4.20-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit b0ca5ecb8e2279d706261f525f1bd0ba9e3fe800 ]
When updating a percpu map, bpftool currently copies the provided value only into the first per CPU copy of the specified value, all others instances are left zeroed.
This change explicitly copies the user-provided bytes to all the per CPU instances, keeping the sub-command syntax unchanged.
v2 -> v3: - drop unused argument, as per Quentin's suggestion v1 -> v2: - rename the helper as per Quentin's suggestion
Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool") Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Quentin Monnet quentin.monnet@netronome.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- tools/bpf/bpftool/map.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 9988d5c126b6..94094168c4a6 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -439,6 +439,20 @@ static char **parse_bytes(char **argv, const char *name, unsigned char *val, return argv + i; }
+/* on per cpu maps we must copy the provided value on all value instances */ +static void fill_per_cpu_value(struct bpf_map_info *info, void *value) +{ + unsigned int i, n, step; + + if (!map_is_per_cpu(info->type)) + return; + + n = get_possible_cpus(); + step = round_up(info->value_size, 8); + for (i = 1; i < n; i++) + memcpy(value + i * step, value, info->value_size); +} + static int parse_elem(char **argv, struct bpf_map_info *info, void *key, void *value, __u32 key_size, __u32 value_size, __u32 *flags, __u32 **value_fd) @@ -518,6 +532,8 @@ static int parse_elem(char **argv, struct bpf_map_info *info, argv = parse_bytes(argv, "value", value, value_size); if (!argv) return -1; + + fill_per_cpu_value(info, value); }
return parse_elem(argv, info, key, NULL, key_size, value_size,