Buddy: copy the priority from reqs to i_wait

otherwise all hell will break loose if we changed reqs->pri, because
we would dequeue from the wrong list head.

src/buddy.c

@@ -1663,11 +1663,12 @@ buddy_reqs_enqueue(struct buddy_reqs *reqs)
 	assert(w->state == IW_ARMED);
 	w->state = IW_WAITING;
 	assert(reqs->pri <= BUDDY_WAIT_MAXPRI);
-	VTAILQ_INSERT_TAIL(&buddy->reqs_head[reqs->pri], reqs, i_wait.list);
+	w->pri = reqs->pri;
+	VTAILQ_INSERT_TAIL(&buddy->reqs_head[w->pri], reqs, i_wait.list);
 	buddy->waiting++;
 	buddy->deficit += reqs->sz;
-	if (reqs->pri > buddy->wait_pri)
-		buddy->wait_pri = reqs->pri;
+	if (w->pri > buddy->wait_pri)
+		buddy->wait_pri = w->pri;
 	AZ(pthread_cond_broadcast(&buddy->wait_kick_cond));
 }
 
@@ -1722,7 +1723,7 @@ buddy_reqs_wait_cancel(struct buddy_reqs *reqs)
 	if (w->state == IW_WAITING) {
 		/* remove from wait list, w->state could be outdated ! */
 		buddy = reqs->buddy;
-		head = &buddy->reqs_head[reqs->pri];
+		head = &buddy->reqs_head[w->pri];
 
 		AZ(pthread_mutex_lock(&reqs->buddy->map_mtx));
 		AZ(pthread_mutex_lock(&w->wait_mtx));
@@ -1736,7 +1737,7 @@ buddy_reqs_wait_cancel(struct buddy_reqs *reqs)
 			VTAILQ_REMOVE(head, reqs, i_wait.list);
 			w->state = IW_SIGNALLED;
 		}
-		if (buddy->waiting && buddy->wait_pri == reqs->pri)
+		if (buddy->waiting && buddy->wait_pri == w->pri)
 			buddy_wait_work(buddy);
 		AZ(pthread_mutex_unlock(&reqs->buddy->map_mtx));
 	} else {

src/buddy.h

@@ -303,6 +303,7 @@ struct i_wait {
 	pthread_cond_t			wait_cond;
 	VTAILQ_ENTRY(buddy_reqs)	list;
 	// updated under lock - KEEP SEPERATE FROM "owned by initiator"
+	uint8_t				pri; // index to head for list
 	uint8_t				alloced; // how many of n
 	enum i_wait_state		state;
 };