[BUG] fs/f2fs: a possible sleep-in-atomic bug in f2fs_trace_pid

[Jia-Ju Bai]

According to fs/f2fs/trace.c, the kernel module may sleep under a spinlock.
The function call path is:
f2fs_trace_pid (acquire the spinlock)
  f2fs_radix_tree_insert
    cond_resched --> may sleep

I do not find a good way to fix it, so I only report.
This possible bug is found by my static analysis tool (DSAC) and my code 
review.


Thanks,
Jia-Ju Bai