diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 3975969719de..7c75a1813321 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -269,7 +269,7 @@ static void xdr_decode_AFSCallBack(struct afs_call *call,
 
 	write_seqlock(&vnode->cb_lock);
 
-	if (call->cb_break == afs_cb_break_sum(vnode, cbi)) {
+	if (!afs_cb_is_broken(call->cb_break, vnode, cbi)) {
 		vnode->cb_version	= ntohl(*bp++);
 		cb_expiry		= ntohl(*bp++);
 		vnode->cb_type		= ntohl(*bp++);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e5b596bd8acf..b60d15212975 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -776,10 +776,13 @@ static inline unsigned int afs_calc_vnode_cb_break(struct afs_vnode *vnode)
 	return vnode->cb_break + vnode->cb_s_break + vnode->cb_v_break;
 }
 
-static inline unsigned int afs_cb_break_sum(struct afs_vnode *vnode,
-					    struct afs_cb_interest *cbi)
+static inline bool afs_cb_is_broken(unsigned int cb_break,
+				    const struct afs_vnode *vnode,
+				    const struct afs_cb_interest *cbi)
 {
-	return vnode->cb_break + cbi->server->cb_s_break + vnode->volume->cb_v_break;
+	return !cbi || cb_break != (vnode->cb_break +
+				    cbi->server->cb_s_break +
+				    vnode->volume->cb_v_break);
 }
 
 /*
diff --git a/fs/afs/security.c b/fs/afs/security.c
index d1ae53fd3739..5f58a9a17e69 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -147,7 +147,8 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key,
 					break;
 				}
 
-				if (cb_break != afs_cb_break_sum(vnode, vnode->cb_interest)) {
+				if (afs_cb_is_broken(cb_break, vnode,
+						     vnode->cb_interest)) {
 					changed = true;
 					break;
 				}
@@ -177,7 +178,7 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key,
 		}
 	}
 
-	if (cb_break != afs_cb_break_sum(vnode, vnode->cb_interest))
+	if (afs_cb_is_broken(cb_break, vnode, vnode->cb_interest))
 		goto someone_else_changed_it;
 
 	/* We need a ref on any permits list we want to copy as we'll have to
@@ -256,7 +257,7 @@ found:
 
 	spin_lock(&vnode->lock);
 	zap = rcu_access_pointer(vnode->permit_cache);
-	if (cb_break == afs_cb_break_sum(vnode, vnode->cb_interest) &&
+	if (!afs_cb_is_broken(cb_break, vnode, vnode->cb_interest) &&
 	    zap == permits)
 		rcu_assign_pointer(vnode->permit_cache, replacement);
 	else
diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c
index d5e3f0095040..12658c1363ae 100644
--- a/fs/afs/yfsclient.c
+++ b/fs/afs/yfsclient.c
@@ -324,7 +324,7 @@ static void xdr_decode_YFSCallBack(struct afs_call *call,
 
 	write_seqlock(&vnode->cb_lock);
 
-	if (call->cb_break == afs_cb_break_sum(vnode, cbi)) {
+	if (!afs_cb_is_broken(call->cb_break, vnode, cbi)) {
 		cb_expiry = xdr_to_u64(xdr->expiration_time);
 		do_div(cb_expiry, 10 * 1000 * 1000);
 		vnode->cb_version	= ntohl(xdr->version);