When performing IPv6 forwarding, there is an expectation that SKBs will have some headroom. When forwarding a packet from the aquantia driver, this does not always happen, triggering a kernel warning. aq_ring.c has this code (edited slightly for brevity): if (buff->is_eop && buff->len <= AQ_CFG_RX_FRAME_MAX - AQ_SKB_ALIGN) { skb = build_skb(aq_buf_vaddr(&buff->rxdata), AQ_CFG_RX_FRAME_MAX); } else { skb = napi_alloc_skb(napi, AQ_CFG_RX_HDR_SIZE); There is a significant difference between the SKB produced by these 2 code paths. When napi_alloc_skb creates an SKB, there is a certain amount of headroom reserved. However, this is not done in the build_skb codepath. As the hardware buffer that build_skb is built around does not handle the presence of the SKB header, this code path is being removed and the napi_alloc_skb path will always be used. This code path does have to copy the packet header into the SKB, but it adds the packet data as a frag. Fixes: 018423e90bee ("net: ethernet: aquantia: Add ring support code") Signed-off-by: Lincoln Ramsay <lincoln.ramsay@opengear.com> Link: https://lore.kernel.org/r/MWHPR1001MB23184F3EAFA413E0D1910EC9E8FC0@MWHPR1001MB2318.namprd10.prod.outlook.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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