net: hns3: use atomic_t replace u32 for arq's count

Since irq handler and mailbox task will both update arq's count,
so arq's count should use atomic_t instead of u32, otherwise
its value may go wrong finally.

Fixes: 07a0556a3a ("net: hns3: Changes to support ARQ(Asynchronous Receive Queue)")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hclge_mbx.h

@@ -111,7 +111,7 @@ struct hclgevf_mbx_arq_ring {
 	struct hclgevf_dev *hdev;
 	u32 head;
 	u32 tail;
-	u32 count;
+	atomic_t count;
 	u16 msg_q[HCLGE_MBX_MAX_ARQ_MSG_NUM][HCLGE_MBX_MAX_ARQ_MSG_SIZE];
 };
 

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_cmd.c

@@ -340,7 +340,7 @@ int hclgevf_cmd_init(struct hclgevf_dev *hdev)
 	hdev->arq.hdev = hdev;
 	hdev->arq.head = 0;
 	hdev->arq.tail = 0;
-	hdev->arq.count = 0;
+	atomic_set(&hdev->arq.count, 0);
 	hdev->hw.cmq.csq.next_to_clean = 0;
 	hdev->hw.cmq.csq.next_to_use = 0;
 	hdev->hw.cmq.crq.next_to_clean = 0;

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_mbx.c

@@ -212,7 +212,8 @@ void hclgevf_mbx_handler(struct hclgevf_dev *hdev)
 			/* we will drop the async msg if we find ARQ as full
 			 * and continue with next message
 			 */
-			if (hdev->arq.count >= HCLGE_MBX_MAX_ARQ_MSG_NUM) {
+			if (atomic_read(&hdev->arq.count) >=
+			    HCLGE_MBX_MAX_ARQ_MSG_NUM) {
 				dev_warn(&hdev->pdev->dev,
 					 "Async Q full, dropping msg(%d)\n",
 					 req->msg[1]);
@@ -224,7 +225,7 @@ void hclgevf_mbx_handler(struct hclgevf_dev *hdev)
 			memcpy(&msg_q[0], req->msg,
 			       HCLGE_MBX_MAX_ARQ_MSG_SIZE * sizeof(u16));
 			hclge_mbx_tail_ptr_move_arq(hdev->arq);
-			hdev->arq.count++;
+			atomic_inc(&hdev->arq.count);
 
 			hclgevf_mbx_task_schedule(hdev);
 
@@ -317,7 +318,7 @@ void hclgevf_mbx_async_handler(struct hclgevf_dev *hdev)
 		}
 
 		hclge_mbx_head_ptr_move_arq(hdev->arq);
-		hdev->arq.count--;
+		atomic_dec(&hdev->arq.count);
 		msg_q = hdev->arq.msg_q[hdev->arq.head];
 	}
 }