7351 NVMe driver sporadically lost track of completed I/O request, which
leads to zpool hanging and machine panic.

@@ -96,10 +96,13 @@
         uint16_t nq_next_cmd;
         uint_t nq_active_cmds;
         int nq_phase;
 
         kmutex_t nq_mutex;
+        hrtime_t nq_ts;
+        list_node_t nq_list_node;
+        nvme_t *nq_nvme;
 };
 
 struct nvme {
         dev_info_t *n_dip;
         int n_progress;

@@ -114,10 +117,11 @@
         int n_intr_cnt;
         uint_t n_intr_pri;
         int n_intr_cap;
         int n_intr_type;
         int n_intr_types;
+        int n_intr_timeouts;
 
         char *n_product;
         char *n_vendor;
 
         boolean_t n_dead;