Modify the critical section API as follows:

- The MD functions critical_enter/exit are renamed to start with a cpu_
  prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
  count and a per-thread critical section saved state set when entering
  a critical section while at nesting level 0 and restored when exiting
  to nesting level 0.  This moves the saved state out of spin mutexes so
  that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
  cpu_critical_enter/exit.  MI code such as device drivers and spin
  mutexes use the MI wrappers.  Note that since the MI wrappers store
  the state in the current thread, they do not have any return values or
  arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
  assigned to curthread->td_savecrit during fork_exit().

Tested on:	i386, alpha

1 files changed, 6 insertions, 7 deletions

diff --git a/sys/kern/subr_witness.c b/sys/kern/subr_witness.c
index 454fd55..5e4dc61 100644
--- a/sys/kern/subr_witness.c
+++ b/sys/kern/subr_witness.c
@@ -252,7 +252,6 @@ static struct mtx all_mtx = {
 	  { NULL },			/* mtx_object.lo_list */
 	  NULL },			/* mtx_object.lo_witness */
 	MTX_UNOWNED, 0,			/* mtx_lock, mtx_recurse */
-	0,				/* mtx_savecrit */
 	TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked),
 	{ NULL, NULL }			/* mtx_contested */
 };
@@ -836,7 +835,7 @@ witness_unlock(struct lock_object *lock, int flags, const char *file, int line)
 					instance->li_flags--;
 					goto out;
 				}
-				s = critical_enter();
+				s = cpu_critical_enter();
 				CTR4(KTR_WITNESS,
 				    "%s: pid %d removed %s from lle[%d]", __func__,
 				    td->td_proc->p_pid,
@@ -846,7 +845,7 @@ witness_unlock(struct lock_object *lock, int flags, const char *file, int line)
 				for (j = i; j < (*lock_list)->ll_count; j++)
 					(*lock_list)->ll_children[j] =
 					    (*lock_list)->ll_children[j + 1];
-				critical_exit(s);
+				cpu_critical_exit(s);
 				if ((*lock_list)->ll_count == 0) {
 					lle = *lock_list;
 					*lock_list = lle->ll_next;
@@ -896,7 +895,7 @@ witness_sleep(int check_only, struct lock_object *lock, const char *file,
 	/*
 	 * Preemption bad because we need PCPU_PTR(spinlocks) to not change.
 	 */
-	savecrit = critical_enter();	
+	savecrit = cpu_critical_enter();	
 	td = curthread;
 	lock_list = &td->td_sleeplocks;
 again:
@@ -931,7 +930,7 @@ again:
 	if (witness_ddb && n)
 		Debugger(__func__);
 #endif /* DDB */
-	critical_exit(savecrit);
+	cpu_critical_exit(savecrit);
 	return (n);
 }
 
@@ -1360,9 +1359,9 @@ witness_list(struct thread *td)
 		 * Preemption bad because we need PCPU_PTR(spinlocks) to not
 		 * change.
 		 */
-		savecrit = critical_enter();
+		savecrit = cpu_critical_enter();
 		nheld += witness_list_locks(PCPU_PTR(spinlocks));
-		critical_exit(savecrit);
+		cpu_critical_exit(savecrit);
 	}
 	return (nheld);
 }