From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn.topel@intel.com>
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
Patch-mainline: v4.20-rc1
Git-commit: b0d1beeff2a97a0cf1965ea8f1d13b8973f22582
References: bsc#1109837
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 <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/net/xdp.h | 5 +++--
net/core/xdp.c | 39 +++++++++++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+), 2 deletions(-)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -91,6 +91,8 @@ static inline void xdp_scrub_frame(struc
frame->dev_rx = NULL;
}
+struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
+
/* Convert xdp_buff to xdp_frame */
static inline
struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
@@ -99,9 +101,8 @@ struct xdp_frame *convert_to_xdp_frame(s
int metasize;
int headroom;
- /* TODO: implement clone, copy, use "native" MEM_TYPE */
if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY)
- return NULL;
+ return xdp_convert_zc_to_xdp_frame(xdp);
/* Assure headroom is available for storing info */
headroom = xdp->data - xdp->data_hard_start;
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -398,3 +398,42 @@ void xdp_attachment_setup(struct xdp_att
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);