XFS Kconfig variable XFS_TRACE not defined anywhere

[Christoph Hellwig]

On Sun, Jun 19, 2011 at 07:24:46AM -0400, Robert P. J. Day wrote:
> 
>   just FYI:
> 
> ===== XFS_TRACE =====
> ./fs/xfs/Makefile:xfs-$(CONFIG_XFS_TRACE)		+= xfs_btree_trace.o
> 
>   as far as i can tell, there is no definition of the Kconfig variable
> XFS_TRACE, so that Makefile entry is redundant.

It's part of the old kdb-only tracing implementation and now dead.  We
left it in as a reminder to still convert the btree tracing code to
trace events once the technology for it becomes awailable.  At this
point I suspect we could simply remove it as we still have the code
available in git history.  And xfs_btree_trace.c itself doesn't contain
any interesting code anyway as the interesting bits are in the macros
which we are going to keep anyway.