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SubjectRe: [PATCH 07/10] x86: add checks for alloc/free_coherent code
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On Fri, 21 Nov 2008 17:26:07 +0100
Joerg Roedel <joerg.roedel@amd.com> wrote:

> Impact: detect bugs in alloc/free_coherent usage
>
> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> ---
> arch/x86/include/asm/dma-mapping.h | 10 +++++-
> arch/x86/include/asm/dma_debug.h | 20 +++++++++++++
> arch/x86/kernel/pci-dma-debug.c | 56 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 84 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> index c7bdb75..2893adb 100644
> --- a/arch/x86/include/asm/dma-mapping.h
> +++ b/arch/x86/include/asm/dma-mapping.h
> @@ -304,8 +304,12 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
> if (!ops->alloc_coherent)
> return NULL;
>
> - return ops->alloc_coherent(dev, size, dma_handle,
> - dma_alloc_coherent_gfp_flags(dev, gfp));
> + memory = ops->alloc_coherent(dev, size, dma_handle,
> + dma_alloc_coherent_gfp_flags(dev, gfp));
> +
> + debug_alloc_coherent(dev, size, *dma_handle, memory);
> +
> + return memory;
> }
>
> static inline void dma_free_coherent(struct device *dev, size_t size,
> @@ -320,6 +324,8 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
>
> if (ops->free_coherent)
> ops->free_coherent(dev, size, vaddr, bus);
> +
> + debug_free_coherent(dev, size, vaddr, bus);
> }
>
> #endif
> diff --git a/arch/x86/include/asm/dma_debug.h b/arch/x86/include/asm/dma_debug.h
> index ff06d1c..7245e27 100644
> --- a/arch/x86/include/asm/dma_debug.h
> +++ b/arch/x86/include/asm/dma_debug.h
> @@ -59,6 +59,14 @@ extern
> void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
> int nelems, int dir);
>
> +extern
> +void debug_alloc_coherent(struct device *dev, size_t size,
> + dma_addr_t dma_addr, void *virt);
> +
> +extern
> +void debug_free_coherent(struct device *dev, size_t size,
> + void *virt, dma_addr_t addr);
> +
> #else /* CONFIG_DMA_API_DEBUG */
>
> static inline
> @@ -90,6 +98,18 @@ void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
> {
> }
>
> +static inline
> +void debug_alloc_coherent(struct device *dev, size_t size,
> + dma_addr_t dma_addr, void *virt)
> +{
> +}
> +
> +static inline
> +void debug_free_coherent(struct device *dev, size_t size,
> + void *virt, dma_addr_t addr)
> +{
> +}
> +
> #endif /* CONFIG_DMA_API_DEBUG */
>
> #endif /* __ASM_X86_DMA_DEBUG */
> diff --git a/arch/x86/kernel/pci-dma-debug.c b/arch/x86/kernel/pci-dma-debug.c
> index 55ef69a..db5ef9a 100644
> --- a/arch/x86/kernel/pci-dma-debug.c
> +++ b/arch/x86/kernel/pci-dma-debug.c
> @@ -352,3 +352,59 @@ void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
> }
> EXPORT_SYMBOL(debug_unmap_sg);
>
> +void debug_alloc_coherent(struct device *dev, size_t size,
> + dma_addr_t dma_addr, void *virt)
> +{
> + unsigned long flags;
> + struct dma_debug_entry *entry;
> +
> + if (dma_addr == bad_dma_address)
> + return;
> +
> + entry = dma_entry_alloc();
> + if (!entry)
> + return;
> +
> + entry->type = DMA_DEBUG_COHERENT;
> + entry->dev = dev;
> + entry->cpu_addr = virt;
> + entry->size = size;
> + entry->dev_addr = dma_addr;
> + entry->direction = DMA_BIDIRECTIONAL;
> +
> + spin_lock_irqsave(&dma_lock, flags);
> + add_dma_entry(entry);
> + spin_unlock_irqrestore(&dma_lock, flags);
> +}
> +EXPORT_SYMBOL(debug_alloc_coherent);

Can you clean up the duplication in debug_map_single, debug_map_sg,
and debug_alloc_coherent? The higher-level helper functions might
help.


> +void debug_free_coherent(struct device *dev, size_t size,
> + void *virt, dma_addr_t addr)
> +{
> + unsigned long flags;
> + struct dma_debug_entry ref = {
> + .type = DMA_DEBUG_COHERENT,
> + .dev = dev,
> + .cpu_addr = virt,
> + .dev_addr = addr,
> + .size = size,
> + .direction = DMA_BIDIRECTIONAL,
> + };
> + struct dma_debug_entry *entry;
> +
> + if (addr == bad_dma_address)
> + return;
> +
> + spin_lock_irqsave(&dma_lock, flags);
> +
> + entry = find_dma_entry(&ref);
> +
> + if (check_unmap(&ref, entry)) {
> + remove_dma_entry(entry);
> + dma_entry_free(entry);
> + }
> +
> + spin_unlock_irqrestore(&dma_lock, flags);
> +}
> +EXPORT_SYMBOL(debug_free_coherent);

Ditto.


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