Comment 0 for bug 1859756

[Bug Description]
 A single transmit packet can span up to 8 descriptors,
 TSO transmit packet can be stored up to 63 descriptors
 and each segment within the TSO should be spanned up to
 8 descriptors.

If the packet needs more than 8 BD, and the total size of
 every 7 continuous frags more than MSS, HW does not support
 it, and it need driver makes SKB Linearized.

[Actual Results]
 iscsi and bigdata spark test OK

[Expected Results]
 iscsi and bigdata spark test OK

[Reproducibility]
 Inevitably

[Additional information]
 Hardware: D06
 Firmware: NA
 Kernel: NA
 DTS2018091810050

[Resolution]
 SW use skb_copy to merge frag;

net: hns3: add 8 BD limit for tx flow
 net: hns3: fix for not calculating tx bd num correctly