diff options
author | Kui-Feng Lee <[email protected]> | 2023-03-22 20:24:02 -0700 |
---|---|---|
committer | Martin KaFai Lau <[email protected]> | 2023-03-22 22:53:02 -0700 |
commit | aef56f2e918bf8fc8de25f0b36e8c2aba44116ec (patch) | |
tree | 38d252f9d4fa8ef28ccf18e642bb3741d658fb92 /kernel/bpf/syscall.c | |
parent | 8d1608d70927747da9c1a8770edf7b6ee68f8ebc (diff) |
bpf: Update the struct_ops of a bpf_link.
By improving the BPF_LINK_UPDATE command of bpf(), it should allow you
to conveniently switch between different struct_ops on a single
bpf_link. This would enable smoother transitions from one struct_ops
to another.
The struct_ops maps passing along with BPF_LINK_UPDATE should have the
BPF_F_LINK flag.
Signed-off-by: Kui-Feng Lee <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>
Diffstat (limited to 'kernel/bpf/syscall.c')
-rw-r--r-- | kernel/bpf/syscall.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 21f76698875c..b4d758fa5981 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4682,6 +4682,35 @@ out: return ret; } +static int link_update_map(struct bpf_link *link, union bpf_attr *attr) +{ + struct bpf_map *new_map, *old_map = NULL; + int ret; + + new_map = bpf_map_get(attr->link_update.new_map_fd); + if (IS_ERR(new_map)) + return -EINVAL; + + if (attr->link_update.flags & BPF_F_REPLACE) { + old_map = bpf_map_get(attr->link_update.old_map_fd); + if (IS_ERR(old_map)) { + ret = -EINVAL; + goto out_put; + } + } else if (attr->link_update.old_map_fd) { + ret = -EINVAL; + goto out_put; + } + + ret = link->ops->update_map(link, new_map, old_map); + + if (old_map) + bpf_map_put(old_map); +out_put: + bpf_map_put(new_map); + return ret; +} + #define BPF_LINK_UPDATE_LAST_FIELD link_update.old_prog_fd static int link_update(union bpf_attr *attr) @@ -4702,6 +4731,11 @@ static int link_update(union bpf_attr *attr) if (IS_ERR(link)) return PTR_ERR(link); + if (link->ops->update_map) { + ret = link_update_map(link, attr); + goto out_put_link; + } + new_prog = bpf_prog_get(attr->link_update.new_prog_fd); if (IS_ERR(new_prog)) { ret = PTR_ERR(new_prog); |