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From:   Roman Gushchin <guro@fb.com>
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To:     <bpf@vger.kernel.org>
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        Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
        <linux-kernel@vger.kernel.org>, Roman Gushchin <guro@fb.com>
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Subject: [PATCH bpf-next v2 29/35] bpf: libbpf: cleanup RLIMIT_MEMLOCK usage
Date:   Mon, 27 Jul 2020 11:45:00 -0700
Message-ID: <20200727184506.2279656-30-guro@fb.com>
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As bpf is not using memlock rlimit for memory accounting anymore,
let's remove the related code from libbpf.

Bpf operations can't fail because of exceeding the limit anymore.

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 tools/lib/bpf/libbpf.c | 31 +------------------------------
 tools/lib/bpf/libbpf.h |  5 -----
 2 files changed, 1 insertion(+), 35 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e51479d60285..841060f5cee3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -112,32 +112,6 @@ void libbpf_print(enum libbpf_print_level level, con=
st char *format, ...)
 	va_end(args);
 }
=20
-static void pr_perm_msg(int err)
-{
-	struct rlimit limit;
-	char buf[100];
-
-	if (err !=3D -EPERM || geteuid() !=3D 0)
-		return;
-
-	err =3D getrlimit(RLIMIT_MEMLOCK, &limit);
-	if (err)
-		return;
-
-	if (limit.rlim_cur =3D=3D RLIM_INFINITY)
-		return;
-
-	if (limit.rlim_cur < 1024)
-		snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
-	else if (limit.rlim_cur < 1024*1024)
-		snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
-	else
-		snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*=
1024));
-
-	pr_warn("permission error while running as root; try raising 'ulimit -l=
'? current value: %s\n",
-		buf);
-}
-
 #define STRERR_BUFSIZE  128
=20
 /* Copied from tools/perf/util/util.h */
@@ -3420,8 +3394,7 @@ bpf_object__probe_loading(struct bpf_object *obj)
 		cp =3D libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
 		pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF "
 			"program. Make sure your kernel supports BPF "
-			"(CONFIG_BPF_SYSCALL=3Dy) and/or that RLIMIT_MEMLOCK is "
-			"set to big enough value.\n", __func__, cp, ret);
+			"(CONFIG_BPF_SYSCALL=3Dy)", __func__, cp, ret);
 		return -ret;
 	}
 	close(ret);
@@ -3918,7 +3891,6 @@ bpf_object__create_maps(struct bpf_object *obj)
 err_out:
 	cp =3D libbpf_strerror_r(err, errmsg, sizeof(errmsg));
 	pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err);
-	pr_perm_msg(err);
 	for (j =3D 0; j < i; j++)
 		zclose(obj->maps[j].fd);
 	return err;
@@ -5419,7 +5391,6 @@ load_program(struct bpf_program *prog, struct bpf_i=
nsn *insns, int insns_cnt,
 	ret =3D -errno;
 	cp =3D libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
 	pr_warn("load bpf program failed: %s\n", cp);
-	pr_perm_msg(ret);
=20
 	if (log_buf && log_buf[0] !=3D '\0') {
 		ret =3D -LIBBPF_ERRNO__VERIFY;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c6813791fa7e..8d2f1194cb02 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -610,11 +610,6 @@ bpf_prog_linfo__lfind(const struct bpf_prog_linfo *p=
rog_linfo,
=20
 /*
  * Probe for supported system features
- *
- * Note that running many of these probes in a short amount of time can =
cause
- * the kernel to reach the maximal size of lockable memory allowed for t=
he
- * user, causing subsequent probes to fail. In this case, the caller may=
 want
- * to adjust that limit with setrlimit().
  */
 LIBBPF_API bool bpf_probe_prog_type(enum bpf_prog_type prog_type,
 				    __u32 ifindex);
--=20
2.26.2