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

[Donggeun Yoo <donggeunyoo.kernel@gmail.com>]

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.