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Date:   Mon, 17 Apr 2023 18:40:26 -0700
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Message-ID: <20230418014037.2412394-27-drosen@google.com>
Subject: [RFC PATCH v3 26/37] bpf: Increase struct_op limits
From:   Daniel Rosenberg <drosen@google.com>
To:     Miklos Szeredi <miklos@szeredi.hu>, bpf@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>
Cc:     Amir Goldstein <amir73il@gmail.com>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Joanne Koong <joannelkoong@gmail.com>,
        Mykola Lysenko <mykolal@fb.com>, kernel-team@android.com,
        Daniel Rosenberg <drosen@google.com>
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Precedence: bulk

Fuse bpf goes a bit past the '64' limit here, although in reality, this
limit seems to be more like 37. After 37, we start overrunning the
safety checks while setting up the trampoline.

This simply doubles some of these values. This will have the same issue,
as we'll run out of space way before hitting the 128 limit, but for now
that unblocks fuse-bpf.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 include/linux/bpf.h         | 2 +-
 kernel/bpf/bpf_struct_ops.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 18b592fde896..c006f823e634 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1537,7 +1537,7 @@ struct bpf_link_primer {
 struct bpf_struct_ops_value;
 struct btf_member;
 
-#define BPF_STRUCT_OPS_MAX_NR_MEMBERS 64
+#define BPF_STRUCT_OPS_MAX_NR_MEMBERS 128
 struct bpf_struct_ops {
 	const struct bpf_verifier_ops *verifier_ops;
 	int (*init)(struct btf *btf);
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index d3f0a4825fa6..deb9eecaf1e4 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -417,7 +417,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 	udata = &uvalue->data;
 	kdata = &kvalue->data;
 	image = st_map->image;
-	image_end = st_map->image + PAGE_SIZE;
+	image_end = st_map->image + 2 * PAGE_SIZE;
 
 	for_each_member(i, t, member) {
 		const struct btf_type *mtype, *ptype;
@@ -688,7 +688,7 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
 	st_map->links =
 		bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *),
 				   NUMA_NO_NODE);
-	st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
+	st_map->image = bpf_jit_alloc_exec(2 * PAGE_SIZE);
 	if (!st_map->uvalue || !st_map->links || !st_map->image) {
 		__bpf_struct_ops_map_free(map);
 		return ERR_PTR(-ENOMEM);
-- 
2.40.0.634.g4ca3ef3211-goog