Attached is a cleanup of fs/pipe.c, against 2.5.14-dj2.

Main changes:
* 50 lines shorter
* fifo open now runs without the big kernel lock. The code didn't rely
on the blk since ~2.3.52.
* only update mtime, atime, ctime if a nonzero amount of data was
transfered.
* enable syscall merging for O_NONBLOCK pipe_read.
* fix a race that could trigger a wakeup storm if multiple threads read
from the same pipe.

The patch doesn't apply to 2.5.15 due to the fasync support.
--	
	Manfred