2022-01-09 12:51:51

by Christophe JAILLET

Subject: [PATCH] thunderbolt: Remove useless DMA-32 fallback configuration

As stated in [1], dma_set_mask() with a 64-bit mask never fails if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

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 <[email protected]>
---
drivers/thunderbolt/nhi.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index c73da0532be4..4a582183f675 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/pci.h>
+#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/delay.h>
@@ -1229,8 +1230,6 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
spin_lock_init(&nhi->lock);

res = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
- if (res)
- res = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
if (res) {
dev_err(&pdev->dev, "failed to set DMA mask\n");
return res;
--
2.32.0

2022-01-24 19:24:20

by Mika Westerberg

Subject: Re: [PATCH] thunderbolt: Remove useless DMA-32 fallback configuration

On Sun, Jan 09, 2022 at 01:51:31PM +0100, Christophe JAILLET wrote:
> As stated in [1], dma_set_mask() with a 64-bit mask never fails if
> dev->dma_mask is non-NULL.
> So, if it fails, the 32 bits case will also fail for the same reason.
>
> 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 <[email protected]>

Applied, thanks!