3006 VERIFY[S,U,P] and ASSERT[S,U,P] frequently check if first argument is zero

@@ -272,11 +272,11 @@
         for (i = start; i <= end; i++, bp++) {
                 if (BP_IS_HOLE(bp))
                         continue;
                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
                 err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb);
-                ASSERT3U(err, ==, 0);
+                ASSERT0(err);
                 rw_exit(&dn->dn_struct_rwlock);
 
                 if (free_children(subdb, blkid, nblks, trunc, tx) == ALL) {
                         ASSERT3P(subdb->db_blkptr, ==, bp);
                         blocks_freed += free_blocks(dn, bp, 1, tx);

@@ -292,11 +292,11 @@
         for (i = start; i <= end; i++, bp++) {
                 if (i == start && blkid != 0)
                         continue;
                 else if (i == end && !trunc)
                         continue;
-                ASSERT3U(bp->blk_birth, ==, 0);
+                ASSERT0(bp->blk_birth);
         }
 #endif
         ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
         return (all ? ALL : blocks_freed);
 }

@@ -348,11 +348,11 @@
         for (i = start; i <= end; i++, bp++) {
                 if (BP_IS_HOLE(bp))
                         continue;
                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
                 err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db);
-                ASSERT3U(err, ==, 0);
+                ASSERT0(err);
                 rw_exit(&dn->dn_struct_rwlock);
 
                 if (free_children(db, blkid, nblks, trunc, tx) == ALL) {
                         ASSERT3P(db->db_blkptr, ==, bp);
                         (void) free_blocks(dn, bp, 1, tx);

@@ -469,11 +469,11 @@
 
         /*
          * Our contents should have been freed in dnode_sync() by the
          * free range record inserted by the caller of dnode_free().
          */
-        ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);
+        ASSERT0(DN_USED_BYTES(dn->dn_phys));
         ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
 
         dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
         dnode_evict_dbufs(dn);
         ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);