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SubjectRe: [BK-2.5] Update the generic DMA API to take GFP_ flags on
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davem@redhat.com said:
> Now what about the corollary, a platform that needs to sleep to setup
> the cpu mapings in a race-free manner?

This one is the big bug bear. The DMA-mapping.txt doc says
pci_alloc_consistent "may be called in interrupt context". Thus if the
dma_alloc with GFP_ATOMIC uses the same code path, it should be safe.
However, there are indications that pci_alloc_consistent wasn't interrupt safe
on certain platforms (see other email re PA-RISC).

In any event, we're no worse off than we were with the pci_ API. Passing in
the flags will hopefully allow us to create GFP_ATOMIC safe paths in the arch
implementations which look iffy.

James


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