arm_vmregion_alloc call
Robert Beckett
bob.beckett at gmail.com
Mon Jul 2 09:57:48 EDT 2012
Hello all,
I just debugged a problem with a USB driver where it was calling
dma_alloc_coherent with a GFP_DMA32 flag.
It turned out that in __dma_alloc_remap, it clears the GFP_DMA and
GFP_HIGHMEM flags when calling arm_vmregion_alloc so that it does not
clash with the slab allocator flag requirements, but it does not clear
GFP_DMA32. The GFP_SLAB_BUG_MASK includes GFP_DMA32, so this looks
like a bug to me. Should it be clearing GFP_DMA32 as well as GFP_DMA
and GFP_HIGHMEM ?
I checked in the latest kernel.org code, and the issue is still there.
Is this a bug, or should it just be calling with GFP_DMA instead of GFP_DMA32?
For now, I am working around it by using GFP_DMA in the
dma_alloc_coherent call as we have no GFP_DMA lower limit, so GFP_DMA
and GFP_DMA32 are the same on my architecture.
Any advice appreciated,
Thanks
Bob
p.s. apologies if this sent multiple times, Im trying to work around
the mailing list "suspicious header" moderation...
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