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Message-ID: <CAEKGpzgz4U68ast=OSMFq66OKNipMB_BN9E2_N4PEO_+s+LByQ@mail.gmail.com>
Date: Thu, 7 Nov 2019 09:44:09 +0900
From: "Daniel T. Lee" <danieltimlee@...il.com>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>,
Alexei Starovoitov <ast@...nel.org>,
Andrii Nakryiko <andriin@...com>,
Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>
Subject: Re: [PATCH,bpf-next 2/2] samples: bpf: update map definition to new
syntax BTF-defined map
On Wed, Nov 6, 2019 at 11:14 AM Andrii Nakryiko
<andrii.nakryiko@...il.com> wrote:
>
> On Tue, Nov 5, 2019 at 2:52 PM Daniel T. Lee <danieltimlee@...il.com> wrote:
> >
> > Since, the new syntax of BTF-defined map has been introduced,
> > the syntax for using maps under samples directory are mixed up.
> > For example, some are already using the new syntax, and some are using
> > existing syntax by calling them as 'legacy'.
> >
> > As stated at commit abd29c931459 ("libbpf: allow specifying map
> > definitions using BTF"), the BTF-defined map has more compatablility
> > with extending supported map definition features.
> >
> > The commit doesn't replace all of the map to new BTF-defined map,
> > because some of the samples still use bpf_load instead of libbpf, which
> > can't properly create BTF-defined map.
> >
> > This will only updates the samples which uses libbpf API for loading bpf
> > program. (ex. bpf_prog_load_xattr)
> >
> > Signed-off-by: Daniel T. Lee <danieltimlee@...il.com>
> > ---
>
>
> Please try to stick to __type() for key/value, where possible (all the
> arrays, hashes, per-cpu arrays definitely work). Some of the special
> CPUMAP, DEVMAP might not work. Not sure about TRIEs, please try.
>
Will apply feedback right away!
Thanks for the review!
> > samples/bpf/sockex1_kern.c | 12 ++--
> > samples/bpf/sockex2_kern.c | 12 ++--
> > samples/bpf/xdp1_kern.c | 12 ++--
> > samples/bpf/xdp2_kern.c | 12 ++--
> > samples/bpf/xdp_adjust_tail_kern.c | 12 ++--
> > samples/bpf/xdp_fwd_kern.c | 13 ++--
> > samples/bpf/xdp_redirect_cpu_kern.c | 108 ++++++++++++++--------------
> > samples/bpf/xdp_redirect_kern.c | 24 +++----
> > samples/bpf/xdp_redirect_map_kern.c | 24 +++----
> > samples/bpf/xdp_router_ipv4_kern.c | 64 ++++++++---------
> > samples/bpf/xdp_rxq_info_kern.c | 36 +++++-----
> > samples/bpf/xdp_tx_iptunnel_kern.c | 26 +++----
> > 12 files changed, 177 insertions(+), 178 deletions(-)
> >
> > diff --git a/samples/bpf/sockex1_kern.c b/samples/bpf/sockex1_kern.c
> > index f96943f443ab..493f102711c0 100644
> > --- a/samples/bpf/sockex1_kern.c
> > +++ b/samples/bpf/sockex1_kern.c
> > @@ -5,12 +5,12 @@
> > #include "bpf_helpers.h"
> > #include "bpf_legacy.h"
> >
> > -struct bpf_map_def SEC("maps") my_map = {
> > - .type = BPF_MAP_TYPE_ARRAY,
> > - .key_size = sizeof(u32),
> > - .value_size = sizeof(long),
> > - .max_entries = 256,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_ARRAY);
> > + __uint(key_size, sizeof(u32));
> > + __uint(value_size, sizeof(long));
> > + __uint(max_entries, 256);
> > +} my_map SEC(".maps");
> >
> > SEC("socket1")
> > int bpf_prog1(struct __sk_buff *skb)
> > diff --git a/samples/bpf/sockex2_kern.c b/samples/bpf/sockex2_kern.c
> > index 5566fa7d92fa..bd756494625b 100644
> > --- a/samples/bpf/sockex2_kern.c
> > +++ b/samples/bpf/sockex2_kern.c
> > @@ -190,12 +190,12 @@ struct pair {
> > long bytes;
> > };
> >
> > -struct bpf_map_def SEC("maps") hash_map = {
> > - .type = BPF_MAP_TYPE_HASH,
> > - .key_size = sizeof(__be32),
> > - .value_size = sizeof(struct pair),
> > - .max_entries = 1024,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_HASH);
> > + __uint(key_size, sizeof(__be32));
> > + __uint(value_size, sizeof(struct pair));
>
> let's use __type(key, __be32) and __type(value, struct pair) here and
> in most other places where we have maps supporting BTF
>
> > + __uint(max_entries, 1024);
> > +} hash_map SEC(".maps");
> >
> > SEC("socket2")
> > int bpf_prog2(struct __sk_buff *skb)
> > diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
> > index 219742106bfd..a0a181164087 100644
> > --- a/samples/bpf/xdp1_kern.c
> > +++ b/samples/bpf/xdp1_kern.c
> > @@ -14,12 +14,12 @@
> > #include <linux/ipv6.h>
> > #include "bpf_helpers.h"
> >
> > -struct bpf_map_def SEC("maps") rxcnt = {
> > - .type = BPF_MAP_TYPE_PERCPU_ARRAY,
> > - .key_size = sizeof(u32),
> > - .value_size = sizeof(long),
> > - .max_entries = 256,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
> > + __uint(key_size, sizeof(u32));
> > + __uint(value_size, sizeof(long));
> > + __uint(max_entries, 256);
> > +} rxcnt SEC(".maps");
> >
> > static int parse_ipv4(void *data, u64 nh_off, void *data_end)
> > {
> > diff --git a/samples/bpf/xdp2_kern.c b/samples/bpf/xdp2_kern.c
> > index e01288867d15..21564a95561b 100644
> > --- a/samples/bpf/xdp2_kern.c
> > +++ b/samples/bpf/xdp2_kern.c
> > @@ -14,12 +14,12 @@
> > #include <linux/ipv6.h>
> > #include "bpf_helpers.h"
> >
> > -struct bpf_map_def SEC("maps") rxcnt = {
> > - .type = BPF_MAP_TYPE_PERCPU_ARRAY,
> > - .key_size = sizeof(u32),
> > - .value_size = sizeof(long),
> > - .max_entries = 256,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
> > + __uint(key_size, sizeof(u32));
> > + __uint(value_size, sizeof(long));
> > + __uint(max_entries, 256);
> > +} rxcnt SEC(".maps");
> >
> > static void swap_src_dst_mac(void *data)
> > {
> > diff --git a/samples/bpf/xdp_adjust_tail_kern.c b/samples/bpf/xdp_adjust_tail_kern.c
> > index c616508befb9..6de45a4a2c3e 100644
> > --- a/samples/bpf/xdp_adjust_tail_kern.c
> > +++ b/samples/bpf/xdp_adjust_tail_kern.c
> > @@ -28,12 +28,12 @@
> > /* volatile to prevent compiler optimizations */
> > static volatile __u32 max_pcktsz = MAX_PCKT_SIZE;
> >
> > -struct bpf_map_def SEC("maps") icmpcnt = {
> > - .type = BPF_MAP_TYPE_ARRAY,
> > - .key_size = sizeof(__u32),
> > - .value_size = sizeof(__u64),
> > - .max_entries = 1,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_ARRAY);
> > + __uint(key_size, sizeof(__u32));
> > + __uint(value_size, sizeof(__u64));
> > + __uint(max_entries, 1);
> > +} icmpcnt SEC(".maps");
> >
> > static __always_inline void count_icmp(void)
> > {
> > diff --git a/samples/bpf/xdp_fwd_kern.c b/samples/bpf/xdp_fwd_kern.c
> > index 701a30f258b1..d013029aeaa2 100644
> > --- a/samples/bpf/xdp_fwd_kern.c
> > +++ b/samples/bpf/xdp_fwd_kern.c
> > @@ -23,13 +23,12 @@
> >
> > #define IPV6_FLOWINFO_MASK cpu_to_be32(0x0FFFFFFF)
> >
> > -/* For TX-traffic redirect requires net_device ifindex to be in this devmap */
> > -struct bpf_map_def SEC("maps") xdp_tx_ports = {
> > - .type = BPF_MAP_TYPE_DEVMAP,
> > - .key_size = sizeof(int),
> > - .value_size = sizeof(int),
> > - .max_entries = 64,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_DEVMAP);
> > + __uint(key_size, sizeof(int));
> > + __uint(value_size, sizeof(int));
> > + __uint(max_entries, 64);
> > +} xdp_tx_ports SEC(".maps");
>
> DEVMAP might be special, I don't remember, so key_size/value_size
> might be necessary
As you've mentioned, DEVMAP does not work with __type.
>
> >
> > /* from include/net/ip.h */
> > static __always_inline int ip_decrease_ttl(struct iphdr *iph)
> > diff --git a/samples/bpf/xdp_redirect_cpu_kern.c b/samples/bpf/xdp_redirect_cpu_kern.c
> > index a306d1c75622..1f472506aa54 100644
> > --- a/samples/bpf/xdp_redirect_cpu_kern.c
> > +++ b/samples/bpf/xdp_redirect_cpu_kern.c
> > @@ -18,12 +18,12 @@
> > #define MAX_CPUS 64 /* WARNING - sync with _user.c */
> >
> > /* Special map type that can XDP_REDIRECT frames to another CPU */
> > -struct bpf_map_def SEC("maps") cpu_map = {
> > - .type = BPF_MAP_TYPE_CPUMAP,
> > - .key_size = sizeof(u32),
> > - .value_size = sizeof(u32),
> > - .max_entries = MAX_CPUS,
> > -};
> > +struct {
> > + __uint(type, BPF_MAP_TYPE_CPUMAP);
> > + __uint(key_size, sizeof(u32));
> > + __uint(value_size, sizeof(u32));
> > + __uint(max_entries, MAX_CPUS);
> > +} cpu_map SEC(".maps");
> >
>
> same for CPUMAP, but would be nice to double-check.
>
Same for the CPUMAP. Just checked.
Seems TRIE doesn't work either. it uses __uint(key_size, 8);
and __type(key, 8); is not acceptable.
[...]
Thank you for your time and effort for the review.
Thanks,
Daniel
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