在 2022/1/8 下午3:08, Christophe JAILLET 写道:
As stated in [1], dma_set_mask() with a 64-bit mask will never fail if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.
I'd expect to be more verbose here. E.g I see dma_supported() who has a
brunch of checks need to be called if dma_mask is non-NULL.
Thanks
Simplify code and remove some dead code accordingly.
While at it, include directly <linux/dma-mapping.h> instead on relying on
indirect inclusion.
[1]: https://lkml.org/lkml/2021/6/7/398
Signed-off-by: Christophe JAILLET <christophe.jail...@wanadoo.fr>
---
drivers/virtio/virtio_mmio.c | 4 +---
drivers/virtio/virtio_pci_legacy_dev.c | 7 +++----
drivers/virtio/virtio_pci_modern_dev.c | 6 ++----
3 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 56128b9c46eb..aa1efa854de1 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -617,9 +617,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
}
if (rc)
- rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
- if (rc)
- dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying
to continue, but this might not work.\n");
+ dev_warn(&pdev->dev, "Failed to enable DMA. Trying to continue, but
this might not work.\n");
platform_set_drvdata(pdev, vm_dev);
diff --git a/drivers/virtio/virtio_pci_legacy_dev.c b/drivers/virtio/virtio_pci_legacy_dev.c
index 677d1f68bc9b..52b1c4dd43fe 100644
--- a/drivers/virtio/virtio_pci_legacy_dev.c
+++ b/drivers/virtio/virtio_pci_legacy_dev.c
@@ -2,6 +2,7 @@
#include "linux/virtio_pci.h"
#include <linux/virtio_pci_legacy.h>
+#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/pci.h>
@@ -26,9 +27,7 @@ int vp_legacy_probe(struct virtio_pci_legacy_device *ldev)
return -ENODEV;
rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
- if (rc) {
- rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
- } else {
+ if (!rc) {
/*
* The virtio ring base address is expressed as a 32-bit PFN,
* with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
@@ -38,7 +37,7 @@ int vp_legacy_probe(struct virtio_pci_legacy_device *ldev)
}
if (rc)
- dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.
Trying to continue, but this might not work.\n");
+ dev_warn(&pci_dev->dev, "Failed to enable DMA. Trying to continue,
but this might not work.\n");
rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
if (rc)
diff --git a/drivers/virtio/virtio_pci_modern_dev.c
b/drivers/virtio/virtio_pci_modern_dev.c
index e8b3ff2b9fbc..830dc269d68f 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/virtio_pci_modern.h>
+#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/pci.h>
@@ -256,10 +257,7 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
if (err)
- err = dma_set_mask_and_coherent(&pci_dev->dev,
- DMA_BIT_MASK(32));
- if (err)
- dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.
Trying to continue, but this might not work.\n");
+ dev_warn(&pci_dev->dev, "Failed to enable DMA. Trying to continue,
but this might not work.\n");
/* Device capability is only mandatory for devices that have
* device-specific configuration.
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