Lots of fixes here:

- Detailed kmem memory allocation tracking.  We can now get on
  spl module unload a list of all memory allocations which were
  not free'd and where the original alloc was.  E.g.

SPL: 15554:632:(spl-kmem.c:442:kmem_fini()) kmem leaked 90/319332 bytes
SPL: 15554:648:(spl-kmem.c:451:kmem_fini()) address          size  data             func:line
SPL: 15554:648:(spl-kmem.c:457:kmem_fini()) ffff8100734b68b8 32    0100000001005a5a __spl_mutex_init:70
SPL: 15554:648:(spl-kmem.c:457:kmem_fini()) ffff8100734b6148 13    &tl->tl_lock     __spl_mutex_init:74
SPL: 15554:648:(spl-kmem.c:457:kmem_fini()) ffff81007ac43730 32    0100000001005a5a __spl_mutex_init:70
SPL: 15554:648:(spl-kmem.c:457:kmem_fini()) ffff81007ac437d8 13    &tl->tl_lock     __spl_mutex_init:74

- Shift to using rwsems in kmem implmentation, to simply locking and
  improve concurency.

- Shift to using rwsems in mutex implementation, additionally ensure we
  never sleep in the init function if non-zero preempt_count or 
  interrupts are disabled as can happen in a slab cache ctor/dtor.

- Other minor formating fixes and such.

TODO:

- Finish the vmem memory allocation tracking

- Vet all other SPL primatives for potential sleeping during *_init.  I
suspect the rwlock implemenation does this and should be fixes just
like the mutex implemenation.



git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@95 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c

modules/spl/spl-proc.c

@@ -426,7 +426,7 @@ mutex_seq_start(struct seq_file *f, loff_t *pos)
         loff_t n = *pos;
         ENTRY;
 
-        mutex_lock(&mutex_stats_lock);
+        down_read(&mutex_stats_sem);
         if (!n)
                 mutex_seq_show_headers(f);
 
@@ -454,7 +454,7 @@ mutex_seq_next(struct seq_file *f, void *p, loff_t *pos)
 static void
 mutex_seq_stop(struct seq_file *f, void *v)
 {
-        mutex_unlock(&mutex_stats_lock);
+        up_read(&mutex_stats_sem);
 }
 
 static struct seq_operations mutex_seq_ops = {