bpf, cgroups: clean up kerneldoc warnings

Building with W=1 reveals some bitrot:

  CC      kernel/bpf/cgroup.o
kernel/bpf/cgroup.c:238: warning: Function parameter or member 'flags' not described in '__cgroup_bpf_attach'
kernel/bpf/cgroup.c:367: warning: Function parameter or member 'unused_flags' not described in '__cgroup_bpf_detach'

Add a kerneldoc line for 'flags'.

Fixing the warning for 'unused_flags' is best approached by
removing the unused parameter on the function call.
Signed-off-by: NValdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

include/linux/bpf-cgroup.h

@@ -78,7 +78,7 @@ int cgroup_bpf_inherit(struct cgroup *cgrp);
 int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
 			enum bpf_attach_type type, u32 flags);
 int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
-			enum bpf_attach_type type, u32 flags);
+			enum bpf_attach_type type);
 int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
 		       union bpf_attr __user *uattr);
 

kernel/bpf/cgroup.c

@@ -230,6 +230,7 @@ static int update_effective_progs(struct cgroup *cgrp,
  * @cgrp: The cgroup which descendants to traverse
  * @prog: A program to attach
  * @type: Type of attach operation
+ * @flags: Option flags
  *
  * Must be called with cgroup_mutex held.
  */
@@ -363,7 +364,7 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
  * Must be called with cgroup_mutex held.
  */
 int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
-			enum bpf_attach_type type, u32 unused_flags)
+			enum bpf_attach_type type)
 {
 	struct list_head *progs = &cgrp->bpf.progs[type];
 	enum bpf_cgroup_storage_type stype;

kernel/cgroup/cgroup.c

@@ -5996,7 +5996,7 @@ int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
 	int ret;
 
 	mutex_lock(&cgroup_mutex);
-	ret = __cgroup_bpf_detach(cgrp, prog, type, flags);
+	ret = __cgroup_bpf_detach(cgrp, prog, type);
 	mutex_unlock(&cgroup_mutex);
 	return ret;
 }