2022-02-02 23:50:31

by Radosław Biernacki

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Subject: [PATCH v3 2/2] Bluetooth: Improve skb handling in mgmt_device_connected()

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 <[email protected]>
---
net/bluetooth/eir.h | 15 +++++++++++++++
net/bluetooth/mgmt.c | 25 ++++++++-----------------
2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/net/bluetooth/eir.h b/net/bluetooth/eir.h
index e5876751f07e..43f1945bffc5 100644
--- a/net/bluetooth/eir.h
+++ b/net/bluetooth/eir.h
@@ -41,6 +41,21 @@ static inline u16 eir_append_le16(u8 *eir, u16 eir_len, u8 type, u16 data)
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)
{
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 43ca228104ce..4a24159f7dd6 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -9087,18 +9087,12 @@ void mgmt_device_connected(struct hci_dev *hdev, struct hci_conn *conn,
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);
@@ -9798,13 +9792,10 @@ void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
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);
--
2.35.0.rc2.247.g8bbb082509-goog