On 2/12/19 10:19 AM, Jesper Dangaard Brouer wrote:
> On Tue, 12 Feb 2019 10:05:39 -0800
> Florian Fainelli <f.faine...@gmail.com> wrote:
>
>> On 2/12/19 6:49 AM, Jesper Dangaard Brouer wrote:
>>> The page_pool API is using page->private to store DMA addresses.
>>> As pointed out by David Miller we can't use that on 32-bit architectures
>>> with 64-bit DMA
>>>
>>> This patch adds a new dma_addr_t struct to allow storing DMA addresses
>>>
>>> Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
>>> Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
>>> Acked-by: Andrew Morton <a...@linux-foundation.org>
>>> ---
>>> include/linux/mm_types.h | 7 +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
>>> index 2c471a2c43fa..581737bd0878 100644
>>> --- a/include/linux/mm_types.h
>>> +++ b/include/linux/mm_types.h
>>> @@ -95,6 +95,13 @@ struct page {
>>> */
>>> unsigned long private;
>>> };
>>> + struct { /* page_pool used by netstack */
>>> + /**
>>> + * @dma_addr: page_pool requires a 64-bit value even on
>>> + * 32-bit architectures.
>>> + */
>>
>> Nit: might require? dma_addr_t, as you mention in the commit may have a
>> different size based on CONFIG_ARCH_DMA_ADDR_T_64BIT.
>
> So you want me to change the comment to be:
>
> /**
> * @dma_addr: might require a 64-bit value even on
> * 32-bit architectures.
> */
>
> Correctly understood?
Correct, that is what I would change. The commit message is correct, but
the comment makes it sound like dma_addr_t is guaranteed to be 64-bit,
while it is actually platform dependent. Does that make it clearer?
--
Florian
