diff options
| -rw-r--r-- | include/linux/bpf.h | 11 | ||||
| -rw-r--r-- | kernel/bpf/bpf_iter.c | 85 |
2 files changed, 91 insertions, 5 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index b06653ab3476..ffe0b9b669bf 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1129,6 +1129,9 @@ int bpf_obj_pin_user(u32 ufd, const char __user *pathname); int bpf_obj_get_user(const char __user *pathname, int flags); #define BPF_ITER_FUNC_PREFIX "__bpf_iter__" +#define DEFINE_BPF_ITER_FUNC(target, args...) \ + extern int __bpf_iter__ ## target(args); \ + int __init __bpf_iter__ ## target(args) { return 0; } typedef int (*bpf_iter_init_seq_priv_t)(void *private_data); typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data); @@ -1141,12 +1144,20 @@ struct bpf_iter_reg { u32 seq_priv_size; }; +struct bpf_iter_meta { + __bpf_md_ptr(struct seq_file *, seq); + u64 session_id; + u64 seq_num; +}; + int bpf_iter_reg_target(struct bpf_iter_reg *reg_info); void bpf_iter_unreg_target(const char *target); bool bpf_iter_prog_supported(struct bpf_prog *prog); int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); int bpf_iter_new_fd(struct bpf_link *link); bool bpf_link_is_iter(struct bpf_link *link); +struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop); +int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx); int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 090f09b0eacb..30efd15cd4a0 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -41,6 +41,33 @@ static atomic64_t session_id; static int prepare_seq_file(struct file *file, struct bpf_iter_link *link); +static void bpf_iter_inc_seq_num(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv = container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->seq_num++; +} + +static void bpf_iter_dec_seq_num(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv = container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->seq_num--; +} + +static void bpf_iter_done_stop(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv = container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->done_stop = true; +} + /* bpf_seq_read, a customized and simpler version for bpf iterator. * no_llseek is assumed for this file. * The following are differences from seq_read(): @@ -93,6 +120,10 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, err = seq->op->show(seq, p); if (err > 0) { + /* object is skipped, decrease seq_num, so next + * valid object can reuse the same seq_num. + */ + bpf_iter_dec_seq_num(seq); seq->count = 0; } else if (err < 0 || seq_has_overflowed(seq)) { if (!err) @@ -117,11 +148,15 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, if (IS_ERR_OR_NULL(p)) break; + /* got a valid next object, increase seq_num */ + bpf_iter_inc_seq_num(seq); + if (seq->count >= size) break; err = seq->op->show(seq, p); if (err > 0) { + bpf_iter_dec_seq_num(seq); seq->count = offs; } else if (err < 0 || seq_has_overflowed(seq)) { seq->count = offs; @@ -138,11 +173,15 @@ stop: offs = seq->count; /* bpf program called if !p */ seq->op->stop(seq, p); - if (!p && seq_has_overflowed(seq)) { - seq->count = offs; - if (offs == 0) { - err = -E2BIG; - goto done; + if (!p) { + if (!seq_has_overflowed(seq)) { + bpf_iter_done_stop(seq); + } else { + seq->count = offs; + if (offs == 0) { + err = -E2BIG; + goto done; + } } } @@ -453,3 +492,39 @@ free_fd: put_unused_fd(fd); return err; } + +struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop) +{ + struct bpf_iter_priv_data *iter_priv; + struct seq_file *seq; + void *seq_priv; + + seq = meta->seq; + if (seq->file->f_op != &bpf_iter_fops) + return NULL; + + seq_priv = seq->private; + iter_priv = container_of(seq_priv, struct bpf_iter_priv_data, + target_private); + + if (in_stop && iter_priv->done_stop) + return NULL; + + meta->session_id = iter_priv->session_id; + meta->seq_num = iter_priv->seq_num; + + return iter_priv->prog; +} + +int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx) +{ + int ret; + + rcu_read_lock(); + migrate_disable(); + ret = BPF_PROG_RUN(prog, ctx); + migrate_enable(); + rcu_read_unlock(); + + return ret == 0 ? 0 : -EAGAIN; +} |