From b822a139e3997a0a09da940e5c88ea505459e81f Mon Sep 17 00:00:00 2001
From: Hou Tao <houtao1@huawei.com>
Date: Wed, 16 Nov 2022 15:23:48 +0800
Subject: [PATCH] libbpf: Use page size as max_entries when probing ring buffer
 map

Using page size as max_entries when probing ring buffer map, else the
probe may fail on host with 64KB page size (e.g., an ARM64 host).

After the fix, the output of "bpftool feature" on above host will be
correct.

Before :
    eBPF map_type ringbuf is NOT available
    eBPF map_type user_ringbuf is NOT available

After :
    eBPF map_type ringbuf is available
    eBPF map_type user_ringbuf is available

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com
---
 src/libbpf_probes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libbpf_probes.c b/src/libbpf_probes.c
index 97b06ce..49c36cb 100644
--- a/src/libbpf_probes.c
+++ b/src/libbpf_probes.c
@@ -289,7 +289,7 @@ static int probe_map_create(enum bpf_map_type map_type, __u32 ifindex)
 	case BPF_MAP_TYPE_RINGBUF:
 		key_size = 0;
 		value_size = 0;
-		max_entries = 4096;
+		max_entries = sysconf(_SC_PAGE_SIZE);
 		break;
 	case BPF_MAP_TYPE_STRUCT_OPS:
 		/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
-- 
2.33.0