On 4/22/24 10:12, Kui-Feng Lee wrote:
On 4/19/24 17:05, Martin KaFai Lau wrote:
On 4/16/24 5:25 PM, Kui-Feng Lee wrote:
+int bpffs_struct_ops_link_open(struct inode *inode, struct file *filp)
+{
+ struct bpf_struct_ops_link *link = inode->i_private;
+
+ /* Paired with bpf_link_put_direct() in bpf_link_release(). */
+ bpf_link_inc(&link->link);
+ filp->private_data = link;
+ return 0;
+}
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index af5d2ffadd70..b020d761ab0a 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -360,11 +360,16 @@ static int bpf_mkmap(struct dentry *dentry,
umode_t mode, void *arg)
static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg)
{
+ const struct file_operations *fops;
struct bpf_link *link = arg;
- return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops,
- bpf_link_is_iter(link) ?
- &bpf_iter_fops : &bpffs_obj_fops);
+ if (bpf_link_is_iter(link))
+ fops = &bpf_iter_fops;
+ else if (link->type == BPF_LINK_TYPE_STRUCT_OPS)
Open a pinned link and then update should not be specific to
struct_ops link. e.g. should be useful to the cgroup link also?
It could be. Here, I played safe in case it creates any unwanted side
effect for links of unknown types.
By the way, may I put it in a follow up patch if we want cgroup links?
Andrii, wdyt about supporting other link types also?
+ fops = &bpf_link_fops;
+ else
+ fops = &bpffs_obj_fops;
+ return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops, fops);
}
static struct dentry *
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7d392ec83655..f66bc6215faa 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3108,7 +3108,19 @@ static void bpf_link_show_fdinfo(struct
seq_file *m, struct file *filp)
}
#endif
-static const struct file_operations bpf_link_fops = {
+/* Support opening pinned links */
+static int bpf_link_open(struct inode *inode, struct file *filp)
+{
+ struct bpf_link *link = inode->i_private;
+
+ if (link->type == BPF_LINK_TYPE_STRUCT_OPS)
+ return bpffs_struct_ops_link_open(inode, filp);
+
+ return -EOPNOTSUPP;
+}
+
+const struct file_operations bpf_link_fops = {
+ .open = bpf_link_open,
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_link_show_fdinfo,
#endif
