From: Minwoo Im <minwoo.im.dev@gmail.com>
Date: Thu, 5 Nov 2020 23:28:47 +0900
Subject: nvme: free sq/cq dbbuf pointers when dbbuf set fails
Patch-mainline: v5.10-rc5
Git-commit: 0f0d2c876c96d4908a9ef40959a44bec21bdd6cf
References: git-fixes

If Doorbell Buffer Config command fails even 'dev->dbbuf_dbs != NULL'
which means OACS indicates that NVME_CTRL_OACS_DBBUF_SUPP is set,
nvme_dbbuf_update_and_check_event() will check event even it's not been
successfully set.

This patch fixes mismatch among dbbuf for sq/cqs in case that dbbuf
command fails.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/pci.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -276,9 +276,21 @@ static void nvme_dbbuf_init(struct nvme_
 	nvmeq->dbbuf_cq_ei = &dev->dbbuf_eis[cq_idx(qid, dev->db_stride)];
 }
 
+static void nvme_dbbuf_free(struct nvme_queue *nvmeq)
+{
+	if (!nvmeq->qid)
+		return;
+
+	nvmeq->dbbuf_sq_db = NULL;
+	nvmeq->dbbuf_cq_db = NULL;
+	nvmeq->dbbuf_sq_ei = NULL;
+	nvmeq->dbbuf_cq_ei = NULL;
+}
+
 static void nvme_dbbuf_set(struct nvme_dev *dev)
 {
 	struct nvme_command c;
+	unsigned int i;
 
 	if (!dev->dbbuf_dbs)
 		return;
@@ -292,6 +304,9 @@ static void nvme_dbbuf_set(struct nvme_d
 		dev_warn(dev->ctrl.device, "unable to set dbbuf\n");
 		/* Free memory and continue on */
 		nvme_dbbuf_dma_free(dev);
+
+		for (i = 1; i <= dev->online_queues; i++)
+			nvme_dbbuf_free(&dev->queues[i]);
 	}
 }