SET_FS not supported in Linux 5.15 in openwrt 23.05.02 way forward for alternative to SET_FS

I am working on upstepping openwrt22 to openwrt23.05 where it is with linux 5.15 version.
We have kernel driver modules which use SET_FS feature to read/write files in filesystem but when it is upstep to linux 5.15 version it looks SET_FS feature is removed so could any of the experts in the forum suggest what is the alternative approach to be taken to adapt our drivers with minimal code changes.?

Please post output of

ubus call system board