nvme-pci: check for NULL return from pci_alloc_p2pmem()

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.

Makes sure not to call pci_free_p2pmem() if pci_alloc_p2pmem() returned
NULL, which can happen if CONFIG_PCI_P2PDMA is not configured.

The current implementation is not expected to leak since
pci_p2pmem_virt_to_bus() is expected to fail only if pci_alloc_p2pmem()
returns null. However, checking the return value of pci_alloc_p2pmem()
is more explicit.

Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0423ddd97f4b5a42a3d0d8b49d1a1b2c1c702cf0..ac2011b8dac11e2077408416c5f7afd0ccdf87ae 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1439,11 +1439,15 @@ 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));
                }
        }