| Message ID | 1412108121-19262-1-git-send-email-seanpaul@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <seanpaul@chromium.org> > --- > 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 <seanpaul@chromium.org> > > --- > > 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.
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().
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); } static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page,
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 <seanpaul@chromium.org> --- arch/arm64/mm/dma-mapping.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)