K 10
svn:author
V 5
kmacy
K 8
svn:date
V 27
2009-05-19T05:36:10.248340Z
K 7
svn:log
V 1509
merge changes to support lockless fget

187677,187682,187693,187996,189708,192080

Fix errors introduced when I rewrote select.
 - Restructure selscan() and selrescan() to avoid producing extra selfps
   when we have a fd in multiple sets.  As described below multiple selfps
   may still exist for other reasons.
 - Make selrescan() tolerate multiple selfds for a given descriptor
   set since sockets use two selinfos per fd.  If an event on each selinfo
   fires selrescan() will see the descriptor twice.  This could result in
   select() returning 2x the number of fds actually existing in fd sets.

Reported by:	mgleason@ncftp.com

- bit has to be fd_mask to work properly on 64bit platforms.  Constants
   must also be cast even though the result ultimately is promoted
   to 64bit.
 - Correct a loop index upper bound in selscan()

Fix select on platforms where sizeof(long) != sizeof(int). This used
to work by accident before the cleanup done in revision 187693.

Approved by:	kan (mentor)

- Implement a lockless file descriptor lookup algorithm in
   fget_unlocked().
 - Save old file descriptor tables created on expansion until
   the entire descriptor table is freed so that pointers may be
   followed without regard for expanders.
 - Mark the file zone as NOFREE so we may attempt to reference
   potentially freed files.
 - Convert several fget_locked() users to fget_unlocked().  This
   requires us to manage reference counts explicitly but reduces
   locking overhead in the common case.

END