From: Radoslaw Biernacki <rad@semihalf.com>
Date: Tue, 1 Feb 2022 20:10:33 +0000
Subject: Bluetooth: Improve skb handling in mgmt_device_connected()
Patch-mainline: v5.18-rc1
Git-commit: c2b2a1a77f6b2694b7249073083ad6a0c918eef3
References: jsc#PED-1407

This patch introduce eir_skb_put_data() that can be used to simplify
operations on eir in goal of eliminating the necessity of intermediary
buffers.
eir_skb_put_data() is in pair to what eir_append_data() does with help of
eir_len, but without awkwardness when passing return value to skb_put() (as
it returns updated offset not size).

Signed-off-by: Radoslaw Biernacki <rad@semihalf.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
 net/bluetooth/eir.h  |   15 +++++++++++++++
 net/bluetooth/mgmt.c |   25 ++++++++-----------------
 2 files changed, 23 insertions(+), 17 deletions(-)

--- a/net/bluetooth/eir.h
+++ b/net/bluetooth/eir.h
@@ -41,6 +41,21 @@ static inline u16 eir_append_le16(u8 *ei
 	return eir_len;
 }
 
+static inline u16 eir_skb_put_data(struct sk_buff *skb, u8 type, u8 *data, u8 data_len)
+{
+	u8 *eir;
+	u16 eir_len;
+
+	eir_len	= eir_precalc_len(data_len);
+	eir = skb_put(skb, eir_len);
+	WARN_ON(sizeof(type) + data_len > U8_MAX);
+	eir[0] = sizeof(type) + data_len;
+	eir[1] = type;
+	memcpy(&eir[2], data, data_len);
+
+	return eir_len;
+}
+
 static inline void *eir_get_data(u8 *eir, size_t eir_len, u8 type,
 				 size_t *data_len)
 {
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -9111,18 +9111,12 @@ void mgmt_device_connected(struct hci_de
 		skb_put_data(skb, conn->le_adv_data, conn->le_adv_data_len);
 		eir_len = conn->le_adv_data_len;
 	} else {
-		if (name_len > 0) {
-			eir_len = eir_append_data(ev->eir, 0, EIR_NAME_COMPLETE,
-						  name, name_len);
-			skb_put(skb, eir_len);
-		}
+		if (name)
+			eir_len += eir_skb_put_data(skb, EIR_NAME_COMPLETE, name, name_len);
 
-		if (memcmp(conn->dev_class, "\0\0\0", 3) != 0) {
-			eir_len = eir_append_data(ev->eir, eir_len,
-						  EIR_CLASS_OF_DEV,
-						  conn->dev_class, 3);
-			skb_put(skb, 5);
-		}
+		if (memcmp(conn->dev_class, "\0\0\0", sizeof(conn->dev_class)))
+			eir_len += eir_skb_put_data(skb, EIR_CLASS_OF_DEV,
+						    conn->dev_class, sizeof(conn->dev_class));
 	}
 
 	ev->eir_len = cpu_to_le16(eir_len);
@@ -9822,13 +9816,10 @@ void mgmt_remote_name(struct hci_dev *hd
 	ev->addr.type = link_to_bdaddr(link_type, addr_type);
 	ev->rssi = rssi;
 
-	if (name) {
-		eir_len = eir_append_data(ev->eir, 0, EIR_NAME_COMPLETE, name,
-					  name_len);
-		skb_put(skb, eir_len);
-	} else {
+	if (name)
+		eir_len += eir_skb_put_data(skb, EIR_NAME_COMPLETE, name, name_len);
+	else
 		flags = MGMT_DEV_FOUND_NAME_REQUEST_FAILED;
-	}
 
 	ev->eir_len = cpu_to_le16(eir_len);
 	ev->flags = cpu_to_le32(flags);