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authorAndrii Nakryiko <andriin@fb.com>2020-04-28 17:16:05 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-04-28 17:27:07 -0700
commitf9d041271cf44ca02eed0cc82e1a6d8c814c53ed (patch)
treea248c1de80b38d6ab048574215a164431ce8ea83 /kernel/bpf/cgroup.c
parent9b329d0dbe413bf46eb5010edd06b3076960a60a (diff)
bpf: Refactor bpf_link update handling
Make bpf_link update support more generic by making it into another bpf_link_ops methods. This allows generic syscall handling code to be agnostic to various conditionally compiled features (e.g., the case of CONFIG_CGROUP_BPF). This also allows to keep link type-specific code to remain static within respective code base. Refactor existing bpf_cgroup_link code and take advantage of this. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200429001614.1544-2-andriin@fb.com
Diffstat (limited to 'kernel/bpf/cgroup.c')
-rw-r--r--kernel/bpf/cgroup.c30
1 files changed, 28 insertions, 2 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index bf634959885c..da6e48e802b2 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -557,8 +557,9 @@ found:
*
* Must be called with cgroup_mutex held.
*/
-int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link,
- struct bpf_prog *new_prog)
+static int __cgroup_bpf_replace(struct cgroup *cgrp,
+ struct bpf_cgroup_link *link,
+ struct bpf_prog *new_prog)
{
struct list_head *progs = &cgrp->bpf.progs[link->type];
struct bpf_prog *old_prog;
@@ -583,6 +584,30 @@ int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link,
return 0;
}
+static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
+ struct bpf_prog *old_prog)
+{
+ struct bpf_cgroup_link *cg_link;
+ int ret;
+
+ cg_link = container_of(link, struct bpf_cgroup_link, link);
+
+ mutex_lock(&cgroup_mutex);
+ /* link might have been auto-released by dying cgroup, so fail */
+ if (!cg_link->cgroup) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ if (old_prog && link->prog != old_prog) {
+ ret = -EPERM;
+ goto out_unlock;
+ }
+ ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog);
+out_unlock:
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
+
static struct bpf_prog_list *find_detach_entry(struct list_head *progs,
struct bpf_prog *prog,
struct bpf_cgroup_link *link,
@@ -811,6 +836,7 @@ static void bpf_cgroup_link_dealloc(struct bpf_link *link)
const struct bpf_link_ops bpf_cgroup_link_lops = {
.release = bpf_cgroup_link_release,
.dealloc = bpf_cgroup_link_dealloc,
+ .update_prog = cgroup_bpf_replace,
};
int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)