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samples: bpf: Replace attach_tracepoint() to attach() in xdp_redirect_cpu 

>From commit d7a18ea7e8 ("libbpf: Add generic bpf_program__attach()"),
for some BPF programs, it is now possible to attach BPF programs
with __attach() instead of explicitly calling __attach_<type>().

This commit refactors the __attach_tracepoint() with libbpf's generic
__attach() method. In addition, this refactors the logic of setting
the map FD to simplify the code. Also, the missing removal of
bpf_load.o in Makefile has been fixed.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201010181734.1109-3-danieltimlee@gmail.com
This commit is contained in:
Daniel T. Lee 2020-10-11 03:17:33 +09:00 committed by Alexei Starovoitov
parent 8ac91df6de
commit 151936bf51
2 changed files with 71 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
samples/bpf/Makefile
View File

@ -98,7 +98,7 @@ test_map_in_map-objs := test_map_in_map_user.o
per_socket_stats_example-objs := cookie_uid_helper_example.o
xdp_redirect-objs := xdp_redirect_user.o
xdp_redirect_map-objs := xdp_redirect_map_user.o
xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
xdp_redirect_cpu-objs := xdp_redirect_cpu_user.o
xdp_monitor-objs := xdp_monitor_user.o
xdp_rxq_info-objs := xdp_rxq_info_user.o
syscall_tp-objs := syscall_tp_user.o

149
samples/bpf/xdp_redirect_cpu_user.c
View File

@ -37,18 +37,35 @@ static __u32 prog_id;
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int n_cpus;
static int cpu_map_fd;
static int rx_cnt_map_fd;
static int redirect_err_cnt_map_fd;
static int cpumap_enqueue_cnt_map_fd;
static int cpumap_kthread_cnt_map_fd;
static int cpus_available_map_fd;
static int cpus_count_map_fd;
static int cpus_iterator_map_fd;
static int exception_cnt_map_fd;
enum map_type {
CPU_MAP,
RX_CNT,
REDIRECT_ERR_CNT,
CPUMAP_ENQUEUE_CNT,
CPUMAP_KTHREAD_CNT,
CPUS_AVAILABLE,
CPUS_COUNT,
CPUS_ITERATOR,
EXCEPTION_CNT,
};
static const char *const map_type_strings[] = {
[CPU_MAP] = "cpu_map",
[RX_CNT] = "rx_cnt",
[REDIRECT_ERR_CNT] = "redirect_err_cnt",
[CPUMAP_ENQUEUE_CNT] = "cpumap_enqueue_cnt",
[CPUMAP_KTHREAD_CNT] = "cpumap_kthread_cnt",
[CPUS_AVAILABLE] = "cpus_available",
[CPUS_COUNT] = "cpus_count",
[CPUS_ITERATOR] = "cpus_iterator",
[EXCEPTION_CNT] = "exception_cnt",
};
#define NUM_TP 5
struct bpf_link *tp_links[NUM_TP] = { 0 };
#define NUM_MAP 9
struct bpf_link *tp_links[NUM_TP] = {};
static int map_fds[NUM_MAP];
static int tp_cnt = 0;
/* Exit return codes */
@ -527,20 +544,20 @@ static void stats_collect(struct stats_record *rec)
{
int fd, i;
fd = rx_cnt_map_fd;
fd = map_fds[RX_CNT];
map_collect_percpu(fd, 0, &rec->rx_cnt);
fd = redirect_err_cnt_map_fd;
fd = map_fds[REDIRECT_ERR_CNT];
map_collect_percpu(fd, 1, &rec->redir_err);
fd = cpumap_enqueue_cnt_map_fd;
fd = map_fds[CPUMAP_ENQUEUE_CNT];
for (i = 0; i < n_cpus; i++)
map_collect_percpu(fd, i, &rec->enq[i]);
fd = cpumap_kthread_cnt_map_fd;
fd = map_fds[CPUMAP_KTHREAD_CNT];
map_collect_percpu(fd, 0, &rec->kthread);
fd = exception_cnt_map_fd;
fd = map_fds[EXCEPTION_CNT];
map_collect_percpu(fd, 0, &rec->exception);
}
@ -565,7 +582,7 @@ static int create_cpu_entry(__u32 cpu, struct bpf_cpumap_val *value,
/* Add a CPU entry to cpumap, as this allocate a cpu entry in
* the kernel for the cpu.
*/
ret = bpf_map_update_elem(cpu_map_fd, &cpu, value, 0);
ret = bpf_map_update_elem(map_fds[CPU_MAP], &cpu, value, 0);
if (ret) {
fprintf(stderr, "Create CPU entry failed (err:%d)\n", ret);
exit(EXIT_FAIL_BPF);
@ -574,21 +591,21 @@ static int create_cpu_entry(__u32 cpu, struct bpf_cpumap_val *value,
/* Inform bpf_prog's that a new CPU is available to select
* from via some control maps.
*/
ret = bpf_map_update_elem(cpus_available_map_fd, &avail_idx, &cpu, 0);
ret = bpf_map_update_elem(map_fds[CPUS_AVAILABLE], &avail_idx, &cpu, 0);
if (ret) {
fprintf(stderr, "Add to avail CPUs failed\n");
exit(EXIT_FAIL_BPF);
}
/* When not replacing/updating existing entry, bump the count */
ret = bpf_map_lookup_elem(cpus_count_map_fd, &key, &curr_cpus_count);
ret = bpf_map_lookup_elem(map_fds[CPUS_COUNT], &key, &curr_cpus_count);
if (ret) {
fprintf(stderr, "Failed reading curr cpus_count\n");
exit(EXIT_FAIL_BPF);
}
if (new) {
curr_cpus_count++;
ret = bpf_map_update_elem(cpus_count_map_fd, &key,
ret = bpf_map_update_elem(map_fds[CPUS_COUNT], &key,
&curr_cpus_count, 0);
if (ret) {
fprintf(stderr, "Failed write curr cpus_count\n");
@ -612,7 +629,7 @@ static void mark_cpus_unavailable(void)
int ret, i;
for (i = 0; i < n_cpus; i++) {
ret = bpf_map_update_elem(cpus_available_map_fd, &i,
ret = bpf_map_update_elem(map_fds[CPUS_AVAILABLE], &i,
&invalid_cpu, 0);
if (ret) {
fprintf(stderr, "Failed marking CPU unavailable\n");
@ -665,68 +682,37 @@ static void stats_poll(int interval, bool use_separators, char *prog_name,
free_stats_record(prev);
}
static struct bpf_link * attach_tp(struct bpf_object *obj,
const char *tp_category,
const char* tp_name)
static int init_tracepoints(struct bpf_object *obj)
{
struct bpf_program *prog;
struct bpf_link *link;
char sec_name[PATH_MAX];
int len;
len = snprintf(sec_name, PATH_MAX, "tracepoint/%s/%s",
tp_category, tp_name);
if (len < 0)
exit(EXIT_FAIL);
bpf_object__for_each_program(prog, obj) {
if (bpf_program__is_tracepoint(prog) != true)
continue;
prog = bpf_object__find_program_by_title(obj, sec_name);
if (!prog) {
fprintf(stderr, "ERR: finding progsec: %s\n", sec_name);
exit(EXIT_FAIL_BPF);
tp_links[tp_cnt] = bpf_program__attach(prog);
if (libbpf_get_error(tp_links[tp_cnt])) {
tp_links[tp_cnt] = NULL;
return -EINVAL;
}
tp_cnt++;
}
link = bpf_program__attach_tracepoint(prog, tp_category, tp_name);
if (libbpf_get_error(link))
exit(EXIT_FAIL_BPF);
return link;
}
static void init_tracepoints(struct bpf_object *obj) {
tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_redirect_err");
tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_redirect_map_err");
tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_exception");
tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_cpumap_enqueue");
tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_cpumap_kthread");
return 0;
}
static int init_map_fds(struct bpf_object *obj)
{
/* Maps updated by tracepoints */
redirect_err_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "redirect_err_cnt");
exception_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "exception_cnt");
cpumap_enqueue_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpumap_enqueue_cnt");
cpumap_kthread_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpumap_kthread_cnt");
enum map_type type;
/* Maps used by XDP */
rx_cnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rx_cnt");
cpu_map_fd = bpf_object__find_map_fd_by_name(obj, "cpu_map");
cpus_available_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpus_available");
cpus_count_map_fd = bpf_object__find_map_fd_by_name(obj, "cpus_count");
cpus_iterator_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpus_iterator");
for (type = 0; type < NUM_MAP; type++) {
map_fds[type] =
bpf_object__find_map_fd_by_name(obj,
map_type_strings[type]);
if (cpu_map_fd < 0 || rx_cnt_map_fd < 0 ||
redirect_err_cnt_map_fd < 0 || cpumap_enqueue_cnt_map_fd < 0 ||
cpumap_kthread_cnt_map_fd < 0 || cpus_available_map_fd < 0 ||
cpus_count_map_fd < 0 || cpus_iterator_map_fd < 0 ||
exception_cnt_map_fd < 0)
return -ENOENT;
if (map_fds[type] < 0)
return -ENOENT;
}
return 0;
}
@ -795,13 +781,13 @@ int main(int argc, char **argv)
bool stress_mode = false;
struct bpf_program *prog;
struct bpf_object *obj;
int err = EXIT_FAIL;
char filename[256];
int added_cpus = 0;
int longindex = 0;
int interval = 2;
int add_cpu = -1;
int opt, err;
int prog_fd;
int opt, prog_fd;
int *cpu, i;
__u32 qsize;
@ -824,24 +810,29 @@ int main(int argc, char **argv)
}
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return EXIT_FAIL;
return err;
if (prog_fd < 0) {
fprintf(stderr, "ERR: bpf_prog_load_xattr: %s\n",
strerror(errno));
return EXIT_FAIL;
return err;
}
init_tracepoints(obj);
if (init_tracepoints(obj) < 0) {
fprintf(stderr, "ERR: bpf_program__attach failed\n");
return err;
}
if (init_map_fds(obj) < 0) {
fprintf(stderr, "bpf_object__find_map_fd_by_name failed\n");
return EXIT_FAIL;
return err;
}
mark_cpus_unavailable();
cpu = malloc(n_cpus * sizeof(int));
if (!cpu) {
fprintf(stderr, "failed to allocate cpu array\n");
return EXIT_FAIL;
return err;
}
memset(cpu, 0, n_cpus * sizeof(int));
@ -960,14 +951,12 @@ int main(int argc, char **argv)
prog = bpf_object__find_program_by_title(obj, prog_name);
if (!prog) {
fprintf(stderr, "bpf_object__find_program_by_title failed\n");
err = EXIT_FAIL;
goto out;
}
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
fprintf(stderr, "bpf_program__fd failed\n");
err = EXIT_FAIL;
goto out;
}
@ -986,6 +975,8 @@ int main(int argc, char **argv)
stats_poll(interval, use_separators, prog_name, mprog_name,
&value, stress_mode);
err = EXIT_OK;
out:
free(cpu);
return err;