Introduce the struct bpf_tramp_multi_link, which is used to attach a bpf_link to multi trampoline. Meanwhile, introduce corresponding function bpf_trampoline_multi_{link,unlink}_prog.
Signed-off-by: Menglong Dong dongmenglong.8@bytedance.com --- include/linux/bpf.h | 14 ++++++++++++ kernel/bpf/trampoline.c | 47 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 61 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2b5cd6100fc4..4e8f17d9f022 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -57,6 +57,7 @@ struct user_namespace; struct super_block; struct inode; struct bpf_tramp_link; +struct bpf_tramp_multi_link;
extern struct idr btf_idr; extern spinlock_t btf_idr_lock; @@ -1282,6 +1283,8 @@ struct bpf_trampoline *bpf_trampoline_get(u64 key, struct bpf_attach_target_info *tgt_info); void bpf_trampoline_put(struct bpf_trampoline *tr); int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs); +int bpf_trampoline_multi_link_prog(struct bpf_tramp_multi_link *link); +int bpf_trampoline_multi_unlink_prog(struct bpf_tramp_multi_link *link);
/* * When the architecture supports STATIC_CALL replace the bpf_dispatcher_fn @@ -1614,6 +1617,17 @@ struct bpf_shim_tramp_link { struct bpf_trampoline *trampoline; };
+struct bpf_tramp_multi_link_entry { + struct bpf_trampoline *trampoline; + struct bpf_tramp_link_conn conn; +}; + +struct bpf_tramp_multi_link { + struct bpf_link link; + u32 cnt; + struct bpf_tramp_multi_link_entry *entries; +}; + struct bpf_tracing_link { struct bpf_tramp_link link; enum bpf_attach_type attach_type; diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index cf9b84f785f3..2167aa3fe583 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -607,6 +607,53 @@ int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampolin return err; }
+static int __bpf_trampoline_multi_unlink_prog(struct bpf_tramp_multi_link *link, + u32 cnt) +{ + struct bpf_tramp_multi_link_entry *entry; + struct bpf_trampoline *tr; + int err = 0, i; + + for (i = 0; i < cnt; i++) { + entry = &link->entries[i]; + tr = entry->trampoline; + mutex_lock(&tr->mutex); + err = __bpf_trampoline_unlink_prog(&entry->conn, + entry->trampoline); + mutex_unlock(&tr->mutex); + if (err) + break; + } + return err; +} + +int bpf_trampoline_multi_unlink_prog(struct bpf_tramp_multi_link *link) +{ + return __bpf_trampoline_multi_unlink_prog(link, link->cnt); +} + +int bpf_trampoline_multi_link_prog(struct bpf_tramp_multi_link *link) +{ + struct bpf_tramp_multi_link_entry *entry; + struct bpf_trampoline *tr; + int err = 0, i; + + for (i = 0; i < link->cnt; i++) { + entry = &link->entries[i]; + tr = entry->trampoline; + mutex_lock(&tr->mutex); + err = __bpf_trampoline_link_prog(&entry->conn, tr); + mutex_unlock(&tr->mutex); + if (err) + goto unlink; + } + + return 0; +unlink: + __bpf_trampoline_multi_unlink_prog(link, i); + return err; +} + #if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM) static void bpf_shim_tramp_link_release(struct bpf_link *link) {