Messages in this thread | | | Subject | Re: "vmalloc", friends and GFP flags | Date | Wed, 01 Jan 2003 16:57:51 -0600 | From | James Bottomley <> |
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> I've just been looking over the state of the ARM {dma,pci}_alloc_consis > tent wrt interrupts etc in 2.5.53, and decided to have a look around > this area for other users. I stumbled across the following unsafe > areas.
> a) parisc. Looking at pa11_dma_alloc_consistent:
I agree with the flow analysis. However, there is a condition attached to getting from pte_alloc_kernel to pte_alloc_one_kernel which makes the GFP_KERNEL allocation. That condition looks to be that the pmd is not present. I don't believe that's possible for an area of memory we just got from __get_free_pages (otherwise the kernel could fault when accessing that region which isn't allowed).
If the above analysis is correct (which I'll defer to better opinion) then we can in practice never get down the problem path, and dma_ allocation from interrupt is safe on parisc.
James
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