Hi Jakub, many thanks for your review. Please see my responses inline:
On Tue, 10 Nov 2020 14:56:55 -0800 Jakub Kicinski kuba@kernel.org wrote:
On Sat, 7 Nov 2020 16:31:37 +0100 Andrea Mayer wrote:
We introduce two callbacks used for customizing the creation/destruction of a SRv6 behavior. Such callbacks are defined in the new struct seg6_local_lwtunnel_ops and hereafter we provide a brief description of them:
build_state(...): used for calling the custom constructor of the behavior during its initialization phase and after all the attributes have been parsed successfully;
destroy_state(...): used for calling the custom destructor of the behavior before it is completely destroyed.
Signed-off-by: Andrea Mayer andrea.mayer@uniroma2.it
Looks good, minor nits.
diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c index 63a82e2fdea9..4b0f155d641d 100644 --- a/net/ipv6/seg6_local.c +++ b/net/ipv6/seg6_local.c @@ -33,11 +33,23 @@ struct seg6_local_lwt; +typedef int (*slwt_build_state_t)(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack);+typedef void (*slwt_destroy_state_t)(struct seg6_local_lwt *slwt);
Let's avoid the typedefs. Instead of taking a pointer to the op take a pointer to the ops struct in seg6_local_lwtunnel_build_state() etc.
Ok, I will do it this way in v3.
+/* callbacks used for customizing the creation and destruction of a behavior */ +struct seg6_local_lwtunnel_ops {
- slwt_build_state_t build_state;
- slwt_destroy_state_t destroy_state;
+};
struct seg6_action_desc { int action; unsigned long attrs; int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt); int static_headroom;
- struct seg6_local_lwtunnel_ops slwt_ops;
}; struct bpf_lwt_prog { @@ -1015,6 +1027,45 @@ static void destroy_attrs(struct seg6_local_lwt *slwt) __destroy_attrs(attrs, 0, SEG6_LOCAL_MAX + 1, slwt); } +/* call the custom constructor of the behavior during its initialization phase
- and after that all its attributes have been parsed successfully.
- */
+static int +seg6_local_lwtunnel_build_state(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack)+{
- slwt_build_state_t build_func;
- struct seg6_action_desc *desc;
- int err = 0;
- desc = slwt->desc;
- if (!desc)
return -EINVAL;This is impossible, right?
Yes, it is. I will remove this check in v3.
- build_func = desc->slwt_ops.build_state;
- if (build_func)
err = build_func(slwt, cfg, extack);- return err;
no need for err, just use return directly.
if (!ops->build_state) return 0; return ops->build_state(...);
Ok, I will do it in this way in v3.
+}
+/* call the custom destructor of the behavior which is invoked before the
- tunnel is going to be destroyed.
- */
+static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt) +{
- slwt_destroy_state_t destroy_func;
- struct seg6_action_desc *desc;
- desc = slwt->desc;
- if (!desc)
return;- destroy_func = desc->slwt_ops.destroy_state;
- if (destroy_func)
destroy_func(slwt);+}
static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt) { struct seg6_action_param *param; @@ -1090,8 +1141,16 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla, err = parse_nla_action(tb, slwt); if (err < 0)
/* In case of error, the parse_nla_action() takes care of* releasing resources which have been acquired during the* processing of attributes.*/that's the normal behavior for a kernel function, comment is unnecessary IMO
Yes and this is the way it should be. But before this patch, the parse_nla_action() in case of error did not always release all the acquired resources. From this patcheset onward, the parse_nla_action() behaves like we expect. Therefore, I will remove the comment in v3.
goto out_free;
- err = seg6_local_lwtunnel_build_state(slwt, cfg, extack);
- if (err < 0)
goto free_attrs;The function is called destroy_attrs, call the label out_destroy_attrs, or err_destroy_attrs.
Fine, I will stick with the out_destroy_attrs to be consistent and uniform with the out_free label in v3.
newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL; newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT; newts->headroom = slwt->headroom; @@ -1100,6 +1159,9 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla, return 0; +free_attrs:
- destroy_attrs(slwt);
no need for empty lines on error paths
Ok.
out_free: kfree(newts); return err; @@ -1109,6 +1171,8 @@ static void seg6_local_destroy_state(struct lwtunnel_state *lwt) { struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
- seg6_local_lwtunnel_destroy_state(slwt);
- destroy_attrs(slwt);
return;
Thank you, Andrea