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[net-next,1/3] bpf, maps: add release callback

Message ID 214337ce2c843119386fdc194d4ba10c7093cac9.1466021686.git.daniel@iogearbox.net
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Daniel Borkmann June 15, 2016, 8:47 p.m. UTC 
Add a release callback for maps that is invoked when the last
reference to its struct file is gone and the struct file about
to be released by vfs. The handler will be used by fd array maps.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
 include/linux/bpf.h  | 3 ++-
 kernel/bpf/syscall.c | 7 ++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1bcae82..29b5a1a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -19,7 +19,8 @@  struct bpf_map;
 struct bpf_map_ops {
 	/* funcs callable from userspace (via syscall) */
 	struct bpf_map *(*map_alloc)(union bpf_attr *attr);
-	void (*map_free)(struct bpf_map *);
+	void (*map_release)(struct bpf_map *map, struct file *map_file);
+	void (*map_free)(struct bpf_map *map);
 	int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
 
 	/* funcs callable from userspace and from eBPF programs */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 46ecce4..fc3adcd 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -124,7 +124,12 @@  void bpf_map_put_with_uref(struct bpf_map *map)
 
 static int bpf_map_release(struct inode *inode, struct file *filp)
 {
-	bpf_map_put_with_uref(filp->private_data);
+	struct bpf_map *map = filp->private_data;
+
+	if (map->ops->map_release)
+		map->ops->map_release(map, filp);
+
+	bpf_map_put_with_uref(map);
 	return 0;
 }