Re: [PATCH] dma-mapping: don't trace the DMA address when the allocation fails

[Sean Anderson]

On 9/5/26 13:26, Donggeun Yoo wrote:
> On 9/5/26 08:57, Sean Anderson wrote:
> > I don't understand what you mean. We are literally in an if-statement
> > that checks whether the allocation succeeded.
>
> That if checks whether the device has a coherent pool, not whether the
> allocation out of it worked. dma_alloc_from_dev_coherent():
>
>   * Returns 0 if dma_alloc_coherent should continue with allocating from
>   * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
>
> It returns 1 as soon as it finds a pool; __dma_alloc_from_coherent()
> stores NULL in @ret and leaves *dma_handle alone when the request is
> larger than the pool or the pool is full. The third paragraph of the
> commit message says this.
>
> The second hunk is under no condition at all: dma_direct_alloc(),
> iommu_dma_alloc() and ops->alloc() return NULL on failure, and the trace
> below the if/else chain runs either way.

Ah, I see what you mean. TBH I would just do something like

cpu_handle ? *dma_handle : NULL

to make it clear what we're doing

--Sean