This commit refactored the implementation of TIOCGPTPEER, moving "case TIOCGPTPEER" from pty_unix98_ioctl() to tty_ioctl(). pty_unix98_ioctl() is called by pty_unix98_compat_ioctl(), so before the commit, TIOCGPTPEER worked for 32-bit userspace. Unfortunately tty_compat_ioctl() does not call tty_ioctl() so after the commit, TIOCGPTPEER from 32-bit userspace fails with ENOTTY.
Testcase in https://bugzilla.kernel.org/show_bug.cgi?id=202271. I found this bug running the rr test suite. Rob -- Su ot deraeppa sah dna Rehtaf eht htiw saw hcihw, efil lanrete eht uoy ot mialcorp ew dna, ti ot yfitset dna ti nees evah ew; deraeppa efil eht. Efil fo Drow eht gninrecnoc mialcorp ew siht - dehcuot evah sdnah ruo dna ta dekool evah ew hcihw, seye ruo htiw nees evah ew hcihw, draeh evah ew hcihw, gninnigeb eht morf saw hcihw taht.
