> Use skb_to_sgvec() to set scatter list, and sometime we would get a
> sg->offset which is more than PAGE_SIZE. Call sg_pcopy_to_buffer()
> with this scatter list would get wrong data.
> 
> In sg_miter_get_next_page(), you would get wrong miter->__remaining,
> when the sg->offset is more than PAGE_SIZE.
> 
> static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)
> {
>       if (!miter->__remaining) {
>               struct scatterlist *sg;
>               unsigned long pgoffset;
> 
>               if (!__sg_page_iter_next(&miter->piter))
>                       return false;
> 
>               sg = miter->piter.sg;
>               pgoffset = miter->piter.sg_pgoffset;
> 
>               miter->__offset = pgoffset ? 0 : sg->offset;
>               miter->__remaining = sg->offset + sg->length -
>                               (pgoffset << PAGE_SHIFT) - miter->__offset;
>               miter->__remaining = min_t(unsigned long, miter->__remaining,
>                                          PAGE_SIZE - miter->__offset);
>       }
> 
>       return true;
> }

Excuse me. The following patch could solve my problem.

https://patchwork.kernel.org/patch/11000549/

Best Regards,
Hayes

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