[RFC,v2,1/2] vmxnet3: Fix inconsistent DMA accesses in vmxnet3_probe_device()

Commit Message

Brian Johannesmeyer Nov. 19, 2024, 10:13 p.m. UTC

After mapping `adapter` to streaming DMA, but before accessing it,
synchronize it to the CPU. Then, before returning, synchronize it back to
the device. This mitigates any inconsistent accesses to it from
vmxnet3_probe_device().

Co-developed-by: Raphael Isemann <[e-mail]>
Signed-off-by: Raphael Isemann <[e-mail]>
Signed-off-by: Brian Johannesmeyer <[e-mail]>
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 7fa74b8b2100..032d3cd34be1 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -3623,6 +3623,8 @@  vmxnet3_probe_device(struct pci_dev *pdev,
 	int num_rx_queues;
 	int queues;
 	unsigned long flags;
+	struct device *dev;
+	dma_addr_t adapter_pa;
 
 	if (!pci_msi_enabled())
 		enable_mq = 0;
@@ -3662,14 +3664,19 @@  vmxnet3_probe_device(struct pci_dev *pdev,
 	}
 
 	spin_lock_init(&adapter->cmd_lock);
-	adapter->adapter_pa = dma_map_single(&adapter->pdev->dev, adapter,
-					     sizeof(struct vmxnet3_adapter),
-					     DMA_TO_DEVICE);
-	if (dma_mapping_error(&adapter->pdev->dev, adapter->adapter_pa)) {
+	dev = &adapter->pdev->dev;
+	adapter_pa = dma_map_single(dev, adapter,
+				    sizeof(struct vmxnet3_adapter),
+				    DMA_TO_DEVICE);
+	if (dma_mapping_error(dev, adapter_pa)) {
 		dev_err(&pdev->dev, "Failed to map dma\n");
 		err = -EFAULT;
 		goto err_set_mask;
 	}
+	dma_sync_single_for_cpu(dev, adapter_pa,
+				sizeof(struct vmxnet3_adapter), DMA_TO_DEVICE);
+	adapter->adapter_pa = adapter_pa;
+
 	adapter->shared = dma_alloc_coherent(
 				&adapter->pdev->dev,
 				sizeof(struct Vmxnet3_DriverShared),
@@ -3928,6 +3935,9 @@  vmxnet3_probe_device(struct pci_dev *pdev,
 	}
 
 	vmxnet3_check_link(adapter, false);
+	dma_sync_single_for_device(dev, adapter_pa,
+				   sizeof(struct vmxnet3_adapter),
+				   DMA_TO_DEVICE);
 	return 0;
 
 err_register: