Re: [PATCH] nvme-pci: Avoid leak if pci_p2pmem_virt_to_bus() returns null

[Heitke, Kenneth]

On 6/24/2019 5:57 PM, Alan Mikhak wrote:

Modify nvme_alloc_sq_cmds() to call pci_free_p2pmem()
to free the memory it allocated using pci_alloc_p2pmem()
in case pci_p2pmem_virt_to_bus() returns null.

Make sure not to call pci_free_p2pmem() if pci_alloc_p2pmem()
returned null which can happen if CONFIG_PCI_P2PDMA is not
configured.

Signed-off-by: Alan Mikhak <alan.mik...@sifive.com>
---
  drivers/nvme/host/pci.c | 14 +++++++++-----
  1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 524d6bd6d095..5dfa067f6506 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1456,11 +1456,15 @@ static int nvme_alloc_sq_cmds(struct nvme_dev *dev, 
struct nvme_queue *nvmeq,

if (qid && dev->cmb_use_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {

                nvmeq->sq_cmds = pci_alloc_p2pmem(pdev, SQ_SIZE(depth));
-               nvmeq->sq_dma_addr = pci_p2pmem_virt_to_bus(pdev,
-                                               nvmeq->sq_cmds);
-               if (nvmeq->sq_dma_addr) {
-                       set_bit(NVMEQ_SQ_CMB, &nvmeq->flags);
-                       return 0;
+               if (nvmeq->sq_cmds) {
+                       nvmeq->sq_dma_addr = pci_p2pmem_virt_to_bus(pdev,
+                                                       nvmeq->sq_cmds);
+                       if (nvmeq->sq_dma_addr) {
+                               set_bit(NVMEQ_SQ_CMB, &nvmeq->flags);
+                               return 0;
+                       }
+
+                       pci_free_p2pmem(pdev, nvmeq->sq_cmds, SQ_SIZE(depth));

Should the pointer be set to NULL here, just in case?

                }
        }