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Index: head/sys/kern/subr_witness.c
===================================================================
--- head/sys/kern/subr_witness.c
+++ head/sys/kern/subr_witness.c
@@ -132,9 +132,6 @@
#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */
#define LI_NORELEASE 0x00020000 /* Lock not allowed to be released. */
-/* Define this to check for blessed mutexes */
-#undef BLESSING
-
#ifndef WITNESS_COUNT
#define WITNESS_COUNT 1536
#endif
@@ -278,12 +275,10 @@
u_int wloh_count;
};
-#ifdef BLESSING
struct witness_blessed {
const char *b_lock1;
const char *b_lock2;
};
-#endif
struct witness_pendhelp {
const char *wh_type;
@@ -318,9 +313,7 @@
static int _isitmyx(struct witness *w1, struct witness *w2, int rmask,
const char *fname);
static void adopt(struct witness *parent, struct witness *child);
-#ifdef BLESSING
static int blessed(struct witness *, struct witness *);
-#endif
static void depart(struct witness *w);
static struct witness *enroll(const char *description,
struct lock_class *lock_class);
@@ -726,14 +719,25 @@
{ NULL, NULL }
};
-#ifdef BLESSING
/*
- * Pairs of locks which have been blessed
- * Don't complain about order problems with blessed locks
+ * Pairs of locks which have been blessed. Witness does not complain about
+ * order problems with blessed lock pairs. Please do not add an entry to the
+ * table without an explanatory comment.
*/
static struct witness_blessed blessed_list[] = {
+ /*
+ * See the comment in ufs_dirhash.c. Basically, a vnode lock serializes
+ * both lock orders, so a deadlock cannot happen as a result of this
+ * LOR.
+ */
+ { "dirhash", "bufwait" },
+
+ /*
+ * A UFS vnode may be locked in vget() while a buffer belonging to the
+ * parent directory vnode is locked.
+ */
+ { "ufs", "bufwait" },
};
-#endif
/*
* This global is set to 0 once it becomes safe to use the witness code.
@@ -1339,7 +1343,6 @@
* We have a lock order violation, check to see if it
* is allowed or has already been yelled about.
*/
-#ifdef BLESSING
/*
* If the lock order is blessed, just bail. We don't
@@ -1348,7 +1351,6 @@
*/
if (blessed(w, w1))
goto out;
-#endif
/* Bail if this violation is known */
if (w_rmatrix[w1->w_index][w->w_index] & WITNESS_REVERSAL)
@@ -2084,7 +2086,6 @@
__func__));
}
-#ifdef BLESSING
static int
blessed(struct witness *w1, struct witness *w2)
{
@@ -2104,7 +2105,6 @@
}
return (0);
}
-#endif
static struct witness *
witness_get(void)

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