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authorYonghong Song <yhs@fb.com>2020-05-09 19:59:06 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-05-10 02:05:26 +0200
commit367ec3e4834cbd611401c2c40a23c22c825474f1 (patch)
tree168079defa34ecb2b4860c765de8639bc001c222 /kernel/bpf
parentbpf: Create anonymous bpf iterator (diff)
downloadlinux-367ec3e4834cbd611401c2c40a23c22c825474f1.tar.xz
linux-367ec3e4834cbd611401c2c40a23c22c825474f1.zip
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/bpf')
-rw-r--r--kernel/bpf/bpf_iter.c17
-rw-r--r--kernel/bpf/inode.c5
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 *