Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Joseph Hwang <josephsih@chromium.org>
To:     linux-bluetooth@vger.kernel.org, marcel@holtmann.org,
        luiz.dentz@gmail.com, pali@kernel.org
Cc:     josephsih@google.com, chromeos-bluetooth-upstreaming@chromium.org,
        Joseph Hwang <josephsih@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH v9 3/5] Bluetooth: refactor set_exp_feature with a feature table
Date:   Sun, 15 Aug 2021 20:17:15 +0800
Message-Id: <20210815201611.v9.3.Ibd93c7f71f8819d2efdfa3ee2f096319e3c44ea4@changeid>
In-Reply-To: <20210815201611.v9.1.I41aec59e65ffd3226d368dabeb084af13cc133c8@changeid>
References: <20210815201611.v9.1.I41aec59e65ffd3226d368dabeb084af13cc133c8@changeid>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This patch refactors the set_exp_feature with a feature table
consisting of UUIDs and the corresponding callback functions.
In this way, a new experimental feature setting function can be
simply added with its UUID and callback function.

When looking at this patch, please use

  git show --patience

which will display the diff much better than the default
diff-algorithm.

Signed-off-by: Joseph Hwang <josephsih@chromium.org>
---

Changes in v9:
- This version fixes the compile errors of this patch.
  The errors were caused by accidentally messing up my
  development environment.

Changes in v8:
- Refactor the set_exp_feature function with a feature table.
- This is a new patch added in v8.

 net/bluetooth/mgmt.c | 248 +++++++++++++++++++++++++------------------
 1 file changed, 142 insertions(+), 106 deletions(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 1e21e014efd2..42bd503da20d 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3806,7 +3806,7 @@ static const u8 rpa_resolution_uuid[16] = {
 static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
 				  void *data, u16 data_len)
 {
-	char buf[62];	/* Enough space for 3 features */
+	char buf[62];   /* Enough space for 3 features */
 	struct mgmt_rp_read_exp_features_info *rp = (void *)buf;
 	u16 idx = 0;
 	u32 flags;
@@ -3892,150 +3892,186 @@ static int exp_debug_feature_changed(bool enabled, struct sock *skip)
 }
 #endif
 
-static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
-			   void *data, u16 data_len)
+#define EXP_FEAT(_uuid, _set_func)	\
+{					\
+	.uuid = _uuid,			\
+	.set_func = _set_func,		\
+}
+
+/* The zero key uuid is special. Multiple exp features are set through it. */
+static int set_zero_key_func(struct sock *sk, struct hci_dev *hdev,
+			     struct mgmt_cp_set_exp_feature *cp, u16 data_len)
 {
-	struct mgmt_cp_set_exp_feature *cp = data;
 	struct mgmt_rp_set_exp_feature rp;
 
-	bt_dev_dbg(hdev, "sock %p", sk);
-
-	if (!memcmp(cp->uuid, ZERO_KEY, 16)) {
-		memset(rp.uuid, 0, 16);
-		rp.flags = cpu_to_le32(0);
+	memset(rp.uuid, 0, 16);
+	rp.flags = cpu_to_le32(0);
 
 #ifdef CONFIG_BT_FEATURE_DEBUG
-		if (!hdev) {
-			bool changed = bt_dbg_get();
+	if (!hdev) {
+		bool changed = bt_dbg_get();
 
-			bt_dbg_set(false);
+		bt_dbg_set(false);
 
-			if (changed)
-				exp_debug_feature_changed(false, sk);
-		}
+		if (changed)
+			exp_debug_feature_changed(false, sk);
+	}
 #endif
 
-		if (hdev && use_ll_privacy(hdev) && !hdev_is_powered(hdev)) {
-			bool changed = hci_dev_test_flag(hdev,
-							 HCI_ENABLE_LL_PRIVACY);
+	if (hdev && use_ll_privacy(hdev) && !hdev_is_powered(hdev)) {
+		bool changed = hci_dev_test_flag(hdev, HCI_ENABLE_LL_PRIVACY);
 
-			hci_dev_clear_flag(hdev, HCI_ENABLE_LL_PRIVACY);
+		hci_dev_clear_flag(hdev, HCI_ENABLE_LL_PRIVACY);
 
-			if (changed)
-				exp_ll_privacy_feature_changed(false, hdev, sk);
-		}
+		if (changed)
+			exp_ll_privacy_feature_changed(false, hdev, sk);
+	}
 
-		hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
+	hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
 
-		return mgmt_cmd_complete(sk, hdev ? hdev->id : MGMT_INDEX_NONE,
-					 MGMT_OP_SET_EXP_FEATURE, 0,
-					 &rp, sizeof(rp));
-	}
+	return mgmt_cmd_complete(sk, hdev ? hdev->id : MGMT_INDEX_NONE,
+				 MGMT_OP_SET_EXP_FEATURE, 0,
+				 &rp, sizeof(rp));
+}
 
 #ifdef CONFIG_BT_FEATURE_DEBUG
-	if (!memcmp(cp->uuid, debug_uuid, 16)) {
-		bool val, changed;
-		int err;
+static int set_debug_func(struct sock *sk, struct hci_dev *hdev,
+			  struct mgmt_cp_set_exp_feature *cp, u16 data_len)
+{
+	struct mgmt_rp_set_exp_feature rp;
 
-		/* Command requires to use the non-controller index */
-		if (hdev)
-			return mgmt_cmd_status(sk, hdev->id,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_INDEX);
+	bool val, changed;
+	int err;
 
-		/* Parameters are limited to a single octet */
-		if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
-			return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_PARAMS);
+	/* Command requires to use the non-controller index */
+	if (hdev)
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_INDEX);
 
-		/* Only boolean on/off is supported */
-		if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
-			return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_PARAMS);
+	/* Parameters are limited to a single octet */
+	if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
+		return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
 
-		val = !!cp->param[0];
-		changed = val ? !bt_dbg_get() : bt_dbg_get();
-		bt_dbg_set(val);
+	/* Only boolean on/off is supported */
+	if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
+		return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
 
-		memcpy(rp.uuid, debug_uuid, 16);
-		rp.flags = cpu_to_le32(val ? BIT(0) : 0);
+	val = !!cp->param[0];
+	changed = val ? !bt_dbg_get() : bt_dbg_get();
+	bt_dbg_set(val);
 
-		hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
+	memcpy(rp.uuid, debug_uuid, 16);
+	rp.flags = cpu_to_le32(val ? BIT(0) : 0);
 
-		err = mgmt_cmd_complete(sk, MGMT_INDEX_NONE,
-					MGMT_OP_SET_EXP_FEATURE, 0,
-					&rp, sizeof(rp));
+	hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
 
-		if (changed)
-			exp_debug_feature_changed(val, sk);
+	err = mgmt_cmd_complete(sk, MGMT_INDEX_NONE,
+				MGMT_OP_SET_EXP_FEATURE, 0,
+				&rp, sizeof(rp));
 
-		return err;
-	}
+	if (changed)
+		exp_debug_feature_changed(val, sk);
+
+	return err;
+}
 #endif
 
-	if (!memcmp(cp->uuid, rpa_resolution_uuid, 16)) {
-		bool val, changed;
-		int err;
-		u32 flags;
+static int set_rpa_resolution_func(struct sock *sk, struct hci_dev *hdev,
+				   struct mgmt_cp_set_exp_feature *cp,
+				   u16 data_len)
+{
+	struct mgmt_rp_set_exp_feature rp;
+	bool val, changed;
+	int err;
+	u32 flags;
+
+	/* Command requires to use the controller index */
+	if (!hdev)
+		return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_INDEX);
 
-		/* Command requires to use the controller index */
-		if (!hdev)
-			return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_INDEX);
+	/* Changes can only be made when controller is powered down */
+	if (hdev_is_powered(hdev))
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_REJECTED);
 
-		/* Changes can only be made when controller is powered down */
-		if (hdev_is_powered(hdev))
-			return mgmt_cmd_status(sk, hdev->id,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_REJECTED);
+	/* Parameters are limited to a single octet */
+	if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
 
-		/* Parameters are limited to a single octet */
-		if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
-			return mgmt_cmd_status(sk, hdev->id,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_PARAMS);
+	/* Only boolean on/off is supported */
+	if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
 
-		/* Only boolean on/off is supported */
-		if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
-			return mgmt_cmd_status(sk, hdev->id,
-					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_INVALID_PARAMS);
+	val = !!cp->param[0];
 
-		val = !!cp->param[0];
+	if (val) {
+		changed = !hci_dev_test_flag(hdev, HCI_ENABLE_LL_PRIVACY);
+		hci_dev_set_flag(hdev, HCI_ENABLE_LL_PRIVACY);
+		hci_dev_clear_flag(hdev, HCI_ADVERTISING);
 
-		if (val) {
-			changed = !hci_dev_test_flag(hdev,
-						     HCI_ENABLE_LL_PRIVACY);
-			hci_dev_set_flag(hdev, HCI_ENABLE_LL_PRIVACY);
-			hci_dev_clear_flag(hdev, HCI_ADVERTISING);
+		/* Enable LL privacy + supported settings changed */
+		flags = BIT(0) | BIT(1);
+	} else {
+		changed = hci_dev_test_flag(hdev, HCI_ENABLE_LL_PRIVACY);
+		hci_dev_clear_flag(hdev, HCI_ENABLE_LL_PRIVACY);
 
-			/* Enable LL privacy + supported settings changed */
-			flags = BIT(0) | BIT(1);
-		} else {
-			changed = hci_dev_test_flag(hdev,
-						    HCI_ENABLE_LL_PRIVACY);
-			hci_dev_clear_flag(hdev, HCI_ENABLE_LL_PRIVACY);
+		/* Disable LL privacy + supported settings changed */
+		flags = BIT(1);
+	}
 
-			/* Disable LL privacy + supported settings changed */
-			flags = BIT(1);
-		}
+	memcpy(rp.uuid, rpa_resolution_uuid, 16);
+	rp.flags = cpu_to_le32(flags);
 
-		memcpy(rp.uuid, rpa_resolution_uuid, 16);
-		rp.flags = cpu_to_le32(flags);
+	hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
 
-		hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
+	err = mgmt_cmd_complete(sk, hdev->id,
+				MGMT_OP_SET_EXP_FEATURE, 0,
+				&rp, sizeof(rp));
 
-		err = mgmt_cmd_complete(sk, hdev->id,
-					MGMT_OP_SET_EXP_FEATURE, 0,
-					&rp, sizeof(rp));
+	if (changed)
+		exp_ll_privacy_feature_changed(val, hdev, sk);
 
-		if (changed)
-			exp_ll_privacy_feature_changed(val, hdev, sk);
+	return err;
+}
 
-		return err;
+static const struct mgmt_exp_feature {
+	const u8 *uuid;
+	int (*set_func)(struct sock *sk, struct hci_dev *hdev,
+			struct mgmt_cp_set_exp_feature *cp, u16 data_len);
+} exp_features[] = {
+	EXP_FEAT(ZERO_KEY, set_zero_key_func),
+#ifdef CONFIG_BT_FEATURE_DEBUG
+	EXP_FEAT(debug_uuid, set_debug_func),
+#endif
+	EXP_FEAT(rpa_resolution_uuid, set_rpa_resolution_func),
+
+	/* end with a null feature */
+	EXP_FEAT(NULL, NULL)
+};
+
+static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
+			   void *data, u16 data_len)
+{
+	struct mgmt_cp_set_exp_feature *cp = data;
+	size_t i = 0;
+
+	bt_dev_dbg(hdev, "sock %p", sk);
+
+	for (i = 0; exp_features[i].uuid; i++) {
+		if (!memcmp(cp->uuid, exp_features[i].uuid, 16))
+			return exp_features[i].set_func(sk, hdev, cp, data_len);
 	}
 
 	return mgmt_cmd_status(sk, hdev ? hdev->id : MGMT_INDEX_NONE,
-- 
2.33.0.rc1.237.g0d66db33f3-goog