Messages in this thread | | | Subject | Re: [PATCH] dma-direct: Fix return value of dma_direct_supported | From | Robin Murphy <> | Date | Thu, 4 Oct 2018 12:25:47 +0100 |
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On 04/10/18 00:48, Alexander Duyck wrote: > It appears that in commit 9d7a224b463e ("dma-direct: always allow dma mask > <= physiscal memory size") the logic of the test was changed from a "<" to > a ">=" however I don't see any reason for that change. I am assuming that > there was some additional change planned, specifically I suspect the logic > was intended to be reversed and possibly used for a return. Since that is > the case I have gone ahead and done that.
Bah, seems I got hung up on the min_mask code above it and totally overlooked that the condition itself got flipped. It probably also can't help that it's an int return type, but treated as a bool by callers rather than "0 for success" as int tends to imply in isolation.
Anyway, paying a bit more attention this time, I think this looks like the right fix - cheers Alex.
Robin.
> This addresses issues I had on my system that prevented me from booting > with the above mentioned commit applied on an x86_64 system w/ Intel IOMMU. > > Fixes: 9d7a224b463e ("dma-direct: always allow dma mask <= physiscal memory size") > Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> > --- > kernel/dma/direct.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index 5a0806b5351b..65872f6c2e93 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -301,9 +301,7 @@ int dma_direct_supported(struct device *dev, u64 mask) > > min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT); > > - if (mask >= phys_to_dma(dev, min_mask)) > - return 0; > - return 1; > + return mask >= phys_to_dma(dev, min_mask); > } > > int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr) > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu >
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