[PATCH v2] wifi: nl80211: clean up coalescing rule handling

[Johannes Berg <johannes@xxxxxxxxxxxxxxxx>]

From: Johannes Berg <johannes.berg@xxxxxxxxx>

There's no need to allocate a tiny struct and then
an array again, just allocate the two together and
use __counted_by(). Also unify the freeing.

Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
v2: don't free embedded rules
---
 include/net/cfg80211.h |  2 +-
 net/wireless/core.c    |  3 ++-
 net/wireless/nl80211.c | 47 ++++++++++++++----------------------------
 net/wireless/nl80211.h |  4 ++--
 4 files changed, 21 insertions(+), 35 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index d79180bec7a1..5da9bb0ac6a4 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3566,8 +3566,8 @@ struct cfg80211_coalesce_rules {
  * @n_rules: number of rules
  */
 struct cfg80211_coalesce {
-	struct cfg80211_coalesce_rules *rules;
 	int n_rules;
+	struct cfg80211_coalesce_rules rules[] __counted_by(n_rules);
 };
 
 /**
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 61f7cd8a8e9c..7c35349b9596 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1145,7 +1145,8 @@ void wiphy_unregister(struct wiphy *wiphy)
 	flush_work(&rdev->background_cac_abort_wk);
 
 	cfg80211_rdev_free_wowlan(rdev);
-	cfg80211_rdev_free_coalesce(rdev);
+	cfg80211_free_coalesce(rdev->coalesce);
+	rdev->coalesce = NULL;
 }
 EXPORT_SYMBOL(wiphy_unregister);
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 6ba988a6f5a2..8ff5f79d446a 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -13897,9 +13897,8 @@ static int nl80211_get_coalesce(struct sk_buff *skb, struct genl_info *info)
 	return -ENOBUFS;
 }
 
-void cfg80211_rdev_free_coalesce(struct cfg80211_registered_device *rdev)
+void cfg80211_free_coalesce(struct cfg80211_coalesce *coalesce)
 {
-	struct cfg80211_coalesce *coalesce = rdev->coalesce;
 	int i, j;
 	struct cfg80211_coalesce_rules *rule;
 
@@ -13908,13 +13907,13 @@ void cfg80211_rdev_free_coalesce(struct cfg80211_registered_device *rdev)
 
 	for (i = 0; i < coalesce->n_rules; i++) {
 		rule = &coalesce->rules[i];
+		if (!rule)
+			continue;
 		for (j = 0; j < rule->n_patterns; j++)
 			kfree(rule->patterns[j].mask);
 		kfree(rule->patterns);
 	}
-	kfree(coalesce->rules);
 	kfree(coalesce);
-	rdev->coalesce = NULL;
 }
 
 static int nl80211_parse_coalesce_rule(struct cfg80211_registered_device *rdev,
@@ -14012,17 +14011,16 @@ static int nl80211_set_coalesce(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	const struct wiphy_coalesce_support *coalesce = rdev->wiphy.coalesce;
-	struct cfg80211_coalesce new_coalesce = {};
-	struct cfg80211_coalesce *n_coalesce;
-	int err, rem_rule, n_rules = 0, i, j;
+	struct cfg80211_coalesce *new_coalesce;
+	int err, rem_rule, n_rules = 0, i;
 	struct nlattr *rule;
-	struct cfg80211_coalesce_rules *tmp_rule;
 
 	if (!rdev->wiphy.coalesce || !rdev->ops->set_coalesce)
 		return -EOPNOTSUPP;
 
 	if (!info->attrs[NL80211_ATTR_COALESCE_RULE]) {
-		cfg80211_rdev_free_coalesce(rdev);
+		cfg80211_free_coalesce(rdev->coalesce);
+		rdev->coalesce = NULL;
 		rdev_set_coalesce(rdev, NULL);
 		return 0;
 	}
@@ -14033,47 +14031,34 @@ static int nl80211_set_coalesce(struct sk_buff *skb, struct genl_info *info)
 	if (n_rules > coalesce->n_rules)
 		return -EINVAL;
 
-	new_coalesce.rules = kcalloc(n_rules, sizeof(new_coalesce.rules[0]),
-				     GFP_KERNEL);
-	if (!new_coalesce.rules)
+	new_coalesce = kzalloc(struct_size(new_coalesce, rules, n_rules),
+			       GFP_KERNEL);
+	if (!new_coalesce)
 		return -ENOMEM;
 
-	new_coalesce.n_rules = n_rules;
+	new_coalesce->n_rules = n_rules;
 	i = 0;
 
 	nla_for_each_nested(rule, info->attrs[NL80211_ATTR_COALESCE_RULE],
 			    rem_rule) {
 		err = nl80211_parse_coalesce_rule(rdev, rule,
-						  &new_coalesce.rules[i]);
+						  &new_coalesce->rules[i]);
 		if (err)
 			goto error;
 
 		i++;
 	}
 
-	err = rdev_set_coalesce(rdev, &new_coalesce);
+	err = rdev_set_coalesce(rdev, new_coalesce);
 	if (err)
 		goto error;
 
-	n_coalesce = kmemdup(&new_coalesce, sizeof(new_coalesce), GFP_KERNEL);
-	if (!n_coalesce) {
-		err = -ENOMEM;
-		goto error;
-	}
-	cfg80211_rdev_free_coalesce(rdev);
-	rdev->coalesce = n_coalesce;
+	cfg80211_free_coalesce(rdev->coalesce);
+	rdev->coalesce = new_coalesce;
 
 	return 0;
 error:
-	for (i = 0; i < new_coalesce.n_rules; i++) {
-		tmp_rule = &new_coalesce.rules[i];
-		if (!tmp_rule)
-			continue;
-		for (j = 0; j < tmp_rule->n_patterns; j++)
-			kfree(tmp_rule->patterns[j].mask);
-		kfree(tmp_rule->patterns);
-	}
-	kfree(new_coalesce.rules);
+	cfg80211_free_coalesce(new_coalesce);
 
 	return err;
 }
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index 6376f3a87f8a..ffaab9a92e5b 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Portions of this file
- * Copyright (C) 2018, 2020-2022 Intel Corporation
+ * Copyright (C) 2018, 2020-2024 Intel Corporation
  */
 #ifndef __NET_WIRELESS_NL80211_H
 #define __NET_WIRELESS_NL80211_H
@@ -119,7 +119,7 @@ nl80211_radar_notify(struct cfg80211_registered_device *rdev,
 
 void nl80211_send_ap_stopped(struct wireless_dev *wdev, unsigned int link_id);
 
-void cfg80211_rdev_free_coalesce(struct cfg80211_registered_device *rdev);
+void cfg80211_free_coalesce(struct cfg80211_coalesce *coalesce);
 
 /* peer measurement */
 int nl80211_pmsr_start(struct sk_buff *skb, struct genl_info *info);
-- 
2.45.1