On Sat, Sep 27, 2014 at 11:13 PM, Catalin Marinas <catalin.mari...@arm.com> wrote: > On 27 Sep 2014, at 16:09, Miles MH Chen <orca.c...@gmail.com> wrote: >> Signed-off-by: Min-Hua Chen <orca.c...@gmail.com> >> --- >> arch/arm64/mm/dma-mapping.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c >> index 4164c5a..273cf6d 100644 >> --- a/arch/arm64/mm/dma-mapping.c >> +++ b/arch/arm64/mm/dma-mapping.c >> @@ -103,7 +103,8 @@ static void *__dma_alloc_noncoherent(struct device *dev, >> size_t size, >> ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs); >> if (!ptr) >> goto no_mem; >> - map = kmalloc(sizeof(struct page *) << order, flags & ~GFP_DMA); >> + map = kmalloc(sizeof(struct page *) << order, >> + flags & ~(GFP_DMA | GFP_DMA32)); > > Do you have an explanation on why this is needed (and such explanation > should also be included in the commit log)? We don’t use ZONE_DMA32 on > arm64 (we did initially but it was for the wrong reasons).
If GFP_DMA32 is passed to dma_alloc_coherent, the flag will go to kmalloc and trigger a BUG_ON check in slab allocator: __dma_alloc_noncoherent kmalloc new_slab BUG_ON(flags & GFP_SLAB_BUG_MASK); It can be avoided this by removing GFP_DMA32 before passing it to kmalloc or we should block GFP_DMA32 flag earlier in arch/arm64/dma-mapping.c if GFP_DMA32 is not allowed in arch/arm64/dma-mapping.c. Thanks, MH > > Thanks, > > Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
