> On Thu, Sep 03, 2020 at 10:58:51PM +0200, Lorenzo Bianconi wrote: > > From: Sameeh Jubran <sameehj@xxxxxxxxxx> > > > > The implementation is based on this [0] draft by Jesper D. Brouer. > > > > Provided two new helpers: > > > > * bpf_xdp_get_frag_count() > > * bpf_xdp_get_frags_total_size() > > > > [0] xdp mb design - https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > > Signed-off-by: Sameeh Jubran <sameehj@xxxxxxxxxx> > > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> > > --- > > include/uapi/linux/bpf.h | 14 ++++++++++++ > > net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++ > > tools/include/uapi/linux/bpf.h | 14 ++++++++++++ > > 3 files changed, 67 insertions(+) > > > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > > index c4a6d245619c..53db75095306 100644 > > --- a/include/uapi/linux/bpf.h > > +++ b/include/uapi/linux/bpf.h > > @@ -3590,6 +3590,18 @@ union bpf_attr { > > * > > * Return > > * 0 on success, or a negative error in case of failure. [...] > > + > > I only quickly jumped through series and IMHO this helper should be > rewritten/optimized in a way that we bail out as early as possible if > !xdp->mb as the rest of the code on that condition will do nothing and i'm > not sure if compiler would optimize it. > > > struct skb_shared_info *sinfo; > int nfrags, i; > int size = 0; > > if (!xdp->mb) > return 0; > > sinfo = xdp_get_shared_info_from_buff(xdp); > > nfrags = min(sinfo->nr_frags, MAX_SKB_FRAGS); > > for (i = 0; i < nfrags; i++) > size += skb_frag_size(&sinfo->frags[i]); > > return size; > > Thoughts? I agree. Regards, Lorenzo > > > > + return size; > > +} > > + > > +const struct bpf_func_proto bpf_xdp_get_frags_total_size_proto = { > > + .func = bpf_xdp_get_frags_total_size, > > + .gpl_only = false, > > + .ret_type = RET_INTEGER, > > + .arg1_type = ARG_PTR_TO_CTX, > > +}; > > + > > BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) > > { > > void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */ > > @@ -6889,6 +6924,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > > return &bpf_xdp_adjust_tail_proto; > > case BPF_FUNC_xdp_adjust_mb_header: > > return &bpf_xdp_adjust_mb_header_proto; > > + case BPF_FUNC_xdp_get_frag_count: > > + return &bpf_xdp_get_frag_count_proto; > > + case BPF_FUNC_xdp_get_frags_total_size: > > + return &bpf_xdp_get_frags_total_size_proto; > > case BPF_FUNC_fib_lookup: > > return &bpf_xdp_fib_lookup_proto; > > #ifdef CONFIG_INET > > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h > > index 392d52a2ecef..dd4669096cbb 100644 > > --- a/tools/include/uapi/linux/bpf.h > > +++ b/tools/include/uapi/linux/bpf.h > > @@ -3591,6 +3591,18 @@ union bpf_attr { > > * > > * Return > > * 0 on success, or a negative error in case of failure. > > + * > > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md) > > + * Description > > + * Get the total number of frags for a given packet. > > + * Return > > + * The number of frags > > + * > > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md) > > + * Description > > + * Get the total size of frags for a given packet. > > + * Return > > + * The total size of frags for a given packet. > > */ > > #define __BPF_FUNC_MAPPER(FN) \ > > FN(unspec), \ > > @@ -3743,6 +3755,8 @@ union bpf_attr { > > FN(d_path), \ > > FN(copy_from_user), \ > > FN(xdp_adjust_mb_header), \ > > + FN(xdp_get_frag_count), \ > > + FN(xdp_get_frags_total_size), \ > > /* */ > > > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > > -- > > 2.26.2 > >
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