[dm-devel] [PATCH 1/4] scatterlist: Introduce some helper functions

[Baolin Wang]

>>> + **/
>>> +static inline bool sg_is_contiguous(struct scatterlist *sga,
>>> +                                 struct scatterlist *sgb)
>>> +{
>>> +     return ((sga->page_link & ~0x3UL) + sga->offset + sga->length ==
>>> +             (sgb->page_link & ~0x3UL));
>>> +}
>> I don't understand that one.
>> sga->page_link is a pointer to a "struct page *". How can it be added to an
>> offset within a page ???
>
>
> Ah, sorry that's a mistake. It should check as below:
> static inline bool sg_is_contiguous(struct scatterlist *sga, struct
> scatterlist *sgb)
> {
>     return (unsigned int)sg_virt(sga) + sga->length == (unsigned
> int)sg_virt(sgb);
> }

sorry, it should be:
static inline bool sg_is_contiguous(struct scatterlist *sga,
   struct scatterlist *sgb)
{
    return (unsigned long)sg_virt(sga) + sga->length ==
               (unsigned long)sg_virt(sgb);
}

-- 
Baolin.wang
Best Regards