ACK: [SRU][Groovy][PATCH 1/1] UBUNTU: SAUCE: partially revert "bpf: Zero-fill re-used per-cpu map element"

[Stefan Bader]

On 04.03.21 18:50, Kleber Sacilotto de Souza wrote:
> BugLink: https://bugs.launchpad.net/bugs/1917609
> 
> Upstream commit d3bec0138bfbe58606fc1d6f57a4cdc1a20218db (bpf: Zero-fill
> re-used per-cpu map element) applied to Groovy via upstream stable
> update adds new bpf selftests which can't be built on the 5.8 kernel due
> to missing helper functions which were added later.
> 
> Partially revert this commit to remove the selftests changes but keeping
> the actual bpf changes made to kernel/bpf/hashtab.c.
> 
> Signed-off-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>   .../selftests/bpf/prog_tests/map_init.c       | 214 ------------------
>   .../selftests/bpf/progs/test_map_init.c       |  33 ---
>   2 files changed, 247 deletions(-)
>   delete mode 100644 tools/testing/selftests/bpf/prog_tests/map_init.c
>   delete mode 100644 tools/testing/selftests/bpf/progs/test_map_init.c
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
> deleted file mode 100644
> index 14a31109dd0e..000000000000
> --- a/tools/testing/selftests/bpf/prog_tests/map_init.c
> +++ /dev/null
> @@ -1,214 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
> -
> -#include <test_progs.h>
> -#include "test_map_init.skel.h"
> -
> -#define TEST_VALUE 0x1234
> -#define FILL_VALUE 0xdeadbeef
> -
> -static int nr_cpus;
> -static int duration;
> -
> -typedef unsigned long long map_key_t;
> -typedef unsigned long long map_value_t;
> -typedef struct {
> -	map_value_t v; /* padding */
> -} __bpf_percpu_val_align pcpu_map_value_t;
> -
> -
> -static int map_populate(int map_fd, int num)
> -{
> -	pcpu_map_value_t value[nr_cpus];
> -	int i, err;
> -	map_key_t key;
> -
> -	for (i = 0; i < nr_cpus; i++)
> -		bpf_percpu(value, i) = FILL_VALUE;
> -
> -	for (key = 1; key <= num; key++) {
> -		err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST);
> -		if (!ASSERT_OK(err, "bpf_map_update_elem"))
> -			return -1;
> -	}
> -
> -	return 0;
> -}
> -
> -static struct test_map_init *setup(enum bpf_map_type map_type, int map_sz,
> -			    int *map_fd, int populate)
> -{
> -	struct test_map_init *skel;
> -	int err;
> -
> -	skel = test_map_init__open();
> -	if (!ASSERT_OK_PTR(skel, "skel_open"))
> -		return NULL;
> -
> -	err = bpf_map__set_type(skel->maps.hashmap1, map_type);
> -	if (!ASSERT_OK(err, "bpf_map__set_type"))
> -		goto error;
> -
> -	err = bpf_map__set_max_entries(skel->maps.hashmap1, map_sz);
> -	if (!ASSERT_OK(err, "bpf_map__set_max_entries"))
> -		goto error;
> -
> -	err = test_map_init__load(skel);
> -	if (!ASSERT_OK(err, "skel_load"))
> -		goto error;
> -
> -	*map_fd = bpf_map__fd(skel->maps.hashmap1);
> -	if (CHECK(*map_fd < 0, "bpf_map__fd", "failed\n"))
> -		goto error;
> -
> -	err = map_populate(*map_fd, populate);
> -	if (!ASSERT_OK(err, "map_populate"))
> -		goto error_map;
> -
> -	return skel;
> -
> -error_map:
> -	close(*map_fd);
> -error:
> -	test_map_init__destroy(skel);
> -	return NULL;
> -}
> -
> -/* executes bpf program that updates map with key, value */
> -static int prog_run_insert_elem(struct test_map_init *skel, map_key_t key,
> -				map_value_t value)
> -{
> -	struct test_map_init__bss *bss;
> -
> -	bss = skel->bss;
> -
> -	bss->inKey = key;
> -	bss->inValue = value;
> -	bss->inPid = getpid();
> -
> -	if (!ASSERT_OK(test_map_init__attach(skel), "skel_attach"))
> -		return -1;
> -
> -	/* Let tracepoint trigger */
> -	syscall(__NR_getpgid);
> -
> -	test_map_init__detach(skel);
> -
> -	return 0;
> -}
> -
> -static int check_values_one_cpu(pcpu_map_value_t *value, map_value_t expected)
> -{
> -	int i, nzCnt = 0;
> -	map_value_t val;
> -
> -	for (i = 0; i < nr_cpus; i++) {
> -		val = bpf_percpu(value, i);
> -		if (val) {
> -			if (CHECK(val != expected, "map value",
> -				  "unexpected for cpu %d: 0x%llx\n", i, val))
> -				return -1;
> -			nzCnt++;
> -		}
> -	}
> -
> -	if (CHECK(nzCnt != 1, "map value", "set for %d CPUs instead of 1!\n",
> -		  nzCnt))
> -		return -1;
> -
> -	return 0;
> -}
> -
> -/* Add key=1 elem with values set for all CPUs
> - * Delete elem key=1
> - * Run bpf prog that inserts new key=1 elem with value=0x1234
> - *   (bpf prog can only set value for current CPU)
> - * Lookup Key=1 and check value is as expected for all CPUs:
> - *   value set by bpf prog for one CPU, 0 for all others
> - */
> -static void test_pcpu_map_init(void)
> -{
> -	pcpu_map_value_t value[nr_cpus];
> -	struct test_map_init *skel;
> -	int map_fd, err;
> -	map_key_t key;
> -
> -	/* max 1 elem in map so insertion is forced to reuse freed entry */
> -	skel = setup(BPF_MAP_TYPE_PERCPU_HASH, 1, &map_fd, 1);
> -	if (!ASSERT_OK_PTR(skel, "prog_setup"))
> -		return;
> -
> -	/* delete element so the entry can be re-used*/
> -	key = 1;
> -	err = bpf_map_delete_elem(map_fd, &key);
> -	if (!ASSERT_OK(err, "bpf_map_delete_elem"))
> -		goto cleanup;
> -
> -	/* run bpf prog that inserts new elem, re-using the slot just freed */
> -	err = prog_run_insert_elem(skel, key, TEST_VALUE);
> -	if (!ASSERT_OK(err, "prog_run_insert_elem"))
> -		goto cleanup;
> -
> -	/* check that key=1 was re-created by bpf prog */
> -	err = bpf_map_lookup_elem(map_fd, &key, value);
> -	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
> -		goto cleanup;
> -
> -	/* and has expected values */
> -	check_values_one_cpu(value, TEST_VALUE);
> -
> -cleanup:
> -	test_map_init__destroy(skel);
> -}
> -
> -/* Add key=1 and key=2 elems with values set for all CPUs
> - * Run bpf prog that inserts new key=3 elem
> - *   (only for current cpu; other cpus should have initial value = 0)
> - * Lookup Key=1 and check value is as expected for all CPUs
> - */
> -static void test_pcpu_lru_map_init(void)
> -{
> -	pcpu_map_value_t value[nr_cpus];
> -	struct test_map_init *skel;
> -	int map_fd, err;
> -	map_key_t key;
> -
> -	/* Set up LRU map with 2 elements, values filled for all CPUs.
> -	 * With these 2 elements, the LRU map is full
> -	 */
> -	skel = setup(BPF_MAP_TYPE_LRU_PERCPU_HASH, 2, &map_fd, 2);
> -	if (!ASSERT_OK_PTR(skel, "prog_setup"))
> -		return;
> -
> -	/* run bpf prog that inserts new key=3 element, re-using LRU slot */
> -	key = 3;
> -	err = prog_run_insert_elem(skel, key, TEST_VALUE);
> -	if (!ASSERT_OK(err, "prog_run_insert_elem"))
> -		goto cleanup;
> -
> -	/* check that key=3 replaced one of earlier elements */
> -	err = bpf_map_lookup_elem(map_fd, &key, value);
> -	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
> -		goto cleanup;
> -
> -	/* and has expected values */
> -	check_values_one_cpu(value, TEST_VALUE);
> -
> -cleanup:
> -	test_map_init__destroy(skel);
> -}
> -
> -void test_map_init(void)
> -{
> -	nr_cpus = bpf_num_possible_cpus();
> -	if (nr_cpus <= 1) {
> -		printf("%s:SKIP: >1 cpu needed for this test\n", __func__);
> -		test__skip();
> -		return;
> -	}
> -
> -	if (test__start_subtest("pcpu_map_init"))
> -		test_pcpu_map_init();
> -	if (test__start_subtest("pcpu_lru_map_init"))
> -		test_pcpu_lru_map_init();
> -}
> diff --git a/tools/testing/selftests/bpf/progs/test_map_init.c b/tools/testing/selftests/bpf/progs/test_map_init.c
> deleted file mode 100644
> index c89d28ead673..000000000000
> --- a/tools/testing/selftests/bpf/progs/test_map_init.c
> +++ /dev/null
> @@ -1,33 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
> -
> -#include "vmlinux.h"
> -#include <bpf/bpf_helpers.h>
> -
> -__u64 inKey = 0;
> -__u64 inValue = 0;
> -__u32 inPid = 0;
> -
> -struct {
> -	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
> -	__uint(max_entries, 2);
> -	__type(key, __u64);
> -	__type(value, __u64);
> -} hashmap1 SEC(".maps");
> -
> -
> -SEC("tp/syscalls/sys_enter_getpgid")
> -int sysenter_getpgid(const void *ctx)
> -{
> -	/* Just do it for once, when called from our own test prog. This
> -	 * ensures the map value is only updated for a single CPU.
> -	 */
> -	int cur_pid = bpf_get_current_pid_tgid() >> 32;
> -
> -	if (cur_pid == inPid)
> -		bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
> -
> -	return 0;
> -}
> -
> -char _license[] SEC("license") = "GPL";
> 


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