From: Yonghong Song <yhs@fb.com>
To: <bpf@vger.kernel.org>, Lorenz Bauer <lmb@cloudflare.com>,
Martin KaFai Lau <kafai@fb.com>, <netdev@vger.kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: [PATCH bpf 2/2] selftests/bpf: add bpf_{update,delete}_map_elem in hashmap iter program
Date: Wed, 2 Sep 2020 16:53:41 -0700 [thread overview]
Message-ID: <20200902235341.2001534-1-yhs@fb.com> (raw)
In-Reply-To: <20200902235340.2001300-1-yhs@fb.com>
Added bpf_{updata,delete}_map_elem to the very map element the
iter program is visiting. Due to rcu protection, the visited map
elements, although stale, should still contain correct values.
$ ./test_progs -n 4/18
#4/18 bpf_hash_map:OK
#4 bpf_iter:OK
Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Yonghong Song <yhs@fb.com>
---
.../selftests/bpf/progs/bpf_iter_bpf_hash_map.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
index 07ddbfdbcab7..6dfce3fd68bc 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
@@ -47,7 +47,10 @@ int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx)
__u32 seq_num = ctx->meta->seq_num;
struct bpf_map *map = ctx->map;
struct key_t *key = ctx->key;
+ struct key_t tmp_key;
__u64 *val = ctx->value;
+ __u64 tmp_val = 0;
+ int ret;
if (in_test_mode) {
/* test mode is used by selftests to
@@ -61,6 +64,18 @@ int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx)
if (key == (void *)0 || val == (void *)0)
return 0;
+ /* update the value and then delete the <key, value> pair.
+ * it should not impact the existing 'val' which is still
+ * accessible under rcu.
+ */
+ __builtin_memcpy(&tmp_key, key, sizeof(struct key_t));
+ ret = bpf_map_update_elem(&hashmap1, &tmp_key, &tmp_val, 0);
+ if (ret)
+ return 0;
+ ret = bpf_map_delete_elem(&hashmap1, &tmp_key);
+ if (ret)
+ return 0;
+
key_sum_a += key->a;
key_sum_b += key->b;
key_sum_c += key->c;
--
2.24.1
next prev parent reply other threads:[~2020-09-02 23:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-02 23:53 [PATCH bpf 0/2] bpf: do not use bucket_lock for hashmap iterator Yonghong Song
2020-09-02 23:53 ` [PATCH bpf 1/2] " Yonghong Song
2020-09-03 1:25 ` Andrii Nakryiko
2020-09-03 2:44 ` Yonghong Song
2020-09-04 0:03 ` Alexei Starovoitov
2020-09-02 23:53 ` Yonghong Song [this message]
2020-09-04 0:44 ` [PATCH bpf 0/2] " Alexei Starovoitov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200902235341.2001534-1-yhs@fb.com \
--to=yhs@fb.com \
--cc=ast@fb.com \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kafai@fb.com \
--cc=kernel-team@fb.com \
--cc=lmb@cloudflare.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).