RDMA/efa: Count admin commands errors

Add a new stat that counts admin commands failures, which might help when
debugging different issues.

Link: https://lore.kernel.org/r/20200420062213.44577-4-galpress@amazon.com
Reviewed-by: Daniel Kranzdorf <dkkranzd@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/efa/efa_com.c

@@ -631,17 +631,20 @@ int efa_com_cmd_exec(struct efa_com_admin_queue *aq,
 			cmd->aq_common_descriptor.opcode, PTR_ERR(comp_ctx));
 
 		up(&aq->avail_cmds);
+		atomic64_inc(&aq->stats.cmd_err);
 		return PTR_ERR(comp_ctx);
 	}
 
 	err = efa_com_wait_and_process_admin_cq(comp_ctx, aq);
-	if (err)
+	if (err) {
 		ibdev_err_ratelimited(
 			aq->efa_dev,
 			"Failed to process command %s (opcode %u) comp_status %d err %d\n",
 			efa_com_cmd_str(cmd->aq_common_descriptor.opcode),
 			cmd->aq_common_descriptor.opcode, comp_ctx->comp_status,
 			err);
+		atomic64_inc(&aq->stats.cmd_err);
+	}
 
 	up(&aq->avail_cmds);