lockmgr keeps losing code, call 911!

ok pedro@ art@

1 files changed, 8 insertions, 66 deletions

diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c
index d0b418a7b1f..6d51847a770 100644
--- a/sys/kern/kern_lock.c
+++ b/sys/kern/kern_lock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_lock.c,v 1.25 2007/03/15 10:22:30 art Exp $	*/
+/*	$OpenBSD: kern_lock.c,v 1.26 2007/04/11 12:06:37 miod Exp $	*/
 
 /* 
  * Copyright (c) 1995
@@ -287,7 +287,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 			 * If just polling, check to see if we will block.
 			 */
 			if ((extflags & LK_NOWAIT) && (lkp->lk_flags &
-			    (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE))) {
+			    (LK_HAVE_EXCL | LK_WANT_EXCL))) {
 				error = EBUSY;
 				break;
 			}
@@ -295,7 +295,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 			 * Wait for exclusive locks and upgrades to clear.
 			 */
 			ACQUIRE(lkp, error, extflags, 0, lkp->lk_flags &
-			    (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE));
+			    (LK_HAVE_EXCL | LK_WANT_EXCL));
 			if (error)
 				break;
 			lkp->lk_sharecount++;
@@ -308,9 +308,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 		 */
 		lkp->lk_sharecount++;
 		COUNT(lkp, p, cpu_id, 1);
-		/* FALLTHROUGH */
 
-	case LK_DOWNGRADE:
 		if (WEHOLDIT(lkp, pid, cpu_id) == 0 ||
 		    lkp->lk_exclusivecount == 0)
 			panic("lockmgr: not holding exclusive lock");
@@ -326,61 +324,6 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 		WAKEUP_WAITER(lkp);
 		break;
 
-	case LK_UPGRADE:
-		/*
-		 * Upgrade a shared lock to an exclusive one. If another
-		 * shared lock has already requested an upgrade to an
-		 * exclusive lock, our shared lock is released and an
-		 * exclusive lock is requested (which will be granted
-		 * after the upgrade). If we return an error, the file
-		 * will always be unlocked.
-		 */
-		if (WEHOLDIT(lkp, pid, cpu_id) || lkp->lk_sharecount <= 0)
-			panic("lockmgr: upgrade exclusive lock");
-		lkp->lk_sharecount--;
-		COUNT(lkp, p, cpu_id, -1);
-		/*
-		 * If we are just polling, check to see if we will block.
-		 */
-		if ((extflags & LK_NOWAIT) &&
-		    ((lkp->lk_flags & LK_WANT_UPGRADE) ||
-		     lkp->lk_sharecount > 1)) {
-			error = EBUSY;
-			break;
-		}
-		if ((lkp->lk_flags & LK_WANT_UPGRADE) == 0) {
-			/*
-			 * We are first shared lock to request an upgrade, so
-			 * request upgrade and wait for the shared count to
-			 * drop to zero, then take exclusive lock.
-			 */
-			lkp->lk_flags |= LK_WANT_UPGRADE;
-			ACQUIRE(lkp, error, extflags, 0, lkp->lk_sharecount);
-			lkp->lk_flags &= ~LK_WANT_UPGRADE;
-			if (error)
-				break;
-			lkp->lk_flags |= LK_HAVE_EXCL;
-			SETHOLDER(lkp, pid, cpu_id);
-#if defined(LOCKDEBUG)
-			lkp->lk_lock_file = file;
-			lkp->lk_lock_line = line;
-#endif
-			HAVEIT(lkp);
-			if (lkp->lk_exclusivecount != 0)
-				panic("lockmgr: non-zero exclusive count");
-			lkp->lk_exclusivecount = 1;
-			COUNT(lkp, p, cpu_id, 1);
-			break;
-		}
-		/*
-		 * Someone else has requested upgrade. Release our shared
-		 * lock, awaken upgrade requestor if we are the last shared
-		 * lock, then request an exclusive lock.
-		 */
-		if (lkp->lk_sharecount == 0)
-			WAKEUP_WAITER(lkp);
-		/* FALLTHROUGH */
-
 	case LK_EXCLUSIVE:
 		if (WEHOLDIT(lkp, pid, cpu_id)) {
 			/*
@@ -401,7 +344,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 		 * If we are just polling, check to see if we will sleep.
 		 */
 		if ((extflags & LK_NOWAIT) && ((lkp->lk_flags &
-		     (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) ||
+		     (LK_HAVE_EXCL | LK_WANT_EXCL)) ||
 		     lkp->lk_sharecount != 0)) {
 			error = EBUSY;
 			break;
@@ -417,8 +360,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 		/*
 		 * Wait for shared locks and upgrades to finish.
 		 */
-		ACQUIRE(lkp, error, extflags, 0, lkp->lk_sharecount != 0 ||
-		       (lkp->lk_flags & LK_WANT_UPGRADE));
+		ACQUIRE(lkp, error, extflags, 0, lkp->lk_sharecount != 0);
 		lkp->lk_flags &= ~LK_WANT_EXCL;
 		if (error)
 			break;
@@ -477,14 +419,14 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 		 * If we are just polling, check to see if we will sleep.
 		 */
 		if ((extflags & LK_NOWAIT) && ((lkp->lk_flags &
-		     (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) ||
+		     (LK_HAVE_EXCL | LK_WANT_EXCL)) ||
 		     lkp->lk_sharecount != 0 || lkp->lk_waitcount != 0)) {
 			error = EBUSY;
 			break;
 		}
 		ACQUIRE(lkp, error, extflags, 1,
 		    ((lkp->lk_flags &
-		     (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) ||
+		     (LK_HAVE_EXCL | LK_WANT_EXCL)) ||
 		     lkp->lk_sharecount != 0 ||
 		     lkp->lk_waitcount != 0));
 		if (error)
@@ -508,7 +450,7 @@ lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp)
 	}
 	if ((lkp->lk_flags & LK_WAITDRAIN) != 0 &&
 	    ((lkp->lk_flags &
-	    (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) == 0 &&
+	    (LK_HAVE_EXCL | LK_WANT_EXCL)) == 0 &&
 	    lkp->lk_sharecount == 0 && lkp->lk_waitcount == 0)) {
 		lkp->lk_flags &= ~LK_WAITDRAIN;
 		wakeup((void *)&lkp->lk_flags);