commit 852b70eca145437991a22f862baccf67fe21ecd7
Author: Jens Axboe <axboe@kernel.dk>
Date:   Tue Feb 15 14:33:50 2022 -0700

    apple-nvme: serialize command issue

    Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index 56a3d05cd8bc..06f77adfc3b7 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -189,6 +189,8 @@ struct apple_nvme {
 	struct nvme_ctrl ctrl;
 	struct work_struct remove_work;

+	spinlock_t sq_lock;
+
 	struct apple_nvme_queue adminq;
 	struct apple_nvme_queue ioq;

@@ -309,7 +311,9 @@ static void apple_nvme_submit_cmd(struct apple_nvme_queue *q,
 		tcb->dma_flags |= APPLE_ANS_TCB_DMA_FROM_DEVICE;

 	memcpy(&q->sqes[tag], cmd, sizeof(*cmd));
+	spin_lock(&anv->sq_lock);
 	writel(tag, q->sq_db);
+	spin_unlock(&anv->sq_lock);
 }

 /*
@@ -1350,6 +1354,7 @@ static int apple_nvme_probe(struct platform_device *pdev)
 	INIT_WORK(&anv->ctrl.reset_work, apple_nvme_reset_work);
 	INIT_WORK(&anv->remove_work, apple_nvme_remove_dead_ctrl_work);
 	spin_lock_init(&anv->lock);
+	spin_lock_init(&anv->sq_lock);

 	ret = apple_nvme_queue_alloc(anv, &anv->adminq);
 	if (ret)