Pull fscache/cachefiles fixes from David Howells:
- Fix kdoc on fscache_use/unuse_cookie().
- Fix the error returned by cachefiles_ondemand_copen() from an upcall
result.
- Fix the distribution of requests in on-demand mode in cachefiles to
be fairer by cycling through them rather than picking the one with
the lowest ID each time (IDs being reused).
* tag 'fscache-fixes-
20220831' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
cachefiles: make on-demand request distribution fairer
cachefiles: fix error return code in cachefiles_ondemand_copen()
fscache: fix misdocumented parameter