Use cond_resched() instead of yield() in the loop of
nilfs_transaction_lock() since the usage corresponds to the "be nice for
others" case that the comment of yield() says.
This removes the following checkpatch.pl warning:
 "WARNING: Using yield() is generally wrong. See yield() kernel-doc
  (sched/core.c)"
Link: http://lkml.kernel.org/r/1464875891-5443-8-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
                nilfs_segctor_do_immediate_flush(sci);
 
                up_write(&nilfs->ns_segctor_sem);
-               yield();
+               cond_resched();
        }
        if (gcflag)
                ti->ti_flags |= NILFS_TI_GC;