fs/lock: Don't allocate file_lock in flock_make_lock().
Two functions, flock syscall and locks_remove_flock(), call
flock_make_lock(). It allocates struct file_lock from slab
cache if its argument fl is NULL.
When we call flock syscall, we pass NULL to allocate memory
for struct file_lock. However, we always free it at the end
by locks_free_lock(). We need not allocate it and instead
should use a local variable as locks_remove_flock() does.
Also, the validation for flock_translate_cmd() is not necessary
for locks_remove_flock(). So we move the part to flock syscall
and make flock_make_lock() return nothing.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>