Hi Sean,
On Tue, Sep 30, 2014 at 09:15:21PM +0100, Sean Paul wrote:
> This patch replaces the static assignment of ~0 to dma_handle with
> DMA_ERROR_CODE to be consistent with other platforms.
>
> In addition to that, it also adds a check for DMA_ERROR_CODE before
> calling __dma_free_coherent with an invalid dma_handle.
>
> Signed-off-by: Sean Paul <[email protected]>
> ---
> arch/arm64/mm/dma-mapping.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 4164c5a..69fd2c4 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -125,7 +125,7 @@ static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
> no_map:
> __dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
> no_mem:
> - *dma_handle = ~0;
> + *dma_handle = DMA_ERROR_CODE;
> return NULL;
> }
>
> @@ -136,7 +136,9 @@ static void __dma_free_noncoherent(struct device *dev, size_t size,
> void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
>
> vunmap(vaddr);
> - __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
> +
> + if (dma_handle != DMA_ERROR_CODE)
> + __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
Is it legal to try and free a DMA buffer after a failed allocation? If so, I
think we need something similar for arch/arm/.
Will
On Wed, Oct 01, 2014 at 11:13:23AM +0100, Will Deacon wrote:
> On Tue, Sep 30, 2014 at 09:15:21PM +0100, Sean Paul wrote:
> > This patch replaces the static assignment of ~0 to dma_handle with
> > DMA_ERROR_CODE to be consistent with other platforms.
> >
> > In addition to that, it also adds a check for DMA_ERROR_CODE before
> > calling __dma_free_coherent with an invalid dma_handle.
> >
> > Signed-off-by: Sean Paul <[email protected]>
> > ---
> > arch/arm64/mm/dma-mapping.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> > index 4164c5a..69fd2c4 100644
> > --- a/arch/arm64/mm/dma-mapping.c
> > +++ b/arch/arm64/mm/dma-mapping.c
> > @@ -125,7 +125,7 @@ static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
> > no_map:
> > __dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
> > no_mem:
> > - *dma_handle = ~0;
> > + *dma_handle = DMA_ERROR_CODE;
> > return NULL;
> > }
> >
> > @@ -136,7 +136,9 @@ static void __dma_free_noncoherent(struct device *dev, size_t size,
> > void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
> >
> > vunmap(vaddr);
> > - __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
> > +
> > + if (dma_handle != DMA_ERROR_CODE)
> > + __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
>
> Is it legal to try and free a DMA buffer after a failed allocation? If so, I
> think we need something similar for arch/arm/.
If the allocation failed, we don't even have a vaddr to unmap, so I
don't see the reason for the additional check.
--
Catalin
On Wed, Oct 01, 2014 at 11:13:23AM +0100, Will Deacon wrote:
> Hi Sean,
>
> On Tue, Sep 30, 2014 at 09:15:21PM +0100, Sean Paul wrote:
> > +
> > + if (dma_handle != DMA_ERROR_CODE)
> > + __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
>
> Is it legal to try and free a DMA buffer after a failed allocation? If so, I
> think we need something similar for arch/arm/.
No.
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)
Free a region of consistent memory you previously allocated. dev,
^^^^^^^^^^^^^^^^^^^^^
This implies that the allocation was successful.
size and dma_handle must all be the same as those passed into
dma_alloc_coherent(). cpu_addr must be the virtual address returned by
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If you want this behaviour, the proper way to do it would be to check
for a NULL cpu_addr, just like kfree() etc.
the dma_alloc_coherent().
--
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.
This patch replaces the static assignment of ~0 to dma_handle with
DMA_ERROR_CODE to be consistent with other platforms.
Signed-off-by: Sean Paul <[email protected]>
---
Changes in v2:
- Removed the check for DMA_ERROR_CODE in __dma_free_noncoherent
the function shouldn't be called after failed allocation
arch/arm64/mm/dma-mapping.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4164c5a..5687dd4 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -125,7 +125,7 @@ static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
no_map:
__dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
no_mem:
- *dma_handle = ~0;
+ *dma_handle = DMA_ERROR_CODE;
return NULL;
}
--
2.1.1
On Wed, Oct 01, 2014 at 04:31:50PM +0100, Sean Paul wrote:
> This patch replaces the static assignment of ~0 to dma_handle with
> DMA_ERROR_CODE to be consistent with other platforms.
>
> Signed-off-by: Sean Paul <[email protected]>
Applied. Thanks.
--
Catalin