fs: use rlimit helpers

Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in commit 3e10e716abf3 ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --cc fs/attr.c
Simple merge

diff --cc fs/binfmt_aout.c
Simple merge

diff --cc fs/binfmt_flat.c
Simple merge

diff --cc fs/exec.c
Simple merge

diff --cc fs/fcntl.c
Simple merge

diff --cc fs/file.c
Simple merge

diff --cc fs/proc/array.c
Simple merge

diff --cc fs/select.c
Simple merge