bpf: enable cgroup local storage map pretty print with kind_flag

Commit 970289fc0a83 ("bpf: add bpffs pretty print for cgroup
local storage maps") added bpffs pretty print for cgroup
local storage maps. The commit worked for struct without kind_flag
set.

This patch refactored and made pretty print also work
with kind_flag set for the struct.

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 58000d7e06e36019c9f1b02011ba463163351b92..12502e25e76764c183d107b5bf00c76a02f3e6af 100644 (file)
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -7,6 +7,7 @@
 #include <linux/types.h>
 
 struct btf;
+struct btf_member;
 struct btf_type;
 union bpf_attr;
 
@@ -46,7 +47,9 @@ void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
                       struct seq_file *m);
 int btf_get_fd_by_id(u32 id);
 u32 btf_id(const struct btf *btf);
-bool btf_type_is_reg_int(const struct btf_type *t, u32 expected_size);
+bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
+                          const struct btf_member *m,
+                          u32 expected_offset, u32 expected_size);
 
 #ifdef CONFIG_BPF_SYSCALL
 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 93b6905e3a9be67700037c87ea07819004e882a9..e804b26a0506a64e75ab36f38f9b063e8c6a9041 100644 (file)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -546,22 +546,41 @@ static bool btf_type_int_is_regular(const struct btf_type *t)
 }
 
 /*
- * Check that given type is a regular int and has the expected size.
+ * Check that given struct member is a regular int with expected
+ * offset and size.
  */
-bool btf_type_is_reg_int(const struct btf_type *t, u32 expected_size)
+bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
+                          const struct btf_member *m,
+                          u32 expected_offset, u32 expected_size)
 {
-       u8 nr_bits, nr_bytes;
-       u32 int_data;
+       const struct btf_type *t;
+       u32 id, int_data;
+       u8 nr_bits;
 
-       if (!btf_type_is_int(t))
+       id = m->type;
+       t = btf_type_id_size(btf, &id, NULL);
+       if (!t || !btf_type_is_int(t))
                return false;
 
        int_data = btf_type_int(t);
        nr_bits = BTF_INT_BITS(int_data);
-       nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
-       if (BITS_PER_BYTE_MASKED(nr_bits) ||
-           BTF_INT_OFFSET(int_data) ||
-           nr_bytes != expected_size)
+       if (btf_type_kflag(s)) {
+               u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
+               u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
+
+               /* if kflag set, int should be a regular int and
+                * bit offset should be at byte boundary.
+                */
+               return !bitfield_size &&
+                      BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
+                      BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
+       }
+
+       if (BTF_INT_OFFSET(int_data) ||
+           BITS_PER_BYTE_MASKED(m->offset) ||
+           BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
+           BITS_PER_BYTE_MASKED(nr_bits) ||
+           BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
                return false;
 
        return true;

diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 5eca03da0989da5c99e67b08775857ab2b7c2a40..07a34ef562a064ff3413f91a3dc7cc72e3301204 100644 (file)
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -315,9 +315,8 @@ static int cgroup_storage_check_btf(const struct bpf_map *map,
                                    const struct btf_type *key_type,
                                    const struct btf_type *value_type)
 {
-       const struct btf_type *t;
        struct btf_member *m;
-       u32 id, size;
+       u32 offset, size;
 
        /* Key is expected to be of struct bpf_cgroup_storage_key type,
         * which is:
@@ -338,25 +337,17 @@ static int cgroup_storage_check_btf(const struct bpf_map *map,
         * The first field must be a 64 bit integer at 0 offset.
         */
        m = (struct btf_member *)(key_type + 1);
-       if (m->offset)
-               return -EINVAL;
-       id = m->type;
-       t = btf_type_id_size(btf, &id, NULL);
        size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, cgroup_inode_id);
-       if (!t || !btf_type_is_reg_int(t, size))
+       if (!btf_member_is_reg_int(btf, key_type, m, 0, size))
                return -EINVAL;
 
        /*
         * The second field must be a 32 bit integer at 64 bit offset.
         */
        m++;
-       if (m->offset != offsetof(struct bpf_cgroup_storage_key, attach_type) *
-           BITS_PER_BYTE)
-               return -EINVAL;
-       id = m->type;
-       t = btf_type_id_size(btf, &id, NULL);
+       offset = offsetof(struct bpf_cgroup_storage_key, attach_type);
        size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, attach_type);
-       if (!t || !btf_type_is_reg_int(t, size))
+       if (!btf_member_is_reg_int(btf, key_type, m, offset, size))
                return -EINVAL;
 
        return 0;