flags);
}
- /* must increment bpf_prog_active to avoid kprobe+bpf triggering from
- * inside bpf map update or delete otherwise deadlocks are possible
- */
- preempt_disable();
- __this_cpu_inc(bpf_prog_active);
+ bpf_disable_instrumentation();
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
err = bpf_percpu_hash_update(map, key, value, flags);
err = map->ops->map_update_elem(map, key, value, flags);
rcu_read_unlock();
}
- __this_cpu_dec(bpf_prog_active);
- preempt_enable();
+ bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
return err;
if (bpf_map_is_dev_bound(map))
return bpf_map_offload_lookup_elem(map, key, value);
- preempt_disable();
- this_cpu_inc(bpf_prog_active);
+ bpf_disable_instrumentation();
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
err = bpf_percpu_hash_copy(map, key, value);
rcu_read_unlock();
}
- this_cpu_dec(bpf_prog_active);
- preempt_enable();
+ bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
return err;
}
EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);
+struct bpf_map *bpf_map_get(u32 ufd)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_map *map;
+
+ map = __bpf_map_get(f);
+ if (IS_ERR(map))
+ return map;
+
+ bpf_map_inc(map);
+ fdput(f);
+
+ return map;
+}
+
struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
struct fd f = fdget(ufd);
goto out;
}
- preempt_disable();
- __this_cpu_inc(bpf_prog_active);
+ bpf_disable_instrumentation();
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
- __this_cpu_dec(bpf_prog_active);
- preempt_enable();
+ bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
out:
kfree(key);
break;
}
- preempt_disable();
- __this_cpu_inc(bpf_prog_active);
+ bpf_disable_instrumentation();
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
- __this_cpu_dec(bpf_prog_active);
- preempt_enable();
+ bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
if (err)
break;
attr->file_flags);
}
-static int bpf_tracing_prog_release(struct inode *inode, struct file *filp)
+struct bpf_link {
+ atomic64_t refcnt;
+ const struct bpf_link_ops *ops;
+ struct bpf_prog *prog;
+ struct work_struct work;
+};
+
+void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops,
+ struct bpf_prog *prog)
+{
+ atomic64_set(&link->refcnt, 1);
+ link->ops = ops;
+ link->prog = prog;
+}
+
+/* Clean up bpf_link and corresponding anon_inode file and FD. After
+ * anon_inode is created, bpf_link can't be just kfree()'d due to deferred
+ * anon_inode's release() call. This helper manages marking bpf_link as
+ * defunct, releases anon_inode file and puts reserved FD.
+ */
+static void bpf_link_cleanup(struct bpf_link *link, struct file *link_file,
+ int link_fd)
{
- struct bpf_prog *prog = filp->private_data;
+ link->prog = NULL;
+ fput(link_file);
+ put_unused_fd(link_fd);
+}
- WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog));
- bpf_prog_put(prog);
+void bpf_link_inc(struct bpf_link *link)
+{
+ atomic64_inc(&link->refcnt);
+}
+
+/* bpf_link_free is guaranteed to be called from process context */
+static void bpf_link_free(struct bpf_link *link)
+{
+ if (link->prog) {
+ /* detach BPF program, clean up used resources */
+ link->ops->release(link);
+ bpf_prog_put(link->prog);
+ }
+ /* free bpf_link and its containing memory */
+ link->ops->dealloc(link);
+}
+
+static void bpf_link_put_deferred(struct work_struct *work)
+{
+ struct bpf_link *link = container_of(work, struct bpf_link, work);
+
+ bpf_link_free(link);
+}
+
+/* bpf_link_put can be called from atomic context, but ensures that resources
+ * are freed from process context
+ */
+void bpf_link_put(struct bpf_link *link)
+{
+ if (!atomic64_dec_and_test(&link->refcnt))
+ return;
+
+ if (in_atomic()) {
+ INIT_WORK(&link->work, bpf_link_put_deferred);
+ schedule_work(&link->work);
+ } else {
+ bpf_link_free(link);
+ }
+}
+
+static int bpf_link_release(struct inode *inode, struct file *filp)
+{
+ struct bpf_link *link = filp->private_data;
+
+ bpf_link_put(link);
return 0;
}
-static const struct file_operations bpf_tracing_prog_fops = {
- .release = bpf_tracing_prog_release,
+#ifdef CONFIG_PROC_FS
+static const struct bpf_link_ops bpf_raw_tp_lops;
+static const struct bpf_link_ops bpf_tracing_link_lops;
+static const struct bpf_link_ops bpf_xdp_link_lops;
+
+static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+ const struct bpf_link *link = filp->private_data;
+ const struct bpf_prog *prog = link->prog;
+ char prog_tag[sizeof(prog->tag) * 2 + 1] = { };
+ const char *link_type;
+
+ if (link->ops == &bpf_raw_tp_lops)
+ link_type = "raw_tracepoint";
+ else if (link->ops == &bpf_tracing_link_lops)
+ link_type = "tracing";
+ else
+ link_type = "unknown";
+
+ bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
+ seq_printf(m,
+ "link_type:\t%s\n"
+ "prog_tag:\t%s\n"
+ "prog_id:\t%u\n",
+ link_type,
+ prog_tag,
+ prog->aux->id);
+}
+#endif
+
+const struct file_operations bpf_link_fops = {
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = bpf_link_show_fdinfo,
+#endif
+ .release = bpf_link_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
+int bpf_link_new_fd(struct bpf_link *link)
+{
+ return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC);
+}
+
+/* Similar to bpf_link_new_fd, create anon_inode for given bpf_link, but
+ * instead of immediately installing fd in fdtable, just reserve it and
+ * return. Caller then need to either install it with fd_install(fd, file) or
+ * release with put_unused_fd(fd).
+ * This is useful for cases when bpf_link attachment/detachment are
+ * complicated and expensive operations and should be delayed until all the fd
+ * reservation and anon_inode creation succeeds.
+ */
+struct file *bpf_link_new_file(struct bpf_link *link, int *reserved_fd)
+{
+ struct file *file;
+ int fd;
+
+ fd = get_unused_fd_flags(O_CLOEXEC);
+ if (fd < 0)
+ return ERR_PTR(fd);
+
+ file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC);
+ if (IS_ERR(file)) {
+ put_unused_fd(fd);
+ return file;
+ }
+
+ *reserved_fd = fd;
+ return file;
+}
+
+struct bpf_link *bpf_link_get_from_fd(u32 ufd)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_link *link;
+
+ if (!f.file)
+ return ERR_PTR(-EBADF);
+ if (f.file->f_op != &bpf_link_fops) {
+ fdput(f);
+ return ERR_PTR(-EINVAL);
+ }
+
+ link = f.file->private_data;
+ bpf_link_inc(link);
+ fdput(f);
+
+ return link;
+}
+
+struct bpf_tracing_link {
+ struct bpf_link link;
+};
+
+static void bpf_tracing_link_release(struct bpf_link *link)
+{
+ WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog));
+}
+
+static void bpf_tracing_link_dealloc(struct bpf_link *link)
+{
+ struct bpf_tracing_link *tr_link =
+ container_of(link, struct bpf_tracing_link, link);
+
+ kfree(tr_link);
+}
+
+static const struct bpf_link_ops bpf_tracing_link_lops = {
+ .release = bpf_tracing_link_release,
+ .dealloc = bpf_tracing_link_dealloc,
+};
+
static int bpf_tracing_prog_attach(struct bpf_prog *prog)
{
- int tr_fd, err;
+ struct bpf_tracing_link *link;
+ struct file *link_file;
+ int link_fd, err;
if (prog->expected_attach_type != BPF_TRACE_FENTRY &&
prog->expected_attach_type != BPF_TRACE_FEXIT &&
+ prog->expected_attach_type != BPF_MODIFY_RETURN &&
prog->type != BPF_PROG_TYPE_EXT) {
err = -EINVAL;
goto out_put_prog;
}
- err = bpf_trampoline_link_prog(prog);
- if (err)
+ link = kzalloc(sizeof(*link), GFP_USER);
+ if (!link) {
+ err = -ENOMEM;
+ goto out_put_prog;
+ }
+ bpf_link_init(&link->link, &bpf_tracing_link_lops, prog);
+
+ link_file = bpf_link_new_file(&link->link, &link_fd);
+ if (IS_ERR(link_file)) {
+ kfree(link);
+ err = PTR_ERR(link_file);
goto out_put_prog;
+ }
- tr_fd = anon_inode_getfd("bpf-tracing-prog", &bpf_tracing_prog_fops,
- prog, O_CLOEXEC);
- if (tr_fd < 0) {
- WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog));
- err = tr_fd;
+ err = bpf_trampoline_link_prog(prog);
+ if (err) {
+ bpf_link_cleanup(&link->link, link_file, link_fd);
goto out_put_prog;
}
- return tr_fd;
+
+ fd_install(link_fd, link_file);
+ return link_fd;
out_put_prog:
bpf_prog_put(prog);
return err;
}
-struct bpf_raw_tracepoint {
+struct bpf_raw_tp_link {
+ struct bpf_link link;
struct bpf_raw_event_map *btp;
- struct bpf_prog *prog;
};
-static int bpf_raw_tracepoint_release(struct inode *inode, struct file *filp)
+static void bpf_raw_tp_link_release(struct bpf_link *link)
{
- struct bpf_raw_tracepoint *raw_tp = filp->private_data;
+ struct bpf_raw_tp_link *raw_tp =
+ container_of(link, struct bpf_raw_tp_link, link);
- if (raw_tp->prog) {
- bpf_probe_unregister(raw_tp->btp, raw_tp->prog);
- bpf_prog_put(raw_tp->prog);
- }
+ bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog);
bpf_put_raw_tracepoint(raw_tp->btp);
+}
+
+static void bpf_raw_tp_link_dealloc(struct bpf_link *link)
+{
+ struct bpf_raw_tp_link *raw_tp =
+ container_of(link, struct bpf_raw_tp_link, link);
+
kfree(raw_tp);
- return 0;
}
-static const struct file_operations bpf_raw_tp_fops = {
- .release = bpf_raw_tracepoint_release,
- .read = bpf_dummy_read,
- .write = bpf_dummy_write,
+static const struct bpf_link_ops bpf_raw_tp_lops = {
+ .release = bpf_raw_tp_link_release,
+ .dealloc = bpf_raw_tp_link_dealloc,
};
#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
{
- struct bpf_raw_tracepoint *raw_tp;
+ struct bpf_raw_tp_link *link;
struct bpf_raw_event_map *btp;
+ struct file *link_file;
struct bpf_prog *prog;
const char *tp_name;
char buf[128];
- int tp_fd, err;
+ int link_fd, err;
if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
return -EINVAL;
goto out_put_prog;
}
- raw_tp = kzalloc(sizeof(*raw_tp), GFP_USER);
- if (!raw_tp) {
+ link = kzalloc(sizeof(*link), GFP_USER);
+ if (!link) {
err = -ENOMEM;
goto out_put_btp;
}
- raw_tp->btp = btp;
- raw_tp->prog = prog;
+ bpf_link_init(&link->link, &bpf_raw_tp_lops, prog);
+ link->btp = btp;
- err = bpf_probe_register(raw_tp->btp, prog);
- if (err)
- goto out_free_tp;
+ link_file = bpf_link_new_file(&link->link, &link_fd);
+ if (IS_ERR(link_file)) {
+ kfree(link);
+ err = PTR_ERR(link_file);
+ goto out_put_btp;
+ }
- tp_fd = anon_inode_getfd("bpf-raw-tracepoint", &bpf_raw_tp_fops, raw_tp,
- O_CLOEXEC);
- if (tp_fd < 0) {
- bpf_probe_unregister(raw_tp->btp, prog);
- err = tp_fd;
- goto out_free_tp;
+ err = bpf_probe_register(link->btp, prog);
+ if (err) {
+ bpf_link_cleanup(&link->link, link_file, link_fd);
+ goto out_put_btp;
}
- return tp_fd;
-out_free_tp:
- kfree(raw_tp);
+ fd_install(link_fd, link_file);
+ return link_fd;
+
out_put_btp:
bpf_put_raw_tracepoint(btp);
out_put_prog:
if (err)
goto out;
- if (file->f_op == &bpf_raw_tp_fops) {
- struct bpf_raw_tracepoint *raw_tp = file->private_data;
- struct bpf_raw_event_map *btp = raw_tp->btp;
+ if (file->f_op == &bpf_link_fops) {
+ struct bpf_link *link = file->private_data;
- err = bpf_task_fd_query_copy(attr, uattr,
- raw_tp->prog->aux->id,
- BPF_FD_TYPE_RAW_TRACEPOINT,
- btp->tp->name, 0, 0);
- goto put_file;
+ if (link->ops == &bpf_raw_tp_lops) {
+ struct bpf_raw_tp_link *raw_tp =
+ container_of(link, struct bpf_raw_tp_link, link);
+ struct bpf_raw_event_map *btp = raw_tp->btp;
+
+ err = bpf_task_fd_query_copy(attr, uattr,
+ raw_tp->link.prog->aux->id,
+ BPF_FD_TYPE_RAW_TRACEPOINT,
+ btp->tp->name, 0, 0);
+ goto put_file;
+ }
+ goto out_not_supp;
}
event = perf_get_event(file);
goto put_file;
}
+out_not_supp:
err = -ENOTSUPP;
put_file:
fput(file);
projects / linux-2.6-microblaze.git / blobdiff