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authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-28 16:02:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-28 16:02:33 -0800
commitbd2463ac7d7ec51d432f23bf0e893fb371a908cd (patch)
tree3da32c23be83adb9d9bda7e51b51fa39f69f2447 /kernel/bpf/bpf_struct_ops.c
parenta78208e2436963d0b2c7d186277d6e1a9755029a (diff)
parentf76e4c167ea2212e23c15ee7e601a865e822c291 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller: 1) Add WireGuard 2) Add HE and TWT support to ath11k driver, from John Crispin. 3) Add ESP in TCP encapsulation support, from Sabrina Dubroca. 4) Add variable window congestion control to TIPC, from Jon Maloy. 5) Add BCM84881 PHY driver, from Russell King. 6) Start adding netlink support for ethtool operations, from Michal Kubecek. 7) Add XDP drop and TX action support to ena driver, from Sameeh Jubran. 8) Add new ipv4 route notifications so that mlxsw driver does not have to handle identical routes itself. From Ido Schimmel. 9) Add BPF dynamic program extensions, from Alexei Starovoitov. 10) Support RX and TX timestamping in igc, from Vinicius Costa Gomes. 11) Add support for macsec HW offloading, from Antoine Tenart. 12) Add initial support for MPTCP protocol, from Christoph Paasch, Matthieu Baerts, Florian Westphal, Peter Krystad, and many others. 13) Add Octeontx2 PF support, from Sunil Goutham, Geetha sowjanya, Linu Cherian, and others. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1469 commits) net: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC udp: segment looped gso packets correctly netem: change mailing list qed: FW 8.42.2.0 debug features qed: rt init valid initialization changed qed: Debug feature: ilt and mdump qed: FW 8.42.2.0 Add fw overlay feature qed: FW 8.42.2.0 HSI changes qed: FW 8.42.2.0 iscsi/fcoe changes qed: Add abstraction for different hsi values per chip qed: FW 8.42.2.0 Additional ll2 type qed: Use dmae to write to widebus registers in fw_funcs qed: FW 8.42.2.0 Parser offsets modified qed: FW 8.42.2.0 Queue Manager changes qed: FW 8.42.2.0 Expose new registers and change windows qed: FW 8.42.2.0 Internal ram offsets modifications MAINTAINERS: Add entry for Marvell OcteonTX2 Physical Function driver Documentation: net: octeontx2: Add RVU HW and drivers overview octeontx2-pf: ethtool RSS config support octeontx2-pf: Add basic ethtool support ...
Diffstat (limited to 'kernel/bpf/bpf_struct_ops.c')
-rw-r--r--kernel/bpf/bpf_struct_ops.c634
1 files changed, 634 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
new file mode 100644
index 000000000000..8ad1c9ea26b2
--- /dev/null
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/slab.h>
+#include <linux/numa.h>
+#include <linux/seq_file.h>
+#include <linux/refcount.h>
+#include <linux/mutex.h>
+
+enum bpf_struct_ops_state {
+ BPF_STRUCT_OPS_STATE_INIT,
+ BPF_STRUCT_OPS_STATE_INUSE,
+ BPF_STRUCT_OPS_STATE_TOBEFREE,
+};
+
+#define BPF_STRUCT_OPS_COMMON_VALUE \
+ refcount_t refcnt; \
+ enum bpf_struct_ops_state state
+
+struct bpf_struct_ops_value {
+ BPF_STRUCT_OPS_COMMON_VALUE;
+ char data[0] ____cacheline_aligned_in_smp;
+};
+
+struct bpf_struct_ops_map {
+ struct bpf_map map;
+ const struct bpf_struct_ops *st_ops;
+ /* protect map_update */
+ struct mutex lock;
+ /* progs has all the bpf_prog that is populated
+ * to the func ptr of the kernel's struct
+ * (in kvalue.data).
+ */
+ struct bpf_prog **progs;
+ /* image is a page that has all the trampolines
+ * that stores the func args before calling the bpf_prog.
+ * A PAGE_SIZE "image" is enough to store all trampoline for
+ * "progs[]".
+ */
+ void *image;
+ /* uvalue->data stores the kernel struct
+ * (e.g. tcp_congestion_ops) that is more useful
+ * to userspace than the kvalue. For example,
+ * the bpf_prog's id is stored instead of the kernel
+ * address of a func ptr.
+ */
+ struct bpf_struct_ops_value *uvalue;
+ /* kvalue.data stores the actual kernel's struct
+ * (e.g. tcp_congestion_ops) that will be
+ * registered to the kernel subsystem.
+ */
+ struct bpf_struct_ops_value kvalue;
+};
+
+#define VALUE_PREFIX "bpf_struct_ops_"
+#define VALUE_PREFIX_LEN (sizeof(VALUE_PREFIX) - 1)
+
+/* bpf_struct_ops_##_name (e.g. bpf_struct_ops_tcp_congestion_ops) is
+ * the map's value exposed to the userspace and its btf-type-id is
+ * stored at the map->btf_vmlinux_value_type_id.
+ *
+ */
+#define BPF_STRUCT_OPS_TYPE(_name) \
+extern struct bpf_struct_ops bpf_##_name; \
+ \
+struct bpf_struct_ops_##_name { \
+ BPF_STRUCT_OPS_COMMON_VALUE; \
+ struct _name data ____cacheline_aligned_in_smp; \
+};
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+
+enum {
+#define BPF_STRUCT_OPS_TYPE(_name) BPF_STRUCT_OPS_TYPE_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+ __NR_BPF_STRUCT_OPS_TYPE,
+};
+
+static struct bpf_struct_ops * const bpf_struct_ops[] = {
+#define BPF_STRUCT_OPS_TYPE(_name) \
+ [BPF_STRUCT_OPS_TYPE_##_name] = &bpf_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+};
+
+const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
+};
+
+const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
+};
+
+static const struct btf_type *module_type;
+
+void bpf_struct_ops_init(struct btf *btf)
+{
+ s32 type_id, value_id, module_id;
+ const struct btf_member *member;
+ struct bpf_struct_ops *st_ops;
+ struct bpf_verifier_log log = {};
+ const struct btf_type *t;
+ char value_name[128];
+ const char *mname;
+ u32 i, j;
+
+ /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
+#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct bpf_struct_ops_##_name);
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+
+ module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
+ if (module_id < 0) {
+ pr_warn("Cannot find struct module in btf_vmlinux\n");
+ return;
+ }
+ module_type = btf_type_by_id(btf, module_id);
+
+ for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ st_ops = bpf_struct_ops[i];
+
+ if (strlen(st_ops->name) + VALUE_PREFIX_LEN >=
+ sizeof(value_name)) {
+ pr_warn("struct_ops name %s is too long\n",
+ st_ops->name);
+ continue;
+ }
+ sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
+
+ value_id = btf_find_by_name_kind(btf, value_name,
+ BTF_KIND_STRUCT);
+ if (value_id < 0) {
+ pr_warn("Cannot find struct %s in btf_vmlinux\n",
+ value_name);
+ continue;
+ }
+
+ type_id = btf_find_by_name_kind(btf, st_ops->name,
+ BTF_KIND_STRUCT);
+ if (type_id < 0) {
+ pr_warn("Cannot find struct %s in btf_vmlinux\n",
+ st_ops->name);
+ continue;
+ }
+ t = btf_type_by_id(btf, type_id);
+ if (btf_type_vlen(t) > BPF_STRUCT_OPS_MAX_NR_MEMBERS) {
+ pr_warn("Cannot support #%u members in struct %s\n",
+ btf_type_vlen(t), st_ops->name);
+ continue;
+ }
+
+ for_each_member(j, t, member) {
+ const struct btf_type *func_proto;
+
+ mname = btf_name_by_offset(btf, member->name_off);
+ if (!*mname) {
+ pr_warn("anon member in struct %s is not supported\n",
+ st_ops->name);
+ break;
+ }
+
+ if (btf_member_bitfield_size(t, member)) {
+ pr_warn("bit field member %s in struct %s is not supported\n",
+ mname, st_ops->name);
+ break;
+ }
+
+ func_proto = btf_type_resolve_func_ptr(btf,
+ member->type,
+ NULL);
+ if (func_proto &&
+ btf_distill_func_proto(&log, btf,
+ func_proto, mname,
+ &st_ops->func_models[j])) {
+ pr_warn("Error in parsing func ptr %s in struct %s\n",
+ mname, st_ops->name);
+ break;
+ }
+ }
+
+ if (j == btf_type_vlen(t)) {
+ if (st_ops->init(btf)) {
+ pr_warn("Error in init bpf_struct_ops %s\n",
+ st_ops->name);
+ } else {
+ st_ops->type_id = type_id;
+ st_ops->type = t;
+ st_ops->value_id = value_id;
+ st_ops->value_type = btf_type_by_id(btf,
+ value_id);
+ }
+ }
+ }
+}
+
+extern struct btf *btf_vmlinux;
+
+static const struct bpf_struct_ops *
+bpf_struct_ops_find_value(u32 value_id)
+{
+ unsigned int i;
+
+ if (!value_id || !btf_vmlinux)
+ return NULL;
+
+ for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ if (bpf_struct_ops[i]->value_id == value_id)
+ return bpf_struct_ops[i];
+ }
+
+ return NULL;
+}
+
+const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
+{
+ unsigned int i;
+
+ if (!type_id || !btf_vmlinux)
+ return NULL;
+
+ for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ if (bpf_struct_ops[i]->type_id == type_id)
+ return bpf_struct_ops[i];
+ }
+
+ return NULL;
+}
+
+static int bpf_struct_ops_map_get_next_key(struct bpf_map *map, void *key,
+ void *next_key)
+{
+ if (key && *(u32 *)key == 0)
+ return -ENOENT;
+
+ *(u32 *)next_key = 0;
+ return 0;
+}
+
+int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
+ void *value)
+{
+ struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+ struct bpf_struct_ops_value *uvalue, *kvalue;
+ enum bpf_struct_ops_state state;
+
+ if (unlikely(*(u32 *)key != 0))
+ return -ENOENT;
+
+ kvalue = &st_map->kvalue;
+ /* Pair with smp_store_release() during map_update */
+ state = smp_load_acquire(&kvalue->state);
+ if (state == BPF_STRUCT_OPS_STATE_INIT) {
+ memset(value, 0, map->value_size);
+ return 0;
+ }
+
+ /* No lock is needed. state and refcnt do not need
+ * to be updated together under atomic context.
+ */
+ uvalue = (struct bpf_struct_ops_value *)value;
+ memcpy(uvalue, st_map->uvalue, map->value_size);
+ uvalue->state = state;
+ refcount_set(&uvalue->refcnt, refcount_read(&kvalue->refcnt));
+
+ return 0;
+}
+
+static void *bpf_struct_ops_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ return ERR_PTR(-EINVAL);
+}
+
+static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map)
+{
+ const struct btf_type *t = st_map->st_ops->type;
+ u32 i;
+
+ for (i = 0; i < btf_type_vlen(t); i++) {
+ if (st_map->progs[i]) {
+ bpf_prog_put(st_map->progs[i]);
+ st_map->progs[i] = NULL;
+ }
+ }
+}
+
+static int check_zero_holes(const struct btf_type *t, void *data)
+{
+ const struct btf_member *member;
+ u32 i, moff, msize, prev_mend = 0;
+ const struct btf_type *mtype;
+
+ for_each_member(i, t, member) {
+ moff = btf_member_bit_offset(t, member) / 8;
+ if (moff > prev_mend &&
+ memchr_inv(data + prev_mend, 0, moff - prev_mend))
+ return -EINVAL;
+
+ mtype = btf_type_by_id(btf_vmlinux, member->type);
+ mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
+ NULL, NULL);
+ if (IS_ERR(mtype))
+ return PTR_ERR(mtype);
+ prev_mend = moff + msize;
+ }
+
+ if (t->size > prev_mend &&
+ memchr_inv(data + prev_mend, 0, t->size - prev_mend))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+ const struct bpf_struct_ops *st_ops = st_map->st_ops;
+ struct bpf_struct_ops_value *uvalue, *kvalue;
+ const struct btf_member *member;
+ const struct btf_type *t = st_ops->type;
+ void *udata, *kdata;
+ int prog_fd, err = 0;
+ void *image;
+ u32 i;
+
+ if (flags)
+ return -EINVAL;
+
+ if (*(u32 *)key != 0)
+ return -E2BIG;
+
+ err = check_zero_holes(st_ops->value_type, value);
+ if (err)
+ return err;
+
+ uvalue = (struct bpf_struct_ops_value *)value;
+ err = check_zero_holes(t, uvalue->data);
+ if (err)
+ return err;
+
+ if (uvalue->state || refcount_read(&uvalue->refcnt))
+ return -EINVAL;
+
+ uvalue = (struct bpf_struct_ops_value *)st_map->uvalue;
+ kvalue = (struct bpf_struct_ops_value *)&st_map->kvalue;
+
+ mutex_lock(&st_map->lock);
+
+ if (kvalue->state != BPF_STRUCT_OPS_STATE_INIT) {
+ err = -EBUSY;
+ goto unlock;
+ }
+
+ memcpy(uvalue, value, map->value_size);
+
+ udata = &uvalue->data;
+ kdata = &kvalue->data;
+ image = st_map->image;
+
+ for_each_member(i, t, member) {
+ const struct btf_type *mtype, *ptype;
+ struct bpf_prog *prog;
+ u32 moff;
+
+ moff = btf_member_bit_offset(t, member) / 8;
+ ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
+ if (ptype == module_type) {
+ if (*(void **)(udata + moff))
+ goto reset_unlock;
+ *(void **)(kdata + moff) = BPF_MODULE_OWNER;
+ continue;
+ }
+
+ err = st_ops->init_member(t, member, kdata, udata);
+ if (err < 0)
+ goto reset_unlock;
+
+ /* The ->init_member() has handled this member */
+ if (err > 0)
+ continue;
+
+ /* If st_ops->init_member does not handle it,
+ * we will only handle func ptrs and zero-ed members
+ * here. Reject everything else.
+ */
+
+ /* All non func ptr member must be 0 */
+ if (!ptype || !btf_type_is_func_proto(ptype)) {
+ u32 msize;
+
+ mtype = btf_type_by_id(btf_vmlinux, member->type);
+ mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
+ NULL, NULL);
+ if (IS_ERR(mtype)) {
+ err = PTR_ERR(mtype);
+ goto reset_unlock;
+ }
+
+ if (memchr_inv(udata + moff, 0, msize)) {
+ err = -EINVAL;
+ goto reset_unlock;
+ }
+
+ continue;
+ }
+
+ prog_fd = (int)(*(unsigned long *)(udata + moff));
+ /* Similar check as the attr->attach_prog_fd */
+ if (!prog_fd)
+ continue;
+
+ prog = bpf_prog_get(prog_fd);
+ if (IS_ERR(prog)) {
+ err = PTR_ERR(prog);
+ goto reset_unlock;
+ }
+ st_map->progs[i] = prog;
+
+ if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
+ prog->aux->attach_btf_id != st_ops->type_id ||
+ prog->expected_attach_type != i) {
+ err = -EINVAL;
+ goto reset_unlock;
+ }
+
+ err = arch_prepare_bpf_trampoline(image,
+ st_map->image + PAGE_SIZE,
+ &st_ops->func_models[i], 0,
+ &prog, 1, NULL, 0, NULL);
+ if (err < 0)
+ goto reset_unlock;
+
+ *(void **)(kdata + moff) = image;
+ image += err;
+
+ /* put prog_id to udata */
+ *(unsigned long *)(udata + moff) = prog->aux->id;
+ }
+
+ refcount_set(&kvalue->refcnt, 1);
+ bpf_map_inc(map);
+
+ set_memory_ro((long)st_map->image, 1);
+ set_memory_x((long)st_map->image, 1);
+ err = st_ops->reg(kdata);
+ if (likely(!err)) {
+ /* Pair with smp_load_acquire() during lookup_elem().
+ * It ensures the above udata updates (e.g. prog->aux->id)
+ * can be seen once BPF_STRUCT_OPS_STATE_INUSE is set.
+ */
+ smp_store_release(&kvalue->state, BPF_STRUCT_OPS_STATE_INUSE);
+ goto unlock;
+ }
+
+ /* Error during st_ops->reg(). It is very unlikely since
+ * the above init_member() should have caught it earlier
+ * before reg(). The only possibility is if there was a race
+ * in registering the struct_ops (under the same name) to
+ * a sub-system through different struct_ops's maps.
+ */
+ set_memory_nx((long)st_map->image, 1);
+ set_memory_rw((long)st_map->image, 1);
+ bpf_map_put(map);
+
+reset_unlock:
+ bpf_struct_ops_map_put_progs(st_map);
+ memset(uvalue, 0, map->value_size);
+ memset(kvalue, 0, map->value_size);
+unlock:
+ mutex_unlock(&st_map->lock);
+ return err;
+}
+
+static int bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
+{
+ enum bpf_struct_ops_state prev_state;
+ struct bpf_struct_ops_map *st_map;
+
+ st_map = (struct bpf_struct_ops_map *)map;
+ prev_state = cmpxchg(&st_map->kvalue.state,
+ BPF_STRUCT_OPS_STATE_INUSE,
+ BPF_STRUCT_OPS_STATE_TOBEFREE);
+ if (prev_state == BPF_STRUCT_OPS_STATE_INUSE) {
+ st_map->st_ops->unreg(&st_map->kvalue.data);
+ if (refcount_dec_and_test(&st_map->kvalue.refcnt))
+ bpf_map_put(map);
+ }
+
+ return 0;
+}
+
+static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
+ struct seq_file *m)
+{
+ void *value;
+ int err;
+
+ value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
+ if (!value)
+ return;
+
+ err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
+ if (!err) {
+ btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
+ value, m);
+ seq_puts(m, "\n");
+ }
+
+ kfree(value);
+}
+
+static void bpf_struct_ops_map_free(struct bpf_map *map)
+{
+ struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+
+ if (st_map->progs)
+ bpf_struct_ops_map_put_progs(st_map);
+ bpf_map_area_free(st_map->progs);
+ bpf_jit_free_exec(st_map->image);
+ bpf_map_area_free(st_map->uvalue);
+ bpf_map_area_free(st_map);
+}
+
+static int bpf_struct_ops_map_alloc_check(union bpf_attr *attr)
+{
+ if (attr->key_size != sizeof(unsigned int) || attr->max_entries != 1 ||
+ attr->map_flags || !attr->btf_vmlinux_value_type_id)
+ return -EINVAL;
+ return 0;
+}
+
+static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
+{
+ const struct bpf_struct_ops *st_ops;
+ size_t map_total_size, st_map_size;
+ struct bpf_struct_ops_map *st_map;
+ const struct btf_type *t, *vt;
+ struct bpf_map_memory mem;
+ struct bpf_map *map;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EPERM);
+
+ st_ops = bpf_struct_ops_find_value(attr->btf_vmlinux_value_type_id);
+ if (!st_ops)
+ return ERR_PTR(-ENOTSUPP);
+
+ vt = st_ops->value_type;
+ if (attr->value_size != vt->size)
+ return ERR_PTR(-EINVAL);
+
+ t = st_ops->type;
+
+ st_map_size = sizeof(*st_map) +
+ /* kvalue stores the
+ * struct bpf_struct_ops_tcp_congestions_ops
+ */
+ (vt->size - sizeof(struct bpf_struct_ops_value));
+ map_total_size = st_map_size +
+ /* uvalue */
+ sizeof(vt->size) +
+ /* struct bpf_progs **progs */
+ btf_type_vlen(t) * sizeof(struct bpf_prog *);
+ err = bpf_map_charge_init(&mem, map_total_size);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE);
+ if (!st_map) {
+ bpf_map_charge_finish(&mem);
+ return ERR_PTR(-ENOMEM);
+ }
+ st_map->st_ops = st_ops;
+ map = &st_map->map;
+
+ st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE);
+ st_map->progs =
+ bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_prog *),
+ NUMA_NO_NODE);
+ st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
+ if (!st_map->uvalue || !st_map->progs || !st_map->image) {
+ bpf_struct_ops_map_free(map);
+ bpf_map_charge_finish(&mem);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ mutex_init(&st_map->lock);
+ set_vm_flush_reset_perms(st_map->image);
+ bpf_map_init_from_attr(map, attr);
+ bpf_map_charge_move(&map->memory, &mem);
+
+ return map;
+}
+
+const struct bpf_map_ops bpf_struct_ops_map_ops = {
+ .map_alloc_check = bpf_struct_ops_map_alloc_check,
+ .map_alloc = bpf_struct_ops_map_alloc,
+ .map_free = bpf_struct_ops_map_free,
+ .map_get_next_key = bpf_struct_ops_map_get_next_key,
+ .map_lookup_elem = bpf_struct_ops_map_lookup_elem,
+ .map_delete_elem = bpf_struct_ops_map_delete_elem,
+ .map_update_elem = bpf_struct_ops_map_update_elem,
+ .map_seq_show_elem = bpf_struct_ops_map_seq_show_elem,
+};
+
+/* "const void *" because some subsystem is
+ * passing a const (e.g. const struct tcp_congestion_ops *)
+ */
+bool bpf_struct_ops_get(const void *kdata)
+{
+ struct bpf_struct_ops_value *kvalue;
+
+ kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
+
+ return refcount_inc_not_zero(&kvalue->refcnt);
+}
+
+void bpf_struct_ops_put(const void *kdata)
+{
+ struct bpf_struct_ops_value *kvalue;
+
+ kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
+ if (refcount_dec_and_test(&kvalue->refcnt)) {
+ struct bpf_struct_ops_map *st_map;
+
+ st_map = container_of(kvalue, struct bpf_struct_ops_map,
+ kvalue);
+ bpf_map_put(&st_map->map);
+ }
+}