Merge branch 'bpf: RLIMIT_MEMLOCK cleanups'

Yafang Shao says:

====================

We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now.

This patchset cleanups the usage of RLIMIT_MEMLOCK in tools/bpf/,
tools/testing/selftests/bpf and samples/bpf. The file
tools/testing/selftests/bpf/bpf_rlimit.h is removed. The included header
sys/resource.h is removed from many files as it is useless in these files.

- v4: Squash patches and use customary subject prefixes. (Andrii)
- v3: Get rid of bpf_rlimit.h and fix some typos (Andrii)
- v2: Use libbpf_set_strict_mode instead. (Andrii)
- v1: https://lore.kernel.org/bpf/20220320060815.7716-2-laoar.shao@gmail.com/
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

9 files changed, 5 insertions, 39 deletions

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 0c1e06cf50b9..c740142c24d8 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -17,7 +17,6 @@
 #include <linux/magic.h>
 #include <net/if.h>
 #include <sys/mount.h>
-#include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/vfs.h>
 
@@ -119,13 +118,6 @@ static bool is_bpffs(char *path)
 	return (unsigned long)st_fs.f_type == BPF_FS_MAGIC;
 }
 
-void set_max_rlimit(void)
-{
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
-
-	setrlimit(RLIMIT_MEMLOCK, &rinf);
-}
-
 static int
 mnt_fs(const char *target, const char *type, char *buff, size_t bufflen)
 {
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index f041c4a6a1f2..be130e35462f 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -1136,8 +1136,6 @@ static int do_probe(int argc, char **argv)
 	__u32 ifindex = 0;
 	char *ifname;
 
-	set_max_rlimit();
-
 	while (argc) {
 		if (is_prefix(*argv, "kernel")) {
 			if (target != COMPONENT_UNSPEC) {
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index e81227761f5d..9062ef2b8767 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -507,9 +507,9 @@ int main(int argc, char **argv)
 		 * It will still be rejected if users use LIBBPF_STRICT_ALL
 		 * mode for loading generated skeleton.
 		 */
-		ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS);
-		if (ret)
-			p_err("failed to enable libbpf strict mode: %d", ret);
+		libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS);
+	} else {
+		libbpf_set_strict_mode(LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK);
 	}
 
 	argc -= optind;
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 6e9277ffc68c..aa99ffab451a 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -102,8 +102,6 @@ int detect_common_prefix(const char *arg, ...);
 void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep);
 void usage(void) __noreturn;
 
-void set_max_rlimit(void);
-
 int mount_tracefs(const char *target);
 
 struct obj_ref {
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index c26378f20831..877387ef79c7 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1342,8 +1342,6 @@ static int do_create(int argc, char **argv)
 		goto exit;
 	}
 
-	set_max_rlimit();
-
 	fd = bpf_map_create(map_type, map_name, key_size, value_size, max_entries, &attr);
 	if (fd < 0) {
 		p_err("map create failed: %s", strerror(errno));
diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
index bb6c969a114a..e2d00d3cd868 100644
--- a/tools/bpf/bpftool/pids.c
+++ b/tools/bpf/bpftool/pids.c
@@ -108,7 +108,6 @@ int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type)
 		p_err("failed to create hashmap for PID references");
 		return -1;
 	}
-	set_max_rlimit();
 
 	skel = pid_iter_bpf__open();
 	if (!skel) {
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 8643b37d4e43..5c2c63df92e8 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1604,8 +1604,6 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 		}
 	}
 
-	set_max_rlimit();
-
 	if (verifier_logs)
 		/* log_level1 + log_level2 + stats, but not stable UAPI */
 		open_opts.kernel_log_level = 1 + 2 + 4;
@@ -2303,7 +2301,6 @@ static int do_profile(int argc, char **argv)
 		}
 	}
 
-	set_max_rlimit();
 	err = profiler_bpf__load(profile_obj);
 	if (err) {
 		p_err("failed to load profile_obj");
diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index e08a6ff2866c..2535f079ed67 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -501,8 +501,6 @@ static int do_register(int argc, char **argv)
 	if (libbpf_get_error(obj))
 		return -1;
 
-	set_max_rlimit();
-
 	if (bpf_object__load(obj)) {
 		bpf_object__close(obj);
 		return -1;
diff --git a/tools/bpf/runqslower/runqslower.c b/tools/bpf/runqslower/runqslower.c
index d78f4148597f..83c5993a139a 100644
--- a/tools/bpf/runqslower/runqslower.c
+++ b/tools/bpf/runqslower/runqslower.c
@@ -4,7 +4,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/resource.h>
 #include <time.h>
 #include <bpf/libbpf.h>
 #include <bpf/bpf.h>
@@ -88,16 +87,6 @@ int libbpf_print_fn(enum libbpf_print_level level,
 	return vfprintf(stderr, format, args);
 }
 
-static int bump_memlock_rlimit(void)
-{
-	struct rlimit rlim_new = {
-		.rlim_cur	= RLIM_INFINITY,
-		.rlim_max	= RLIM_INFINITY,
-	};
-
-	return setrlimit(RLIMIT_MEMLOCK, &rlim_new);
-}
-
 void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
 {
 	const struct runq_event *e = data;
@@ -133,11 +122,8 @@ int main(int argc, char **argv)
 
 	libbpf_set_print(libbpf_print_fn);
 
-	err = bump_memlock_rlimit();
-	if (err) {
-		fprintf(stderr, "failed to increase rlimit: %d", err);
-		return 1;
-	}
+	/* Use libbpf 1.0 API mode */
+	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
 
 	obj = runqslower_bpf__open();
 	if (!obj) {