[XFS] streamline init/exit path

Currently the xfs module init/exit code is a mess. It's farmed out over a
lot of function with very little error checking. This patch makes sure we
propagate all initialization failures properly and clean up after them.
Various runtime initializations are replaced with compile-time
initializations where possible to make this easier. The exit path is
similarly consolidated.

There's now split out function to create/destroy the kmem zones and
alloc/free the trace buffers. I've also changed the ktrace allocations to
KM_MAYFAIL and handled errors resulting from that.

And yes, we really should replace the XFS_*_TRACE ifdefs with a single
XFS_TRACE..

SGI-PV: 976035

SGI-Modid: xfs-linux-melb:xfs-kern:31354a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

fs/xfs/support/uuid.c

@@ -17,7 +17,7 @@
  */
 #include <xfs.h>
 
-static mutex_t	uuid_monitor;
+static DEFINE_MUTEX(uuid_monitor);
 static int	uuid_table_size;
 static uuid_t	*uuid_table;
 
@@ -132,9 +132,3 @@ uuid_table_remove(uuid_t *uuid)
 	ASSERT(i < uuid_table_size);
 	mutex_unlock(&uuid_monitor);
 }
-
-void __init
-uuid_init(void)
-{
-	mutex_init(&uuid_monitor);
-}