diff mbox series

[RFC,v5,net-next,06/23] net: sched: act_api: Add support for preallocated dynamic action instances

Message ID 20230801113807.85473-7-jhs@mojatatu.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series Introducing P4TC | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1386 this patch: 1386
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 1353 this patch: 1353
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1425 this patch: 1425
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 94 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jamal Hadi Salim Aug. 1, 2023, 11:37 a.m. UTC 
In P4, actions are assumed to pre exist and have an upper bound number of
instances.

Add the necessary code to preallocate actions instances for dynamic actions.

We add 2 new actions flags:
- TCA_ACT_FLAGS_PREALLOC: Which tells if the actions instance was
  preallocated.
- TCA_ACT_FLAGS_UNUSED: Which tells if the actions instance was
  preallocated but not used yet.

The rule is that preallocated actions can't be deleted by the tc actions
runtime commands and a dump or a get will only show preallocated actions
instances which are being used (TCA_ACT_FLAGS_UNUSED == false).

The preallocated actions will be deleted once the dynamic action kind to
which they belong to is deleted.

Co-developed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Co-developed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 include/net/act_api.h |  3 +++
 net/sched/act_api.c   | 46 ++++++++++++++++++++++++++++++++-----------
 2 files changed, 38 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/include/net/act_api.h b/include/net/act_api.h
index b83e058a3..a6331cc5d 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -68,6 +68,8 @@  struct tc_action {
 #define TCA_ACT_FLAGS_REPLACE	(1U << (TCA_ACT_FLAGS_USER_BITS + 2))
 #define TCA_ACT_FLAGS_NO_RTNL	(1U << (TCA_ACT_FLAGS_USER_BITS + 3))
 #define TCA_ACT_FLAGS_AT_INGRESS	(1U << (TCA_ACT_FLAGS_USER_BITS + 4))
+#define TCA_ACT_FLAGS_PREALLOC	(1U << (TCA_ACT_FLAGS_USER_BITS + 5))
+#define TCA_ACT_FLAGS_UNUSED	(1U << (TCA_ACT_FLAGS_USER_BITS + 6))
 
 /* Update lastuse only if needed, to avoid dirtying a cache line.
  * We use a temp variable to avoid fetching jiffies twice.
@@ -202,6 +204,7 @@  int tcf_idr_create_from_flags(struct tc_action_net *tn, u32 index,
 			      const struct tc_action_ops *ops, int bind,
 			      u32 flags);
 void tcf_idr_insert_many(struct tc_action *actions[]);
+void tcf_idr_insert_n(struct tc_action *actions[], const u32 n);
 void tcf_idr_cleanup(struct tc_action_net *tn, u32 index);
 int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index,
 			struct tc_action **a, int bind);
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 3ce586331..bc9fab75b 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -560,6 +560,8 @@  static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
 			continue;
 		if (IS_ERR(p))
 			continue;
+		if (p->tcfa_flags & TCA_ACT_FLAGS_UNUSED)
+			continue;
 
 		if (jiffy_since &&
 		    time_after(jiffy_since,
@@ -640,6 +642,9 @@  static int tcf_del_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
 	idr_for_each_entry_ul(idr, p, tmp, id) {
 		if (IS_ERR(p))
 			continue;
+		if (p->tcfa_flags & TCA_ACT_FLAGS_PREALLOC)
+			continue;
+
 		ret = tcf_idr_release_unsafe(p);
 		if (ret == ACT_P_DELETED)
 			module_put(ops->owner);
@@ -1367,26 +1372,38 @@  static const struct nla_policy tcf_action_policy[TCA_ACT_MAX + 1] = {
 	[TCA_ACT_HW_STATS]	= NLA_POLICY_BITFIELD32(TCA_ACT_HW_STATS_ANY),
 };
 
+static void tcf_idr_insert_1(struct tc_action *a)
+{
+	struct tcf_idrinfo *idrinfo;
+
+	idrinfo = a->idrinfo;
+	mutex_lock(&idrinfo->lock);
+	/* Replace ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc if
+	 * it is just created, otherwise this is just a nop.
+	 */
+	idr_replace(&idrinfo->action_idr, a, a->tcfa_index);
+	mutex_unlock(&idrinfo->lock);
+}
+
 void tcf_idr_insert_many(struct tc_action *actions[])
 {
 	int i;
 
 	for (i = 0; i < TCA_ACT_MAX_PRIO; i++) {
-		struct tc_action *a = actions[i];
-		struct tcf_idrinfo *idrinfo;
-
-		if (!a)
+		if (!actions[i])
 			continue;
-		idrinfo = a->idrinfo;
-		mutex_lock(&idrinfo->lock);
-		/* Replace ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc if
-		 * it is just created, otherwise this is just a nop.
-		 */
-		idr_replace(&idrinfo->action_idr, a, a->tcfa_index);
-		mutex_unlock(&idrinfo->lock);
+		tcf_idr_insert_1(actions[i]);
 	}
 }
 
+void tcf_idr_insert_n(struct tc_action *actions[], const u32 n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		tcf_idr_insert_1(actions[i]);
+}
+
 struct tc_action_ops *tc_action_load_ops(struct net *net, struct nlattr *nla,
 					 bool police, bool rtnl_held,
 					 struct netlink_ext_ack *extack)
@@ -2033,6 +2050,13 @@  tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 			ret = PTR_ERR(act);
 			goto err;
 		}
+		if (event == RTM_DELACTION &&
+		    act->tcfa_flags & TCA_ACT_FLAGS_PREALLOC) {
+			ret = -EINVAL;
+			NL_SET_ERR_MSG_FMT(extack,
+					   "Unable to delete preallocated action %s\n",
+					   act->ops->kind);
+		}
 		attr_size += tcf_action_fill_size(act);
 		actions[i - 1] = act;
 	}