[PATCH] nvme-pci: fix dbbuf_sq_db point to freed memory

[Lulina (A)]

The case is that nvme device support NVME_CTRL_OACS_DBBUF_SUPP, and
return failed when the driver sent nvme_admin_dbbuf. The nvmeq->dbbuf_sq_db
point to freed memory, as nvme_dbbuf_set is called behind nvme_dbbuf_init.

Change-Id: Ief2a5877cb008d3c29cf99053f80fecc9b8db1db
Signed-off-by: lulina <lina.lulina@xxxxxxxxxx>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index da39729..2e11980 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -240,16 +240,25 @@ static int nvme_dbbuf_dma_alloc(struct nvme_dev *dev)
 static void nvme_dbbuf_dma_free(struct nvme_dev *dev)
 {
 	unsigned int mem_size = nvme_dbbuf_size(dev->db_stride);
+	unsigned int i;
 
 	if (dev->dbbuf_dbs) {
 		dma_free_coherent(dev->dev, mem_size,
 				  dev->dbbuf_dbs, dev->dbbuf_dbs_dma_addr);
 		dev->dbbuf_dbs = NULL;
+		for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+			dev->queues[i]->dbbuf_sq_db = NULL;
+			dev->queues[i]->dbbuf_cq_db = NULL;
+		}
 	}
 	if (dev->dbbuf_eis) {
 		dma_free_coherent(dev->dev, mem_size,
 				  dev->dbbuf_eis, dev->dbbuf_eis_dma_addr);
 		dev->dbbuf_eis = NULL;
+		for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+			dev->queues[i]->dbbuf_sq_ei = NULL;
+			dev->queues[i]->dbbuf_cq_ei = NULL;
+		}
 	}
 }
 
-- 
1.8.3.1