diff options
| author | Yonghong Song <yhs@fb.com> | 2020-05-09 10:59:06 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-05-09 17:05:26 -0700 |
| commit | 367ec3e4834cbd611401c2c40a23c22c825474f1 (patch) | |
| tree | 168079defa34ecb2b4860c765de8639bc001c222 /kernel | |
| parent | ac51d99bf81caac8d8881fe52098948110d0de68 (diff) | |
| download | linux-367ec3e4834cbd611401c2c40a23c22c825474f1.tar.gz | |
bpf: Create file bpf iterator
To produce a file bpf iterator, the fd must be corresponding to a link_fd assocciated with a trace/iter program. When the pinned file is opened, a seq_file will be generated. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200509175906.2475893-1-yhs@fb.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/bpf_iter.c | 17 | ||||
| -rw-r--r-- | kernel/bpf/inode.c | 5 |
2 files changed, 20 insertions, 2 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index e7129b57865f..090f09b0eacb 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -39,6 +39,8 @@ static DEFINE_MUTEX(link_mutex); /* incremented on every opened seq_file */ static atomic64_t session_id; +static int prepare_seq_file(struct file *file, struct bpf_iter_link *link); + /* 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(): @@ -162,6 +164,13 @@ done: return copied; } +static int iter_open(struct inode *inode, struct file *file) +{ + struct bpf_iter_link *link = inode->i_private; + + return prepare_seq_file(file, link); +} + static int iter_release(struct inode *inode, struct file *file) { struct bpf_iter_priv_data *iter_priv; @@ -183,7 +192,8 @@ static int iter_release(struct inode *inode, struct file *file) return seq_release_private(inode, file); } -static const struct file_operations bpf_iter_fops = { +const struct file_operations bpf_iter_fops = { + .open = iter_open, .llseek = no_llseek, .read = bpf_seq_read, .release = iter_release, @@ -310,6 +320,11 @@ static const struct bpf_link_ops bpf_iter_link_lops = { .update_prog = bpf_iter_link_replace, }; +bool bpf_link_is_iter(struct bpf_link *link) +{ + return link->ops == &bpf_iter_link_lops; +} + int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct bpf_link_primer link_primer; diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 95087d9f4ed3..fb878ba3f22f 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -358,8 +358,11 @@ static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg) static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg) { + struct bpf_link *link = arg; + return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops, - &bpffs_obj_fops); + bpf_link_is_iter(link) ? + &bpf_iter_fops : &bpffs_obj_fops); } static struct dentry * |