diff options
author | Jesper Dangaard Brouer <brouer@redhat.com> | 2018-01-03 13:25:13 +0300 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2018-01-06 02:21:20 +0300 |
commit | aecd67b60722dd24353b0bc50e78a55b30707dcd (patch) | |
tree | d9c107a5ab64864470ab7d2173340cc428cd562c /net/core/xdp.c | |
parent | 5f103c5d4dbadec0f2cacd39b6429e1b8a8cf983 (diff) |
xdp: base API for new XDP rx-queue info concept
This patch only introduce the core data structures and API functions.
All XDP enabled drivers must use the API before this info can used.
There is a need for XDP to know more about the RX-queue a given XDP
frames have arrived on. For both the XDP bpf-prog and kernel side.
Instead of extending xdp_buff each time new info is needed, the patch
creates a separate read-mostly struct xdp_rxq_info, that contains this
info. We stress this data/cache-line is for read-only info. This is
NOT for dynamic per packet info, use the data_meta for such use-cases.
The performance advantage is this info can be setup at RX-ring init
time, instead of updating N-members in xdp_buff. A possible (driver
level) micro optimization is that xdp_buff->rxq assignment could be
done once per XDP/NAPI loop. The extra pointer deref only happens for
program needing access to this info (thus, no slowdown to existing
use-cases).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/core/xdp.c')
-rw-r--r-- | net/core/xdp.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c new file mode 100644 index 000000000000..229bc5a0ee04 --- /dev/null +++ b/net/core/xdp.c @@ -0,0 +1,67 @@ +/* net/core/xdp.c + * + * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. + * Released under terms in GPL version 2. See COPYING. + */ +#include <linux/types.h> +#include <linux/mm.h> + +#include <net/xdp.h> + +#define REG_STATE_NEW 0x0 +#define REG_STATE_REGISTERED 0x1 +#define REG_STATE_UNREGISTERED 0x2 +#define REG_STATE_UNUSED 0x3 + +void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq) +{ + /* Simplify driver cleanup code paths, allow unreg "unused" */ + if (xdp_rxq->reg_state == REG_STATE_UNUSED) + return; + + WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG"); + + xdp_rxq->reg_state = REG_STATE_UNREGISTERED; + xdp_rxq->dev = NULL; +} +EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg); + +static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq) +{ + memset(xdp_rxq, 0, sizeof(*xdp_rxq)); +} + +/* Returns 0 on success, negative on failure */ +int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, + struct net_device *dev, u32 queue_index) +{ + if (xdp_rxq->reg_state == REG_STATE_UNUSED) { + WARN(1, "Driver promised not to register this"); + return -EINVAL; + } + + if (xdp_rxq->reg_state == REG_STATE_REGISTERED) { + WARN(1, "Missing unregister, handled but fix driver"); + xdp_rxq_info_unreg(xdp_rxq); + } + + if (!dev) { + WARN(1, "Missing net_device from driver"); + return -ENODEV; + } + + /* State either UNREGISTERED or NEW */ + xdp_rxq_info_init(xdp_rxq); + xdp_rxq->dev = dev; + xdp_rxq->queue_index = queue_index; + + xdp_rxq->reg_state = REG_STATE_REGISTERED; + return 0; +} +EXPORT_SYMBOL_GPL(xdp_rxq_info_reg); + +void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq) +{ + xdp_rxq->reg_state = REG_STATE_UNUSED; +} +EXPORT_SYMBOL_GPL(xdp_rxq_info_unused); |