the sysfs api > then :(
Yes, that's how we do selection from the list in sysfs, and
led-trigger is not alone there:
pavel@amd:~/cip$ cat /sys/power/state
freeze mem disk
pavel@amd:~/cip$ cat /sys/class/leds/phy0-led/trigger
none bluetooth-power rfkill-any rfkill-none kbd-scrolllock kbd-numlock
kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock
kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock
AC-online BAT0-charging-or-full BAT0-charging BAT0-full
BAT0-charging-blink-full-solid rfkill0 phy0rx phy0tx phy0assoc
phy0radio [phy0tpt] mmc0 timer heartbeat audio-mute audio-micmute
rfkill1 hci0-power rfkill8
pavel@amd:~/cip$
Now problem is that list grew long over time... and it is too late to
change the API now (and alternatives seem worse than present
solution).
Pavel
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