On Sat, Nov 23, 2019 at 08:12:21AM +0100, Björn Töpel wrote:
> From: Björn Töpel <bjorn.topel@xxxxxxxxx>
>
> The xdp_call.h header wraps a more user-friendly API around the BPF
> dispatcher. A user adds a trampoline/XDP caller using the
> DEFINE_XDP_CALL macro, and updates the BPF dispatcher via
> xdp_call_update(). The actual dispatch is done via xdp_call().
>
> Note that xdp_call() is only supported for builtin drivers. Module
> builds will fallback to bpf_prog_run_xdp().
>
> The next patch will show-case how the i40e driver uses xdp_call.
>
> Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
> ---
> include/linux/xdp_call.h | 66 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 66 insertions(+)
> create mode 100644 include/linux/xdp_call.h
>
> diff --git a/include/linux/xdp_call.h b/include/linux/xdp_call.h
> new file mode 100644
> index 000000000000..69b2d325a787
> --- /dev/null
> +++ b/include/linux/xdp_call.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/* Copyright(c) 2019 Intel Corporation. */
> +#ifndef _LINUX_XDP_CALL_H
> +#define _LINUX_XDP_CALL_H
> +
> +#include <linux/filter.h>
> +
> +#if defined(CONFIG_BPF_JIT) && defined(CONFIG_RETPOLINE) && !defined(MODULE)
> +
> +void bpf_dispatcher_change_prog(void *func, struct bpf_prog *from,
> + struct bpf_prog *to);
> +
> +#define XDP_CALL_TRAMP(name) ____xdp_call_##name##_tramp
> +
> +#define DEFINE_XDP_CALL(name) \
> + unsigned int XDP_CALL_TRAMP(name)( \
> + const void *xdp_ctx, \
> + const struct bpf_insn *insnsi, \
> + unsigned int (*bpf_func)(const void *, \
> + const struct bpf_insn *)) \
> + { \
> + return bpf_func(xdp_ctx, insnsi); \
> + }
> +
> +#define DECLARE_XDP_CALL(name) \
> + unsigned int XDP_CALL_TRAMP(name)( \
> + const void *xdp_ctx, \
> + const struct bpf_insn *insnsi, \
> + unsigned int (*bpf_func)(const void *, \
> + const struct bpf_insn *))
> +
> +#define xdp_call_run(name, prog, ctx) ({ \
> + u32 ret; \
> + cant_sleep(); \
> + if (static_branch_unlikely(&bpf_stats_enabled_key)) { \
> + struct bpf_prog_stats *stats; \
> + u64 start = sched_clock(); \
> + ret = XDP_CALL_TRAMP(name)(ctx, \
> + (prog)->insnsi, \
> + (prog)->bpf_func); \
> + stats = this_cpu_ptr((prog)->aux->stats); \
> + u64_stats_update_begin(&stats->syncp); \
> + stats->cnt++; \
> + stats->nsecs += sched_clock() - start; \
> + u64_stats_update_end(&stats->syncp); \
> + } else { \
> + ret = XDP_CALL_TRAMP(name)(ctx, \
> + (prog)->insnsi, \
> + (prog)->bpf_func); \
> + } \
> + ret; })
I cannot help but wonder whether it's possible to avoid copy-paste from
BPF_PROG_RUN().
At least could you place this new macro right next to BPF_PROG_RUN?
If it's in a different file eventually they may diverge.
