[PATCH v4 0/2] proc,fcntl: introduce F_SET_DESCRIPTION

[Pascal Bouchareine]

This is a first attempt at taking Alexey's comments into account

This goes against v5.8

tl;dr in commit 2/2 but motivation is also described a bit in
https://lore.kernel.org/linux-api/CAGbU3_nVvuzMn2wo4_ZKufWcGfmGsopVujzTWw-Bbeky=xS+GA@xxxxxxxxxxxxxx/