2017-06-13 20:56:31

by Olav Haugan

Subject: [PATCH v2] arm64/dma-mapping: Remove extraneous null-pointer checks

The current null-pointer check in __dma_alloc_coherent and
__dma_free_coherent is not needed anymore since the
__dma_alloc/__dma_free functions won't be called if !dev (dummy ops will
be called instead).

Signed-off-by: Olav Haugan <[email protected]>
---
arch/arm64/include/asm/dma-mapping.h | 2 --
arch/arm64/mm/dma-mapping.c | 9 ---------
2 files changed, 11 deletions(-)

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index 5392dbeffa45..f72779aad276 100644
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -48,8 +48,6 @@ void arch_teardown_dma_ops(struct device *dev);
/* do not use this function in a driver */
static inline bool is_device_dma_coherent(struct device *dev)
{
- if (!dev)
- return false;
return dev->archdata.dma_coherent;
}

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 3216e098c058..3e340b625436 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -95,11 +95,6 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flags,
unsigned long attrs)
{
- if (dev == NULL) {
- WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
- return NULL;
- }
-
if (IS_ENABLED(CONFIG_ZONE_DMA) &&
dev->coherent_dma_mask <= DMA_BIT_MASK(32))
flags |= GFP_DMA;
@@ -128,10 +123,6 @@ static void __dma_free_coherent(struct device *dev, size_t size,
bool freed;
phys_addr_t paddr = dma_to_phys(dev, dma_handle);

- if (dev == NULL) {
- WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
- return;
- }

freed = dma_release_from_contiguous(dev,
phys_to_page(paddr),
--
2.13.0

2017-06-14 12:34:29

by Catalin Marinas

Subject: Re: [PATCH v2] arm64/dma-mapping: Remove extraneous null-pointer checks

On Tue, Jun 13, 2017 at 01:56:14PM -0700, Olav Haugan wrote:
> The current null-pointer check in __dma_alloc_coherent and
> __dma_free_coherent is not needed anymore since the
> __dma_alloc/__dma_free functions won't be called if !dev (dummy ops will
> be called instead).
>
> Signed-off-by: Olav Haugan <[email protected]>
> ---
> arch/arm64/include/asm/dma-mapping.h | 2 --
> arch/arm64/mm/dma-mapping.c | 9 ---------
> 2 files changed, 11 deletions(-)

Thanks.

Reviewed-by: Catalin Marinas <[email protected]>

Will should pick this up for 4.13

--
Catalin