davidxu b05094dc42 Use atomic instruction to set _has_writer, otherwise there is a race
causes userland to not wake up a thread sleeping in kernel.

MFC after: 3 days
2010-11-22 02:42:02 +00:00
..
2010-11-08 21:22:55 +00:00
2010-07-12 10:18:10 +00:00
2010-11-20 08:40:37 +00:00
2010-11-09 10:59:09 +00:00