* RE: skb_to_sgvec() causes sg_pcopy_to_buffer() wrong
@ 2019-06-21 7:37 Hayes Wang
0 siblings, 0 replies; only message in thread
From: Hayes Wang @ 2019-06-21 7:37 UTC (permalink / raw)
To: netdev; +Cc: linux-kernel, nic_swsd
> 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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