From b0d1beeff2a97a0cf1965ea8f1d13b8973f22582 Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Tue, 28 Aug 2018 14:44:25 +0200 Subject: xdp: implement convert_to_xdp_frame for MEM_TYPE_ZERO_COPY MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This commit adds proper MEM_TYPE_ZERO_COPY support for convert_to_xdp_frame. Converting a MEM_TYPE_ZERO_COPY xdp_buff to an xdp_frame is done by transforming the MEM_TYPE_ZERO_COPY buffer into a MEM_TYPE_PAGE_ORDER0 frame. This is costly, and in the future it might make sense to implement a more sophisticated thread-safe alloc/free scheme for MEM_TYPE_ZERO_COPY, so that no allocation and copy is required in the fast-path. Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov --- net/core/xdp.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index 89b6785cef2a..be6cb2f0e722 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -398,3 +398,42 @@ void xdp_attachment_setup(struct xdp_attachment_info *info, info->flags = bpf->flags; } EXPORT_SYMBOL_GPL(xdp_attachment_setup); + +struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) +{ + unsigned int metasize, headroom, totsize; + void *addr, *data_to_copy; + struct xdp_frame *xdpf; + struct page *page; + + /* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */ + metasize = xdp_data_meta_unsupported(xdp) ? 0 : + xdp->data - xdp->data_meta; + headroom = xdp->data - xdp->data_hard_start; + totsize = xdp->data_end - xdp->data + metasize; + + if (sizeof(*xdpf) + totsize > PAGE_SIZE) + return NULL; + + page = dev_alloc_page(); + if (!page) + return NULL; + + addr = page_to_virt(page); + xdpf = addr; + memset(xdpf, 0, sizeof(*xdpf)); + + addr += sizeof(*xdpf); + data_to_copy = metasize ? xdp->data_meta : xdp->data; + memcpy(addr, data_to_copy, totsize); + + xdpf->data = addr + metasize; + xdpf->len = totsize - metasize; + xdpf->headroom = 0; + xdpf->metasize = metasize; + xdpf->mem.type = MEM_TYPE_PAGE_ORDER0; + + xdp_return_buff(xdp); + return xdpf; +} +EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame); -- cgit v1.2.3-59-g8ed1b